The influence of glazing systems on energy performance of non-residential buildings

Glass façades have an important role in buildings both for daylighting and thermal comfort. Many studies showed that health, comfort and productivity are improved due to access to natural light. Moreover the thermal and solar transmittance, the size and the orientation of the windows are very important in the energy use in buildings. The aim of the paper is to evaluate the influence of glass components in energy saving for non-residential buildings. A multifunctional building was investigated and a dynamic thermal model was implemented by means of EnergyPlus software. The energy demand was estimated in different climatic conditions and for different building orientations both for heating and cooling. The weather data of five Italian cities (Perugia, Rome, Palermo, Milan, Bolzano) were considered. In order to evaluate the impact of windows, different kind of glazings were selected: double-glazing with low-e coating and sunlight control double glass windows. Moreover, innovative glazing systems with silica aerogel (pane and granular) in interspace were investigated as a solution for energy saving in buildings. Finally, also the effects of blind systems on the façades were evaluated. Results showed that not only the thermal transmittance but also the solar transmittance of glazing has a large effect on thermal comfort and energy demand, depending on the chosen locality. The dynamic building models implemented in EnergyPlus software are very powerful tools and could allow to select for each scenario appropriate fenestration types, thanks to an accurate balance between energy consumption, thermal comfort and daylighting needs.