Performance analysis of double-flow double-exposure solar air heater

Abstract

This work analytically investigates the thermal and thermohydraulic performances of double-flow double- and single-exposure solar air heaters with corrugated and flat plate absorbers. In the double-exposure solar collector, a reflector is placed below and parallel to the collector and reflects the solar radiation on the lower absorber surface. The performances of the collectors with different parameters, such as mass flow rate and insolation, are analyzed. The results of the single exposure collectors are compared with the experimental results to assess the accuracy of the present mathematical model and found to be reasonably well. The performances of the double-exposure collectors are significantly better than those of the single-exposure collectors. Moreover, the performance of the corrugated absorber solar air collector is superior to that of the flat plate solar air collector. The double-exposure corrugated absorber solar air heater is 10.85 % more efficient than the single-exposure flat plate solar air heater at a mass flow rate of 0.0277 kg/s.