Investigation of Performance Improvement in a Solar Air Heater Equipped with Impinging Jets: A Three-Dimensional Numerical Simulation

Abstract

With the continuous advancement of human civilization, the demand for energy has significantly increased, leading to a heightened need for energy resources. Effectively harnessing solar energy, as one of the most promising sources of energy, is crucial today. Among various applications, solar water heaters have gained widespread adoption, prompting researchers to focus on enhancing their efficiency. This study investigates the use of impinging jets to improve the performance of solar water heaters, numerically, to examine the impact of impinging jets positioned at the absorber plate. A total of 160 configurations were analyzed, assessing the effects of Reynolds number, turbulence intensity, jet diameter, and jet height on the Nusselt number. Operating within a Reynolds number range of 10,000 to 25,000, the results indicate that the PEC increases up to sixfold, while the Nusselt number rise as much as ninefold compared to conventional heaters without impinging jets. The highest cooling effect on the absorber plate, associated with an increase in the Nusselt number, is observed at a Reynolds number of 25,000, achieving a Nusselt number of 495.6. Furthermore, increasing the jet height to half the height of the cooling channel yielded significant performance improvements.