Thermal performance study of multiple thermal insulating glazings with polycarbonate films as interval layers

Abstract

With the development of global economy, the proportion of energy consumption in buildings is increasing to approximately 40% total energy consumption. The glazed window system, which is the weakest part in the building envelopes, remarkably contributes to energy loss. Scholars and manufacturers are constantly working to improve the thermal properties of glass, such as Low-E glass, aerogel glass, vacuum glass, and so on. However, the advanced glazing either shades the sunlight in winter, or is too expensive to be widely used. In this paper, polycarbonate films with high transparency are used as the interval layers of double glazing, which not only have better thermal properties and visible light transmittance in winter, but also are less expensive to be used. The structures and thermal properties of multiple thermal insulating glazing with polycarbonate films (MTIGP) are systematically investigated. The U-values of MTIGP can be achieved from 1.5 to 2.0 W/m2·K with high transmittance of visible light (Tvis, 60–70%), when compared with a typical Low-E double glazing system (U-value, around 2.0 W/m2·K; TVis, around 60%), even lower when argon (Ar) or krypton (Kr) is used instead of air. The Solar Heat Gain Coefficient (SHGC) of MTIGP is higher than that of a typical Low-E double glazing system, which means more sunlight transmitting into the glazing system in winter to keep the rooms warmer. MTIGP and double silver Low-E pane are simulated with EnergyPlus, the results shows that energy consumption of MTIGP is better than that of double silver Low-E pane. The developed glazing system is expected to be used in severe cold and cold climate zones to improve thermal insulation and sunlight transmittance to reduce energy consumption.