Investigation on spray schemes for dry-wet hybrid cooling of photovoltaic modules

This study is to investigate the optimal spray cooling scheme for a new dry-wet hybrid cooling system of photovoltaic (PV) module installed with fins at the PV backplane. Three-dimensional models of the PV systems cooled by different spray schemes are developed, and twenty-four spray schemes including one scheme of spray turned on throughout the process, one scheme of spray turned off throughout the process, four schemes of different spray activation times and eighteen intermittent spray schemes are extensively investigated. Results show that: (1) the scheme of spray turned on throughout the process reduces the PV average temperature from 57.93 °C to 42.46 °C, increases the conversion efficiency from 17.62% to 18.29% and increases the net power generation from 228.913 Wh to 233.001 Wh with 880 kg water consumption for 8000 s periods when compared with the scheme of spray turned off throughout the process; (2) the scheme of spray 500 s-intermittent 500 s-spray 500 s is found to be promising as it reduces the PV average temperature with relatively low water consumption and low energy consumption by the water spray system, providing net power generation of 353.347 Wh for 12000 s period and energy efficiency of 1.10 and water efficiency of 2.24 × 10−5, with 1.1%, 223.5%, 224.6% improvement in net power generation, energy efficiency and water efficiency, respectively when compared with the continuous spray.