Energy assessment of gasochromic smart windows for a high-rise apartment block in a temperate climate

Abstract

A significant proportion of the UK’s carbon emissions currently derive from burning natural gas for domestic heating. Developing and implementing methods to reduce heating demand is therefore crucial for the UK in decarbonising its economy – and here smart windows provide a significant opportunity: the ability to alter a window’s optical properties provides control over the heating impact of the sun on a building. This report focuses on the gasochromic smart window: whereby introduction of hydrogen within the glazing gap tints the window and oxygen bleaches the window. Gasochromic windows have never been simulated in the UK, with the aim of this report to assess the potential for gasochromic windows in Birmingham, UK. This aim was assessed through three objectives: comparing performance against other glazing types, optimising switching criteria, and a comparison against location effects. The results showed that gasochromic windows were the most effective at reducing the heating, ventilation and cooling (HVAC) load, exhibiting a 20.2 % decrease in load compared to a standard double-glazed window. There was a 4.9 % benefit of optimising the switching criterion compared to having the window permanently in its bleached state. Over a full rotation of the building, there was a 5.4 % range in the HVAC load. Whilst the performance of the window is promising, the difficulty of retrofitting and the UK’s small hydrogen economy renders gasochromic windows unviable at present and in the near future. However, the technology could be viable in other countries more invested in the hydrogen economy and with higher housebuilding rates.