Solar glass can be used to reduce energy costs.
Solar glass is a type of window and building material designed to block radiant heat transfer, which is basically the amount of heat from the sun that passes through the glass and into whatever space is on the other side. This type of glass is most commonly used in windows in office buildings and homes, although it is also sometimes used in automobiles and in industry, often in panels in warehouses or machinery exposed to a lot of solar radiation. There are several different coatings that can be applied, each with its own specifications. Most are designed to reduce heat absorption and improve insulation, which can reduce energy costs.
In essence, solar glass is the combination of solar technology and standard window glass. Most of these windows don’t look any different than their more traditional counterparts; they are equally bright and generally let in the same amount of light. What they typically don’t allow, or at least don’t allow in, is radiation, which is energy emitted by the sun. This is achieved through an invisible coating that is applied to the glass before it is even installed. Most of the time, this coating is permanent and is designed to last the life of the glass.
why are they used
This type of glass is usually designed to reduce heat loss but allows sunlight to enter to warm it up, a concept also known as “solar gain”. There are a few reasons why this is important, but reduced energy costs are a big factor. Windows are an important source of natural light, but they can also be difficult to insulate. Outside elements, whether hot or cold, often penetrate window settings much more easily than walls or doors, and much of this has to do with the permeability of the glass itself.
Glass that has been coated to maximize solar energy can go a long way towards retaining energy, and these types of high-performance glass products are used in many industries. Recent advances in solar technology, at least as far as glass is concerned, include laminated products that boost solar energy. This concentrated solar energy reflectivity (CSP) provides efficiency and durability.
how are they made
Glass windows coated with a low-emission (low-E) coating block radiant heat transfer. This decreases the amount of heat that passes through the window. Low-E coatings are nearly invisible and are usually made of layers of metal or metal oxide on a glass surface.
Depending on energy needs, different types of low-E coatings allow high, moderate or low solar gains. In layered glazing, heat can be transferred between the panes of glass, usually passing from the heater to the cooler. Placing a low-emissivity coated panel in the space between the layers of glass helps to lock out heat. In the past, window technologists have filled this gap with dry air or nitrogen.
Today, argon and krypton gases are most commonly used between panels, which has improved the performance of windows. Both gases are non-toxic and non-reactive. Krypton is more expensive than argon, so some manufacturers combine the two gases to improve thermal performance at a more reasonable cost. Double-glazed windows with argon gas fill between the low-E coated glass panes are called pyrolytic, which means “hard cladding”.
High solar gain glass is best suited for windows in cold climates. In contrast, low solar gain or spectrally selective low emissivity glazing is more beneficial for buildings and homes in warm climates. These products reduce heat loss in cold climates, but also reduce heat gain in hot climates. Spectrally selective solar glass outperforms most colored and reflective glass. The allowable visible light level is generally high in proportion to the amount of heat reduction.
For climates that require heating and cooling during different seasons, all low emissivity coating levels can result in lower annual energy bills. Solar-optimized glass is practical for windows, doors and skylights. Commercially, it is used for the upper surfaces of thermal collectors and photovoltaic modules. Solar glass is almost always colorless, but in most cases it can be patterned for optimal solar energy transmission.