B. Sayad, Y. Menni, Ayman Imam, Ahmad Fallatah, Kamil Faisal, A. M. Abed, H. Alhubashi, I. Hegazy
The urban heat island (UHI) is a physical climatic phenomenon, its effects in the built-up areas can be observed in terms of air temperatures above the atmosphere, as well as in terms of thermal comfort under the urban canopy. This study aims to carry out a diurnal characterization of the atmospheric urban heat island over the agglomeration of Guelma, Algeria during summertime. The characterization is organized into three main steps. First, quantifying the UHI intensity. Second, highlighting the factors contributing to affect the thermal environment in downtown Guelma and fianly, defining an appropriate scale to measure it over Gualma’s agglomeration of Guelma. The UHI quantification was done by calculating the positive differences of urban temperatures in daytime based on in-situ approach and static approach. The results indicate that the maximum daily difference reached 4.8°C to 5.1°C with a positive difference of 6.1° at 10:00 a.m. and 6.4°C at noon, which means that Guelma’s agglomeration is affected by the atmospheric urban heat island phenomenon. Depending on the difference of urban temperatures, we have defined appropriate scale to quantify the intensity of UHI phenomenon over Guelma’s agglomeration: ${UHI}_{intensity}=0.3688vectimes Delta {T}_{boldsymbol{urb}}+3.3157.$
{"title":"Diurnal Characterization of the Atmospheric Urban Heat Island over Urban Hot Agglomerations","authors":"B. Sayad, Y. Menni, Ayman Imam, Ahmad Fallatah, Kamil Faisal, A. M. Abed, H. Alhubashi, I. Hegazy","doi":"10.1093/ijlct/ctad025","DOIUrl":"https://doi.org/10.1093/ijlct/ctad025","url":null,"abstract":"\u0000 The urban heat island (UHI) is a physical climatic phenomenon, its effects in the built-up areas can be observed in terms of air temperatures above the atmosphere, as well as in terms of thermal comfort under the urban canopy. This study aims to carry out a diurnal characterization of the atmospheric urban heat island over the agglomeration of Guelma, Algeria during summertime. The characterization is organized into three main steps. First, quantifying the UHI intensity. Second, highlighting the factors contributing to affect the thermal environment in downtown Guelma and fianly, defining an appropriate scale to measure it over Gualma’s agglomeration of Guelma. The UHI quantification was done by calculating the positive differences of urban temperatures in daytime based on in-situ approach and static approach. The results indicate that the maximum daily difference reached 4.8°C to 5.1°C with a positive difference of 6.1° at 10:00 a.m. and 6.4°C at noon, which means that Guelma’s agglomeration is affected by the atmospheric urban heat island phenomenon. Depending on the difference of urban temperatures, we have defined appropriate scale to quantify the intensity of UHI phenomenon over Guelma’s agglomeration: ${UHI}_{intensity}=0.3688vectimes Delta {T}_{boldsymbol{urb}}+3.3157.$","PeriodicalId":14118,"journal":{"name":"International Journal of Low-carbon Technologies","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43033852","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In pandemic periods such as COVID-19, economic and sociological problems threaten human life and public order on a global scale. In these periods, the use of solar powered heating-cooling systems to meet the thermal needs of the hospitals and to provide the thermal comfort conditions offer important solutions for the elimination of technical, economic and environmental problems related to energy supply. In this study, covering the heating, cooling and hot water supply of a sample hospital building for the three largest cities of Turkey with a novel solar powered Li-Cl absorption heat pump system was investigated using the TRNSYS simulation program. The use of a unique NH3-H2O resorption system as a solar powered auxiliary system was also investigated. It was determined that the total annual hot water and cooling needs of the hospital buildings in all three provinces are supplied almost completely with the solar energy powered system without compromising the hygiene and thermal comfort of the occupants and the average annual solar fraction of total heating demands are calculated as 50%, 54% and 65% for İstanbul, Ankara and İzmir, respectively. In addition, depending on the use of solar energy, it has been observed that annually 126 tons of CO2 emissions were saved and an economic saving of 524 375 TL was achieved in total. Considering the problems about the energy supply during the epidemic periods, it was concluded that meeting the energy requirements of hospitals with clean, renewable and independent energy source will provide significant benefits to the countries.
