Energy, Exergy and Economic Analysis of Solar Air Heaters with Different Roughness Geometries

Artificially roughened surface is a common method to enhance the heat transfer in a flow passage. Energy, exergy and economic analysis of solar air heaters with different roughness geometries have been done. To improve the performance of the solar collector, 4 different types of roughness on the absorber plate have been used. The mathematical model has been validated with analytical and experimental results available in the literature with acceptable deviation. On the basis of numerical calculations, it has been concluded that roughened surface improves energy and exergy efficiency of solar air heater by 14 % and 1%, respectively. Further it was found that the most efficient roughness is Discrete V Rib and the least expensive roughness is U-Shape turbulator. NSGA II and TOPSIS algorithms used to select the best roughness geometry.