Pub Date : 2023-12-01DOI: 10.1016/j.enbenv.2023.11.011
Yazhou Tang, Dapeng Jin, Zhiying Wang, Fengxu Han
In recent 20 years, the rapidly development of thermoelectric materials promotes thermoelectric s application in large scale cooling area, i.e. air-conditioner. To provide quiet working environment for the driver of high-speed railway, a kilowatt scale air-conditioner was designed. Firstly, a novel thermoelectric cooler with maximum cooling capacity of 450 W was designed with 199 thermoelectric elements, and the cooling performance were investigated under different cold and hot side heat exchange capacity. Second, the hot and cold side heat exchangers were optimized adopting genetic algorithm. Finally, a high coefficient of performance (COP) thermoelectric air conditioning (TEAC) system was designed for high-speed railway locomotive. The TEAC system comprising 16 TECs achieved a cooling capacity of 2342 W with a COP of 0.5 in cooling mode, and meets one 1HP TEAC requirements. The temperature field inside the locomotive was uniform and exhibited a linear correlation with the supplied air temperature. This research demonstrates the utility of high-power TEAC in high-speed railway carriages, providing valuable insights for the application of TEAC technology.
{"title":"The extreme high cooling capacity thermoelectric cooler optimal design for kilowatts scale thermoelectric air-conditioner of high-speed railway carriage","authors":"Yazhou Tang, Dapeng Jin, Zhiying Wang, Fengxu Han","doi":"10.1016/j.enbenv.2023.11.011","DOIUrl":"10.1016/j.enbenv.2023.11.011","url":null,"abstract":"<div><div>In recent 20 years, the rapidly development of thermoelectric materials promotes thermoelectric s application in large scale cooling area, i.e. air-conditioner. To provide quiet working environment for the driver of high-speed railway, a kilowatt scale air-conditioner was designed. Firstly, a novel thermoelectric cooler with maximum cooling capacity of 450 W was designed with 199 thermoelectric elements, and the cooling performance were investigated under different cold and hot side heat exchange capacity. Second, the hot and cold side heat exchangers were optimized adopting genetic algorithm. Finally, a high coefficient of performance (COP) thermoelectric air conditioning (TEAC) system was designed for high-speed railway locomotive. The TEAC system comprising 16 TECs achieved a cooling capacity of 2342 W with a COP of 0.5 in cooling mode, and meets one 1HP TEAC requirements. The temperature field inside the locomotive was uniform and exhibited a linear correlation with the supplied air temperature. This research demonstrates the utility of high-power TEAC in high-speed railway carriages, providing valuable insights for the application of TEAC technology.</div></div>","PeriodicalId":33659,"journal":{"name":"Energy and Built Environment","volume":"6 2","pages":"Pages 378-386"},"PeriodicalIF":0.0,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138622495","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-01DOI: 10.1016/j.enbenv.2023.11.010
Yanjun Li , Weixue Jiang , Jinwei Song , Zuo Xu , Xinyu Tang , Shuhong Li , Kai Du
This paper constructed a mathematical model of ammonia-water nanofluid falling film generation outside the vertical tube, which considers the change of the film thickness of the falling film solution, the thermal convection along the film thickness direction and the physical properties of the solution. By solving the mathematical model, the temperature field and other elements of the liquid film were determined. The influence of the properties of the working fluid on the heat and mass transfer in the falling film process is investigated. According to the calculation results, a method of adding nanoparticles in the process of ammonia falling film generation is proposed. The simulation results showed that the heat efficiency of entire falling film process can be enhanced by adding an appropriate amount of Al2O3 nanoparticles. When the added Al2O3 nanoparticles are 1 vol.%, the coefficient of the heat transfer is increased by about 4%, and the mass transfer effect is also improved by about 12%. In brief, the establishment of this model aims to improve heat and mass transfer efficiency and promote the application and integration of low-grade waste heat or renewable energy technologies in built environment.
