Experimental Thermal and Electrical Characterization of a Novel Spectral Beam Splitting Low-Concentrating Photovoltaic Thermal Collector
Abstract
The effect on the thermal and electrical performance of a low-concentrating photovoltaic-thermal LCPVT collector due to the implementation of a spectral beam splitter SBS and a secondary thermal receiver is experimentally investigated. The SBS was made with a commercial spectral film filter, and it was installed in front of the PV cells of the triangular PVT receiver of the LCPVT that is cooled with water. The SBS has the function of transmitting most of the wavelengths of the solar spectrum that are used for the PV cells to generate electricity reflecting the rest of the spectrum to a secondary thermal absorber where water can be heated to higher temperatures. The total thermal efficiency of the LCPVT with the SBS filter and the secondary thermal absorber was 45%. Electrical efficiency was reduced from 7.3% for the case of LCPVT without SBS filter to 2.7 % for the case of using the SBS filter and secondary thermal receiver. Reduction of efficiency is attributed to optical losses, radiation blockage and the non-optimal response of the spectral film employed. The proposed design of SBS could reduce the surface temperature of the PV cells by 10 °C compared to the case without the filter, and the difference of temperature between the inlet and outlet of the secondary thermal absorber could be increased 13.5 °C by reducing independently the mass flow from the PVT receiver. The technical feasibility of the proposed SBS filter configuration using inexpensive commercial filters was experimentally proved with the potential to generate heat of higher temperature maintaining low temperatures for the PV cells.
Keywords
hybrid photovoltaic thermal, parabolic low-concentrating trough, spectral splitting, PVT, Dichroic filter, secondary thermal receiver