Natural ventilation usability under climate change in Canada and the United States

Natural ventilation can be incorporated into buildings to decrease energy use and the associated greenhouse gas emissions of buildings. However, mechanical cooling has largely replaced natural ventilation in commercial buildings in Canada and the US. This study evaluates the potential for natural ventilation under climate change. To this end, a typical office space in a mixed-mode building in 14 cities representing the major climate zones in Canada and the US was simulated to assess the usability of natural ventilation under the predicted climatic data for the years 2050 and 2080. A rule-based model for change-over between natural and mechanical ventilation modes was developed on the basis of the adaptive thermal comfort model. The potential impact of occupants was also simulated using an existing stochastic occupants' window use model. The simulation results show that the natural ventilation usability with rule-based control generally decreases under climate change. The stochastic model indicated the risk of overheating resulted from inefficient window use. Climate change leads to higher cooling energy use, which can be reduced considerably, especially in temperate climates, using natural ventilation with rule-based control. However, the stochastic model yielded to the reduction in the energy saving rates.