A preliminary computational study of flat roof convective thermal resistance in the presence of photovoltaic panels

Abstract

The effect of roof mounted photovoltaics on the heat transfer performance of roofs has primarily been investigated in the context of the resulting shading effect. The convective heat transfer coefficient will change as a result of the blockage caused by the photovoltaic panels. In this work, a quantification is given of the differences between heat transfer coefficients on a bare roof and a roof with photovoltaic panels having a specified configuration. A computational fluid dynamics approach is used. The study is only preliminary and hence a standard k-e turbulence model is used. The presence of photovoltaics is found to increase the convective heat transfer coefficients by around 26% for a north wind. The influence on the U-Value depends on the type of roof construction but for summer conditions an increase in U-value is observed which has positive cooling effects.