OPV-PCM-ETFE foils in use for public buildings: electrical performance and thermal characteristics

Abstract

ETFE (ethylene tetrafluoroethylene) foil integrated organic photovoltaic cells (OPV) is a promising new building material that can convert solar energy into electricity and thus facilitate the aim of carbon neutrality. The electricity generation is significantly influenced by the high temperature coexisting in the composite OPV-ETFE foils. Using phase change materials (PCM) to regulate thermal effects can improve energy conversion and achieve better building thermal performance. The lack of the relationship between ETFE layer, OPV layer and PCM layer is the main reason that limits the understanding of how to utilize such materials for designing new public buildings. This paper thus investigates the basic performance of the OPV-PCM-ETFE foils, with a special emphasis on the dynamic temperature characteristics and the enhanced electrical performance. The new material composed of an OPV layer, a PCM (RT-28HC) layer and an ETFE layer from the top to the bottom is developed and characterized. The experimental results show that a significant temperature difference between specimen surface and rear face demonstrates the excellent performance of temperature regulation and that the open-circuit voltage keeps at a relative stable value due to the PCMs. Furthermore, the comparison analysis validates that the thermal performance of the OPV-PCM-ETFE foils is dependent on the solar irradiance and the PCM amount. In addition, the distribution of the PCM and the incorporation of the air cavity play a role in the temperature distribution. Generally, these properties provide the crucial insights into the evaluation of electrical and thermal performance of the OPV-PCM-ETFE foils.