Hydrogen-Enhanced Efficiency of LPG Central Heating Boilers

Hydrogen-Enhanced Efficiency of LPG Central Heating Boilers | 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 Hydrogen-Enhanced Efficiency of LPG Central Heating Boilers Kypros Demetriou, Christina Christodoulou, Christodoulos Christodoulou, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4643106/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract The search for sustainable energy solutions has led to new approaches in various industrial sectors, including combustion systems. The present study represents a detailed investigation for the potential improvement of an LPG burner/Boiler efficiency by adding a stoichiometric mixture of hydrogen and oxygen (HHO gas) in the main fuel. The study included observation of the quality of the flame and its temperature profile without and with the introduction of HHO gas in an open-side/end combustion tube. It also included the construction of a laboratory scale LPG Burner/Boiler with a water tank and its operation without and with the introduction of the HHO gas in the LPG burner. Diagrams of water temperature and theoretical heat input as a function of time were used to compare the Boilers efficiency without and with the introduction of the HHO in the LPG burner. The study proved that adding HHO gas to the combustion process can significantly enhance fuel efficiency at least by 10% while reducing exhaust gas emissions by > 80% the Unburned Hydrocarbons (UH) and by > 50% the Carbon Monoxides (CO). The results of the use of such hydrogen technologies are very promising for enhancing efficiencies in sustainable combustion technologies and for promoting environmental stewardship not only for Boilers but potentially for gas-turbines and Ships/Heavy Trucks/Generators Internal Combustion Engines (ICE) in industrial applications as well as road and maritime transportation. Hydrogen technologies HHO gas fuel savings boiler efficiency reduction of exhaust gas emissions Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 1. Introduction The need for sustainable energy solutions in industrial processes has led to research into new methods to improve efficiency while reducing environmental impact. According to J.M. Babu et al [ 1 ] and Ruggero Maria Santilli [ 2 ] one promising method is the use of HHO gas, a stoichiometric mixture of hydrogen and oxygen produced through electrolysis, in combustion systems as study by Balaji Subramanian et al. [ 3 ]. This study aims to explore how adding HHO gas to gas burners can make them more efficient and reduce emissions as shown by Tamer Nabil et al. [ 4 ]. The idea is that by introducing HHO gas into an LPG stream, one can improve burner efficiency (Ammar A. Al-Rousan [ 5 ]), leading to a more complete LPG combustion while emitting fewer pollutants. To test this idea, a systematic research plan was developed, including setting-up experiments, collecting data and analyzing the results. During the experiments, precise control over the flow of HHO gas into the combustion process was achieved using an ON/OFF switch and safety devices (back-flash arrestors). This allowed for precise adjustments to ensure safety and consistency. Initially, the gas burner was operated on pure LPG to establish its baseline performance, followed by abrupt addition of HHO gas to observe its effects on combustion according to M. Aravindan et al. [ 6 ]. Additionally, variations in HHO gas flow rates were explored to find the best operating parameters. A crucial part of this research methodology was collecting data regularly, including temperature measurements, fuel flow rates, and HHO gas consumption (Arul Murugan et al. [ 7 ]). This data forms the basis for quantitative analysis, helping to identify trends and correlations indicative of the impact of HHO gas addition on burner efficiency. Advanced tools such as infrared cameras and gas analyzers are used to study flame characteristics and emissions profiles in detail. In summary, the present study proposes a new approach to improve gas burner efficiency through the strategic use of HHO gas. By understanding the mechanisms behind this enhancement, the study aimed to contribute to the advancement of sustainable combustion technologies and emphasize the importance of environmental stewardship in industrial processes as mentioned by Sa’ed A. Musmar et. Al. [ 8 ]. 2. Design, Construction and Operation of an Open-Side/End SS Tube The experimental setup aimed to analyze the combustion characteristics of both Liquefied Petroleum Gas (LPG) and Hydrogen-Enriched LPG (HHO) systems, with a focus on understanding their performance efficiency and emissions profiles (Usman et al [9)]. Central to this setup is the use of an LPG tank as the main fuel source, providing a stable fuel base for combustion experiments. Coupled with a commercial LPG burner equipped with adjustable flame control capabilities, this setup allows for precise regulation of LPG flow and flame intensity, ensuring controlled combustion conditions necessary for accurate experimentation (Adam J. Gee et al. [ 10 ]). Two HHO generators were also included in the setup, introducing a mixture of hydrogen and oxygen into the system. This addition presents a new element, offering the opportunity to investigate the combustion dynamics and efficiency of this HHO additive hydrogen technology (Zhe Zhao et al. [ 11 ]). In order to comprehensively assess the performance and characteristics of LPG and HHO combustion systems, a multifaceted monitoring approach has been carefully designed. Key to this approach were strategically placed gas flow meters, which accurately measure the flow rates of both LPG and HHO. These devices provide valuable data regarding the mass/volume of gases entering the combustion chamber, allowing for a deeper understanding of the combustion process. Additionally, an array of thermocouples has been strategically positioned throughout the system to monitor flame temperatures. By capturing temperature profiles at critical points, this setup enables one to gain insights into the thermal dynamics during the entire combustion cycle and access combustion efficiencies. Furthermore, a gas analyzer has been integrated into the system in order to obtain exhaust gas emissions. This sophisticated instrument examines combustion by-products, ensuring a comprehensive evaluation of combustion performance. Gas emissions such as CO and UH were measured to understand the environmental impact of both LPG and HHO combustion (Gregory Sherman et al. [ 12 ]). Together, this integrated monitoring system enables one to conduct a thorough analysis to optimize combustion processes and contribute to a more efficient and environmentally conscious utilization of LPG and HHO. During the experiments, safety precautions were put in place to protect both personnel and equipment. This involved ensuring there were fire extinguishing equipment readily available to deal with any unexpected fires. The experiments were conducted in a controlled environment equipped with proper ventilation systems to reduce the risk of gas build-up and manage potential by-products effectively. In the initial stages of the