Natural Airflow in a Reversible Double-Glass Window with Reflective Film for Building Applications

Abstract

This investigation is focused on assessing the thermal performance of a ventilated double-glass reversible window with reflective film for building applications. The window is composed of two glass sheets separated by a gap forming a channel. One glass sheet faces the external environment while the second glass sheet faces the internal environment. A solar reflective film is attached on the internal surface of the first glass sheet for hot climates or attached on the internal surface of the second glass sheet for cold climates. A home-built numerical code is developed, using the finite volume method for the discretization of conservative equations, and validated against available numerical and experimental results. The simulations were done hourly for representative days of the summer and winter seasons. Three possibilities were examined in this study: a ventilated double-glass window without a reflective film, a ventilated double-glass window with a reflective film for hot climates, and a ventilated double-glass window with a reflective film for cold climates. Based on the results, for the hot climates, the use of a reflective film is highly recommended because the ventilated double-glass window with a reflective film was able to reduce 57% of the energy gain in comparison with the same window without a reflective film. For cold climates, the ventilated double-glass window without a film is better than the same window with a reflective film.