Performance Analysis of Uncovered PV-T Collectors for Radiative Cooling and Heating Applications

Abstract

New uncovered photovoltaic-thermal (PV-T) collectors were developed and tested to produce electricity, chilled and hot water. The use of uncovered PV-T collectors has already been investigated for heating applications. However uncovered PV-T collectors are also interesting for radiative cooling applications. This concept was already demonstrated in two plus energy houses that participated in the Solar Decathlon Europe competition. The working principle of radiative cooling is to use the radiative heat loss of the collector top surface to cool down a fluid which is then used to air-condition a building This paper focuses on the collector design characteristics and their performances for radiative cooling and heating applications. The procedure for the performance characterization is inspired from the quasi dynamic test method for uncovered thermal collector of the new EN ISO 9806:2014. For the identification of the collector parameters GenOpt has been coupled with TRNSYS. These coefficients are then used to establish the thermal efficiency curves for heating and cooling applications: the results of three different PV-T collector designs are compared between each other and to the performance of an uncovered solar collector.

Applications of radiative sky cooling in solar energy systems: Progress, challenges, and prospects

“…Compared to very few studies that employed air as the working medium of the PV-PT-RC system, much more works paid attention to the water-based PV-PT-RC system given that water, as the thermal carrier, shows better heat transfer performance [148][149][150][151][152][153][154][155][156][157][158][159][160][161][162][163]. However, the water temperature at the outlet of the PV-PT-RC collector in an opened system can hardly be heated up or cooled down to effective levels due to its large thermal capacity.…”