Study on the effects of acetone and R141b on the performance of micro heat pipe PV/T system

Photovoltaic/thermal (PV/T) system could convert solar energy to high-grade electrical and thermal energy, which has significant application value in various aspects such as energy, environment, lifestyle, and economy. The new-developed micro heat pipe PV/T(MHP-PV/T) has excellent potential for combined heat and power generation in cold regions. To elevate the combined thermoelectric performance of MHP-PV/T through heat transfer enhancement ulteriorly, it is of great necessity to research the impacts of working fluids on the performance of MHP-PV/T systems. Two sets of MHP-PV/T systems were constructed, using R141b and Acetone micro heat pipes. We compared their comprehensive performance in terms of electrical and thermal properties using a combination of theoretical and experimental analysis. The performances of two sets of MHP-PV/T systems were compared when the panel inclination angle was 35°, 40°, 45°, and 50° and flow rates of circulating water pump were 5.6 L/min and 7.6 L/min respectively. The results show that R141b MHP-PV/T systems showed higher performances than the acetone MHP-PV/T under all working conditions. When the panel inclination angle is 45°, average thermal power, average electrical power, average thermal efficiency, and average electrical efficiency of R141b MHP-PV/T were 341.8W, 125.8W, 34.1 %, and 12.0 % respectively, which is 58.5W, 50.0 W, 6.8 % and 4.4 % higher than that of acetone MHP-PV/T respectively. In summary, the performance differences of working fluids were systematically compared between acetone and R141b in MHP-PV/T and the results are of great significance to the future application of PV/T in cold regions.