Performance Analysis of an Efficient New-Design Solar Air Heater by CFD Method

Abstract

The main contribution of this study is to present a modified V-corrugated grooved absorber plate in the construction of plane solar air heaters for higher performance. The combined effects of extended heat transfer area due to the V-shaped absorber, the suction process by the grooves that maintains the convective flow closed to the heated absorber and the jet impingement enable high efficiency of the proposed solar collector. For simulation purposes, the conduction equation is employed for temperature computations inside the solid elements, while the turbulent airflow equations are solved based on the CFD method using the κε− turbulence model. The present finite element-based analysis is performed using the COMSOL Multi-physic software. To demonstrate the rate of irreversibilities in a solar collector, the entropy generation due to heat transfer and viscous friction and, accordingly, the second law efficiency are computed at different steady operating conditions. The numerical procedure is validated by comparing the obtained numerical findings with the experimental results reported in the literature. From the obtained results, it is found that the proposed absorber plate has a triple-edged sword positive effect on the solar air heater performance, such that the thermal efficiencies up to 80% are computed. Moreover, about 10% improvement in the thermal efficiency of the proposed solar collector compared with its competitor (solar air heater with a simple V-corrugated absorber) reveals the positive impact of the designed absorber plate. Also, the increase in the height of V-shaped absorber from 𝐻𝐻0=2 𝑐𝑐𝑐𝑐 𝑡𝑡𝑡𝑡 𝐻𝐻0=4 𝑐𝑐𝑐𝑐 leads to about 11% improvement in the heater thermal efficiency. The numerical findings can be considered as a good reference to find an alternative for efficient solar collectors.