Effect of number of glass covers on performance of flat- and corrugated-plate solar air heaters

A theoretical study of the performance of flat- and corrugated-plate solar air heaters (SAHs) is conducted. This study focuses on the effect of the number of glass covers on SAHs behavior. The isotropic diffuse model is utilized to calculate the effective transmittance-absorptance product, while the energy balance equation is employed to estimate the thermal efficiency. The hourly and monthly meteorological data for Amman, Jordan is adopted to generate the results. Increasing the number of glass covers has a positive effect represented by decreasing the overall heat loss coefficient and a negative influence characterized by decreasing the effective transmittance-absorptance product. These opposite effects result in an optimal number of glass covers that achieves the highest heater performance. Based on the model in this work and operational conditions for Amman, the optimal number for glass covers is two.