PERFORMANCE ENHANCEMENT OF A DOUBLE PASS SOLAR AIR HEATER USING V-CORRUGATED ABSORBER PLATE AND STEEL WOOL

This study included an experimental investigation for the purpose of improving the performance of a conventional double-pass solar air heater at the climatic conditions of Mosul city/Iraq by replacing the flat absorber plate of the conventional solar air heater with a V-corrugated plate and adding steel wool in the lower passage of the air heater while keeping all dimensions constant for the two heaters. The two heaters were operated together under the same conditions and at a constant air flow 0.0416 kg/s. The results showed that the thermal efficiency and air temperature exiting from the solar heater can be improved using the improvements that have been indicated. As the average thermal efficiency was 66.78% for the improved heater and 30.35% for the conventional heater in the month of March 2020. The results also showed that the improved heater retains the heat gained from solar intensity for a longer period compared to the conventional heater at a constant solar radiation intensity. These improvements also contributed to a clear increase in the temperature of the air exiting the system. The maximum difference in the temperature of the air entering and leaving the heaters in February 2020 reached 28.75°C, and 16.75°C for the improved and conventional heaters, respectively. The results also proved that the improvements over the conventional system led to a reduction in the amount of heat lost from the solar heater.