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The importance of Solar PV Mounting System is self-evident, which it is relative with the safety, structural stability, reliability and anti-corrosive performance of the brackets. We analyze and share the issues that should be focused on the design or selection step of solar PV system in regions with different climates. To withstand natural disasters, we need to consider the factors which may influence the structure, this article will answer how to design and install a steady solar bracket in Typhoon prone/Rainy/Snowy/Salty landscape/Permafrost Area.
Typhoon Prone Area
With the advent of lightweight materials in recent years, it is also important to consider the risk of these building materials being blown away by the wind when designing to prevent roofs from being torn apart by air currents. Currently, many people install the homeuse solar systems on pitched roofs and flat roofs mainly. Flat roofs also including several types and there are also considerations for the installation site of the PV system, which need to take into account the installation location, installation direction, installation angle, load requirements, and the arrangement. So it is important to design and install a steady solar bracket.
How to deal with PV system before the typhoon?
i. Check the screws and welding ports of brackets;
ii. We should take waterproof measures for the electric boxes and inverters. For small slope of the roof, we should set them up in advance additional drainage system to prevent component soaking damage.
iii. The system as a whole should be well reinforced. Pay attetion with the environment near the solar PV system. Make sure there is no thing to scrape down trees and other objects.
How do we check the system after the typhoon?
First, check the power box, make sure there is no problem with the protector. Then confirm whether the solar panels are damaged. If found damaged, we must give the whole power station to do a physical examination. It is in order to prevent hidden cracks in the components which affect the whole system working safely. After these, clean up the debris on the panels to prevent shading from affecting the power generation of the system.
What are the key points in terms of typhoon prevention during installation and design?
i. Strength of PV mounts—The wind resistance of system is overwhelmingly determined by the PV mounts. Therefore, the system must strengthen the foundation as well as the strength of the bracket. It is also reasonably calculate the wind pressure and snow pressure. At the same time to ensure that the component frame strength, targeted design, strict control of product quality.
ii. The material of the bracket—In coastal areas, typhoons are relatively frequent and windy. The galvanized PV bracket is undoubtedly the best choice. The pressure resistance of aluminum alloy bracket is not as good as galvanized.
iii. Fasteners—The installation and design of the system is very important. We should not save on the screws and fasteners materials, the lack of fixed screws is often the culprit of serious losses when disaster strikes.
iv. PV bracket foundation—The system will be mostly used in the way of cement piers which is convenient. But when the typhoon attack will often lead to the displacement of cement piers and security risks. Therefore, for the coastal areas, we recommend to connect the solar PV system column to the floor. The windproof design should be more than 15 levels, and the length of the pressure block should be up to 8 centimeters.
v. Installation inclination—For coastal areas to be solid windproof, in considering the best installation angle should also consider the firmness of the bracket in the face of strong winds. In windy areas, the installation angle should be controlled within 10 degrees. If the installation angle is too large, it will also increase the risk of damage caused by high winds.
How to get a better solar mounting brackets in rainy area? Pay attention to these 3 points when heavy rain is coming:
Ground PV Sysyem
Ground-based photovoltaic racking installation should take into account the terrain conditions, geological hazards, water depth, flood levels, drainage conditions. Many fishery and light complementary project due to pond water level rise to the power station flooding, is the initial design of solar PV bracket height consideration is not comprehensive, coupled with poor drainage capacity and other reasons caused by the tragedy. Therefore, when selecting a site, not only to consider the cost, but should also to consider the subsequent operation of the safety issues.
Roof PV System
For the roof PV systems, the chance of being flooded is very small cause the construction. So in order to avoid damage to the PV system due to rainy weather, the main consideration is the roof loading capabilities, wind pressure load, snow pressure load, earthquake load. After the roof meets the load requirements. At the same time, the solar photovoltaic racking installation can not be arbitrary. We should orient the solar system installation process to the south. As the name implies is the power station facing south, so that you can fully accept the sun’s light. Installation angle is theoretically equal to or close to the local dimension, arrangement and spacing, which we need to combine them with local sunshine and roof structure size.
