Papers by Keyword: Heat Pump System

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Authors: Hong Bing Chen, Ping Wei
Abstract: Many studies have found that the photovoltaic (PV) cell temperature plays an important impact on the solar-to-electricity conversion efficiency. Different cooling liquids like air and water have been introduced to pass across the PVs to reduce the cell temperature, and thus increase the electrical efficiency. In this paper, the refrigerant R134a is used as the cooling liquid and the PV/thermal (PV/T) panel is coupled with a heat pump system acting as the evaporator, which is expected to achieve a better cooling effect and energy performance due to its low boiling temperature. Two different kinds of PV/T panels, glass vacuum tube (GVT) type and flat plate (FP) type, are proposed for the study on the energy performance comparison. The results show that the GVT PV/T panel has an average thermal efficiency of 0.775 and an average electrical efficiency of 0.089 (based on the reference efficiency of 0.12), which is 73.4% and 1.1% higher than that of the FP PV/T panel respectively, with the solar radiation varying from 200 W/m2 to 1000 W/m2. The GVT PV/T heat pump system has an average COP of 5.6, 9.8% higher the FP PV/T heat pump system. The GVT PV/T heat pump system has a better energy performance than the FP PV/T heat pump system.
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Authors: Hong Bing Chen, Ping Wei
Abstract: The decrease of photovoltaic (PV) cell temperature by 10 °C is expected to improve the PV electrical efficiency by 0.6-0.7% based on the reference efficiency of 15%. Different cooling liquids like air and water have been introduced to pass across the PVs to reduce the cell temperature, and thus increase the electrical efficiency. In this paper, the refrigerant R134a was used as the cooling liquid and a PV/thermal (PV/T) collector was coupled with a heat pump system acting as the evaporator, which was expected to achieve a better cooling effect and energy performance due to its low boiling temperature. A hybrid PV/T collector, made of 6 glass vacuum tube – PV module – aluminum sheet – cooper tube sandwiches connected in series, worked as the evaporator of the heat pump system. Numerical steady models were established for each component of the heat pump system and part of the PV/T collector/evaporator for predicting their energy performance under the weather data of January 14th at Tibet, China. The results showed that the maximum COP could reach up to 7.6. The daily average thermal efficiency and electrical efficiency were 0.764 and 0.104, respectively.
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Authors: Jia Zheng, Yuan Yu, Juan Li, Chang Hong Fu
Abstract: This paper concerns the utilization parameters of reclaimed water, and evaluates the heat resource potential and suitable development area of reclaimed water. The heat energy from reclaimed water resources is expected to reach 1027 MW in 2020. The building area that is suitable for adopting reclaimed water heat pump system is about 1.4×108m2. The potential of utilization and development space are huge. There is more than 30% savings of operating cost by using reclaimed water heat energy for buildings with contrast to traditional supply mode, and can reduce more than 70% of the exhaust heat at the same time. The economic and environmental benefit are great.
728
Authors: Jian Feng Qian
Abstract: Urban sewage is a renewable energy source in the fields of heating and air conditioning engineering, and urban sewage source heat pump system plays an important role on energy-saving and environmental protection. According to the differences of the sewage emission coefficient and heat load of the building, it is not able to satisfy the user heating demand only on the limited temperature difference sensible heat on many situations, especially for the sewage rate of flow in small trunk canals. Therefore, a new heat system named urban sewage source heat pump system with freezing latent heat collection is proposed, in which the freezing latent heat is used as the heating source of the heat pump system at peak heat load in winter as well as the temperature difference sensible heat. According to the status, the system form is brought out and the operation modes of this heat pump system are stated, then the characteristics of the design and operating parameters are discussed.
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