Performance enhancement of photovoltaic panels using rotating elliptic enclosures filled with phase change material

Deterioration in efficiency caused by elevated temperatures of solar photovoltaic (PV) panels limits their utilization in hot environments and in concentrated irradiance applications. This article proposes cooling PV panels without introducing bulky or costly components. The cooling effect is achieved through a basin attached below the panel. The basin is equipped with elliptic enclosures (EE) containing phase change material (PCM). The EEs are set at a distance below the PV allowing for a small gap. The EEs can rotate around their axes inducing motion that boosts PV cooling. This motion is sought to enhance heat transfer from the hot lower surface of the PV to the fluid and from the fluid to the PCM. The EE also acts as a constant temperature heat sink storing heat rejected by the panel during the day and rejecting this stored heat to the ambient (through water and then through the basin’s lower surface) during the night. The current article discusses the effect of the number of EEs, their distance below the panel surface and their rotational speed on the PV electrical output. System performance is assessed numerically for ambient conditions of Cairo, Egypt at noon of the summer solstice. The best design is identified based on the highest overall efficiency, considering the enhancement in output power due to cooling and the power consumed in overcoming friction between the EEs and the surrounding water. The results were used to generate an optimum case resulting in 13.5% enhancement over an uncooled PV panel.