Performance analysis of a solar air heater modified with zig-zag shaped copper tubes using energy-exergy methodology

This study has been performed to enhance the performance of the solar air heater (SAH) using copper tubes to the absorber plate. Thermodynamic analysis of the SAH with and without copper tubes attached to the absorber plate has been performed. The improvement potential, sustainability index, and waste energy ratio have also been studied. From the results, it has been found that the thermal and exergy efficiency of the absorber with copper tubes is higher as compared to the absorber without copper tubes for the same climatic conditions. The energy efficiency of the SAH with and without copper tubes absorber was ranged from 14.53 to 20.36% and 12.45-17.53% with an average of 18.26% and 16.29%, respectively in the natural convection mode. The exergetic efficiency was ranged from 1.2 to 1.939% and 0.95-1.53% with an average of 1.69% and 1.41%, respectively. Energy and exergy analysis of the SAH with copper tubes attached absorber have also been performed for the forced convection mode at varying air flowrate from 0.0166 to 0.058 kg/s. The maximum value of energy and exergy efficiency of the SAH was obtained as 62.8% and 5.848%, respectively at the airflow rate of 0.05 kg/s.