Research On Demonstration System Of High Concentrated Photovoltaic Combined Cooling,Heating And Power

The extensive use of fossil energy leads to serious environmental problems.Solar energy,as a safe,rich and environmentally friendly renewable energy,is one of the clean energies with broad development prospects.The concentrator photovoltaicthermal(CPVT)technology can not only provide electric energy through photovoltaic conversion of solar cells,but also recover heat energy through cooling batteries for waste heat utilization.However,there are still some problems in the concentrator photovoltaic-thermal system(CPVT)such as temperature control and system optimization.Aiming at these two problems,this paper studies the high concentrated photovoltaic combined cooling heating and power system.The main contents and conclusions are as follows:A Fresnel high concentrated photovoltaic-thermal module unit was designed and developed.Through the energy flow process of photovoltaic modules,the theoretical model is constructed from the Fresnel lens concentrating process,solar cell photoelectric conversion process and heat transfer process,and the experimental platform of the micro concentrator photovoltaic-thermal system is built to test the theoretical model,and the theoretical and experimental results are in good agreement.At the same time,the performance of the micro concentrator photovoltaic-thermal system is tested,and the influencing factors of the system are analyzed.The experimental results show that: the power generation efficiency of the system is 26.2%,the comprehensive utilization rate of solar energy is 75.4%,and the cooling water flow has a great impact on the system performance.So,it is necessary to formulate different control strategies for the system according to different working conditions.Through the integration of a large number of module units,the demonstration system of a 100 kW high concentrated photovoltaic combined cooling heating and power was built.The system consists of 500 times Fresnel concentrating photovoltaicthermal module,water-cooled waste heat recovery and utilization module,phase change heat storage module and lithium bromide absorption refrigeration module.Electricity power generated by the system is used for charging pile,and the waste heat is recovered for lithium bromide refrigeration unit in summer and heating in winter.The system is tested.the test results show that the power generation of the system can reach 10-15 kw,and the power generation efficiency is more than 26%,and the comprehensive utilization rate of solar energy is more than 75%.The phase change temperature of the phase change regenerator used in the system is 85 ℃,and the temperature difference between endothermic and exothermic is less than 10 ℃,and the heat storage capacity is more than 360 MJ.At the same time,the system uses lithium bromide absorption chiller,and the refrigeration power is above 15 kw,and COP is above 0.75.This is a breakthrough of solar energy CCHP technology from laboratory model to large-scale application.Finally,the theoretical models are constructed from the concentrator photovoltaic module,the concentrator solar thermal module and the waste heat utilization module,and the steady-state operation theoretical model of the system is established through the system cycle connection,and the model solution and optimization method are proposed,and the theoretical model is verified.According to the theoretical model optimization method of demonstration system,the system is optimized and regulated from the normal steady-state operation,power supply demand and waste heat utilization demand.The optimized system performance is greatly improved and the optimization effect is remarkable.This study can be used as a reference for large-scale application of CCHP technology of solar energy from laboratory model.