Evaluating the cradle-to-gate Environmental Impact and cooling performance of Advanced Daytime Radiative Cooling Materials to Establish a Comparative Framework for a Novel Photonic Meta-Concrete

Evaluating the cradle-to-gate Environmental Impact and cooling performance of Advanced Daytime Radiative Cooling Materials to Establish a Comparative Framework for a Novel Photonic Meta-Concrete | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Evaluating the cradle-to-gate Environmental Impact and cooling performance of Advanced Daytime Radiative Cooling Materials to Establish a Comparative Framework for a Novel Photonic Meta-Concrete NICK ADAMS, Laura Carlosena, karen Allacker This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4580586/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 08 Oct, 2024 Read the published version in Environmental Sciences Europe → Version 1 posted 12 You are reading this latest preprint version Abstract Background By the end of 2050, it is expected that 68% of the population will live in urban areas. A higher density of people living in cities generates an increased urban heat island. Radiative cooling (RC) materials are proposed as a key strategy to mitigate global warming and urban heating. The Horizon 2020 project MIRACLE aims at developing a new RC material based on conventional concrete. This paper presents a framework developed for comparing both the cradle-to-gate environmental impact and cooling potential of the newly developed photonic meta-concrete (or any other new RC material) with existing RC materials. The framework is applied to various RC materials using the generic Ecoinvent v3.6 database. The impact assessment method is in line with the Belgian life cycle assessment method for buildings and covers the 15 environmental impact categories of the EN15804:A2. The cooling performance is assessed by implementing the material spectral emissivity into a thermal model for Brussels and Madrid. Results Collecting sufficient data to model the state-of-the-art RC materials is challenging, requiring numerous data points on materials, production, and performance, leading to many assumptions due to a lack of data. The study showed that the sputtering process contributes over 75% to the environmental impact of several materials, while materials which do not use this process, have significantly lower impacts. The assessment of the cooling potential showed that convection heat gains make it difficult to create an all-year round cooling material. The comparison with a conventional building material, a concrete roof tile, hence shows great potential for these RC materials as heating gains during summer are significantly reduced. Analysing cooling performance alongside environmental impact, the study identified two RC materials as the most preferred in both Brussels and Madrid, considering their lower environmental impact and superior performance. Conclusions A standardised way to asses and benchmark RC materials based on their cradle-to-gate environmental impact and cooling performance was lacking. For the first time, a comparison for RC materials considering these characteristics is presented. This comparison identified the most competitive RC materials, which will serve as benchmarks for the newly developed photonic meta-concrete. LCA thin film deposition techniques sputter deposition cooling potential Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 1 Introduction Urbanisation is a phenomenon which explains the increase of people living in towns and cities. By the end of 2050, it is expected that 68% of the world's population will be living in urban areas [ 1 ]. A higher density of people living in cities generates more anthropogenic heat production, reduced vegetation and evapotranspiration, and less permeable surfaces, as 60% of cities are constructed out of complex human-made heat absorbing materials [ 2 ]. These factors are well known to be the drivers of the urban heat island (UHI). This effect holds that the temperature of an urban area is higher than the temperature of an adjacent rural area. The consequences of the UHI can be a higher energy demand for cooling, a significant increase in the peak energy demand, the degradation of air quality, an increased thermal stress on residents, the degradation of the urban ecosystem and a higher mortality rate due to the excessive heat [ 3 ]. The UHIs also have an impact outside the boundaries of cities. The International Energy Association (IEA) claims that energy consumption, and the related CO 2 emissions, for space cooling has tripled since 1990, which causes even more greenhouse gas emissions and implications for the electricity grids [ 4 ]. Next to that, cooling also leads to the emission of non-CO 2 greenhouse gasses caused by the leaking of refrigerants, which have a global warming potential of up to thousands of times higher than CO 2 . Mitigation strategies to fight climate change, specifically the UHI, are numerous and have been intensively studied over the past decades. One of the potential mitigation strategies is radiative cooling (RC) materials. RC materials have specific altered photonic properties, making them reflect solar irradiance and emit heat. Using such materials in cities hence allows cities to accumulate less heat from solar irradiance and emit more heat. Therefore, besides reducing energy consumption due to reduced cooling demand, these materials also help mitigating global warming [ 5 ]. The most common application of these materials is roof covering, as the roof is the component with the highest temperature fluctuations [ 6 ] and has a high sky view factor. Solar irradiation, the loss of heat in the infrared during the night and rain all affect the roof more than other building components [ 7 ]. Nahar et al. claimed that a roof can contribute up to 50% of the thermal load for buildings in hot climates [ 8 ]. Radiation is a phenomenon where energy is transmitted in the form of electromagnetic waves due to the change in the atomic or molecular configuration of an object. For heat transfer, thermal radiation refers to the energy transmitted by an object to its surroundings because of the temperature difference between the object and its surroundings [ 9 ]. Radiative cooling is the natural process by which an object emits thermal energy through infrared radiation. Materials designed for daytime radiative cooling can attain sub-ambient temperatures owing to their high solar reflectivity and elevated infrared emissivity. Within the mid-infrared spectrum, specifically in the range of 8 to 13 µm, the Earth's atmosphere allows electromagnetic radiation to pass through without obstruction. This holds that a material can consistently keep dumping heat to stay colder than the surrounding air [ 10 ]. RC materials can be used as passive and active RC materials. The latter describes implementations where the RC material assists an active cooling technology [ 10 ]. In a passive application (focus of this study), the materials are not coupled with any installation and work autonomously. Due to their high solar reflectivity, daytime RC materials have a cooling power throughout the entire cycle of the day instead of only during the night. This is important as the peak cooling demand occurs during the day [ 11 ]. The heating up of the surface is, hence, the biggest challenge for daytime RC materials and therefore, a high solar reflectivity is needed to guarantee that the surface temperature stays below the ambient temperature. To remain at ambient temperature, over 94% of incident short wave radiation must be reflected, especially given variations in atmospheric conditions across different geographic regions [ 11 ]. Zhai et al. claim that the absorbance of just a few per cent already reduces the cooling power and effectively heats the surface [ 12 ]. Liu et al. came to the same conclusion as they stated that solar absorption is the critical factor for daytime RC instead of mid-infrared emissions. They argue that to break through the day and night restriction and achieve all-day RC, high mid-infrared emissions and low solar absorption must be achieved simultaneously [ 5 ]. Next to the challenge of absorbing less heat due to solar irradiance, another big challenge comes along with the design and application of the materials, as most surfaces in contact with the RC material will themselves heat up when exposed to solar radiation and transfer this excessive heat to the RC material [ 11 ]. The Horizon 2020 project MIRACLE (Meta concrete with Infrared Radiative Cooling capacity for Large Energy savings) aims at developing a new passive daytime RC material based on conventional concrete. Using concrete gives advantages from a design perspective as the bulky solution gives more design freedom, but also from a knowledge perspective as concrete is the most used material by mankind. Although using these RC materials sounds promising, some researchers doubt their application. Lim discusses that only a small sample of tests have been carried out to evaluate the effect of RC materials [ 13 ]. There are doubts about the materials' ability to perform well in various climates and places. Lim also highlights that it is unknown whether the consumer will embrace the idea and that the effect of the RC materials might also increase the heating cost during colder periods/seasons [ 13 ]. Liu et al. add the high cost of creating these materials as a problem [ 5 ]. Existing RC materials are moreover made of heavy metals and polymers and are produced using thin film deposition techniques characterised by high energy use and environmental impact. Despite the uncertainties regarding RC materials, daytime RC systems are expected to be the number one building technology in four or five years [ 13 ]. Previous research highlighted that the amount of electricity used in a building for cooling is predicted to decrease by 21% when the roof is covered with RC materials in Las Vegas, Nevada [ 13 ]. A preliminary analysis indicates that RC materials could compete favourably economically against other rooftop renewable energy options for cooling, such as photovoltaic panels, but may also work cooperatively with them [ 11 ]. In order to fully understand the potential of RC materials, insight in their cooling capacity is necessary. There is however no standard yet indicating how the performance of RC materials should be measured. In literature, the performance indicators ‘cooling power drop’ and ‘ambient temperature drop’ are used, but a significant variation is identified in how these are measured. Both average and maximum values are found in literature, and the wavelength is not always specified, which makes it impossible to compare the performance of the materials [ 5 ]. Moreover, experiments are carried out in specific climate and weather conditions, not providing any information on their performance under different conditions. There is hence a need for a standard method to evaluate and compare the cooling performance of RC materials. Carlosena et al. [ 14 ] however recently proposed for the first time a method to compare the performance of RC materials under the same conditions. Carlosena et al. propose spectral emissivity to characterise the performance of multiple RC materials under the same weather conditions. This method is used in this paper to assess the performance of various RC materials. As mentioned in literature, RC materials are typically made of heavy metals using thin film deposition techniques, potentially causing a high environmental impact. In order to select the preferred RC material, hence not only the performance should be known, but also its environmental impact. No studies have however been performed on the environmental impact of RC materials. This is the second focus of this paper. More specifically, in order to better understand how the various RC materials on the market perform in terms of cooling capacity in relation to their environmental impact a comparative framework is developed. This framework can be used during the development of the new PMC, and for any other innovative RC material in future. 2 Methodology To assess the performance in terms of environmental impact and cooling capacity of the newly developed PMC and compare it with existing RC materials, first a selection of existing RC materials is made. Secondly, the environmental impact (EI) is assessed for 1 dm² of each RC material selected, as this is the area that can be manufactured using the production techniques described below. A cradle-to-gate environmental impact assessment is performed: the system boundaries only contain the materials and production processes until the finished product. No cleaning, maintenance, labour or transport is taken into account. Thirdly, the cooling performance of each material under identical conditions in two different locations is assessed. Finally, the EI is compared with the cooling performances to identify the preferred RC material for each location. To complete the comparison, a conventional concrete roof tile is considered for both the EI assessment and the evaluation of cooling performance. This tile represents common practice in roof finishing, providing an initial indication of the competitiveness of these new materials against existing options. The modelling and EI assessment of the RC materials is performed in two steps. Firstly, the materials are selected based on predefined criteria and secondly, the materials and their production processes are modelled and the single score environmental impact (SSEI) is assessed. 2.1 Radiative Cooling material selection Passive daytime RC materials are selected from state-of-the-art cooling materials described in scientific papers in the field. All materials identified in the literature study were considered, but only those for which sufficient data was available for the EI assessment were selected for analysis. The data required for the EI assessment are, amongst others, the amount of material, the production processes, the net cooling power and the photonic properties. The sources for the data collection were literature, including contact with the authors of the publications of the selected RC materials and experts in the field (see acknowledgements). The literature study resulted in nineteen RC materials, only ten daytime RC materials were selected to model for the database due to the lack of data for the others. 2.2 Modelling and environmental impact assessment of radiative cooling materials 2.2.1 Modelling The selected RC materials are modelled using the generic Ecoinvent v3.6 life cycle inventory database. European data records are used if available, and global records are used if there is no other option. If multiple records are available, the decision is made based on information and requirements of the production process and experts' feedback. The ten selected RC materials are manufactured by various thin film deposition techniques, such as sputter deposition, ion beam deposition, electron beam deposition, spin coating, phase inversion and roll-to-roll deposition. Information on each of these techniques is searched in literature and by consulting experts. This mainly involves the amount of material needed, the efficiency of the process, the energy use and potential emissions. The processes are briefly described in the subsequent paragraphs. 2.2.2.1 Sputter deposition Sputter deposition, or shortly sputtering, takes place in a vacuum system where a target, the source material that will be deposited, and a substrate, where the source material will be deposited upon, are placed. Argon gas is inserted into the chamber, and a high negative voltage is applied onto this target. This high negative voltage will strip an electron from the argon gas and ionises the argon atoms. The negatively charged target then attracts these positive ions and will gain enough speed to knock off source materials. These atoms will fly off in all directions, including toward the substrate. Multiple variables need to be taken into account to model this process: the amount of material, the amount of energy, the gas to fill the vacuum chamber, the time of deposition, the kind of material that is being deposited and the substrate. Eight of the ten daytime RC materials are produced using a sputtering process. Previous research clearly indicated that sputtering processes are poorly represented in the generic Ecoinvent v3.6 database [ 15 ]. A sputtering process is, therefore, modelled in this research. Ion beam deposition and electron beam evaporation belong to the same group of thin film deposition techniques as sputter deposition. Therefore, these processes are modelled as sputter deposition processes (recommendation of experts), as ion beam deposition and electron beam evaporation are not or poorly represented in the generic Ecoinvent database. The sputtering process is expected to be a good proxy, as the vacuum system and energy consumption, which generate the highest environmental impact [ 16 ], are similar for all three processes. 2.2.2.2 Spin coating deposition Spin coating is a thin film deposition technique that applies uniform thin films to flat substrates. The process typically involves depositing a small puddle of a fluid onto the centre of a substrate and then spinning the substrate at high speed to create the thin film. The typical speed is around 3000 rpm [ 17 ]. Only one selected RC material is manufactured using spin coating. The spin coating process is unavailable in the Ecoinvent v3.6 database and has been modelled in this research. 2.2.2.3 Phase inversion methods Phase inversion is a method where polymer transformation occurs from a liquid phase to a solid phase. The first step is to prepare a homogenous polymer solution by dissolving the polymer in a solvent. By using an external or internal factor, the phase inversion is induced. External factor methods are nonsolvent-induced precipitation, precipitation from the vapour phase, and thermally-induced phase separation. The main internal factor method is evaporation-induced phase inversion [ 18 ]. Two of the ten selected materials are manufactured using a phase inversion method. The Ecoinvent database does not include a phase inversion method; hence, this technique has been modelled in this research. 2.2.2.4 Roll to roll deposition Roll-to-roll processing is a class of substrate-based manufacturing processes in which additive and subtractive processes are used to build structures continuously [ 19 ]. The production process consists of numerous processing chambers with stable conditions, in which the substrate is transported continuously from one chamber to the next to go through different thin film deposition processes, amongst others, sputter deposition [ 20 ]. One of the selected materials is manufactured using roll-to-roll deposition. It is important to note that this roll-to-roll deposition technique is already a technology at the industrial scale, while the other deposition techniques are still at lab-scale. It might, hence be that the impact of the other techniques is overestimated compared to this one. This roll to roll deposition process is again not available in the Ecoinvent database and has been modelled in this research. 2.2.3 Environmental impact assessment The materials and their production processes mentioned above are modelled in the Simapro software. The final input of the materials modelled is presented in the additional file: Table S1 . The cradle-to-gate environmental impact of the ten RC materials is assessed using the impact categories of the EN15804 + A2 standard; these categories are summarised in Table 1 . More specifically, a single score environmental impact is studied in detail to enable a comparison in case of contradictory indicators. This single score is calculated using the EC PEF method normalisation and weighting factors [ 21 ], also presented in Table 1 . We acknowledge the inherent subjectivity in the weighting of environmental indicators. Therefore, we provide the results for each impact category separately in the additional file for transparency (Tables S4.1-S4.10 and Figures S1 -S8). Table 1 Environmental impact categories of the EN15804 + A2 standard Impact category Unit Normalisation factor Weighting factor Climate change kg CO2 eq 0.0001235 0.2106 Ozone depletion kg CFC11 eq 18.64 0.0631 Ionising radiation kBq U-235 eq 0.0002370 0.0501 Photochemical ozone formation kg NMVOC eq 0.02463 0.0478 Particulate matter Disease inc. 1680 0.0896 Human toxicity, non-cancer CTUh 4354 0.0184 Human toxicity, cancer CTUh 59173 0.0213 Acidification mol H + eq 0.018 0.062 Eutrophication, freshwater kg P eq 0.6223 0.028 Eutrophication, marine kg N eq 0.05116 0.0296 Eutrophication, terrestrial Mol N eq 0.005658 0.0371 Ecotoxicity, freshwater, CTUe 0.00002343 0.0192 Land use Pt 0.000001220 0.0794 Resource use, fossils MJ 0.00001538 0.0832 2.3 Cooling Potential To effectively compare the environmental impact of the newly developed PMC with existing RC materials, it is imperative to account for their cooling performance. Cooling performance is typically quantified regarding cooling power, expressed in watts per square meter (W·m − 2 ) or as a temperature differential relative to the ambient temperature. The literature review revealed that the method used to determine the cooling performance for the selected RC materials varies, utilising both theoretical and experimental methods and accounting for different atmospheric and climatic conditions. As a result, the cooling power or temperature drops reported in literature cannot be used to compare the various RC materials or for benchmarking purposes. In order to facilitate a meaningful cooling performance comparison among the RC materials, this paper determines the cooling performance in an identical way under the same climatic conditions for each RC material using the approach and thermal model proposed by Carlosena et al. [ 14 ]. The recent study on the worldwide potential of RC materials by Carlosena et al. [ 22 ] introduced RC materials on top of a conductive surface with a given temperature to represent the comfort temperature inside a building during a cooling or heating period. The monthly accumulated heat gains and losses are calculated to determine the cooling potential of the materials. As output, the model presents the monthly accumulated energy exchanged (kWh·m − 2 ) by the surface to its surroundings. A negative energy exchange holds net cooling of the surface and, therefore, radiative cooling. The model of Carlosena et al. was used in this paper fed with the following information: spectral emissivity, weather data of each location, and surface temperature of the conductive surface. First, the spectral emissivity of the RC materials (presented in the additional file: Table S2) was provided to the model as the average emissivity in 39 unique wavebands, which cover the entire spectrum. Secondly, two cities with temperate climate conditions were chosen: Brussels (Belgium) and Madrid (Spain). The weather data of each location including temperature, relative humidity, solar radiation, sky cover, and wind speed were used to calculate the materials' cooling potential. The climates of the selected cities were obtained from Meteonorm [ 23 ] as TMY2 files. The months of January and July were selected as they represent a winter and summer scenario. Finally, to calculate the temperature of the conductive surface, the geometry of the KUBIK test building (Tecnalia, Bilbao) is used and is modelled as a non-insulated concrete building with a heating and cooling installation. It is assumed that the RC material is put on the flat roof, hence the monthly average outdoor roof surface temperature was calculated using EnergyPlus. The building is only heated in January with a minimum temperature of 21°C and cooled in July with a maximum temperature of 25°C. The heating and cooling system works from 7:00 until 23:00 for both months. A realistic cooling and heating pattern is assumed by using this setup. The standard concrete roof slab from the EnergyPlus database is used to represent the surface temperature of the concrete roof tile. From this point on, the temperature of this concrete slab will be presented as the temperature of the concrete roof tile. Similarly, a standard concrete roof slab covered with an RC material is used to represent the surface temperature of the RC materials. The albedo and emissivity considered for the concrete roof were 0.65 and 0.9, respectively, which are the same values as for a concrete roof tile. For the RC materials, the albedo and emissivity were 0.85 and 0.95, respectively. These latter values align with the photonic properties of the selected materials. The resulting temperatures for the concrete roof tile are higher, as this material has a lower reflectivity and a slightly lower emissivity. The utilised temperatures for the validated heat transfer model [ 14 ] are presented in Table 2 . For the RC materials, the temperatures were 2.51°C in Brussels and 4.5°C in Madrid in winter; and. 17.38°C in Brussels and 24.10°C in Madrid in summer. Comparing the average roof surface temperature for the concrete roof tile and the cooling materials shows a decrease in temperature up to 6°C and 8°C for Brussels and Madrid respectively. Table 2 Monthly average roof surface temperature calculated for the conductive surface for an average RC material and a concrete roof tile in Brussels and Madrid. Monthly average roof surface temperature (°C) January July Brussels Concrete tile 3.30 23.79 RC materials 2.51 17.38 Madrid Concrete tile 7.54 32.99 RC materials 4.51 24.10 2.4. Comparative framework Finally, the environmental impact of the RC materials and the concrete roof tile, calculated in section 2.2 , and their cooling performance, calculated in section 2.3 , are combined. A Pareto front is used to determine the optimal materials for two months and the selected cities. The Pareto front method enables us to identify materials that strike an optimal balance without compromising one parameter for the sake of the other. During the summer months, the preferred material exhibits a commendable combination of low environmental impact and high cooling performance. This equilibrium is aligned with the seasonal demand for effective cooling solutions, emphasising sustainability and energy efficiency during warm periods. In contrast, the winter season necessitates a distinct strategy. Here, the focus shifts towards minimising cooling performance to mitigate the heating penalty attributed to cooling materials. This approach reflects the evolving heating and cooling requirements across seasons and underscores the importance of adaptability in addressing environmental concerns. The pareto front considering the environmental impact in the five selected impact categories is presented in the additional information: Figures S9-S13. 