Modelling and Simulation in Simulink of a Water-Based Automatic Cooling System to Reduce Efficiency Loss due to Heat in Photovoltaic Panels in Ecuador

Abstract

The present project introduces a low energy consumption, low maintenance required, affordable and simple to install water based automatic cooling system modelling and simulation to reduce efficiency loss in photovoltaic panels due to heat. It is focused for residential applications in Ecuador due to the energetic crisis that happened last year and its geographical location that makes it ideal to implement this renewable solution improved by the proposed system. Photovoltaic panels efficiency is low, near 20%, which makes it extremely important to avoid losses. High irradiance in Ecuador causes panels to have maximum efficiency, but at the same time causes them to heat and have thermal loss at a rate of 0.5% per °C above room temperature. The substrate of the panels causes them to reach temperatures around 70°C at maximum irradiance peak values, even having a maximum temperature of 30°C approximately in this country. Low efficiency of the panels requires a low energy consumption solution resulting in avoiding using actuators like pumps, which also increases the system’s maintenance frequency. The system is designed using valves with a time-based algorithm to fill a water tank from regular faucets, cool the panels using gravitational fall while they are cleaned at the same time and the resultant hot water can be reused. Real elements are proposed with an economic analysis to observe the financial viability of the system. Water volume is limited to 4m3 daily, even being low the price of it in this location, to not misuse another resource. However, an analysis is presented too to compute the water volume needed to have no efficiency loss due to heat. In a worst-case scenario of irradiance peak of 1000W/m2, the system provides 6% efficiency improvement, being very significative compared to the efficiency that panels can reach. Finally, a rain detector is included in the system to avoid misuse of water in both filling and cooling processes when it is raining during the irradiance period.