Finite element thermal analysis of a solar photovoltaic module

Abstract

The photovoltaic (PV) efficiency of solar cells is inversely proportional to their operating temperature. The temperature distribution in a PV module will also give rise to thermal stresses within the module. Hence it is important to determine the operating temperature of solar cells accurately. This paper describes the finite element thermal analysis of a typical PV module whereby the temperature distribution in each of the layers of the module is determined. The layers consist of a top glass cover, solar cells and bus bars, ethylvinylacetate (EVA) and Tedlar backsheet. To simulate the actual situation, the frame of the PV module is also modelled. Optical parameters for the reflectivity, transmissivity and absorptivity for the relevant layers are taken into account to determine the actual heat dissipation in the areas exposed directly to sunlight. Heat losses by convection and radiation are also included in the simulation. Temperature contour plots show that there is a temperature gradient across each layer, with the regions near the frame being significantly cooler. The temperature distribution across the cells in the centre of the module is found to be quite uniform, but that for the cells nearest to the frame encounters a 5 °C difference across each cell. The temperatures of the different layers are also compared and it is found that the difference is not more than 1 °C across the thickness of the PV module. As convection heat loss can be highly variable during operation, the effect of varying values of the convective heat loss coefficients at the surfaces of the module is also determined. This analysis provides an understanding of how the convection heat loss coefficient at the module surfaces affect the temperature of the solar cells and their efficiency. © 2011 Published by Elsevier Ltd.