Measurement of the indoor environment and heating energy consumption of a passive office building in severely cold region, China

Passive ultra-low energy buildings represent an effective strategy for energy conservation and emission reduction within the global building industry. The prolonged and cold winters in severely cold regions of China necessitate substantial heating energy consumption. The study utilized a combination of overall surveys and long-term tracking surveys to evaluate the indoor environment and energy consumption in a passive office building situated in severely cold region under different heating modes over 2 years. The results show that the average temperature and indoor air quality (IAQ) can meet the standards at most moments. However, the average relative humidity tends to fall below the specified lower limit. Nevertheless, the Predicted Mean Vote (PMV) index suggests that the indoor environment provides a comfortable thermal experience for humans. The heat pump air conditioning (HPAC) system operation revealed that when the outdoor air temperature fell below −7°C, the coefficient of performance (COP) of the air source heat pump units would deteriorate. Implementing intermittent heating during the second year can reduce heating energy consumption by 13.4 kWh/(m 2 ·a), resulting in 38.9% energy savings. These findings will serve as a valuable reference for the design and operation of heating systems in passive buildings in severely cold regions.