Exergetic performance evaluation of solar air heater having V-down perforated baffles on the absorber plate

Baffles serve as heat transfer augmentation features in solar air heaters; however, they increase pressure drop in flow channels. Perforated baffles are relatively good heat transfer augmentation features with superior performance over conventional smooth duct solar air heater and as a result find application in some solar air heaters. The exergy method is employed to in determining the roughness parameters, as second law-based exergy analysis is suitable for design of roughened solar air heaters. The exergetic efficiency of V down perforated baffled roughened duct solar air heater is studied analytically, and the results obtained compared with conventional system. Results indicate that high efficiency with optimum V down perforated baffle improves the heat absorption and dissipation potential of a solar air heater. Design plots are prepared to predict the optimum roughness parameter as a function of temperature rise parameter.