low emissivity glasses and coated glasses manufacturers&suppliers

 

Low-e Glass VS Coated Glass

 Low emissivity glass is one of the coated glasses. Low emissivity glass is also called low E glass. The reflective color of Low-e is purple.

LOW-E Glass 

 

Low-E glass is a film system consisting of multiple layers of metal or other compounds coated on the glass surface. The coating layer is highly transmissive to visible light and highly reflective to mid and far-infrared rays: Excellent thermal properties 

 

The emissivity of ordinary float glass is as high as 0.84, but when coated with a silver-based low-emissivity film, the emissivity can be reduced to less than 0.1. 

 

If Low-E glass is used, the fuel consumed for heating can be significantly reduced due to the reduction of heat loss, thus reducing harmful emissions. Good optical properties 

 

Low-E glass has a high transmission ratio of visible light from sunlight, up to 80% or more, and a low reflection ratio, which makes its optical performance much better compared with traditional coated glass. From the outdoor view, the appearance is more transparent and clear, which ensures good lighting of the building and avoids the light pollution caused by light reflection from large glass curtain walls and hollow glass doors and windows in the past.   

 

Coated glass

 

Coated glass can be divided into the following categories according to the different characteristics of the product: heat-reflective glass, low-E glass (Low-E), conductive film glass, etc.

 

Heat-reflective glass is generally coated on the glass surface with one or more layers of metals such as chromium, titanium, or stainless steel or their compounds composed of thin films, so that the product is richly colored, has an appropriate transmittance for visible light, a high reflectivity for infrared light and a high absorption rate for ultraviolet light, therefore, also known as sunlight control glass, mainly used in buildings and glass curtain walls. 

 

low-emissivity glass is coated on the glass surface by a multi-layer silver, copper, or tin and other metals or their compounds composed of thin-film system, the product has high transmittance of visible light, a high reflectivity of infrared light, with good thermal insulation properties, mainly used in buildings and cars, ships and other vehicles, due to the poor strength of the film layer, is generally made into hollow glass use. 

 

Conductive film glass is coated with indium tin oxide and other conductive films on the surface of the glass, can be used for heating, defrosting, defogging and as liquid crystal displays, etc.


  
The strength of the absorption capacity of the glass is directly related to the effect of the glass on the blocking of far-infrared heat. Low emissivity of the glass is not easy to absorb external thermal radiation energy, and thus the glass through the conduction, radiation, convection of heat energy transmitted by less, low radiation glass is precisely to limit this part of the heat transfer.



The above two forms of heat transfer through the glass can be attributed to two ways: direct solar radiation through the heat transfer, convection conduction heat transfer. 

The total thermal power Q transferred through each square meter of glass can be expressed by the following formula. 


Q = 630Sc + U (T inside - T outside)  


Where 630 is the intensity of solar energy through 3mm transparent glass, (T inside - T outside) is the air temperature on both sides of the glass, are parameters related to the environment. 

 


SC and U are parameters inherent to the glass itself, and their meanings are as follows. 
SC --- the shading coefficient of the glass, the value range 0 to 1, which reflects the shading effect of the glass on the direct solar radiation. U - the heat transfer coefficient of the glass, which reflects the ability of the glass to conduct heat. 

 


It can be seen that the energy efficiency of the glass by the two parameters of U and SC can be completely determined 


  
The heat transfer characteristics and parameters of different glasses

 

1、Ordinary transparent glass 

The transmission range of transparent glass (soda-lime-silica glass) coincides with the solar radiation spectrum region, therefore, while transmitting visible light, the infrared heat energy in sunlight also passes through the glass in large quantities, while the heat energy in the 3~5μm mid-infrared band is absorbed in large quantities. 

 

2、Heat-reflective coated glass (sunlight control coating) 

Heat-reflective coated glass - metal or metal compound coating on the glass surface so that the glass is rich in color and has new light and thermal properties. Its main function is to reduce the shading coefficient SC of the glass and limit the direct transmission of solar radiation. The heat-reflective film layer has no significant reflection effect on the far-infrared, so there is no significant contribution to improve the U-value. 

 


In areas with the strong summer light, the heat-reflective glass has a very obvious thermal insulation effect and can effectively attenuate the solar thermal radiation entering the room. However, in sunless environments, such as night or rainy weather, its heat insulation effect is no different from that of white glass. From the viewpoint of energy-saving, it is not suitable for cold areas, because these areas need sunlight to enter the room for heating. The only purpose of using this glass in cold areas in the north is to pursue decorative effects.  

