Smart glass keeps you warm in winter and cool in summer

Tie Jun

In summer, the outdoor temperature rises and the light intensifies, and the indoor light and temperature will also change. People must not Instead of turning on the air conditioner or closing the curtains, those who drive need to prepare a reflective panel in the car to block direct sunlight. Nowadays, smart glass successfully developed by Professor Yang Huai of the University of Science and Technology Beijing can control the transmittance of visible light and infrared rays according to changes in outdoor temperature. This kind of smart glass will greatly reduce the use of air conditioners and curtains, making it very convenient. In our life, you will feel the warmth in winter and coolness in summer brought by technology.

What is smart glass? Simply put, glass whose optical properties such as transmittance, reflectivity or color can be adjusted by temperature, electric field, and magnetic field is called smart glass. Smart glass is made by filling the middle of double-layer transparent glass with a polymer composite material. The molecular orientation of the polymer composite material changes with temperature or applied electric field strength, so the smart glass will change according to changes in outdoor temperature or applied electric field strength. Change its own light and infrared transmittance to achieve the effect of regulating indoor temperature. Smart glass is divided into the following three categories according to its principles and methods:

Temperature-controlled smart glass

This kind of glass can be transparent in summer and winter, but can block the temperature in summer. Temperature-controlled smart glass that cuts off infrared light but allows infrared light to pass through in winter. Using this kind of smart glass as the door and window glass of a building or car, when the temperature exceeds a certain temperature in summer, the thermal radiation of the sun's infrared light can be shielded, so it cannot enter the building or car without affecting the building or car. In the absence of visible light, the interior of a building or car becomes cooler. This glass therefore has the same insulating properties as Low-E glass in the summer. In winter, the thermal radiation of the sun's infrared light can enter the building or car, making the building or car warmer without affecting the visible light in the building or car. This overcomes the problem of using traditional low-emissivity Low-E glass as the door and window glass of buildings or cars. In winter, just like in summer, the thermal radiation energy of the sun's infrared light is also shielded, which is not conducive to the heating of buildings or cars in winter. shortcoming.

This kind of glass can also be transparent only in winter. The light transmittance decreases as the temperature increases. In summer, when the temperature exceeds a certain temperature, it becomes almost opaque because of its strong light scattering state. The thermal radiation of the sun can be shielded and cannot be irradiated into the building or car. After the temperature drops, it returns to the transparent state.

Electronically controlled smart glass

The first is light scattering state (off) - transparent state (on) electronically controlled smart glass.

Without applying an electric field to the smart glass, the smart glass exhibits strong light scattering. When an electric field is applied to the smart glass, the smart glass becomes transparent. After the electric field is turned off, the smart glass returns to a strong light scattering state.

The second is transparent state (off) - light scattering state (on) electronically controlled smart glass.

When no electric field is applied to the smart glass, the smart glass is transparent. When an electric field is applied to the smart glass, the smart glass shows strong light scattering. After the electric field is turned off, the smart glass becomes transparent. The glass is transparent again.

The third is memory electronically controlled smart glass.

When a low-frequency electric field is applied to the smart glass, the smart glass is in a strong light scattering state. After the electric field is turned off, the light scattering state is maintained and remembered; when a high-frequency electric field is applied to the smart glass , the glass is in a transparent state, and the transparent state is maintained and remembered after the electric field is turned off.

Temperature-controlled and electronically controlled composite-controlled smart glass

The light transmittance of this smart glass decreases as the temperature increases. In winter, this smart glass is transparent when no external electric field is applied. When a high-frequency electric field is applied to the smart glass, it exhibits a strong light scattering state. After the electric field is turned off, the light scattering state is maintained and remembered. When a low-frequency electric field is applied to the smart glass, the glass becomes transparent. After the electric field is turned off, the transparent state is maintained and remembered. In summer, when the temperature exceeds a certain temperature, the smart glass will be in a light scattering state without applying an external electric field. But when a low-frequency electric field is applied to it, the smart glass becomes transparent. After the electric field is turned off, it returns to the light-scattering state.

A statistic shows that in office buildings that use air conditioners, about 15% of the heat comes from sunlight coming in from the windows. If this kind of smart glass is used in the office building, it can filter It removes more than half of the heat from sunlight, thereby saving a lot of precious energy. According to reports, compared with smart glass products being developed and produced abroad, the smart glass developed by the University of Science and Technology Beijing has a driving voltage of only 5 to 8 volts, which is far lower than the 110 volts of similar Japanese products. It is more sensitive to temperature changes and can "real-time" "Monitoring" changes in external temperature, the cost is only 1/5 of that abroad. Recently, the University of Science and Technology Beijing and Beijing Weihao Company signed an agreement to cooperate in the production of smart glass for ordinary buildings, cars, office partitions, hotel rooms, shopping malls, etc., announcing the era of exclusive foreign ownership of this technology and market. Finish.