study, focus was on establishing the infrastructure necessary to perform the experiments precisely and safely. This involved the design and construction of an open-side/end stainless-steel tube fitted with an LPG burner, which served as the cornerstone of the investigation (as shown in Fig. 1 ). The tube, measuring 2 meters in length, 17 centimeters in diameter, and 3 mm thickness, was crafted with precision to ensure both durability and resistance to corrosion, vital for the extended duration of the study. Key to this setup was the integration of the Baltur BTG-3 LPG burner, renowned for its adaptability and efficient utilization of LPG at 30 mbar pressure, with a power range spanning from 16.6 to 42.7 kW. To facilitate accurate temperature monitoring, high-temperature J-type thermocouples were strategically placed at intervals of 20–25 cm along the tube. Additionally, to ensure comprehensive data collection, a gas flow meter, a precision mass balance and a Pico DAQ system were used. 2.1 Temperature Profiles along the open-side/end SS tube The impact of introducing HHO gas on the performance of an open-side/end stainless steel tube equipped with an LPG burner (see Fig. 1 ) was investigated, aiming to gather qualitative insights into combustion. This analysis focused on several key parameters to observe any noticeable changes. Initially, the flame color was closely observed, specifically looking for any transition from its typical yellowish color to blueish upon the introduction of HHO gas. Furthermore, the flame temperature was recorded, comparing readings between scenarios without and with HHO gas to identify any differences. Additionally, examination extended to the preliminary assessment of emissions, particularly the levels of Unburned Hydrocarbons (UH) and Carbon Monoxide (CO) in the exhaust gases. These findings contribute to a deeper understanding of the potential effects of HHO gas supplementation on combustion processes, offering valuable insights for further research and application in various industrial applications. Figure 2 shows the thermal images of the flames without (left image) and with the introduction of HHO gas into LPG burners (right image). HHO gas, a blend of hydrogen and oxygen, offers distinct advantage due to its higher flame speed. This promotes improved combustion characteristics and higher heat-generated compared to using LPG alone. By introducing HHO gas alongside LPG, the combustion process becomes more efficient, leading to better utilization of fuel and more heat generated. This synergy between HHO gas and LPG shows a potential for enhancing the performance of burners across various applications, highlighting its potential to contribute to cleaner and more effective combustion processes. Furthermore, Fig. 3 shows the Temperature profiles inside the SS tube without HHO gas and after the introduction of the HHO gas. Due to higher efficiency, more heat is generated and the corresponding temperatures are higher in the case of the introduction of the HHO gas. 2.2 Qualitative Flame Observation in an Open-side/end tube Figure 4 shows the quality of the flame without and with the HHO gas. The pure LPG flame appears yellowish blur, suggesting an incomplete combustion reaction. In contrast, with HHO gas, the LPG + HHO flame becomes blueish-clean, indicative of complete combustion. This scenario also exhibits higher temperatures along the SS tube in comparison to using LPG alone as shown previously in Fig. 3 . Additionally, in the case of HHO gas, the flame appears shorter due to its enhanced flame velocity completing the combustion process faster, thus shortening the flame-combustion length. These observations underscore the role of HHO in promoting cleaner combustion and elevating thermal dynamics within the SS tube setup. At the same time, preliminary exhaust gas emissions’ analyses indicated much less Unburned Hydrocarbons (UH) and Carbon Monoxides (CO), something that was further investigated qualitatively during the experiments on the boiler. 3. Design, Construction and Operation of HHO Generators and a Laboratory-scale LPG burner-based boiler 3.1 Design and Construction of HHO Generators Two HHO Generators were designed, constructed and operated. The first ( HHO1 ) (shown in Fig. 5 and Fig. 7 ) was designed based on a 90DCV Power Supply with a maximum current output of 16.6 Amperes (total of 1500Watt power). The second one ( HHO2 ) (shown in Fig. 6 and Fig. 8 ) was designed based on a 28.7DCV Power Supply with a maximum current output of 52 Amperes (total of 1500Watt power) [ 17 ]. The electrolytic cells designed for HHO generation integrate various components to allow controlled gas production. Stainless steel electrodes are used and submerged in a solution of deionized water and electrolyte, usually potassium hydroxide (KOH). Before experimentation, the electrolyte concentration is adjusted to achieve the desired HHO gas output while reducing energy consumption. A variable DC power supply provides the necessary voltage and current, starting electrolysis and breaking down water into stoichiometric hydrogen and oxygen gases. The resulting HHO gas flows through two water-bubblers to remove impurities and ensure purity. The HHO gas is instantly pre-mixed with LPG in the pre-mixing chamber of the burner. The gas pre-mixing system includes flow control valves, allowing precise regulation of both LPG and HHO for optimal instant blending before combustion. The mixing ratio of HHO and LPG can be adjusted according to specific requirements and application needs. This comprehensive setup allows for the customization and controlled deployment of such HHO mixtures, providing efficient and versatile energy solutions for existing conventional industrial/residential gas-boilers. 3.2 Design and Construction of a Laboratory-scale LPG burner-based boiler The laboratory-scale LPG burner-based boiler (shown in Fig. 9 ) design underscores safety, efficiency, and performance for experimental pursuits, particularly in capturing dynamic heating capacity. Detailed attention was devoted to construction, employing a robust insulated copper water tank to ensure both pressure resilience and heat retention, complemented by the reliable Baltur BTG 3 LPG burner kit for enduring performance. The burner was connected to the boiler which was interconnected to the water tank through insulated copper pipes for secure and efficient connections. A water-pump was used to directly circulate the boiler’s water into the water tank. Safety remains paramount, with multiple features incorporated to safeguard against potential hazards, including pressure relief valves, expansion tanks, thermocouples for temperature monitoring, and emergency shut-off mechanisms. The control system was equipped with precision pressure and temperature gauges (shown in Fig. 10 ) to ensure a safe and seamless operation. Experimental procedures encompass a comprehensive examination of parameters such as heating capacity and exhaust gas emissions (CO and UH), with a specific focus on evaluating system’s thermal efficiency and the environmental impact of HHO gas additions. 