It is important to distinguish two types of photovoltaic panels: “standard” panels and Low luminance panels.
All panels in the FLASH range are made up of an anti-reflective glass on the front, composed of a thin porous layer of silicon dioxide deposited on the surface of the glass, making it possible to increase transmission of the glass to around 95% at normal incidence (compared to around 91-92% for untreated glass). This type of glass became popular in the early 2010s and is now a standard component in our industry. A reflectance test valid for all standard panels in the FLASH range determined that approximately 4% of light at normal incidence is reflected by the front glass over the 380-1100 nm range (evaluated value: 3.95% ). Furthermore, approximately 1% of the light is absorbed by the glass, the rest of the light is transmitted towards the cells.
Low luminance panels
Also called anti-glare. These panels are made of textured glass so that the light reflected on the surface of the panels is more diffuse, reducing the risk of glare compared to a standard panel. The regulated luminance for this type of module is less than 10,000 cd/m², i.e. below the threshold of 20,000 cd/m² which was imposed by the DGAC (General Directorate of Civil Aviation) for installers of solar panels in the vicinity of airports until 2022. A certificate of low luminance of the so-called “anti-glare” glasses which will be used on this type of panel can be downloaded here (only available in french).
|Reflect on a standard panel
|Reflect on an anti glare panel
For projects in airport areas
(This is about french regulation, for other countries please refer to local regulations and laws)
The luminance threshold no longer seems to be imposed by the DGAC.
Indeed, the TECHNICAL INFORMATION NOTE of 10/11/2022 (French language) issued by the DGAC and the ministry seems subject to interpretations, which does not favor the serene realization of projects in airport areas.
Before starting the costing of this type of panel, we therefore now ask:
- A reverberation study* validated by the DGAC confirming the need for a low luminance module,
- A project greater than 300kWp or a portfolio of potential projects for this volume because the minimum order is a container of 806 FLASH 375 Half-Cut White - Low Luminance modules,
- A written confirmation from the local DGAC certifying that the Low luminance glass certificate - 20,000 cd/m² from DualSun is accepted as the technical reference for the future module.
If these 3 elements are validated, we can offer you a specific production of FLASH 410Half-Cut White - Low Luminance (additional cost to be validated for each project).
For countries other than France, a specific study of the regulation must be done to be in accordance with the local laws.
According to what standard are luminance tests of solar panels carried out?
There is no specific standard for testing the luminance of solar panels.
The best-known standard on this subject, but which does not directly mention the determination of luminance, is ISO 9050-2003 "Determination of light transmission, direct solar transmission, total solar energy transmission, transmission of ultraviolet and factors derived from glazing ".
The low luminance glasses that DualSun offers have been tested in-house by our glass supplier. These tests show that the luminance of treated glass is limited to 15-20% of that of a panel with standard glass.
> To go further : What is a bifacial module? What performance gains does it allow?