 

3、Low-E glass (low-emissivity coated glass)


Low-E glass - the surface of the glass is coated with low radiation material silver and metal oxide film so that the glass presents different colors. Its main role is to reduce the U-value of the glass, while selectively reducing the SC and improving the energy-saving characteristics of the glass in general. High-transmission Low-E glass, with a shading coefficient of Sc ≥ 0.5, has less attenuation of transmitted solar energy. This is extremely suitable for the healing-oriented northern areas, the winter solar wavelength radiation can enter the room through this type of Low-E glass, which is absorbed by indoor objects and becomes far-infrared heat radiation that cannot be transmitted through Low-E glass, and is restricted to the room together with the heat radiation emitted by indoor heating, thus saving the cost of heating.



Shading type Low-E glass, shading coefficient SC <0.5, more attenuation of the transmitted solar energy. This is extremely suitable for the southern region where air conditioning causes cooling, which can limit the solar energy into the room to the maximum extent in summer and block the far-infrared heat radiation from outdoors, thus saving the cost of air conditioning usage. 

 

Different varieties of Low-E glass are suitable for different climatic regions, and their functions have covered heat-reflective coated glass in terms of energy efficiency. 

 

4、Comprehensive parameters of several types of glass 


The following insulating glass has the same structure, and the coated surface is located on the 2nd# surface of the insulating glass (the inner surface of the outdoor glass) Description: 6C means 6mm transparent glass, CTS140, CES11, CEB12 are the heat-reflective glass and Low-E glass models of SCG respectively. The heat transfer coefficient is the value under the standard condition of ASHRAE in the United States. 

 


The analysis shows that under the same transmittance, the shaded Low-E glass has a lower shading coefficient SC, which means that it restricts solar thermal radiation while not blocking the visible light transmission too much, and in layman's terms, it filters out the heat from the sun. The cost of obtaining a low shading coefficient SC for heat-reflective coated glass is that it significantly affects the natural lighting in the room.  


     
Low-E glass, also known as Low-E coated glass, is a special glass coated with a multilayer layer of metal or another compound that has a very low surface emissivity. The surface emissivity of ordinary glass is around 0.84, while that of Low-E glass is below 0.25. This low radiation film layer of less than one percent of the thickness of the hair has a high reflectivity of far-infrared heat radiation and can reflect back more than 80% of the far-infrared heat radiation, while the far-infrared reflectivity of ordinary transparent float glass, heat-absorbing glass is only about 12%, so Low-E glass has a good role in blocking the transmission of heat radiation. 

 

In winter, it reflects most of the heat radiation emitted by indoor heating and indoor objects back to the room like a heat reflecting mirror, ensuring that indoor heat is not dissipated to the outdoors, thus saving heating costs. In summer, it can prevent the heat radiation emitted from outdoor ground and buildings from entering the room, saving the cost of air conditioning and cooling. the visible light reflectivity of Low-E glass is generally below 11%, which is similar to ordinary white glass and lower than the visible light reflectivity of ordinary sunlight control coated glass, avoiding reflected light pollution. 

 

The production process of Low-E glass  


I. On-line high-temperature pyrolytic deposition method.  


Online high-temperature pyrolytic deposition method "Low-E" glass in the United States has a number of companies' products. Such as PPG Corporation

 


Surrogate 200, Ford's Sunglas H.R. "P". These products are made during the float glass cooling process. Liquid metal or metal powder is sprayed directly onto the hot glass surface, and as the glass cools, the metal film layer becomes part of the glass. This film is hard and durable. The "Low-E" glass produced by this method has many advantages: it can be heat bent, tempered, does not have to be used in a hollow state, and can be stored for long periods of time. Its disadvantage is that it has poor thermal properties. Unless the film is very thick, its "u" value is only half that of sputtered "Low-E" coated glass. If you want to improve its thermal performance by increasing the film thickness, then its transparency is very poor.  

 

2, The off-line vacuum sputtering method. 

The sputtering method can be used to produce "Low-E" glass manufacturers and products are North America's Intepe company's"LnplusNetetralR", PPG's Sungatel00, Ford's SunglasHRS, etc. . Unlike the high-temperature pyrolytic deposition method, the sputtering method is off-line.

 

There are horizontal and vertical glass transfer positions. The sputtering process is used to produce "Low-E" glass, which requires a pure silver film as a functional film. The pure silver film is between two layers of the metal oxide film. The metal oxide film protects the pure silver film and acts as an intermediate layer between the layers to increase the color purity and light transmission.


