Heat transfer analysis of vacuum insulated windows compared to traditional fenestration technologies: A thermal model analysis

Evacuated glazing is novel window technology that have reported excellent heat transfer properties in recent years (as low as 0.8W/m²K) when compared to single-layered solutions. Since window energy consumption accounts for up to 40% the total electricity consumed by buildings, the need of highly insulated solutions for windows is a priority particularly for recent international building codes. This paper aims to represent a comprehensive approach to multi-layered technologies (double, triple, vacuum and photovoltaic vacuum glazing) under an office use environment. These simulations utilised a variety of climatic conditions (tropical, arid, temperate, continental and tundra) for assessing the glazing performance. EnergyPlus™ heat balance model was utilised for calculating the indoor to outdoor temperature performance, heat gain and loss of energy, heat transfer, visible transmittance and radiation impact. Photovoltaic vacuum window reduced the summertime temperatures in office buildings by 7.5°C in Las Vegas, 6.25°C in London and 5.39°C in Beijing). For extreme temperature mitigation, photovoltaic vacuum glazing PV resulted the best option for locations in Kuala Lumpur, Las Vegas, London and Beijing. Vacuum glazing VG on the contrary was best suited for extreme cold conditions as those presented in Kuujuaq Canada. For energy saving assessment, triple glazing TG reduced heat gain rates by -41.8% in Kuala Lumpur, -38.5% in Las Vegas, -37.2% in London, -38.9% in Beijing and -33.2% in Kuujuaq when compared against SG. Reduction on heat losses can be accounted by -83.8%, -83.7%, -82.9%%, -81.6% and -82.3% in a similar array. Vacuum insulated window demonstrated its ability to reduce heat transfer compared to traditional fenestration technologies, undoubtedly a more extensive use of this technology is forecasted in the near future when improvements in the manufacturing process make this technology to be widely available.