Numerical study of the impact of make-up air in a residential kitchen on the heating and cooling demands of ULEBs

Abstract

Ventilation significantly impacts energy consumption in ultra-low-energy buildings (ULEBs). However, in Chinese residential kitchens, the influence of mechanical ventilation formed by range hoods and make-up air systems on energy consumption has received limited attention. This study assesses the heating and cooling demands in ULEBs resulting from kitchen make-up air across different climate zones in China. The results reveal that in natural make-up air mode, there is a substantial rise in annual heating demand in cold and severe cold zones and a notable increase in annual cooling demand in hot summer and warm winter as well as hot summer and cold winter zones. Additionally, the natural make-up air mode often poses challenges in maintaining a satisfactory thermal environment in kitchens during both heating and cooling seasons. Conversely, the mechanical make-up air mode, especially with pretreatment of outdoor air to ensure thermal comfort in kitchens, significantly elevates both annual heating and cooling demands, making it hard for the building to meet the ULEB specifications, particularly in cold and severe cold zones. Furthermore, despite a generally small increase in annual cooling demand, the percentage rise in heating demand often exceeds the ULEB limits, ranging from 12.0% to 36.0%, depending on the climate zone.