Phase-Change Material Design for Thermoelectric Generator-Assisted Building Integrated Photovoltaic

Abstract

As the coronavirus pandemic has brought about global economic recession and reduction in greenhouse gas emissions, energy efficient building retrofitting has become a comprehensive solution to increase the employment rate and reduce the energy consumption of buildings. This situation requires more energy-efficient integrated generation systems. In this study, an integrated generation system is proposed for building integrated photovoltaic, thermoelectric generator, and phase change material as an enhanced generation system for buildings. In the proposed system, the phase change material absorbs solar radiation as latent heat within the melting temperature, increasing the photovoltaic conversion efficiency. Additionally, the thermoelectric generator harvests additional electricity as the temperature difference is maintained during the phase change. The total generated energy of the proposed system highly depends on the melting temperature and thickness of the phase change material. Therefore, the appropriate melting temperature and thickness design conditions of the phase change material were derived with the following simulations based on transient energy balance equations in 12 daily profiles. As a result, the optimal melting temperature increased by 5.4°F (3.6°C) and 1.9°F (1.04°C) with an insolation increase of 317 Btu/ft2 (1000 Wh/m2) and a 1.8°F (1°C) increase in ambient temperature, respectively. In addition, the optimal thickness increased by 0.04 in (2.5 mm) with an insolation increase of 317 Btu/ft2 (1000 Wh/m2).