3.3 Results and Discussion on a Laboratory-scale LPG burner-based boiler The Boiler/LPG burner was initially operated with LPG alone recording the Inlet and Outlet water Temperature and the total instant Thermal Input of LPG fuel as a function of time, as shown in Fig. 9 . The water Temperatures were recorder using the J-type thermocouples installed in the Inlet and Outlet of the water tank. The total instant Thermal Input of LPG fuel was calculated by recording the total instant mass of the LPG consumed and the Lower Calorific Value (46.1312MJ/kg LPG) of the LPG having a molecular composition of 70%Propane and 30% Butane. The efficiency of the boiler running on LPG is proportional to the Temperature gradient (dT/dt = 0.02363) of the Inlet water tank temperature profile and inverse proportional to the total instant Thermal Input gradient of LPG (dH/dt = 0.01551), as shown in Fig. 10 . Therefore, the efficiency of the boiler running on LPG is proportional to 0.02363/0.01551 = 1.5235. Consequently, the Boiler/LPG burner was operated with LPG and the introduction of HHO gas continuing recording the Inlet and Outlet water Temperature and the total instant Thermal Input of LPG fuel as a function of time, as shown in Fig. 9 . The water Temperatures and total instant Thermal Input of (LPG + HHO) fuel were also calculated similarly. The contribution of HHO gas in the total instant Thermal Input was calculated by recording the total instant mass of the H 2 in the HHO mixture consumed and the Lower Calorific Value of 119.94MJ/kg of H 2 . The efficiency of the boiler running on LPG + HHO is proportional to the Temperature gradient (dT/dt = 0.02987) of the Inlet water tank temperature profile and inverse proportional to the total instant Thermal Input gradient of LPG + HHO (dH/dt = 0.01779), as shown in Fig. 10 . Therefore, the efficiency of the boiler running on LPG is proportional to 0.02987/0.01779 = 1.6790. The ratio of the efficiencies with HHO and to without HHO gas is calculated to be 1.6790/1.5235 = 1.102. In other words, the introduction of HHO gas in the LPG increases the thermal efficiency of the boiler by about 10%. Additionally, the reduction of exhaust gas emissions, particularly Unburned Hydrocarbons (UH) and Carbon Monoxide (CO), were quantitatively measured without and with the introduction of HHO gas into the combustion process by using gas analyzers, at the end of each mode of operation (LPG or LPG + HHO), as indicated in Fig. 9 . The results revealed a remarkable reduction in gas-emissions with the introduction of HHO gas. Specifically, there was an 81% decrease in unburned hydrocarbons (UH) and a 53% decrease in carbon monoxide (CO), as shown in Figs. 11 – 12 , correspondingly. These findings underscore the effectiveness of HHO gas in enhancing combustion efficiency and mitigating harmful emissions, highlighting its potential role in promoting environmental sustainability and air quality improvements. 4. Conclusions Through a systematic study, the introduction of HHO gas into an LPG burner/boiler showed a notable 10% increase in thermal efficiency. In addition, integrating HHO gas led to substantial reductions in exhaust gas emissions, with an impressive 81% decrease in unburned hydrocarbons (UH) and a 53% reduction in Carbon Monoxide (CO) in agreement with Mohamed M. et al. [ 13 ], N. Yuca et. al. [ 14 ] and Shuofeng Wang et al. [ 15 ] who reported similar improvements in emission’s reductions. The results of the use of such HHO technologies are very promising for enhancing efficiencies in sustainable combustion technologies and for promoting environmental stewardship not only for Boilers but potentially for gas-turbines and Ships/Heavy Trucks/Generators’ Internal Combustion Engines (ICE) in industrial applications as well as road [ 16 ] and maritime transportation. Similar results were obtained by Ch. Christodoulou [ 17 – 18 ] for HHO application on Buses and Vans where fuel savings of 5–25% and exhaust gas emissions’ reductions of more than 20% were achieved. Declarations Author Contribution Dear Editor-in-Chief,All authors whose names appear on the submission,1. made substantial contributions to the conception or design of the work; or the acquisition, analysis, or interpretation of data; or the creation of new software used in the work;2. drafted the work or revised it critically for important intellectual content;3. approved the version to be published; and4. agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. Data Availability Dear Editor-in-Chief,The full set of data that support the findings of this study are available from the corresponding author, George N Karagiorgis ( [email protected] ), upon reasonable request. The data are not publicly available due to restrictions in, confidentiality. Interested researchers can contact the corresponding author to request access to the data.Furthermore, please note that the final results of this study, are properly presented as figures in the paper. References J.M. Babu, K. Sunil Kumar, R. Ramesh Kumar, Ümit Ağbulut, Abdul Razak, Deepak Thakur, Vikram Sundara, Mohammad Asif, “Production of HHO gas in the water-electrolysis unit and the influences of its introduction to CI engine along with diesel-biodiesel blends at varying injection pressures”, International Journal of Hydrogen Energy, Vol. 52, Part D (2024) 865-885 Ruggero Maria Santilli, “A new gaseous and combustible form of water”, International Journal of Hydrogen Energy, Vol. 31, Issue 9, (2006) 1113-1128 Balaji Subramanian, Saleel Ismail, “Production, and use of HHO gas in IC engines”, International Journal of Hydrogen Energy, Vol. 43, Issue 14 (2018) 7140-7154 Tamer Nabil, Mohamed M. Khairat Dawood, “Enabling efficient use of oxy-hydrogen gas (HHO) in selected engineering applications; transportation and sustainable power generation”, Journal of Cleaner Production, Vol. 237 (2019) 117798 Ammar A. Al-Rousan, “Reduction of fuel consumption in gasoline engines by introducing HHO gas into intake manifold”, International Journal of Hydrogen Energy, Vol.35, Issue 23 (2010) 12930-12935 M. Aravindan, K. Madhesh, G. Praveen Kumar, Madhan K. Arulanandam, Srinath Murali, Neelam Sheoran, Nirmal Waykole, Rajmohan Muthaiah, Pawan Sharma, Asheesh Anand, “Computational and Chemical Kinetics Analysis of Hydrogen-Blended LPG for Domestic Cook Stove Burners”, Energy Conversion and Management, Vol.22 (2024) 100568 Arul Murugan, Marc de Huu, Thomas Bacquart, Janneke van Wijk, Karine Arrhenius, Indra te Ronde, David Hemfrey, “Measurement challenges for hydrogen vehicles”, International Journal of Hydrogen Energy, Vol.44, Issue 35 (2019) 19326-19333 Sa’ed A. Musmar, Ammar A. Al-Rousan, “Effect of HHO gas on combustion emissions in gasoline engines”, Fuel, Vol.90, Issue10 (2011) 3066-3070 Muhammad & Naqvi, Muhammad & Saleem, Muhammad Wajid & Hussain, Jafar & Raza Naqvi, Salman & Jahangir, Shahzaib & Usama, Muhammad & Idrees, Saad & Anukam, Anthony, “Use of Gasoline, LPG and LPG-HHO Blend in SI Engine”, Special Issue: Progress in Energy Conversion Systems and Emission Control, Processes, 8(1), 74 (2020) 1-15 Adam J. Gee, Douglas B. Proud, Neil Smith, Alfonso Chinnici, Paul R. Medwell, “Hydrogen addition to a commercial self-aspirating burner and assessment