A novel two-step optimization approach for film water cooling of a photovoltaic module in real ambient conditions

Abstract

Efficiency of photovoltaic (PV) modules decreases as they get warmer in real working conditions. One way to address this issue is to apply water-film cooling on the front surface of a PV module. In order to circulate water over the surface of a module, a power-consuming pumping system is required. This paper presents a novel two-step optimization algorithm for improving the water-film cooling system to maximize the net energy generation of a photovoltaic (PV) panel. In the first step, the fluctuations of the optimal water flow rate during a specified day are calculated and then ideal water flow rates on daily and monthly basis are determined. Since the value of the optimum specific water flow rate is a nonlinear function of ambient conditions, it was calculated through an iterative algorithm. In the second step, the appropriate activation time interval for a water-cooling system was determined to furthermore maximize power gain and minimize energy consumption. By optimizing both water flow rate and cooling system timing, a significant improvement in net efficiency was achieved, increasing from 13.98%, 13.85%, and 13.87% in June, July, and August to 14.82%, 14.86%, and 14.80% in Shiraz, Iran.