Researchers from the University of Kassel in Germany created a smart glass that could be the future of building efficiency.
Buildings are responsible for 40% of primary energy consumption and 36% of total carbon dioxide (CO2) emissions. Substituting inefficient glazing areas of buildings with energy-efficient smart glazing windows has the potential to decrease energy consumption from lighting and temperature control.
SEM micrograph of vertically standing, flat micromirror array with an inset of magnified area. Source: Hillmer et al.
Smart glazing is made of millions of micromirrors that reflect sunlight according to user actions, sun position, day time and seasons. Smart mirrors can create personalized light steering in buildings.
Micromirror arrays are invulnerable to wind, window cleaning and weather conditions. These arrays are placed in the space between window panes and are filled with noble gas, like argon or krypton.
Smart glazing provides free solar heat in winter and prevents overheating in the summer. It enables healthy natural daylight, huge energy savings, CO2 reduction and reduces 10% of the steel and concrete used in high-rise buildings.
Artificial lighting has health and well-being consequences. It is linked to lack of concentration, high susceptibility to illness, disturbed biorhythms and sleeplessness. Smart glass would reduce the reliance on artificial lighting by optimizing the natural daylight entering a room.
Current smart glazings are optimized for winter or summer, and they cannot ensure energy-saving performance all year. There is a need for smart and automated technology that can react to local climate, uses available sunlight and regulated light and temperature and saving substantial energy.
The team’s micro-opto-electro-mechanical system-based micromirror arrays are integrated inside insulation glazing and operated by an electronic control system. The mirror orientation is controlled by the voltage between the respective electrodes. Motion sensors in a room detect the number of people, their position and movement around the room.
The new smart glass was observed to have a higher actuation speed in sub-ms range and incur 40 times lower power consumption than electrochromic or liquid crystal concepts due to its color neutrality and reflective instead of absorptive properties. Rapid aging tests of the micromirror structure were performed to study the smart glass’s reliability, sustainability robustness and the long lifetimes of the arrays.
The study was published in the Journal of Optical Microsystems.