{"title":"Investigation of Solar Powered Sorption Cooling and Heating Systems to Supply Hospital’s Thermal Requirements in Pandemic Periods","authors":"Bilsay Pastakkaya","doi":"10.1093/ijlct/ctad026","DOIUrl":"https://doi.org/10.1093/ijlct/ctad026","url":null,"abstract":"\u0000 In pandemic periods such as COVID-19, economic and sociological problems threaten human life and public order on a global scale. In these periods, the use of solar powered heating-cooling systems to meet the thermal needs of the hospitals and to provide the thermal comfort conditions offer important solutions for the elimination of technical, economic and environmental problems related to energy supply. In this study, covering the heating, cooling and hot water supply of a sample hospital building for the three largest cities of Turkey with a novel solar powered Li-Cl absorption heat pump system was investigated using the TRNSYS simulation program. The use of a unique NH3-H2O resorption system as a solar powered auxiliary system was also investigated. It was determined that the total annual hot water and cooling needs of the hospital buildings in all three provinces are supplied almost completely with the solar energy powered system without compromising the hygiene and thermal comfort of the occupants and the average annual solar fraction of total heating demands are calculated as 50%, 54% and 65% for İstanbul, Ankara and İzmir, respectively. In addition, depending on the use of solar energy, it has been observed that annually 126 tons of CO2 emissions were saved and an economic saving of 524 375 TL was achieved in total. Considering the problems about the energy supply during the epidemic periods, it was concluded that meeting the energy requirements of hospitals with clean, renewable and independent energy source will provide significant benefits to the countries.","PeriodicalId":14118,"journal":{"name":"International Journal of Low-carbon Technologies","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46464722","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Usha Pawar, K. Bhole, Ankit D. Oza, H. Panchal, Mohammad Asif Shah, Mustafa Musa Jaber
This study presents the design and fabrication of an urban solar food cooking system with a phase change material (PCM) as a heat storage tank. The effort has been taken to test the system experimentally and explore its thermal performance under actual climatic conditions of Mumbai, India. The solar heat energy is stored in the tank using commercial grade Erythritol as PCM in current research work. A heat exchanger is well designed and fabricated to regulate the flow of solar heat energy from the storage tank to the cooking vessel, similar to the domestic Liquefied Petroleum Gas (LPG) cooking system. This solar cooker is designed to cook food twice a day for four family members (Equivalent to the energy of 5000 KJ). Cooking experiments were conducted on 19th April 2019 for the afternoon and evening slots with rice and potato as cooking loads, respectively. The time taken for cooking rice and potato are from 12:30 pm to 12:52 pm (22 minute) and from 05:30 pm to 05:59 pm (29 minutes), respectively. The heat transfer rate was also observed at different storage tanks and cooking unit points. The experiments show cooking is possible twice a day and considered as convenient as domestic LPG stoves. Furthermore, it was found that comparatively less time was required for cooking food than the other existing solar cookers.
{"title":"A case study on the design and development of solar food cooking system with a PCM as a heat storage unit","authors":"Usha Pawar, K. Bhole, Ankit D. Oza, H. Panchal, Mohammad Asif Shah, Mustafa Musa Jaber","doi":"10.1093/ijlct/ctad002","DOIUrl":"https://doi.org/10.1093/ijlct/ctad002","url":null,"abstract":"\u0000 This study presents the design and fabrication of an urban solar food cooking system with a phase change material (PCM) as a heat storage tank. The effort has been taken to test the system experimentally and explore its thermal performance under actual climatic conditions of Mumbai, India. The solar heat energy is stored in the tank using commercial grade Erythritol as PCM in current research work. A heat exchanger is well designed and fabricated to regulate the flow of solar heat energy from the storage tank to the cooking vessel, similar to the domestic Liquefied Petroleum Gas (LPG) cooking system. This solar cooker is designed to cook food twice a day for four family members (Equivalent to the energy of 5000 KJ). Cooking experiments were conducted on 19th April 2019 for the afternoon and evening slots with rice and potato as cooking loads, respectively. The time taken for cooking rice and potato are from 12:30 pm to 12:52 pm (22 minute) and from 05:30 pm to 05:59 pm (29 minutes), respectively. The heat transfer rate was also observed at different storage tanks and cooking unit points. The experiments show cooking is possible twice a day and considered as convenient as domestic LPG stoves. Furthermore, it was found that comparatively less time was required for cooking food than the other existing solar cookers.","PeriodicalId":14118,"journal":{"name":"International Journal of Low-carbon Technologies","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49369713","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Shishir Gautam, Ashish Sedai, Rabin Dhakal, B. Sedai, S. Pol