3 Results 3.1 Modelling and environmental impact assessment of radiative cooling materials 3.1.1 Radiative cooling material selection Table 3 shows the ten daytime RC materials considered. In the first column, the name used in this paper is mentioned, followed by the number of layers, the deposited materials, the thickness of each layer and the production process of each layer. The production process is not given for every layer, but the materials are still considered for the modelling and the environmental impact. It is, hence, necessary to assume a production process based on the characteristics of the layer. The assumptions are made based on the thicknesses or best guesses. Material D2, for example, has stacked layers with thicknesses in the magnitude of nanometres. It can, therefore, be assumed that a thin film deposition technique like sputtering is used. Material D6 and D7 are based on the paper of Mandal et al. As they discuss multiple materials to create an RC material, a worst-case (D7) and best-case (D6) scenario are chosen based on the environmental impact of the materials [ 24 ]. Table 3 Selected passive daytime radiative cooling materials. Name composition source # layers Material Thickness of each layer Process Modelled process D1 4 TiO 2 20–300 nm Electron beam evaporation Sputter deposition [ 25 ] 3 SiO 2 20–300 nm Electron beam evaporation Sputter deposition 1 Ag 50 nm / Sputter deposition 1 Si-wafer / / / D2 31 TiO 2 20–220 nm / Sputter deposition [ 25 ] 31 SiO 2 50–401 nm / Sputter deposition 1 Ag 100 nm / Sputter deposition 1 Si-wafer / / / D3 1 Quartz 2500 nm Roll-to-roll Sheet rolling (only energy use) [ 26 ] 1 SiC 8000 nm Roll-to-roll Sheet rolling (only energy use) 15 TiO 2 25–75 nm / Sputter deposition 15 MgF 2 35–105 nm / Sputter deposition 1 Ag 50 nm / Sputter deposition D4 1 TPX with 6% SiO 2 spheres 2500 nm Sheet rolling Sheet rolling [ 27 ] 1 Ag 200 nm Electron beam evaporation Sputter deposition D5 1 PDMS 100 µm Spin coating Spin coating [ 28 ] 1 Si-wafer 500 µm / / 1 silver 120 nm Electron beam evaporation Sputter deposition D6 1 PET 300 µm Phase inversion method Phase inversion method [ 24 ] 1 Steel 100 µm / Sheet rolling D7 1 Polyvinyl fluoride 500 µm Phase inversion method Phase inversion method [ 24 ] 1 Al 200 µm / Sheet rolling D8 11 SiO 2 113–462 nm Electron beam evaporation Sputter deposition [ 29 ] 11 Si 20–97 nm Electron beam evaporation Sputter deposition 1 Si-wafer 500 µm / / D9 4 SiO 2 54–230 nm Electron beam evaporation Sputter deposition [ 11 ] 3 TiO 2 34–485 nm Electron beam evaporation Sputter deposition 1 Ti 20 nm Electron beam evaporation Sputter deposition 1 Ag 200 nm Electron beam evaporation Sputter deposition 5 Si-wafer 750 µm / / D10 4 SiO 2 314–951 nm Electron beam evaporation Sputter deposition [ 30 ] 3 TiO 2 378–782 nm Electron beam evaporation Sputter deposition 1 Ag 100 nm Electron beam evaporation Sputter deposition 1 Si-wafer / / / 3.1.2 Modelling The different thin film deposition techniques have first been modelled individually. The amount of materials and the specific data records for the raw materials are chosen based on the collected information. 3.1.2.1 Sputter deposition Sputtering is a thin film deposition technique in the same category as thermal evaporation and ion beam evaporation. As these processes are comparable and all the RC materials can be deposited by either one of them, only the sputtering deposition is modelled and applied to all thin films in the database. Moreover, the Leuven NanoCentre uses sputtering and could provide detailed information on the process. After checking the characteristics of the layers with unknown production processes for RC materials D1, D2 and D3, sputter deposition is also assumed for these layers. These thin layers will probably be manufactured by one of the above-mentioned techniques. Each step in the complex sputtering process has first been modelled separately. The amount of material, substrate, number of depositions in one process, the amount of argon gas and energy used during the deposition are described in the subsequent paragraphs. Materials The sputter efficiency is assumed to be 50% by recommendation of experts and as mentioned by Mattox (2010) [ 31 ]. The amount of material for each layer is calculated by dividing the density of the materials by the volume of the layer. This is then doubled because of the 50% efficiency. Either virgin metals or metal oxides can be used as target material. Virgin metals are used in this research (recommendation of experts). Substrate During a sputtering process, the target material must always be deposited on top of an already existing layer, the substrate. These substrates can be removed afterwards only to have the deposited materials. The RC materials presented here are deposited on top of a silicon wafer, as this contributes to the performance of the RC materials. Four of the seven RC materials manufactured using a thin film deposition technique already mention this silicon wafer as a substrate. This wafer is also added to the other three materials. The thickness of this wafer is assumed to be 240 µm as this is the standard thickness of the silicon wafer in the Ecoinvent database. Number of depositions in one process The sputtering record in the Ecoinvent v3.6 database is based on rough estimations and data provided by a German manufacturer; the specific sputtering machine is unknown. The record describes that a new process needs to be accounted for every new deposited layer. However, according to the Leuven NanoCentre, up to three different materials can be deposited in alternating layers during one process. Other existing sputtering machines, like the spider 6000 [ 32 ] and existing research on sputtering [ 33 ] confirm that multiple materials can be deposited in alternating layers in a single deposition process. In this paper, a single deposition process is hence accounted for every RC material. Argon gas Gas is inserted during the sputter deposition to create a plasma and knock off target materials. Argon is used because it is inert and does not react with other materials. Although the rate of inserted argon gas is target material dependent, a single value for the rate of inserted argon gas for all materials is considered. This is assumed to be an acceptable simplification as the contribution to the environmental impact of sputtering by the use of argon gas is negligible [ 34 ]. An average rate of 50 cc/min is used during deposition, according to the experts. This amount is assumed in our model, as indicated in Table 4 . The same amount of argon gas is assumed as emissions (recommendation of experts). Energy use during deposition The Ecoinvent record 'Selective coat, copper sheet, sputter deposition {DE}| selective coating, copper sheet, sputtering | Cut-off, U' accounts for 3.47 kWh per deposition process [ 35 ]. As this amount of energy use is very uncertain, a detailed calculation of the energy use based on the process details has been made as described in the subsequent paragraphs. A sputtering process exists in three phases. First, a vacuum is created in the chamber by using pumps. These pumps hold the chamber in vacuum during the deposition. This is further called the "energy use of the pumps". Secondly, energy is needed to heat the target during the deposition. Sputtering yields can be used to calculate the amount of energy needed to make a deposition of a certain thickness; these yields are used to estimate the energy demand. This process is further called "the energy use of the target". Finally, the substrate and the machines need to cool down. This is further referred to as "the energy use for cooling". Merlo et al. assume a power of the pumps of 4 to 8 kW[ 34 ] [ 36 ], by considering the combination of a mechanical rotary vane pump and a turbomolecular pump. Fiameni et al. account for 10 kWh for this pumping energy[ 33 ] without mentioning the time required for the deposition, making it impossible to use this information to estimate the energy use for the pumps. In this paper, a pumping power of 4 kW is assumed. To pump the chamber to vacuum, a conservative time of 45 minutes is assumed [ 37 ], confirmed by the experts, resulting in an energy use of 3 kWh. Furthermore, the deposition time is estimated to calculate the total energy use of the pump (see next paragraph). The estimation of the energy use for the target is complex. Every material and sputtering machine has different sputtering rates. Therefore, it is not feasible to choose a specific rate for every material and every sputtering machine. The rates mentioned for four sputtering machines [ 15 , 19 – 21 ] [ 32 ][ 38 ] [ 39 ] [ 40 ] and two papers [ 41 ] [ 42 ] are gathered and the average is calculated. This results in a sputtering rate of 0.406 nm/s with a power of 435.83 W. This is in line with the data from the Leuven NanoCetre, specifically an average of 0.55 nm/s with a power of 100-200W. This average rate is assumed in this paper for every material. The total sputtering time is estimated by dividing the thickness of the material by the rate. This sputtering time (in seconds) is then used to calculate the energy used for the target heating and for the pump to keep the room vacuumed during sputtering. Finally, the energy used for the cooling down of the process is estimated. Merlo et al. assume 20 min and a power of 2 kW for the cooling down of the material, resulting in a total power of 0.67 kWh [ 36 ]. Fiameni et al. assume 0.3 kWh for the cooling down [ 33 ]. This paper assumes that 0.3 kWh is required for cooling as the thickness of the deposited layers in the study of Fiameni et al. is closer to the thickness of the layers of the selected RC materials. The amount of gas, time and energy needed for the different materials are summarised in Table 4 . The calculation of all the needed variables to model the sputtering process are presented in the additional file: Table S3. Table 4 Modelling of the sputter deposition process. Material Total sputter thickness (nm) Deposition time (s) Target Energy (kWh) Pumping time (s) Pumping Energy (kWh) Amount of Argon gas (cc) D1 1030 2537.0 0.307 5236.95 5.819 2114.12 D2 10224 25182.3 3.049 27882.27 30.980 20985.22 D3 12350 30419.0 3.684 33118.72 36.799 25348.93 D4 200 492.6 0.060 3192.61 3.547 410.51 D5 120 296.0 0.036 2995.57 3.328 246.31 D8 3813 9391.6 1.137 12091.63 13.435 7826.36 D9 1777 4376.8 0.530 7076.85 7.863 3647.37 D10 5103 12569.0 1.522 15268.97 16.966 10474.14 3.1.2.2 Spin coating deposition Material D5 is the only material where spin coating (in addition to the sputtering step) is used to create one of the thin film layers. Literature indicates that the material efficiency of a spin coating process is low, mentioning material losses between 70% [ 43 ] and 90% [ 44 ] [ 45 ]. A material loss of 80% is assumed in this paper. This means that five times more material is required than needed for the desired layer thickness. Several energy uses were found for spin coating. Gong et al. mention 0.22 kWh/m 2 , 0.51 kWh/m 2 and 0.08 kWh/m 2 [ 43 ]; Espinosa et al. mention 0.5 kWh/m 2 and 99 kWh/m 2 [ 45 ] and Garcia-Valverde et al. mention 0.505 kWh/m 2 [ 46 ]. The median is chosen to balance out the outlier of 99 kWh/m2, resulting in 0.36 kWh/m 2 . As the functional unit is 1 dm 2 , the energy use of 0.0036 kWh/dm 2 is assumed. No information has been found on process emissions in the literature, and no information on these was available from experts in the field. Process emissions have hence not been taken into account. 3.1.2.3 Phase inversion methods Yadav et al. discuss the environmental impact assessment of a phase inversion method [ 18 ]. The information they provided is used as a base for our model but has been adapted to the specific characteristics of our RC material. The amount of material is adjusted based on the thickness of the eventual layer. This is done to avoid errors when only the amount of materials is used as there are pores in the layer. The reference process creates an 800 µm thick layer, materials D6 and D7 have a layer of 300 and 500 µm thick, respectively. Table 5 indicates the new amount of materials for the RC materials. The energy use is set at the reference value of 5.23 kWh for this kind of technique, based on the estimated value of Prézélus et al. [ 47 ]. Razali et al. assume waste water holding acetone in their model. This is a consequence of cleaning the membranes. Based on this information, our model assumes water and acetone are required as input, and wastewater and acetone are outgoing flows. According to Razali et al., 100–500 litre of wastewater is generated per square meter of produced membrane [ 48 ]. This wastewater holds either 7500 ppm acetone for 100 litres or 500 ppm acetone for 500 litres of wastewater. This paper assumes that 500 litres of water and wastewater are related to the process, with a concentration of 5 ppm acetone per litre of water. Converted to 1 dm 2 , this gives 5 litres of water and wastewater and 2500 mg of acetone emissions. The same amount of acetone is also assumed as input, as this is more than is needed to produce the material itself. Table 5 Modelling of the phase inversion-based method. material D6 (dm 2 ) D7 (dm 2 ) Water input (l) 5 5 Acetone input (mg) 2500 2500 Polymer (kg) 0.0003 0.0005 Energy (kWh) 0.00523 0.00523 Nitrogen (l) 0.00000210 0.00000351 Acetone output (emissions mg) 2500 2500 Wastewater output (l) 5 5 3.1.2.4 Roll to roll deposition Roll-to-roll deposition is a process where materials are transported from one process to another by rolls. Here, only the energy used for the rolls is taken into account. Other assumptions about potential processes would make the process and the output of the LCA calculation too uncertain. To reproduce the energy needed for this process, the energy used from the 'Sheet rolling, aluminium {RER}| processing | Cut-off, U' record is chosen as the density of aluminium is closest to the materials which are in the roll-to-roll process in this paper. This is once again scaled down to an energy use of 0.0000327 kWh/dm 2 . 3.1.3 Environmental impact assessment The results of the EI assessment are shown in Fig. 1 to Fig. 4 . Figure 1 shows the single score environmental impact for all impact categories. Figure 2 shows the same result but highlights the relative contribution of every impact category. Figure 3 shows the single score environmental impact for the different components of the RC materials, and Fig. 4 shows the same result, highlighting the relative contribution of the various components. The five EI categories with the highest impact, i.e. climate change (CC), acidification (AC), resource use fossils (RUF), resource use minerals and metals (RUMM) and particulate matter (PM), are coloured red. It is clear that CC and RUF are the impact categories with the most significant impact for all materials. Comparing this to Fig. 3 and Fig. 4 clarifies that this is due to the production processes, specifically the energy use during these processes. More than 75% of the SSEI of materials D1, D2, D3, D8, D9 and D10 is caused by the energy used during the sputtering process. This is because these RC materials have multiple layers of sputtered material, making the sputtering process longer and causing a more significant energy use. This is especially true for materials D2 and D3, with over 20 sputtered layers. The materials only account for less than 10% of the environmental impact of the latter two. Material D4 has only one sputtered layer and still has almost the same impact as D1, with seven sputtered layers. In D4, more silver is used than in the other materials, generating a high environmental impact. This can also be seen in Fig. 4 , where silver (Ag) is responsible for almost 30% of the EI. The use of silver also generates a high environmental impact for materials D5 and D9. The silicon wafer is used for all materials with a sputter deposition and is responsible for a relatively large share of the total SSEI of these materials. Material D5 has a double silicon wafer, which explains the higher SSEI caused by the wafer for this material. Manufacturing a silicon wafer is energy intensive, and this also explains why the ratio of the different environmental impacts is still comparable to the other materials. The spin coating process has almost no contribution to the environmental impact of this material. Only for RC materials D6 and D7, the materials are responsible for a more significant share of the impact than the energy use. Here it is clear that the metals, steel and aluminium are responsible for approximately 50% of the SSEI. The additional materials during the phase inversion process also become important. Approximately 10% of the total SSEI is caused by the use of acetone. The energy consumption during the process accounts for 25–45% of the EI. Looking at the materials manufactured using a sputtering process, it is clear that material D8 has the lowest EI caused by the materials without considering the impact of the production process. As for the other materials, only the silicon wafer causes a high impact. This is because this material is the only one not using silver in the composition. When comparing the ten materials, it is clear that material D3 has the biggest SSEI due to sputtering, with an environmental impact of 1199.4 µPt*dm − 2 ,and materials D6 and D7 have the lowest SSEI due to the absence of this sputtering technique, with an environmental impact of 3.77 and 6.03 µPt*dm − 2 respectively. Also, the materials used for these last two RC materials have a lower EI than those used in the other seven RC materials. Ultimately, when comparing RC materials to a conventional concrete roof tile, it becomes evident that all RC materials, except for D6 and D7, exhibit an environmental impact at least ten times higher. However, it is essential to note that this comparison may not be entirely conclusive, given the uncertainty whether the RC materials will serve as replacements for conventional roof tiles or be added on top of a typical roof structure. Nevertheless, it does provide an initial idea of the environmental implications of these materials in contrast to traditional roofing materials. Figure 5 and Fig. 6 show the results for climate change. Similar conclusions can be drawn: the energy use during the production processes causes the biggest share of the EI. Only for RC materials D5, D6 and D7, a significant share of the EI is caused by other aspects. For RC material D5, the relative contribution of the silicon wafer increases when only looking at climate change (compared to the SSEI). This can be explained by the high amount of energy needed to produce this layer. The ratio of impact for RC materials D6 and D7 is similar to the total single score, while for the other RC materials, the share of the materials has decreased compared to the SSEI. The results for particulate matter, acidification, resource use fossils and resource use minerals and metals are presented in the additional information: Figures S1 -S8. 