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Research Status on Solar Chimney for Natural Ventilation Enhancement

  • SU Yaxin;LIU Zhongbao
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  • School of Environmental Science and Engineering, Donghua University, Shanghai 201620, China

Received date: 2011-02-28

  Revised date: 2011-09-01

  Online published: 2011-09-28

Abstract

Natural ventilation is an energy efficient passive cooling technology and it uses wind or thermal buoyancy to deliver fresh air into the buildings in order to maintain a good indoor air quality. Comparing with mechanical ventilation, natural ventilation has obvious energy-saving advantages. Solar Chimney (SC) is a vertical or inclined channel that utilizes solar radiation to cause a temperature rise and density drop for the air flowing through the chimney, therefore enhances the natural ventilation. First, two types of typical solar chimney, namely, Trombe wall-type and inclined roof-type solar chimney, and their basic principle to enhance natural ventilation are briefly introduced. Then, the parameters that influence the performance of natural ventilation of the solar chimney are discussed in detail. The major methods and result are listed based on the review of the research works on solar chimney by different authors. The height and depth (the distance between the glass cover and absorber wall) of SC influence the natural convection flow process and the temperature rise of air in the SC channel and furthermore influence the ventilation rate of the SC strongly. The ventilation air i.e. the air flow rate increases with the increase of SC depth. The air flow rate decreases when the SC depth exceeds an optimal value. A reverse flow appears near the top of the SC channel when the ratio of SC depth to height is larger than 2.5 and the increase of natural ventilation rate is limited. The effect of the SC structure and its inclined angle on ventilation is related to the geographical location and climate conditions. The modeling of SC ventilation includes the mathematical modeling that is based on the energy conservation analysis on the heat transfer process of the air on the wall surfaces and the numerical simulation of the flow process that is based on Computational Fluid Dynamics (CFD) method. Based on the literature review, the issues that need to be improved in solar chimney study are analyzed.

Cite this article

SU Yaxin;LIU Zhongbao . Research Status on Solar Chimney for Natural Ventilation Enhancement[J]. Science & Technology Review, 2011 , 29(27) : 67 -72 . DOI: 10.3981/j.issn.1000-7857.2011.27.010

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