Effect of PCM thickness on the performance of the finned PV/PCM system

Abstract

The electrical and thermal efficiency of photovoltaic (PV) panels depends mainly on the operating temperature, which is a major problem for this technology. For this reason, various studies have been developed to cool PV panels and consequently improve their efficiency. The use of phase change materials (PCMs) for cooling has attracted the attention of several researchers. This method consists of absorbing thermal energy in the form of latent heat by the PCM and thus decreasing the PV cell temperature. This paper investigates the temperature change of PCM, its liquid fraction, and the thermal behavior of a photovoltaic panel with and without a cooling system. This system is composed of an aluminum heat sink attached with fins and a layer of RT42 Paraffin-type PCM, placed on the backside of the photovoltaic panel. The present research focuses on the effect of PCM thickness on PV panel performance by comparing six different PCM thicknesses: 0.02 m, 0.03 m, 0.04 m, 0.05 m, 0.06 m, and 0.07 m, through a simulation using ANSYS fluent software. In order to make the study more realistic, a meteorological file of Oujda city (eastern Morocco) has been developed and added to the software using a UDF subroutine written in C++, the equations given have integrated the evolution of the ambient temperature and solar radiation as a function of time. The results show that integrating the PCM and fins to the PV panel decreases the PV cells temperature by 32 K compared to the conventional module. This temperature drop is due to the heat stored by the PCM, along with the use of fins that accelerated the heating and melting of PCM. Moreover, it was found that increasing its thickness further decreases the PV temperature. The thickness e = 0.06 m is selected as the most appropriate thickness for the best performance. Lower thicknesses melt quickly under the day sunlight and higher thicknesses do not reach full melting.