sloping roof fixed
Considering that the bearing capacity of the inclined roof is generally poor, most of the components on the inclined roof are directly tiled and installed, and the azimuth and inclination of the components are generally consistent with the roof. According to the difference of inclined roof, it can be divided into tile roof installation system and light steel roof installation system.
1) Tile roof installation system
The tile roof installation system is mainly composed of hooks, guide rails, pressure blocks and bolts and other connectors.
2) Light steel roof installation system
Light steel roof, also called color steel tile roof, is mainly used in industrial plants, warehouses, etc. According to the different forms of color steel tiles, they can be divided into angle-slack light steel roofs, upright seamed steel roofs and ladder light steel roofs.
Angle-relaxed light steel roofs and standing seam light steel roofs mainly use clamps as connectors to fix the guide rails on the roof, while ladder light steel roofs need self-tapping bolts to fix the connectors on the roof.
No matter which type of roofing is used, when selecting connectors, you must measure the dimensions of "angle slack", "upright edge" and "trapezoid" to ensure that the connectors match the roof. Take waterproof measures to avoid water leakage at the bolt holes.
3. Fixed inclination adjustable
The fixed inclination adjustable type refers to regularly adjusting the inclination of the fixed bracket at the turning point of the change of the incident angle of the sun to increase the absorption of direct sunlight and increase the power generation with a slight increase in cost.
Tracking photovoltaic support
The tracking photovoltaic bracket makes the photovoltaic array move with the change of the incident angle of the sun through electromechanical or hydraulic devices, so that the sunlight can directly hit the module panel as much as possible and improve the power generation capacity of the photovoltaic array. According to the number of tracking axes, it can be divided into: single-axis tracking system and dual-axis tracking system.
1. Flat single axis tracking system
Photovoltaic square arrays can track the sun with a horizontal axis in the east-west direction, so as to obtain greater power generation, and are widely used in low-latitude areas. According to whether there is an inclination in the north-south direction, it can be divided into standard flat uniaxial tracking type and flat uniaxial tracking type with inclination angle.
2. Inclined single axis tracking system
The tracking axis rotates in the east-west direction while setting a certain inclination angle to the south, and rotates around the inclination axis to track the azimuth of the sun to obtain greater power generation, which is suitable for use in higher latitudes.
3. Dual axis tracking system
Two axis rotation (vertical axis, horizontal axis) is used to track the sun rays in real time to ensure that the sun rays are perpendicular to the panel surface of the module at every moment, so as to obtain the maximum power generation, which is suitable for use in various latitudes.
4. Comparison of several bracket operation modes
Comparison and selection of photovoltaic support steel and aluminum
material strength
The bracket is generally made of Q235B steel and aluminum alloy extruded profile 6063 T6. In terms of strength, 6063 T6 aluminum alloy is about 68%-69% of Q235 B steel, so generally steel is better than aluminum alloy in strong wind areas and large spans. Profiles.
Deflection deformation
The deflection deformation of the structure is related to the shape and size of the profile and the elastic modulus (a parameter inherent to the material), and has no direct relationship with the strength of the material.
Under the same conditions, the deformation of aluminum alloy profiles is 2.9 times that of steel, and the weight is 35% of that of steel. In terms of cost, under the same weight, aluminum is 3 times that of steel. Therefore, steel is generally better than aluminum alloy profiles in strong wind areas, relatively large spans, and cost.
Anti-corrosion
At present, the main anti-corrosion method of the bracket is hot-dip galvanized steel with 55-80 μm, and aluminum alloy with anodized 5-10 μm.
The aluminum alloy is in the passivation zone in the atmospheric environment, and a dense oxide film is formed on the surface, which prevents the surface of the active aluminum substrate from contacting the surrounding atmosphere, so it has very good corrosion resistance, and the corrosion rate increases with time. and decrease.
Under ordinary conditions (C1-C4 environment), the thickness of 80μm galvanized steel can be guaranteed to be used for more than 20 years, but in high humidity industrial areas or high salinity seaside or even temperate seawater, the corrosion rate is accelerated, and the amount of galvanizing needs 100μm, above and require annual regular maintenance.
Aluminum alloys are far superior to steel in terms of corrosion resistance.
Other aspects compared to anti-corrosion aspects
(1) Appearance:
There are many surface treatment methods for aluminum alloy profiles, such as anodizing, chemical polishing, fluorocarbon spraying, electrophoretic painting, etc. It has beautiful appearance and can adapt to various environments with strong corrosive effect.
Steel is generally hot-dip galvanized, surface spraying, paint coating and other methods. The appearance is worse than that of aluminum alloy profiles. It is also inferior to aluminum profiles in terms of corrosion resistance.
(2) Section diversity
The general processing methods of aluminum alloy profiles include extrusion, casting, bending, stamping, etc. Extrusion production is the current mainstream production method. By opening the extrusion die, profiles of any arbitrary cross-section can be produced, and the production speed is relatively fast.
Steel is generally rolled, cast, bent, stamped and so on. At present, rolling is the mainstream production method for producing cold-formed steel. The section needs to be adjusted by the rolling wheel set, but generally, the machine can only produce similar products after finalization, and the size can be adjusted, but the section shape cannot be changed, such as C-section steel, Z-section steel and other sections. The rolling production method is relatively fixed and the production speed is relatively fast.
material recycling
The maintenance cost of the steel structure increases by 3% every year, while the bracket of the aluminum structure hardly needs any maintenance and maintenance, and the aluminum material still has a 65% recycling rate after 30 years, and the aluminum price is expected to increase by 3% every year. After 30 years, it is basically a pile of scrap iron with no recycling value.
Comprehensive performance comparison
(1) The aluminum alloy profile is light in weight, beautiful in appearance and excellent in corrosion resistance. It is generally used in household roof power stations and strong corrosive environments that require load-bearing.
(2) The steel has high strength and small deflection and deformation under load. It is generally used in ordinary power stations or components with relatively large forces.
(3) Cost: In general, the basic wind pressure is 0.6kN/m2, the span is less than 2m, and the cost of the aluminum alloy bracket is 1.3-1.5 times that of the steel structure bracket. In the small-span system, (such as color steel plate roof) aluminum alloy brackets and steel structure brackets have a relatively small cost difference, and aluminum alloys are much lighter than steel brackets in terms of weight, so they are very suitable for home roof power stations.
