Hybrid Photovoltaic Thermal (PV/T) Air and Water Based Solar Collectors Suitable for Building Integrated Applications

Abstract

Problem statement: Experiments have been conducted to investigate the effect of mass flow rates on the electrical, thermal and combined of photovoltaic thermal efficiencies of the hybrid collectors. Approach: Two photovoltaic thermal solar collectors were designed and fabricated. The first collector, known as spiral flow absorber collector, designed to generate hot water and electricity. The second collector, known as single pass rectangular tunnel absorber collector designed to generate hot air and electricity. Both absorber collectors were fixed underneath the flat plate single glazing sheet of polycrystalline silicon PV module. Water was used as a heat transfer medium in spiral flow absorber collector and air for the Single pass rectangular tunnel absorber collector respectively. Results: The experiment results showed that the single flow absorber collector generates combined PV/T efficiency of 64%, electrical efficiency of 11% and power maximum achieved at 25.35 W. Moreover, Single pass rectangular tunnel absorber collector generated combined PV/T efficiency of 55%, electrical efficiency of 10% and maximum power of 22.45 W. Conclusion/Recommendations: The best mass flow rate achieved for spiral flow absorber collector is 0.011 kg sec^-1 at surface temperature of 55% and 0.0754 kg sec^-1 at surface temperature of 39°C for single pass rectangular collector absorber. It was recommended for PV/T system to further improve its efficiency by optimizing the contact surfaces between the solar panel (photovoltaic module) and the tubes underneath and also recommended to use other type of photovoltaic cell such as amorphous silicon cell that posses the black mat surfaces property that will improve it thermal absorption.