Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
A comparison between analytical and numerical results for the performance of a small-scale solar chimney
Submission Author:
Cristiana Brasil Maia , MG
Co-Authors:
Cristiana Brasil Maia, Janaína de Oliveira Castro Silva, Matheus Augusto Ferreira Soares , Elizaldo dos Santos
Presenter: Cristiana Brasil Maia
doi://10.26678/ABCM.COBEM2023.COB2023-0203
Abstract
Solar chimneys are devices that use solar energy to generate a hot airflow. In large devices the airflow is used to run a wind turbine; nevertheless, great dimensions are required to generate power at competitive prices. Small prototypes are used to dry agricultural products or to provide natural ventilation. In this work, it was developed an unsteady analysis of the airflow inside a small-scale solar chimney. A mathematical model was developed for the temperature of the airflow at the outlet system, for the ground surface temperature, and for the mass flow rate reached by the airflow. It was also developed a CFD model for the airflow inside the system, based only on the ambient temperature, incident solar radiation, and wind speed. For both models, experimental data obtained in a small prototype built in Belo Horizonte, Brazil, were used. The results from analytical and numerical results were compared. It was observed that the ground surface temperature presented the lower differences between the models, and the outlet airflow temperature presented the higher differences. For the mass flow rate, the best results were found for the periods without solar radiation. This behavior can be attributed to simplifications of the analytical model.
Keywords
Solar Chimney, small-scale solar chimney, Computational fluid dynamics (CFD), analytical model
