Evaporative Photovoltaic Cooling - A Comparison of Hydraulic and Air Atomizing Nozzles in Laboratory and Field Measurements

Abstract

Solar radiation allows the operation of photovoltaic modules, but concurrently limits the maximum power output achievable in real operation due to increasing cell temperatures. In this work, experiments are conducted to validate the functionality of an evaporative cooling system for photovoltaics by comparing the results of a custom-made mobile photovoltaic test rig with Pt100 sensors embedded into the solar cell laminate under Western European summer conditions and of a laboratory panel heater test rig. Additionally, results of an air atomizing nozzle installed in the cooling system are presented and compared to hydraulic atomizing nozzles. The cell temperature drops by a maximum of 29.3 °C with a consumption of 6.3 lh∙m2 water and 8800 lh∙m2 compressed air. Dependent on the solar cell type, the electrical efficiency increases by 8.8% – 14.5%. The comparison shows that the air atomizing nozzle yields superior results but is not cost-efficient in the application due to the cost of compressed air.