When selecting a solar panel brand, people usually take a close look at topics such as the efficiency and wattage of a solar PV panel. An often overlooked issue is the type of solar panel glass used.
Solar panel glass is one of the important barriers which protects solar photovoltaic cells against damaging external factors, such as water, vapor, dirt, and other harsh weather conditions
So why is glass used in solar panels?
What is solar glass
Solar glass this a kind of glass that used in solar panels, it can withstand extreme weather conditions. The solar panel glass also offers low reflection, high transmissivity, and high strength.
The difference between solar panel glass in thin film and crystalline solar panels
Thin film solar panels often have standard glass because they are cheap.
In crystalline solar panels, 3 to 4-mm thick solar glass is often used. The thicker the glass in the crystalline solar panels, the more stable are they. Solar panel glass on cheaper modules may be as thin as 2.5mm.
The solar panel glass (in the crystalline solar panels) is not standard glass it has a rough surface. This is necessary to make the EVA film bond well to the solar panel glass during the lamination process. Smooth glass can lead to delamination.
What properties are expected from solar panel glass?
The glass which is used in solar PV panels is of immense importance as it can make a big difference to the solar panel efficiency and therefore the yield of the solar PV system.
Solar panel glass should ensure a high solar radiance transmittance
The primary purpose of solar panel glass is to transmit as much sunlight as possible into the module.
A highly transmissive solar panel glass has a direct positive effect on the performance and yield of solar PV panels.
Antireflex (AR) coated solar panel glass
An anti-reflective (AR) coating can be added to solar panel glass by plating one layer of anti-reflection film before the glass is tempered.
The additional antireflex (AR) coating on the solar panel glass reduces the amount of reflected light and increases the percentage of absorbed sunlight from solar photovoltaic cells by 2.5%.
It also contributes to the high efficiency and mechanical stability of the solar PV panel.
Solar panel glass should guarantee strength and safety
Solar panels are made of tempered glass, which is also referred to as safety glass or toughened glass. It is created by thermal or chemical means.
There are specific characteristics that make tempered glass suitable for the manufacturing of solar PV panels.
Firstly, tempered glass is up to four times stronger than standard plate glass. Secondly, tempered glass is considered safe. When it breaks, it will shatter into small pieces reducing the probability of serious injury.
Both strength and safety are necessary for the installation of solar PV panels.
Solar panel glass, as the front sheet of a solar PV panel, needs to provide long-term protection against the natural elements. Glass was chosen because it is well-known for its durability.
The Weight of solar panel glass
Glass is heavy, for example, a standard 250W c-Si solar PV panel with a 3.2mm thick piece of glass weighs around 20kg. Many solar installers accept this heavyweight as it is currently the industry standard.
However, several companies are working on ultra-lightweight solar PV panels.
The dangers of cheap solar panel glass
To avoid this problem, look for solar PV panels that utilize tempered glass. This should be clearly stated in the solar panel data sheet.
If the chosen solar panel has the certificates of IEC (IEC61730, IEC61215) and UL1307, this means that the solar panel glass of this panel has withstood the quality and safety tests!