cooling of photovoltaic panel equipped with single circular heat pipe: an experimental study

The cooling process of photovoltaic (pv) panel is one the main issues in the field of solar systems. the temperature of solar cells increases when the solar radiation and also the ambient temperature increase. increasing the cell temperature reduces the electrical output power of the panels as well as their lifetime. in order to solve this problem, various methods have been provided for cooling the panels. one of these methods is the application of heat pipes. in this research work, a pv panel equipped with thermosyphon heat pipe is introduced. the thermosyphon is connected to the back sheet of the panel in order to enhance the cooling effect of the pv system. instead of using the polyvinyl fluoride polymer, unlike the conventional panels, an aluminum plate is used to connect the heat pipe to the back of the panel to have a better cooling. in addition, in order to increase the heat transfer area between heat pipe and the back surface of the panel, a special groove is drilled on the aluminum plate. three different filling ratios (25%, 45%, and 65%) of distilled water, as the working fluid, are used in thermosyphon. the best performance of the systems is obtained at 45% of filling ratio, in which the electrical power of the pv panel equipped with heat pipe is around 3.2% better than the conventional pv panel. in this case, a 6.8 °c temperature difference is observed in the water tank connected to the condenser section of heat pipe, which means that 54 kj heat is transferred to the water in the tank.