The list of the most important problems of concern to potential owners of their own solar power plants always includes the question “can hail beat solar panels.” Buyers’ concerns are understandable, as photovoltaic cells are protected from external influences by glass or plastic films. And these materials, unlike metals, are psychologically associated in people with something not particularly durable. In view of the importance of this issue, we will analyze it in detail.
Solar panels and hail – how durable modules are
All high quality panels have a very high mechanical strength of the surface protective coating. Its ability to withstand static and dynamic loads is tested many times, and at different stages of manufacture.
Manufacturers from the TOP world rating TIER-1 practice additional multilevel testing according to the IEC 61215 standard. It is ordered from specialized companies and is confirmed by a certificate of conformity indicating the parameters of strength characteristics.
Even strong and large hail has practically no effect on solar panels of this level. The integrity of the surface coating is completely preserved, and the life of the glasses for protecting solar panels is at least 25 years.
Types of surface protection
There are two main types of glass protective coatings. Their main difference is the material used and the method of its manufacture.
1. Sheet glass.
Characterized by:
- low mechanical strength due to instability of the internal structure;
- maximum cheapness;
- rapid loss of performance;
- indefinite service life.
Hail, even the size of small peas, can render such solar panels inoperative due to irreversible damage to the glass structure, the appearance of cracks and a violation of water resistance.
It is allowed to use modules with such protection only in regions where there is practically no hail and strong dust storms.
Previously, their use was justified by the requirement to reduce the mass of panels to the limit, but with the advent of solar thin films, even this need disappeared.
2. Tempered glass.
Characterized by:
- high resistance to shock, chemical and thermal types of external influences;
- layered structure that increases dynamic resistance;
- service life of at least 25 years.
Tempered glass is more expensive, but you will not find reports that hail has broken such solar panels.
Technological process for determining strength
Each photovoltaic panel certification authority has its own procedure for assessing the strength properties of protective coatings. In general, they differ slightly, and the most prestigious company in this area is Thüringen e.V. (aka TÜV) from Munich, Germany.
The certificate of this company is considered a guarantee of the highest quality, and the testing process is carried out according to the list of standard tests IEC 61215. Technically, it includes the following stages:
- to determine if solar panels can withstand hail, the panels are rigidly fixed;
- then begins their “shelling” with ice balls with a diameter of 25 mm each;
- the speed of departure of “shells” from special barrels increases in stages until it reaches 23 meters per second (approximately 83 km / h);
- if, after 30 minutes of bombardment, the sample surface does not receive any visible damage, the highest degree of hail resistance is assigned to it;
- in the certification certificate TÜV International Certification, the test data are contained in clause 10.17.
To facilitate and facilitate the verification procedure, the international concern TÜV maintains branches in 62 countries of the world. In our country, the official representative of TÜV is TÜV International RUS Ltd.
Solar panels and hail – what experts say
Practitioners and test engineers say the following about certified panels:
- to seriously damage the tempered glass, the size of the hailstones must reach a chicken egg, the flight speed must be at least 100-120 km / h, and the direction of fall must be strictly vertical;
- despite the fact that natural disasters of this magnitude are extremely rare, the equipment is still recommended to be insured;
- The most durable surface protection today is possessed by a photovoltaic system from Tesla Elon Musk. According to the documentation, its composite structure is capable of withstanding any hail at all, regardless of size.