Abstract:

A model for time dependent analysis of solar chimneys is presented. The energy balance equations for three components of solar chimneys, absorbing plate, cover glass and air-gap are discretized with respect to time using an implicit finite difference model. The discretized nonlinear energy balance equations are solved for numerous time steps over a 24-h period using the Newton–Raphson method. The time dependent solar irradiation is determined using the clear sky model. The model’s performances for var-ious parameters of solar chimney that affect the thermal mass of the absorbing plate are tested. It was determined that a solar chimney with a relatively large thermal-mass produces airflow well into night and early morning when no solar irradiance is present. Also, a high thermal mass of the absorbing plate results in smaller variations in the airflow rate. The results of the present model for a solar chimney with no thermal storage compare well with the previously published data.

Authors:

Mohammad H. Naraghi ∗, Sylvain Blanchard

Keywords:

Solar chimney

Modeling

Passive use of solar energy in buildings

Natural ventilation