Effect of natural ventilation and wind direction on the thermal performance of a building ceiling

Natural ventilation is rapidly becoming a significant part in the design strategy of buildings in situations where electricity is scare or non-existent and saving energy becomes highly important. The aim of present work is to reduce the ceiling temperature by natural ventilation through different opening locations (one window in the front façade and the other window in the rear wall) with sill height ratio of 0.27, 0.36, 0.45, 0.54, and 0.63. Wind tunnel and smoke tunnels were used to investigate the effect of opening locations on the temperature and heat transfer coefficient of a ceiling of a naturallyventilated room. Here, the ANSYS CFD software was used to determine the flow characteristics in the ventilated room with different opening locations and wind direction. Better flow pattern and heat transfer from the heated ceiling are observed when the front and rear openings are located nearest to the ceiling and center, respectively. An experimental correlation was obtained to predict the influence of sill opening height ratio of front and rear walls on the average heat transfer coefficient ratio of ceiling (h_av / h_o ) where h_o is the heat transfer coefficient in case of no wind.