Passive cooling of photovoltaic panel by aluminum heat sinks and numerical simulation

One of the biggest problems of generating electricity by photovoltaic panels is that about 80% of the incoming solar energy is transformed into heat. The heat causes the rise of operating temperature of the panel, thereby reducing its efficiency and performance characteristics. In this research, photovoltaic panel was passively cooled by means of aluminum heat sinks with different geometries in order to determine the enhancement of output characteristics. Decrease in temperature by an average of 7.5 °C by means of heat sinks lead to increase in open-circuit voltage of 0.27 V, compared to the reference panel. Based on the experimentally obtained results, software was used to simulate the temperature and velocity fields for a string of three heat sinks, thus obtaining a better insight in heat transfer process of heat sinks. A polyhedral mesh and laminar fluid flow were applied for the simulation, leading to a good agreement between the experimentally obtained and simulated temperatures of the heat sinks, with average difference of about 1 °C. In order to determine the most efficient geometry of the heat sink for passive PV cooling applications, the data obtained by the experiment and simulation were numerically analyzed. The second heat sink, with its overall design (contact area with the panel, fin length, fin spacing), more effectively dissipates accumulated thermal energy to the surrounding air compared to the other two heat sinks. A model was developed to simulate the characteristics of a heat sink under various conditions using the laminar fluid regime and air temperature and the base temperature as input parameters. The results of this study can be used to optimize the design of heat sinks and improve their efficiency in cooling PV panels.