3.2 Cooling potential This section presents the simulation results of the cooling potential focusing on the various heat transfer mechanisms influencing cooling power, namely solar, radiative, and convective fluxes. Figure 7 illustrates how the intrinsic characteristics of the materials impact the radiative and solar heat fluxes. It is essential to note that radiated heat depends on the emissivity of materials in the infrared wavelength and the surface temperature. Therefore, the lower the temperature is the lower the radiative losses will be. Consequently, the setup in Madrid consistently yields higher radiated values than in Brussels due to its higher surface temperature (Table 2 ); RC materials in Madrid are 4.51°C in January and 24,4°C in July compared to the 2.51°C and 17.38°C, respectively, in Brussels. The second aspect of material properties to consider is solar reflectivity, critical for achieving daytime radiative cooling. Materials D6/D7 and D10 exhibit the most favourable behaviour in both locations, achieving cooling energy values of -13.2 and − 15.9 kWh·m⁻² in Brussels and − 41.0 and − 41.1 kWh·m⁻² in Madrid during the month of July. Figure 8 presents the overall cooling performance of the materials, considering the total energy fluxes, which include solar heat gains, radiative heat losses, and convective heat gains, as discussed previously. Convection significantly influences thermal equilibrium by tending to equalize the surface temperature with the ambient temperature. It has to be noted that all the RC roofs are at sub-ambient temperatures whereas the concrete roof tile has a higher temperature than the ambient. In Brussels, there is a more significant temperature differential between the surface and the ambient air in winter compared to summer; therefore, higher convective heat gains occur in winter. When assessing the global energy balance in Brussels, all materials exhibit positive heat fluxes, meaning they heat up in summer and winter, with higher heat gains in winter due to the influence of convection. During the winter the materials with radiative cooling properties show similar total heat gains as the concrete roof tile (D10 with 21.7 kWh·m⁻² and D1 with 27.0 kWh·m⁻²). During the summer, nevertheless, the best-performing RC material consistently demonstrates superior performance (D10 with 2.9 kWh·m⁻² compared to the worst-performing D1 with 24.3 kWh·m⁻²). When considering the impact of these materials in Madrid, the best performing materials are able to effectively achieve cooling during summer; moreover, all materials experience heat gains during winter due to the low surface temperature (4.51°C) compared to the ambient temperature (7°C). During the summer, materials D6/7 and D10 exhibit the most significant heat losses, reaching − 8.4 kWh·m⁻² compared to the 15 kWh·m⁻² of the concrete tile; while during winter, they show heat gains of 7.7 and 6.5 kWh·m⁻², respectively. It can be concluded that the RC materials have a similar performance to the performance of the concrete roof tile in winter, especially in Brussels, while we see significant differences during the summer. To conclude, in determining the best-performing material, enhanced comfort during winter, reduced overcooling penalty, and greater heat losses during summer should be considered ( Table 6 ). Figure 7. Monthly accumulated radiated heat and solar gains (kWh·m -2 ) for the roof tile and materials D1 to D10 in Brussels and Madrid for January and July. Table 6 Accumulated monthly heat gains (+) or losses (-) of the selected RC materials in Brussels and Madrid: radiated heat losses, solar heat gains, convection heat gains and total value. Radiant (kWh·m − 2 ) Solar (kWh·m − 2 ) Convection (kWh·m − 2 ) Total (kWh·m − 2 ) Material Jan Jul Jan Jul Jan Jul Jan Jul Brussels Tile -8,5 -43,9 15,0 91,7 20,9 -23,2 27,4 24,6 D1 -3.7 -8.9 2.4 14.6 28.3 18.6 27.1 24.3 D2 -6.0 -17.7 0.9 5.2 28.4 18.8 23.3 6.3 D3 -5.4 -15.0 2.7 16.8 28.4 18.6 25.7 20.4 D4 -6.5 -19.3 1.5 9.4 28.4 18.7 23.5 8.9 D5 -5.9 -18.9 1.5 9.3 28.4 18.7 24.0 9.2 D6/D7 -6.3 -19.5 1.0 6.3 28.4 18.8 23.2 5.5 D8 -5.1 -16.4 1.9 11.8 28.4 18.7 25.2 14.2 D9 -5.9 -14.7 1.0 6.3 28.4 18.7 23.6 10.3 D10 -7.1 -18.2 0.4 2.3 28.4 18.8 21.7 2.9 Madrid Tile -21.9 -87.1 37.6 144.4 0.1 -32.1 15.8 25.2 D1 -5.8 -22.2 6.0 23.0 17.2 32.2 17.4 33.0 D2 -11.0 -45.0 2.1 8.2 17.3 32.6 8.4 -4.2 D3 -9.6 -38.2 6.9 26.4 17.2 32.3 14.5 20.5 D4 -12.2 -50.1 3.9 14.9 17.3 32.5 9.0 -2.7 D5 -11.8 -49.8 3.8 14.7 17.3 32.5 9.3 -2.5 D6/D7 -12.2 -50.9 2.6 9.9 17.3 32.6 7.7 -8.4 D8 -10.2 -43.0 4.9 18.7 17.3 32.4 11.9 8.0 D9 -9.5 -36.5 2.6 9.9 17.3 32.5 10.3 5.8 D10 -11.7 -44.7 0.9 3.6 17.3 32.6 6.5 -8.5 3.3 Comparative framework Figure 9 and Fig. 10 present the environmental impact of the ten RC materials and their cooling performance for the two selected months, January and July, and for the selected cities, Brussels and Madrid. As discussed in the previous section, Fig. 9 considers radiative heat losses and solar heat gains, while Fig. 10 also includes convection. The Pareto front for July is in the upper left corner of the graphs, as the lowest environmental impact and the highest cooling power are in that area. The materials that form the Pareto front are highlighted with a rectangle around their material name. The Pareto front for January is on the bottom left corner, as a low cooling performance is preferred. Figure 10 clearly shows that material D6 is the best-performing material considering both the cooling performance and environmental impact, as it is located in the Pareto front both in summer and winter. Material D1 would be a potentially good material only looking into the winter months, but its low cooling performance during summer makes it not preferable. The cooling performance during summer is seen as the most critical parameter to grade RC materials, materials D7, D4 and D5 score well compared to the database. The cooling performance is similar to material D6, only the environmental impact is significantly higher. These results, hence, hold that newly developed RC materials should be benchmarked against these best-performing materials to be competitive with the existing RC materials. The results considering the five selected environmental impact categories (global warming potential, particulate matter, acidifications, resource use fossils and resource use minerals and metals) show that the same materials are located in the pareto front for these impact categories (additional information: Figures S9-S13). In addition to assessing cooling power and environmental impact, it is crucial to consider the cost and durability of materials when evaluating their suitability for outdoor applications. The cost of materials, installation, and maintenance can significantly impact the feasibility of a cooling solution. Moreover, materials must withstand prolonged exposure to harsh outdoor conditions, including UV radiation, temperature fluctuations, moisture, and mechanical stress. Durable materials can reduce long-term maintenance and replacement costs, making them more economically and environmentally viable. Therefore, a comprehensive evaluation should balance cooling performance and environmental sustainability with cost-effectiveness and resilience to outdoor exposure, ensuring a holistic approach to outdoor cooling solutions. 4 Conclusion The selection of the existing state-of-the-art RC materials proved that collecting sufficient data to model the materials for environmental impact assessment remains challenging. Numerous data about the materials, production and performances are needed to assess the cradle-to-gate environmental impact and compare the impact related to the performance of the various RC materials being developed. Many assumptions regarding the production processes were needed due to lack of published data. In this paper, data were collected through literature and expert consultation. An uncertainty analysis will be done in a subsequent step of the research based on all the assumptions made to understand better the potential variation in the results obtained due to these uncertainties. Moreover, it is recommended that researchers in the future more transparently report the production processes and that the measurement method and indicators for the performance of RC materials become standardised. The single score environmental impact assessment indicated that the production processes, especially the sputtering process, are the biggest contributors to the environmental impact. The sputter process is responsible for more than 75% of the environmental impact for materials D1, D2, D3, D8, D9 and D10. After the impact of the production processes, the usage silver and a silicon wafer also results in a high environmental impact. Changing or choosing a different production technique can significantly lower the EI. The impact for climate change separately showed the same trend as climate change is the impact category with the most significant share of the single score environmental impact, heavily influenced by the energy use throughout the production process. The assessment concluded that two materials, D6 and D7, clearly generate a lower environmental impact, which can be explained by the absence of the sputtering process for these RC materials. Materials D6 and D7 have a single score environmental impact of 3.77 and 6.03 µPt*dm − 2 respectively, while the worst scoring material (D3) caused an impact of 1199.4 µPt*dm − 2 . Moreover, when comparatively assessing the environmental impact of RC materials, it is necessary to consider any difference in cooling performance as well. No straightforward comparison of any declared cooling performance of RC materials is currently possible based on existing literature as different methods, indicators and climatic contexts have been used for determining the cooling performance. Consequently, using the reported cooling power or temperature drops to create environmental benchmarks would be misleading. To overcome this, a validated model to calculate the performance of RC materials has been used in this paper. This allows us to present for the first time the cooling performance alongside their environmental impact, offering insight into the most suitable material considering both aspects. The analysis of the ten existing RC materials in winter and summer conditions in Brussels and Madrid indicated that D6 and D10 are the most preferred ones from an environmental and performance perspective. These materials are hence located in the pareto front with a single score environmental impact of 3.77 µPt*dm − 2 and 591.38 µPt*dm − 2 with decreased heat gains in summer of 41 kWh*m − 2 and 41.1 kWh*m − 2 for materials D6 and D10 respectively. Finally, in the next step of the research, the sensitivity of the modelling assumptions of the RC materials and the uncertainty of the data will be investigated, as this is a limitation of the current paper. Furthermore, the first mixture(s) of the PMC will be modelled and their environmental impact and performance will be assessed against the RC materials analysed in this paper. Abbreviations AC Acidification AW Atmospheric window CC Climate change EF Ecotoxicity freshwater EI Environmental Impact LCA Life Cycle Assessment MIRACLE Meta concrete with Infrared Radiative Cooling capacity for Large Energy savings PM Particulate matter PMC Photonic meta-concrete RC Radiative Cooling RUF Resource use fossils RUMM Resource use minerals and metals SSEI Single score environmental impact UHI Urban heat island Declarations Ethics approval and consent to participate Not applicable Consent for publication Not applicable Availability of data and material All data generated or analysed during this study are included in this published article and published in the additional file: Figures S1-S13 and Tables S1-S4.10. Competing interests The authors declare that they have no competing interests Funding This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 964450 Authors' contributions NA: Conceptualization, methodology environmental impact assessment and comparative framework, formal analysis environmental impact and comparative framework, Writing – original draft, visualization. LC: methodology cooling potential, formal analysis cooling potential, writing – original draft cooling potential. KA: Conceptualization, Writing – Review and Editing, Supervision. All authors read and approved the final manuscript. Acknowledgements We would like to express my gratitude to Prof. Dr. Irene Taurino (KU Leuven), prof. Dr. Alicia Torres (Public University of Navarre) and researchers from the Leuven NanoCentre for their invaluable assistance and expert guidance in modeling the thin film deposition techniques used in this research. References United nations. 68% of the world population projected to live in urban areas by 2050, says UN, https://www.un.org/development/desa/en/news/population/2018-revision-of-world-urbanization-prospects.html . Accessed 3 March 2023. Elliot T, Babí Almenar J, Rugani B (2020) Modelling the relationships between urban land cover change and local climate regulation to estimate urban heat island effect. Urban For Urban Green 50:126650. https://doi.org/10.1016/j.ufug.2020.126650 Mohajerani A, Bakaric J, Jeffrey-Bailey T (2017) The urban heat island effect, its causes, and mitigation, with reference to the thermal properties of asphalt concrete. J Environ Manage 197:522–538. https://doi.org/10.1016/j.jenvman.2017.03.095 Delmastro C, Martinez-Gordon R (2023) Tracking Space Cooling. https://www.iea.org/energy-system/buildings/space-cooling#tracking Liu J, Zhou Z, Zhang J, et al (2019) Advances and challenges in commercializing radiative cooling. Materials Today Physics 11:100161. https://doi.org/10.1016/j.mtphys.2019.100161 Santamouris M, Papadopoulos A M, Paolini R et al (2021). Cool roofs cost benefit analysis. Research Plan and Progress Report. School of Built ENVIRONMENT, UNSW Sydney, Australia. Givoni B (1976) Man, climate and architecture. applied science publishers 572 Nahar NM, Sharma P, Purohit MM (2003) Performance of different passive techniques for cooling of buildings in arid regions. Build Environ 38:109–116. https://doi.org/10.1016/S0360-1323(02)00029-X Hanif M, Mahlia TMI, Zare A, et al (2014) Potential energy savings by radiative cooling system for a building in tropical climate. Renewable and Sustainable Energy Reviews 32:642–650. https://doi.org/10.1016/j.rser.2014.01.053 Eicker U, Dalibard A (2011) Photovoltaic-thermal collectors for night radiative cooling of buildings. Solar Energy 85:1322–1335. https://doi.org/10.1016/j.solener.2011.03.015 Raman AP, Anoma MA, Zhu L, et al (2014) Passive radiative cooling below ambient air temperature under direct sunlight. Nature 515:540–544. https://doi.org/10.1038/nature13883 Zhai Y, Ma Y, David SN, et al (2017) Scalable-manufactured randomized glass-polymer hybrid metamaterial for daytime radiative cooling. Science (1979) 355:1062–1066. https://doi.org/10.1126/science.aai7899 Lim XZ (2020) The super-cool materials that send heat to space. Nature 577:18–20. https://doi.org/10.1038/d41586-019-03911-8 Carlosena L, Ruiz-Pardo Á, Feng J, et al (2020) On the energy potential of daytime radiative cooling for urban heat island mitigation. Solar Energy 208:430–444. https://doi.org/10.1016/j.solener.2020.08.015 Adams N, Allacker K (2022) Development of a Radiative Cooling Material Database to Benchmark the Environmental Impact of a newly Developed Photonic Meta-Concrete. In: SETAC Europe annual meeting 2022. p 12 Merlo A, Léonard G (2021) Magnetron sputtering vs. Electrodeposition for hard chrome coatings: A comparison of environmental and economic performances. Materials 14:. https://doi.org/10.3390/ma14143823 Tyona MD (2013) A theoritical study on spin coating technique. Advances in materials Research 2:195–208. https://doi.org/10.12989/amr.2013.2.4.195 Yadav P, Ismail N, Essalhi M, et al (2021) Assessment of the environmental impact of polymeric membrane production. J Memb Sci 622:118987. https://doi.org/10.1016/j.memsci.2020.118987 Cresko J, Shenoy D, Liddell H P H, et al (2015) Quadrennial Technology. Innovating clean energy Technologies in advanced manufacturing. Makhlouf S (2021) Life Cycle Assessment (LCA) analysis for flexible thin-film solar cells at HyEt Solar. http://resolver.tudelft.nl/uuid:738d603b-4aba-4c1a-8c 82-2b4a08c09670. Sala S, Cerutti A K, Pant R, (2018). Development of a weighting approach for the Environmental Footprint. Publications Office of the European Union: Luxembourg. https://doi.org/10.2760/446145 . Carlosena L, Ruiz-Pardo Á, Rodríguez-Jara EÁ, Santamouris M (2023) Worldwide potential of emissive materials based radiative cooling technologies to mitigate urban overheating. Build Environ 243:. https://doi.org/10.1016/j.buildenv.2023.110694 Meteonorm 7. Http://Meteonorm.Ch. Accessed 1 August 2023. Mandal J, Fu Y, Overvig AC, et al (2018) Hierarchically porous polymer coatings for highly efficient passive daytime radiative cooling. Science (1979) 362:315–319. https://doi.org/10.1126/science.aat9513 Kecebas MA, Menguc MP, Kosar A, Sendur K (2017) Passive radiative cooling design with broadband optical thin-film filters. J Quant Spectrosc Radiat Transf 198:1339–1351. https://doi.org/10.1016/j.jqsrt.2017.03.046 Rephaeli E, Raman A, Fan S (2013) Ultrabroadband photonic structures to achieve high-performance daytime radiative cooling. Nano Lett 13:1457–1461. https://doi.org/10.1021/nl4004283 Zhai Y, Ma Y, David SN, et al (2017) Scalable-manufactured randomized glass-polymer hybrid metamaterial for daytime radiative cooling. Science (1979) 355:1062–1066. https://doi.org/10.1126/science.aai7899 Kou J long, Jurado Z, Chen Z, et al (2017) Daytime Radiative Cooling Using Near-Black Infrared Emitters. ACS Photonics 4:626–630. https://doi.org/10.1021/acsphotonics.6b00991 Osuna Ruiz D, Lezaun C, Torres-García AE, Beruete M (2023) Metal-free design of a multilayered metamaterial with chirped Bragg grating for enhanced radiative cooling. Opt Express 31:22698. https://doi.org/10.1364/oe.492404 Kecebas MA, Menguc MP, Kosar A, Sendur K (2020) Spectrally selective filter design for passive radiative cooling. Journal of the Optical Society of America B 37:1173. https://doi.org/10.1364/josab.384181 Mattox M, D (2010) Handbook of Physical Vapor Deposition (PVD) Processing, Second. William Andrew Publishing EPFL. Pfeiffer SPIDER 600, https://www.epfl.ch/research/facilities/cmi/equipment/thin-films/pfeiffer-spider-600/; . Accessed 7 October 2022. Fiameni S, Battiston S, Castellani V, et al (2021) Implementing sustainability in laboratory activities: A case study on aluminum titanium nitride based thin film magnetron sputtering deposition onto commercial laminated steel. J Clean Prod 285:124869. https://doi.org/10.1016/j.jclepro.2020.124869 Merlo A, Léonard G (2022). Use of Environmental Assessment and Techno Economic Analysis (TEA) to Evaluate the Impact and Feasibility of Coatings for Manufacturing Processes. Computer Aided Chemical Engineering 49:2071–2076. Classen M, Althaus H-J, Blaser S, et al (2009) Life Cycle Inventories of Metals. Final report ecoinvent data v21 No 10 1–926. Merlo A, Léonard G (2021) Magnetron sputtering vs. Electrodeposition for hard chrome coatings: A comparison of environmental and economic performances. Materials 14:. https://doi.org/10.3390/ma14143823 O’Hanlon JF (2003) A User’s Guide to Vacuum Technology. Wiley. https://doi.org/10.1002/0471467162 . Materials Research Facilities Network. ATC-2000F AJA SPUTTERING SYSTEM, https://www.mrfn.org/instruments/nanomaterials-thin-films/atc-2000f-aja-sputtering-system . Accessed 7 October 2022. Toronto Nanofabrication Centre Quotation. Sputter deposition recipes. https://tnfc.utoronto.ca/tnfc/user-access/user-recipes/sputter-depositon-recipes/; . Accessed 7 October 2022. Explorer 14 recipes. https://www.seas.upenn.edu/~nanosop/Explorer14_Recipes.htm ; 2021. Accessed 7 October 2022. Wang Z, Wallra A, Poto£nik A, et al (2015) Development of Sputtering Process for High Quality Nb Thin Film Project supervisor: Phelma tutor Kaplan K, Kim K, Winterkorn M, et al (2016) Optimizing the Electrical Stability of Platinum Films Deposited in Lesker-Sputter Gong J, Darling SB, You F (2015) Perovskite photovoltaics: Life-cycle assessment of energy and environmental impacts. Energy Environ Sci 8:1953–1968. https://doi.org/10.1039/c5ee00615e Celik I, Song Z, Cimaroli AJ, et al (2016) Life Cycle Assessment (LCA) of perovskite PV cells projected from lab to fab. Solar Energy Materials and Solar Cells 156:157–169. https://doi.org/10.1016/j.solmat.2016.04.037 Espinosa N, Serrano-Luján L, Urbina A, Krebs FC (2015) Solution and vapour deposited lead perovskite solar cells: Ecotoxicity from a life cycle assessment perspective. Solar Energy Materials and Solar Cells 137:303–310. https://doi.org/10.1016/j.solmat.2015.02.013 García-Valverde R, Cherni JA, Urbina A (2010) Life cycle analysis of organic photovoltaic technologies. Progress in Photovoltaics: Research and Applications 18:535–558. https://doi.org/10.1002/pip.967 Prézélus F, Tiruta-Barna L, Guigui C, Remigy JC (2021) A generic process modelling – LCA approach for UF membrane fabrication: Application to cellulose acetate membranes. J Memb Sci 618:. https://doi.org/10.1016/j.memsci.2020.118594 Razali M, Kim JF, Attfield M, et al (2015) Sustainable wastewater treatment and recycling in membrane manufacturing. Green Chemistry 17:5196–5205. https://doi.org/10.1039/c5gc01937k Additional Declarations No competing interests reported. Supplementary Files Additionalfile.docx Cite Share Download PDF Status: Published Journal Publication published 08 Oct, 2024 Read the published version in Environmental Sciences Europe → Version 1 posted Editorial decision: Revision requested 10 Aug, 2024 Reviews received at journal 08 Aug, 2024 Reviews received at journal 04 Aug, 2024 Reviews received at journal 22 Jul, 2024 Reviewers agreed at journal 14 Jul, 2024 Reviewers agreed at journal 09 Jul, 2024 Reviewers agreed at journal 08 Jul, 2024 Reviewers agreed at journal 08 Jul, 2024 Reviewers invited by journal 02 Jul, 2024 Editor assigned by journal 18 Jun, 2024 Submission checks completed at journal 18 Jun, 2024 First submitted to journal 14 Jun, 2024 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-4580586","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":325210678,"identity":"cce32e33-bf95-4bed-83b0-1f718f6a4e5e","order_by":0,"name":"NICK ADAMS","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA8ElEQVRIiWNgGAWjYDACZiBkgODDDAwFMEHitLAlMzAYEKOFAa6Fx5g4LebszI8NGGqs5XX7z3w25jGwSdxwvPcAc0EFbi2WzWzGCQzH0g233cjdnMxjkJa44cy5BOYZZ3BrMTjMw3yAge0w47YbvJsP8xgcTpw5I8eAmbeNkJZ/h+23nT/zGKjlf+LM+W+AWv7h15LA2HY4cduBHGagww4k9kvwALU04NPCZmyQ2JeevO1GmrHhHINk436eHIPDM47h0XL+8GOJD9+sbbeBGG8q7GTb2M8YPi6owa0FDBLQBQ4Q0DAKRsEoGAWjgAAAAHyKTZFhTzLoAAAAAElFTkSuQmCC","orcid":"","institution":"KU Leuven","correspondingAuthor":true,"prefix":"","firstName":"NICK","middleName":"","lastName":"ADAMS","suffix":""},{"id":325210680,"identity":"137efecc-f399-4049-ac6a-f3a8a85b5b01","order_by":1,"name":"Laura Carlosena","email":"","orcid":"","institution":"Public University of Navarre (UPNA)","correspondingAuthor":false,"prefix":"","firstName":"Laura","middleName":"","lastName":"Carlosena","suffix":""},{"id":325210682,"identity":"df9a178d-cec2-482a-b16a-362e329eea48","order_by":2,"name":"karen Allacker","email":"","orcid":"","institution":"KU Leuven","correspondingAuthor":false,"prefix":"","firstName":"karen","middleName":"","lastName":"Allacker","suffix":""}],"badges":[],"createdAt":"2024-06-14 08:23:27","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4580586/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4580586/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1186/s12302-024-01005-5","type":"published","date":"2024-10-08T15:57:11+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":60191050,"identity":"d8765209-59c1-4e1b-a449-6a3b2d6af071","added_by":"auto","created_at":"2024-07-12 20:18:09","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":1070979,"visible":true,"origin":"","legend":"\u003cp\u003eSingle score environmental impact of the selected RC materials, showing the contribution of the various impact categories.\u003c/p\u003e","description":"","filename":"Figure1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4580586/v1/35f4f59aca72153f44f7e756.jpg"},{"id":60190831,"identity":"5dd9f520-78ed-4ed9-9be3-893729cc5988","added_by":"auto","created_at":"2024-07-12 20:10:09","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":2669199,"visible":true,"origin":"","legend":"\u003cp\u003eSingle score environmental impact of the selected RC materials, showing the ratio of the impact categories.\u003c/p\u003e","description":"","filename":"Figure2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4580586/v1/612184f3a39dd3ec675c9f84.jpg"},{"id":60190833,"identity":"0d54ef87-5728-4ac0-a76d-a8f959ef7c45","added_by":"auto","created_at":"2024-07-12 20:10:09","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":925405,"visible":true,"origin":"","legend":"\u003cp\u003eSingle score environmental impact of the selected RC materials, showing the contribution of the various components in the production process.\u003c/p\u003e","description":"","filename":"Figure3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4580586/v1/e772f305d8d2e85492da3da3.jpg"},{"id":60191267,"identity":"0c0bca45-69c8-4140-a267-395e8cb52473","added_by":"auto","created_at":"2024-07-12 20:26:09","extension":"jpg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":1977584,"visible":true,"origin":"","legend":"\u003cp\u003eSingle score environmental impact of the selected RC materials, showing the ratio of the various components in the production process\u003c/p\u003e","description":"","filename":"Figure4.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4580586/v1/aa6128c47f254b22d43e28dd.jpg"},{"id":60190834,"identity":"a9597628-65d2-4128-bb7a-5bcc27b2f968","added_by":"auto","created_at":"2024-07-12 20:10:09","extension":"jpg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":991075,"visible":true,"origin":"","legend":"\u003cp\u003eKg CO\u003csub\u003e2eq\u003c/sub\u003e of the selected RC materials, showing the various components of the production process.