Low emissivity coated glass is also called Low-E glass. Low-E glass is to coat low emissivity silver and metal oxide layers on glass surface. The coatings on glass will show different colors. Its major properties is to lower the U-value and selectively lower the SC which on the whole improves the glass energy efficiency. It features high infrared reflection. It can directly reflect far infrared. Because of its low surface emissivity(E), it absorbs and re-radiates very little energy. It has a wide range of shading coefficient(SC) which can meet different solar control requirements according to different climates. It can be divided into high transmission low-E glass and solar control low-E glass.

High transmission Low-E glass has shading coefficient Sc≥0.5 which does not reduce too much solar heat. It is very suitable to be used in the northern area where heating system is adopted. In winter, sun rays can transmit through this type of Low-E glass into the room and the energy is absorbed by interior objects. The objects in the room will re-rediate far infrared which cannot pass through the Low-E glass. Such solar heat is confined indoors together with the heat from the indoor heaters. Thus, heating costs can be reduced.

Solar Control Low-E glass has shading coefficient Sc＜0.5 which can reduce solar heat transmission. It is very suitable to be used in the southern area where air conditioner is used for cooling. In summer, it can block solar heat from entering the room as well as to block scattered far infrared from outdoors. Thus, the costs of air conditioning can be reduced.

According to the number of silver layers in the coating, it can be categorised into single-silver Low-E glass, double-silver Low-E glass and triple-silver low-E glass. In some occasions, requirements of high visible light transmittance and very low shading coefficient is needed. This drives the development of Double-silver Low-E glass. In general, double-silver Low-E glass has higher visible light transmittance than single-silver Low-E glass when both have the same SC. This feature is even more obvious in Triple-silver Low-E glass. Double-silver glass has a wide range of application. It has the following characteristics: lower shading coefficient than solar control Low-E glass, low emissivity allow good heat preservation, low reflectance, and better transmittance.

● Definition of Low-E insulating glass, comparison between monolithic clear glass and clear insulating glass in energy saving
Low-E insulating glass, a recognised energy saving building material, is advocated to use in green architecture by the country. It can meet or even out perform the requirements stated in the national standards for energy conservation of materials used in public buildings and residential buildings. The Low-E coating is made by using vacuum magnetron sputtering technology to deposit metallic silver and auxiliary layers on glass surface. It is then assembled with another piece of glass as an insulating glass unit enclosed with dry air. Compare Low-E insulating glass with clear insulating glass, it’s silver layer has high reflection to solar heat. This keeps away solar heat from outdoors while allows good natural lighting indoors in summer. In winter, it prevents indoor heat from getting out of room through the glass so as to conserved building energy. Low-E insulating glass can better preserve energy than monolithic glass upto a saving of 67-70%. It also saves around 40% more energy than clear insulating glass (see the table below).

● Solar-E Laminated Glass (Third Generation Low-E Laminated Glass)
Solar-E laminated glass refers to an energy-saving laminated glass made by laminating vacuum magnetron sputtering Low-E glass with special technology. Solar-E laminated glass has more varieties in types, colors, performance, and wider applications. The Low-E coating is also more stable in fabrication with good adhesion and resistant to acid and alkali when comparing with XIR type laminated glass.

● Equipment and Capacity
The Low-E glass production line in Xinyi Glass Engineering (Dongguan) Co., Ltd is from VAAT Germany. It adopts the state-of-art vacuum magnetron sputtering technology which is one of most advanced Low-E glass production line in terms of output, product types and technology in China. With the latest medium frequency rotating cathode technology, it improves the sputtering rate and the coating density to make the coating more rigid. The use of high purity and density imported targets together with online photometers ensure the consistence of coating color. Different types of high quality Low-E glass including high transmission Low-E glass, solar control Low-E glass, double-silver Low-E glass and temperable Low-E glass can be produced. It is equipped with Bentler washing machine from Germany using circular brush, roller brush with purified water(deionized water) in three washing sections  for cleaning which can thoroughly clean the glass effectively and ensure the coating quality. Inspection equipment such as Lambda950 photometer and Colorquset XE made in America as well as advanced optical performance detector made by Insitu and Exsitu in Germany (infrared detecting machine) are used to measure the parameters such as coating, color, as well as transmittance and reflectivity of solar energy and visible light, so as to ensure our products meeting customers’ requirements.
The coating products manufactured by our company is durable and meeting international standard in both physical and chemical aspects.

● Specification
◆ Glass thickness: 3mm～19mm
◆ Maximum size: 3300mm﹡6000mm

● Output
Annual output: 38,000,000m2

● Quality Standard
Conforming to GB/T18915.2-2002 national standard for coated glass and Xinyi’s company standard for “Low-E Glass”

● Performance Parameters of Xinyi LOW-E Glass and SOLAR-E Laminated Glass
Data-Single Low E.pdf
Data-Double Low E glass .pdf
Data-Triple Low E.pdf

◆ Terms
Visible light transmittance: Percentage of visible light transmitted through a glass type within the range of visible light spectrum (380 nanometers to 780 nanometers)
Visible light reflectance: Percentage of visible light reflected from the glass surface within the range of visible light spectrum (380 nanometers to 780 nanometers)
Solar energy transmittance: Percentage of ultraviolet light, visible light and near-infrared light transmitted through a glass type within the range of solar spectrum (300 nanometers to 2500 nanometers)
Solar reflectance: Percentage of ultraviolet light, visible light and near-infrared light reflected from the glass surface within the range of solar spectrum (300 nanometers to 2500 nanometers)

▲ U value: Rate of heat transfer from air to air due to glass thermal conductance and temperature difference between indoors and outdoors under ASHRAE standard conditions. Its imperial unit is: Btu/h/ft2/℉; its metric unit is: watt/m2/℃. The lower the U value, the lower is the rate of heat transfer through the glass. U value measures the amount of heat transfer through glass due to convection and conduction including re-radiation after glass absorbs heat. Therefore, the lower the glass emissivity, the lower will be the U value.
Amount of heat transfer by convection and conduction = U value × (TO– Ti)
TO and Ti are the outdoor and indoor temperatures respectively.
If the temperatures of two sides of glass are respectively TO and Ti, the amount of heat transfer through glass with an area of S within the period of t is W.

▲ Conditions of U value in winter: Outdoor air temperature: 0℉(-18℃); indoor air temperature: 70℉(21℃); outdoor air velocity: 15mph (24km/h); natural convection of indoor air; sun light intensity: 0BTU/h/ft2 (0W/m2) (nighttime)

▲ Conditions of U value in summer: Outdoor air temperature: 90℉(32℃); indoor air temperature: 75℉(24℃); outdoor air velocity: 7mph (12km/h); natural convection of indoor air; sun light intensity: (783W/m2) (daytime)

▲ Shading coefficient (Sc): the ratio between the solar radiation transmitting a glass type and the solar radiation transmitting 3mm transparent glass (the solar radiation transmitting 3mm transparent glass is 630W/m2)
Sc = Solar Radiation transmitting a Glass Type ÷ 630w/m2
Shading coefficient (Sc) measures the rate of heat transfer by direct solar radiation transmitted through glass.

▲ Relative Heat Gain: total instant heat gain when solar energy transmitted through the glass; including heat gain by solar radiation (shading coefficient) and heat gain by conduction (U value). The lower the relative heat gain, the better is the performance.
Relative Heat Gain = U value × (TO– Ti) + 630 × Sc [W/m2]