Effects of inlet area on heat transfer performance of a solar chimney

Integrated passive cooling technique in building is expected to save energy and create thermal comfort. Solar chimney has been adopted to building design as an effective technique for natural ventilation. The working principle of solar chimney is based on thermal effect, particularly natural convection heat transfer. In this paper, heat transfer performance of a solar chimney with different contracting inlet areas is presented. Furthermore, the effects of major dimension, i.e. ratio of chimney gap and height G/H, are also investigated. As the ratio of the inlet area and the gap, Ai/G, from 90% to 20%, the Nusselt number is strongly affected for G/H below or equal to 5%; while for G/H above or equal to 20%, it showed minor influence. In addition, with G/H of 10% and inlet area from 40% to 60% of the gap, heat transfer coefficient have considerable improvement from 5.3% to 6.1%. The result suggests that G/H = 10% and Ai/G in the range of 40% to 60% are optimal design. Keywords: Solar chimney, inlet area, CFD, heat transfer.