Experiment Study And Numerical Simulation On Falling Film Cooling Solar Cells In Medium And High Concentrating Photovoltaic System

Concentrating photovoltaic(CPV)technologyis becoming a focus in the field of solar power with its less battery area and high photoelectric conversion efficiency.But the current CPV system,especially the high concentrating photovoltaic(HCPV)system with the traditional cooling methods almost exist the insufficient heat dissipation to cause the uneven distribution of temperature or too high temperature of the cell module and to decrease the output power.Therefore,this article considers adopting the direct falling film cooling technology to intensify the heat dissipation of cell components in CPV system,thus improve the efficiency of the system.In order to decrease the experimental complexity and cost,an electric heating plate(EHP)was designed to simulate the dense-array solar cells worked in CPV system.The equivalent concentration ratio is calculated by input power of EHP and the power generation efficiency of triple-junction solar cells.In this paper,experimental and numerical simulation works on heat transfer performance for medium and high liquid-immersion CPV systems were investigated.The experimental results showed that the average temperature of simulated solar cells was controlled well below 60 °C under water temperature of 30 °C and flow rate of 300L/h when concentration ratio ranged between 30 X and 100 X.The maximum temperature difference amongthermocouple measurement points was less than 10 °C,which showed the temperature distribution was well uniform.The average temperature of simulated solar cells was controlled well below 80 °C under water temperature of 30 °C and flow rate of 300L/h when concentration ratio ranged between 300 X and 600 X.The maximum temperature difference among temperature measurement points was less than 10 °C.The numerical simulation results showed that the equivalent concentration ratio has an effect on temperature distribution of EHP.The temperature of EHP maintain at 100 °C when the equivalent concentration ratio is 257.For the lower average temperature and maximum temperature difference of EHP,the larger water flow rate is beneficial when the equivalent concentration ratio is lower;while the smaller water flow rate is beneficial when the equivalent concentration ratio is higher.Allthings considered,falling film cooling systems have an good results when water inlet temperature is 50 °C.At the same water inlet velocity,the different width of the liquid film inlethas little effect on the temperature distribution of EHP.Falling film cooling systems achieve good resultswith the width of liquid film inletof 0.75 mm,water temperature of 30 °C and flow rate of100-150L/h.The inlet water flow rate is no less than 50L/h when width of the liquid film inlet is 1mm.