Electrochromic glass reduces glare and thermal losses while still allowing the transmittance of visible light. The technology incorporates two nanometer-thin foils—one an electrochromic conductor often comprised of Indium Tin Oxide (TiO) and the other an ion storage layer—that have well defined porosities. Sandwiched between these nano-foils is a transparent electrolyte. All of this is sandwiched between a set of transparent electrodes, which are then emplaced between sheets of glass. When a low voltage is applied to the electrodes, a charge is created between the electrochromic and ion storage layers, effectively changing the optical characteristics of the glass.
The technology is analogous to a thin film battery in its mechanics. The nanomaterials used in the film are deposited onto the glass through a process called sputter deposition, the same process used to make low-e glass. Electrochromic glass is already currently available on market and is relatively affordable. Manufacturers like Sage Glass make electrochromic glass in multiple sizes and large quantities. When incorporated into building automation systems, electrochromic glass can reduce the lighting and heating/cooling load of a building. The integration of electrochromic windows into a large building envelope can save up to 50% of the primary energy used for air conditioning.
- . Progress in chromogenics: New results for electrochromic and thermochromic materials and devices. Solar Energy Materials and Solar Cells. 2009 ;93(12):2032 - 2039.
This product offers the potential for more efficient building design and operation through increasing efficiencies in the heating and cooling of the built environment.
The risks associated with this technology are very few since sputter deposition is a common, well developed process. The largest risks are release of emissions and chemicals into the environment. If the manufacturing facility has taken adequate precautions concerning filtering and emissions controls, these risks are minimal. The nanomaterials used are foils rather than particles, and are incorporated into the glass so they are much less harmful to the environment during the disposal process. These foils do not break down into free aspect nanoparticles, greatly minimizing any negative ecological or human health risks.