What’s the component of solar radiation?
The solar radiation include 3 parts: UV radiation (Wavelength range 0.01～0.38 microns),visible light (Wavelength range 0.38～0.75 microns),near infrared radiation(Wavelength range 0.75～3 microns).
What’s the difference between near infrared radiation and far infrared radiation?
Near-infrared radiation comes directly from the sun, and its heat is not obvious, but it can be converted into heat after being absorbed by an object.Near infrared radiation cannot transmit the glass directly,it can be only been reflected or absorbed by the glass,after glass absorbing the near infrared radiation,glass temperature will increase and become a radiation source itself.
Far infrared is a result of solar energy conversion or artificial production,such as the stove,house appliance, human body,and the furniture that lighted by the sun.In summer,the exterior road,buildings are the main source of far infrared after lighted by the sun.
What kind of thermal that are transferred through glass?
The energy that transferred through glass include direct solar radiation ,typical parameter to measure it is glass SC (Shading coefficient) and SHGC (Solar heat gain) .
The 2nd part is convection conduction of heat transfer.It’s related to the infrared radiation. U value is the parameter to measure ,and measurement are W/m²K.
Glass Heat transfer
Transfer heat from a high-temperature object to a low-temperature object: heat conduction, heat convection, and thermal radiation.
What’s glass SC ?
Glass SC is to measure the UV & visible light solar radiation transmitted the glass.
Glass SC is short for glass shading coefficient,which means Under the same conditions, the ratio of the solar radiant energy through the glass to the solar radiant energy through the 3mm transparent glass. The solar radiation energy through 3mm transparent glass is 630w/m2.
The higher SC value,the more solar radiation penetrated the glass to decrease heating costs in summer,it’s widely used in long winter areas.
The lower SC value,the better blocking effect of direct solar radiation and reduce the solar radiation energy entering the room,suitable for hot areas.
What’s glass U value?
The heat energy transmitted through the glass due to convection conduction, includes the transmission of heat energy after the glass absorbs the heat energy and then radiates outward&inward. Therefore,lower emmissivity,the lower U value.
What’s low e glass?
Low e glass is short for Low emissivity glass,is to have a multi layer coating composing metalic &chemical on glass surface to decrease the glass emissivity ratio from 0.84 to below 0.15,or even only 0.03.The typical emissivity of low e glass include single silver low-E,double silver low-E and triple silver low-E,which contains 1 layer, 2layer,and 3 layers silver coatings.Hard coated low e glass as relatively higher emissivity compared with the soft coated low e.
Hard coated low e VS Soft coated low e
Difference between Single silver low-E,double silver low e and triple silver low e
coating layer-single-double-triple silver lowe coating
coating layer-single-double-triple silver lowe coating
What’s the function of the low-E coating?
The feature of low e coating is thermal insulation.
The low emissivity coating can reflect the far infrared radiation directly,especially the silver layer inside the soft coated low-E coating can reflect 98% far infrared radiation like mirrors.
The coating has little capability absorbing the heat,which will control the glass surface temperature very well, the heat re-radiated out from the glass is little accordingly.
Despite controlling the infrared,the coating as a variety options with different visible light transmittance and SC value(0.2-0.7) to control the ratio of direct solar energy transmitted through the glass,which can be selected by users both in hot and cold areas.
insulated glass-heat transfer-morn bm
insulated glass-heat transfer-morn bm
What’s the difference between solar reflective glass and low e glass?
Solar reflective glass reduces the shading coefficient of the glass and restricts the direct solar radiation from entering the room through the glass, thereby achieving the purpose of reducing air-conditioning costs and saving energy.
Low-E glass reduces the U value of the glass to restrict the far-infrared radiation from penetrating the glass,in addition, the shading coefficient has a large adjustment range, which can effectively control the direct solar radiation energy entering the room.
What’s the mature coating types of low e glass?
There’re 2 kinds of low e glass,soft coated low e coating and hard coated low e coating.
Hard coated low e glass is manufactured on a float glass production line. This type of glass has a single variety, poor heat reflection performance. Its only advantage is that it can be used as monolithic glass or been laminated.
