Impact of Night Ventilation on Indoor Thermal Environment of Residential Buildings under the Dual Carbon Target: A Case Study of Xi’an

Effectively reducing the energy consumed by buildings under the dual carbon targets in China was our focus in this study. We used experimental methods to test and analyze the indoor air and average radiation temperatures in a specific apartment building in Xi’an. We compared the impact of night ventilation on the indoor thermal environment using the EnergyPlus software V9.5.0. The results showed that night ventilation is suitable for the typical summer temperatures in Xi’an when the daily temperature range is larger than 6 °C. Night ventilation technology can be used for 76 days from June to August, accounting for approximately 82.6% of this period. The indoor air and average radiation temperatures both decrease with the adoption of night ventilation, with these temperatures decreasing with an increase in the daily temperature range. When the daily temperature range increases from 3 °C to 15 °C, night ventilation can reduce the indoor average and radiation temperatures by a maximum of 1.07 and 0.47 °C, respectively, on typical meteorological days. When the daily temperature range is 15 °C, the maximum energy savings is 4.85 kWh/d, and the cost saving index for air conditioning operation is 0.065 CNY/(m2·d). With a daily temperature range of 3 °C, the air conditioning operating costs are reduced by 63.7%. Our study provides a reference for building energy conservation and the creation of comfortable indoor thermal environments under the dual carbon target: a carbon peak before 2030 and carbon neutrality before 2060.