Solar efficiency index of building envelopes and load matching in low energy buildings

Abstract

Net-zero energy buildings oftentimes rely on solar-based building integrated technologies to offset energy use and achieve their goals. However, the value of a particular system is difficult to assess given that these technologies often bring about complex interactions with the indoor environment, and building energy management systems. The approach chosen in this study was to propose and test a simple index called the Solar Efficiency index (SE index), which makes it possible to characterize the performance of building envelopes with integrated solar systems. The index was used to investigate the effect of different configurations of a PV integrated shading device on an office building in Norway. The results provided by the index allowed estimating how much solar energy was converted and how useful that energy was to the building in terms of load matching. This provided a picture of the building’s energy autonomy.