Numerical Study of Natural Ventilation Through a Roof Cavity for Reduction of Solar Heat Gain

AbstractThe thermal performance of a building is a major requirement to have a comfortable interior climate. Current standards of construction advice to make an open thermosyphon system into the roof under the tiles. This reduces the cost of the cooling energy in hot areas. For that a good design of these systems allows to maximize natural ventilation and to minimize the fraction of solar energy absorbed by the building. To evaluate the effectiveness of the air channel, a numerical model representing the natural convection in the thermosyphon was developed. Distributions of velocity, temperature and mass flow induced are determined. The results obtained are in good agreement with the theoretical ones. The objective of this work is to determine the optimal mass flow for a better ventilation of a roof cavity