\u003c/p\u003e","description":"","filename":"Figure5.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4580586/v1/9ce1efd0121f678991e24926.jpg"},{"id":60190839,"identity":"f51a5659-46c5-483b-9794-ba590ef2ade9","added_by":"auto","created_at":"2024-07-12 20:10:10","extension":"jpg","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":2067864,"visible":true,"origin":"","legend":"\u003cp\u003eKg CO\u003csub\u003e2eq\u003c/sub\u003e of the selected RC materials, showing the ratio of the various components in the production process.\u003c/p\u003e","description":"","filename":"Figure6.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4580586/v1/43b75a0f423cac8dd44d2444.jpg"},{"id":60190837,"identity":"c406fd9a-1703-4224-bd72-5457b9e6ae59","added_by":"auto","created_at":"2024-07-12 20:10:09","extension":"jpg","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":72100,"visible":true,"origin":"","legend":"\u003cp\u003eMonthly accumulated radiated heat and solar gains (kWh·m\u003csup\u003e-2\u003c/sup\u003e) for the roof tile and materials D1 to D10 in Brussels and Madrid for January and July.\u003c/p\u003e","description":"","filename":"F7.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4580586/v1/7c66d14afa37f4713b145c83.jpg"},{"id":60191054,"identity":"7ba86e19-b64a-4fbc-b68b-55480587abfa","added_by":"auto","created_at":"2024-07-12 20:18:10","extension":"jpg","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":70551,"visible":true,"origin":"","legend":"\u003cp\u003eTotal Monthly accumulated heat (kWh·m\u003csup\u003e-2\u003c/sup\u003e) for the roof tile and materials D1 to D10 in Brussels and Madrid for January and July.\u003c/p\u003e","description":"","filename":"F8.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4580586/v1/12b7981a9b1040b31e103773.jpg"},{"id":60191051,"identity":"b5b35372-0cdd-40e4-bbc7-1f24a5dc5ecd","added_by":"auto","created_at":"2024-07-12 20:18:09","extension":"jpg","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":77649,"visible":true,"origin":"","legend":"\u003cp\u003eRelationship between accumulated radiated heat and solar gains (kWh·m\u003csup\u003e-2\u003c/sup\u003e) and environmental impact (µPt·dm\u003csup\u003e-2\u003c/sup\u003e), materials in the pareto front are highlighted with a border.\u003c/p\u003e","description":"","filename":"F9.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4580586/v1/bf4f940f1efbc379fb4dc653.jpg"},{"id":60191053,"identity":"e14aa5e4-9382-40ca-a39b-7934e665608d","added_by":"auto","created_at":"2024-07-12 20:18:09","extension":"jpg","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":75058,"visible":true,"origin":"","legend":"\u003cp\u003eRelationship between total heat (kWh·m\u003csup\u003e-2\u003c/sup\u003e) and environmental impact (µPt·dm-2), materials in the pareto front are highlighted with a border.\u003c/p\u003e","description":"","filename":"F10.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4580586/v1/8fc89f9eb358cddf2402bf3b.jpg"},{"id":66597070,"identity":"aabb596e-ce7f-4c7a-b0f3-1b0f86888442","added_by":"auto","created_at":"2024-10-14 16:06:50","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":11170912,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4580586/v1/4091e65c-1753-4c68-976b-19697b2ecb96.pdf"},{"id":60190842,"identity":"db34d0b4-8c12-452e-afe0-7fd3f49f35f8","added_by":"auto","created_at":"2024-07-12 20:10:10","extension":"docx","order_by":21,"title":"","display":"","copyAsset":false,"role":"supplement","size":2765472,"visible":true,"origin":"","legend":"","description":"","filename":"Additionalfile.docx","url":"https://assets-eu.researchsquare.com/files/rs-4580586/v1/200ae3efa69986265779529c.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Evaluating the cradle-to-gate Environmental Impact and cooling performance of Advanced Daytime Radiative Cooling Materials to Establish a Comparative Framework for a Novel Photonic Meta-Concrete","fulltext":[{"header":"1 Introduction","content":"\u003cp\u003eUrbanisation is a phenomenon which explains the increase of people living in towns and cities. By the end of 2050, it is expected that 68% of the world's population will be living in urban areas [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. A higher density of people living in cities generates more anthropogenic heat production, reduced vegetation and evapotranspiration, and less permeable surfaces, as 60% of cities are constructed out of complex human-made heat absorbing materials [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. These factors are well known to be the drivers of the urban heat island (UHI). This effect holds that the temperature of an urban area is higher than the temperature of an adjacent rural area. The consequences of the UHI can be a higher energy demand for cooling, a significant increase in the peak energy demand, the degradation of air quality, an increased thermal stress on residents, the degradation of the urban ecosystem and a higher mortality rate due to the excessive heat [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe UHIs also have an impact outside the boundaries of cities. The International Energy Association (IEA) claims that energy consumption, and the related CO\u003csub\u003e2\u003c/sub\u003e emissions, for space cooling has tripled since 1990, which causes even more greenhouse gas emissions and implications for the electricity grids [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Next to that, cooling also leads to the emission of non-CO\u003csub\u003e2\u003c/sub\u003e greenhouse gasses caused by the leaking of refrigerants, which have a global warming potential of up to thousands of times higher than CO\u003csub\u003e2\u003c/sub\u003e.\u003c/p\u003e \u003cp\u003eMitigation strategies to fight climate change, specifically the UHI, are numerous and have been intensively studied over the past decades. One of the potential mitigation strategies is radiative cooling (RC) materials. RC materials have specific altered photonic properties, making them reflect solar irradiance and emit heat. Using such materials in cities hence allows cities to accumulate less heat from solar irradiance and emit more heat. Therefore, besides reducing energy consumption due to reduced cooling demand, these materials also help mitigating global warming [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. The most common application of these materials is roof covering, as the roof is the component with the highest temperature fluctuations [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e] and has a high sky view factor. Solar irradiation, the loss of heat in the infrared during the night and rain all affect the roof more than other building components [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Nahar et al. claimed that a roof can contribute up to 50% of the thermal load for buildings in hot climates [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eRadiation is a phenomenon where energy is transmitted in the form of electromagnetic waves due to the change in the atomic or molecular configuration of an object. For heat transfer, thermal radiation refers to the energy transmitted by an object to its surroundings because of the temperature difference between the object and its surroundings [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Radiative cooling is the natural process by which an object emits thermal energy through infrared radiation. Materials designed for daytime radiative cooling can attain sub-ambient temperatures owing to their high solar reflectivity and elevated infrared emissivity. Within the mid-infrared spectrum, specifically in the range of 8 to 13 \u0026micro;m, the Earth's atmosphere allows electromagnetic radiation to pass through without obstruction. This holds that a material can consistently keep dumping heat to stay colder than the surrounding air [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eRC materials can be used as passive and active RC materials. The latter describes implementations where the RC material assists an active cooling technology [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. In a passive application (focus of this study), the materials are not coupled with any installation and work autonomously. Due to their high solar reflectivity, daytime RC materials have a cooling power throughout the entire cycle of the day instead of only during the night. This is important as the peak cooling demand occurs during the day [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. The heating up of the surface is, hence, the biggest challenge for daytime RC materials and therefore, a high solar reflectivity is needed to guarantee that the surface temperature stays below the ambient temperature. To remain at ambient temperature, over 94% of incident short wave radiation must be reflected, especially given variations in atmospheric conditions across different geographic regions [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Zhai et al. claim that the absorbance of just a few per cent already reduces the cooling power and effectively heats the surface [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. Liu et al. came to the same conclusion as they stated that solar absorption is the critical factor for daytime RC instead of mid-infrared emissions. They argue that to break through the day and night restriction and achieve all-day RC, high mid-infrared emissions and low solar absorption must be achieved simultaneously [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Next to the challenge of absorbing less heat due to solar irradiance, another big challenge comes along with the design and application of the materials, as most surfaces in contact with the RC material will themselves heat up when exposed to solar radiation and transfer this excessive heat to the RC material [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. The Horizon 2020 project MIRACLE (Meta concrete with Infrared Radiative Cooling capacity for Large Energy savings) aims at developing a new passive daytime RC material based on conventional concrete. Using concrete gives advantages from a design perspective as the bulky solution gives more design freedom, but also from a knowledge perspective as concrete is the most used material by mankind.\u003c/p\u003e \u003cp\u003eAlthough using these RC materials sounds promising, some researchers doubt their application. Lim discusses that only a small sample of tests have been carried out to evaluate the effect of RC materials [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. There are doubts about the materials' ability to perform well in various climates and places. Lim also highlights that it is unknown whether the consumer will embrace the idea and that the effect of the RC materials might also increase the heating cost during colder periods/seasons [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. Liu et al. add the high cost of creating these materials as a problem [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Existing RC materials are moreover made of heavy metals and polymers and are produced using thin film deposition techniques characterised by high energy use and environmental impact.\u003c/p\u003e \u003cp\u003eDespite the uncertainties regarding RC materials, daytime RC systems are expected to be the number one building technology in four or five years [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. Previous research highlighted that the amount of electricity used in a building for cooling is predicted to decrease by 21% when the roof is covered with RC materials in Las Vegas, Nevada [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. A preliminary analysis indicates that RC materials could compete favourably economically against other rooftop renewable energy options for cooling, such as photovoltaic panels, but may also work cooperatively with them [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIn order to fully understand the potential of RC materials, insight in their cooling capacity is necessary. There is however no standard yet indicating how the performance of RC materials should be measured. In literature, the performance indicators \u0026lsquo;cooling power drop\u0026rsquo; and \u0026lsquo;ambient temperature drop\u0026rsquo; are used, but a significant variation is identified in how these are measured. Both average and maximum values are found in literature, and the wavelength is not always specified, which makes it impossible to compare the performance of the materials [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Moreover, experiments are carried out in specific climate and weather conditions, not providing any information on their performance under different conditions. There is hence a need for a standard method to evaluate and compare the cooling performance of RC materials. Carlosena et al. [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e] however recently proposed for the first time a method to compare the performance of RC materials under the same conditions. Carlosena et al. propose spectral emissivity to characterise the performance of multiple RC materials under the same weather conditions. This method is used in this paper to assess the performance of various RC materials.\u003c/p\u003e \u003cp\u003eAs mentioned in literature, RC materials are typically made of heavy metals using thin film deposition techniques, potentially causing a high environmental impact. In order to select the preferred RC material, hence not only the performance should be known, but also its environmental impact. No studies have however been performed on the environmental impact of RC materials. This is the second focus of this paper. More specifically, in order to better understand how the various RC materials on the market perform in terms of cooling capacity in relation to their environmental impact a comparative framework is developed. This framework can be used during the development of the new PMC, and for any other innovative RC material in future.\u003c/p\u003e"},{"header":"2 Methodology","content":"\u003cp\u003eTo assess the performance in terms of environmental impact and cooling capacity of the newly developed PMC and compare it with existing RC materials, first a selection of existing RC materials is made. Secondly, the environmental impact (EI) is assessed for 1 dm\u0026sup2; of each RC material selected, as this is the area that can be manufactured using the production techniques described below. A cradle-to-gate environmental impact assessment is performed: the system boundaries only contain the materials and production processes until the finished product. No cleaning, maintenance, labour or transport is taken into account. Thirdly, the cooling performance of each material under identical conditions in two different locations is assessed. Finally, the EI is compared with the cooling performances to identify the preferred RC material for each location.\u003c/p\u003e \u003cp\u003eTo complete the comparison, a conventional concrete roof tile is considered for both the EI assessment and the evaluation of cooling performance. This tile represents common practice in roof finishing, providing an initial indication of the competitiveness of these new materials against existing options. The modelling and EI assessment of the RC materials is performed in two steps. Firstly, the materials are selected based on predefined criteria and secondly, the materials and their production processes are modelled and the single score environmental impact (SSEI) is assessed.\u003c/p\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1 Radiative Cooling material selection\u003c/h2\u003e \u003cp\u003ePassive daytime RC materials are selected from state-of-the-art cooling materials described in scientific papers in the field. All materials identified in the literature study were considered, but only those for which sufficient data was available for the EI assessment were selected for analysis. The data required for the EI assessment are, amongst others, the amount of material, the production processes, the net cooling power and the photonic properties. The sources for the data collection were literature, including contact with the authors of the publications of the selected RC materials and experts in the field (see acknowledgements). The literature study resulted in nineteen RC materials, only ten daytime RC materials were selected to model for the database due to the lack of data for the others.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2 Modelling and environmental impact assessment of radiative cooling materials\u003c/h2\u003e \u003cdiv id=\"Sec5\" class=\"Section3\"\u003e \u003ch2\u003e2.2.1 Modelling\u003c/h2\u003e \u003cp\u003eThe selected RC materials are modelled using the generic Ecoinvent v3.6 life cycle inventory database. European data records are used if available, and global records are used if there is no other option. If multiple records are available, the decision is made based on information and requirements of the production process and experts' feedback.\u003c/p\u003e \u003cp\u003eThe ten selected RC materials are manufactured by various thin film deposition techniques, such as sputter deposition, ion beam deposition, electron beam deposition, spin coating, phase inversion and roll-to-roll deposition. Information on each of these techniques is searched in literature and by consulting experts. This mainly involves the amount of material needed, the efficiency of the process, the energy use and potential emissions. The processes are briefly described in the subsequent paragraphs.\u003c/p\u003e \u003cdiv id=\"Sec6\" class=\"Section4\"\u003e \u003ch2\u003e2.2.2.1 Sputter deposition\u003c/h2\u003e \u003cp\u003eSputter deposition, or shortly sputtering, takes place in a vacuum system where a target, the source material that will be deposited, and a substrate, where the source material will be deposited upon, are placed. Argon gas is inserted into the chamber, and a high negative voltage is applied onto this target. This high negative voltage will strip an electron from the argon gas and ionises the argon atoms. The negatively charged target then attracts these positive ions and will gain enough speed to knock off source materials. These atoms will fly off in all directions, including toward the substrate. Multiple variables need to be taken into account to model this process: the amount of material, the amount of energy, the gas to fill the vacuum chamber, the time of deposition, the kind of material that is being deposited and the substrate. Eight of the ten daytime RC materials are produced using a sputtering process. Previous research clearly indicated that sputtering processes are poorly represented in the generic Ecoinvent v3.6 database [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. A sputtering process is, therefore, modelled in this research.\u003c/p\u003e \u003cp\u003e \u003cem\u003eIon beam deposition\u003c/em\u003e and \u003cem\u003eelectron beam evaporation\u003c/em\u003e belong to the same group of thin film deposition techniques as sputter deposition. Therefore, these processes are modelled as sputter deposition processes (recommendation of experts), as ion beam deposition and electron beam evaporation are not or poorly represented in the generic Ecoinvent database. The sputtering process is expected to be a good proxy, as the vacuum system and energy consumption, which generate the highest environmental impact [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e], are similar for all three processes.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section4\"\u003e \u003ch2\u003e2.2.2.2 Spin coating deposition\u003c/h2\u003e \u003cp\u003eSpin coating is a thin film deposition technique that applies uniform thin films to flat substrates. The process typically involves depositing a small puddle of a fluid onto the centre of a substrate and then spinning the substrate at high speed to create the thin film. The typical speed is around 3000 rpm [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. Only one selected RC material is manufactured using spin coating. The spin coating process is unavailable in the Ecoinvent v3.6 database and has been modelled in this research.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section4\"\u003e \u003ch2\u003e2.2.2.3 Phase inversion methods\u003c/h2\u003e \u003cp\u003ePhase inversion is a method where polymer transformation occurs from a liquid phase to a solid phase. The first step is to prepare a homogenous polymer solution by dissolving the polymer in a solvent. By using an external or internal factor, the phase inversion is induced. External factor methods are nonsolvent-induced precipitation, precipitation from the vapour phase, and thermally-induced phase separation. The main internal factor method is evaporation-induced phase inversion [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. Two of the ten selected materials are manufactured using a phase inversion method. The Ecoinvent database does not include a phase inversion method; hence, this technique has been modelled in this research.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section4\"\u003e \u003ch2\u003e2.2.2.4 Roll to roll deposition\u003c/h2\u003e \u003cp\u003eRoll-to-roll processing is a class of substrate-based manufacturing processes in which additive and subtractive processes are used to build structures continuously [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. The production process consists of numerous processing chambers with stable conditions, in which the substrate is transported continuously from one chamber to the next to go through different thin film deposition processes, amongst others, sputter deposition [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. One of the selected materials is manufactured using roll-to-roll deposition. It is important to note that this roll-to-roll deposition technique is already a technology at the industrial scale, while the other deposition techniques are still at lab-scale. It might, hence be that the impact of the other techniques is overestimated compared to this one. This roll to roll deposition process is again not available in the Ecoinvent database and has been modelled in this research.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec10\" class=\"Section3\"\u003e \u003ch2\u003e2.2.3 Environmental impact assessment\u003c/h2\u003e \u003cp\u003eThe materials and their production processes mentioned above are modelled in the Simapro software. The final input of the materials modelled is presented in the additional file: Table \u003cspan refid=\"MOESM1\" class=\"InternalRef\"\u003eS1\u003c/span\u003e. The cradle-to-gate environmental impact of the ten RC materials is assessed using the impact categories of the EN15804\u0026thinsp;+\u0026thinsp;A2 standard; these categories are summarised in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. More specifically, a single score environmental impact is studied in detail to enable a comparison in case of contradictory indicators. This single score is calculated using the EC PEF method normalisation and weighting factors [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e], also presented in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. We acknowledge the inherent subjectivity in the weighting of environmental indicators. Therefore, we provide the results for each impact category separately in the additional file for transparency (Tables S4.1-S4.10 and Figures \u003cspan refid=\"MOESM1\" class=\"InternalRef\"\u003eS1\u003c/span\u003e-S8).