Performance evaluation of a double pass PV/T solar air heater with and without fins

A photovoltaic/thermal (PV/T) solar air heater with a double pass configuration and vertical fins in the lower channel is investigated. The fins are arranged perpendicular to the direction of air flow to enhance the heat transfer rate and efficiency. Air enters the upper channel of the air heater and subsequently flows to the lower channel in the opposite direction. A comprehensive steady state analysis is performed, including energy balances for the upper glass cover, the superstrate of the photovoltaic module, the absorber surface, the back plate and the air in upper and lower columns. The effects of design, climatic and operating parameters are evaluated on outlet air temperature, cell temperature, thermal (energy) efficiency, electrical efficiency and total equivalent thermal efficiency. Thermal performance characteristic curves are also developed for the PV/T collector. The effects of the presence of fins in the lower air channel, the depth of ducts of the air channels, flow rate, inlet air temperature and packing factor are evaluated on the thermal and electrical efficiencies. The extended fin area reduces the cell temperature considerably, from 82 °C to 66 °C. Impact assessments on thermal and electrical outputs of the packing factor are reported, recognizing that higher packing factors are beneficial as they lead to the production of more electrical output per unit collector area and help in controlling the cell temperature.