In-pipe hydroelectric power generation is a relatively new clean energy power generation technology. This new clean energy technology has been identified to be feasible after successful commercial installation in different parts of the world. Several researchers worldwide have studied the optimal turbine type, the optimal number of blades in turbine, introduction of suitable deflector, etc. for this technology. However, the effect of the turbine’s position relative to the upstream deflector on its performance has not been studied so far. This research encompasses a numerical study of the in-pipe hydroelectric power generation turbine to identify the optimal position of the turbine from the deflector. The study was performed for a 160 mm diameter pipeline and a 126 mm turbine height. The research aims to predict the behavior of larger diameter pipelines for commercial installation based on the result obtained from this study. The numerical study was performed for a hollow-type drag turbine at 6 different rotational speeds and 10 different turbine positions. The results suggest that the performance characteristics of drag-type turbine are erratic, thus leaving little space to draw a firm conclusion about the turbine’s performance. However, there was an increase in pressure difference, head, and available theoretical power with the increase in rotational speed for all the positions. It was also found that such turbines were generally more efficient at slightly higher rotational speeds, i.e. speed greater than 40 rad/s, and at about the distance of 0.65D (where D is the pipe diameter) between deflector’s eye and turbine.
{"title":"CFD Analysis of gravity-fed drag-type in-pipe water turbine to determine the optimal deflector-to-turbine position","authors":"Shishir Gautam, Ashish Sedai, Rabin Dhakal, B. Sedai, S. Pol","doi":"10.1093/ijlct/ctac138","DOIUrl":"https://doi.org/10.1093/ijlct/ctac138","url":null,"abstract":"\u0000 In-pipe hydroelectric power generation is a relatively new clean energy power generation technology. This new clean energy technology has been identified to be feasible after successful commercial installation in different parts of the world. Several researchers worldwide have studied the optimal turbine type, the optimal number of blades in turbine, introduction of suitable deflector, etc. for this technology. However, the effect of the turbine’s position relative to the upstream deflector on its performance has not been studied so far. This research encompasses a numerical study of the in-pipe hydroelectric power generation turbine to identify the optimal position of the turbine from the deflector. The study was performed for a 160 mm diameter pipeline and a 126 mm turbine height. The research aims to predict the behavior of larger diameter pipelines for commercial installation based on the result obtained from this study. The numerical study was performed for a hollow-type drag turbine at 6 different rotational speeds and 10 different turbine positions. The results suggest that the performance characteristics of drag-type turbine are erratic, thus leaving little space to draw a firm conclusion about the turbine’s performance. However, there was an increase in pressure difference, head, and available theoretical power with the increase in rotational speed for all the positions. It was also found that such turbines were generally more efficient at slightly higher rotational speeds, i.e. speed greater than 40 rad/s, and at about the distance of 0.65D (where D is the pipe diameter) between deflector’s eye and turbine.","PeriodicalId":14118,"journal":{"name":"International Journal of Low-carbon Technologies","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47753241","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Offshore wind power is considered a promising renewable energy, unfortunately, its weighted average levelized cost of electricity (LCOE) is still too high to compete with renewable energies such as photovoltaics, this is in large part due to the high construction cost of offshore wind power, even though it has fallen substantially with technological advances and the accumulation of experience. This paper optimizes the cost from two aspects, since large-scale wind farms have better bargaining and scheduling power, we analyze in detail the relationship between the cost of different key components and the scale of the wind farm, and, if the decommissioned wind farm chooses to repower, costs such as cables and foundations can be saved, which can further reduce the costs. Our studies show that compared to a 400 MW offshore wind farm, a 1,000 MW can reduce the unit cost by about 10.3%, and its cost is about 13,239 RMB/kW, if repowering is chosen, a further reduction of about 28.6%, its cost is about 9,450 RMB/kW. We recommend using larger offshore wind farms and choosing repowering after they are decommissioned to get better economics.
