Experimental investigation and thermal analysis of solar air heater having rectangular rib roughness on the absorber plate

This study presents experimental investigation and thermal analysis of solar air heater having rectangular roughness on the absorber plate. The solar air heater used for the experiment was locally fabricated. The maximum intensity of solar radiation, ambient and solar air heater temperature were 827.87 W/m2, 33.77 and 112.0 °C respectively during the day time period of 9:00–18:00 h operation. The calculated thermal efficiency value ranged between 14.0 to 56.5%. The simulated minimum and maximum temperature of the solar air heater were 21 and 127 °C respectively, which were in reasonable agreement with experiment result of 20 and 112 °C. Thus, the solar air heater was considered capable of handling processes such as drying of various agricultural products, water heating etc. with temperature control mechanism. Keywords: Solar air heater, Thermal efficiency, Heat transfer coefficient, Rectangular rib, Comptational fluid dynamics