Beat the heat with glass

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Summers in India can vary from being pleasantly sunny too unbearably hot. With the advancement in the technology, now people can opt for solar control glass, to meet their respective thermal control needs.

Solar glass is the combination of solar and glass technologies. These windows coated with a low-emittance (low-E) coating block radiant heat transfer. This lowers the amount of heat that passes through a window. Depending on energy needs, different types of low-E coatings allow for high, moderate, or low solar gains. Solar systems are often used to lower energy costs. The tendency of its solar control, depends a lot upon the manufacture of glass.

It is thus evident that Glass plays a crucial role in the energy conservation in a building performance. It becomes all the more accentuated in a tropical country like India, where the right choice of glazing will help in improving the energy performance of the building by a very long way. The usage of it in the country has been increasing exponentially overs the years and this has resulted in the added responsibility of it as a building material to provide the optimal functionality with respect to its intended purpose. Apart from the passive design considerations that influence the heat gain in a building and thus the energy consumption, It plays a role in terms of heat because of its inherent property of letting in light & heat. Now letting in the visible light will help in decreasing the artificial lighting as it provides for natural lighting to the floor spaces in the building. However It also lets in the near range infrared wave which is otherwise called as heat. A normal Clear float material will let in as much as 84% of the solar heat incident on it. This will have a severe strain on the cooling loads in the building. The intent will be therefore be to decrease the heat ingress inside the building.

Low-E coatings are nearly invisible, and made up of layers of metal or metallic oxide on a glass surface. The coating is transparent to visible light. In layered glazing, heat can be transferred between panes of this material, from warmer to cooler. Putting a low-E coated pane in the space between layers of the system helps block that heat. Window technologists in the past filled this gap with air or dry nitrogen.

Today, argon and krypton gas are used between panels, which has improved window performance. Both gases are non toxic and nonreactive. Krypton is more expensive than argon, so some manufacturers combine the two gases to improve thermal performance at a reasonable cost. Double-glazed windows with an argon gas fill between panels of low-E-coated sheet are called pyrolitic, or hard coated. This application is designed to reduce heat loss but allow sunlight in for warmth, or solar gain.

Solar sheet with high solar gain is best suited to windows in cold climates. Low solar gain, or spectrally selective, low-E glazings are more beneficial for buildings and homes in warm climates. These products reduce heat loss in cold weather, yet also reduce heat gain in hot weather. Spectrally selective solar material, out-performs most tinted and reflective glazings. The level of visible light lets in is high in proportion to the amount of heat reduction.
For climates that require both heating and cooling during different seasons, like India, all levels of low-E coating can result in lower annual energy bills. Solar glass finds application in windows, doors, and skylights.

Commercially, it is used for the top surfaces of thermal collectors and photovoltaic modules. The appearance of solar material is colorless, but can be patterned for optimal solar energy transmission.

High-performance glass products are used across many industries. Recent advances in solar material include laminated products that boost solar power. This concentrating solar power (CSP) reflectivity provides efficiency and durability.

Apart from solar control features, there are many varieties of glass to choose from, Patterned, Frosted, Lacquered and other variants. These options are attractive to look at and are also eco-friendly.