Field Experimental Study on Energy Performance of Aerogel Glazings with Hollow Silica: Preliminary Results in Mid-Season Conditions

In the last decades noticeable research efforts focused on aerogels, due to their thermal and acoustic insulation properties and potential applications in energy efficient translucent windows. In this work, thermal-energy and lighting performance of innovative double glazing units is evaluated through in-field experimental campaigns. Two identical rooms (Test and Reference) and a weather station are installed on the roof of a building in the Campus of Engineering (University of Perugia, Italy). An aerogel glazing system (AGS), consisted of aerogel granules mixed with opaque hollow silica in the interspace of a double glazing, is mounted in the window frame of the Test Room, whereas a standard double glazing system (SGS) with air in interspace is mounted in the Reference Room. The main quantities that influence the thermo-hygrometric and lighting conditions are monitored; preliminary results (June 2018) show that the indoor air temperature in the Test Room, especially the peak values, is about 6–7 °C lower than the one in the Reference Room. This trend is due to the presence of silica dust, which contributes to the reduction of the solar factor. At the same time, the maximum illuminance values close to the window are about 5000–8000 lux with SGS and about 2000–2500 lux with AGS; the Useful Daylight Illuminance (UDI) calculated during the working hours (8 a.m–6 p.m.) shows for AGS values 57% higher than SGS, highlighting the aerogel ability to diffuse light and to reduce glare.