The glass we're talking about here is "flat glass", which is comprised of float, rolled, patterned, and drawn glass.
Float Glass
Float glass is the one that’s commonly used in solar panel production and offers the best quality at a low cost. Once the raw components are all in one batch, they are taken to a furnace and melted. This molten glass is poured into a bath filled with molten tin.
Inside this bath is a mixture of both hydrogen and nitrogen gas, preventing the tin from oxidizing. And due to the tin being denser than the molten glass, the glass covers the tin, making for a smooth and leveled surface.
Before the glass is incorporated into the solar panel, it’s inspected and coated with lucite, or methyl methacrylate. This prevents the glass from being scratched or damaged when being handled.
Patterned Glass
Patterned glass is used to cover the crystalline silicon module. It has a shallow pattern on the surface of the glass that diffuses the reflection on the module’s surface.
The deeper patterns on this type of glass further reduce the reflection, but they also attract water and grime which can damage the glass. Drawn glass also makes use of a roller by rolling the molten glass through it is a much older technique than our previous contenders.
Low-Iron Glass
Glass with a lower level of iron oxide makes for a solar panel that has a greater sunlight transmission. This means that solar cells protected using low-iron are more efficient than the ones shielded by soda-lime. The solar transmission found in soda-lime glass is around 85%, but in low-iron glass, it’s a whopping 91%, sometimes exceeding that amount.
As you can imagine, the production cost for low-iron glass is much higher than your standard soda-lime glass. However, the better transmission and overall quality of the glass itself justify its asking price from the more experienced solar panel users.
Sometimes manufacturers will also apply an anti-reflection coating after the bath using chemical vapor deposition. This uses thermally induced chemical reactions at the surface of the bath to coat the mixture.
The coating reduces the amount of light being reflected and increases the percentage of the sublight being absorbed from the photovoltaic cells. The glass-tin material is then placed in an oven that allows it to cool and prevent cracking.
As we know, glass plays an important role in keeping a solar panel strong and functional. Adding that extra layer of protection ensures that you are getting the most out of your solar panel and keeping it safe from any external threats. Whichever glass your solar panel uses, know that it’s an important feature to ensure that your solar panel lasts for years to come.