{"title":"Numerical investigation of falling film generation outside vertical tube with ammonia-water nanofluid","authors":"Yanjun Li , Weixue Jiang , Jinwei Song , Zuo Xu , Xinyu Tang , Shuhong Li , Kai Du","doi":"10.1016/j.enbenv.2023.11.010","DOIUrl":"10.1016/j.enbenv.2023.11.010","url":null,"abstract":"<div><div>This paper constructed a mathematical model of ammonia-water nanofluid falling film generation outside the vertical tube, which considers the change of the film thickness of the falling film solution, the thermal convection along the film thickness direction and the physical properties of the solution. By solving the mathematical model, the temperature field and other elements of the liquid film were determined. The influence of the properties of the working fluid on the heat and mass transfer in the falling film process is investigated. According to the calculation results, a method of adding nanoparticles in the process of ammonia falling film generation is proposed. The simulation results showed that the heat efficiency of entire falling film process can be enhanced by adding an appropriate amount of Al<sub>2</sub>O<sub>3</sub> nanoparticles<sub>.</sub> When the added Al<sub>2</sub>O<sub>3</sub> nanoparticles are 1 vol.%, the coefficient of the heat transfer is increased by about 4%, and the mass transfer effect is also improved by about 12%. In brief, the establishment of this model aims to improve heat and mass transfer efficiency and promote the application and integration of low-grade waste heat or renewable energy technologies in built environment.</div></div>","PeriodicalId":33659,"journal":{"name":"Energy and Built Environment","volume":"6 2","pages":"Pages 362-377"},"PeriodicalIF":0.0,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138617164","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-25DOI: 10.1016/j.enbenv.2023.11.008
Rolains Golchimard Elenga , Li Zhu , Steivan Defilla
The need to improve building envelope components and reduce energy consumption is becoming increasingly crucial. The use of phase-change material (PCM) technologies is a viable solution to reduce energy consumption in buildings and associated greenhouse gas emissions. However, the performance of PCMs in buildings is strongly dependent on the melting temperatures and the climate conditions of the building's location. Therefore, the present study presents an optimisation-based approach to assessing the performance of building walls integrated with PCMs at different melting temperatures. To achieve this goal, a multiobjective genetic algorithm is used in conjunction with EnergyPlus building energy models to determine the optimal balance between total building energy consumption, lifecycle cost, and CO2 emissions. The proposed approach is applied to a single-family residential building located in six locations in the Central African sub-region classified as tropical savanna climate (Aw), hot semi-arid climate (Bsh), tropical rainforest climate (Af), and tropical monsoon climate (Am). Two different PCM technologies (InfiniteRPCM and BiocPCM) are applied to four wall types (brick, concrete block, cast concrete, and earth), and their parametric models are developed in EnergyPlus to optimise the melting temperature, thickness, and location of each PCM layer simultaneously. An optimisation is conducted for each selected wall and each location, and the optimised buildings are systematically compared to the reference buildings. The optimisation results showed that regardless of the climate zone and wall type, the application of PCMs with different melting temperatures significantly reduced energy consumption and CO2 emissions. Moreover, the results showed a different set of optimal solutions for each climate zone and wall type. The optimal solutions reduced the total energy, life cycle cost, and CO2 emissions by up to 47.80 %, 29.62 %, and 52.96 %, respectively.
