Improving the photovoltaic thermal system efficiency with nature-inspired dolphin turbulators from energy and exergy viewpoints

The main purpose of this study is to enhance the efficiency of the photovoltaic thermal (PVT) system using nature-inspired dolphin turbulators designed based on thermal images of the dolphin dorsal fin. The turbulators are placed in the cooling channel of the PVT. The effects of the number and length scale of the turbulators are investigated on electrical, thermal, and overall efficiencies from energy and exergy perspectives, as well as the photovoltaic cell temperature at different times of the day. The dolphin turbulator enhances heat transfer to the coolant by preventing the boundary layer growth, accelerating the fluid flow, directing and impacting the coolant to the absorber plate, and improving the mixing of coolant. Consequently, turbulators reduce the photovoltaic cell temperature, increase the coolant temperature, and improve efficiencies. The enhanced PVT improves the electrical, thermal, and overall efficiencies by about 2.59%, 16.9%, and 14.78% from the energy viewpoint and 2.59%, 12.87%, and 3.77% from the exergy viewpoint compared to the conventional PVT. In addition, this study investigates how operational conditions, such as the coolant Reynolds number, the coolant inlet temperature, and ambient wind speed, affect the efficiencies from energy and exergy viewpoints.