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eEnvironmental impact categories of the EN15804\u0026thinsp;+\u0026thinsp;A2 standard\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eImpact category\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eUnit\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eNormalisation factor\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eWeighting factor\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eClimate change\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ekg CO2 eq\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.0001235\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.2106\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOzone depletion\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ekg CFC11 eq\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e18.64\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.0631\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIonising radiation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ekBq U-235 eq\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.0002370\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.0501\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePhotochemical ozone formation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ekg NMVOC eq\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.02463\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.0478\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eParticulate matter\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDisease inc.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1680\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.0896\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHuman toxicity, non-cancer\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCTUh\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4354\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.0184\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHuman toxicity, cancer\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCTUh\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e59173\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.0213\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAcidification\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003emol H\u0026thinsp;+\u0026thinsp;eq\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.018\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.062\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEutrophication, freshwater\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ekg P eq\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.6223\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.028\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEutrophication, marine\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ekg N eq\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.05116\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.0296\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEutrophication, terrestrial\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMol N eq\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.005658\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.0371\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEcotoxicity, freshwater,\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCTUe\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.00002343\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.0192\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLand use\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePt\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.000001220\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.0794\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eResource use, fossils\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMJ\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.00001538\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.0832\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003e2.3 Cooling Potential\u003c/h2\u003e \u003cp\u003eTo effectively compare the environmental impact of the newly developed PMC with existing RC materials, it is imperative to account for their cooling performance. Cooling performance is typically quantified regarding cooling power, expressed in watts per square meter (W\u0026middot;m\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e) or as a temperature differential relative to the ambient temperature. The literature review revealed that the method used to determine the cooling performance for the selected RC materials varies, utilising both theoretical and experimental methods and accounting for different atmospheric and climatic conditions. As a result, the cooling power or temperature drops reported in literature cannot be used to compare the various RC materials or for benchmarking purposes.\u003c/p\u003e \u003cp\u003eIn order to facilitate a meaningful cooling performance comparison among the RC materials, this paper determines the cooling performance in an identical way under the same climatic conditions for each RC material using the approach and thermal model proposed by Carlosena et al. [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. The recent study on the worldwide potential of RC materials by Carlosena et al. [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e] introduced RC materials on top of a conductive surface with a given temperature to represent the comfort temperature inside a building during a cooling or heating period. The monthly accumulated heat gains and losses are calculated to determine the cooling potential of the materials. As output, the model presents the monthly accumulated energy exchanged (kWh\u0026middot;m\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e) by the surface to its surroundings. A negative energy exchange holds net cooling of the surface and, therefore, radiative cooling.\u003c/p\u003e \u003cp\u003eThe model of Carlosena et al. was used in this paper fed with the following information: spectral emissivity, weather data of each location, and surface temperature of the conductive surface. First, the spectral emissivity of the RC materials (presented in the additional file: Table S2) was provided to the model as the average emissivity in 39 unique wavebands, which cover the entire spectrum. Secondly, two cities with temperate climate conditions were chosen: Brussels (Belgium) and Madrid (Spain). The weather data of each location including temperature, relative humidity, solar radiation, sky cover, and wind speed were used to calculate the materials' cooling potential. The climates of the selected cities were obtained from Meteonorm [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e] as TMY2 files. The months of January and July were selected as they represent a winter and summer scenario. Finally, to calculate the temperature of the conductive surface, the geometry of the KUBIK test building (Tecnalia, Bilbao) is used and is modelled as a non-insulated concrete building with a heating and cooling installation. It is assumed that the RC material is put on the flat roof, hence the monthly average outdoor roof surface temperature was calculated using EnergyPlus. The building is only heated in January with a minimum temperature of 21\u0026deg;C and cooled in July with a maximum temperature of 25\u0026deg;C. The heating and cooling system works from 7:00 until 23:00 for both months. A realistic cooling and heating pattern is assumed by using this setup. The standard concrete roof slab from the EnergyPlus database is used to represent the surface temperature of the concrete roof tile. From this point on, the temperature of this concrete slab will be presented as the temperature of the concrete roof tile. Similarly, a standard concrete roof slab covered with an RC material is used to represent the surface temperature of the RC materials. The albedo and emissivity considered for the concrete roof were 0.65 and 0.9, respectively, which are the same values as for a concrete roof tile. For the RC materials, the albedo and emissivity were 0.85 and 0.95, respectively. These latter values align with the photonic properties of the selected materials. The resulting temperatures for the concrete roof tile are higher, as this material has a lower reflectivity and a slightly lower emissivity. The utilised temperatures for the validated heat transfer model [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e] are presented in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. For the RC materials, the temperatures were 2.51\u0026deg;C in Brussels and 4.5\u0026deg;C in Madrid in winter; and. 17.38\u0026deg;C in Brussels and 24.10\u0026deg;C in Madrid in summer. Comparing the average roof surface temperature for the concrete roof tile and the cooling materials shows a decrease in temperature up to 6\u0026deg;C and 8\u0026deg;C for Brussels and Madrid respectively.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eMonthly average roof surface temperature calculated for the conductive surface for an average RC material and a concrete roof tile in Brussels and Madrid.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003eMonthly average roof surface temperature (\u0026deg;C)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eJanuary\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eJuly\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e\u003cb\u003eBrussels\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eConcrete tile\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e3.30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e23.79\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRC materials\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e2.51\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e17.38\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e\u003cb\u003eMadrid\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eConcrete tile\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e7.54\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e32.99\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRC materials\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e4.51\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e24.10\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003e2.4. Comparative framework\u003c/h2\u003e \u003cp\u003eFinally, the environmental impact of the RC materials and the concrete roof tile, calculated in section \u003cspan refid=\"Sec4\" class=\"InternalRef\"\u003e2.2\u003c/span\u003e, and their cooling performance, calculated in section \u003cspan refid=\"Sec11\" class=\"InternalRef\"\u003e2.3\u003c/span\u003e, are combined. A Pareto front is used to determine the optimal materials for two months and the selected cities. The Pareto front method enables us to identify materials that strike an optimal balance without compromising one parameter for the sake of the other. During the summer months, the preferred material exhibits a commendable combination of low environmental impact and high cooling performance. This equilibrium is aligned with the seasonal demand for effective cooling solutions, emphasising sustainability and energy efficiency during warm periods. In contrast, the winter season necessitates a distinct strategy. Here, the focus shifts towards minimising cooling performance to mitigate the heating penalty attributed to cooling materials. This approach reflects the evolving heating and cooling requirements across seasons and underscores the importance of adaptability in addressing environmental concerns. The pareto front considering the environmental impact in the five selected impact categories is presented in the additional information: Figures S9-S13.\u003c/p\u003e \u003c/div\u003e"},{"header":"3 Results","content":"\u003cdiv id=\"Sec14\" class=\"Section2\"\u003e \u003ch2\u003e3.1 Modelling and environmental impact assessment of radiative cooling materials\u003c/h2\u003e \u003cdiv id=\"Sec15\" class=\"Section3\"\u003e \u003ch2\u003e3.1.1 Radiative cooling material selection\u003c/h2\u003e \u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e shows the ten daytime RC materials considered. In the first column, the name used in this paper is mentioned, followed by the number of layers, the deposited materials, the thickness of each layer and the production process of each layer. The production process is not given for every layer, but the materials are still considered for the modelling and the environmental impact. It is, hence, necessary to assume a production process based on the characteristics of the layer. The assumptions are made based on the thicknesses or best guesses. Material D2, for example, has stacked layers with thicknesses in the magnitude of nanometres. It can, therefore, be assumed that a thin film deposition technique like sputtering is used. Material D6 and D7 are based on the paper of Mandal et al. As they discuss multiple materials to create an RC material, a worst-case (D7) and best-case (D6) scenario are chosen based on the environmental impact of the materials [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eSelected passive daytime radiative cooling materials.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"7\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eName\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"5\" nameend=\"c6\" namest=\"c2\"\u003e \u003cp\u003ecomposition\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003esource\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003e# layers\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMaterial\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eThickness of each layer\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eProcess\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eModelled process\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003eD1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eTiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e20\u0026ndash;300 nm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eElectron beam evaporation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eSputter deposition\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e20\u0026ndash;300 nm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eElectron beam evaporation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eSputter deposition\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eAg\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e50 nm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e/\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eSputter deposition\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSi-wafer\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e/\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e/\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e/\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003eD2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e31\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eTiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e20\u0026ndash;220 nm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e/\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eSputter deposition\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e31\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e50\u0026ndash;401 nm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e/\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eSputter deposition\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eAg\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e100 nm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e/\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eSputter deposition\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSi-wafer\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e/\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e/\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e/\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"4\" rowspan=\"5\"\u003e \u003cp\u003eD3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eQuartz\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2500 nm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eRoll-to-roll\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eSheet rolling (only energy use)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\" morerows=\"4\" rowspan=\"5\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSiC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e8000 nm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eRoll-to-roll\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eSheet rolling (only energy use)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eTiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e25\u0026ndash;75 nm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e/\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eSputter deposition\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMgF\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e35\u0026ndash;105 nm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e/\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eSputter deposition\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eAg\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e50 nm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e/\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eSputter deposition\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eD4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eTPX with 6% SiO\u003csub\u003e2\u003c/sub\u003e spheres\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2500 nm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eSheet rolling\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eSheet rolling\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eAg\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e200 nm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eElectron beam evaporation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eSputter deposition\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003eD5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePDMS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e100 \u0026micro;m\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eSpin coating\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eSpin coating\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSi-wafer\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e500 \u0026micro;m\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e/\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e/\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003esilver\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e120 nm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eElectron beam evaporation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eSputter deposition\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eD6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePET\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e300 \u0026micro;m\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003ePhase inversion method\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003ePhase inversion method\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSteel\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e100 \u0026micro;m\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e/\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eSheet rolling\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eD7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePolyvinyl fluoride\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e500 \u0026micro;m\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003ePhase inversion method\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003ePhase inversion method\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eAl\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e200 \u0026micro;m\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e/\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eSheet rolling\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003eD8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e113\u0026ndash;462 nm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eElectron beam evaporation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eSputter deposition\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSi\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e20\u0026ndash;97 nm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eElectron beam evaporation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eSputter deposition\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSi-wafer\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e500 \u0026micro;m\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e/\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e/\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"4\" rowspan=\"5\"\u003e \u003cp\u003eD9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e54\u0026ndash;230 nm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eElectron beam evaporation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eSputter deposition\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\" morerows=\"4\" rowspan=\"5\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eTiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e34\u0026ndash;485 nm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eElectron beam evaporation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eSputter deposition\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eTi\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e20 nm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eElectron beam evaporation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eSputter deposition\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eAg\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e200 nm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eElectron beam evaporation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eSputter deposition\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSi-wafer\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e750 \u0026micro;m\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e/\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e/\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003eD10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e314\u0026ndash;951 nm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eElectron beam evaporation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eSputter deposition\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eTiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e378\u0026ndash;782 nm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eElectron beam evaporation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eSputter deposition\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eAg\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e100 nm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eElectron beam evaporation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eSputter deposition\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSi-wafer\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e/\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e/\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e/\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec16\" class=\"Section3\"\u003e \u003ch2\u003e3.1.2 Modelling\u003c/h2\u003e \u003cp\u003eThe different thin film deposition techniques have first been modelled individually. The amount of materials and the specific data records for the raw materials are chosen based on the collected information.