Smart thermochromic glazing for energy saving window applications

Thermochromic laminated glazing (TLG) aids in reducing the energy needs of a building and providing indoor comfort. The polymeric interlayer of TLG is doped with transition metal (Fe, Cr, W, etc.) complexes, which change their coordination and the transmission or color of TLG under the influence of light and heat fluxes. At present we have conversions from light gray or brown to dark gray or brown and from rosy or yellow to blue or green at our disposal. TLG is able to sense changes in the light and adjust accordingly. It can block out the sunlight during the brightest parts of the day or capitalize on the available light during overcast days. As evaluated on the basis of tests, TLG has a good UV stability. It offers practical benefits of a low cost and easy fabrication. No electrical or any other driving power is needed to operate TLG. The energy modeling of the heat transfer in ventilated facades showed that TLG can provide a 15-30% decrease of the building energy consumption during the winter heating time in the climatic conditions of some regions in Russia. During the summer season the reduction of the solar energy gain reaches 30-40%; this is enough to give up air- cooling systems altogether.