{"title":"Performance evaluation of different building envelopes integrated with phase change materials in tropical climates","authors":"Rolains Golchimard Elenga , Li Zhu , Steivan Defilla","doi":"10.1016/j.enbenv.2023.11.008","DOIUrl":"10.1016/j.enbenv.2023.11.008","url":null,"abstract":"<div><div>The need to improve building envelope components and reduce energy consumption is becoming increasingly crucial. The use of phase-change material (PCM) technologies is a viable solution to reduce energy consumption in buildings and associated greenhouse gas emissions. However, the performance of PCMs in buildings is strongly dependent on the melting temperatures and the climate conditions of the building's location. Therefore, the present study presents an optimisation-based approach to assessing the performance of building walls integrated with PCMs at different melting temperatures. To achieve this goal, a multiobjective genetic algorithm is used in conjunction with EnergyPlus building energy models to determine the optimal balance between total building energy consumption, lifecycle cost, and CO2 emissions. The proposed approach is applied to a single-family residential building located in six locations in the Central African sub-region classified as tropical savanna climate (Aw), hot semi-arid climate (Bsh), tropical rainforest climate (Af), and tropical monsoon climate (Am). Two different PCM technologies (InfiniteRPCM and BiocPCM) are applied to four wall types (brick, concrete block, cast concrete, and earth), and their parametric models are developed in EnergyPlus to optimise the melting temperature, thickness, and location of each PCM layer simultaneously. An optimisation is conducted for each selected wall and each location, and the optimised buildings are systematically compared to the reference buildings. The optimisation results showed that regardless of the climate zone and wall type, the application of PCMs with different melting temperatures significantly reduced energy consumption and CO2 emissions. Moreover, the results showed a different set of optimal solutions for each climate zone and wall type. The optimal solutions reduced the total energy, life cycle cost, and CO2 emissions by up to 47.80 %, 29.62 %, and 52.96 %, respectively.</div></div>","PeriodicalId":33659,"journal":{"name":"Energy and Built Environment","volume":"6 2","pages":"Pages 332-346"},"PeriodicalIF":0.0,"publicationDate":"2023-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139298847","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-25DOI: 10.1016/j.enbenv.2023.11.007
Rui Li , Jinping Li , Junjie Zhu , Xuemin Zhang , Xiao Guo , Vojislav Novakovic
The photovoltaic/thermal (PV/T) system, as an energy conversion system to generate electricity and heat, has great application potential in northwest zone of ample solar energy resource in China. The working media inside the micro heat pipe (MHP) of previous studies was acetone. Compared to acetone, R141b has better stability and lower solubility. For working fluid as R141b in the MHP, higher Reynolds Number (Re) theoretically means better heat transfer. During the typical winter season, when the inclination of the PV panel was 45°, the average power conversion efficiency (PCE) and thermal conversion efficiency (TCE) can reach 12.8 and 26.4 %. Furthermore, in order to reduce the simulation time and facilitate the research, the study establishes the fitting equation of MHP-PV/T surface temperature based on solar radiation intensity and environmental temperature with an average error of 7.6 %. Furthermore, a three-dimensional mathematical model of MHP-PV/T system was developed and validated with experimental results, investigating the Re of R141b in the MHPs and calculating the related heat transfer coefficient (h) based on Re. The simulation showed that the Re and h at the condensation section of the MHP were bigger than those at the evaporation section. The Re and h increased with the water temperature decrease of airfoil heat exchanger and solar radiation intensity rise. Lastly, when water temperature of airfoil heat exchanger was unchanged, the impact of solar radiation intensity on h was greater than Re. When the solar radiation intensity remained unchanged and the water temperature decreased, Re was the main reason for affecting the change of h. The research results will give a scientific foundation and technical application for the MHP-PV/T, as well as more efficient solar energy applications in the future.
