The determination of energy and exergy parameters of a newly designed solar air collector

This experimental investigation has been carried out to study on energy and exergy analyses of newly designed solar air collector with porous surface by preparing three different experimental setups. For the first experimental setup, a flat surface was used without spreading any substance on the absorbent surface, copper wire mesh was laid on the absorber plate in the second setup, copper wool was laid on the absorber plate in the third setup In this way, the absorber plate was aimed to absorb more heat and impair the the thermal boundary layer of the flow. The tests were repeated for different collector types at 0.030, 0.035, 0.044 and 0.055 kg /s mass flow rates. For the efficiency calculation, the temperature difference of the air entering and leaving the collector, the velocity of the air, the intensity of the radiation and the pressure difference in the collector were measured. The maximum thermal efficiency of flat surface collectors at the rate of 0.035 kg/h mass flow rate was found 50%; the maximum thermal efficiency at the rate of 0.044 kg/h was found to be 68%. The maximum thermal efficiency of the collector for which copper wire mesh was laid on the absorber plate was found 58% at the 0.035 kg/h mass flow rate and 77% at the 0.044 kg/h mass flow rate. The first and second experimental setups were checked out at different collector angles. In addition, the thermal performance of the newly designed solar air collector with porous surface and the thermal performance of the collector with flat surface were examined at different collector angles. By comparison with the efficency of the collector having flat surface at the angle of 35° and the efficiency of the collector with wire mesh at 25° at the same mass flow rate, it has been found that the angle of collector has more important role on the efficiency rather than the absorbent surface of collector. Maximum thermal efficiency of 57% for a mass flow rate of 0.035 kg/s for a collector with copper wool laid on the absorbent surface; The maximum thermal efficiency for the mass flow rate of 0.044 kg/h was found to be 73%. The thermal-hydraulic efficiency values of the collectors are between 20% and 70%. Exergy efficiency calculated from the experimental results are estimated to be between 2% and 11%.