A Model to Estimate Ambient Conditions and Behavior of the Airflow Inside a Solar Chimney

Abstract

This paper presents models to estimate the environmental conditions and the behavior of the airflow within a prototype of a small-scale solar chimney located in Belo Horizonte, Brazil. A correlation from the literature for diffuse radiation, based on clearness index and global radiation was evaluated. A model from the literature was used to estimate ambient temperature on the device. Results for both parameters were compared to experimental data. An energy balance was applied to find the heat interactions between the ground, airflow, coverage and environment, based on the estimated incident solar radiation and ambient temperature. Literature correlations were used to estimate convective heat transfer coefficients. Consolidated correlations were then applied to estimate mass airflow and outlet temperature of the airflow inside the prototype. Results were compared to experimental data for four days in autumn, and good results were found. The model was then used to estimate the airflow parameters in a period of one year. The analysis performed is transient, with results provided for each hour of the day, for 365 days.The results showed good accordance with experimental data. The greater differences were found to the mass flow rate at night.