{"title":"Experimental studies on the heat transfer performance of MHP-PV/T enhanced by Reynolds number","authors":"Rui Li , Jinping Li , Junjie Zhu , Xuemin Zhang , Xiao Guo , Vojislav Novakovic","doi":"10.1016/j.enbenv.2023.11.007","DOIUrl":"10.1016/j.enbenv.2023.11.007","url":null,"abstract":"<div><div>The photovoltaic/thermal (PV/T) system, as an energy conversion system to generate electricity and heat, has great application potential in northwest zone of ample solar energy resource in China. The working media inside the micro heat pipe (MHP) of previous studies was acetone. Compared to acetone, R141b has better stability and lower solubility. For working fluid as R141b in the MHP, higher Reynolds Number (<em>Re</em>) theoretically means better heat transfer. During the typical winter season, when the inclination of the PV panel was 45°, the average power conversion efficiency (<em>PCE</em>) and thermal conversion efficiency (<em>TCE</em>) can reach 12.8 and 26.4 %. Furthermore, in order to reduce the simulation time and facilitate the research, the study establishes the fitting equation of MHP-PV/T surface temperature based on solar radiation intensity and environmental temperature with an average error of 7.6 %. Furthermore, a three-dimensional mathematical model of MHP-PV/T system was developed and validated with experimental results, investigating the <em>Re</em> of R141b in the MHPs and calculating the related heat transfer coefficient (<em>h</em>) based on <em>Re</em>. The simulation showed that the <em>Re</em> and <em>h</em> at the condensation section of the MHP were bigger than those at the evaporation section. The <em>Re</em> and <em>h</em> increased with the water temperature decrease of airfoil heat exchanger and solar radiation intensity rise. Lastly, when water temperature of airfoil heat exchanger was unchanged, the impact of solar radiation intensity on <em>h</em> was greater than <em>Re</em>. When the solar radiation intensity remained unchanged and the water temperature decreased, <em>Re</em> was the main reason for affecting the change of <em>h</em>. The research results will give a scientific foundation and technical application for the MHP-PV/T, as well as more efficient solar energy applications in the future.</div></div>","PeriodicalId":33659,"journal":{"name":"Energy and Built Environment","volume":"6 2","pages":"Pages 320-331"},"PeriodicalIF":0.0,"publicationDate":"2023-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139304401","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-23DOI: 10.1016/j.enbenv.2023.11.005
Yanni Liu , Ningning Wang , Yunfei Ding , Jiezhi Chen , Yilin You
Phase Change Materials (PCMs) are one of the most promising materials for storing thermal energy and supplying stored energy for Domestic Hot Water (DHW) applications. This paper presents a detailed numerical analysis to describe transient heat transfer in a phase-change composite thermal energy-storage system. The composite was composed of 92.5 % stearic acid, 7.5 % carbon fiber, and a heat transfer fluid (ethylene cellulose). Numerics were implemented using ‘The Integrated Computer Engineering and Manufacturing code for Computational Fluid Dynamics’. The results were validated using experimental data and demonstrated acceptable agreement and an accurate representation of this specific transient heat transfer problem. The difference between the simulation and experimental results was so small that we considered the simulation results reliable. When the phase change heat storage process is about 800 s, the heat is transferred to the entire phase change heat storage tank, and when the phase change heat storage process is about 10800s, the temperature of all composite phase change materials reaches the phase change temperature. When the phase change heat storage process is about 8 h, the temperature of the composite phase change material in the whole phase change heat storage tank reaches 90 ℃. The temperature tends to be stable after the phase transition heat release process for about 500 s, and there is no large fluctuation in temperature with the passage of time. When the phase change heat release process reaches 7200 s, the cold-water inlet temperature is 15 ℃, 20 ℃ and 25 ℃, and the outlet temperature is 25.8 ℃, 30.8 ℃ and 35.7 ℃, respectively, indicating that the application of composite phase change materials in phase change heat storage water tank has a good effect.
{"title":"Numerical simulation of the melting and solidification processes of stearic acid/carbon fiber composite phase change material for solar water heating applications","authors":"Yanni Liu , Ningning Wang , Yunfei Ding , Jiezhi Chen , Yilin You","doi":"10.1016/j.enbenv.2023.11.005","DOIUrl":"10.1016/j.enbenv.2023.11.005","url":null,"abstract":"<div><div>Phase Change Materials (PCMs) are one of the most promising materials for storing thermal energy and supplying stored energy for Domestic Hot Water (DHW) applications. This paper presents a detailed numerical analysis to describe transient heat transfer in a phase-change composite thermal energy-storage system. The composite was composed of 92.5 % stearic acid, 7.5 % carbon fiber, and a heat transfer fluid (ethylene cellulose). Numerics were implemented using ‘The Integrated Computer Engineering and Manufacturing code for Computational Fluid Dynamics’. The results were validated using experimental data and demonstrated acceptable agreement and an accurate representation of this specific transient heat transfer problem. The difference between the simulation