What Are The Basic Types of Fixed Photovoltaic Brackets?

Introduction to fixed photovoltaic brackets：

The photovoltaic array does not rotate with the change of the solar incident angle, and receives solar radiation in a fixed manner. According to the inclination setting, it can be divided into: optimal inclination fixed type, sloping roof fixed type and adjustable inclination fixed type.

1. Optimal inclination fixed type: 

It means that the local optimal installation inclination is calculated first, and then the entire array is fixedly installed at this inclination. At present, this type of photovoltaic bracket is widely used in flat roof power stations and ground power stations.

(1) Flat roof concrete foundation bracket

The flat roof concrete foundation bracket is the most commonly used installation form in flat roof power stations. According to the form of the foundation, it can be divided into strip foundation and independent foundation; the connection method between the bracket support column and the foundation can be connected by anchor bolts or directly embedding the support column into the concrete foundation.

Advantages: Good wind resistance, strong reliability, and no damage to the roof waterproof structure.

Disadvantages: The concrete foundation needs to be made first and maintained to a sufficient strength before the subsequent bracket installation can be carried out, and the construction period is relatively long.

(2) Concrete ballast bracket for flat roof

Advantages: The construction method of concrete ballast bracket is simple. The bracket can be installed at the same time as the counterweight is made, saving construction time.

Disadvantages: The wind resistance of concrete ballast bracket is relatively poor. When designing the weight of the counterweight, the maximum wind force in the local area needs to be fully considered.

(3) Concrete foundation bracket for ground power station

There are many kinds of concrete foundation brackets for ground power station. According to the geological conditions of different projects, the corresponding installation method can be selected. The following mainly introduces the most common concrete foundation installation forms such as cast-in-place reinforced concrete foundation, independent and strip concrete foundation, and precast concrete hollow column foundation.

a. Cast-in-place reinforced concrete foundation

According to the different foundation forms, cast-in-place reinforced concrete foundation can be divided into cast-in-place concrete piles and cast anchor rods. Advantages: The cast-in-place reinforced concrete foundation has less excavation volume, less concrete steel bar, lower cost and faster construction speed. Disadvantages: The construction of cast-in-place reinforced concrete foundation is easily restricted by environmental factors such as season and weather, and the construction requirements are high. Once it is completed, it cannot be adjusted.

b. Independent and strip concrete foundations

Advantages: Independent and strip concrete foundations use reinforced extended foundations, which are simple to construct, have strong geological adaptability, and can be buried relatively shallowly. Disadvantages: Independent and strip concrete foundations require large engineering workloads, require a lot of manpower, require large amounts of earth excavation and backfilling, have long construction periods, and cause great damage to the environment.

c. Precast concrete hollow column foundation

Precast concrete hollow column foundations are widely used in hydro-photovoltaic complementary power stations, tidal flat power stations, and other power stations with poor geological conditions. At the same time, due to the advantage of foundation height, they are also widely used in mountain power stations and agricultural-photovoltaic complementary power stations.

(4) Ground power station metal pile brackets

Metal pile brackets are also widely used in ground power stations, and can be mainly divided into screw pile foundation brackets and impact pile foundation brackets.

a. Screw pile foundation brackets

Screw pile brackets can be divided into screw pile brackets with flanges and screw pile brackets without flanges according to whether they are equipped with flanges; they can be divided into narrow leaf continuous screw pile brackets and wide leaf interval screw pile brackets according to the shape of the cotyledons.

Screw piles with flanges can be used for single-column or double-column installation, while screw piles without flanges are generally only used for double-column installation.

The pull-out resistance of wide-leaf interval screw pile brackets is better than that of narrow-leaf continuous screw pile brackets. Wide-leaf interval screw pile brackets should be given priority in areas with strong winds.

b. Impact pile foundation brackets

The impact pile foundation bracket, also called metal fiber rod foundation bracket, mainly uses a pile driver to directly drive C-shaped steel, H-shaped steel or other structural steel into the ground. This installation method is very simple, but the pull-out resistance is poor.

Advantages: For metal pile foundations, steel piles are driven into the soil with a pile driver without excavating the ground, which is more environmentally friendly; it is not restricted by seasonal temperature and can be implemented under various climatic conditions including winter in the north; the construction is fast and convenient, the construction period is greatly shortened, and it can be easily relocated and recycled; the foundation is easy to adjust the height during the pile driving process.

Disadvantages: It is difficult to pile in areas with hard soil; it is easy to damage the galvanized layer when pile driving in areas with more gravel; the corrosion resistance is poor when used in saline-alkali areas.

2. Fixed type on sloping roofs

Considering that the bearing capacity of sloping roofs is generally poor, most of the components on sloping roofs are directly installed flat, and the azimuth and inclination of the components are generally consistent with the roof. According to the different sloping roofs, 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 roofs, also called color steel tile roofs, are mainly used in industrial plants, warehouses, etc. According to the different forms of color steel tiles, they can be divided into corner-relaxed light steel roofs, vertical lock-edge steel roofs and trapezoidal light steel roofs.

The corner-relaxed light steel roofs and vertical lock-edge light steel roofs mainly use clamps as connectors to fix the guide rails on the roof, while the trapezoidal light steel roofs need to use self-tapping bolts to fix the connectors on the roof.

Regardless of the type of roof, when selecting the connector, it is necessary to measure the "angle relaxation", "vertical edge" and "trapezoidal" dimensions on site to ensure that the connector matches the roof. When installing the trapezoidal light steel roof bracket, waterproof measures must be taken to avoid leakage at the bolt drilling holes.

3. Fixed tilt angle adjustable

The fixed tilt angle adjustable type means that at the turning point of the solar incident angle change, the fixed bracket tilt angle is regularly adjusted to increase the absorption of direct sunlight and increase the power generation with a slight increase in cost.