Ultimate vacuum glazing guide-2022 version
This article contains the development of vacuum glazing,main manufacturers in China,why vacuum insulating glass has low market acceptance and why HaanGlas is different.
Table of Contents
Architectural glass development
Glass is one of the most common man-made materials.With the development of glass production and technology,glass has been used in our daily life,whether it’s window&doors,household,phones,etc.
The main application in architectural industry,the function of glass has extended from initial lighting to now thermal insulation,sound proof,decoration,protect personal privacy ,safety and even more functions.
With more and more buildings constructed ,more people live in cities,the energy used in indoor heating and cooling process is increasing year by year,which also caused higher requirement in building thermal insulation.
Normal glass emissivity is 0.84, thermal insulation is 5.84W/M2.K and 5.28W/M2.K in winter and summer.To further decrease the heat loss,more and more technology and new glass products were invented:
Insulated glass: Insulated glass,also named insulated double glazing,double glazed panels,or double glazed units,it’s a hermetically sealed multi-glass combination consisting two or more panes separated by a spacer filled with high efficient desiccant .To ensure the sealing effect,first sealing finished by polysulfide adhesive and second by structural sealant.The most important function of insulated glass is reducing thermal loss,achieve lower energy consumption and good transparency.
Insulated glass decreased glass U value by 50% successfully,which is 2.7-2.8W/M2.K.Every part of the insulated glass can be further extended:
- Low-E coatings: Single silver low-E/Double silver low-E/Triple silver low-E coatings.
- Spacer:Aluminium spacer can be replaced with steel spacer,superspacer, warm edge spacer,TPS.
- Space gas: The air between glass can be replaced with argon,Krypton etc which has lower thermal transmittance.
- Glass thickness:Triple glass units with 2 spacers makes glass thicker and more energy efficient.
With these technology,double glass units minimum U value reach 1.1W/M2.K,triple glass units can have 0.6W/M2.K U value,meanwhile glass is becoming really thick-usually 45mm or more,which caused matched windows frame is becoming thicker and more expensive.
The emerge of vacuum insulating glass
To further decrease the insulated glass units is quite difficult,and overall costs will be double or more times higher.Then is there any better methods to make it more energy efficient?
Transfer heat from a high-temperature object to a low-temperature object: heat conduction, heat convection, and thermal radiation.
No matter how low thermal conductivity the gas inside insulated glass and the spacers,they contribute huge to the final glass thermal transmission.Then how about change the space to be vacuum?
The emerge of vacuum glazing was inspired by vacuum flask.Vacuum double glazing is based on the vacuum Dewar flask. In 1892, Cambridge University professor James Dewar invented the Dewar flask, which is a double-layer glass container, the walls of the two layers of glass are coated with silver, and then the air between the two layers of glass is evacuated to form a vacuum. Due to vacuum can prevent convection and conduction heat dissipation, silver coating can prevent radiation heat dissipation, therefore, the temperature of the substance in the Dewar is not easy to occur variety. Based on this, he summarized the two basic principles of vacuum insulation:
- Eliminate most of the heat convection and transfer through high vacuum conduction;
- Reduce radiant heat transfer through highly reflective coatings.
This has become the basic principle of the high thermal insulation performance of vacuum glazing.and also the main difference with traditional insulated glass.
The world 1st piece 1000*1000mm vacuum insulating glass samples was invented in 1993,Australia.Then NSG purchased the patent,produced vacuum glass products since 1997.
Mr Tang Jianzheng established Beijing Synergy vacum glass technology Co.,Ltd in 2001,unlucky for technology reason in that past 20 years,the finished glass ratio,Max size,high breakage ratio and high price blocked the acknowledgment and development of vacuum double glazing.
World main vacuum insulating glass manufacturers
In past posts,we listed several world main vacuum glass manufacturers in 2021,include AGC- Fineo vacuum insulating glass,NSG group-Spacia,Panasonic, Landglass.
