Application of Vacuum Insulated Glass in Construction Field

With the introduction of green building related national policies, building energy efficiency has received more and more attention. Research data show that building energy consumption has accounted for one-third of the total energy consumption of the society. While 50% of the building energy consumption is lost through windows and doors, 80% of the loss can be attributed to the glass. In the meantime, the waste water, gas, and residue produced by energy production impose great risk to the construction of the ecological civilization and human health. Under such a severe situation, it is imperative to speed up the development of green energy-saving building materials such as vacuum insulated glass.

By definition, vacuum insulated glass is an item consisting of two or more panes of sealed up glass with the air in the tiny space between the panes removed to achieve a vacuum state. As a new high performance energy-saving glass product with remarkable energy saving effect, vacuum insulated glass has the advantages of low heat transfer coefficient, high sound insulation performance, and light structure. It is an ideal energy efficient and environmentally friendly material, capable of significantly improving the performance indicators such as building energy saving standard and indoor environment to raise the overall building quality. A team of one hundred R&D researchers from LandGlass launched the tempered vacuum insulated glass LandVac® after eight years of endeavor. It offers seven major advantages, including the superior thermal and sound insulation performance, especially when compared with ordinary vacuum glass.

Energy saving green product

Thanks to the high vacuum chamber of LandVac that effectively blocks the thermal transmission, the thermal insulation performance of LandVac is 2-4 times better than laminated glass and 6-10 times than single pane glass. The properties of this product meet all international thermal transmittance requirements on windows and doors for passive houses. In addition to significantly reducing the energy consumption in the construction sector and the emission of waste water, waste gas, and waste residue, it can mitigate certain “A/C diseases” symptoms associated with staying in an air conditioned environment for extended period of time such as dizziness and upper respiratory tract infection.

Effective noise reduction

Thanks to the high vacuum chamber of LandVac that effectively blocks the sound transmission, the sound isolation performance is far better than the laminated glass. It has remarkable soundproof effect against high penetrative mid-low frequency noises such as traffic and construction noises. With the increasing density of urban buildings, traffic flow, and shopping malls, noise has become one of the most severe pollution sources. The emergence of LandVac has a far-reaching significance for restoring a peaceful and harmonious living environment.

High safety

Surface stress and granularity of LandVac meet tempered glass standards. It has passed several key safety tests including wind resistance test and impact test. Each piece of LandVac can withstand the pressure of a 1.7 m tall sand column, equivalent to even-distributed load of 40 adults with an average body weight of 70 kg standing on one square meter of LandVac. By adopting low temperature flexible sealing technology, LandVac completely retains the high strength, impact resistance, and other safety attributes of tempered glass. In case the glass breaks, it shatters into small and less harmful honeycomb shaped particles.

As one of the new generation energy saving materials promoted by the nation, LandVac® vacuum insulated glass not only has realized commercial production, but also has been successfully listed in the “Catalog of the Recommended Products for Passive Low-energy Buildings” of MOHURD. Thanks to its outstanding advantages in thermal and sound insulation performance, LandVac® is well-received in the passive house project in Urumqi, Xinjiang. In the context of global promotion of green buildings, LandVac has earned its reputation in the low energy consumption passive house projects with its unparalleled energy properties. It certainly means a wider market prospect for LandVac. In addition, vacuum insulated glass has also a board range of applications in many areas including green household appliances, transportation, and military development. We are confident that LandVac will make greater contributions to the global efforts in the fields of energy saving, green and environmental protection in the future.

https://www.landvac.net/

What is Vacuum Insulated Glass?

Vacuum insulated glass is made of two or more panes of glass separated by spacers, where in the space between panes of glass is evacuated and edges vacuum-tight sealed. Kept between two panes is a gap of 0.1~0.3mm. To ensure the glass can withstand the atmosphere pressure under vacuum, micro spacers are placed between panes to provide support.

Vacuum insulated glass is developed based on the principle of Dewar flask (i.e. vacuum flask), where the vacuum layer is used to reduce gas conduction and convection to achieve features such as heat insulation, anti-condensation and frostproof, noise reduction, etc. Vacuum insulated glass is a hi-tech, environmental friendly glass product that promises more energy saving. The production involves vacuum technology, materials science, mechanical and automation technology, and precision measurement technology. It has wide range of applications in windows and doors for buildings, vehicles, and vessels, thermal insulation cases (for example: showcase, refrigerated storage), and other devices that require the use of transparent, heat insulated materials. 

From: https://www.landvac.net/

Applications of Vacuum

Vacuum Applications in Our Daily Life

Since the discovery of vacuum, from the vacuum flask in early days, to the vacuum pasteurization, or CRT tube manufacturing, or vacuum packaging today, vacuum technology has had a very wide application area and become an indispensable part of our daily lives. 

Vacuum Applications in Aerospace Industry

The significance of vacuum technology to aerospace industry is the simulation of outer space environment as launch vehicles, satellites, manned spacecrafts, space stations, space probes, space shuttles or other space vehicles are all operating in natural vacuum of the universe during the flight. 

