Smart windows

Smart glass or switchable glass (also smart windows or switchable windows in those applications) is glass or glazing whose light transmission properties are altered when voltage, light or heat is applied. Generally, the glass changes from translucent to transparent, changing from blocking some (or all) wavelengths of light to letting light pass through.

Smart glass technologies include electrochromic, , thermochromic, suspended particle, micro-blind and polymer dispersed liquid crystal devices.

When installed in the envelope of buildings, smart glass creates climate adaptive building shells, with the ability to save costs for heating, air-conditioning and lighting and avoid the cost of installing and maintaining motorized light screens or blinds or curtains. Blackout smart glass blocks 99.4% of ultraviolet light, reducing fabric fading; for SPD-type smart glass, this is achieved in conjunction with low emissivity coatings.

Critical aspects of smart glass include material costs, installation costs, electricity costs and durability, as well as functional features such as the speed of control, possibilities for dimming, and the degree of transparency.

In suspended particle devices (SPDs), a thin film laminate of rod-like nano-scale particles is suspended in a liquid and placed between two pieces of glass or plastic, or attached to one layer. When no voltage is applied, the suspended particles are randomly organized, thus blocking and absorbing light. When voltage is applied, the suspended particles align and let light pass. Varying the voltage of the film varies the orientation of the suspended particles, thereby regulating the tint of the glazing and the amount of light transmitted.

SPDs can be manually or automatically "tuned" to precisely control the amount of light, glare and heat passing through, reducing the need for air conditioning during the summer months and heating during winter. Smart glass can be controlled through a variety of mediums, such as automatic photosensors and motion detectors, smartphone applications, integration with intelligent building and vehicle systems, knobs or light switches.

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Wikipedia