and experimental results was so small that we considered the simulation results reliable. When the phase change heat storage process is about 800 s, the heat is transferred to the entire phase change heat storage tank, and when the phase change heat storage process is about 10800s, the temperature of all composite phase change materials reaches the phase change temperature. When the phase change heat storage process is about 8 h, the temperature of the composite phase change material in the whole phase change heat storage tank reaches 90 ℃. The temperature tends to be stable after the phase transition heat release process for about 500 s, and there is no large fluctuation in temperature with the passage of time. When the phase change heat release process reaches 7200 s, the cold-water inlet temperature is 15 ℃, 20 ℃ and 25 ℃, and the outlet temperature is 25.8 ℃, 30.8 ℃ and 35.7 ℃, respectively, indicating that the application of composite phase change materials in phase change heat storage water tank has a good effect.</div></div>","PeriodicalId":33659,"journal":{"name":"Energy and Built Environment","volume":"6 2","pages":"Pages 297-306"},"PeriodicalIF":0.0,"publicationDate":"2023-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139303017","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-17DOI: 10.1016/j.enbenv.2023.11.004
Panpan Zhai , Jinping Li , Tingzhou Lei , Junjie Zhu , Vojislav Novakovic
Passive solar house technology has been spread for many farmers and herdsmen to improve the indoor thermal environment in Tibetan. However, due to lackage of fuels and arid cold in winter, dry cow dung and coal are popularly fired in stove in passive solar houses, which leads to indoor air pollution and poor indoor comfort. For improving indoor thermal comfort of Tibetan, an active solar heating system which consists of 7 sets of tandem solar water heaters with 30 glass evacuated solar tubes, low temperature floor heating and circulation controller was developed and tested for a common house without insulation in Gan-nan Tibetan area. Its indoor environment was compared and evaluated by PMV-PPD and LPD method to that of the same passive solar house heated by coal stove. On sunny, cloudy and snow days, the active solar heating system provided 113.1, 46.4 and 26.3 kWh of heat to room. The indoor humidity and wind speed of the experimental building were better. The indoor temperatures were 17.2-20.7, 14.9-20.5 and 11.0-14.8°C, while the compared building were 8.9-14.8, 10.1-12.1 and 7.2-10.5°C. The maximum temperature difference between head and ankle were 1.7, 1.6 and 0.9℃, and the compared building were 4, 4 and 4.7℃. The PMV-PPD on sunny day were class I and II; on cloudy day were class I, II and III; on snow day was class III. On sunny and cloudy days, the LPD were class I, on snow day was class I, II and III. The PMV-PPD and LPD for typical days of the compared building were class III. During the 179 days, the mean indoor temperature exceeded 14 ℃ for 81 days, the solar active heating system provided 12471 kWh of heat to room. The CO2 emission reduction was 12905 kg. The system's dynamic payback period were 2.57 years.
{"title":"Indoor thermal comfort comparison between passive solar house with active solar heating and without active solar heating in Tibetan","authors":"Panpan Zhai , Jinping Li , Tingzhou Lei , Junjie Zhu , Vojislav Novakovic","doi":"10.1016/j.enbenv.2023.11.004","DOIUrl":"10.1016/j.enbenv.2023.11.004","url":null,"abstract":"<div><div>Passive solar house technology has been spread for many farmers and herdsmen to improve the indoor thermal environment in Tibetan. However, due to lackage of fuels and arid cold in winter, dry cow dung and coal are popularly fired in stove in passive solar houses, which leads to indoor air pollution and poor indoor comfort. For improving indoor thermal comfort of Tibetan, an active solar heating system which consists of 7 sets of tandem solar water heaters with 30 glass evacuated solar tubes, low temperature floor heating and circulation controller was developed and tested for a common house without insulation in Gan-nan Tibetan area. Its indoor environment was compared and evaluated by PMV-PPD and LPD method to that of the same passive solar house heated by coal stove. On sunny, cloudy and snow days, the active solar heating system provided 113.1, 46.4 and 26.3 kWh of heat to room. The indoor humidity and wind speed of the experimental building were better. The indoor temperatures were 17.2-20.7, 14.9-20.5 and 11.0-14.8°C, while the compared building were 8.9-14.8, 10.1-12.1 and 7.2-10.5°C. The maximum temperature difference between head and ankle were 1.7, 1.6 and 0.9℃, and the compared building were 4, 4 and 4.7℃. The PMV-PPD on sunny day were class I and II; on cloudy day were class I, II and III; on snow day was class III. On sunny and cloudy days, the LPD were class I, on snow day was class I, II and III. The PMV-PPD and LPD for typical days of the compared building were class III. During the 179 days, the mean indoor temperature exceeded 14 ℃ for 81 days, the solar active heating system provided 12471 kWh of heat to room. The CO<sub>2</sub> emission reduction was 12905 kg. The system's dynamic payback period were 2.57 years.</div></div>","PeriodicalId":33659,"journal":{"name":"Energy and Built Environment","volume":"6 2","pages":"Pages 285-296"},"PeriodicalIF":0.0,"publicationDate":"2023-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139299405","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-14DOI: 10.1016/j.enbenv.2023.11.003
