An experimental study of solar air heater using arc shaped wire rib roughness based on energy and exergy analysis

In the present study, energy and exergy analysis has been evaluated for roughened solar air heater (SAH) using arc shaped wire ribs. To achieve this aim, two different types of flow arrangement have been considered. These arrangements are: apex upstream flow and apex downstream flo. In addition to this, a smooth duct SAH has been used for comparative study. The experiments were performed using the mass flow rate of 0.007– 0.022 kg/s on outdoor condition at Jamshedpur city of India. The absorber plate roughness geometry has been designed with relative roughness height 0.0395, rib size 2.5 mm, relative roughness pitch 10 and arc angle 60◦ . The energetic and exergetic performances have been examined on the basis of the first and second law of thermodynamics. According to the results, there is observed to be the maximum thermal efficiency and exergy efficiency as 73.2% and 2.64%, respectively, for apex upstream flow SAH at 0.022 kg/s, while, at same mass flow rate the maximum thermal efficiency and exergy efficiency is obtained as 69.4% and 1.89%, respectively, for apex downstream flow SAH. In addition to this, results reported that the maximum outlet temperature and temperature difference observed at lower mass flow rate. Also examined the outlet air temperature of SAH with various mass flow rates is very important for both analysis.