{"title":"Study on the optimization strategy of offshore wind power","authors":"Jing Wang, Xiongfei Wei, Ronaldo Juanatas","doi":"10.1093/ijlct/ctad024","DOIUrl":"https://doi.org/10.1093/ijlct/ctad024","url":null,"abstract":"\u0000 Offshore wind power is considered a promising renewable energy, unfortunately, its weighted average levelized cost of electricity (LCOE) is still too high to compete with renewable energies such as photovoltaics, this is in large part due to the high construction cost of offshore wind power, even though it has fallen substantially with technological advances and the accumulation of experience. This paper optimizes the cost from two aspects, since large-scale wind farms have better bargaining and scheduling power, we analyze in detail the relationship between the cost of different key components and the scale of the wind farm, and, if the decommissioned wind farm chooses to repower, costs such as cables and foundations can be saved, which can further reduce the costs. Our studies show that compared to a 400 MW offshore wind farm, a 1,000 MW can reduce the unit cost by about 10.3%, and its cost is about 13,239 RMB/kW, if repowering is chosen, a further reduction of about 28.6%, its cost is about 9,450 RMB/kW. We recommend using larger offshore wind farms and choosing repowering after they are decommissioned to get better economics.","PeriodicalId":14118,"journal":{"name":"International Journal of Low-carbon Technologies","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45359985","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Solar photovoltaic (PV) is considered a very promising technology, and PV-lithium-ion battery energy storage is widely used to obtain smoother power output. In this paper, we propose a battery equalization circuit and control strategy to improve the performance of lithium-ion batteries. In the equalization circuit, the passive equalization and active equalization circuits are combined, and the active equalization circuit used is simple and has high performance, while in the equalization strategy, since the system works 24h a day, the equalization speed is sacrificed to obtain a smaller temperature rise by adjusting the duty cycle of the passive equalization metal-oxide-semiconductor field-effect transistors (MOSFETs), and by calculating the state of charge (SOC) instead of the voltage to obtain better performance. The proposed circuit and strategy can not only achieve the goal of battery equalization, while turn on 4 batteries at the same time and the temperature rise of passive equalization is only 1°C for about 1.5h, compared with the traditional equalization control strategy with 8mV voltage error, the proposed strategy is only 3mV, which has better performance.
{"title":"Lithium-ion battery equalization circuit and control strategy for photovoltaic energy storage applications","authors":"Haiyan Yao, Aung Thinzar","doi":"10.1093/ijlct/ctad017","DOIUrl":"https://doi.org/10.1093/ijlct/ctad017","url":null,"abstract":"\u0000 Solar photovoltaic (PV) is considered a very promising technology, and PV-lithium-ion battery energy storage is widely used to obtain smoother power output. In this paper, we propose a battery equalization circuit and control strategy to improve the performance of lithium-ion batteries. In the equalization circuit, the passive equalization and active equalization circuits are combined, and the active equalization circuit used is simple and has high performance, while in the equalization strategy, since the system works 24h a day, the equalization speed is sacrificed to obtain a smaller temperature rise by adjusting the duty cycle of the passive equalization metal-oxide-semiconductor field-effect transistors (MOSFETs), and by calculating the state of charge (SOC) instead of the voltage to obtain better performance. The proposed circuit and strategy can not only achieve the goal of battery equalization, while turn on 4 batteries at the same time and the temperature rise of passive equalization is only 1°C for about 1.5h, compared with the traditional equalization control strategy with 8mV voltage error, the proposed strategy is only 3mV, which has better performance.","PeriodicalId":14118,"journal":{"name":"International Journal of Low-carbon Technologies","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46817669","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Shuhan Liu, Jiahui Wang, Li Meng, Chenxi Hu, Xi Meng
Light-weight materials are commonly used in high-rise buildings to reduce the building weight, but their thermal inertia will increase the fluctuation of air-conditioning and heating load and reduce indoor thermal comfort. Phase-Change Material (PCM) is employed to improve the thermal behavior by latent thermal storage, but its location has the obvious impact on the thermal behavior improvement of the light-weight wall. According to this condition, by taking the common multi-layer wall as a reference, three walls were built with different locations of the PCM layer, including locating the PCM layer in inner side, locating the PCM layer in outer side, and distributing PCM uniformly into foamed concrete. The dynamic heat transfer model with the phase change had built and verified by an experiment. Numerical results showed locating the PCM layer in inner side is the best in three locations and followed by distributing PCM uniformly into foamed concrete, while locating the PCM layer in outer side is the worst in the spite of the high liquid fraction variation. Locating the PCM layer in inner side can lower the attenuation factor by 101.25% and 33.87%, increase the delay time by 40.00% and 17.14%, reduced by the peak heat flow by 47.69% and 17.28%, compared to locating the PCM layer in outer side and distributing PCM into foamed concrete uniformly.