\u003c/p\u003e \u003cdiv id=\"Sec17\" class=\"Section4\"\u003e \u003ch2\u003e3.1.2.1 Sputter deposition\u003c/h2\u003e \u003cp\u003eSputtering is a thin film deposition technique in the same category as thermal evaporation and ion beam evaporation. As these processes are comparable and all the RC materials can be deposited by either one of them, only the sputtering deposition is modelled and applied to all thin films in the database. Moreover, the Leuven NanoCentre uses sputtering and could provide detailed information on the process. After checking the characteristics of the layers with unknown production processes for RC materials D1, D2 and D3, sputter deposition is also assumed for these layers. These thin layers will probably be manufactured by one of the above-mentioned techniques.\u003c/p\u003e \u003cp\u003eEach step in the complex sputtering process has first been modelled separately. The amount of material, substrate, number of depositions in one process, the amount of argon gas and energy used during the deposition are described in the subsequent paragraphs.\u003c/p\u003e \u003cp\u003e \u003cspan type=\"ItalicUnderline\" class=\"ItalicUnderline\" name=\"Emphasis\"\u003eMaterials\u003c/span\u003e The sputter efficiency is assumed to be 50% by recommendation of experts and as mentioned by Mattox (2010) [\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]. The amount of material for each layer is calculated by dividing the density of the materials by the volume of the layer. This is then doubled because of the 50% efficiency. Either virgin metals or metal oxides can be used as target material. Virgin metals are used in this research (recommendation of experts).\u003c/p\u003e \u003cp\u003e \u003cspan type=\"ItalicUnderline\" class=\"ItalicUnderline\" name=\"Emphasis\"\u003eSubstrate\u003c/span\u003e During a sputtering process, the target material must always be deposited on top of an already existing layer, the substrate. These substrates can be removed afterwards only to have the deposited materials. The RC materials presented here are deposited on top of a silicon wafer, as this contributes to the performance of the RC materials. Four of the seven RC materials manufactured using a thin film deposition technique already mention this silicon wafer as a substrate. This wafer is also added to the other three materials. The thickness of this wafer is assumed to be 240 \u0026micro;m as this is the standard thickness of the silicon wafer in the Ecoinvent database.\u003c/p\u003e \u003cp\u003e \u003cspan type=\"ItalicUnderline\" class=\"ItalicUnderline\" name=\"Emphasis\"\u003eNumber of depositions in one process\u003c/span\u003e The sputtering record in the Ecoinvent v3.6 database is based on rough estimations and data provided by a German manufacturer; the specific sputtering machine is unknown. The record describes that a new process needs to be accounted for every new deposited layer. However, according to the Leuven NanoCentre, up to three different materials can be deposited in alternating layers during one process. Other existing sputtering machines, like the spider 6000 [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e] and existing research on sputtering [\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e] confirm that multiple materials can be deposited in alternating layers in a single deposition process. In this paper, a single deposition process is hence accounted for every RC material.\u003c/p\u003e \u003cp\u003e \u003cspan type=\"ItalicUnderline\" class=\"ItalicUnderline\" name=\"Emphasis\"\u003eArgon gas\u003c/span\u003e Gas is inserted during the sputter deposition to create a plasma and knock off target materials. Argon is used because it is inert and does not react with other materials. Although the rate of inserted argon gas is target material dependent, a single value for the rate of inserted argon gas for all materials is considered. This is assumed to be an acceptable simplification as the contribution to the environmental impact of sputtering by the use of argon gas is negligible [\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e]. An average rate of 50 cc/min is used during deposition, according to the experts. This amount is assumed in our model, as indicated in Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e. The same amount of argon gas is assumed as emissions (recommendation of experts).\u003c/p\u003e \u003cp\u003e \u003cspan type=\"ItalicUnderline\" class=\"ItalicUnderline\" name=\"Emphasis\"\u003eEnergy use during deposition\u003c/span\u003e The Ecoinvent record 'Selective coat, copper sheet, sputter deposition {DE}| selective coating, copper sheet, sputtering | Cut-off, U' accounts for 3.47 kWh per deposition process [\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e]. As this amount of energy use is very uncertain, a detailed calculation of the energy use based on the process details has been made as described in the subsequent paragraphs.\u003c/p\u003e \u003cp\u003eA sputtering process exists in three phases. First, a vacuum is created in the chamber by using pumps. These pumps hold the chamber in vacuum during the deposition. This is further called the \"energy use of the pumps\". Secondly, energy is needed to heat the target during the deposition. Sputtering yields can be used to calculate the amount of energy needed to make a deposition of a certain thickness; these yields are used to estimate the energy demand. This process is further called \"the energy use of the target\". Finally, the substrate and the machines need to cool down. This is further referred to as \"the energy use for cooling\".\u003c/p\u003e \u003cp\u003eMerlo et al. assume a power of the pumps of 4 to 8 kW[\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e] [\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e], by considering the combination of a mechanical rotary vane pump and a turbomolecular pump. Fiameni et al. account for 10 kWh for this pumping energy[\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e] without mentioning the time required for the deposition, making it impossible to use this information to estimate the energy use for the pumps. In this paper, a pumping power of 4 kW is assumed. To pump the chamber to vacuum, a conservative time of 45 minutes is assumed [\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e], confirmed by the experts, resulting in an energy use of 3 kWh. Furthermore, the deposition time is estimated to calculate the total energy use of the pump (see next paragraph).\u003c/p\u003e \u003cp\u003eThe estimation of the energy use for the target is complex. Every material and sputtering machine has different sputtering rates. Therefore, it is not feasible to choose a specific rate for every material and every sputtering machine. The rates mentioned for four sputtering machines [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan additionalcitationids=\"CR20\" citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e] [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e][\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e] [\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e] [\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e] and two papers [\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e] [\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e] are gathered and the average is calculated. This results in a sputtering rate of 0.406 nm/s with a power of 435.83 W. This is in line with the data from the Leuven NanoCetre, specifically an average of 0.55 nm/s with a power of 100-200W. This average rate is assumed in this paper for every material. The total sputtering time is estimated by dividing the thickness of the material by the rate. This sputtering time (in seconds) is then used to calculate the energy used for the target heating and for the pump to keep the room vacuumed during sputtering.\u003c/p\u003e \u003cp\u003eFinally, the energy used for the cooling down of the process is estimated. Merlo et al. assume 20 min and a power of 2 kW for the cooling down of the material, resulting in a total power of 0.67 kWh [\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e]. Fiameni et al. assume 0.3 kWh for the cooling down [\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e]. This paper assumes that 0.3 kWh is required for cooling as the thickness of the deposited layers in the study of Fiameni et al. is closer to the thickness of the layers of the selected RC materials.\u003c/p\u003e \u003cp\u003eThe amount of gas, time and energy needed for the different materials are summarised in Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e. The calculation of all the needed variables to model the sputtering process are presented in the additional file: Table S3.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eModelling of the sputter deposition process.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"7\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMaterial\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTotal sputter thickness (nm)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eDeposition time (s)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eTarget Energy (kWh)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003ePumping time (s)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003ePumping Energy (kWh)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eAmount of Argon gas (cc)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eD1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1030\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e2537.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.307\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e5236.95\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e5.819\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e2114.12\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eD2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e10224\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e25182.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e3.049\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e27882.27\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e30.980\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e20985.22\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eD3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e12350\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e30419.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e3.684\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e33118.72\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e36.799\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e25348.93\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eD4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e200\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e492.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.060\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e3192.61\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e3.547\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e410.51\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eD5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e120\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e296.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.036\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e2995.57\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e3.328\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e246.31\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eD8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e3813\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e9391.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1.137\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e12091.63\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e13.435\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e7826.36\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eD9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1777\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e4376.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.530\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e7076.85\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e7.863\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e3647.37\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eD10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e5103\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e12569.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1.522\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e15268.97\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e16.966\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e10474.14\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec18\" class=\"Section4\"\u003e \u003ch2\u003e3.1.2.2 Spin coating deposition\u003c/h2\u003e \u003cp\u003eMaterial D5 is the only material where spin coating (in addition to the sputtering step) is used to create one of the thin film layers. Literature indicates that the material efficiency of a spin coating process is low, mentioning material losses between 70% [\u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e] and 90% [\u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e] [\u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e45\u003c/span\u003e]. A material loss of 80% is assumed in this paper. This means that five times more material is required than needed for the desired layer thickness. Several energy uses were found for spin coating. Gong et al. mention 0.22 kWh/m\u003csup\u003e2\u003c/sup\u003e, 0.51 kWh/m\u003csup\u003e2\u003c/sup\u003e and 0.08 kWh/m\u003csup\u003e2\u003c/sup\u003e [\u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e]; Espinosa et al. mention 0.5 kWh/m\u003csup\u003e2\u003c/sup\u003e and 99 kWh/m\u003csup\u003e2\u003c/sup\u003e [\u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e45\u003c/span\u003e] and Garcia-Valverde et al. mention 0.505 kWh/m\u003csup\u003e2\u003c/sup\u003e [\u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e46\u003c/span\u003e]. The median is chosen to balance out the outlier of 99 kWh/m2, resulting in 0.36 kWh/m\u003csup\u003e2\u003c/sup\u003e. As the functional unit is 1 dm\u003csup\u003e2\u003c/sup\u003e, the energy use of 0.0036 kWh/dm\u003csup\u003e2\u003c/sup\u003e is assumed. No information has been found on process emissions in the literature, and no information on these was available from experts in the field. Process emissions have hence not been taken into account.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec19\" class=\"Section4\"\u003e \u003ch2\u003e3.1.2.3 Phase inversion methods\u003c/h2\u003e \u003cp\u003eYadav et al. discuss the environmental impact assessment of a phase inversion method [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. The information they provided is used as a base for our model but has been adapted to the specific characteristics of our RC material. The amount of material is adjusted based on the thickness of the eventual layer. This is done to avoid errors when only the amount of materials is used as there are pores in the layer. The reference process creates an 800 \u0026micro;m thick layer, materials D6 and D7 have a layer of 300 and 500 \u0026micro;m thick, respectively. Table\u0026nbsp;\u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e5\u003c/span\u003e indicates the new amount of materials for the RC materials. The energy use is set at the reference value of 5.23 kWh for this kind of technique, based on the estimated value of Pr\u0026eacute;z\u0026eacute;lus et al. [\u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e47\u003c/span\u003e]. Razali et al. assume waste water holding acetone in their model. This is a consequence of cleaning the membranes. Based on this information, our model assumes water and acetone are required as input, and wastewater and acetone are outgoing flows. According to Razali et al., 100\u0026ndash;500 litre of wastewater is generated per square meter of produced membrane [\u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e48\u003c/span\u003e]. This wastewater holds either 7500 ppm acetone for 100 litres or 500 ppm acetone for 500 litres of wastewater. This paper assumes that 500 litres of water and wastewater are related to the process, with a concentration of 5 ppm acetone per litre of water. Converted to 1 dm\u003csup\u003e2\u003c/sup\u003e, this gives 5 litres of water and wastewater and 2500 mg of acetone emissions. The same amount of acetone is also assumed as input, as this is more than is needed to produce the material itself.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab5\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 5\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eModelling of the phase inversion-based method.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003ematerial\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eD6 (dm\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eD7 (dm\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eWater input (l)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAcetone input (mg)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2500\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2500\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePolymer (kg)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.0003\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.0005\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEnergy (kWh)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.00523\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.00523\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNitrogen (l)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.00000210\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.00000351\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAcetone output (emissions mg)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2500\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2500\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eWastewater output (l)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec20\" class=\"Section4\"\u003e \u003ch2\u003e3.1.2.4 Roll to roll deposition\u003c/h2\u003e \u003cp\u003eRoll-to-roll deposition is a process where materials are transported from one process to another by rolls. Here, only the energy used for the rolls is taken into account. Other assumptions about potential processes would make the process and the output of the LCA calculation too uncertain. To reproduce the energy needed for this process, the energy used from the 'Sheet rolling, aluminium {RER}| processing | Cut-off, U' record is chosen as the density of aluminium is closest to the materials which are in the roll-to-roll process in this paper. This is once again scaled down to an energy use of 0.0000327 kWh/dm\u003csup\u003e2\u003c/sup\u003e.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec21\" class=\"Section3\"\u003e \u003ch2\u003e3.1.3 Environmental impact assessment\u003c/h2\u003e \u003cp\u003eThe results of the EI assessment are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e to Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e. Figure\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e shows the single score environmental impact for all impact categories. Figure\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e shows the same result but highlights the relative contribution of every impact category. Figure\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e shows the single score environmental impact for the different components of the RC materials, and Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e shows the same result, highlighting the relative contribution of the various components.\u003c/p\u003e \u003cp\u003eThe five EI categories with the highest impact, i.e. climate change (CC), acidification (AC), resource use fossils (RUF), resource use minerals and metals (RUMM) and particulate matter (PM), are coloured red. It is clear that CC and RUF are the impact categories with the most significant impact for all materials. Comparing this to Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e and Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e clarifies that this is due to the production processes, specifically the energy use during these processes. More than 75% of the SSEI of materials D1, D2, D3, D8, D9 and D10 is caused by the energy used during the sputtering process. This is because these RC materials have multiple layers of sputtered material, making the sputtering process longer and causing a more significant energy use. This is especially true for materials D2 and D3, with over 20 sputtered layers. The materials only account for less than 10% of the environmental impact of the latter two.\u003c/p\u003e \u003cp\u003eMaterial D4 has only one sputtered layer and still has almost the same impact as D1, with seven sputtered layers. In D4, more silver is used than in the other materials, generating a high environmental impact. This can also be seen in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e, where silver (Ag) is responsible for almost 30% of the EI. The use of silver also generates a high environmental impact for materials D5 and D9.\u003c/p\u003e \u003cp\u003eThe silicon wafer is used for all materials with a sputter deposition and is responsible for a relatively large share of the total SSEI of these materials. Material D5 has a double silicon wafer, which explains the higher SSEI caused by the wafer for this material. Manufacturing a silicon wafer is energy intensive, and this also explains why the ratio of the different environmental impacts is still comparable to the other materials. The spin coating process has almost no contribution to the environmental impact of this material.\u003c/p\u003e \u003cp\u003eOnly for RC materials D6 and D7, the materials are responsible for a more significant share of the impact than the energy use. Here it is clear that the metals, steel and aluminium are responsible for approximately 50% of the SSEI. The additional materials during the phase inversion process also become important. Approximately 10% of the total SSEI is caused by the use of acetone. The energy consumption during the process accounts for 25\u0026ndash;45% of the EI.\u003c/p\u003e \u003cp\u003eLooking at the materials manufactured using a sputtering process, it is clear that material D8 has the lowest EI caused by the materials without considering the impact of the production process. As for the other materials, only the silicon wafer causes a high impact. This is because this material is the only one not using silver in the composition.\u003c/p\u003e \u003cp\u003eWhen comparing the ten materials, it is clear that material D3 has the biggest SSEI due to sputtering, with an environmental impact of 1199.4 \u0026micro;Pt*dm\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e,and materials D6 and D7 have the lowest SSEI due to the absence of this sputtering technique, with an environmental impact of 3.77 and 6.03 \u0026micro;Pt*dm\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e respectively. Also, the materials used for these last two RC materials have a lower EI than those used in the other seven RC materials.\u003c/p\u003e \u003cp\u003eUltimately, when comparing RC materials to a conventional concrete roof tile, it becomes evident that all RC materials, except for D6 and D7, exhibit an environmental impact at least ten times higher. However, it is essential to note that this comparison may not be entirely conclusive, given the uncertainty whether the RC materials will serve as replacements for conventional roof tiles or be added on top of a typical roof structure. Nevertheless, it does provide an initial idea of the environmental implications of these materials in contrast to traditional roofing materials.