Solar Radiation Effect on a Building at Different Hours

Description

This project investigates how solar radiation intensity and angle vary with time of day and their effect on surface temperatures and airflow in an outdoor urban environment, simulated in ANSYS Fluent. The study is anchored to a specific real-world location — Baku, Azerbaijan — and two specific times on June 21st, 8 AM and 3 PM, chosen to contrast morning and afternoon radiation conditions at the same site on the year's longest day. The environment includes a house, trees, and ground, with soil, brick, and wood material properties assigned respectively, so that conduction through solids, convection in the surrounding air, and solar radiation are all represented simultaneously. Free airflow passes through the domain at 10 m/s and 27°C. The geometry is built in Design Modeler and meshed in ANSYS Meshing with an unstructured grid of 2,054,294 cells.

Methodology

Radiation is modeled using the Discrete Ordinates (DO) model, the most comprehensive of Fluent's radiation formulations, capable of handling scattering, semi-transparent media, specular surfaces, and wavelength-dependent transitions by solving the radiative transfer equations over a finite set of discrete solid angles. Solar radiation is introduced through the Solar Ray Tracing model, with Baku's longitude, latitude, time zone, and the specific date and hour provided to the solar calculator, which derives the corresponding irradiation intensity and sun angle for each of the two time cases.

Analysis

The results include temperature and radiation heat flux contours for both the 8 AM and 3 PM cases. The maximum domain temperature rises from approximately 312 K at 8 AM to 318 K at 3 PM, a 6 K increase attributable to the higher radiation intensity and more direct sun angle later in the day. In shaded zones between the houses and under the tree canopy, however, the radiation flux received remains in the relatively narrow range of 50 to 70 W/m² across both time cases, indicating that shaded areas provide meaningful and consistent protection from the stronger afternoon solar load even as the broader environment heats up significantly.