Performance Evaluation of Solar Air Heater Having Chamfered Rib Groove Roughness on Absorber Plate

A parametric study of artificial roughness geometry in the form of chamfered rib groove type on the underside of absorber plate of solar air heater has been carried out and compared with smooth duct. The performance evaluation in terms of energy augmentation ratio (EAR), effective energy augmentation ratio (EEAR) and exergy augmentation ratio (EXAR) has been carried out for various values of roughness parameters of chamfered rib groove roughness for a wide range of temperature rise parameter. It is found that the augmentation ratios increase with temperature rise parameter in the order of EAR, EEAR and EXAR. The artificially roughened solar air heater duct performs better as per EAR or EEAR for any values of temperature rise parameter and roughness parameters. The EAR is high for the parameters of chamfered rib groove type roughness geometry which create more turbulence, however the pump work required for flow of air also increase. The EXAR is a more suitable criterion to incorporate the quality of heat collected and pump work required. Based on EXAR the suitable design parameters of chamfered rib groove roughness geometry are determined.