Conference Proceedings - 2021

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Browsing Conference Proceedings - 2021 by Subject ""Computational fluid dynamics"
  • Publication
    Effects of heated cavities below and above the air channel on the performance of a solar chimney for natural heating
    ( 2021)
    Y. Q. Nguyen
    ;
    V. T. Nguyen
    Exploring solar radiation, solar chimneys are widely used in sustainable building design. Solar chimneys can ensure thermal comfort in a house by generating a heating or cooling air flow. For heating applications, the induced air flow is heated and supplied back to the house. In this study, the air flow and heat transfer in a solar chimney for heating were modelled by a numerical simulation based on Computational Fluid Dynamics (CFD) technique. An investigation on the system performance was carried out with the presence of a heated cavity above the top and below the bottom of the air channel. The length and the width of the cavity and the chimney gap have a strong influence on the flow rate and temperature rise through the chimney. The results showed that an appropriate dimension of the heated cavity can enhance the performance of the solar chimney
  • Publication
    Effects of the top extension of the domain in CFD simulation of solar chimneys
    ( 2021)
    T. N. Huynh
    ;
    Y. Q. Nguyen
    Solar chimneys have been widely used for natural ventilation of buildings. It absorbs solar radiation to create stack effect to induce air flow for ventilation. To model air flow and heat transfer inside solar chimneys, numerical models based on Computational Fluid Dynamics (CFD) have been broadly employed. The size of the computational domain is one of the factors influencing computed results from CFD models. In this study, we investigated effects of the extension of the domain above the outlet of the air channel as the gap and the height of the air channel changes. Two types of the computational domains were studied. The small domain has identical physical size with a cavity inside the solar chimney while the large domain contains both the cavity and the ambient air surrounding the chimney. The induced flow rate and temperature rise of the chimney were computed and compared between those domains. It is seen that to ensure the changes of both flow rate and temperature below 1.0%, the required extension, h, of the domain above the outlet of the air channel is a function of the gap – to – height ratio G/H, not only the gap. Specifically, for G/H in the range of 0.1 – 0.4 in this study, the required h/G rises from 10 to 30