Since 2019,More and more China vacuum double glazing factories were built ,new technology were applied on vacuum glass production,these factories include:
- Beijing Synergy vacuum glass:It was the 1stglass factory specialized in vacuum glass production,but stopped production in 2018,all its production equipment and other property were auctioned and obtained by Xinxinhousheng glass,then new factory was built in Tianjin- Tianjin Synergy and keep production.
- Part of Beijing Synergy researchers established Zerothermos in Sichuan province and keep the original production method and technology,annual output about 100,000sqm.
- China building materials academy worked with Beijing MGM and established vacuum production line,same as Synergy,the vacuum glass production line use glass solders to seal glass edge.After test,the vacuum glass produced has below features:
Max size:1500*2500mm; Surface compressure> 90Mpa.
After sealing process,glass strength decreased by 15%,unit piece production <30minutes.
Annual output >50,000 sqm.
- Qingdao Rocky Glass: Rocky glass and Hengda Glass ,as well as Tianjin Gushang Glass,Shandong Werkman vacuum glass.These 4 companies had some relationship ,but till now only Werkman has the ability to produce and supply vacuum glass products with glass solders edge sealing technology.
- Haer’bin Xinma Glass.The company’s R&D team has achieved breakthrough results in vacuum glass edge sealing technology and vacuum glass supporting pillar technology, and developed fully tempered vacuum glass. It produces 300,000 square meters of fully tempered vacuum glass production line, popular fully tempered vacuum glass production line and entry-level vacuum glass production line, and provides cutting-edge and stable fully tempered vacuum glass production solutions for glass deep processing enterprises.
There’re many other vacuum glazing factories in China,for example Henan Longwang glass,Qingdao Hengda,Hubei Jinger glass,etc.
Of course the most successful glass:Landvac glass, and following HaanGlas
Learn more: VIG Processing technology classification
Why vacuum glazing has low market acceptance?
Since VIG mass production since 1997, 25 years past,but the vacuum double glazing market is still small,and some factories was forced to stop production because no orders,why the market acceptance of vacuum glass is in low levevl, Personally I think it’s caused by below points:
1.Non tempered vacuum glass.
Till now,most vacuum insulated glass produced are still annealed VIG sealed with glass solders.For example Fineo,Spacia etc,the non-tempered glass has low strength which limit the large scale application in buildings.
The unstable quality is caused by multi factors,all these factors lead to one result:Uneven pressure on glass and cause glass breakage.
Edge sealing technology: Many glass manufacturers announced that they can produce fully tempered glass,but the glass solder edge sealing technology has its inherit shortage: The sealing process will cause glass edge anneal again and surface compression decrease by 10-15%,which will cause uneven compression on glass surface,causing high glass breakage ratio.In 2020, a project adopted vacuum insulating glass had 20-30% glass broken because of uneven-quality.
Gutters:The gutters are embed inside glass,whether it’s round shape or stripe shape along the glass edge,processors have to make grooves on glass ,while this will affect the glass strength as well.
Evacuation holes: The exist of evacuation holes,not only affect the visual appearance,but also affect glass strength as well,the strength concentration at glass holes will have high breakage ratio.
Supporting pillars.Some manufacturers use Cylindrical shape supporting pillars,when placing the pillars on glass,there’ll be some misplacing, or cannot support glass because of glass flatness,or big distance between pillars,these will lead to the concentrated pressure in the supporting pillars.
3.Max size limitation.
Now most factories max size reach 1500*2500mm, while still cannot be widely used in glass facade which always contain glass panels over 3000mm,which make it cannot be used as facade glass .
Even though now vacuum glass price is decrease,but price is still several times that of normal double glass units.In addition to the high risks( glass breakage,glass failing etc) ,real estate developers and architect still keep cautious attitude when selecting the glass products for their projects.
Despite above shortages,there’re still many reasons limit the application of vacuum double glazing,for example,VIG cannot be made into curved glass,cannot drill holes or notches on glass.
All these factors affect vacuum insulating glass final quality,it can be classified into:vacuum degree,edge sealing technology, even glss strength,glass lifetime,glass tempered or not.Learn more about 6 factors affect VIG quality.