of a practical burner modification strategy to improve performance”, International Journal of Hydrogen Energy, Vol.49, Part B (2024) 59-76 Zhe Zhao, Yan Huang, Xiumin Yu, Ping Sun, Ming Li, Weibo Shi, Zezhou Guo, Tianqi Wang, “Effect of HHO addition on combustion and emission in SI engine with butanol direct injection and gasoline port injection”, Case Studies in Thermal Engineering, Vol. 42 (2023) 102746 Gregory Sherman, Amit Pratap Singh, “Fuel efficiency and emissions reduction of hydroxy added gasoline fuel using HydroBoost technology”, International Journal of Hydrogen Energy, Vol. 48, Issue 38 (2023) 14511-14526 Amer Nabil, Mohamed M. Khairat Dawood, “Enabling efficient use of oxy-hydrogen gas (HHO) in selected engineering applications; transportation and sustainable power generation”, Journal of Cleaner Production, Vol. 237 (2019) 117798 Y. Karagöz, N. Yuca, T. Sandalcı, A.S. Dalkılıç, “Effect of hydrogen and oxygen addition as a mixture on emissions and performance characteristics of a gasoline engine”, International, Journal of Hydrogen Energy, Vol. 40, Issue 28 (2015) 8750-8760 Shuofeng Wang, Changwei Ji, Bo Zhang, Xiaolong Liu, “Performance of a hydroxygen-blended gasoline engine at different hydrogen volume fractions in the hydroxygen”, International Journal of Hydrogen Energy, Vol. 37, Issue 17 (2012)13209-13218 “Integration of innovative green technologies on existing public transportation buses for 5% to 30% fuel saving” BUS-FUEL-SAVING, INTEGRATED/0916/0031,2019-2022 Christina Ch. Christodoulou, “Fuel Savings and Reduction of Exhaust Gas Emissions by Application of HHO Technologies on Existing Internal Combustion Engine (ICE) Vehicles” 7th Int. Conf. on RES & Energy Efficiency, Nicosia, Oct 12-14, 2023 Christina Ch. Christodoulou, “Fuel Savings and Reduction of Exhaust Gas Emissions by Application of HHO Technologies on Existing Internal Combustion Engine (ICE) Vehicles”, 3rd Doctoral Colloquium of the Cyprus Rectors’ Conference, Nicosia, April 13, 2024 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted 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-4643106","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":333806294,"identity":"df223cd6-045c-4008-9a25-fb43c1b98483","order_by":0,"name":"Kypros Demetriou","email":"","orcid":"","institution":"Frederick University","correspondingAuthor":false,"prefix":"","firstName":"Kypros","middleName":"","lastName":"Demetriou","suffix":""},{"id":333806295,"identity":"efc55e16-52b1-4e4b-a3cb-eaf8dd30c0d2","order_by":1,"name":"Christina Christodoulou","email":"","orcid":"","institution":"Frederick 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4","display":"","copyAsset":false,"role":"figure","size":292740,"visible":true,"origin":"","legend":"\u003cp\u003eFlame quality before (a) and after (b) introduction of HHO in an LPG Burner\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-4643106/v1/c3ca9b970ea4487e6ffab1e0.png"},{"id":61646674,"identity":"dac8630e-c1dc-4c96-9413-6433b5bae01a","added_by":"auto","created_at":"2024-08-02 11:20:11","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":275301,"visible":true,"origin":"","legend":"\u003cp\u003eHHO1 Generator consisting of 3-Stacks of 40-Plates each operating at 90DCV and maximum current of 16.6A (1500 Watt)\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-4643106/v1/33dd87a6356969aab9fdf1f2.png"},{"id":61646289,"identity":"bcf8da3d-fc74-48bc-bff1-6527723e1fa9","added_by":"auto","created_at":"2024-08-02 11:12:12","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":328889,"visible":true,"origin":"","legend":"\u003cp\u003ePicture of the HHO2 Generator consisting of two parallel 5-Stacks of 13-Plates each operating at 27.6DCV and maximum current of 55A (1500 Watt)\u003c/p\u003e","description":"","filename":"6.png","url":"https://assets-eu.researchsquare.com/files/rs-4643106/v1/c32651f28bcd22a00c76df2b.png"},{"id":61646675,"identity":"4928fcd9-f376-4f4b-bb7f-47313d43a01c","added_by":"auto","created_at":"2024-08-02 11:20:11","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":365170,"visible":true,"origin":"","legend":"\u003cp\u003ePicture of the constructed HHO1 Generator System consisting of 3-Stacks of 40-Plates each operating at 90DCV and maximum current of 16.6A (1500 Watt)\u003c/p\u003e","description":"","filename":"7.png","url":"https://assets-eu.researchsquare.com/files/rs-4643106/v1/e3eaebd3b64310d05e93f2de.png"},{"id":61645614,"identity":"45a542df-733a-4d04-9f05-4be778037eef","added_by":"auto","created_at":"2024-08-02 11:04:12","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":503914,"visible":true,"origin":"","legend":"\u003cp\u003ePicture of the HHO2 Generator System consisting of two parallel 5-Stacks of 13-Plates each operating at 27.6DCV and maximum current of 55A (1500 Watt)\u003c/p\u003e","description":"","filename":"8.png","url":"https://assets-eu.researchsquare.com/files/rs-4643106/v1/a20e6fc8f1fac9601ffa66d5.png"},{"id":61645610,"identity":"79ad6bf9-519b-4800-95d0-84b921b9f8c2","added_by":"auto","created_at":"2024-08-02 11:04:12","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":419551,"visible":true,"origin":"","legend":"\u003cp\u003eConstructed Laboratory-scale LPG burner-based boiler\u003c/p\u003e","description":"","filename":"9.png","url":"https://assets-eu.researchsquare.com/files/rs-4643106/v1/beb386d11ae6c5e8c9e4f984.png"},{"id":61645613,"identity":"10a6475f-90ab-46e9-9979-abdefc54f1c4","added_by":"auto","created_at":"2024-08-02 11:04:12","extension":"png","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":355196,"visible":true,"origin":"","legend":"\u003cp\u003eWater tank with expansion tank, pressure gauge, relief valve and Thermocouples\u003c/p\u003e","description":"","filename":"10.png","url":"https://assets-eu.researchsquare.com/files/rs-4643106/v1/8670bacf272d9abf99cbe4ab.png"},{"id":61645604,"identity":"ab56392a-91e7-40b9-a2cc-f52b03caeb9f","added_by":"auto","created_at":"2024-08-02 11:04:12","extension":"png","order_by":11,"title":"Figure 11","display":"","copyAsset":false,"role":"figure","size":118653,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eFigure 9:\u003c/strong\u003e Measurement of the Temperature Profile without and with the HHO gas\u003c/p\u003e","description":"","filename":"11.png","url":"https://assets-eu.researchsquare.com/files/rs-4643106/v1/9c5da24f8d2d8997bd68848e.png"},{"id":61645607,"identity":"6c82bdf4-edc3-4e83-8768-e72d7eb32dfd","added_by":"auto","created_at":"2024-08-02 11:04:12","extension":"png","order_by":12,"title":"Figure 12","display":"","copyAsset":false,"role":"figure","size":131921,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eFigure 10: \u003c/strong\u003eDynamic Temperature and total Thermal Input of Fuel, for the measurement of the %Efficiency of the Boiler System without and with the HHO gas\u003c/p\u003e","description":"","filename":"12.png","url":"https://assets-eu.researchsquare.com/files/rs-4643106/v1/134cbe96ab716369270b31d9.png"},{"id":61645612,"identity":"d9120f53-c524-437f-b226-becdaf629b10","added_by":"auto","created_at":"2024-08-02 11:04:12","extension":"png","order_by":13,"title":"Figure 13","display":"","copyAsset":false,"role":"figure","size":24722,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eFigure 11:\u003c/strong\u003e Unburned Hydrocarbons (UC) Exhaust gas analysis\u003c/p\u003e","description":"","filename":"13.png","url":"https://assets-eu.researchsquare.com/files/rs-4643106/v1/8d7d8e63a9cac478ec1eafd3.png"},{"id":61645608,"identity":"59d020dc-51fa-467b-9f98-f5db923c112e","added_by":"auto","created_at":"2024-08-02 11:04:12","extension":"png","order_by":14,"title":"Figure 14","display":"","copyAsset":false,"role":"figure","size":23672,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eFigure 12:\u003c/strong\u003e Carbon Monoxide (CO) Exhaust gas analysis\u003c/p\u003e","description":"","filename":"14.png","url":"https://assets-eu.researchsquare.com/files/rs-4643106/v1/dfd3c00f4884e23511c63306.png"},{"id":64024095,"identity":"37ac4f9e-00e5-4bc0-ad84-801028b13aab","added_by":"auto","created_at":"2024-09-05 07:19:09","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":4286418,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4643106/v1/b3a9afa4-53e8-44ca-a5d3-03d1ae08de18.