Improved thermo-hydrodynamic field quality in the solar chimneys

This work is a part of a series studies on the influence of the geometric parameters on the thermo-hydrodynamic behavior of the airflow in solar chimney systems. Solar chimneys are intended to be used either in the air conditioning and drying or in the production of electricity. In this paper we are particularly interested in the effect of the shape of some parts of solar chimney component like the shape of the cover-tower junction, or the convergent-divergent tronconique tower. For this purpose the flow transport equations were modeled and solved numerically for different geometrical shapes using the Finite Volume Method in Generalized Coordinates. We find that a few geometric configurations generated flow perturbations, which reflected on the thermo-hydrodynamic behaviors. Geometrical shape modifications can eliminate this dissipative perturbation. As it has been shown that the most important solar chimney dimensions in the hydrodynamic field control was the tower size, we gave special importance to the tower shape. We tested the influence of the tronconique convergent and divergent tower respecting the flow cross section. The divergent shape increases the mass flow rate but for a certain divergence angle the mass flow drops. on the other hand, the convergent tower shape gives reverse results by decreasing mass flow rate but the velocity at the outlet is greater due to a reduced flow cross section.