Geometric optimization of thermally activated small scale solar chimneys for natural ventilation applying CFD simulations and measurements

Thermally activated solar chimneys could be an ideal solution to provide sufficient natural ventilation in regions with unsettled weather conditions. An optimized system would enable a sustainable and permanent operation of the natural ventilation system, saving energy and greenhouse gas emissions at the same time. This study analyzes the optimal geometric conditions of a thermally activated small scale solar chimney for natural ventilation. A schematic of such a system can be seen in Fig. 1. The analysis of the geometric parameters is conducted with CFD (computational fluid dynamics) simulations using ANSYS FLUENT. In addition, experiments with the same boundary conditions were carried out on a testing facility to verify the simulations. The investigations were done for air gap width of 0.1 m, 0.3 m and 0.5 m. The maximum volume flow was simulated and measured for a chimney air gap width of 0.3 m. The results of this study contribute to a better understanding of the thermally activated solar chimney concept and show the differences between the simulation and experimental results.