Massimo Fiorentini

Ventilative cooling technologies have the potential to be an effective measure to reduce buildings energy consumption, by meeting some or all of the cooling requirement of a building without the need for mechanical cooling. Mixed-Mode (MM) buildings utilise both natural and mechanical cooling systems to meet their thermal energy demand. These buildings are able to guarantee that thermal comfort conditions are maintained, whilst exploiting the cooling potential provided by the climate. Effective management of the cooling systems in MM buildings is important to ensure that comfort is maintained and free cooling is exploited when available. While the implementation of hybrid ventilation systems is becoming more common, the current industrial and academic research state-of-the-art provide different and sometimes contrasting approaches to the management and evaluation of MM buildings. The current review provides an overview of studies into MM buildings performed in the last 10 years, analyzing in detail key factors that determine the potential of a building to save energy, including simulations inputs assumption, comfort standard used for evaluation, building and Heating, Ventilation and Air Conditioning (HVAC) systems typologies and control strategy employed. A detailed analysis of the papers which had a focus on methods for control of hybrid ventilation system was undertaken. This highlighted the importance of coordination between systems to ensure operational effectiveness and showing that while the majority of the studies employed classical control techniques, predictive control methods were the most investigated approaches to fully exploit the potential efficiency of MM buildings.