A thermal performance parametric study of window type, orientation, size and shadowing effect

Abstract

Windows are one of the elements that greatly influence the performance of buildings, both in terms of thermal comfort and energy consumption for heating or cooling. It is therefore important to find an optimal design that balances their orientation, dimension and shadowing. This paper presents a method- ology for the parametric study of a window optimal dimension, based on the thermal performance of a reference room located in the climate region of Coimbra, Portugal. First, the parameters of opening type, orientation, and size are evaluated. During a second stage, the impact of using overhangs is assessed, with one of the most common window types in Portugal. The thermal assessment is carried out by cal- culating the degree-hours of discomfort using dynamic simulation. Results show that for this location, triple glazing has better performance than single and double glazing, especially for the north orientation. The worst opening orientation is northeast and northwest, independent of the window type. It is observ- able that optimum window dimension does not imply equal space cooling and heating needs. Results also demonstrate that overhangs do not significantly improve the room’s thermal performance but allow windows to have a wider interval of admissible sizes without compromising performance.