The recent trends across optical coatings in various glass industries have been studied for large range of climate dependent applications. Various coated glazing have displayed their various optical and thermal characteristics.

Across the world there is an increased trend to reduce energy consumption that requires variety of energy saving measures. The large amount of consumption of energy for cooling buildings that appear threat to environment. A major part of the architects job is to identify and the right glass to produce low-energy. Natural light is often allowed into the building through the use of glasses, by passing of solar energy in direct and indirect form.

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The recent trends across optical coatings in various glass industries have been studied for large range of climate dependent applications. Various coated glazing have displayed their various optical and thermal characteristics.

Across the world there is an increased trend to reduce energy consumption that requires variety of energy saving measures. The large amount of consumption of energy for cooling buildings that appear threat to environment. A major part of the architects job is to identify and the right glass to produce low-energy. Natural light is often allowed into the building through the use of glasses, by passing of solar energy in direct and indirect form.

With the help of this study we would be able to see how optical coating which is energy-efficient can help residential and automotive purposes.

As per studies, it has been proved that architectural standards in green or sustainable building design, glass selection is the main factor of having a green building. The past 4 decades have seen the development of use of thin film coating to improve the thermal performance of window glazing and to display a new and appealing visual of building design.

Presently the performance is monitored at Solar Heat Gain Coefficient (SHGC), the heat transfer coefficient (U-value) and the visible light transmission. The U-value measures the insulating value of a window; the lower the value, the better the insulation. SHGC 1s the ratio of the solar heat gain through the window system relative to the incident solar radiation and T, is weighted for human eye sensitivity.

The lower the SHGC, the lower the amount of solar heat is transmitted through the window thus reducing the overall cooling cost. The window U-value is of great importance in heating dominated windows. The lower the U-value, the better the insulation value and the solar heat gain is an additional benefit. Presently various, new codes and standards are in place or in process of development this might be due to the growing needs cooling-dominated climates along with dual climate options.

An energy efficient window is capable of giving lighting and thermal comfort at the least demand of paid energy. In warmer climates the energy efficiency is achieved by using multilayer thin film coating on windows, which are transparent and reflect IR solar radiation. Similarly for the cold climates like Europe, it is important to have optical coatings on glass that can transmit sunlight across large range and reflect across the in-house radiation that are warm bodies and used in occupied space.

OPTICAL COATINGS FOR ARCHITECTURAL FLAT GLASS

Across the Chemical Vapor Deposition (CVD), numerous coatings that are less than a micron thick, are used to reflect visible and infrared wavelengths, these can be further deposited in the next few available seconds as the glass ribbon flows beneath the coaters. In the end of the seventies various vacuum coating technologies were used for the deposition of optical thin films over large area of glass substrates have received a constant growth. The main applications of these today are in the various fields of coatings and solar control coatings. Electro chromic glazing’s are growing popular as low-emittance emerging technology and is a viable option for dynamic control of solar energy and visible light.

The 3 main types of energy-efficient products are solar selective MSVD low-E, pyrolytic low-E, and MSVD (Magnetron-Sputtered Vapor Deposition) low-E. The pyrolytic and MSVD low-E types have lesser U values and hence work well in the warmer climates. The products that are MSVD low- E are also used in the both heating and cooling weather regions due to their lesser value of SHGC. The various solar selective MSVD low-E products contain the lowest amount of SHGC and often work best in the cooler areas. At the same time, MSVD products are far less durable and more reactive than their pyrolytic counterparts.

Low-Emittance (Low-E) coatings are extremely thin and can be seen through microscope, and almost invisible, metal layers of metallic oxides that are deposited on a window of skylight glazing surface Coating. They are used to reduce the U-factor and suppress the flow of heat. Coating a glass surface with low-emittance material in the gap between the glass layers along with radiant heat transfer thus reducing the overall heat flow. Various types of Low E-coatings have been created to allow high, moderate and low solar gain. High quality low-E coatings deposited by magnetron sputtering that are made of ultra-thin silver film placed between two transparent anti-reflective layers, typically metal oxides like SnO,, ZnO, TiO,.

Presently all lesser emissivity glazing are based on a thin silver film. To ensure the high amount of clear view of glass in the range of the seeable spectrum and to avoid the silver from corrosion, more anti-reflective and layers of high refractive materials that protect are used. Optical transmittance and reflectance spectra of the stacked-layers of TiO, and SnO, F displayed better optical properties of largely clear-light transmission and midrange of infrared reflection. The U-value plays an important role on protecting heating energy in cold weather conditions. The lesser is the U-value, the lesser is the heat loss. The least emissivity of the coating leads the heat radiation of warm bodies inside to reflect back into the heating space.

ENVIRONMENTAL AND ENERGY ISSUES

On an average the world uses 320 billion kWh of energy from fossil fuels and has already generated CO, in 2002 of 2.6 billion tons/year, which is predicted to grow during 2030 to 4.2 billion tons/year. As per the US DOE Energy Efficiency and Renewable Energy (EERE) over 25% of the heating and cooling energy bills in a typical home are due to bad inefficient windows, door and skylights and namely to the type of glass used. Glass plays an important element in the home energy efficiency. The clear single glass is highly inefficient as it leads to loss of energy and sunlight much energy. Glass is one of most important solutions to provide energy savings in buildings that continuously developed new products that ensure heat insulation and solar control further increase and improve efficiency and thus contribute to the net reduction in CO, emissions. Better performance glasses are helping to energy

The way coatings are deposited across large areas decides the production viewpoint. Owing to its high mass productivity and flexibility along with high research and development across the various sectors. Some of the other popular methods are applied that are, CVD, spray pyrolysis and sol-gel depositions have been their benefits to provide some products that are further likely to used more across the technological progress.

As per the studies done on various trends of architectural and automotive applications low-E glass is the most promising product. Owing to the greater selectivity of visible transmittance to solar energy gain that can be received by the use of an oxide with more refractive index. Also they are a lower deposition rate as compared to traditional sputter method and the innovative high deposition rate sputter techniques that have been already developed and are being used.