As such, in addition to directly dealing with space vacuum environment, they are also exposed to solar radiation, various charged particles, and extreme temperature changes. These external factors could cause change or damage to the material properties, malfunction of sensitive instruments, endangering the proper operation of the vehicle and the safety of the astronauts. Therefore, it is necessary to establish ground experimental devices and facilities that can simulate space environment in universe. The safety of the spacecrafts and astronauts can only be properly ensured when the vehicle passes all the ground simulation tests and is successfully debugged under the simulated working conditions and characteristics of space environment to reduce potential risks in the flight. For these purposes, many simulation facilities of different kinds have been built on the ground.

From:https://www.landvac.net/

Early History of Vacuum Technology

In 1643, an Italian physicist Torricelli proved the presence of vacuum and atmosphere pressure in natural space. He created a long glass tube, sealed at the top, filled it with mercury, and set it vertically into a basin of mercury. The column of mercury fell to about 76 cm above the surface level of the mercury outside the tube. Torricelli believed that it left vacuum in the glass tube above the mercury. The 76 cm mercury column height is determined by the atmosphere pressure.

In 1650, the first piston vacuum pump was invented by Otto von Guericke of Germany.

In 1654, he conducted his famous Magdeburg hemispheres experiment in Magdeburg: he used the vacuum pump to suck the air out from inside the two attached hemispheres around 14 inches (35.5 cm) in diameter and demonstrated that two teams of eight horses pulled in opposite directions could not separate the two copper hemispheres. The experiment once more proved the presence of atmosphere in the space with tremendous pressure. To commemorate Torricelli in scientific discoveries and contributions, the torr, a conventional unit of pressure used in vacuum measurements, is named after him.

From:https://www.landvac.net/

Units in Vacuum Measurements

The most commonly used unit in vacuum measurements is Pa. 1Pa is equal to 1N/m2. The unit used in technical atmosphere is Bar. 1Bar=1kgf/cm2. The unit now used less often is torr. 1Torr is defined as 1/760atm.

	Atm	Pa	Bar	Torr
ATM	1	1.013×105	1.013	760
PA	0.987×10-5	1	1×10-5	7.5×10-3
Bar	0.987	1×105	1	750
Torr	1.32×10-3	133	1.33×10-3	1

While P is the symbol for pressure, the measuring unit is “pascal” or “Pa” in short. Pascal is a basic measuring unit for pressure in the international system of units, named after French physicist Blaise Pascal.

The physical significance of 1Pa: It is defined as 1N per square meter. The air density varies above the Earth’s surface where density near the ground is greater and decreases as altitude increases. While atmosphere pressure is caused by air gravity, the column in the tube falls lower at higher altitude with less air density. Higher the altitude is, less atmosphere pressure it gets. Within elevation of 3000m, the atmosphere pressure decreases by 100Pa per every 10m of rising height. Within elevation of 2000m, the atmosphere pressure decreases by 1mmHg per every 12m of rising height.

From:https://www.landvac.net/

What is Vacuum?

A vacuum is a physical space with no or very little gas molecules and atoms in it. It is a field space where only a variety of energy particles exist. In applied physics and technical applications, vacuum refers to a given space with pressure of the gas state lower than a standard atmospheric pressure. While a perfect vacuum is a totally empty space with no gas, relative vacuum is a gaseous state measured based on the standard atmosphere pressure. 

FROM：https://www.landvac.net/

Classification of Vacuum Level

he so-called “vacuum” refers to a gaseous state where the pressure in a given space is less than 101325 Pascal (i.e. a standard atmospheric pressure around 101KPa).

The standard or unit of vacuum measurement is called vacuum level. In the international general standards and China’s current standard in force, the most commonly used unit in vacuum measurements is Pascal ( Pa.). 1 Pa is equal to 1N/㎡. The unit used in technical atmosphere is Bar.1Bar=1kgf/cm2. The unit now used less often is torr. 1Torr is defined as 1/760atm.

International general classification of vacuum levels

The international standard usually divides the vacuum into four levels: low vacuum, medium vacuum, high vacuum, and ultra-high vacuum. In absence of strict criteria, the vacuum levels are roughly divided as follows:

Low Vacuum Level   （< 105~102Pa）  —— The pressure difference obtained by low vacuum is used to clamp, lift and transport materials, as well as to vacuum and filtrate (e.g. vacuum cleaner, vacuum suction cups, etc.)

Medium Vacuum Level （< 102~10-1Pa） —— Medium vacuum is generally used to remove the gas or moisture that is retained and dissolved in the material, as well as for vacuum heat insulation and isolation (e.g. food vacuum freezing, vacuum drying, vacuum packaging, etc.)

High Vacuum Level  （< 10-1~10-5Pa） ——vacuum smelting, vacuum coating, and manufacturing of vacuum devices can be done by using the characteristics of low density of residual gas and weak chemical action of any substance in high vacuum. A typical product is vacuum insulated glass. Vacuum insulated glass refers to the glass consisting of two or more pieces of flat glass with micro supporting spacers inside and edges sealed to create vacuum chamber in between. In principle, the vacuum level inside the vacuum insulated glass is lower than 10-1pa, so that the factors such as heat transfer by gas and sound transmission can be ignored.

Ultra-high Vacuum Level  （< 10-5Pa） —— In the ultra-high vacuum state, there is almost no atoms or molecules. It can be used for simulation of a space environment, as well as researches on surface physics and surface chemistry, etc. 

From：https://www.landvac.net/