Numerical analysis of the thermal behaviour of ventilated glazed facades in Mediterranean climates. Part I: development and validation of a numerical model

Ventilated glazed facades are formed by two layers of different materials, opaque or transparent, that are separated by an air channel, used to collect or evacuate the solar radiation that is absorbed by the facade. For architectonic reasons, the outer layer is usually made entirely of glass, while the indoor layer may be partially opaque. This allows direct solar gains to be reduced and increases the thermal inertia of the building. This paper is a presentation of a code for the numerical simulation of ventilated and conventional facades. It is based on time-accurate, one-dimensional discretizations for the channel and the different solid zones, and allows heat fluxes and temperature distributions in the facade to be obtained over the course of one year. The numerical code allows advanced elements to be integrated into the facade, such as phase change materials, selective surfaces and improved glasses. The code has been validated by comparing it with analytical solutions where possible, with reference situations and with experimental measurements obtained in real-site test facilities in different climatic conditions. The numerical code is a useful tool for optimising the design of facades so as to take advantage of different materials, orientations, geometries and to address different climatic conditions. (C) 2003 Elsevier Ltd. All rights reserved.