Numerical simulations of smoke spread during solar roof fires

As the installation of solar roofs increases, so has the concern over fires. Smoke from a solar roof fire could spread into a building through roof openings and presents a challenge for existing fire protection strategies. To date, there have been insufficient studies on solar roof fire-induced smoke spread. In this study, we conducted computational fluid dynamics (CDF) simulations using Fire Dynamics Simulator (FDS) to better understand the mechanisms of solar roof fire-induced smoke spread and help with solar roof designs. First, the photovoltaic (PV) combustion model was created in FDS and validated by experimental data. A parametric study was then simulated to investigate the impacts of roof slopes and vent sizes on the smoke spread of the solar roofs. It was found that the roof slope has a significant effect on the fire smoke spread. As the roof slope increases, the region of separation, where the smoke and air are mixed, can extend from the leeward side of the building to the roof ridge. As a result, smoke could fill the attic and room more slowly, leading to a lower soot density and lower indoor temperature. When design a solar roof, both fire smoke protection and PV energy performance should be considered, especially for the low latitude regions where the PV optimal title angle regarding energy performance is small and leads to a higher risk of smoke infiltration.