Humidity distribution in high-occupancy indoor micro-climates

Abstract

The general consensus among academics is that the spatio-temporal humidity distribution is more or less uniform in an indoor space. This has, for the large part, not yet been proven by an academic study; subsequently, this paper aims to demonstrate that this is not always true. The paper makes use of a validated transient CFD model, which uses the Low Reynolds Number k-ϵ turbulence model. The model simulates people in a room at a constant skin temperature and emitting a constant source of humidity using source terms in the species equation. The model is eventually used to predict the implications of having a high source of humidity, in the form of occupancy, on the micro-climate’s spatio-temporal humidity distribution. The results for the high-occupancy case show that different locations experience various amounts of humid air, with a 31% difference between the lowest and highest locations. The amount of water vapor in each person’s proximity is deemed to be highly dependent on the flow of the inlet jet, with the people farthest from the jet having an overall less mass of water vapor in their proximity over the two-hour experimental period. This paper has concluded that there are, in fact, cases where the humidity non-uniformity inside an interior environment becomes substantial in situations of high occupancy. The results of this paper may be useful to improve the design of HVAC systems.