Performance Improvement Optimisation of a Photovoltaic System located at the Tropical Climate using Water-Film Cooling Method

<jats:title>Abstract</jats:title>
<jats:p>The temperature rise of solar panels can cause significant reduction in the energy generation especially for the countries located in tropical climate region. It is more effective to use water-film for cooling the front surface of solar panels, but the energy consumption of the water-cooled photovoltaic system (WCPV) needs to be reduced to obtain a higher net energy gain. In this study, a discrete water-supply water-cooling system (D-WCPV) has been proposed to reduce the energy consumption of the water pump and to improve the performance of a retrofit or building integrated photovoltaic system through reduction of the panel temperature. The discrete mechanism utilises a relay to switch on the power supply of the water pump whenever the temperature of the solar panel has reached the threshold of 45 °C. It is found that minimum flow rate for the D-WCPV is 8 L/min to form a full coverage of water on the surface of the solar panel for providing an uniform cooling effect and hence providing a better performance improvement. A comparison has also been made for the continuous water-supply water-cooling system (C-WCPV) and D-WCPV. D-WCPV has two advantages over C-WCPV as follows: 1) the energy consumption of the water pump operating at flow rate of 8 L/min has been reduced by 86.7% from 0.057 kWh/h to 0.0076 kWh/h and (2) the net energy gain (NEG) of the system at solar irradiation ranging from 806 Wh/m<jats:sup>2</jats:sup> to 950 Wh/m<jats:sup>2</jats:sup> has been increased by 80.2% from 5.5% to 10.0%.</jats:p>