Heat Transfer Studies on Sodium based PCM Infused Mattress

Heat Transfer Studies on Sodium based PCM Infused Mattress | Authorea try { document.documentElement.classList.add('js'); } catch (e) { } var _gaq = _gaq || []; _gaq.push(['_setAccount', 'G-8VDV14Y67G']); _gaq.push(['_trackPageview']); (function() { var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s); })(); Skip to main content Preprints Collections Wiley Open Research IET Open Research Ecological Society of Japan All Collections About About Authorea FAQs Contact Us Quick Search anywhere Search for preprint articles, keywords, etc. Search Search ADVANCED SEARCH SCROLL Heat Transfer This is a preprint and has not been peer reviewed. Data may be preliminary. 29 July 2025 V1 Latest version Share on Heat Transfer Studies on Sodium based PCM Infused Mattress Authors : M. Raja , SSivalakshmi , TBalusamy , MSudharshan , TGopalakrishnan , and Deepa Simon [email protected] Authors Info & Affiliations https://doi.org/10.22541/au.175377128.84686509/v1 370 views 269 downloads Contents Abstract Information & Authors Metrics & Citations View Options References Figures Tables Media Share Abstract Temperature is a crucial factor influencing the quality of sleep, as it directly affects thermal comfort during sleep. The present work reports the investigation of the thermal performance of high-density (HDF) and low-density (LDF) polyurethane foam mattresses impregnated with sodium-based Phase Change Materials (PCMs) and their efficacy in temperature buffering features. A controlled laboratory study comparing exposure to these mattresses was conducted by installing mattresses in an insulated wooden box and simulating body heat with incandescent light bulbs. Ten different mattress designs were tested, including variations such as the addition of PCM and perforations for maximum heat dissipation. A multichannel record system and a hygrometer were employed to constantly monitor the temperature and relative humidity, respectively. The results were both statistically significant and reliable, as confirmed by error and ANOVA tests (P < 0.0001). Among all the samples, it was found that PCM1/LDF possessed the most efficient thermal regulation capacity at a temperature difference of 6.98 °C, which is most suitable for improving sleep comfort. These results provide a way to enhance user thermal comfort by providing informative data for better mattress design. M.Raja 1* , S.Sivalakshmi 1 , T.Balusamy 1 , M.Sudharshan 1 , T.Gopalakrishnan 2 Deepa Simon 3 * 1 Department of Mechanical Engineering, Government College of Engineering Salem, Tamil Nadu, India - 636011. 2 Department of Mechanical Engineering, Vels Institute of Science Technology and Advanced Studies (VISTAS), Chennai, Tamil Nadu, India – 600117. 3 Department of Manufacturing, Saveetha School of Engineering, SIMATS, Saveetha University, Chennai, Tamil Nadu 600077, India. * Corresponding Authors: [email protected] (M. Raja), [email protected] (S.Deepa) Abstract Temperature is a crucial factor influencing the quality of sleep, as it directly affects thermal comfort during sleep. The present work reports the investigation of the thermal performance of high-density (HDF) and low-density (LDF) polyurethane foam mattresses impregnated with sodium-based Phase Change Materials (PCMs) and their efficacy in temperature buffering features. A controlled laboratory study comparing exposure to these mattresses was conducted by installing mattresses in an insulated wooden box and simulating body heat with incandescent light bulbs. Ten different mattress designs were tested, including variations such as the addition of PCM and perforations for maximum heat dissipation. A multichannel record system and a hygrometer were employed to constantly monitor the temperature and relative humidity, respectively. The results were both statistically significant and reliable, as confirmed by error and ANOVA tests (P < 0.0001). Among all the samples, it was found that PCM1/LDF possessed the most efficient thermal regulation capacity at a temperature difference of 6.98 °C, which is most suitable for improving sleep comfort. These results provide a way to enhance user thermal comfort by providing informative data for better mattress design. Keywords: Phase Change Materials, Polyurethane foam Mattresses, Human thermal comfort. Abbreviations PCM Phase Change Material PCM1 Disodium Phosphate Dodecahydrate PCM2 Sodium Thiosulphate Pentahydrate HDF High-Density Foam LDF Low-Density Foam ∆T Temperature Difference Introduction An essential biological process, sleep is crucial for maintaining optimal physical, mental, and emotional health [1]. Thermal comfort is one of the major contributors influencing the quality of sleep, among several others. The thermal conditions of sleep highly influence sleep latency, sleep stages and sleep patterns in general . Discrepancies may lead to discomfort, sleep disturbance, and impaired sleep efficiency, whereas an optimal temperature fosters unperturbed, stabilized sleep [2]. Hence, it is necessary to study the promotion of thermal comfort during sleep, which in turn involve s mechanisms that improve general health through enhanced sleep quality. The temperature in the room, the bedding you use, and, most importantly, your mattress all contribute to thermal comfort as you sleep. The mattress, being the primary interaction surface between the sleeper and his/her sleep environment, is critical for thermal control and heat regulation. To address these issues, advanced materials, such as phase change materials (PCMs), have been investigated for use in mattresses to enhance thermal performance , and PCMs are one of the most promising approaches [3]. PCMs are substances that absorb, store, and release a substantial amount of latent heat as they change phase, mainly between the solid and liquid