An in-depth study on the annual performance of acetone and R141b micro heat pipe PV/T systems

Photovoltaic/thermal (PV/T) technology has become a research focus in the field of solar energy due to its ability to simultaneously generate electricity and heat, significantly improving the efficiency of solar energy utilization. However, micro heat pipe PV/T modules still face technical bottlenecks such as high operating temperature of solar cells and insufficient heat transfer efficiency to the cooling working fluid. It is urgent to improve the comprehensive performance through enhanced heat transfer technology. This study conducted in-depth research based on different micro heat pipe heat exchange working fluids, combined with experimental tests and theoretical analysis on typical days throughout the year. The average start-up time of acetone on test days in different seasons is 28.2 %, while that of R141b is 86.5 %. In terms of thermal resistance characteristics, the average thermal resistance of R141b micro heat pipes accounts for 7.5 % of the total thermal resistance of the PV/T module, which is significantly lower than the 15.5 % proportion of acetone micro heat pipes. In terms of performance, the average photovoltaic efficiency and average photothermal efficiency of the R141b micro heat pipe PV/T system are 6.8 % and 9.1 % higher than those of the acetone micro heat pipe PV/T system, respectively. This study clarifies the influence mechanism of different working fluids on the performance of micro heat pipe PV/T modules, providing a solid practical basis for the application of micro heat pipe PV/T technology.