The impact of refurbished windows on Portuguese old school buildings

Abstract

ABSTRACTThis paper presents results of a study investigating ventilation mode, solar heat gain and daylight performance via vertical fenestration of a common school building in Portugal. In recent years, there has been a growing awareness in energy-efficient building design and operation of the building stock. The windows are usually the first component to be replaced by new and more efficient ones. Dynamic envelope/window systems may optimize the performance of the building when taking into account airing, solar heat gain rejection/acceptance and daylight admission. Higher thermal resistance glazing implies a reduction of solar transmittance. A typical school building located in Covilhã, Portugal was used for the study. Three different conventional windows were used for comparison: a single pane as found in the building, a double-pane to increase the thermal resistance and a double-pane with daylighting controls. Different simulation tools were used during this study. To be comparable with other studies, several ratios were present, namely the window/wall, the glazing/wall ratios, the window/floor and the glazing/floor ratios as well as the window opening area. This paper presents the obtained airflow and solar gains on both the heating and cooling season as well as the level of daylight for both overcast and non-overcast skies. The findings are essential for the assessment of passive building energy-saving techniques on a hypothetical building refurbishment by replacing old windows. However, specific adaptive actions to improve indoor environmental quality are also needed.