Impact of window and air-conditioner operation behaviour on cooling load in high-rise residential buildings

Abstract

Space cooling is an important building energy end-use that was found in recent years to be significantly impacted by occupant behaviours. However, the majority of previous studies ignored the interplay between the operation of windows and air conditioners (ACs) on cooling load, particularly in building energy modelling. In addition, studies on the analysis of cooling load characteristics regarding high-rise buildings are insufficient. The vertical effect of high-rise buildings on cooling load remains vague. This study thus aims to examine how window and AC operation behaviours impact the cooling load of high-rise buildings in an urban context demonstrated by a real-life typical 40-floor residential building in Hong Kong. This study investigates window and AC operation behaviours jointly and examines the vertical effect on cooling load by using agent-based building energy modelling (BEM) techniques and initiating stochastic and diverse behaviour modes. A carefully designed questionnaire survey was conducted to help build behaviour modes and validate energy models. Ninety building energy models were established integrating meteorological parameters generated by the computational fluid dynamics (CFD) programme for ten typical floors and nine combinations of window and AC behaviour modes. The results show that comfort-based AC modes and schedule-based window modes yielded the lowest cooling load. Considering the combined effect of AC and window uses, the maximum difference in cooling loads could be 26.8%. Behaviour modes and building height induce up to 32.4% differences in cooling loads. Besides, a deviation between the behaviour modes and height on the cooling load was found. The findings will help develop a thorough energy model inferring occupants’ window and AC behaviour modes along with the building height in high-rise residential buildings. The findings indicate that the interaction impact of window and AC behaviour modes and height should be jointly considered in future high-rise building energy modelling, building energy standards, and policymaking.