Airflow and thermal comfort evaluation of a room with different outlet opening sizes and elevations ventilated by a two-sided wind catcher

Abstract

Wind catchers as passive cooling systems contribute to the enhancement of air quality, thermal comfort, and reduction of energy consumption in the residential sector. In this paper, the indoor flow structure, crossflow ventilation characteristics, and thermal comfort of a room integrated with a two-sided wind catcher is numerically investigated. A mixed-climate condition and experimentally validated room dimensions are utilized to define the physics of the problem. 3D steady-state RANS CFD simulations, with different turbulence models for a reference case are simulated, and their performance is compared with the published literature. The following analyses are conducted based on a validated SST k-ω model and a fixed reference case dimensions with (1) five different room outlet elevations (top, reference case, middle, front of room inlet opening, and floor) and (2) four different outlet areas to the wall ratio (10%–40%). The results show that the room outlet mass flow rate increases up to 26% by decreasing the room outlet elevation from the top to the floor; the front and floor outlet elevations obtained the optimum thermal comfort metrics. At a specific room outlet opening elevation, increasing the room outlet area to wall ratio increases the mass flow rate; the 30% aspect ratio obtained the desired temperature stratification and velocity field. These results can be combined with architectural metrics towards improving user comfort in the buildings.