Solar Chimney: Natural Convection

Description

This project uses ANSYS Fluent to simulate natural convection in a solar chimney, a passive solar system central to renewable energy and sustainable building engineering. Solar chimneys use buoyancy-driven airflow, generated by solar heating of an absorber surface, to drive natural ventilation and passive cooling in buildings without mechanical energy input. This simulation examines how heat absorbed at the chimney surface drives air movement through the vertical channel.

Methodology

The solar chimney geometry is built in DesignModeler and meshed with a structured grid of 510,000 cells, refined in critical flow regions for accuracy. The Fluent setup activates the energy equation to capture temperature changes and includes gravity effects to model buoyancy-driven flow, with a heat flux of 55 W/m² applied at the absorber surface to represent solar heating.

Conclusion

Results include temperature, velocity, and pressure contours along with streamlines showing air circulation patterns within the chimney. The mass flow rate at 0.5 m height is reported at 0.128 kg/m³, characterizing the strength of the buoyancy-driven flow. These findings support the design and evaluation of solar chimneys for passive building ventilation, offering insight relevant to sustainable architecture, HVAC optimization, and renewable energy integration in energy-efficient buildings.