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e and Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e show the results for climate change. Similar conclusions can be drawn: the energy use during the production processes causes the biggest share of the EI. Only for RC materials D5, D6 and D7, a significant share of the EI is caused by other aspects. For RC material D5, the relative contribution of the silicon wafer increases when only looking at climate change (compared to the SSEI). This can be explained by the high amount of energy needed to produce this layer. The ratio of impact for RC materials D6 and D7 is similar to the total single score, while for the other RC materials, the share of the materials has decreased compared to the SSEI. The results for particulate matter, acidification, resource use fossils and resource use minerals and metals are presented in the additional information: Figures \u003cspan refid=\"MOESM1\" class=\"InternalRef\"\u003eS1\u003c/span\u003e-S8.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec22\" class=\"Section2\"\u003e \u003ch2\u003e3.2 Cooling potential\u003c/h2\u003e \u003cp\u003eThis section presents the simulation results of the cooling potential focusing on the various heat transfer mechanisms influencing cooling power, namely solar, radiative, and convective fluxes. Figure\u0026nbsp;7 illustrates how the intrinsic characteristics of the materials impact the radiative and solar heat fluxes. It is essential to note that radiated heat depends on the emissivity of materials in the infrared wavelength and the surface temperature. Therefore, the lower the temperature is the lower the radiative losses will be. Consequently, the setup in Madrid consistently yields higher radiated values than in Brussels due to its higher surface temperature (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e); RC materials in Madrid are 4.51\u0026deg;C in January and 24,4\u0026deg;C in July compared to the 2.51\u0026deg;C and 17.38\u0026deg;C, respectively, in Brussels. The second aspect of material properties to consider is solar reflectivity, critical for achieving daytime radiative cooling. Materials D6/D7 and D10 exhibit the most favourable behaviour in both locations, achieving cooling energy values of -13.2 and \u0026minus;\u0026thinsp;15.9 kWh\u0026middot;m⁻\u0026sup2; in Brussels and \u0026minus;\u0026thinsp;41.0 and \u0026minus;\u0026thinsp;41.1 kWh\u0026middot;m⁻\u0026sup2; in Madrid during the month of July.\u003c/p\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e8\u003c/span\u003e presents the overall cooling performance of the materials, considering the total energy fluxes, which include solar heat gains, radiative heat losses, and convective heat gains, as discussed previously. Convection significantly influences thermal equilibrium by tending to equalize the surface temperature with the ambient temperature. It has to be noted that all the RC roofs are at sub-ambient temperatures whereas the concrete roof tile has a higher temperature than the ambient. In Brussels, there is a more significant temperature differential between the surface and the ambient air in winter compared to summer; therefore, higher convective heat gains occur in winter.\u003c/p\u003e \u003cp\u003eWhen assessing the global energy balance in Brussels, all materials exhibit positive heat fluxes, meaning they heat up in summer and winter, with higher heat gains in winter due to the influence of convection. During the winter the materials with radiative cooling properties show similar total heat gains as the concrete roof tile (D10 with 21.7 kWh\u0026middot;m⁻\u0026sup2; and D1 with 27.0 kWh\u0026middot;m⁻\u0026sup2;). During the summer, nevertheless, the best-performing RC material consistently demonstrates superior performance (D10 with 2.9 kWh\u0026middot;m⁻\u0026sup2; compared to the worst-performing D1 with 24.3 kWh\u0026middot;m⁻\u0026sup2;).\u003c/p\u003e \u003cp\u003eWhen considering the impact of these materials in Madrid, the best performing materials are able to effectively achieve cooling during summer; moreover, all materials experience heat gains during winter due to the low surface temperature (4.51\u0026deg;C) compared to the ambient temperature (7\u0026deg;C). During the summer, materials D6/7 and D10 exhibit the most significant heat losses, reaching \u0026minus;\u0026thinsp;8.4 kWh\u0026middot;m⁻\u0026sup2; compared to the 15 kWh\u0026middot;m⁻\u0026sup2; of the concrete tile; while during winter, they show heat gains of 7.7 and 6.5 kWh\u0026middot;m⁻\u0026sup2;, respectively. It can be concluded that the RC materials have a similar performance to the performance of the concrete roof tile in winter, especially in Brussels, while we see significant differences during the summer.\u003c/p\u003e \u003cp\u003eTo conclude, in determining the best-performing material, enhanced comfort during winter, reduced overcooling penalty, and greater heat losses during summer should be considered (\u003c/p\u003e \u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab6\" class=\"InternalRef\"\u003e6\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cb\u003eFigure 7.\u003c/b\u003e Monthly accumulated radiated heat and solar gains (kWh\u0026middot;m\u003csup\u003e-2\u003c/sup\u003e) for the roof tile and materials D1 to D10 in Brussels and Madrid for January and July.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab6\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 6\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eAccumulated monthly heat gains (+) or losses (-) of the selected RC materials in Brussels and Madrid: radiated heat losses, solar heat gains, convection heat gains and total value.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"10\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003eRadiant (kWh\u0026middot;m\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e \u003cp\u003eSolar (kWh\u0026middot;m\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c8\" namest=\"c7\"\u003e \u003cp\u003eConvection (kWh\u0026middot;m\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c10\" namest=\"c9\"\u003e \u003cp\u003eTotal (kWh\u0026middot;m\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMaterial\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eJan\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eJul\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eJan\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eJul\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eJan\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003eJul\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c9\"\u003e \u003cp\u003eJan\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c10\"\u003e \u003cp\u003eJul\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"9\" rowspan=\"10\"\u003e \u003cp\u003eBrussels\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTile\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-8,5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-43,9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e15,0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e91,7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e20,9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e-23,2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e27,4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e24,6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eD1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-3.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-8.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e14.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e28.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e18.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e27.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e24.3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eD2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-6.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-17.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e5.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e28.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e18.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e23.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e6.3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eD3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-5.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-15.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e16.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e28.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e18.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e25.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e20.4\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eD4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-6.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-19.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e9.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e28.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e18.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e23.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e8.9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eD5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-5.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-18.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e9.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e28.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e18.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e24.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e9.2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eD6/D7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-6.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-19.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e6.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e28.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e18.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e23.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e5.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eD8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-5.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-16.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e11.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e28.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e18.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e25.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e14.2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eD9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-5.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-14.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e6.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e28.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e18.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e23.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e10.3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eD10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-7.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-18.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e28.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e18.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e21.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e2.9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"9\" rowspan=\"10\"\u003e \u003cp\u003eMadrid\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTile\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-21.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-87.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e37.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e144.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e-32.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e15.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e25.2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eD1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-5.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-22.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e6.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e23.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e17.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e32.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e17.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e33.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eD2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-11.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-45.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e8.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e17.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e32.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e8.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e-4.2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eD3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-9.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-38.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e6.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e26.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e17.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e32.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e14.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e20.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eD4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-12.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-50.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e14.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e17.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e32.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e9.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e-2.7\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eD5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-11.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-49.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e14.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e17.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e32.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e9.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e-2.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eD6/D7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-12.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-50.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e9.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e17.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e32.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e7.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e-8.4\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eD8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-10.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-43.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e18.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e17.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e32.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e11.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e8.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eD9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-9.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-36.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e9.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e17.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e32.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e10.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e5.8\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eD10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-11.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-44.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e3.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e17.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e32.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e6.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e-8.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec23\" class=\"Section2\"\u003e \u003ch2\u003e3.3 Comparative framework\u003c/h2\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e9\u003c/span\u003e and Fig.\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e10\u003c/span\u003e present the environmental impact of the ten RC materials and their cooling performance for the two selected months, January and July, and for the selected cities, Brussels and Madrid. As discussed in the previous section, Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e9\u003c/span\u003e considers radiative heat losses and solar heat gains, while Fig.\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e10\u003c/span\u003e also includes convection. The Pareto front for July is in the upper left corner of the graphs, as the lowest environmental impact and the highest cooling power are in that area. The materials that form the Pareto front are highlighted with a rectangle around their material name. The Pareto front for January is on the bottom left corner, as a low cooling performance is preferred.\u003c/p\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e10\u003c/span\u003e clearly shows that material D6 is the best-performing material considering both the cooling performance and environmental impact, as it is located in the Pareto front both in summer and winter. Material D1 would be a potentially good material only looking into the winter months, but its low cooling performance during summer makes it not preferable. The cooling performance during summer is seen as the most critical parameter to grade RC materials, materials D7, D4 and D5 score well compared to the database. The cooling performance is similar to material D6, only the environmental impact is significantly higher. These results, hence, hold that newly developed RC materials should be benchmarked against these best-performing materials to be competitive with the existing RC materials. The results considering the five selected environmental impact categories (global warming potential, particulate matter, acidifications, resource use fossils and resource use minerals and metals) show that the same materials are located in the pareto front for these impact categories (additional information: Figures S9-S13).\u003c/p\u003e \u003cp\u003eIn addition to assessing cooling power and environmental impact, it is crucial to consider the cost and durability of materials when evaluating their suitability for outdoor applications. The cost of materials, installation, and maintenance can significantly impact the feasibility of a cooling solution. Moreover, materials must withstand prolonged exposure to harsh outdoor conditions, including UV radiation, temperature fluctuations, moisture, and mechanical stress. Durable materials can reduce long-term maintenance and replacement costs, making them more economically and environmentally viable. Therefore, a comprehensive evaluation should balance cooling performance and environmental sustainability with cost-effectiveness and resilience to outdoor exposure, ensuring a holistic approach to outdoor cooling solutions.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"4 Conclusion","content":"\u003cp\u003eThe selection of the existing state-of-the-art RC materials proved that collecting sufficient data to model the materials for environmental impact assessment remains challenging. Numerous data about the materials, production and performances are needed to assess the cradle-to-gate environmental impact and compare the impact related to the performance of the various RC materials being developed. Many assumptions regarding the production processes were needed due to lack of published data. In this paper, data were collected through literature and expert consultation. An uncertainty analysis will be done in a subsequent step of the research based on all the assumptions made to understand better the potential variation in the results obtained due to these uncertainties. Moreover, it is recommended that researchers in the future more transparently report the production processes and that the measurement method and indicators for the performance of RC materials become standardised.\u003c/p\u003e \u003cp\u003eThe single score environmental impact assessment indicated that the production processes, especially the sputtering process, are the biggest contributors to the environmental impact. The sputter process is responsible for more than 75% of the environmental impact for materials D1, D2, D3, D8, D9 and D10. After the impact of the production processes, the usage silver and a silicon wafer also results in a high environmental impact. Changing or choosing a different production technique can significantly lower the EI. The impact for climate change separately showed the same trend as climate change is the impact category with the most significant share of the single score environmental impact, heavily influenced by the energy use throughout the production process. The assessment concluded that two materials, D6 and D7, clearly generate a lower environmental impact, which can be explained by the absence of the sputtering process for these RC materials. Materials D6 and D7 have a single score environmental impact of 3.77 and 6.03 \u0026micro;Pt*dm\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e respectively, while the worst scoring material (D3) caused an impact of 1199.4 \u0026micro;Pt*dm\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eMoreover, when comparatively assessing the environmental impact of RC materials, it is necessary to consider any difference in cooling performance as well. No straightforward comparison of any declared cooling performance of RC materials is currently possible based on existing literature as different methods, indicators and climatic contexts have been used for determining the cooling performance. Consequently, using the reported cooling power or temperature drops to create environmental benchmarks would be misleading. To overcome this, a validated model to calculate the performance of RC materials has been used in this paper. This allows us to present for the first time the cooling performance alongside their environmental impact, offering insight into the most suitable material considering both aspects. The analysis of the ten existing RC materials in winter and summer conditions in Brussels and Madrid indicated that D6 and D10 are the most preferred ones from an environmental and performance perspective. These materials are hence located in the pareto front with a single score environmental impact of 3.77 \u0026micro;Pt*dm\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e and 591.38 \u0026micro;Pt*dm\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e with decreased heat gains in summer of 41 kWh*m\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e and 41.1 kWh*m\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e for materials D6 and D10 respectively.\u003c/p\u003e \u003cp\u003eFinally, in the next step of the research, the sensitivity of the modelling assumptions of the RC materials and the uncertainty of the data will be investigated, as this is a limitation of the current paper. Furthermore, the first mixture(s) of the PMC will be modelled and their environmental impact and performance will be assessed against the RC materials analysed in this paper.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003eAC\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;Acidification\u003c/p\u003e\n\u003cp\u003eAW\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;Atmospheric window\u003c/p\u003e\n\u003cp\u003eCC\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;Climate change\u003c/p\u003e\n\u003cp\u003eEF\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;Ecotoxicity freshwater\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eEI\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;Environmental Impact\u003c/p\u003e\n\u003cp\u003eLCA \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;Life Cycle Assessment\u003c/p\u003e\n\u003cp\u003eMIRACLE\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;Meta concrete with Infrared Radiative Cooling capacity for Large Energy savings\u003c/p\u003e\n\u003cp\u003ePM\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;Particulate matter\u003c/p\u003e\n\u003cp\u003ePMC\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;Photonic meta-concrete\u003c/p\u003e\n\u003cp\u003eRC\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;Radiative Cooling\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eRUF\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;Resource use fossils\u003c/p\u003e\n\u003cp\u003eRUMM\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;Resource use minerals and metals\u003c/p\u003e\n\u003cp\u003eSSEI\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;Single score environmental impact\u003c/p\u003e\n\u003cp\u003eUHI \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;Urban heat island\u0026nbsp;\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and material\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll data generated or analysed during this study are included in this published article and published in the additional file: Figures S1-S13 and Tables S1-S4.10.