Simulation Model for Some Types of Double Envelope Elements

It has been found that, among the tools and methods available for the energy calculation of double envelope elements, there are some debatable aspects such as: the selection of correlations for calculating the convective heat transfer coefficient and the procedure for calculating the temperature of the air layer. In addition, the validation of some models only refers to specific cases or no information is available whether or not a validation has been performed. This paper presents a transient model for the energy calculation of double envelope elements, using correlations for the calculations of the convective heat transfer coefficients specifically developed for this type of element. For validation, information reported by other authors has been used. This model can be applied to those elements with an opaque or semitransparent exterior envelope (usually glazing) of negligible thermal inertia, an air layer thickness less than 0.1 m, and an opaque interior envelope (usually a massive wall) with or without thermal inertia. This model is suitable for short time step calculations.