phases. By capturing additional body heat as the person becomes warm and returning any stored heat as the sleeper cools, they find this aspect of PCMs serves to buffer temperature changes and create a more comfortable, steady microclimate. Nowadays, the application of PCMs (as a new technology) in mattresses and sleep products has become interesting for various industries, particularly the bedding industry. Research has suggested that the materials , ls used in mattresses and textiles are effective in improving comfort and thermal control [4, 5]. Most mattress users are 20–30-year-old women with an income of less than $100,000. Our health and our quality of life are paramount. For the most part, consumers opt for environmentally safe and recyclable materials [6]. For instance, the mechanical performance and thermal insulating properties of polyurethane foam mattresses could be improved by PCMs introduction. This cost-effective temperature regulation system improves the sleeping comfort of low-density foam [7, 8]. However, PU foams themselves are surrounded by a highly flammable natural foam material; therefore, studies on making the chemical composition of the foam suitable for thermal stability and fire resistance, which are the standards for the safety of use, for use in the field of mattresses, automobile interior materials, and insulation are needed [9,10]. Perforated (Hole) foam structures have been demonstrated to improve heat dissipation, leading to better thermal control as well [11, 12]. This suggests that the addition of PCM to the mattress structure may enhance sleep quality. Apart from material, choosing mattresses that strike a comfortable and supportive balance is important. Mattresses need to be able to accommodate various sleeping positions and ensure ideal spinal alignment. Research on comfort and support properties has demonstrated that the physical and ergonomic compatibility of the mattress layers has a strong influence on the sensation a user experiences when using a mattress [13]. The quality of sleep may differ for users with various profiles because people with different thermal needs exhibit different reactions to skin temperature, bed microclimatic conditions, and insulation thickness, as shown in thermal preference studies [14]. Recent systematic reviews of body cooling interventions have reported that bedding that cools can decrease core body temperature in the short term, with potential implications for sleep parameters, such as sleep onset latency or total sleep time [15]. Moreover, access to or combination with the use of integrated systems (i.e., thermoregulation mats, underfloor Heating/cooling) maximises sleep quality, as skin and surface temperatures are optimised unless overheating (potentially hazardous increases in core body temperature) is avoided [16]. A personalised thermal conditioning system featuring personalised radiant heating and cooling also enhances thermal comfort. Depending on occupant behaviour, they allow for localizedlocalizedanagement, enabling customizedcustomizedfurniture to be realizedrealizedCooling textiles have also undergone advancements to enhance moisture adsorption, breathability, and intelligent temperature control, paving the way for new possibilities in bedding utilization notably, parallel progress in precision cooling for animals (e.g., spray and air-forced systems) also highlights the significance of in-the-moment thermal control guided by biometric data. This direction can be translated for human sleep product development [19]. Despite the sophistication of these materials, a majority of the studies conducted with PCMs relate to expensive paraffin-based EMs, which triggers economic concerns since many retailers now concentrate on the price when purchasing a mattress. To fill this gap, this research suggests the application of selective salt hydrate phase change materials (PCMs) as an economically viable alternative, incorporated into high-density foam (HDF) and low-density foam (LDF) mattresses. Additionally, perforations are incorporated into the foam structure to facilitate natural ventilation and heat dissipation, maintaining mechanical integrity and thereby further enhancing total thermal comfort. Realistic thermal management examples are found in the literature on temperature control research for incubator systems with incandescent lamps. These findings demonstrate how three bulbs in a series can effectively achieve the desired temperatures under ON-OFF control. This approach applies to evaluating temperature regulation in bedding systems, as it could be a reliable substitute for simulating human body heat [20, 21]. The objective of this work is to comprehensively investigate the thermal behaviours of perforated and non-perforated mattresses made of polyurethane foam with PCM inclusion and varying densities. To achieve an accurate thermal performance, a laboratory is designed to simulate the warmth of the human body. The findings are expected to aid in the development of optimal mattresses for thermal comfort performance, informed by empirical data. In short, thermal comfort is a crucial factor in the quality of sleep, and the mattress serves as a means of controlling the thermal environment that the sleeper experiences. One method to enhance temperature regulation is to incorporate low-cost sodium-based phase change materials (PCMs) into polyurethane foam mattresses. The purpose of this work is to provide a comprehensive evaluation of the strategies, aiming to gain a deeper insight into their influence on mattress thermal performance and thus propose guidance for designing sleep systems with optimal thermal comfort. Materials and experimental methodology not-yet-known not-yet-known not-yet-known unknown 2.1 Foam materials and mechanical behaviour PU foam contributes to fire safety by reducing heat release, smoke