{"title":"Location of the phase-change material (PCM) layer on thermal performance of light-weight walls","authors":"Shuhan Liu, Jiahui Wang, Li Meng, Chenxi Hu, Xi Meng","doi":"10.1093/ijlct/ctac096","DOIUrl":"https://doi.org/10.1093/ijlct/ctac096","url":null,"abstract":"\u0000 Light-weight materials are commonly used in high-rise buildings to reduce the building weight, but their thermal inertia will increase the fluctuation of air-conditioning and heating load and reduce indoor thermal comfort. Phase-Change Material (PCM) is employed to improve the thermal behavior by latent thermal storage, but its location has the obvious impact on the thermal behavior improvement of the light-weight wall. According to this condition, by taking the common multi-layer wall as a reference, three walls were built with different locations of the PCM layer, including locating the PCM layer in inner side, locating the PCM layer in outer side, and distributing PCM uniformly into foamed concrete. The dynamic heat transfer model with the phase change had built and verified by an experiment. Numerical results showed locating the PCM layer in inner side is the best in three locations and followed by distributing PCM uniformly into foamed concrete, while locating the PCM layer in outer side is the worst in the spite of the high liquid fraction variation. Locating the PCM layer in inner side can lower the attenuation factor by 101.25% and 33.87%, increase the delay time by 40.00% and 17.14%, reduced by the peak heat flow by 47.69% and 17.28%, compared to locating the PCM layer in outer side and distributing PCM into foamed concrete uniformly.","PeriodicalId":14118,"journal":{"name":"International Journal of Low-carbon Technologies","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45771770","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The study shows that oil production and consumption in the various sectors accounted for over 80% of the rising GHG emissions, especially CO2. Additionally, the study examines the solar PV potential of Jeddah, Saudi Arabia, using computational modelling. The results show that the yearly average global horizontal irradiation (GHI), direct normal radiation (DNI), and diffuse horizontal irradiations (DHI) are 2244 kW/m2, 1967 kW/m2, and 863.3 kWh/m2, respectively. Other results are the yearly sum of monthly global tilted irradiation (GTI) and an average yearly daily sum of GTI are 2348.4 (kWh/m2) and 6.44 (kWh/m2), respectively. These results show that Jeddah has huge solar PV potential.
{"title":"Facilitating Greenhouse Gas Emissions Reduction via Photovoltaic Site Characterisation and Deployment in Jeddah, Saudi Arabia","authors":"Fahed A. Aloufi, Riyadh F. Halawani","doi":"10.1093/ijlct/ctac099","DOIUrl":"https://doi.org/10.1093/ijlct/ctac099","url":null,"abstract":"\u0000 The study shows that oil production and consumption in the various sectors accounted for over 80% of the rising GHG emissions, especially CO2. Additionally, the study examines the solar PV potential of Jeddah, Saudi Arabia, using computational modelling. The results show that the yearly average global horizontal irradiation (GHI), direct normal radiation (DNI), and diffuse horizontal irradiations (DHI) are 2244 kW/m2, 1967 kW/m2, and 863.3 kWh/m2, respectively. Other results are the yearly sum of monthly global tilted irradiation (GTI) and an average yearly daily sum of GTI are 2348.4 (kWh/m2) and 6.44 (kWh/m2), respectively. These results show that Jeddah has huge solar PV potential.","PeriodicalId":14118,"journal":{"name":"International Journal of Low-carbon Technologies","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46563378","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Abed, Salema K. Hadrawi, G. Smaisim, A. F. Muftah, F. Jahanbin
Today, the use of solar energy is expanding and developing because this energy is easily available and there are various technologies for producing thermal and electrical energy and cooling. One of the most energy-consuming parts is heating and cooling systems in residential buildings, which includes the major part of energy consumption in buildings. Therefore, in this research, the purpose of this research is to produce thermal energy for the cooling system using solar energy, which was used for analysis using Trnsys software, the purpose of this simulation is to check the thermodynamic parameters of the fluid and economic analysis, taking into account biological pollutants. The environment of the system has been considered. One of the important results of this research is the return on investment of 4 years, in which the required amount of energy supply through the solar system is 0.94.