Charbel Habchi , Fadl Moukalled , Mahmoud Khaled
This paper investigates the potential of utilizing air-conditioning (AC) system exhaust to cool Photo Voltaic (PV) panels, leading to improved efficiency. Additionally, the study explores harnessing the heat emitted from the PV modules for thermal applications. Numerical simulations demonstrate that this cooling method can enhance PV module efficiency by 5% to 50% compared to non-cooled scenarios. Moreover, the recovered hot air leaving the PV panels is directed to a dishwasher for drying purpose, thereby optimizing the overall energy utilization of the proposed system. An energetic and exergetic analysis of the recuperated thermal energy showcases its exceptional thermal efficiency, ranging from 98% to 45%, which aligns with values reported in existing literature. The exergetic efficiency of the suggested system falls between 5.2% and 1%, consistent with the range of values documented in previous studies. By exploiting AC system exhaust and waste heat, this new approach can significantly enhance the performance of PV panels and promote energy efficiency. Implementing this technology could prove instrumental in sustainable energy applications.
{"title":"Dual Harnessing of Air Conditioning Exhaust: PV Cooling and Dishwasher Drying","authors":"Charbel Habchi , Fadl Moukalled , Mahmoud Khaled","doi":"10.1016/j.enbenv.2023.11.003","DOIUrl":"10.1016/j.enbenv.2023.11.003","url":null,"abstract":"<div><div>This paper investigates the potential of utilizing air-conditioning (AC) system exhaust to cool Photo Voltaic (PV) panels, leading to improved efficiency. Additionally, the study explores harnessing the heat emitted from the PV modules for thermal applications. Numerical simulations demonstrate that this cooling method can enhance PV module efficiency by 5% to 50% compared to non-cooled scenarios. Moreover, the recovered hot air leaving the PV panels is directed to a dishwasher for drying purpose, thereby optimizing the overall energy utilization of the proposed system. An energetic and exergetic analysis of the recuperated thermal energy showcases its exceptional thermal efficiency, ranging from 98% to 45%, which aligns with values reported in existing literature. The exergetic efficiency of the suggested system falls between 5.2% and 1%, consistent with the range of values documented in previous studies. By exploiting AC system exhaust and waste heat, this new approach can significantly enhance the performance of PV panels and promote energy efficiency. Implementing this technology could prove instrumental in sustainable energy applications.</div></div>","PeriodicalId":33659,"journal":{"name":"Energy and Built Environment","volume":"6 2","pages":"Pages 277-284"},"PeriodicalIF":0.0,"publicationDate":"2023-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135763901","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Solar photovoltaic (PV) cells have emerged as the primary technology for producing green electricity. This innovation harnesses direct sunlight to generate power and its flexibility of installation has drawn significant investment in PV panels. Despite numerous benefits, these cells are hindered by a decline in efficiency caused by elevated cell temperature. As such, researchers have undertaken extensive investigations into possible solutions aimed at enhancing the performance of photovoltaic cells using diverse techniques. This review paper provides a thorough analysis of cooling techniques for photovoltaic panels. It encompasses both passive and active cooling methods, including water and air cooling, phase-change materials, and various diverse approaches. Within each category, it delves into detailed sub-categories, such as evaporative cooling, water immersion, floating systems, water pipes, cooling channels, water sprayers, jet impingement, geothermal cooling, and natural convection enhanced by PV designs. It also covers forced convection using cooling ducts, heat sinks, and air collectors, alongside the integration of Phase Change Materials (PCMs), nanofluids, radiative cooling, thermoelectric methods, heat pipes, heat pumps, and other innovative techniques. Each of these approaches is illustrated with specific schematics and thoroughly discussed and compared. Furthermore, this paper introduces an original classification system for these cooling methods applied to photovoltaic panels, offering valuable guidance for future research and insights into improving efficiency.