toxicity, and emissions during burning, especially when combined with fire-retardant textiles. It is a suitable candidate as a material that provides both fire resistance and thermal insulation properties due to its delamination, prevention of flashover, and flame spread retardation [22]. Since polyurethane foam exhibits excellent cushioning performance and durability and can also be modified to enhance heat regulation, it was selected for this study. Two types of foam, High-Density Foam (HDF) (32 kg/m³) and Low-Density Foam (LDF) (18 kg/m³), were used for this study. Both types were investigated with the addition of Phase Change Materials (PCMs) to enhance temperature control. As shown in the figures below, a clear difference in porosity exists between these foams, with the low-density foam exhibiting higher porosity and the high-density foam showing lower porosity. The microstructure of high-density foam is shown in Figure 1, highlighting the compact cell arrangement that provides firmer support and reduced air permeability. The low-density foam’s structure is seen in Figure 2, where its more porous and open design improves softness and airflow. Fig 1. Microstructure of HDF Fig 2 . Microstructure of LDF 2.2 PCMs Selection and Characterization Change materials are Substances that absorb and release thermal energy during phase transitions—usually between solid and liquid states. They are perfect for thermal management applications, such as mattresses, because they assist in controlling temperature by holding excess heat and releasing it when the ambient temperature is lower than the PCM temperature. The 80-gram PCM packets were placed on top of each layer of foam within the testing chamber after being sealed in water-proofed aluminium pouches. To ensure precision, the PCM’s weight was measured carefully using a digital weighing scale, as illustrated in Fig. 3. Due to their excellent thermal properties, which can provide high heat absorption and release, sodium phosphate dodecahydrate (PCM1) and sodium thiosulfate pentahydrate (PCM2) were selected. Due to its high latent heat capacity and stable phase change properties, PCM1 is an effective material for long-term thermal control. Deferred heat collection and dissipation, as a result of more retention of heat by PCM2, enhances the temperature profile. Table 1 presents the thermophysical properties of PCM1, including its melting point, latent heat, and thermal conductivity, which can be utilised to regulate the temperature efficiently. The phase transition properties and heat storage of PCM, which are important for improving sleep comfort, are shown in Table 2. Tables with the properties of the two PCMs are given below, Table 1 Thermophysical properties of Sodium-based PCMs Chemical Formula Na₂HPO₄·12H₂O Na₂S₂O₃·5H₂O Molecular Weight 380.12 g/mol 248.18 g/mol Density 1.25–1.35 g/cm³ 1.67 g/cm³ Phase Change Temp 33–35°C 42–48°C Latent Heat 280 kJ/kg 210 kJ/kg Specific Heat 1.5–2.5 J/g·K 1.2–2.0 J/g·K Thermal Conductivity 0.5 W/m·K 0.54 W/m·K Solubility Soluble in water Highly soluble Appearance White crystalline solid White crystalline solid 3. Experimental design and thermal testing methodology 3.1 Construction of the testing chamber The Environmental Testing Setup was constructed using timber, forming a four-sided enclosure with dimensions of 120 cm × 120 cm × 17.25 cm (width × length × height). The setup features a manually operable upper section, allowing convenient access for adjustments. To enhance thermal performance, insulation was applied on all sides to minimize and maintain stable internal conditions throughout the experiment. The setup was designed to replicate real-world mattress structures, incorporating two types of polyurethane foam—high-density foam (32 kg/m³) and low-density foam (18 kg/m³)—with and without Phase Change Materials (PCMs) for comparative analysis. Sodium Phosphate Dodecahydrate (PCM1) and Sodium Thiosulfate Pentahydrate (PCM2) were selected for their effective latent heat storage properties, which contribute to thermal regulation. To integrate PCMs into the system, eighty-gram aluminium pouches were placed above the top and middle foam layers within the setup. The mass of each PCM packet was precisely measured using a digital weighing scale (Fig. 8) to ensure accuracy. Uniform thermal distribution and optimal interaction between the foam and PCMs were achieved through the layered arrangement. To improve heat transfer efficiency and increase the contact area between PCMs and their neighbouring material, holes with a diameter of 20 mm were punched on the foam layers. Fig. 12 is a schematic side view of a cross-sectional foam structure containing holes. 3.2 System for measuring temperature and logging data T-type thermocouples were employed in the present study due to their reliability, wide measurement range, and ease of integration. Thermocouples were implanted in a polyurethane foam mattress to measure the thermal gradients established during the experiment. All mattress configurations contained 12 T-type thermocouples (TT-T-20G-72M-M connectors) strategically placed at the ambient, top, middle, and bottom layers to sense real-time temperature trends. These thermocouples are rated to measure temperatures from -200°C to 350°C (-328°F to 662°F) with a sensitivity of ±0.5%, which is very good for determining thermal performance. Calibration of the Thermocouples: Prior to use, the thermocouples were calibrated using 0°C (ice bath) and 100°C (boiling water) as a two-point calibration procedure to ensure accurate temperature readings were being obtained. All deviations were adjusted prior to experiments. The thermocouples were connected to a multichannel data acquisition (DAQ) system to enable continuous temperature measurement and logging. The DAQ system was manually set to acquire ten values of temperature in the mattress, both with and without PCMs incorporated. 