| The moisture distribution within a space and the degree to which moisture movement can be modelled
using tracer gas techniques and the Computational Fluid Dynamics (CFD) model FtoVent is examined.
The validity of these methods to study moisture migration is studied experimentally in an environmental
two zone test chamber. It is found that molecular diffusion plays a very small role in airborne moisture
movement. Thus, airborne moisture migration is primarily affected by air movement. The major
influences are the shape of the buoyant plume and the position of air supply and extract in relation to
the moisture source location.
1 Introduction
Condensation is a major problem in a large number of dwellings in the UK [ 1] and other cold climates.
The reduction of ventilation levels for energy conservation coupled with low internal temperatures in
some parts of a dwelling have increased condensation problems in many cases. The importance of
ventilation in reducing condensation risks and the importance of the local removal of moisture at source
have been long recognized and recently implemented in the current Building Regulations [2].
The work reported in this article forms part of a broader research project dealing with the study of
airbome moisture movement and its effects on condensation risks in dwellings. The aim of the project
is twofold; a) to produce a moisture balance algorithm for the use in an existing model [3] which
predicts the risks of mould growth in dwellings and b) to advice on extract fan capacity. | 