Thermal and effective efficiency based analysis of discrete V-down rib-roughened solar air heaters

A parametric investigation of discrete V-down rib-roughness geometry in the absorber plate of solar air heater has been carried out and results obtained are compared with those of conventional flat plate solar air heater. The thermal and thermohydraulic performance evaluation has been carried out for various values of Reynolds number and roughness parameters of discrete V-down rib-roughness geometry in the absorber plate of solar air heater duct. The performance curves are plotted in terms of Reynolds number and temperature rise parameter. The discrete V-down rib-roughened solar air heater performs better as per thermal efficiency or heat energy gain criteria for the investigated range of Reynolds number and rib-roughness parameters. The thermal efficiency is high for discrete V-down rib-roughened solar air heater due to higher turbulence; however, the pumping power required for air flow also increases. The thermohydraulic performance on the basis of effective efficiency is a more suitable criterion as it...