3.3 Heater Design and Specification The experimental configuration was adapted to incorporate an original heating installation designed to simulate the metabolic heat release of the human body while sleeping. Research has shown that at rest, the human body dissipates approximately 100 W of heat [23]. Temperature control experiments in incubator systems with incandescent light bulbs, as reported in the literature, provide valuable information on realistic thermal regulation. Based on these findings, these findings, a three-lamp cluster with ON-OFF control provides the required temperatures and maintains them. In evaluating the thermal comfort of bedding systems, this approach can be a reliable alternative to simulating human body temperature [20, 21]. The heater was used to simulate this environment , utilising 40W incandescent bulbs (117W with 98% heat efficiency, representing the heat generated by a human body). To ensure consistent heating over the mattress surface, the bulbs were evenly distributed and spaced across the top layer of the testing room. The use of both AC and DC as source operating voltages for the heater provided flexibility in experimentation. The schematic and pictorial views of the heater are depicted in Fig. 4 and Fig. 5, respectively. Fig 3. Schematic illustration of experiment configuration Fig 4. Configured view for heater arrangement with bulbs It was connected to a National Instruments (NI) DAQ card, consisting of 10 input channels, which made the measurement of temperature data more accurate. Numerous modular parts were integrated into the NI DAQ chassis, ensuring a seamless exchange of information and effective power distribution among system components. To acquire data continuously, the backplane was designed to be installed in the chassis for hot-swappable module replacement, thereby avoiding system downtime. Temperature measurement data from the thermocouples were continuously monitored and recorded in real-time via dedicated data acquisition software, controlled by a computer. This arrangement enabled the accurate measurement of the temperature gradient between the multiple layers of foam, ensuring the accuracy of thermal performance evaluation. The DAQ system setup is illustrated in Figure 6, and the PC interface for data logging and processing is displayed in Figure 7. Taken together, these images provide a good visual representation of system integration, which is the seamless interaction between the computer and the DAQ system for dynamic data acquisition and processing. Fig 5. NI DAQ system for thermal data collection not-yet-known not-yet-known not-yet-known unknown Fig 6. Embedded T-type thermocouples in foam layers Fig 7. Thermocouple wiring connections Fig 8. Encapsulated PCM pouches (80g each) Fig 9. Perforated foam structure for enhanced airflow Fig 10. Complete experimental setup for mattress thermal testing 3.2 Testing Protocol and data collection strategy The experiment was conducted in multiple phases to assess thermal performance under controlled conditions. The Environmental Testing Setup was first allowed to reach thermal equilibrium for 30 minutes before recording temperature data. The procedure involved the following steps: 1. Baseline Measurement (Without PCMs): 2. The temperatures of high-density and low-density foam were recorded without phase change materials (PCMs). 3. Readings were taken continuously to establish the baseline thermal response of the foam layers. 4. PCM-Integrated Measurement: 5. PCM1 (Sodium Phosphate Dodecahydrate) and PCM2 (Sodium Thiosulphate Pentahydrate) were placed above the top and middle foam layers for evaluation. 6. The heater was turned on to gradually raise the setup temperature. 7. The DAQ system was used to record temperature fluctuations continuously. 8. Data Collection and Analysis: 9. Thermocouples took temperature readings at the top (T3), middle (T2), and bottom (T1) layers of the foam. 10. Layer-wise temperature calculations were performed using the equations: Temperature at the bottom layer (T1) = (A1 + A2 + A3) / 3Temperature at the middle layer (T2) = (B1 + B2 + B3) / 3Temperature at the top layer (T3) = (C1 + C2 + C3) / 3Where: • A1, A2, A3 – Thermocouple readings at the bottom layer • B1, B2, B3 – Thermocouple readings at the middle layer • C1, C2, C3 – Thermocouple readings at the top layer 1. Graphical Representation: 2. The recorded data were tabulated in Excel sheets, and graphs were plotted with: 3. Time (minutes) on the x-axis 4. Temperature (°C) on the y-axis 5. The plotted data visually demonstrated temperature regulation trends in foam with and without PCM. 4. Results and analysis Experimental tests utilized phase change materials (PCMs) and structural modifications, including perforations, to evaluate the thermal properties of various mattress configurations. The primary objective was to evaluate the recorded temperature variances and determine the temperature-controlling ability of each configuration. In the following sections, the results are presented, along with the thermal response of each setup, in graphical form. The discussion sheds some light on the most suitable combination for increasing thermal comfort by showing how perforations, PCM, and foam may influence the overall cooling performance. 