Soft coated low e glass is manufactured by the vacuum magnetron sputtering process .It has a variety of colors, excellent heat reflection performance, and obvious energy-saving characteristics. The disadvantage is that it must be made into insulated glass,or the coating will be oxidized once exposed in the air.
Does low e glass wok at night?
Yes,low e glass work anytime.No matter what kind of far infrared,whether it’s caused by the solar,or artificial far infrared,it can always reflect the infrared heat.
How does low e coating works in summer and winter?
In winter, the indoor temperature is higher than outdoors, and the far-infrared heat radiation mainly comes from indoors. Low-E glass can reflect it back indoors to keep indoor heat from escaping.
In summer, the outdoor temperature is higher than indoors, Low-E glass can reflect the exterior heat out to prevent heat from entering the room. For outdoor solar radiation, Low-E glass with low shading coefficient can be selected to restrict its entry into the room, thereby reducing cooling costs.
Low-E coating on surface #2 or surface #3?
Insulating glass has 4 surfaces, the number from outdoor to indoor is 1#, 2#, 3#, 4# surface.
In areas where the heating demand exceeds the cooling demand , the Low-E film layer should be on surface #3. Conversely, in areas where cooling demand exceeds heating demand (southern areas), the Low-E film should be on the 2nd surface.
Low e coating position-Surface #2 VS Surface #3
What’s the function of argon filled in insulated glass?
Argon is an inert gas, and its heat transfer performance is worse than air. Therefore, argon filled insulated glass will have better thermal insulation,lower U value, argon also protect the Low-E film.
How much Uv the low-e coating can block?
Ultraviolet is short-wave radiation, invisible to the naked eye, it accounts for about 2% of the total solar radiation. Ultraviolet rays can kill bacteria, but long-term exposure can burn human skin and eyes, and also cause furniture and clothing to fade.
Low-E glass can reduce ultraviolet rays by 25%. compared with clear glass, It cannot completely avoid furniture fading, but it can slow down the fading.
Do shades, trees and awnings affect the performance of Low-E glass?
These objects can restrict the heat and light entering the room through the glass window, that is, block part of the solar energy from passing through, but it does not affect the performance of Low-E glass.
Is the windows&glass installation angle affect the glass U value?
Yes,the glass U value and shading coefficient are not affected by the installation angle,while in winter,the glass U value increase significantly with the angle from 90degress to 0 degrees.So for glass roofs,skylights,please select a low e coating with better U value.
How the glass U value been affected by the installation angle?
What’s the effect combing the low e coating with body tinted glass?
There’re 3 kinds of combinations:
Coating directly on body tinted glass, clear low e glass + body tinted insulated glass, laminate body tinted glass with clear low e coated glass.
Tinted glass can further reduce the shading coefficient,thereby restricting more direct solar radiation from entering the room. Therefore, the combined effect of these three methods is very good, and it is more suitable for use in tropical regions. Combining with colored glass can also greatly increase its decorative effect.
But do pay attention that coating on tinted glass price is higher ,also contains many advantages and disadvantages.
glass curtain wall with tinted glass insulated glass-morn-china
glass curtain wall with tinted glass insulated glass-morn-china
What’s the lifetime of low e coating?
Hard coated low e glass lifetime is same as the glass lifetime.
Soft coated low-E glass,after unpack the glass package,it’s suggested to make into insulated glass asap,or the coating will be damaged or oxidized within 30 days or even shorter time.
Once been made into insulated glass,the coating lifetime is same as the glass sealing time.
Where can we buy high performance low e coated glass?
Hard coated low-E manufacturers in China include AGC, Jinjing, SYP,Kibing.
Hard coated low e options in China
As Soft coated low-E must be made into insulated glass,it’s suggested to purchase finished insulated glass with high performance low e coating directly,Morn glass is your turnkey coated glass supplier,our products include single,double and triple silver low e insulated glass,click below link to check our coated glass performance data:
W1.1 and W1.16 low E coating for greenhouse /conservatory
Morn-Coated glass performance data
Morn-Triple silver low-E glass performance data
What’s low e coated glass price?
The glass price varies based on different project requirement,generally the glass combination,glass size,materials used in the insulated glass ,and many other factors-glass packing,broken&replacement,shipping costs affect the final insulated glass price.
Need more help? Contact us through [email protected], our glass expert are ready to serve you.