Assessment of factors affecting the performance of a novel double condenser heat pipe Photovoltaic-thermal (PV/T) system in hot water mode: An experimental study in the lab

One of the advantages of heat pipe Photovoltaic/Thermal (PV/T) technology is to provide electrical power and thermal at the same time. The heat pipe PV/T system uses the gas-liquid density as the working medium to drive the system without any other additional driving force. However, most of the existing heat pipe PV/T technologies have single heat application. In order to expand the application, we proposed a multi-functional heat pipe PV/T system that can realize produce hot water, space heating and simultaneous modes while generate electricity according to the terminal demand. The laboratory tests were conducted to study the effects of solar radiation, type of heat conduction backplane, height difference between evaporation and condensation section, inclination angle of PV/T plate and liquid filling rate of evaporator on the system efficiency under hot water mode. The results show that the total efficiency of the system decreases with the increase of solar radiation, however, the maximum total efficiency of the system was achieved with backplane of larger heat conduction thermal conductivity and larger PV/T plate inclination. The height difference has little effect on system performance while the liquid filling rate has an obvious effect on the temperature uniformity of PV/T panel. The laboratory electrical, thermal and total efficiency of the system could reach 7.2 %, 74.3 % and 80.2 %, respectively under 540.1 W/m2 of solar radiation, 1 mm of aluminium plate, 1.6 m height difference, 45° of PV/T plate inclination and 90 % of the liquid filling rate. This research provides important experimental data for the application and layout of the heat pipe PV/T system.