NUMERICAL ANALYSIS ON THE THERMAL PERFORMANCE OF THE GLASS EVACUATED TUBE SOLAR COLLECTOR ADOPTING A FINNED TUBE

摘要

The performance of a glass evacuated tube solar collector is numerically investigated. The solar collector considered in this study consists of a two-layered glass tube and an absorber tube that has fins. The air is used as a working fluid. The length and the diameter of the glass tube are 1,200mm and 37mm, respectively. Three different shapes of absorber tubes are considered, and the performance of each solar collector is compared to find the best shape of the absorber tube for the solar collector performance. From the calculation, it is known that the performance of the solar collector is a strong function of the incidence angle of solar radiation and the copper tube diameter (or the fin width). The result shows that the thermal performance of the plate fin absorbers is sensitive to the incidence angle of solar irradiation. On the other hand, the thermal performance of the circular fin absorber is independent of the incidence angle. Since this calculation is for individual absorber tube, the performance of the solar collector system can be different.