Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
Numerical analysis of a solar chimney for building ventilation
Submission Author:
Cyro Albuquerque Neto , SP , Brazil
Co-Authors:
Vinicius Branzani Leite, Thales De Freitas Villas Bôas, Cyro Albuquerque Neto
Presenter: Vinicius Branzani Leite
doi://10.26678/ABCM.COBEM2023.COB2023-0238
Abstract
The objective of the present work is the numerical analysis with CFD of the performance of a conventional solar chimney used to ventilate an environment. The application of solar chimney has been studied recently in the scientific literature for heating or cooling environments. Most studies are experimental, and the literature lacks numerical studies on the subject. The transport phenomena inside the chimney are complex, with vortices formed by natural convection and significant influence of external conditions, such as wind, rain, and changes in solar radiation. Solar chimneys can benefit from being a passive and sustainable HVAC solution, which can help reduce energy consumption. The CFD simulation of this device can comprehensively evaluate the phenomena involved. In this work, CFD simulations with the software Ansys CFX were performed and validated with the group's experimental data on a solar chimney 2 m in height, with 50 and 150 mm thickness cavities. The chimney is appropriate to use in a warm climate, with an air inlet from the indoor ambient at the bottom of the solar chimney and the air outlet to the external ambient on the top. Appropriate conditions were used in the simulations for natural convection phenomena, with mesh refinement for representing the boundary layer and large gradients. A far-field was included around the chimney to circulate the air between the outlet and the inlet. The influence of different turbulence models was investigated, which significantly impacts the velocity profile's behavior. It was found that some of the models can accurately represent the experimental data for temperature. Nevertheless, for the air velocity, they can represent the shape of the velocity profile curve but with lower values than the experimental ones. Some analyses were also included to verify the effects of air humidity and hot wall temperature. Both cases have little effect on the behavior of the chimney.
Keywords
Natural Convection, Solar Chimney, Passive Ventilation, Heat transfer
