Numerical study of the optimum width of 2a diurnal double air-channel solar chimney

A conjugate heat transfer analysis of a double air channel solar chimney (SC-DC) aiming to determine the configuration that maximizes the mass flow rate of the system is presented. The design modifications consisted on two geometrical parameters: 1) the separation between the absorber wall and the glass covers that form the air channels (b), and 2) the height of the system (L). A code based on the Finite Volume Method was developed and a k-ω turbulence model was used to model air turbulence in the SC-DC. The code was validated and it showed a good agreement with experimental data reported in the literature. We found that the optimal configuration of the SC-DC under the considered conditions is L = 2 m and b = 0.125 m. The optimum L of the SC-DC is similar to the value reported for a conventional chimney, whereas the optimum b is smaller than the one of a conventional chimney. The optimal configuration of the SC-DC had a thermal efficiency of 38.5% and a mass flow rate of 0.1072 kg/s when it receives a beam solar radiation of 700 W/m2 and a diffuse solar radiation of 100 W/m2.