Impact of outdoor air on cooling and heating demand of nearly zero energy residential buildings

The proposal of dual carbon goal has promoted the rapid development of energy saving and carbon reduction in the building sector, and the research and application of nearly zero energy buildings with low cooling and heating demand has become a hot topic in the industry. In this paper, the numerical simulation of typical nearly zero energy residential buildings is carried out to study and analyse the annual cooling/heating demand characteristics of typical urban nearly zero energy residential buildings in different climate zones under different outdoor air utilization scenarios. The calculation results show that the annual heating demand is reduced by 46.99%-54.92% by utilizing outdoor air heat recovery in five climate zones, the annual cooling demand is elevated in severe cold zone and cold zone after utilizing outdoor air heat recovery, and the annual cooling demand is reduced by more than 10% in hot summer and cold winter zone, hot summer and warm winter zone and mild zone. From hot summer and warm winter zone to severe cold zone, the introduction of outdoor air through the opening of windows during the cooling season can reduce the annual cooling demand by 2.24-4.84 kWh/m2. The effect of the organized utilization of outdoor air for cooling during the cooling season on the annual cooling demand is related to the outdoor air volume, and selecting the appropriate outdoor air volume can effectively reduce the annual cooling demand. The study of the impact of different outdoor air utilization methods on the cooling and heating demand of nearly zero energy buildings can provide a reference for the optimization of HVAC system configuration and the research and development of specialized products.