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Hydrogen-Enhanced Efficiency of LPG Central Heating Boilers","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eThe need for sustainable energy solutions in industrial processes has led to research into new methods to improve efficiency while reducing environmental impact. According to J.M. Babu et al [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e] and Ruggero Maria Santilli [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e] one promising method is the use of HHO gas, a stoichiometric mixture of hydrogen and oxygen produced through electrolysis, in combustion systems as study by Balaji Subramanian et al. [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. This study aims to explore how adding HHO gas to gas burners can make them more efficient and reduce emissions as shown by Tamer Nabil et al. [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. The idea is that by introducing HHO gas into an LPG stream, one can improve burner efficiency (Ammar A. Al-Rousan [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]), leading to a more complete LPG combustion while emitting fewer pollutants. To test this idea, a systematic research plan was developed, including setting-up experiments, collecting data and analyzing the results.\u003c/p\u003e \u003cp\u003eDuring the experiments, precise control over the flow of HHO gas into the combustion process was achieved using an ON/OFF switch and safety devices (back-flash arrestors). This allowed for precise adjustments to ensure safety and consistency. Initially, the gas burner was operated on pure LPG to establish its baseline performance, followed by abrupt addition of HHO gas to observe its effects on combustion according to M. Aravindan et al. [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Additionally, variations in HHO gas flow rates were explored to find the best operating parameters.\u003c/p\u003e \u003cp\u003eA crucial part of this research methodology was collecting data regularly, including temperature measurements, fuel flow rates, and HHO gas consumption (Arul Murugan et al. [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]). This data forms the basis for quantitative analysis, helping to identify trends and correlations indicative of the impact of HHO gas addition on burner efficiency. Advanced tools such as infrared cameras and gas analyzers are used to study flame characteristics and emissions profiles in detail.\u003c/p\u003e \u003cp\u003eIn summary, the present study proposes a new approach to improve gas burner efficiency through the strategic use of HHO gas. By understanding the mechanisms behind this enhancement, the study aimed to contribute to the advancement of sustainable combustion technologies and emphasize the importance of environmental stewardship in industrial processes as mentioned by Sa\u0026rsquo;ed A. Musmar et. Al. [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e].\u003c/p\u003e"},{"header":"2. Design, Construction and Operation of an Open-Side/End SS Tube","content":"\u003cp\u003eThe experimental setup aimed to analyze the combustion characteristics of both Liquefied Petroleum Gas (LPG) and Hydrogen-Enriched LPG (HHO) systems, with a focus on understanding their performance efficiency and emissions profiles (Usman et al [9)]. Central to this setup is the use of an LPG tank as the main fuel source, providing a stable fuel base for combustion experiments. Coupled with a commercial LPG burner equipped with adjustable flame control capabilities, this setup allows for precise regulation of LPG flow and flame intensity, ensuring controlled combustion conditions necessary for accurate experimentation (Adam J. Gee et al. [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]). Two HHO generators were also included in the setup, introducing a mixture of hydrogen and oxygen into the system. This addition presents a new element, offering the opportunity to investigate the combustion dynamics and efficiency of this HHO additive hydrogen technology (Zhe Zhao et al. [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]).\u003c/p\u003e \u003cp\u003eIn order to comprehensively assess the performance and characteristics of LPG and HHO combustion systems, a multifaceted monitoring approach has been carefully designed. Key to this approach were strategically placed gas flow meters, which accurately measure the flow rates of both LPG and HHO. These devices provide valuable data regarding the mass/volume of gases entering the combustion chamber, allowing for a deeper understanding of the combustion process. Additionally, an array of thermocouples has been strategically positioned throughout the system to monitor flame temperatures. By capturing temperature profiles at critical points, this setup enables one to gain insights into the thermal dynamics during the entire combustion cycle and access combustion efficiencies. Furthermore, a gas analyzer has been integrated into the system in order to obtain exhaust gas emissions. This sophisticated instrument examines combustion by-products, ensuring a comprehensive evaluation of combustion performance. Gas emissions such as CO and UH were measured to understand the environmental impact of both LPG and HHO combustion (Gregory Sherman et al. [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]). Together, this integrated monitoring system enables one to conduct a thorough analysis to optimize combustion processes and contribute to a more efficient and environmentally conscious utilization of LPG and HHO.\u003c/p\u003e \u003cp\u003eDuring the experiments, safety precautions were put in place to protect both personnel and equipment. This involved ensuring there were fire extinguishing equipment readily available to deal with any unexpected fires. The experiments were conducted in a controlled environment equipped with proper ventilation systems to reduce the risk of gas build-up and manage potential by-products effectively.