Improvements in glazing technologies to reduce building heat losses

This paper offers a review of the existing and emerging glazing technologies for windows. Windows account for up to 60% of the heat losses in buildings. The commercially available window systems on the market are double glazing, triple glazing, suspended films, vacuum glazing and smart glazing systems. Double glazing window systems can rarely meet the new energy standards while the other systems are expensive and not always reliable. Often, they require use of low-e coatings and inert gases which substantially increase cost of production. Recently, new glazing systems have been explored with the focus on window cavity filling and the novel combinations of materials in multiple cavities. Aerogel and PCM glazing systems represent the first segment of this research. While offering better U-values, such systems still have disadvantages such as material fragility (in case of aerogel), visibility (in case of PCM) and some other relevant parameters. Novel glazing designs such as solar pond and air sandwich also allow increasing thermal performance of the systems, but their applications are still in their infancy. PV systems represent a very promising direction in this regard. They are based on combining the existing proven technologies, and while showing higher U-values than other advanced glazing systems, they generate electricity to at least partially offset energy spending on heating and cooling. Optimisation of PV glazing system parameters is considered one of the major factors that could make them a product of choice in the nearby future.