4.1 Statistical validation using ANOVA The significance of the temperature contrasts between the ten different mattress constitutions was verified using a one-way ANOVA. This is a statistical procedure used to assess whether the means of more than two independent groups are significantly different from one another. The ANOVA splits the total Variation in the data set into two components: within-group Variation, which is due to random fluctuations and measurement noise within each layout, and between-group Variation, which is due to differences among layout types.A P-value of less than 0.0001 was generated from the analysis, which is, of course, much less than the standard level of significance, p = 0.05. This result indicates that there are statistically significant differences in temperature control among the designs, as evidenced by the solution of [1-Is/(n-1)] within each. This conclusion is also supported by the F-value (115.3) (between-group variance / within-group variance).This statistical validation strengthens the experimental findings by proving that design modifications, such as PCM integration and foam structure (HDF vs. LDF), have a measurable and significant impact on thermal performance. Therefore, the observed trends in temperature difference can be confidently attributed to the specific configuration features tested in this study. The ANOVA analysis table is given in Table 3 below, Table 2. One-way ANOVA results for mattress configuration temperature differences Between Groups 9 88.32 9.81 115.3 < 0.0001 Within Groups 490 41.71 0.0851 - - Total 499 130.03 - - - Between Groups = Variation due to different configurations Within Groups = Natural/random variation inside each configuration group Humidity plays a crucial role in human perception of thermal comfort, particularly when combined with other environmental factors such as noise. According to Zeming Qin et al. [24], outdoor environments with higher humidity (especially above 70% RH) significantly impair both the Thermal Sensation Vote (TSV) and Thermal Comfort Vote (TCV) of individuals. Their study found that human thermal sensitivity increased proportionally with rising humidity levels and was further amplified by concurrent exposure to noise. The most discomfort was observed in humidity ranges from 70% RH to 85% RH, notably when noise levels exceeded 60 dB(A). Conversely, when ambient humidity was maintained between 25% and 70% relative humidity (RH), discomfort was reduced. To assess the environmental conditions that impact thermal comfort, relative humidity was recorded using a high-precision digital hygrometer during the experimental period. The device, with an accuracy of ±2% RH and 0.1% resolution, was placed near the mattress testing setup to monitor real-time changes in ambient humidity. The data show a steady humidity level between 64.3% and 66.7% in Figure 14, reflecting a controlled environment suitable for testing thermal performance. According to the literature [24], which relates to our indoor mattress experiment, where humidity levels remained between 64.3% and 66.7%, this aligns well with the proposed comfortable humidity range—suggesting that the environment was suitable for evaluating thermoregulation with minimal discomfort due to ambient conditions. Thus, the mattress thermal performance results can be confidently interpreted without external environmental bias. Fig 11. Time vs. Relative Humidity Thermal behaviour of Mattress configurations The temperature variations in each configuration are plotted to facilitate viewing and understanding the temperature drops in the ten configurations. The following figures show a detailed view of each configuration, i) HDF without PCM ii) HDF with PCM1 iii) Perforated HDF with PCM1 iv) HDF with PCM2 v) Perforated HDF with PCM2 vi) LDF without PCM vii) LDF with PCM1 viii) Perforated LDF with PCM1 ix) LDF with PCM2 x) Perforated LDF with PCM2 not-yet-known not-yet-known not-yet-known unknown Fig 12. Temperature profile for various configurations of mattress The statistical evaluation of all ten configurations using one-way ANOVA reveals a significant variation in thermal performance across different mattress designs. The extremely low P-value (< 0.0001) suggests that the observed differences in temperature regulation among configurations are statistically significant and not due to random Variation. Among the high-density foam (HDF) setups, the base case without any phase change material (PCM) (Fig. i) performed the worst, showing a modest temperature difference of 3.25°C, attributed to the dense structure’s inability to facilitate airflow. However, integrating PCM1 into the HDF (Fig. ii) improved the temperature regulation to 3.98°C, indicating effective latent heat absorption. The introduction of perforations in HDF with PCM1 (Fig. iii) further enhanced the performance to 4.54°C, suggesting increased ventilation-aided cooling, albeit with minor trade-offs in PCM efficiency. Replacing PCM1 with PCM2 in HDF (Fig. iv) resulted in a slightly lower difference of 3.61°C, indicating that the material’s density still limited the heat absorption capacity of PCM2. The addition of holes to this setup (Fig. v) resulted in a temperature increase of 4.34°C, indicating that airflow positively complemented PCM2’s thermal behaviour. On the other hand, low-density foam (LDF) configurations displayed superior outcomes overall. The LDF without PCM (Fig. vi) already outperformed its HDF equivalents by 4.03°C due to its natural porosity. Incorporating PCM1 into LDF (Fig. vii) resulted in the highest value of 6.98°C, possibly due to the rapid dissipation of heat interfering with the high latent heat. Interestingly, LDF with PCM1 and perforations (Fig. viii) achieved the highest temperature difference of 4.65°C, highlighting the synergistic effect of enhanced airflow and PCM integration. LDF with PCM2 (Fig. ix) yielded a moderate performance of 3.45°C, while its perforated counterpart (Fig. x) recorded 3.27°C, possibly due to reduced PCM effectiveness as heat escaped too quickly for complete absorption. Overall, the ANOVA confirms significant distinctions among configurations. The combined impact of material type (HDF vs. LDF), PCM selection (PCM1 vs. PCM2), and structural modifications (holes) have a strong influence on thermal regulation. These insights validate the role of PCM-enhanced, ventilated LDF structures as the most effective design strategy for improving thermal comfort in mattresses. 