  
In the vertical production process, the glass is placed vertically on a shelf and fed into a large vacuum chamber. The pressure in the vacuum chamber is then reduced. Vertically mounted cathode targets sputter metal atoms, which are deposited onto the glass substrate to form a film layer. In order to form a uniform film layer, the cathode target is moved back and forth close to the glass surface. In order to obtain a multilayer film. Multiple cathodes must be used, each of which is moved back and forth across the glass surface to form a certain film thickness. 



The horizontal method is to a large extent similar to the vertical method. The main difference is in the placement of the glass, which is transferred by a horizontally arranged wheel, through the cathode, and the vacuum level changes after the glass pass through a series of pinning valves. When the glass reaches the main sputtering chamber, the coating pressure is reached, the metal cathode target is fixed and the glass moves. During the passage of the glass through the cathode, a film layer is formed.  



Low-E coated glass (also known as LOW-E glass) is a film system product consisting of multiple layers of metal or other compounds coated on the glass surface. The product has high transmittance for visible light, high reflectance for infrared (especially mid and far infrared), and good heat insulation performance. It can be used in any climate to control sunlight, save energy, control and regulate heat and improve the environment. According to different models, LOW-E glass is generally divided into high-transmittance LOW-E glass, sun-shading LOW-E glass, and double silver LOW-E glass. 

 

High-transmission LOW-E glass product characteristics:


1、Higher visible light transmittance: natural lighting and transparent effect.


2、Higher solar energy transmittance, more solar thermal radiation through the glass.


3. Very high reflection rate of middle and far-infrared rays: excellent heat insulation performance, lower V value (heat transfer coefficient).


Scope of application. 


1、Cold northern areas. Winter solar heat radiation through the glass into the room to increase the indoor heat, while the indoor heating, home appliances, human body, etc. emitted far infrared is blocked and reflected back into the room, effectively reducing the heating energy consumption;


2、It is suitable for buildings with transparent and transparent design and natural lighting, which can effectively avoid the harm of "light pollution". 


3、Made into an insulating glass with better energy-saving effect. 

 

Sun-shading type LOW-E glass product characteristics.


1、Suitable visible light transmittance, with a certain degree of shading to the outdoor glare. 


2、Lower solar transmittance, effectively preventing solar heat radiation from entering the room.


3、High reflection rate of middle and far-infrared rays, restricting the secondary heat radiation from outdoors to enter the room.

 

Scope of application.


1、Applicable to southern areas and northern areas. The product not only restricts part of the solar heat to enter the room in winter but also restricts more solar energy to enter the room in summer because the intensity of solar energy in winter is only about 1/3 of that in summer, thus the heat preservation performance is not affected. From the viewpoint of energy-saving effect, shading type is no less than high-permeability type. 

 


2, its rich decorative properties can play a certain outdoor achieved shading role, suitable for all types of buildings. 

 

3, made into insulating glass energy-saving effect is more obvious. 

 

Double silver LOW-E glass product characteristics: double silver LOW-E glass, named because of the double silver layer in its film layer, which belongs to the more complex structure of the LOW-E glass film system, is a senior LOW-E glass. It highlights the shading effect of glass on solar thermal radiation, combining the high light transmittance of glass with the low transmittance of solar thermal radiation, so it has lower solar transmittance with the same visible light transmittance compared with ordinary LOW-E glass. Scope of application: not limited by region, suitable for a wide range of areas with different climate characteristics. 

 

1, coated glass: coated glass is coated with one or more layers of metals, alloys, or metal compounds on the surface of the glass to change the performance of the glass. The different characteristics can be divided into heat-reflective glass and low-emissivity glass.



 Heat-reflective (sunlight control) glass, generally in the glass surface is coated with one or more layers of metals such as chromium, titanium, or stainless steel or its compounds composed of thin films, so that the product is rich in color, with appropriate transmittance of visible light, the high reflectivity of near-infrared light and very low transmission of ultraviolet light, therefore, also known as sunlight control glass. Compared with ordinary glass, the shading coefficient is reduced, i.e., the shading performance is improved, but the heat transfer coefficient is not changed much. 

 

2, low radiation (LOW-E) glass, is coated with multiple layers of silver, copper or tin and other metals or other compounds on the surface of the glass, the product has high transmittance of visible light, a high reflectivity of infrared light, with good thermal insulation properties, due to the poor strength of the film layer, is generally made of insulating glass used rather than used alone. 

