STUDIES ON SEMI-CYLINDRICAL SOLAR TUNNEL DRYERS - ESTIMATION OF SOLARIRRADIANCE

This is the first part of a set of two papers, about the estimation of solar irradiance on the absorber plate and cover of a semi-cylindrica l solar tunnel dryer (STD). The second part discusses the modelling an d thermal performance results of the STD. A detailed analysis has been carried out in this paper for solar irradiance estimation for the gen eral orientation of the STD with respect to reference positions (N-S, E-W). The obtained values of solar irradiance for the absorber plate a nd cover includes the internal reflection effect up to second-order. I t is found that if the STD axis is in the E-W, the absorber plate rece ives more solar radiation as compared to the other reference position N-S. The amount of solar irradiation absorbed by the cover is also cal culated and found very small compared to the absorber. All calculation s have been made for Delhi climate (28.58 degrees N latitude). (C) 199 8 Elsevier Science Ltd. All rights reserved.