Tilt Angle Optimization and Passive Cooling of Building-Integrated Photovoltaics (BIPVs) for Better Electrical Performance

Abstract

Building-integrated photovoltaic systems (BIPVs) are one of the fastest growing technologies of the renewable energy industry. Numerous attempts are made worldwide for the widespread application of these multifunctional and environmentally friendly systems. A barrier to fulfil this objective is the uncontrolled operating temperatures of BIPVs. The operating temperature of a photovoltaic module or system is a crucial parameter, which has a great influence on the system efficiency and the output energy. For better electrical output from a BIPV, the operating temperature of modules needs to be kept as low as possible. In this respect, tilt angle optimization and cost-effective passive cooling arrangements are investigated within the scope of this paper. In most cases, BIPVs are installed in parallel with the facade; however, the tilt angle impact on module temperature might be significant and hence is investigated for five different values of tilt angle (θ = 0°, 15°, 30°, 45° and 60°). The effects of passive cooling on module temperature of BIPVs are also evaluated for three different fin configurations (rectangular, pin and trapezoidal fin). The paper is based on a CFD methodology. The results are compared with a previously published theoretical work, and an excellent agreement is observed. Five different photovoltaic cell technologies (TF-Si, c-Si, CIGS, CdTe and a-Si) are evaluated in terms of the enhancement in power output. It is observed from the CFD results that the minimum operating temperature of BIPVs is obtained for θ =15°, whereas the maximum temperature is seen at θ = 60°. The results also indicate that more than 5 % enhancement in maximum power output can be obtained for TF-Si-based BIPVs at standard test conditions.