\u003c/p\u003e \u003cp\u003eIn the initial stages of the study, focus was on establishing the infrastructure necessary to perform the experiments precisely and safely. This involved the design and construction of an open-side/end stainless-steel tube fitted with an LPG burner, which served as the cornerstone of the investigation (as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The tube, measuring 2 meters in length, 17 centimeters in diameter, and 3 mm thickness, was crafted with precision to ensure both durability and resistance to corrosion, vital for the extended duration of the study. Key to this setup was the integration of the Baltur BTG-3 LPG burner, renowned for its adaptability and efficient utilization of LPG at 30 mbar pressure, with a power range spanning from 16.6 to 42.7 kW. To facilitate accurate temperature monitoring, high-temperature J-type thermocouples were strategically placed at intervals of 20\u0026ndash;25 cm along the tube. Additionally, to ensure comprehensive data collection, a gas flow meter, a precision mass balance and a Pico DAQ system were used.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1 Temperature Profiles along the open-side/end SS tube\u003c/h2\u003e \u003cp\u003eThe impact of introducing HHO gas on the performance of an open-side/end stainless steel tube equipped with an LPG burner (see Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e) was investigated, aiming to gather qualitative insights into combustion. This analysis focused on several key parameters to observe any noticeable changes. Initially, the flame color was closely observed, specifically looking for any transition from its typical yellowish color to blueish upon the introduction of HHO gas. Furthermore, the flame temperature was recorded, comparing readings between scenarios without and with HHO gas to identify any differences. Additionally, examination extended to the preliminary assessment of emissions, particularly the levels of Unburned Hydrocarbons (UH) and Carbon Monoxide (CO) in the exhaust gases. These findings contribute to a deeper understanding of the potential effects of HHO gas supplementation on combustion processes, offering valuable insights for further research and application in various industrial applications.\u003c/p\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e shows the thermal images of the flames without (left image) and with the introduction of HHO gas into LPG burners (right image). HHO gas, a blend of hydrogen and oxygen, offers distinct advantage due to its higher flame speed. This promotes improved combustion characteristics and higher heat-generated compared to using LPG alone. By introducing HHO gas alongside LPG, the combustion process becomes more efficient, leading to better utilization of fuel and more heat generated. This synergy between HHO gas and LPG shows a potential for enhancing the performance of burners across various applications, highlighting its potential to contribute to cleaner and more effective combustion processes.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eFurthermore, Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e shows the Temperature profiles inside the SS tube without HHO gas and after the introduction of the HHO gas. Due to higher efficiency, more heat is generated and the corresponding temperatures are higher in the case of the introduction of the HHO gas.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2 Qualitative Flame Observation in an Open-side/end tube\u003c/h2\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e shows the quality of the flame without and with the HHO gas. The pure LPG flame appears yellowish blur, suggesting an incomplete combustion reaction. In contrast, with HHO gas, the LPG\u0026thinsp;+\u0026thinsp;HHO flame becomes blueish-clean, indicative of complete combustion. This scenario also exhibits higher temperatures along the SS tube in comparison to using LPG alone as shown previously in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e. Additionally, in the case of HHO gas, the flame appears shorter due to its enhanced flame velocity completing the combustion process faster, thus shortening the flame-combustion length. These observations underscore the role of HHO in promoting cleaner combustion and elevating thermal dynamics within the SS tube setup. At the same time, preliminary exhaust gas emissions\u0026rsquo; analyses indicated much less Unburned Hydrocarbons (UH) and Carbon Monoxides (CO), something that was further investigated qualitatively during the experiments on the boiler.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"3. Design, Construction and Operation of HHO Generators and a Laboratory-scale LPG burner-based boiler","content":"\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003e3.1 Design and Construction of HHO Generators\u003c/h2\u003e \u003cp\u003eTwo HHO Generators were designed, constructed and operated. The first (\u003cb\u003eHHO1\u003c/b\u003e) (shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e and Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e) was designed based on a 90DCV Power Supply with a maximum current output of 16.6 Amperes (total of 1500Watt power). The second one (\u003cb\u003eHHO2\u003c/b\u003e) (shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e and Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e) was designed based on a 28.7DCV Power Supply with a maximum current output of 52 Amperes (total of 1500Watt power) [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe electrolytic cells designed for HHO generation integrate various components to allow controlled gas production. Stainless steel electrodes are used and submerged in a solution of deionized water and electrolyte, usually potassium hydroxide (KOH). Before experimentation, the electrolyte concentration is adjusted to achieve the desired HHO gas output while reducing energy consumption. A variable DC power supply provides the necessary voltage and current, starting electrolysis and breaking down water into stoichiometric hydrogen and oxygen gases. The resulting HHO gas flows through two water-bubblers to remove impurities and ensure purity. The HHO gas is instantly pre-mixed with LPG in the pre-mixing chamber of the burner. The gas pre-mixing system includes flow control valves, allowing precise regulation of both LPG and HHO for optimal instant blending before combustion. The mixing ratio of HHO and LPG can be adjusted according to specific requirements and application needs. This comprehensive setup allows for the customization and controlled deployment of such HHO mixtures, providing efficient and versatile energy solutions for existing conventional industrial/residential gas-boilers.