{"title":"Advancements in cooling techniques for enhanced efficiency of solar photovoltaic panels: A detailed comprehensive review and innovative classification","authors":"Mohamad Abou Akrouch , Khaled Chahine , Jalal Faraj , Farouk Hachem , Cathy Castelain , Mahmoud Khaled","doi":"10.1016/j.enbenv.2023.11.002","DOIUrl":"10.1016/j.enbenv.2023.11.002","url":null,"abstract":"<div><div>Solar photovoltaic (PV) cells have emerged as the primary technology for producing green electricity. This innovation harnesses direct sunlight to generate power and its flexibility of installation has drawn significant investment in PV panels. Despite numerous benefits, these cells are hindered by a decline in efficiency caused by elevated cell temperature. As such, researchers have undertaken extensive investigations into possible solutions aimed at enhancing the performance of photovoltaic cells using diverse techniques. This review paper provides a thorough analysis of cooling techniques for photovoltaic panels. It encompasses both passive and active cooling methods, including water and air cooling, phase-change materials, and various diverse approaches. Within each category, it delves into detailed sub-categories, such as evaporative cooling, water immersion, floating systems, water pipes, cooling channels, water sprayers, jet impingement, geothermal cooling, and natural convection enhanced by PV designs. It also covers forced convection using cooling ducts, heat sinks, and air collectors, alongside the integration of Phase Change Materials (PCMs), nanofluids, radiative cooling, thermoelectric methods, heat pipes, heat pumps, and other innovative techniques. Each of these approaches is illustrated with specific schematics and thoroughly discussed and compared. Furthermore, this paper introduces an original classification system for these cooling methods applied to photovoltaic panels, offering valuable guidance for future research and insights into improving efficiency.</div></div>","PeriodicalId":33659,"journal":{"name":"Energy and Built Environment","volume":"6 2","pages":"Pages 248-276"},"PeriodicalIF":0.0,"publicationDate":"2023-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135411434","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-03DOI: 10.1016/j.enbenv.2023.10.007
Madhavan Vasudevan , Francesco Pilla , Aonghus McNabola
Traffic emission impacts the air quality at both the road surface and in near road buildings. Previous research has examined the benefit of using roof-level wind catchers to reduce concentration along building facades in urban environments. Although roof-level interventions are more effective in improving the street canyon air quality in its entirety, localized re-distributions that detrimentally affect specific regions in and around the street canyons are unavoidable. In the current work, a deflector system that can adjust its position and orientation to changing ambient conditions is introduced to ensure that no particular region perpetually experiences compromised air quality. At optimal roof-level positions, the wind deflectors resulted in a local maximum and minimum of pollution removal through mean flow-induced fluxes and overall canyon concentrations respectively. In this study, the potential of the wind deflectors was first demonstrated using 2D Computational Fluid Dynamics (CFD) investigations. A maximum reduction in overall canyon concentration of 2.84 fold was predicted when the deflector was placed 2 m from the leeward walls. Subsequently, the benefit of the dynamic nature of the intervention and the efficacy of the same in a more realistic 3D city-type environment was demonstrated by considering two different pollution source conditions. The wind deflectors performed modestly for the Cross Road Pollution (CRP) source model by reducing 7%, 11% and 13% of CO exposure on the leeward wall, upwind side wall and downwind side wall without affecting the windward wall of the target street canyon. Whereas for the Side Road Pollution (SRP) source model, it reduced 91%, 32% and 34% on the same with a 17% reduction on the windward wall of the target street canyon. Finally, the concept of an adjustable deflector system was demonstrated to mitigate prolonged high exposure for building occupants exposed to changing traffic emission sources via all the surrounding building facades and at the ground.
