Development of solar radiation spectrum-controlled emulsion filter for a photovoltaic-thermal (PVT) system

Abstract

This paper firstly proposes a de-coupled photovoltaic-thermal (PVT) system with solar radiation spectrum-controlled emulsion filter. This system selectively absorbs and transmits solar irradiance to a photovoltaic (PV) module through a liquid filter placed on top of the PV module, which is named a de-coupled PVT system. The emulsion filter effectively absorbs ultraviolet, visible light, and near-infrared wavelengths, which do not contribute to electricity generation in PV modules, and converts them into thermal energy. Fish oil was selected for thermal energy production. The emulsion filter showed a thermal stability up to 70 °C and lowered the temperature of the PV module from 46.7 °C to 33.1 °C. The performance of the de-coupled PVT system and PVT system were compared to evaluate a total energy efficiency under various conditions. The de-coupled PVT system with emulsion filter recorded the total energy efficiency of 84.4%, showing superiority over the conventional PV system (18.0%), PVT system (70.9%), and de-coupled PVT system (water, 79.3%). When solar irradiance is 1000 W/m2 in summer, the electrical energy and thermal energy produced by the de-coupled PVT system with emulsion filter are 72.2 Wh and 1176.7 Wh per day, respectively. According to the economic analysis, it was concluded that the CPBTs for PVT system, de-coupled PVT system (water) and de-coupled PVT system (emulsion) were 9.93 year, 9.56 year and 8.89 year, respectively.