For the mainstream inverter manufacturers are basically IP65 protection level with waterproof performance. But the impact of prolonged rainy weather on the equipment is still very large. But WANHOS can do 10 years without rust, 20 years of steel does not reduce. Also 25 years still have a certain structural stability. This is a special requirement for the material of the stent, which make sure to design and install a steady solar bracket.
How to design and install a steady solar bracket in snowy area?
One way is to mount solar panels at a large angle. This reduces the rate of snow accumulation and eliminates the need to clear it from time to time. If you’re debating whether to go with 30 degrees or 40 degrees is, obviously 40 degrees is a much better option. If your panels are flat on the ground, think of all the snow or pollutants that will surely stay on the PV mounts for a long time and won’t slide down on their own.
Another way is to mount them with a small distance off the ground. The snow won’t build up at the bottom as it slides off to the point where it slowly builds up to cover the entire module.
If there is heavy snow piled up on the component after snow, we need to clean them timely. You can use soft objects to push the snow down, pay attention not to scratch the glass. Components have a certain load-bearing, but can not step on top of the components to clean. It will cause hidden cracks or damage to the components, affecting the life of the components. We generally recommend not to wait until the snow is too thick to clean, so as not to freeze the components.
The reflective effect of the snow will be a small boost to PV power generation in many cases, . If the snow does not cover the module, the snow on the ground will act as a mirror to emit sunlight back. So the power generation will increase. However, if the snow completely covers the modules, and only a small portion of the sunlight passes through the snow and hits the PV modules, then it will affect the solar PV system. So it needs more sttention to design and install a steady solar bracket in snowy area.
Ground mounting PV systems on salty landscapes require better anti-corrosion treatment countermeasures for foundation. So it needs more attention to design and install a steady solar bracket.
I. The photovoltaic bracket system mainly covers the support structure from the foundation connectors to the lower part of the component steel bracket between each other.
In the photovoltaic bracket material, installation standards and anti-corrosion treatment countermeasures for the selection process, the manufacturer should fully integrate with the national provisions of the relevant building standards.
i. Photovoltaic module bracket usually consists of C-steel. The manufacturer should carry out on its outer layer of hot dip galvanised rust treatment to meet the relevant national standards, that is, the average thickness of the galvanised layer control in 55μm and above, anti-corrosion cycle control in 25 years and above. In addition, the manufacturers should send the product to the national authority for testing. Take hot dip galvanising anti-deformation means, used to avoid the construction of hot dip galvanising triggered by significant deformation in order to ensure that the fasteners are not damaged by corrosion. All fasteners should be accepted stainless steel or zinc process. And the average thickness of the zinc control in 30um and above.
ii. For the steel ground anchor, bracket base connection, should choose the screw penetration type connection, of which the bolt from the foundation manufacturers supporting the provision. Ensure the adjustable of the bracket system in the direction of the vertical height of the construction deviation, based on the design elevation will be adjusted to control the range of ± 400mm, at the same time can be carried out in the range of stepless adjustment.
iii. In order to ensure that the corrosion resistance meets the 25-year life cycle of the project, the manufacturers should pre-produced all the structures in the factory and then assemble on the site of the bracket system. We usually take bolt connection between the components, do not weld on-site if the selection of round pipe components. Also control the pipe wall thickness at 2.5mm and above.