{"title":"Enhancing ventilation in street canyons using adjustable roof-level wind flow deflectors","authors":"Madhavan Vasudevan , Francesco Pilla , Aonghus McNabola","doi":"10.1016/j.enbenv.2023.10.007","DOIUrl":"10.1016/j.enbenv.2023.10.007","url":null,"abstract":"<div><div>Traffic emission impacts the air quality at both the road surface and in near road buildings. Previous research has examined the benefit of using roof-level wind catchers to reduce concentration along building facades in urban environments. Although roof-level interventions are more effective in improving the street canyon air quality in its entirety, localized re-distributions that detrimentally affect specific regions in and around the street canyons are unavoidable. In the current work, a deflector system that can adjust its position and orientation to changing ambient conditions is introduced to ensure that no particular region perpetually experiences compromised air quality. At optimal roof-level positions, the wind deflectors resulted in a local maximum and minimum of pollution removal through mean flow-induced fluxes and overall canyon concentrations respectively. In this study, the potential of the wind deflectors was first demonstrated using 2D Computational Fluid Dynamics (CFD) investigations. A maximum reduction in overall canyon concentration of 2.84 fold was predicted when the deflector was placed 2 m from the leeward walls. Subsequently, the benefit of the dynamic nature of the intervention and the efficacy of the same in a more realistic 3D city-type environment was demonstrated by considering two different pollution source conditions. The wind deflectors performed modestly for the Cross Road Pollution (CRP) source model by reducing 7%, 11% and 13% of CO exposure on the leeward wall, upwind side wall and downwind side wall without affecting the windward wall of the target street canyon. Whereas for the Side Road Pollution (SRP) source model, it reduced 91%, 32% and 34% on the same with a 17% reduction on the windward wall of the target street canyon. Finally, the concept of an adjustable deflector system was demonstrated to mitigate prolonged high exposure for building occupants exposed to changing traffic emission sources via all the surrounding building facades and at the ground.</div></div>","PeriodicalId":33659,"journal":{"name":"Energy and Built Environment","volume":"6 2","pages":"Pages 201-218"},"PeriodicalIF":0.0,"publicationDate":"2023-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135410603","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-02DOI: 10.1016/j.enbenv.2023.11.001
Xiangfei Kong, Ruiming Nie, Jianjuan Yuan
Liquid leakage of PCM and thermophysical performance defects seriously affect the application prospect of PCMs. Aerogels provide an excellent solution for packaging and performance improvement of PCMs with its ultra-high specific surface area and low density and give PCMs other functions besides energy storage, such as energy conversion (photothermal/electrothermal conversion, magnetic thermal/acoustic thermal conversion), thermal management (battery thermal management, electronic thermal management), thermal infrared stealth, building materials, etc. In this paper, firstly, the preparation method and multifunctional response mechanism of aerogel-based PCMs are systematically described, and the improvement of thermophysical and mechanical properties of various aerogel-based PCMs is reviewed from the perspective of aerogel preparation. Then, according to the different application scenarios of aerogel-based PCMs, the advanced functions of aerogel-based PCMs are reviewed, and the multifunctional effects of different materials in aerogel-based PCMs are compared. Finally, some insightful guidance and suggestions for the research and development of aerogel-based PCMs are put forward.
{"title":"A review of shape stabilized aerogel-based phase change materials for preparation, classification and applications","authors":"Xiangfei Kong, Ruiming Nie, Jianjuan Yuan","doi":"10.1016/j.enbenv.2023.11.001","DOIUrl":"10.1016/j.enbenv.2023.11.001","url":null,"abstract":"<div><div>Liquid leakage of PCM and thermophysical performance defects seriously affect the application prospect of PCMs. Aerogels provide an excellent solution for packaging and performance improvement of PCMs with its ultra-high specific surface area and low density and give PCMs other functions besides energy storage, such as energy conversion (photothermal/electrothermal conversion, magnetic thermal/acoustic thermal conversion), thermal management (battery thermal management, electronic thermal management), thermal infrared stealth, building materials, etc. In this paper, firstly, the preparation method and multifunctional response mechanism of aerogel-based PCMs are systematically described, and the improvement of thermophysical and mechanical properties of various aerogel-based PCMs is reviewed from the perspective of aerogel preparation. Then, according to the different application scenarios of aerogel-based PCMs, the advanced functions of aerogel-based PCMs are reviewed, and the multifunctional effects of different materials in aerogel-based PCMs are compared. Finally, some insightful guidance and suggestions for the research and development of aerogel-based PCMs are put forward.</div></div>","PeriodicalId":33659,"journal":{"name":"Energy and Built Environment","volume":"6 2","pages":"Pages 230-247"},"PeriodicalIF":0.0,"publicationDate":"2023-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135325443","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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