Energy balances for upward-type baffled solar air heaters

Considerable improvement in the collector efficiency of solar air heaters is obtained if the fins in the collector have attached baffles to create air turbulence and an extended heattransfer area. Further improvement in performance can be achieved if the fins with baffles are attached over the absorbing plate in such a manner that air flows over, instead of under, the absorbing plate and creates free convection. In this paper, energy balances for upward-type baffled solar air heaters have been developed and a theoretical equation for estimating the collector efficiency has been derived.