Luckily Landvac and HaanGlas vacuum glass has overcome some shortage and can manufacture and supply stable quality VIG products from China.
Learn more:Vacuum insulating glass price & costs
Features of vacuum glazing
vacuum glass structure-HaanGlas Glass-China manufacturerThe biggest feature of vacuum glass,is the 0.3mm vacuum space between glass panels,which makes it new generation energy efficient glass and will finally replace current double glass units and even triple glass units.
Low thermal conductivity.
As we mentioned in above,the best possible U value for double glass and triple glass units are 1.1W/M.K and 0.6W/M2.K.
As the exist of vacuum space,the only conductive materials that allow thermal transmit from the outer piece to inner piece,are the edge sealing materials and the micro support pillars,it eliminate the air or argon transmittance through the glass.
Typically vacuum glazing thermal transmittance is 0.4-0.7W/M2.K when combining with double silver low-E products.
Excellent acoustic performance.
The sound transmittance medium is air,glass. Vacuum stopped the sound transmit the glass,and only vibration through the glass and glass edges,which makes the vacuum glazing has much lower sound transmittance compared with normal glass.
The calculated sound reduction of VIG reach 39Dbs, and actual test shows its performance >35Dbs as well.
Thin and light.
The VIG is sealed units with only 0.3mm vacuum space,total thickness is 6.3mm,8.3mm and 10.3mm,which is even thinner than laminated glass,only 25-40% that of insulated glass panels,which is perfect for historical buildings renovations without changing the original windows frame.When building new projects,vacuum insulating glass can also help decrease the windows frame thickness.
Weight varies from 15kgs/sqm to 25kgs/sqm,helps decreasing the overall facade and windows weight.
No condensation in low temperature.
VIG remain condensation free when the temperature difference between inner and exterior glass panels reach 70 ℃.It guarantee the glass transparency even been used in refrigeration industry.
Fully tempered vacuum glazing are made with 2 pieces fully tempered glass.The tempered glass used comply with EN12150 standard,also resist impact under test EN6276,and ASTM Z97.This ensure the mass application in glass facade and avoid possible injury.
Vacuum insulating glass can also be further processed to be vacuum laminated glass,vacuum insulated glass to further increase its safety performance.
Learn more: Fully tempered vacuum insulating glass features
Super long life.
After weather accelerating test,VIG can reach over 25 years lifetime,offering 25 years extremely low thermal transmittance and continuous save costs for house owners.
Gutters will continuous absorb water vapor or moisture penetrate inside glass and keep high vacuum condition.The mature and stable edge sealing technology will ensure no breakage,no failure until glass spontaneous breakage.
No expansion and no contraction.
When the altitude height difference of insulated glass production and installation reach 800M,it’s necessary to install capillary tubes to balance the air pressure,or facade will have visual distortion and affect appearance.
VIG is different,the vacuum space won’t change and affect glass shape,so it can be applied in any altitude and any height.
No performance change based on different angles.
The insulated glass performance is affected by installation angles.When installed vertically,it has the best performance, when the installation angle decrease,the U value in winter will increase and finally reach 2.47W/m2.K,which is 50% higher than vertically installed.
VIG get rid of this problems and always plays 100% whether it’s vertically installed or horizontal installed.
9.Excellent structural performance.
The tempered glass will avoid serious injury after installation,but VIG can also has excellent structural performance,especially up to 9000Pa wind load resistance,and 0.85 equivalent performance.
Learn more:Vacuum Glass structural performance
What makes HaanGlas vacuum glazing different?
Even though HaanGlas started VIG very late,but we now get the newest and latest technology and now one of the world best vacuum glass manufacturers.Our difference are:
1.Minimum thickness 6.3mm fully tempered vacuum insulating glass.
Minimum 3+0.3V+3mm fully tempered vacuum glazing for renovation projects & refrigeration industry.
2.Low temperature metal edge sealing process.
Edge sealing finished with low temperature metal to avoid glass anneal and stable quality.
3.No evacuation hole design.
