Impact of climate change on energy saving potentials of natural ventilation and ceiling fans in mixed-mode buildings

Mixed-mode (MM) ventilation strategy has been used in many buildings to reduce energy use. This strategy can be more effective if used along with ceiling fans (CF). The MM ventilation and CF energy-saving potentials are often evaluated under present climate conditions. However, their energy-saving potentials greatly depend on climate characteristics and may change over time under climate change. This research aims to answer this question: how will the energy-saving potentials of MM ventilation with/without CF alter in the future in different Australian climates? To this end, a rule-based control model was developed based on the adaptive thermal comfort model to control air-conditioning, natural ventilation, and ceiling fans modes of operation. This model was implemented in a typical office building in six cities with different climates in Australia under present and two future climate scenarios. It was found that the MM ventilation strategy has moderate to significant cooling energy saving potentials in different Australian climates. Integrating CF into MM ventilation can provide an additional cooling energy saving; however, the scale of additional saving depends on the climate characteristics, reaching up to 23% under present conditions and 15% under the future climate conditions. The simulation results show that the energy saving potential of MM ventilation, with and without CF application, may decrease, increase or remain almost constant in the future based on the climate zone.