Calculation of the transmittance-absorptance product for flat-plate collectors with convection suppression devices

The effective transmittance-absorptance product ( tau alpha ) is an important parameter in flat-plate solar collectors. The monthly average transmittance-absorptance product ( tau alpha ) sub(m) is frequently required in solar system design methods for calculating the total energy delivered by solar collectors over a design month. A method for calculating ( tau alpha ) sub(m) for plain cover flat-plate solar collectors has been presented by Klein. It is suggested here that this procedure can also be used to calculate the yearly transmittance-absorptance product ( tau alpha ) sub(y).