Performance and water-energy nexus aspects of stagnant water layer cooled zero-tilt solar photovoltaic module.

This study proposes a novel stagnant water layer cooling concept to enhance performance of solar photovoltaic (PV) modules. Three distinct types of water-seawater (Scenario 1), tap water (Scenario 2), and desalinated water (Scenario 3)-were utilized to cool a 10 WP polycrystalline PV module by establishing a stagnant layer of 1.0 cm thickness over it, under the climatic conditions of Visakhapatnam (17.62°N, 83.21°E), India. The average daily temperature variations between the reference and modified PV modules were approximately 7.0 °C, 7.2 °C, and 8.2 °C for Scenarios 1, 2, and 3, respectively. The daily average electrical efficiency & energy output of the modified PV modules under Scenarios 1, 2, and 3 were approximately 16.2 & 14.9, 18.6 & 16.6, and 30.8 & 28.3%, relatively higher than the reference PV module, respectively. Exergy efficiency, sustainability index and specific CO2 emission of desalinated water-cooled PV module were 7.41%, 1.08, and 406 g/kWh, respectively. However, the desalinated water-cooled PV module exhibited 29.1 and 15.1% higher evaporation losses than those of the seawater and tap water-cooled PV modules, respectively, under similar solar energy of 21.4 MJ/m²d. The proposed cooling technique is effective and economic, depends on the type of utilized water.