Comparison of winter air infiltration and its influences between large-space and normal-space buildings

Abstract

Air infiltration brings challenges to energy saving and indoor air quality in buildings. Previous studies about air infiltration mainly focused on normal-space buildings, while less attention has been paid to large-space buildings, which are currently widespread. This study uses theoretical models to compare winter air infiltration in the two categories of buildings. The most common situation of winter air infiltration in normal-space buildings is the outdoor air through envelope cracks; however, that in large-space buildings is actually some unintentional openings (i.e., normally-opened windows/skylights, exterior doors for entrance, etc.). The calculation results indicate no noticeable difference in the air change rate of winter air infiltration between the two categories of buildings, which is also supported by field measurement data from the literature. Then, this paper discusses the different challenges faced by the two categories of buildings with the influence of air infiltration. A smaller shape coefficient of a large-space building (0.07–0.27 m-1) results in a higher proportion of heating load by air infiltration than that of a normal-space building (0.20–0.80 m-1). Besides, a smaller occupant number per volume of indoor space of a large-space building (1.6 × 10−4 to 1.2 × 10−2 person/m3) makes it less likely to be severely affected by indoor-originated air pollutants (indicated by CO2 concentration) than that of a normal-space building (1.3 × 10−2 to 2.1 × 10−1 person/m3).