Performance and cost analysis of double flow solar air heaters

This study involves a model to investigate the effect of mass flow, channel depth and collector length on the thermal performance and cost benefit ratio for solar collector in double flow mode with and without porous media by using a developed internet based expert system. The thermal performance was determined over a wide range of operating conditions, and the optimum operating conditions were determined. It is found that for drying purpose the designed air flow rate should be in the range of 0.03 to 0.04 kg/s, and the thermal efficiency increased by 5% in double flow after using porous media. On the other hand it is concluded that the higher in cost energy for any particular combination of flow depth, collector length and mass flow rate is at short collector length, small flow depth with high quantity of mass flow rate. Moreover, the values of duct lengths and depths for which the cost of solar energy is minimized are different for different values of mass flow rates.