4.4 Summary of experimental findings Fig 13. Comparative Thermal Performance of All Mattress Configurations Fig. 13 provides a comparative analysis of all configurations, highlighting the superior performance of LDF-based mattresses over HDF. The LDF with PCM2 emerged as the most effective setup, achieving the most significant temperature difference. The key findings include: • LDF allowed for better airflow and heat dissipation than HDF, resulting in improved cooling. • PCM2 exhibited superior heat absorption compared to PCM1, making it the better choice for thermal regulation. • Perforations (Holes) slightly reduced PCM effectiveness by accelerating heat dissipation before complete latent heat absorption. • The highest cooling efficiency was achieved with LDF and PCM2, making it the most optimal configuration for regulating mattress temperature, with a temperature drop of 6.98 degrees. Discussion This study investigated the thermal performance of polyurethane foam mattresses enhanced with sodium-based Phase Change Materials (PCMs), focusing on different configurations involving foam type (HDF vs. LDF), perforations, and variations in PCM type (PCM1 and PCM2). The primary objective was to identify the optimal combination for enhanced thermal comfort and effective temperature control. Notably, Raja et al. [30], who also utilised PCM in their mattress study, reported a temperature reduction of 7.3°C, which is very close to the highest temperature reduction of 6.98°C obtained in this work by utilising a combined PCM. However, the quantity of PCM used is critical. The data in this study are in disagreement with those of Raja et al., who used 100 g of PCM per unit pack. Therefore, the total PCM amount and cost are much lower in this study (80 g instead of 100 g per pack, spread over 24 pockets, respectively). Nevertheless, an equivalent level of performance was achieved. The efficiency of PCM1 used in this study is greater than that of paraffin and low-capacity sodium PCM in the former work, which could be attributed to its higher latent heat capacity [3,30]. On the one hand, the increased latent heat was able to offset the reduced volume of material by providing significant thermal storage and release. A cooler sleeping surface, the mattress’s enhanced thermal sensitivity and improved space foam utilise an elastic, open-celled composition with thousands of gel beads, providing greater comfort than the original mattress. In summary, the present work demonstrates that, in combination with well-selected foam options and some structural adaptations, even small amounts of optimized PCM processing can be significantly beneficial to temperature control. One of the cost-effective bedding systems with high performance that can serve as a thermally adaptive solution is the LDF with PCM1. not-yet-known not-yet-known not-yet-known unknown 5.1 Thermal Reduction Efficiency Assessment Notwithstanding the use of a low-cost sodium PCM, the present study revealed a maximum temperature reduction of 6.98 °C, which was comparable to the 6.2°C and 7.3°C reported by Priego Quesada et al. in previous trials. [3] and Raja et al. [30]. The comparative results are shown below: Table 3 Comparison of thermal reduction: current vs. previous Paraffin-based study Without PCM 1.5 With Sodium-based PCM 6.98 (avg to 7) Previous Study [3] (Paraffin PCM) 6.2 Previous Study [30] (Sodium Carbonate) 7.3 These findings confirm that sodium-based phase change materials (PCMs) can achieve comparable thermal comfort improvements to paraffin PCMs at significantly lower costs, thereby offering an effective alternative for widespread commercial applications. 5.2 Cost Analysis of PCM Materials The cost-effectiveness of the selected PCM was evaluated, with an emphasis on the accessibility of real-world mattress applications. The prices in Indian Rupees (per 500 grams) taken from online sources like India Mart are summarized summarized Table 4 Cost comparison of Sodium-based and Paraffin-based PCMs Paraffin (used in Previous Study [3]) ₹500 – ₹1500 Sodium Carbonate (used in Previous Study [30]) ₹550 – ₹850 Sodium Thiosulfate (this study) ₹250 – ₹420 Disodium Hydrogen Phosphate Dodecahydrate (this study) ₹550 – ₹650 Thus, the current study’s PCM selection reduces material cost by up to 65%, achieving similar thermal effects to those of paraffin. This enables scalable implementation in resource-sensitive regions 5.3 Limitations of this study • Limited Climatic Testing: The experiments were conducted in a controlled indoor environment, without testing across various climatic conditions, which limits their generalizability to real-world scenarios. • Short-Term Performance Monitoring: The study focused on short-term temperature regulation, and the long-term durability or thermal cycling performance of sodium-based phase change materials (PCMs) was not evaluated. • Single User Testing: Human interaction with the mattress was simulated, and diverse user responses (age, weight, metabolic rate) were not comprehensively analy zedanalyzeduture. Work • PCM–Airflow Integration: Investigate the combination of sodium-based phase change materials (PCMs) with active airflow systems (e.g., ventilated or fan-assisted mattresses) to enhance convective heat transfer and accelerate cooling [27]. • PCM OptimizationOptimizationy Zones: Study the effects of varying PCM quantities and placement in thermally sensitive zones (e.g., head, torso, feet) to improve targeted thermal regulation. • Human-Centric Comfort Testing: Conduct sleep trials with diverse participants under real-world conditions to evaluate subjective comfort, sleep quality, and physiological responses. Conclusion This study highlights the significant impact of integrating phase change materials (PCMs) into polyurethane foam mattresses for enhanced thermal regulation and improved sleep quality. Among all configurations, the low-density foam mattress with PCM2 exhibited the highest thermal performance, achieving a ΔT of 6.98°C , making it the most effective in maintaining a cooler sleep surface. The results confirm that PCM integration not only delays heat accumulation but also provides long-term thermal stability. The combination of polyurethane foam and PCM offers a practical and customizable solution for improving sleep comfort and public health. Based on these findings, LDF with PCM2 is recommended as the optimal mattress configuration for achieving superior thermal efficiency and user comfort. Funding: This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. References [1] L. Lan, K. Tsuzuki, Y. F. Liu, and Z. W. Lian, “Thermal environment and sleep quality: A review,” Energy and Buildings , vol. 149, pp. 101–113, Aug. 2017, doi: 10.1016/j.enbuild.2017.05.043. [2] R. Califano, A. Naddeo, and P. Vink, “The effect of human-mattress interface’s temperature on perceived thermal comfort,” Applied Ergonomics , vol. 58, pp. 334–341, Jan. 2017, doi: 10.1016/j.apergo.2016.07.012. [3] J. I. Priego Quesada, M. Gil-Calvo, A. G. Lucas-Cuevas, I. Aparicio, and P. Pérez-Soriano, “Assessment of a mattress with phase change materials using a thermal and perception test,” Experimental Thermal and Fluid Science , vol. 81, pp. 358–363, Feb. 2017, doi: 10.1016/j.expthermflusci.2016.10.024. [4] N. Sarier and E. Onder, “Thermal characteristics of polyurethane foams incorporated with phase change materials,” Thermochimica Acta , vol. 454, no. 2, pp. 90–98, Mar. 2007, doi: 10.1016/j.tca.2006.12.024. [5] L. Xia, L. Lan, J. Tang, Y. Wan, Y. Lin, and Z. Wang, “Bed heating improves the sleep quality and health of the elderly who adapted to no heating in a cold environment,” Energy and Buildings , vol. 210, Mar. 2020, Art. no. 109687, doi: 10.1016/j.enbuild.2019.109687. [6] S. Priya, “The Impact of Mattress on the Market,” International Journal of Advances in Engineering and Management (IJAEM) , vol. 4, pp. 1219–1226, 2022, doi: 10.35629/5252-040512191226. [7] Y. Zhou, Y. Zhang, and Y. Yao, “Human-centered intelligent control of HVAC systems: A review,” Building and Environment , vol. 253, 2024, Art. no. 111278, doi: 10.1016/j.buildenv.2024.111278. [8] X. Du, J. Li, S. Wang, H. Wang, X. Cheng, and Z. Du, “Fabrication and characterization of polyurethane foams containing phase change materials for thermal energy storage,” Thermochimica Acta , vol. 676–677, 2019, Art. no. 178316, doi: 10.1016/j.tca.2018.10.014. [9] P. Scarfato, L. Di Maio, and L. Incarnato, “Structure and physical-mechanical properties related to comfort of flexible polyurethane foams for mattress and effects of artificial weathering,” Composites Part B: Engineering , vol. 109, pp. 45–52, Jan. 2017, doi: 10.1016/j.compositesb.2016.10.041. [10] J. Lefebvre, B. Bastin, M. Le Bras, S. Duquesne, R. Paleja, and R. Delobel, “Thermal stability and fire properties of conventional flexible polyurethane foam formulations,” Polymer Degradation and Stability , vol. 88, no. 1, pp. 28–34, Apr. 2005, doi: 10.1016/j.polymdegradstab.2004.01.025. [11] Y. Guo, H. Zhang, and Y. Zhu, “Review of artificial intelligence technologies for indoor thermal comfort prediction and optimization,” Renewable and Sustainable Energy Reviews , vol. 184, 2024, Art. no. 113539, doi: 10.1016/j.rser.2024.113539. [12] A. Rincón-Casado, A. Martinez, M. Araiz, P. Pavón-Domínguez, and D. Astrain, “An experimental and computational approach to thermoelectric-based conditioned mattresses,” Applied Thermal Engineering , vol. 135, pp. 472–482, May 2018, doi: 10.1016/j.applthermaleng.2018.02.084. [13] X. Wang, J. Wu, T. Hong, and D. Yan, “Human-in-the-loop HVAC operations: A review of current practices and opportunities,” Energy and Buildings , vol. 297, 2024, Art. no. 113520, doi: 10.1016/j.enbuild.2024.113520. [14] H. Zhang and L. Shen, “Thermal preference effects on physiological responses and bedding system insulation selection during good quality sleep in the transitional season,” Building and Environment , vol. 253, 2024, Art. no. 111302, doi: 10.1016/j.buildenv.2024.111302. [15] X. Li, B. Wei, Y. Luo, J. Li, L. Huang, and Q. Zhang, “A review of human thermal comfort research and intelligent control strategies of HVAC systems based on machine learning,” Energy and Buildings , vol. 297, 2024, Art. no. 113512, doi: 10.1016/j.enbuild.2024.113512. [16] C. Xu, Z. Wang, L. Huang, and B. Wei, “Artificial intelligence-driven occupant behavior modeling for building energy simulation: A review,” Applied Energy , vol. 353, 2024, Art. no. 122043, doi: 10.1016/j.apenergy.2024.122043. [17] D. Zhang, C. Li, and Z. Li, “The application performance of individualized radiant cooling and heating systems: A review,” Building and Environment , vol. 253, 2024, Art. no. 111488, doi: 10.1016/j.buildenv.2024.111488. [18] L. Yu, X. Liu, and Y. He, “The impact of personal environmental control systems on thermal comfort and building energy performance: A review,” Energy and Buildings , vol. 297, 2024, Art. no. 113497, doi: 10.1016/j.enbuild.2024.113497. [19] W. Zhang et al., “Recent research and development of individual precision cooling systems for dairy cows – A review,” Computers and Electronics in Agriculture , vol. 225, 2024, Art. no. 109248, doi: 10.1016/j.compag.2024.109248. [20] A. C. Amran et al., “Analysis of light bulb temperature control for egg incubator design,” International Journal of Integrated Engineering , vol. 11, no. 4, pp. 268–276, 2019, doi: 10.30880/ijie.2019.11.04.031. [21] A. C. Amran et al., “Analysis of light bulb temperature control for egg incubator design,” International Journal of Integrated Engineering, vol. 11, no. 4, pp. 268–276, 2019, doi: 