Computational Fluid Dynamics and Experimental Analysis of the Heat Transfer in a Room With a Roof Solar Chimney

This study reports a numerical-experimental analysis of heat transfer and airflow in a scaled room with a heated wall coupled with a double-channel vertical roof solar chimney. For the experimental part, a parametric study was performed in the thermal system, considering different values of heat flux supplied to a vertical wall of the scaled room (75 and 150 W/m²) and the absorber surface of the solar chimney (151 and 667 W/m²). Experimental temperature profiles were obtained at six different depths and heights, and experimental heat transfer coefficients were computed for both heated surfaces. The renormalization group k-ɛ turbulence model was evaluated against experimental data using computational fluid dynamics software. With the validated model, the effect of the heated wall and solar chimney on temperature fields, flow patterns, and heat transfer convective coefficients are presented and discussed. The cases with heat flux on the heated wall of the scaled room produce the biggest air changes per hour (ACH), being 30.1, 31.2, and 23.4 ACH for cases 1 to 3, respectively, while cases with no heated wall produce fewer ACH (11.72 and 12.28 for case 4 and 5). The comparison between cases with and without heat flux on one vertical wall but the same solar chimney heat flux shows that the ACH increases between 154% and 156%, respectively.