Experimental Study Of A Photovoltaic Solar-assisted Loop Heat Pipe/Heat Pump System

At present, with the traditional energy exhausting and the increasingly serious environment problems, solar energy as a kind of clean renewable energy is increasingly concerned by people, and the study of solar energy resources utilization has gained widely application. The use of solar energy resource mainly include photo-thermal technology, photovoltaic technology and hybrid photovoltaic/thermal technology (PVT). The PVT technology can produce two kinds of profits of electricity and thermal energy, which can improve the comprehensive utilization of solar energy.The loop pipe is a good kind of heat transfer device, which can realize the long distance transmission of heat with phase change of the heat pipe working medium. Many advantages could be acquired by combing the loop heat pipe with the solar plate collector, such as realizing long-distance transmission of heat, reducing heat loss with the loop heat pipe heat diode characteristics in the condition of weak irradiation intensity or zero irradiation in the evening, and simple operation without energy consumption.The heat pump is a high efficiency energy transmission equipment, which can achieve heat from low heat source to the high heat transfer. In solar assisted-heat pump (SAHP) system, the plate solar collector acts as the evaporator of heat pump cycle. Therefore, the SAHP system can significantly improve the evaporation temperature, which leads to higher collection efficiency and coefficient of performance (COP).The composite photovoltaic solar-assisted loop heat pipe/heat-pump (PV-SALHP/HP) system has been presented by combining the solar loop heat pipe system with solar assisted heat pump system. The composite system processes the features of loop heat pipe mode and heat pump mode. The two modes share the same evaporator and condenser, which can achieve mutual switch operation and independent operation. The loop heat pipe mode has the features of simple operation without energy consumption, but requires higher solar radiation intensity and environment temperature. Correspondingly, the heat pump mode has less requirement with solar radiation intensity and environment temperature, but needs to consume energy. Thus, the composite system can run different mode according to the advantages of different operation mode, ensuring stable thermal energy supply and reducing energy consumption with rational utilization of energy.Two key points should be included in the article:(1) PV-SALHP/HP system has been constructed in the open air, and instantaneous performance and daily performance have been carried out under loop heat pipe mode and heat pump mode.(2) PV-SALHP/HP system has been constructed in enthalpy difference laboratory, and the performance of different operation mode has been analyzed under different irradiation intensity and environment. Then the reasonable advice has been given from the prospect of meteorological condition, saving energy and running.