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing interests\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis project has received funding from the European Union\u0026apos;s Horizon 2020 research and innovation\u003c/p\u003e\n\u003cp\u003eprogramme under grant agreement No 964450\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026apos; contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNA: Conceptualization, methodology environmental impact assessment and comparative framework, formal analysis environmental impact and comparative framework, Writing \u0026ndash; original draft, visualization. LC: \u0026nbsp;methodology cooling potential, formal analysis cooling potential, writing \u0026ndash; original draft cooling potential. KA: Conceptualization, Writing \u0026ndash; Review and Editing, Supervision.\u003c/p\u003e\n\u003cp\u003eAll authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe would like to express my gratitude to Prof. Dr. Irene Taurino (KU Leuven), prof. Dr. Alicia Torres (Public University of Navarre)\u0026nbsp;and researchers from the Leuven NanoCentre for their invaluable assistance and expert guidance in modeling the thin film deposition techniques used in this research. \u0026nbsp;\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eUnited nations. 68% of the world population projected to live in urban areas by 2050, says UN, \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.un.org/development/desa/en/news/population/2018-revision-of-world-urbanization-prospects.html\u003c/span\u003e\u003cspan address=\"https://www.un.org/development/desa/en/news/population/2018-revision-of-world-urbanization-prospects.html\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. Accessed 3 March 2023.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eElliot T, Bab\u0026iacute; Almenar J, Rugani B (2020) Modelling the relationships between urban land cover change and local climate regulation to estimate urban heat island effect. Urban For Urban Green 50:126650. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.ufug.2020.126650\u003c/span\u003e\u003cspan address=\"10.1016/j.ufug.2020.126650\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMohajerani A, Bakaric J, Jeffrey-Bailey T (2017) The urban heat island effect, its causes, and mitigation, with reference to the thermal properties of asphalt concrete. J Environ Manage 197:522\u0026ndash;538. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.jenvman.2017.03.095\u003c/span\u003e\u003cspan address=\"10.1016/j.jenvman.2017.03.095\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDelmastro C, Martinez-Gordon R (2023) Tracking Space Cooling. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.iea.org/energy-system/buildings/space-cooling#tracking\u003c/span\u003e\u003cspan address=\"https://www.iea.org/energy-system/buildings/space-cooling#tracking\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLiu J, Zhou Z, Zhang J, et al (2019) Advances and challenges in commercializing radiative cooling. Materials Today Physics 11:100161. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.mtphys.2019.100161\u003c/span\u003e\u003cspan address=\"10.1016/j.mtphys.2019.100161\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSantamouris M, Papadopoulos A M, Paolini R et al (2021). Cool roofs cost benefit analysis. Research Plan and Progress Report. School of Built ENVIRONMENT, UNSW Sydney, Australia.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGivoni B (1976) Man, climate and architecture. applied science publishers 572\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNahar NM, Sharma P, Purohit MM (2003) Performance of different passive techniques for cooling of buildings in arid regions. Build Environ 38:109\u0026ndash;116. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/S0360-1323(02)00029-X\u003c/span\u003e\u003cspan address=\"10.1016/S0360-1323(02)00029-X\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHanif M, Mahlia TMI, Zare A, et al (2014) Potential energy savings by radiative cooling system for a building in tropical climate. Renewable and Sustainable Energy Reviews 32:642\u0026ndash;650. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.rser.2014.01.053\u003c/span\u003e\u003cspan address=\"10.1016/j.rser.2014.01.053\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eEicker U, Dalibard A (2011) Photovoltaic-thermal collectors for night radiative cooling of buildings. Solar Energy 85:1322\u0026ndash;1335. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.solener.2011.03.015\u003c/span\u003e\u003cspan address=\"10.1016/j.solener.2011.03.015\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRaman AP, Anoma MA, Zhu L, et al (2014) Passive radiative cooling below ambient air temperature under direct sunlight. Nature 515:540\u0026ndash;544. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1038/nature13883\u003c/span\u003e\u003cspan address=\"10.1038/nature13883\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhai Y, Ma Y, David SN, et al (2017) Scalable-manufactured randomized glass-polymer hybrid metamaterial for daytime radiative cooling. Science (1979) 355:1062\u0026ndash;1066. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1126/science.aai7899\u003c/span\u003e\u003cspan address=\"10.1126/science.aai7899\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLim XZ (2020) The super-cool materials that send heat to space. Nature 577:18\u0026ndash;20. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1038/d41586-019-03911-8\u003c/span\u003e\u003cspan address=\"10.1038/d41586-019-03911-8\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCarlosena L, Ruiz-Pardo \u0026Aacute;, Feng J, et al (2020) On the energy potential of daytime radiative cooling for urban heat island mitigation. Solar Energy 208:430\u0026ndash;444. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.solener.2020.08.015\u003c/span\u003e\u003cspan address=\"10.1016/j.solener.2020.08.015\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAdams N, Allacker K (2022) Development of a Radiative Cooling Material Database to Benchmark the Environmental Impact of a newly Developed Photonic Meta-Concrete. In: SETAC Europe annual meeting 2022. p 12\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMerlo A, L\u0026eacute;onard G (2021) Magnetron sputtering vs. Electrodeposition for hard chrome coatings: A comparison of environmental and economic performances. Materials 14:. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.3390/ma14143823\u003c/span\u003e\u003cspan address=\"10.3390/ma14143823\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTyona MD (2013) A theoritical study on spin coating technique. Advances in materials Research 2:195\u0026ndash;208. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.12989/amr.2013.2.4.195\u003c/span\u003e\u003cspan address=\"10.12989/amr.2013.2.4.195\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYadav P, Ismail N, Essalhi M, et al (2021) Assessment of the environmental impact of polymeric membrane production. J Memb Sci 622:118987. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.memsci.2020.118987\u003c/span\u003e\u003cspan address=\"10.1016/j.memsci.2020.118987\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCresko J, Shenoy D, Liddell H P H, et al (2015) Quadrennial Technology. Innovating clean energy Technologies in advanced manufacturing.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMakhlouf S (2021) Life Cycle Assessment (LCA) analysis for flexible thin-film solar cells at HyEt Solar. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttp://resolver.tudelft.nl/uuid:738d603b-4aba-4c1a-8c\u003c/span\u003e\u003cspan address=\"http://resolver.tudelft.nl/uuid:738d603b-4aba-4c1a-8c\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e82-2b4a08c09670.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSala S, Cerutti A K, Pant R, (2018). Development of a weighting approach for the Environmental Footprint. Publications Office of the European Union: Luxembourg.\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.2760/446145\u003c/span\u003e\u003cspan address=\"10.2760/446145\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCarlosena L, Ruiz-Pardo \u0026Aacute;, Rodr\u0026iacute;guez-Jara E\u0026Aacute;, Santamouris M (2023) Worldwide potential of emissive materials based radiative cooling technologies to mitigate urban overheating. Build Environ 243:. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.buildenv.2023.110694\u003c/span\u003e\u003cspan address=\"10.1016/j.buildenv.2023.110694\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMeteonorm 7. Http://Meteonorm.Ch. Accessed 1 August 2023.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMandal J, Fu Y, Overvig AC, et al (2018) Hierarchically porous polymer coatings for highly efficient passive daytime radiative cooling. Science (1979) 362:315\u0026ndash;319. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1126/science.aat9513\u003c/span\u003e\u003cspan address=\"10.1126/science.aat9513\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKecebas MA, Menguc MP, Kosar A, Sendur K (2017) Passive radiative cooling design with broadband optical thin-film filters. J Quant Spectrosc Radiat Transf 198:1339\u0026ndash;1351. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.jqsrt.2017.03.046\u003c/span\u003e\u003cspan address=\"10.1016/j.jqsrt.2017.03.046\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRephaeli E, Raman A, Fan S (2013) Ultrabroadband photonic structures to achieve high-performance daytime radiative cooling. Nano Lett 13:1457\u0026ndash;1461. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1021/nl4004283\u003c/span\u003e\u003cspan address=\"10.1021/nl4004283\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhai Y, Ma Y, David SN, et al (2017) Scalable-manufactured randomized glass-polymer hybrid metamaterial for daytime radiative cooling. Science (1979) 355:1062\u0026ndash;1066. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1126/science.aai7899\u003c/span\u003e\u003cspan address=\"10.1126/science.aai7899\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKou J long, Jurado Z, Chen Z, et al (2017) Daytime Radiative Cooling Using Near-Black Infrared Emitters. ACS Photonics 4:626\u0026ndash;630. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1021/acsphotonics.6b00991\u003c/span\u003e\u003cspan address=\"10.1021/acsphotonics.6b00991\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eOsuna Ruiz D, Lezaun C, Torres-Garc\u0026iacute;a AE, Beruete M (2023) Metal-free design of a multilayered metamaterial with chirped Bragg grating for enhanced radiative cooling. Opt Express 31:22698. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1364/oe.492404\u003c/span\u003e\u003cspan address=\"10.1364/oe.492404\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKecebas MA, Menguc MP, Kosar A, Sendur K (2020) Spectrally selective filter design for passive radiative cooling. Journal of the Optical Society of America B 37:1173. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1364/josab.384181\u003c/span\u003e\u003cspan address=\"10.1364/josab.384181\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMattox M, D (2010) Handbook of Physical Vapor Deposition (PVD) Processing, Second. William Andrew Publishing\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eEPFL. Pfeiffer SPIDER 600, \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.epfl.ch/research/facilities/cmi/equipment/thin-films/pfeiffer-spider-600/;\u003c/span\u003e\u003cspan address=\"https://www.epfl.ch/research/facilities/cmi/equipment/thin-films/pfeiffer-spider-600/;\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. Accessed 7 October 2022.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFiameni S, Battiston S, Castellani V, et al (2021) Implementing sustainability in laboratory activities: A case study on aluminum titanium nitride based thin film magnetron sputtering deposition onto commercial laminated steel. J Clean Prod 285:124869. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.jclepro.2020.124869\u003c/span\u003e\u003cspan address=\"10.1016/j.jclepro.2020.124869\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMerlo A, L\u0026eacute;onard G (2022). Use of Environmental Assessment and Techno Economic Analysis (TEA) to Evaluate the Impact and Feasibility of Coatings for Manufacturing Processes. Computer Aided Chemical Engineering 49:2071\u0026ndash;2076.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eClassen M, Althaus H-J, Blaser S, et al (2009) Life Cycle Inventories of Metals. Final report ecoinvent data v21 No 10 1\u0026ndash;926.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMerlo A, L\u0026eacute;onard G (2021) Magnetron sputtering vs. Electrodeposition for hard chrome coatings: A comparison of environmental and economic performances. Materials 14:. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.3390/ma14143823\u003c/span\u003e\u003cspan address=\"10.3390/ma14143823\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eO\u0026rsquo;Hanlon JF (2003) A User\u0026rsquo;s Guide to Vacuum Technology. Wiley. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1002/0471467162\u003c/span\u003e\u003cspan address=\"10.1002/0471467162\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMaterials Research Facilities Network. ATC-2000F AJA SPUTTERING SYSTEM, \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.mrfn.org/instruments/nanomaterials-thin-films/atc-2000f-aja-sputtering-system\u003c/span\u003e\u003cspan address=\"https://www.mrfn.org/instruments/nanomaterials-thin-films/atc-2000f-aja-sputtering-system\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. Accessed 7 October 2022.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eToronto Nanofabrication Centre Quotation. Sputter deposition recipes. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://tnfc.utoronto.ca/tnfc/user-access/user-recipes/sputter-depositon-recipes/;\u003c/span\u003e\u003cspan address=\"https://tnfc.utoronto.ca/tnfc/user-access/user-recipes/sputter-depositon-recipes/;\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. Accessed 7 October 2022.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eExplorer 14 recipes. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.seas.upenn.edu/~nanosop/Explorer14_Recipes.htm\u003c/span\u003e\u003cspan address=\"https://www.seas.upenn.edu/~nanosop/Explorer14_Recipes.htm\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e; 2021. Accessed 7 October 2022.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWang Z, Wallra A, Poto\u0026pound;nik A, et al (2015) Development of Sputtering Process for High Quality Nb Thin Film Project supervisor: Phelma tutor\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKaplan K, Kim K, Winterkorn M, et al (2016) Optimizing the Electrical Stability of Platinum Films Deposited in Lesker-Sputter\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGong J, Darling SB, You F (2015) Perovskite photovoltaics: Life-cycle assessment of energy and environmental impacts. Energy Environ Sci 8:1953\u0026ndash;1968. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1039/c5ee00615e\u003c/span\u003e\u003cspan address=\"10.1039/c5ee00615e\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCelik I, Song Z, Cimaroli AJ, et al (2016) Life Cycle Assessment (LCA) of perovskite PV cells projected from lab to fab. Solar Energy Materials and Solar Cells 156:157\u0026ndash;169. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.solmat.2016.04.037\u003c/span\u003e\u003cspan address=\"10.1016/j.solmat.2016.04.037\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eEspinosa N, Serrano-Luj\u0026aacute;n L, Urbina A, Krebs FC (2015) Solution and vapour deposited lead perovskite solar cells: Ecotoxicity from a life cycle assessment perspective. Solar Energy Materials and Solar Cells 137:303\u0026ndash;310. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.solmat.2015.02.013\u003c/span\u003e\u003cspan address=\"10.1016/j.solmat.2015.02.013\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGarc\u0026iacute;a-Valverde R, Cherni JA, Urbina A (2010) Life cycle analysis of organic photovoltaic technologies. Progress in Photovoltaics: Research and Applications 18:535\u0026ndash;558. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1002/pip.967\u003c/span\u003e\u003cspan address=\"10.1002/pip.967\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePr\u0026eacute;z\u0026eacute;lus F, Tiruta-Barna L, Guigui C, Remigy JC (2021) A generic process modelling \u0026ndash; LCA approach for UF membrane fabrication: Application to cellulose acetate membranes. J Memb Sci 618:. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.memsci.2020.118594\u003c/span\u003e\u003cspan address=\"10.1016/j.memsci.2020.118594\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRazali M, Kim JF, Attfield M, et al (2015) Sustainable wastewater treatment and recycling in membrane manufacturing. Green Chemistry 17:5196\u0026ndash;5205. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1039/c5gc01937k\u003c/span\u003e\u003cspan address=\"10.1039/c5gc01937k\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"environmental-sciences-europe","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"eseu","sideBox":"Learn more about [Environmental Sciences Europe](http://enveurope.springeropen.com)","snPcode":"12302","submissionUrl":"https://submission.nature.com/new-submission/12302/3","title":"Environmental Sciences Europe","twitterHandle":"@SpringerOpen","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"LCA, thin film deposition techniques, sputter deposition, cooling potential","lastPublishedDoi":"10.21203/rs.3.rs-4580586/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4580586/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eBackground\u003c/p\u003e\n\u003cp\u003eBy the end of 2050, it is expected that 68% of the population will live in urban areas. A higher density of people living in cities generates an increased urban heat island. Radiative cooling (RC) materials are proposed as a key strategy to mitigate global warming and urban heating. The Horizon 2020 project MIRACLE aims at developing a new RC material based on conventional concrete.\u003c/p\u003e\n\u003cp\u003eThis paper presents a framework developed for comparing both the cradle-to-gate environmental impact and cooling potential of the newly developed photonic meta-concrete (or any other new RC material) with existing RC materials. The framework is applied to various RC materials using the generic Ecoinvent v3.6 database. The impact assessment method is in line with the Belgian life cycle assessment method for buildings and covers the 15 environmental impact categories of the EN15804:A2. The cooling performance is assessed by implementing the material spectral emissivity into a thermal model for Brussels and Madrid.\u003c/p\u003e\n\u003cp\u003eResults\u003c/p\u003e\n\u003cp\u003eCollecting sufficient data to model the state-of-the-art RC materials is challenging, requiring numerous data points on materials, production, and performance, leading to many assumptions due to a lack of data. The study showed that the sputtering process contributes over 75% to the environmental impact of several materials, while materials which do not use this process, have significantly lower impacts. The assessment of the cooling potential showed that convection heat gains make it difficult to create an all-year round cooling material. The comparison with a conventional building material, a concrete roof tile, hence shows great potential for these RC materials as heating gains during summer are significantly reduced. Analysing cooling performance alongside environmental impact, the study identified two RC materials as the most preferred in both Brussels and Madrid, considering their lower environmental impact and superior performance.\u003c/p\u003e\n\u003cp\u003eConclusions\u003c/p\u003e\n\u003cp\u003eA standardised way to asses and benchmark RC materials based on their cradle-to-gate environmental impact and cooling performance was lacking. For the first time, a comparison for RC materials considering these characteristics is presented. This comparison identified the most competitive RC materials, which will serve as benchmarks for the newly developed photonic meta-concrete.\u003c/p\u003e","manuscriptTitle":"Evaluating the cradle-to-gate Environmental Impact and cooling performance of Advanced Daytime Radiative Cooling Materials to Establish a Comparative Framework for a Novel Photonic Meta-Concrete","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-07-12 20:10:04","doi":"10.21203/rs.3.rs-4580586/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2024-08-10T12:49:43+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-08-09T02:56:41+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-08-05T00:04:58+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-07-23T02:15:48+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"304584526195246677528120222055361805326","date":"2024-07-14T23:43:57+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"207776817261414119840893985359569990031","date":"2024-07-09T10:07:27+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"288574757178714880015257960607257769658","date":"2024-07-08T12:56:54+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"221281320876408077228158651482983798506","date":"2024-07-08T10:23:09+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2024-07-02T07:33:05+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-06-18T11:27:24+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2024-06-18T11:24:40+00:00","index":"","fulltext":""},{"type":"submitted","content":"Environmental Sciences Europe","date":"2024-06-14T08:22:03+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"environmental-sciences-europe","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"eseu","sideBox":"Learn more about [Environmental Sciences Europe](http://enveurope.springeropen.com)","snPcode":"12302","submissionUrl":"https://submission.nature.com/new-submission/12302/3","title":"Environmental Sciences Europe","twitterHandle":"@SpringerOpen","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"793a6846-ec85-48b6-a720-732840727d2e","owner":[],"postedDate":"July 12th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2024-10-14T15:59:58+00:00","versionOfRecord":{"articleIdentity":"rs-4580586","link":"https://doi.org/10.1186/s12302-024-01005-5","journal":{"identity":"environmental-sciences-europe","isVorOnly":false,"title":"Environmental Sciences Europe"},"publishedOn":"2024-10-08 15:57:11","publishedOnDateReadable":"October 8th, 2024"},"versionCreatedAt":"2024-07-12 20:10:04","video":"","vorDoi":"10.1186/s12302-024-01005-5","vorDoiUrl":"https://doi.org/10.1186/s12302-024-01005-5","workflowStages":[]},"version":"v1","identity":"rs-4580586","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4580586","identity":"rs-4580586","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}