Performance analysis of micro heat pipe PV/T within and outside the greenhouse in northwest China

Abstract

The study investigates the performance of a micro heat pipe (MHP) photovoltaic/thermal (PV/T) system operating with R141b as the working fluid under the climatic conditions of Lanzhou, situated in the northwest region of China—a locale noted for its high solar insolation. This study operates the PV/T system in the greenhouse, improving system performance while addressing the issue of wind and sand adhering to the surface of PV/T panels in the northwest region, which affects system performance. Empirical analysis was conducted in summer and winter to ascertain the system's performance. Results indicated that the PCE in winter inside and outside the greenhouse were found to be 7.1% and 13.1%, respectively, while the summer season values were 6.5% and 12.3%, respectively. Notably, the average thermal power generated within the greenhouse during winter was measured at 464.8 W/m2, surpassing the outdoor average thermal power by 61.9 W/m2; similarly, in summer, the internal thermal power was 313.9 W/m2, exceeding the external by 51.7 W/m2. The total efficiency was the highest inside the greenhouse in summer, at 61.5%, while the lowest total efficiency was observed outside the greenhouse in winter, at 34.3%.