Energy Performance of Four Prototypes of PVT Collectors. A Comparative Study.

This work focuses on the energy evaluation of different liquid-based PVT collectors, with the view to obtain a PVT collector able to operate at high temperatures (above 50ºC) with acceptable thermal efficiency. To that end, the use of semi-transparent PV laminates is explored. Four prototypes were developed, tested and evaluated in controlled environment: two models with conventional silicon photovoltaic laminate and two models using a semitransparent photovoltaic laminate. Results show that the glazed PVT with frontal cover models offer better overall energy performance for STC conditions and maintain acceptable thermal efficiencies (30% and 45% depending on the PV laminate) when working at temperatures above 50ºC. Prototypes without frontal cover show good thermal efficiency at STC but present a strong dependency with the operational temperature and wind velocity. Semi-transparent PV laminate remains as an interesting possibility when the PVT collector must operate at high temperature but the electricity production is reduced, still needs to improve the ratio between electricity and thermal energy.