The invention of electrochromic glass has facilitated the function of light adjustments for windows and spectacles, and now scientists have discovered that electrochromic materials can also be applied on building exteriors, which help with the heating and cooling of buildings, as well as reduce energy consumption for haters and air-conditioners.

Electrochromism refers to reversible color changes caused from alterations in material structures owing to changes in the electric field. Despite slight differences in operation modes, the structure of electrochromic equipment is usually formed with two transparent and conductive glass (electrodes), with an electrochromic solution in between, which bears similarities to the new electrochromic structure developed by the Duke University.

The electro layer of the new material is formed with graphene, and each unit of electrode is deposited with a layer of gold to increase conductivity, while the center of graphene also contains electrolytes mixed with metal nanoparticles, with the bottom layer of the material being a reflective substance (also regarded as a mirror).

The nanoparticles within the electrolytes would centralize at the top when current pass through, and the darkened electrolytes are able to absorb light and near infrared light, which effectively strengthens the heating systems of buildings. On the contrary, the nanoparticles of electrolytes, upon dispersion, would turn transparent and reveal the mirror to reflect sunlight that will reduce the level of heat entering the building.

 (Source: Duke University)

However, it is worth pointing out that the reflecting layer of the new material is not transparent, and cannot be used as a window like other electrochromic materials. Po-Chun Hsu, Professor of Duke Mechanical Engineering and Materials Science, believes that this technology can be applied on the exterior and elevation of buildings to passively provide heating and cooling effects to the house, which further lowers the energy consumption of heating, ventilation, and air conditioning (HVAC). For the US, the application is able to reduce nearly 20% of energy consumption for buildings.

Scientists are carrying on with the optimization of the material, and hope to increase the cycle between transparency and color changes, which is merely 24 times right now.

 (Cover photo source: pixabay)