II. Photovoltaic racking system foundation corresponding to the use of steel structure material yield point tensile strength, elongation and a series of chemical composition and mechanical properties should meet the national carbon structural steel regulations.
i. It is very easy to suffer corrosion damange if we install the C-steel material screw pile foundation in the salty soil directly. In view of this, on the one hand, according to the national standard of C-steel foundation to carry out a good hot-dip galvanised rust treatment. On the one hand, the factory should also add anti-corrosion coatings to the C-steel material surface, by the installation of the foundation and the salty soil isolation, in order to ensure that the surface of the carbon steel material does not lead to the phenomenon of corrosion of the salty build-up.
ii. Cement is very easy to react with soluble salts, resulting in corrosion damage to the cement concrete installation base, in view of this, the factory should add anti-corrosion coatings to the cement base, so as to play a certain role in corrosion prevention.
iii. In order to avoid the installation foundation and soluble salt trigger reaction, and subject to corrosion damage, but also in the installation foundation to carry out cathodic protection means, through the corrosion object transfer, so as to achieve the purpose of protecting the foundation of photovoltaic bracket.
Above these, that’s how we design and install a steady solar bracket in salty landscape.
The difficulty in designing and constructing a steady solar bracket in permafrost area is what people tend to focus on. Permafrost regions generally have the following climatic and geological characteristics:
i. The temperature is low in winter, and the lowest temperature is generally below -20 °C;
ii. The soil quality is strong frost heave or extra strong frost heave soil, such as clay, powdery clay, and so on;
iii. Groundwater is abundant and the water level is high. Under the condition of rich groundwater and high water level, it is more difficult to construct the concrete free-standing foundation, concrete pile foundation and microcellular piling foundation which need to pour concrete. It is difficult to guarantee the quality of concrete pouring and maintenance. The extremely low temperature in winter in the permafrost region will affect them. The concrete bar foundation is more suitable for the area with level site and low water table (e.g. desert). In the permafrost area, this kind of foundation is prone to uneven lifting and tilting. The cost of spiral steel pipe pile foundation is higher. And it is not suitable for strong corrosive environment and fluid silt soil.
In summary, in order to prevent freezing, it is more suitable to construct a PHC foundation by reducing the pile length. It is more convenience and cost-effective in construction for solar PV mounting systems in the permafrost areas. This is the key to design and install a steady solar bracket
Under the action of freezing expansion force, the PHC foundation is mainly subjected to permanent loads in the pile length direction (the weight of the upper support of the PHC, the weight of the components, and the dead weight of the PHC, etc.). The tangential freezing expansion force of the frozen soil on the PHC. And the anchoring force of the soil below the frozen layer on the PHC. From the force analysis, it is not economical to completely rely on PHC anchorage to avoid uneven freezing and uplift when the maximum freezing depth is deeper in the region of strong or very strong freezing and uplift soils.
So here are some measures to prevent uneven frost lifting of PHC foundations:
i. Reducing the tangential freezing expansion force on the pile. It is the key to prevent the PHC foundation from lifting due to freezing. We can take measures to avoid direct contact between the PHC foundation and the frozen soil within the designed freezing depth. So as to reduce the tangential freezing expansion force of the frozen soil on the pile. In this project, we found that backfilling the pile perimeter with weakly frost-expanded medium-coarse sand as the isolation layer can reduce the tangential frost expansion force of the pile perimeter soil on the pile.
ii. Decrease the number of PHC foundations for each group of brackets, so as to reduce the probability of uneven freezing and uplift of PHC foundations. In the case of 20 modules per string, it is more economical to use 4 PHCs as foundation. The probability of uneven frost heave is also lower. It is also possible to use 2 independent bracket and foundation support strings, i.e., every 10 modules are supported by 2 PHC foundations. It can further reduce the probability of uneven frost heave of each PHC foundation. However, this program will increase a certain amount of bracket work. The incremental size needs to be reviewed and determined on a case-by-case basis.
iii. Adopt height-adjustable solar panel bracket, i.e. the bracket is designed to be fixed with the pile hoop. In the event of frost expansion of individual piles, the height of the clamped bracket can be adjusted to level the bracket and components. It avoids deformation damage to the bracket and components.
Above all, design and install a steady solar brackets means a lot to us. It is not only for houseuse, but also for business user. If you are interested in knowing more details, please contact to discuss further. Feel free to share insights with us.