{"title":"Investigation and Thermo-economic analysis of solar condensation refrigeration","authors":"A. Abed, Salema K. Hadrawi, G. Smaisim, A. F. Muftah, F. Jahanbin","doi":"10.1093/ijlct/ctac103","DOIUrl":"https://doi.org/10.1093/ijlct/ctac103","url":null,"abstract":"\u0000 Today, the use of solar energy is expanding and developing because this energy is easily available and there are various technologies for producing thermal and electrical energy and cooling. One of the most energy-consuming parts is heating and cooling systems in residential buildings, which includes the major part of energy consumption in buildings. Therefore, in this research, the purpose of this research is to produce thermal energy for the cooling system using solar energy, which was used for analysis using Trnsys software, the purpose of this simulation is to check the thermodynamic parameters of the fluid and economic analysis, taking into account biological pollutants. The environment of the system has been considered. One of the important results of this research is the return on investment of 4 years, in which the required amount of energy supply through the solar system is 0.94.","PeriodicalId":14118,"journal":{"name":"International Journal of Low-carbon Technologies","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41441167","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Indirectly estimating global solar radiation is strongly nonlinear and needs to be addressed by machine learning. Sequentially developing a machine learning model can be very time consuming. Moreover, whether and how the exogenous meteorological, geographical, and temporal variables affect regression accuracy still hasn’t been well understood. This paper evaluates parallelized support vector regression (SVR) and nearest neighbor regression (NNR) models for estimating daily global solar radiation of the humid subtropical region in China using existing Python libraries on a multi-core central processing unit (CPU) and a graphical processing unit (GPU). Seven input variations are studied. Two variations are commonly adopted in literature, four variations contain meteorological, geographical, and/or temporal features with bounded Pearson correlation coefficients (PCCs), and the other variation simply include all the available features. Experimental results demonstrate that: SVR and NNR are equally powerful for nonlinear regression, and the variation comprising features with absolute PCCs no less than 0.3 (i.e. just all the meteorological features) is able to achieve most accurate estimation; the GPU-parallelized SVR model can accelerate parameter calibration and prediction; compared with the CPU-parallelized and GPU-parallelized SVR models, the GPU-parallelized NNR model is much more efficient and rather more scalable with the increment of the number of data samples; and the CPU-parallelized NNR model consumes quite less parameter calibration time than the GPU-parallelized NNR model, owing to different methods adopted for determining distances and significant time wasted by the GPU-parallelized NNR model on repeatedly calculating required information during crossvalidation.
{"title":"Evaluating parallelized support vector regression and nearest neighbor regression with different input variations for estimating daily global solar radiation of the humid subtropical region in China","authors":"Xiang Yu","doi":"10.1093/ijlct/ctad005","DOIUrl":"https://doi.org/10.1093/ijlct/ctad005","url":null,"abstract":"\u0000 Indirectly estimating global solar radiation is strongly nonlinear and needs to be addressed by machine learning. Sequentially developing a machine learning model can be very time consuming. Moreover, whether and how the exogenous meteorological, geographical, and temporal variables affect regression accuracy still hasn’t been well understood. This paper evaluates parallelized support vector regression (SVR) and nearest neighbor regression (NNR) models for estimating daily global solar radiation of the humid subtropical region in China using existing Python libraries on a multi-core central processing unit (CPU) and a graphical processing unit (GPU). Seven input variations are studied. Two variations are commonly adopted in literature, four variations contain meteorological, geographical, and/or temporal features with bounded Pearson correlation coefficients (PCCs), and the other variation simply include all the available features. Experimental results demonstrate that: SVR and NNR are equally powerful for nonlinear regression, and the variation comprising features with absolute PCCs no less than 0.3 (i.e. just all the meteorological features) is able to achieve most accurate estimation; the GPU-parallelized SVR model can accelerate parameter calibration and prediction; compared with the CPU-parallelized and GPU-parallelized SVR models, the GPU-parallelized NNR model is much more efficient and rather more scalable with the increment of the number of data samples; and the CPU-parallelized NNR model consumes quite less parameter calibration time than the GPU-parallelized NNR model, owing to different methods adopted for determining distances and significant time wasted by the GPU-parallelized NNR model on repeatedly calculating required information during crossvalidation.","PeriodicalId":14118,"journal":{"name":"International Journal of Low-carbon Technologies","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42281446","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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