Application of super-insulating translucent silica aerogel glazing system on commercial building envelope of humid subtropical climates – Impact on space cooling load

Solar radiation through glazing area is one major source of the space cooling load in subtropical cooling-dominant climates. Application of energy-efficient glazing system can significantly reduce the energy consumption of air-conditioning systems in summer, thus has become a hot research topic. In this paper, a super-insulating glazing system was studied, which was formed by two layers of conventional single clear glass panes and a layer of silica aerogel filled in between. Several glazing samples were prepared. The thermal and optical parameters were measured. An annual HVAC (heating, ventilation and air conditioning) system energy analysis was also conducted based on the space cooling load simulation. The result indicated that in humid subtropical climates like Hong Kong, the application of silica aerogel glazing system can reduce the annual space cooling load by around 4% in a typical commercial building. With respect to the envelope heat gain, the reduction could be around 60%. It was also found that the silica aerogel glazing system performed better if the internal heat source in a building took a small proportion in the total space cooling load.