The Experts below are selected from a list of 54 Experts worldwide ranked by ideXlab platform
M Z Ullah - One of the best experts on this subject based on the ideXlab platform.
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the performance of a solar assisted heat pump water heating system
Applied Thermal Engineering, 2001Co-Authors: M N A Hawlader, S K Chou, M Z UllahAbstract:Analytical and experimental studies were performed on a solar assisted heat pump water heating system, where unglazed, flat plate solar collectors acted as an evaporator for the refrigerant R-134a. The system was designed and fabricated locally, and operated under meteorological conditions of Singapore. The results obtained from simulation are used for the optimum design of the system and enable determination of Compressor work, solar fraction and auxiliary energy required for a particular application. To ensure proper matching between the collector/evaporator load and Compressor Capacity, a variable speed Compressor was used. Due to high ambient temperature in Singapore, evaporator can be operated at a higher temperature, without exceeding the desired design pressure limit of the Compressor, resulting in an improved thermal performance of the system. Results show that, when water temperature in the condenser tank increases with time, the condensing temperature, also, increases, and the corresponding COP and collector efficiency values decline. Average values of COP ranged from about 4 to 9 and solar collector efficiency was found to vary between 40% and 75% for water temperatures in the condenser tank varying between 30°C and 50°C. A simulation model has been developed to analyse the thermal performance of the system. A series of numerical experiments have been performed to identify important variables. These results are compared with experimental values and a good agreement between predicted and experimental results has been found. Results indicate that the performance of the system is influenced significantly by collector area, speed of the Compressor, and solar irradiation. An economic analysis indicates a minimum payback period of about two years for the system.
Shiming Deng - One of the best experts on this subject based on the ideXlab platform.
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a simulation study on the operating performance of a solar air source heat pump water heater
Applied Thermal Engineering, 2006Co-Authors: Guoying Xu, Xiaosong Zhang, Shiming DengAbstract:Abstract A simulation study on the operating performance of a new type of solar–air source heat pump water heater (SAS-HPWH) has been presented. The SAS-HPWH used a specially designed flat-plate heat collector/evaporator with spiral-finned tubes to obtain energy from both solar irradiation and ambient air for hot water heating. Using the meteorological data in Nanjing, China, the simulation results based on 150 L water heating Capacity showed that such a SAS-HPWH can heat water up to 55 °C efficiently under various weather conditions all year around. In this simulation study, the influences of solar radiation, ambient temperature and Compressor Capacity on the performance of the SAS-HPWH were analyzed. In order to improve the overall operating performance, the use of a variable-Capacity Compressor has been proposed.
M N A Hawlader - One of the best experts on this subject based on the ideXlab platform.
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the performance of a solar assisted heat pump water heating system
Applied Thermal Engineering, 2001Co-Authors: M N A Hawlader, S K Chou, M Z UllahAbstract:Analytical and experimental studies were performed on a solar assisted heat pump water heating system, where unglazed, flat plate solar collectors acted as an evaporator for the refrigerant R-134a. The system was designed and fabricated locally, and operated under meteorological conditions of Singapore. The results obtained from simulation are used for the optimum design of the system and enable determination of Compressor work, solar fraction and auxiliary energy required for a particular application. To ensure proper matching between the collector/evaporator load and Compressor Capacity, a variable speed Compressor was used. Due to high ambient temperature in Singapore, evaporator can be operated at a higher temperature, without exceeding the desired design pressure limit of the Compressor, resulting in an improved thermal performance of the system. Results show that, when water temperature in the condenser tank increases with time, the condensing temperature, also, increases, and the corresponding COP and collector efficiency values decline. Average values of COP ranged from about 4 to 9 and solar collector efficiency was found to vary between 40% and 75% for water temperatures in the condenser tank varying between 30°C and 50°C. A simulation model has been developed to analyse the thermal performance of the system. A series of numerical experiments have been performed to identify important variables. These results are compared with experimental values and a good agreement between predicted and experimental results has been found. Results indicate that the performance of the system is influenced significantly by collector area, speed of the Compressor, and solar irradiation. An economic analysis indicates a minimum payback period of about two years for the system.
Guoying Xu - One of the best experts on this subject based on the ideXlab platform.
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a simulation study on the operating performance of a solar air source heat pump water heater
Applied Thermal Engineering, 2006Co-Authors: Guoying Xu, Xiaosong Zhang, Shiming DengAbstract:Abstract A simulation study on the operating performance of a new type of solar–air source heat pump water heater (SAS-HPWH) has been presented. The SAS-HPWH used a specially designed flat-plate heat collector/evaporator with spiral-finned tubes to obtain energy from both solar irradiation and ambient air for hot water heating. Using the meteorological data in Nanjing, China, the simulation results based on 150 L water heating Capacity showed that such a SAS-HPWH can heat water up to 55 °C efficiently under various weather conditions all year around. In this simulation study, the influences of solar radiation, ambient temperature and Compressor Capacity on the performance of the SAS-HPWH were analyzed. In order to improve the overall operating performance, the use of a variable-Capacity Compressor has been proposed.
S K Chou - One of the best experts on this subject based on the ideXlab platform.
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the performance of a solar assisted heat pump water heating system
Applied Thermal Engineering, 2001Co-Authors: M N A Hawlader, S K Chou, M Z UllahAbstract:Analytical and experimental studies were performed on a solar assisted heat pump water heating system, where unglazed, flat plate solar collectors acted as an evaporator for the refrigerant R-134a. The system was designed and fabricated locally, and operated under meteorological conditions of Singapore. The results obtained from simulation are used for the optimum design of the system and enable determination of Compressor work, solar fraction and auxiliary energy required for a particular application. To ensure proper matching between the collector/evaporator load and Compressor Capacity, a variable speed Compressor was used. Due to high ambient temperature in Singapore, evaporator can be operated at a higher temperature, without exceeding the desired design pressure limit of the Compressor, resulting in an improved thermal performance of the system. Results show that, when water temperature in the condenser tank increases with time, the condensing temperature, also, increases, and the corresponding COP and collector efficiency values decline. Average values of COP ranged from about 4 to 9 and solar collector efficiency was found to vary between 40% and 75% for water temperatures in the condenser tank varying between 30°C and 50°C. A simulation model has been developed to analyse the thermal performance of the system. A series of numerical experiments have been performed to identify important variables. These results are compared with experimental values and a good agreement between predicted and experimental results has been found. Results indicate that the performance of the system is influenced significantly by collector area, speed of the Compressor, and solar irradiation. An economic analysis indicates a minimum payback period of about two years for the system.