Performance evaluation of solar air heater having V-ribs with symmetrical gaps in a rectangular duct of solar air heater

摘要

An investigation has been carried out to evaluate the performance of a solar air heater duct roughened with V-ribs with symmetrical gaps to enhance heat transfer. The roughness produced for enhancing heat transfer from the absorber plate also enhances pressure drop due to increased friction. Heat transfer enhancement of the absorber plate has been experimentally determined by using V-ribs with symmetrical gaps. The duct has a relative roughness height (e/D) of 0.0433, a relative roughness pitch (P/e) of 10 and an angle of attack (α) of 60°. Relative gap width (g/e) and number of gaps (Ng) were varied in the range of 1-5. The maximum enhancement in the Nusselt number and friction factor is observed to be 2.59 and 2.87 times, respectively, as compared to the smooth duct. The relative gap width of 4 and the number of gaps of 3 show the maximum value of thermohydraulic performance parameter.