Experimental Study Of Separate Heat Pipe Heat Exchanger Liquid Immersion In CPV Linear System

Solar power technology has been one of the fastest growing,the most dynamic areas of research in recent years,with the increasingly prominent energy issues.The higher photoelectric conversion efficiency and smaller cell area in concentrating photovoltaic system(CPV)than the flat-panel system,would reduce the cost of photovoltaic systems.The cooling problem of the CPV cells not only has a great significance in the battery conversion efficiency and performance,but plays a key link for the stable operation of CPV system.In order to solve this problem,the concept of liquid immersion CPV has been put forward for the first time by the Green Energy Laboratory of Tianjin University in recent few years.Solar cells are directly immersed in some dielectric liquid to lower the cell temperature,and a lot of work have been done in ANU University and UNLV University.The immersion liquid was cooled by the secondary tube heat exchanger in the UNLV.In this paper,a separate type heat pipe heat exchanger is used as a secondary heat sink to cool the immersion liquid,and the heat is removed in a timely manner with heat transfer characteristics of heat pipe.A new structure of separate type heat pipe heat exchanger have been designed and compared with the tube heat exchanger and air condenser,according to the existing small liquid immersion CPV system.From the theoretical analysis and the comparison of various advantages and shortcomings,the heat pipe heat exchanger was thought as the optimal heat exchanger.The heat transfer performance of the separate type heat pipe heat exchanger was researched in the simulate heat source and the actual conditions.Experimental results show that:the heat pipe exchanger had a fast startup,in the condition of irradiance 700W/m~2,the fluid-filled rate of heat pipe is 59%,the air volume is 1847m3/h,the flow of dimethyl silicone oil is 1.812m3/h,the temperature of silicone oil can reach 47?,and the maximum temperature of battery is 53?.The heat dissipation of the heat pipe sink accounted for 87.3%of the total energy;when the fan was shut down,the maximum temperature of dimethyl silicon oil continued to52?,and the maximum temperature of concentrator silicon solar cell was 56?.The rest heat of immersion CPV system can be removed through the separate heat pipe heat exchanger and ensure the concentrator solar cells work in an ideal temperature.