Abstract :
The aim of this work is to develop a mathematical model to determine the tilt that maximizes natural air flow inside a solar chimney
using daily solar irradiance data on a horizontal plane at a site. The model starts by calculating the hourly solar irradiation components
(direct, diffuse, ground-reflected) absorbed by the solar chimney of varying tilt and height for a given time (day of the year, hour) and
place (latitude). In doing so it computes the transmittance and absorbance of the glazing for the various solar irradiation components
and for various tilts. The model predicts the temperature and velocity of the air inside the chimney as well as the temperatures of the
glazing and the black painted absorber. Comparisons of the model predictions with CFD calculations delineate the usefulness of the
model. In addition, there is a good agreement between theoretical predictions and experiments performed with a 1 m long solar chimney
at different tilt positions.
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