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003e3.2 Design and Construction of a Laboratory-scale LPG burner-based boiler\u003c/h2\u003e \u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003eThe laboratory-scale LPG burner-based boiler (shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig11\" class=\"InternalRef\"\u003e9\u003c/span\u003e) design underscores safety, efficiency, and performance for experimental pursuits, particularly in capturing dynamic heating capacity. Detailed attention was devoted to construction, employing a robust insulated copper water tank to ensure both pressure resilience and heat retention, complemented by the reliable Baltur BTG 3 LPG burner kit for enduring performance. The burner was connected to the boiler which was interconnected to the water tank through insulated copper pipes for secure and efficient connections. A water-pump was used to directly circulate the boiler\u0026rsquo;s water into the water tank. Safety remains paramount, with multiple features incorporated to safeguard against potential hazards, including pressure relief valves, expansion tanks, thermocouples for temperature monitoring, and emergency shut-off mechanisms. The control system was equipped with precision pressure and temperature gauges (shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig12\" class=\"InternalRef\"\u003e10\u003c/span\u003e) to ensure a safe and seamless operation. Experimental procedures encompass a comprehensive examination of parameters such as heating capacity and exhaust gas emissions (CO and UH), with a specific focus on evaluating system\u0026rsquo;s thermal efficiency and the environmental impact of HHO gas additions.\u003c/p\u003e \u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003e3.3 Results and Discussion on a Laboratory-scale LPG burner-based boiler\u003c/h2\u003e \u003cp\u003eThe Boiler/LPG burner was initially operated with LPG alone recording the Inlet and Outlet water Temperature and the total instant Thermal Input of LPG fuel as a function of time, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig11\" class=\"InternalRef\"\u003e9\u003c/span\u003e. The water Temperatures were recorder using the J-type thermocouples installed in the Inlet and Outlet of the water tank. The total instant Thermal Input of LPG fuel was calculated by recording the total instant mass of the LPG consumed and the Lower Calorific Value (46.1312MJ/kg LPG) of the LPG having a molecular composition of 70%Propane and 30% Butane.\u003c/p\u003e \u003cp\u003eThe efficiency of the boiler running on LPG is proportional to the Temperature gradient (dT/dt\u0026thinsp;=\u0026thinsp;0.02363) of the Inlet water tank temperature profile and inverse proportional to the total instant Thermal Input gradient of LPG (dH/dt\u0026thinsp;=\u0026thinsp;0.01551), as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig12\" class=\"InternalRef\"\u003e10\u003c/span\u003e. Therefore, the efficiency of the boiler running on LPG is proportional to 0.02363/0.01551\u0026thinsp;=\u0026thinsp;1.5235.\u003c/p\u003e \u003cp\u003eConsequently, the Boiler/LPG burner was operated with LPG and the introduction of HHO gas continuing recording the Inlet and Outlet water Temperature and the total instant Thermal Input of LPG fuel as a function of time, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig11\" class=\"InternalRef\"\u003e9\u003c/span\u003e. The water Temperatures and total instant Thermal Input of (LPG\u0026thinsp;+\u0026thinsp;HHO) fuel were also calculated similarly. The contribution of HHO gas in the total instant Thermal Input was calculated by recording the total instant mass of the H\u003csub\u003e2\u003c/sub\u003e in the HHO mixture consumed and the Lower Calorific Value of 119.94MJ/kg of H\u003csub\u003e2\u003c/sub\u003e.\u003c/p\u003e \u003cp\u003eThe efficiency of the boiler running on LPG\u0026thinsp;+\u0026thinsp;HHO is proportional to the Temperature gradient (dT/dt\u0026thinsp;=\u0026thinsp;0.02987) of the Inlet water tank temperature profile and inverse proportional to the total instant Thermal Input gradient of LPG\u0026thinsp;+\u0026thinsp;HHO (dH/dt\u0026thinsp;=\u0026thinsp;0.01779), as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig12\" class=\"InternalRef\"\u003e10\u003c/span\u003e. Therefore, the efficiency of the boiler running on LPG is proportional to 0.02987/0.01779\u0026thinsp;=\u0026thinsp;1.6790.\u003c/p\u003e \u003cp\u003eThe ratio of the efficiencies with HHO and to without HHO gas is calculated to be 1.6790/1.5235\u0026thinsp;=\u0026thinsp;1.102. In other words, the introduction of HHO gas in the LPG increases the thermal efficiency of the boiler by about 10%.\u003c/p\u003e \u003cp\u003eAdditionally, the reduction of exhaust gas emissions, particularly Unburned Hydrocarbons (UH) and Carbon Monoxide (CO), were quantitatively measured without and with the introduction of HHO gas into the combustion process by using gas analyzers, at the end of each mode of operation (LPG or LPG\u0026thinsp;+\u0026thinsp;HHO), as indicated in Fig.\u0026nbsp;\u003cspan refid=\"Fig11\" class=\"InternalRef\"\u003e9\u003c/span\u003e.\u003c/p\u003e \u003cp\u003eThe results revealed a remarkable reduction in gas-emissions with the introduction of HHO gas. Specifically, there was an 81% decrease in unburned hydrocarbons (UH) and a 53% decrease in carbon monoxide (CO), as shown in Figs.\u0026nbsp;\u003cspan refid=\"Fig13\" class=\"InternalRef\"\u003e11\u003c/span\u003e\u0026ndash;\u003cspan refid=\"Fig14\" class=\"InternalRef\"\u003e12\u003c/span\u003e, correspondingly. These findings underscore the effectiveness of HHO gas in enhancing combustion efficiency and mitigating harmful emissions, highlighting its potential role in promoting environmental sustainability and air quality improvements.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"4. Conclusions","content":"\u003cp\u003eThrough a systematic study, the introduction of HHO gas into an LPG burner/boiler showed a notable 10% increase in thermal efficiency. In addition, integrating HHO gas led to substantial reductions in exhaust gas emissions, with an impressive 81% decrease in unburned hydrocarbons (UH) and a 53% reduction in Carbon Monoxide (CO) in agreement with Mohamed M. et al. [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e], N. Yuca et. al. [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e] and Shuofeng Wang et al. [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e] who reported similar improvements in emission\u0026rsquo;s reductions.\u003c/p\u003e \u003cp\u003eThe results of the use of such HHO technologies are very promising for enhancing efficiencies in sustainable combustion technologies and for promoting environmental stewardship not only for Boilers but potentially for gas-turbines and Ships/Heavy Trucks/Generators\u0026rsquo; Internal Combustion Engines (ICE) in industrial applications as well as road [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e] and maritime transportation. Similar results were obtained by Ch. Christodoulou [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e] for HHO application on Buses and Vans where fuel savings of 5\u0026ndash;25% and exhaust gas emissions\u0026rsquo; reductions of more than 20% were achieved.