Numerically predicting the effect of fin on solar Trombe wall performance

Abstract

The fin can provide a prominent effect on the Trombe wall performance utilizing solar energy. The natural convection heat transfer in Trombe walls with rectangular fins was numerically investigated in this paper. By developing a three-dimensional model with RNG k-ε turbulence and S2S radiation models, the effects of fins height, fins spacing, and fins arrangement on the thermal performance for Trombe wall were predicted. In addition, the comparison between the Trombe walls with and without fins was carried out. The results indicate that the developed numerical model is valid and can be used to predict the performance of finned Trombe wall. For Trombe wall with vertical fins, the outlet temperature and thermal efficiency increase with fins height, while thermal efficiency first rises and then drops with fins spacing. With horizontal fins height increasing, the ventilation rate and thermal efficiency first peak and then descend sharply. The outlet temperature and thermal efficiency of Trombe wall with vertical fins are higher than those of Trombe wall without fins in all cases, while the ventilation rate is the opposite. In contrast to the influence on the outlet temperature, the ventilation rate and thermal efficiency are contributed the significant negative impact by the greater horizontal fins height. The maximum thermal efficiency can be obtained for different fins arrangements, and the value is significantly higher for Trombe wall with vertical fins, which is 59.41%, a relative increase of 23.7% compared to Trombe wall without fins.