Effects of suction flow on the performance of a solar chimney

Abstract

Solar chimney has been applied on various aspects of building physics and green design. It makes natural ventilation based on stack effect from absorbing solar radiation. A Computational Fluid Dynamics (CFD) method has been widely utilized to model the heat transfer and air flow inside the chimney. The appearance of reverse flow is one of the elements affecting induced results from CFD models. In this study, we examined influences of the suction flow to suppress the reverse flow at the outlet of the air channel. The suction height, suction width and the velocity of the exhaust fan were investigated. The induced flow rate and temperature rise of the chimney were compared to the base case, which has no suction flow. It is observed that the ratio of Qsc and Qbase, which are the induced flow rate at the outlet of the chimney which has exhaust fan and induced flow rate of the base case, respectively, increases with the width, w, and the height above the inlet, h, of the suction port then gradually approaches a constant of about 1.25 when w and h are higher than 0.02 m and 0.15 m correspondingly. Additionally, one advantage of the suggested solution is to lower the noise from the fan to the room.