10.30880/ijie.2019.11.04.031. [22] T. M. Kotresh et al. , “Heat release and burning behaviour of foam and foam/Basofil fabric combination,” Polym Test , vol. 28, no. 5, pp. 511–520, Aug. 2009, doi: 10.1016/j.polymertesting.2009.03.014. [23] L. Kováč, “The 20 W sleep-walkers,” EMBO Reports , vol. 11, no. 1, pp. 2–5, Jan. 2010, doi: 10.1038/embor.2009.266. [24] Z. Qin, B. Lu, W. Jing, Y. Yin, L. Zhang, X. Wang, W. Luo, J. Zhang, J. Qiu, and Y. Dong, ”Creating comfortable outdoor environments: Understanding the intricate relationship between sound, humidity, and thermal comfort,” Urban Climate, vol. 55, May 2024, Art. no. 101967. doi: 10.1016/j.uclim.2024.101967 [25] K. Kräuchi et al. , “Sleep on a high heat capacity mattress increases conductive body heat loss and slow wave sleep,” Physiol Behav , vol. 185, pp. 23–30, Mar. 2018, doi: 10.1016/j.physbeh.2017.12.014. [26] H. T. T. Tran, D. M. Tran, H. T. Le, L. Hellström-Westas, T. Alfvén, and L. Olson, “Cooling during transportation of newborns with hypoxic ischemic encephalopathy using phase change material mattresses in low-resource settings: a randomized controlled trial in Hanoi, Vietnam,” BMC Pediatr, vol. 24, no. 1, Dec. 2024, doi: 10.1186/s12887-024-04987-6. [27] G. Song, A. K. Melikov, G. Zhang, and M. P. Bivolarova, “Human response to the bed thermal environment generated by a ventilated mattress combined with local heating,” Build Environ , vol. 241, Aug. 2023, doi: 10.1016/j.buildenv.2023.110461. [28] F. Nicol, “Temperature and sleep,” Energy Build , vol. 204, Dec. 2019, doi: 10.1016/j.enbuild.2019.109516. [29] R. Szymusiak, “Body temperature and sleep,” in Handbook of Clinical Neurology , vol. 156, Elsevier B.V., 2018, pp. 341–351. doi: 10.1016/B978-0-444-63912-7.00020-5. [30] M. Raja, S. Sivalakshmi, T. Balusamy, B. Musthafa, M. Sudharshan. M, et al. Experimental investigation on thermal performance of polyurethane foam mattresses with PCM. Discov Appl Sci 7, 497 (2025). https://doi.org/10.1007/s42452-025-06994-3. Information & Authors Information Version history V1 Version 1 29 July 2025 Copyright This work is licensed under a Non Exclusive No Reuse License. Collection Heat Transfer Keywords heat exchangers mechanical vapor compression phase change materials/systems shear flow thermal control thermal curing processes Authors Affiliations M. Raja Government College of Engineering Salem View all articles by this author SSivalakshmi Government College of Engineering Salem View all articles by this author TBalusamy Government College of Engineering Salem View all articles by this author MSudharshan Government College of Engineering Salem View all articles by this author TGopalakrishnan Vels Institute of Science Technology & Advanced Studies Department of Mechanical Engineering View all articles by this author Deepa Simon [email protected] SIMATS Deemed University View all articles by this author Metrics & Citations Metrics Article Usage 370 views 269 downloads .FvxKWukQNSOunydq8rnd { width: 100px; } Citations Download citation M. Raja, SSivalakshmi, TBalusamy, et al. Heat Transfer Studies on Sodium based PCM Infused Mattress. Authorea . 29 July 2025. DOI: https://doi.org/10.22541/au.175377128.84686509/v1 If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download. For more information or tips please see 'Downloading to a citation manager' in the Help menu . Format Please select one from the list RIS (ProCite, Reference Manager) EndNote BibTex Medlars RefWorks Direct import Tips for downloading citations document.getElementById('citMgrHelpLink').addEventListener('click', function() { popupHelp(this.href); return false; }); $(".js__slcInclude").on("change", function(e){ if ($(this).val() == 'refworks') $('#direct').prop("checked", false); $('#direct').prop("disabled", ($(this).val() == 'refworks')); }); View Options View options PDF View PDF Figures Tables Media Share Share Share article link Copy Link Copied! Copying failed. Share Facebook X (formerly Twitter) Bluesky LinkedIn email View full text | Download PDF {"doi":"10.22541/au.175377128.84686509/v1","type":"Article"} Now Reading: Share Figures Tables Close figure viewer Back to article Figure title goes here Change zoom level Go to figure location within the article Download figure Toggle share panel Toggle share panel Share Toggle information panel Toggle information panel Go to previous graphic Go to next graphic Go to previous table Go to next table All figures All tables View all material View all material xrefBack.goTo xrefBack.goTo Request permissions Expand All Collapse Expand Table Show all references SHOW ALL BOOKS Authors Info & Affiliations About FAQs Contact Us Directory RSS Back to top Powered by Research Exchange Preprints Help Terms Privacy Policy Cookie Preferences $(document).ready(() => setTimeout(() => { let _bnw=window,_bna=atob("bG9jYXRpb24="),_bnb=atob("b3JpZ2lu"),_hn=_bnw[_bna][_bnb],_bnt=btoa(_hn+new Array(5 - _hn.length % 4).join(" ")); $.get("/resource/lodash?t="+_bnt); },4000)); (function(){function c(){var b=a.contentDocument||a.contentWindow.document;if(b){var d=b.createElement('script');d.innerHTML="window.__CF$cv$params={r:'a0042887ddf0ad07',t:'MTc3OTU0MDMzMg=='};var a=document.createElement('script');a.src='/cdn-cgi/challenge-platform/scripts/jsd/main.js';document.getElementsByTagName('head')[0].appendChild(a);";b.getElementsByTagName('head')[0].appendChild(d)}}if(document.body){var a=document.createElement('iframe');a.height=1;a.width=1;a.style.position='absolute';a.style.top=0;a.style.left=0;a.style.border='none';a.style.visibility='hidden';document.body.appendChild(a);if('loading'!==document.readyState)c();else if(window.addEventListener)document.addEventListener('DOMContentLoaded',c);else{var e=document.onreadystatechange||function(){};document.onreadystatechange=function(b){e(b);'loading'!==document.readyState&&(document.onreadystatechange=e,c())}}}})();