Numerical prediction of indoor air humidity and its effect on indoor environment

A numerical model to assess the thermal comfort taking into account the indoor air moisture and its transport by the airflow within an enclosure is described. The approach is essentially based on the computational fluid dynamics technique, using a revised k– turbulence model, the “realisable” k– model. To obtain a field description in terms of indoor air water vapour ratio, a convection–diffusion conservation equation of vapour mass fraction is added to the basic flow equations. The model is applied to the prediction of the indoor environment in a mechanically ventilated test room. Therefore, direct experimental–numerical comparisons with regard to thermal comfort indexes are given. Based on the results achieved, the numerical model proves a good potential to correctly estimate the indoor environment in steady and homogenous thermal conditions. As a result, the model can be particularly useful in studies dealing with thermal comfort predictions or in situations where an exact distribution of indoor air moisture is required.