Volume 13: Low Carbon Cities and Urban Energy Systems: Part II

Performance comparison of different emissive layers in a combined photovoltaic-thermal and radiative cooling system Salman Ahmed, Tao Ma

Abstract

Recent research suggests that the integration of radiative cooling (RC) technology in photovoltaic-thermal (PVT) systems, can improve the overall system efficiency during the day and provide additional cooling at night. Considering the potential benefits of such a combined system, this study measured the improvements that are achieved in a PVT system performance when using an ideally emissive top layer, and compared them to those achieved with regular glass encapsulation. Results showed that enhanced RC in a PVT system reduced the solar cell operating temperature by most 2 °C and increased total exergy efficiency by 0.65% during the day, and also provided an additional 4-8 W/m2 cooling power at night. Although improvements were achieved in the system performance, it was found that when considering realistic atmospheric conditions and spectral properties, an enhancement in RC does not substantially improve the PVT system performance.

Keywords Radiative cooling, Solar energy, Photovoltaic thermal, PVT, Exergy efficiency, Spectral emissivity