Thermal aspects of building integrated PV systems

It is well known that photovoltaic device performance declines with elevated temperature, and that building integration will tend to increase the operating temperature, even when installed in cooler maritime climates such as the UK. At worst the elevated module temperatures experienced when building integrated, can cause physical damage to the modules. This paper will explore two contrasting approaches to building integration. The first is a vertical actively ventilated PV facade in which preheating of the building ventilation air is an intrinsic part of the building concept. In this case the PV modules form the semi-transparent outer skin of the double facade, which itself is not thermally isolated from the building interior. The second concerns a PV roof with a modest amount of natural back convection. The roof is well insulated with regard to the building. In both cases, appropriate numerical models have been developed and validated.