 

3, coated glass and insulating glass composite: including heat-reflective coated insulating glass and low-radiation coated insulating glass. The former can simultaneously reduce the heat transfer coefficient and shading coefficient, the latter has a better light transmission 
   


Online Low-E (LOW-E) coated glass is a new type of energy-saving coated glass with high reflectivity to mid-and far-infrared radiation. It is made by continuous pyrolysis of coating raw materials at high temperature in a tin bath and annealing kiln using CVD and MOCVD processes and deposited on the moving glass surface to make low-emissivity coated glass. Since the film is formed continuously at high temperatures, there is no need for warming, cleaning, and drying, so the production scale is large, the production cost is low, and the film layer is firmly bonded to the glass. It can be used in a single piece and can be thermally processed, which is a must-have material for curtain walls and window bodies to realize energy saving in buildings. 

Bluestar online Low-E (LOW-E) coated glass is divided into two categories, one is the net color Low-E coated glass, not only to maintain the visible light transparent glass high transmission performance while having excellent low radiation function. The second is colored low-emissivity coated glass, which has both good light transmittance and shading and excellent low-emissivity function. 

 

Heat insulation, sun shading, and low radiation are all good manifestations of the concept of energy conservation. The multiple combinations of various products carrying the concept of energy conservation provide the possibility of insulating glass processing options, which are a good basis for achieving energy conservation standards in buildings.  

Product features.

  
 Efficient energy-saving and environmental protection: good heat insulation and thermal insulation properties, are the ideal energy-saving and environmental protection materials.  


 Excellent light-gathering property: high visible light transmission ratio, with good light-gathering effect.   


Stable chemical performance: it can be used in a single piece and can be stored for a long time, giving full play to the own advantages of deep processing enterprises.  

Stable thermal processing performance: can be arbitrarily toughened, heat bent, laminated and other types of deep processing.  

  
Stable mechanical properties: the film layer is firm, has good wear resistance and is not easy to scratch.   When hollow processing, there is no need to remove the edge film layer.   The in-line and continuous production process, large scale and
High production efficiency.    Diversified varieties and many colors can be produced.   

 

Coated glass is also called reflective glass. 

 

Coated glass is a glass surface coated with one or more layers of metal, alloy or
It is used to change the optical properties of the glass to meet specific requirements.  
Depending on the characteristics of the product, coated glass can be divided into the following categories: heat-reflective glass, Low-E glass (Low-E), an electrically conductive film glass.



Heat-reflective glass is generally coated with one or more layers of metals such as chromium, titanium, or stainless steel or their compounds on the glass surface.
Stainless steel and other metals or their compounds composed of thin film, so that the product is rich in color, for visible light have a proper transmittance, infrared has a high reflectivity, the high absorption rate of ultraviolet, therefore, also known as sun control glass, mainly used in buildings and glass curtain walls.



low-emissivity glass is coated on the glass surface by a multi-layer silver, copper, or tin and other metals or their compounds composed of thin-film system, the product has high transmittance of visible light, a high reflectivity of infrared light, with good thermal insulation properties, mainly used in buildings and cars, ships and other vehicles, due to the poor strength of the film layer, is generally made into hollow glass use. 

 

Conductive film glass is coated with conductive films such as indium tin oxide on the surface of the glass, which can be used for heating, defrosting, defogging and as liquid crystal displays, etc.

  

Coating glass production methods are many, mainly vacuum magnetron sputtering method, vacuum evaporation method, chemical vapor deposition method, and sol-gel
The main methods of production of coated glass are vacuum magnetron sputtering, vacuum evaporation, chemical vapor deposition, and the sol-gel method.

Magnetron sputtering coated glass using magnetron sputtering technology can be designed and manufactured multi-layer complex film system, can be coated with a variety of colors on a white glass substrate, the film layer of corrosion and wear resistance is better, is currently one of the most produced and used products. 

 

The variety and quality of vacuum evaporation coated glass compared with magnetron sputtering coated glass are a certain gap, has been gradually replaced by the vacuum sputtering method. 

 

The chemical vapor deposition method is in the float glass production line through the reaction gas in the burning glass surface decomposition, uniformly deposited on the glass surface to form a coated glass. The method is characterized by low investment in equipment, easy to regulate, low-cost products, good chemical stability, can be thermally processed, is one of the most promising production methods. Sol-gel method of production of coated glass process is simple and stable, the shortcomings of the product are too high light transmission ratio, decorative poor.  

 

The most used coated glass is heat-reflective glass and low-emissivity glass. Basically, two production methods are used: vacuum magnetron sputtering and chemical vapor deposition.