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eDear Editor-in-Chief,All authors whose names appear on the submission,1. made substantial contributions to the conception or design of the work; or the acquisition, analysis, or interpretation of data; or the creation of new software used in the work;2. drafted the work or revised it critically for important intellectual content;3. approved the version to be published; and4. agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eDear Editor-in-Chief,The full set of data that support the findings of this study are available from the corresponding author, George N Karagiorgis ([email protected]), upon reasonable request. The data are not publicly available due to restrictions in, confidentiality. Interested researchers can contact the corresponding author to request access to the data.Furthermore, please note that the final results of this study, are properly presented as figures in the paper.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eJ.M. Babu, K. Sunil Kumar, R. Ramesh Kumar, \u0026Uuml;mit Ağbulut, Abdul Razak, Deepak Thakur, Vikram Sundara, Mohammad Asif, \u0026ldquo;Production of HHO gas in the water-electrolysis unit and the influences of its introduction to CI engine along with diesel-biodiesel blends at varying injection pressures\u0026rdquo;, International Journal of Hydrogen Energy, Vol. 52, Part D (2024) 865-885 \u003c/li\u003e\n\u003cli\u003eRuggero Maria Santilli, \u0026ldquo;A new gaseous and combustible form of water\u0026rdquo;, International Journal of Hydrogen Energy, Vol. 31, Issue 9, (2006) 1113-1128\u003c/li\u003e\n\u003cli\u003eBalaji Subramanian, Saleel Ismail, \u0026ldquo;Production, and use of HHO gas in IC engines\u0026rdquo;, International Journal of Hydrogen Energy, Vol. 43, Issue 14 (2018) 7140-7154\u003c/li\u003e\n\u003cli\u003eTamer Nabil, Mohamed M. Khairat Dawood, \u0026ldquo;Enabling efficient use of oxy-hydrogen gas (HHO) in selected engineering applications; transportation and sustainable power generation\u0026rdquo;, Journal of Cleaner Production, Vol. 237 (2019) 117798\u003c/li\u003e\n\u003cli\u003eAmmar A. Al-Rousan, \u0026ldquo;Reduction of fuel consumption in gasoline engines by introducing HHO gas into intake manifold\u0026rdquo;, International Journal of Hydrogen Energy, Vol.35, Issue 23 (2010) 12930-12935\u003c/li\u003e\n\u003cli\u003eM. Aravindan, K. Madhesh, G. Praveen Kumar, Madhan K. Arulanandam, Srinath Murali, Neelam Sheoran, Nirmal Waykole, Rajmohan Muthaiah, Pawan Sharma, Asheesh Anand, \u0026ldquo;Computational and Chemical Kinetics Analysis of Hydrogen-Blended LPG for Domestic Cook Stove Burners\u0026rdquo;, Energy Conversion and Management, Vol.22 (2024) 100568\u003c/li\u003e\n\u003cli\u003eArul Murugan, Marc de Huu, Thomas Bacquart, Janneke van Wijk, Karine Arrhenius, Indra te Ronde, David Hemfrey, \u0026ldquo;Measurement challenges for hydrogen vehicles\u0026rdquo;, International Journal of Hydrogen Energy, Vol.44, Issue 35 (2019) 19326-19333\u003c/li\u003e\n\u003cli\u003eSa\u0026rsquo;ed A. Musmar, Ammar A. Al-Rousan, \u0026ldquo;Effect of HHO gas on combustion emissions in gasoline engines\u0026rdquo;, Fuel, Vol.90, Issue10 (2011) 3066-3070\u003c/li\u003e\n\u003cli\u003eMuhammad \u0026amp; Naqvi, Muhammad \u0026amp; Saleem, Muhammad Wajid \u0026amp; Hussain, Jafar \u0026amp; Raza Naqvi, Salman \u0026amp; Jahangir, Shahzaib \u0026amp; Usama, Muhammad \u0026amp; Idrees, Saad \u0026amp; Anukam, Anthony, \u0026ldquo;Use of Gasoline, LPG and LPG-HHO Blend in SI Engine\u0026rdquo;, Special Issue: Progress in Energy Conversion Systems and Emission Control, Processes, 8(1), 74 (2020) 1-15\u003c/li\u003e\n\u003cli\u003eAdam J. Gee, Douglas B. Proud, Neil Smith, Alfonso Chinnici, Paul R. 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Dalkılı\u0026ccedil;, \u0026ldquo;Effect of hydrogen and oxygen addition as a mixture on emissions and performance characteristics of a gasoline engine\u0026rdquo;, International, Journal of Hydrogen Energy, Vol. 40, Issue 28 (2015) 8750-8760\u003c/li\u003e\n\u003cli\u003eShuofeng Wang, Changwei Ji, Bo Zhang, Xiaolong Liu, \u0026ldquo;Performance of a hydroxygen-blended gasoline engine at different hydrogen volume fractions in the hydroxygen\u0026rdquo;, International Journal of Hydrogen Energy, Vol. 37, Issue 17 (2012)13209-13218\u003c/li\u003e\n\u003cli\u003e\u0026ldquo;Integration of innovative green technologies on existing public transportation buses for 5% to 30% fuel saving\u0026rdquo; BUS-FUEL-SAVING, INTEGRATED/0916/0031,2019-2022\u003c/li\u003e\n\u003cli\u003eChristina Ch. Christodoulou, \u0026ldquo;Fuel Savings and Reduction of Exhaust Gas Emissions by Application of HHO Technologies on Existing Internal Combustion Engine (ICE) Vehicles\u0026rdquo; 7th Int. Conf. on RES \u0026amp; Energy Efficiency, Nicosia, Oct 12-14, 2023\u003c/li\u003e\n\u003cli\u003eChristina Ch. Christodoulou, \u0026ldquo;Fuel Savings and Reduction of Exhaust Gas Emissions by Application of HHO Technologies on Existing Internal Combustion Engine (ICE) Vehicles\u0026rdquo;, 3rd Doctoral Colloquium of the Cyprus Rectors\u0026rsquo; Conference, Nicosia, April 13, 2024\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Hydrogen technologies, HHO gas, fuel savings, boiler efficiency, reduction of exhaust gas emissions","lastPublishedDoi":"10.21203/rs.3.rs-4643106/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4643106/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThe search for sustainable energy solutions has led to new approaches in various industrial sectors, including combustion systems. The present study represents a detailed investigation for the potential improvement of an LPG burner/Boiler efficiency by adding a stoichiometric mixture of hydrogen and oxygen (HHO gas) in the main fuel. The study included observation of the quality of the flame and its temperature profile without and with the introduction of HHO gas in an open-side/end combustion tube. It also included the construction of a laboratory scale LPG Burner/Boiler with a water tank and its operation without and with the introduction of the HHO gas in the LPG burner. Diagrams of water temperature and theoretical heat input as a function of time were used to compare the Boilers efficiency without and with the introduction of the HHO in the LPG burner. The study proved that adding HHO gas to the combustion process can significantly enhance fuel efficiency at least by 10% while reducing exhaust gas emissions by \u0026gt;\u0026thinsp;80% the Unburned Hydrocarbons (UH) and by \u0026gt;\u0026thinsp;50% the Carbon Monoxides (CO). The results of the use of such hydrogen technologies are very promising for enhancing efficiencies in sustainable combustion technologies and for promoting environmental stewardship not only for Boilers but potentially for gas-turbines and Ships/Heavy Trucks/Generators Internal Combustion Engines (ICE) in industrial applications as well as road and maritime transportation.\u003c/p\u003e","manuscriptTitle":"Hydrogen-Enhanced Efficiency of LPG Central Heating Boilers","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-08-02 11:04:07","doi":"10.21203/rs.3.rs-4643106/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"77beed59-d5f9-47d8-a414-8e3ca1b1105c","owner":[],"postedDate":"August 2nd, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2024-09-14T09:32:49+00:00","versionOfRecord":[],"versionCreatedAt":"2024-08-02 11:04:07","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-4643106","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4643106","identity":"rs-4643106","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}