A new method to assess infiltration rates in large shopping centers

Large shopping centers integrate multiple functions within a single building, which typically results in high energy consumption. Building energy performance and indoor air quality are significantly dependent upon ventilation, which is influenced by uncontrolled air leakage (i.e. air infiltration) across the building exterior. In general, shopping centers in China are in a state of significant negative pressure due to the sub-optimal management of air conditioning operational systems. Therefore, an accurate estimation of the air infiltration rate is necessary to instruct operational management and to improve energy performance. Common infiltration rate testing methods often fail to continuously measure infiltration rates in large inner spaces for extended time periods. This paper presents a new methodology to assess the infiltration rate using the mass balance of particulate matters whose aerodynamic diameters are smaller than 2.5 μm (PM2.5). The deposition, generation and penetration of indoor PM2.5 are also considered. A field test is conducted in a large shopping center in Beijing (China), with the new method applied to assess the infiltration rate. The results are verified by the airflow mass balance throughout the entire building. Also, the methodology helps to determine the main sources of indoor PM2.5 as well as to instruct how indoor PM2.5 concentration can be effectively reduced.