No evacuation holes to keep absolute flat glass surface, <0.001 glass overall flatness .
4.Max 1700*3200mm available size.
New generation vacuum production lines produce max 1700*3200mm vacuum glass.But for different thickness,our recommended sizes are:
3+0.3V+3 vacuum glass:1000*1500mm
3+0.3V+3 vacuum glass:1700*2500mm
5+0.3V+5 vacuum glass:1700*3200mm
5.Super long warranty time.
HaanGlas offer up to 15 years warranty time for all the VIG supplied by HaanGlas.
Currently the world main vacuum glass price are USD200/SQM, thanks to our over 90% finished glass ratio and higher production efficiency,HaanGlas vacuum glazing price is much lower and affordable for more customers.Contact us with your detailed sizes and quantity required to get our accurate vacuum glass price.
7.Multi low-E coatings.
Different from other glass manufacturers,HaanGlas offer various low-E coating options to suite different climate,from single silver to double silver,high light transmittance to low transmittance,and even low-E coatings on body tinted glass,everything is possible.
Our Core coating options: Jinjing S1.16- 3mm/4mm , D80 double silver low-E -5mm or thicker.
8.Multi glass combination-laminated vacuum glass,insulated vacuum glass.
HaanGlas VIG can be further processed to be laminated vacuum glass – for example 5 LE+0.3V+5+ 1.52PVB+5 ,to help customers offer better safety performance and acoustic performance.
Insulated vacuum glass is also available to fit thick window frames,even though the extra piece won’t contribute much extra property ,when special performance is required,HaanGlas is able to offer solutions.
Application of vacuum insulating glass
1.Applying vacuum glass in high rise glass facade
VIG has been used in glass facade since early 2000s,especially the earliest VIG manufacturers such as Synergy,but for some reasons,such as non-tempered VIG has low safety performance,and high U value caused by low vacuum degree,now the VIG technology has developed and been much more suitable for large scale application in facade.
HaanGlas collect some info,regarding vacuum glazing equivalent thickness,wind resistance to help architects better designing the facade,but also summary the benefit of VIG application in facade.
2.Appication in historical windows restoration.
Traditional architectural glass products has high SHGC and poor thermal insulation effect which lead to high energy loss and uncomfortable living environment.During windows restoration, Increasing the glass thickness will not only affects its transparency and beauty, but also increases material consumption and construction cost caused by heavier loading . Especially when windows frame cannot be replaced in windows restoration, this contradiction is more prominent.
By applying VIG house owners can replace glass without changing original frame,getting more energy saving and a quiet living environment.
3.Application in refrigerators
Refrigeration display cabinets, as a necessary refrigeration tool in supermarkets,As the energy consumption of refrigerators account 70% of supermarket total energy cost,so it’s necessary to find solutions to decrease refrigerator energy consumption.
VIG can help refrigerators free from condensation,save energy ,prolong refrigerator lifetime and decrease its costs.
3.Application in conservatory
Glass conservatory,or glass sun rooms are liked by worldwide,it allow Max lights to enter the room in winter and bring comfortable,while in summer,it will make the sunroom high temperature and hard to stay inside,by using vacuum glazing in conservetory,it will help controling the conservatory temperature in summer and save heating energy in winter.
Future development trend of VIG
Even though there’re still many factors that block the development of vacuum glass,but Haanglas is able to solve and offer high quality VIG products.Other VIG manufacturers are also keep develop new customer friendly and environmental friendly products.This will cover increasing glass strength,make it larger,decrease the costs,and larger application in facade with lower U value that equivalent to wall.
Now More and more countries and areas has acted for Zero emission promise, European council agrees on stricter rules of building energy performance,and the inflatation reduction Act in USA also support investment in energy efficient and low carbon buildings, investors will get tax credit or subsidy to decrease the renovation costs, thin and light vacuum double glazing will be applied in more and more projects.
HaanGlas is your most reliable vacuum double glazing manufacturer in China, our SGCC/IGCC certified VIG will certainly helps in creating low carbon world,kindly contact us for more info.