Enhanced photovoltaic panel energy by minichannel cooler and natural geothermal system

Abstract

Commercial photovoltaic (PV) solar panels convert the solar energy directly to electricity but their efficiency is low. The rest of the energy is mostly converted to heat. Although the conversion efficiency of PV panels is low, getting hot causes increase in the temperature of the PV cells which results in further dramatic decrease of their efficiency and the technical lifetime. In the present study, a PV panel with cooling system was made in which a polymer minichannel heat exchanger was fully integrated with the PV cells during the fabrication of the panel. Heat exchangers containing minichannels and microchannels have higher heat transfer capability than pipes and channels as they have a higher ratio of area to volume. Besides, since the heat exchanger is adhered to the solar cells during the panel fabrication, the thermal contact resistance drops to minimum. Circulated coolant dissipates the extracted heat from the panel to the ground by buried long life and low-price plastic tubes. Since the earth temperature beyond a depth of 4 m is relatively constant, 10°C to 16°C, the earth acts as a cooling medium for free. The experimental results show that the cooling system is capable to dispose of 570 W heat from the PV panel in the ground. The daily electricity generation rises about 10%. The levelized cost of energy (LCOE) is minimum compared to the available PV panels with active cooling techniques in the literature.