Fabrication and Performance Evaluation of a Directly Immersed Photovoltaic-Thermal Concentrator for Building Integration

Abstract

A novel concentrating photovoltaic-thermal solar collector was designed, fabricated and experimentally investigated at the University of Lleida, in Spain. Two designs based on two dielectric liquids, isopropyl alcohol (IPA) and deionised water (DIW), were developed. In both cases, the solar cells were directly liquid-immersed. The study includes experiments and numerical simulations. The proposed concentrator was incorporated into a testing unit to examine its potential as a façade by controlling light and thermal flux transmitted into a building. The results show promising electrical performance and acceptable thermal performance, with thermal losses ranging from 14 to 20 W °C−1m−2. The optical efficiency was around 73% in the case of the concentrator with DIW and about 76% for the one with IPA. Regarding electrical performance, the fill factors for IPA and DIW configurations are as follows: 62.8% and 61.7%, respectively. The comparison results reveal striking differences between the testing unit with and without solar concentrators, with the concentrator-equipped unit showing around four times lower illuminance and a 50% reduction in maximum heat fluxes and interior temperature. Generally speaking, it can be said that these energy-generating façades show satisfactory behaviour and offer interesting possibilities for building-integrated applications.