Research On Concentrating Photovoltaic/Thermal System Combined With Heat Pump

Heat pump is widely used as an efficient and energy-saving heating device,which is combined with low-concentration solar energy PV/T integrated technology,called solar energy heat pump.When necessary,the heat pump is used as the auxiliary heat source of solar energy or instead of heat source,which can make up for the deficiency of the single solar cogeneration system,and has a very broad application prospect.This paper is based on the low concentration PV/T components and water source heat pump,in order to improve the water temperature and the photovoltaic electrical efficiency,considering the influence of different environmental conditions on the thermal efficiency and electrical efficiency,cop,a kind of low concentration PV/T solar energy heat pump system was proposed,which had carried on the theoretical and experimental research.Details are as follows:1)According to the solar radiation theory,a mathematical model which can simulate the solar radiation of every day when cloudless was established and the curve was dipicted,then compared with the actual value.With the aid of LightTools software,the uniformity of the light distribution on the receiving surface is simulated.A WD-CPC concentrator with higher uniformity of light distribution is designed to improve the photoelectric efficiency.The concentration ratio is 4,and the non-uniformity of WD-CPC is 0.285.2)A kind of C-PV/T component was designed,and the related performance parameters was tested.The test data included PV/T components import and export water temperature,flow rate,power generation,total radiation of receiving surface and other relevant data,the thermal efficiency and power efficiency was calculated.The average electrical efficiency of the low concentration PV/T component during daytime was 10%;and the average thermal efficiency during daytime of the low concentration PV/T components is 40%.3)A theoretical model of the C-PV/T system is established,and the parameters of each part in the system are set up.The evaluation index of the system performance is set up too.Finally,the performance of the PV/T collector during the daytime(28200s～61800s)was simulated,the simulation results show that:in the city of Beijing,Changping District(116.23 degrees north latitude,longitude 40.22 degrees),this system can supply the whole day heating demand of the users with 275.225m2 area,and can produce the electric power which is 54.366kW h.4)Through the experiment,variable conditions on properties of heat pump system was studied.The relation between the heat pump heating power Qc,cooling power Qe and the actual water temperature at the outlet of PV/T modules Tpoto,water temperature of the end of user’s heating system Tno.Then the curve was fitted.The correctness of the numerical relation was verified by experiments.Then the feasibility without the exporting water tank TA2(Tsi=Tpo)is discussed.The whole day temperature variation curve of water tank TAi and water tank TA4 in two cases was obtained.