Experimental and theoretical evaluation of bifacial photovoltaic thermal collectors

This paper represents the theoretical and experimental performances of solar collector using an array of a single pass - air photovoltaic (PV) cells; replacing a diffuse reflector under a bifacial PV module (with an acceptable distance) instead of conventional absorber plate of photovoltaic-thermal (PVT) collectors. Energy and exergy analysis of the solar collector is done by mathematical modeling in one-dimensional steady state condition (1D-SS). A collector rack was designed and fabricated to examine and verify the theoretical model. The steady state exergy efficiency of 4.2 - 10% and energy efficiency 17 - 62% detected for both 0.04 - 0.13 kg/s and 0.22, 0.33, 0.50 and 0.67 of airflow rate and packing factor respectively. The prevailing output of the collector is thermal energy while electricity is the dominant output of exergy. In the range of 0.04 - 013 kg/s, airflow rate has no influence on the overall exergy of the collectors due to the strong dependency of the total exergy on electrical output rather than thermal one. Finally, as the result of increasing airflow rate, the overall output energy of the collector increases due to the increase of the thermal energy harvest.