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Photovoltaic stents comprehensive summary

2016/2/19      view:

 Photovoltaic stents comprehensive summary


     According to the German statistics, in a large-scale solar power station project, take the cost of pv projects with a total investment of about 21%, and solar photovoltaic stents investment accounts for only about 3% of the total cost. Solar power as a result, relative to the high investment, support cost fluctuation is not sensitive to factors, select high-end stents cost only increase by less than 1%, but the bracket is not appropriate, if choose the late maintenance cost increases, the overall consideration is not economical.

    Any type of solar photovoltaic components assembly parts, weather resistance is one of the most important features. Need to ensure that 25 years structure must be solid and reliable, able to withstand such as environmental erosion, wind and snow load and other external effects. The installation of the installation of safe and reliable, with the minimum cost to maximize the use of the effect, almost no maintenance, reliable maintenance, recycling, do all of these are options are important factors to consider. Has some support enterprises used the high wear-resisting material to resist wind snow load and other corrosive action, comprehensive use of aluminum alloy anodic oxidation, super thick hot dip galvanized, stainless steel, resistant UV aging technology to guarantee the life of the bracket of solar energy and solar energy tracking.

 A common form, photovoltaic stents

     Photovoltaic stents have multiple classification methods, such as welding and packaged in accordance with the mode of connection can be divided into according to the installation structure is divided into fixed and day by day, according to the installation site is divided into the ground and roofing, etc. No matter what kind of photovoltaic system, the bracket constitute a broadly similar, including all fittings, beams, columns, keel, auxiliary parts.

 1.1 fixed photovoltaic stents

     Fixed photovoltaic stents, just as its name implies, is refers to the installation position and Angle remains unchanged after stent system. Fixed installation directly place the solar photovoltaic modules towards low latitudes (into a certain Angle with the ground), in terms of series-parallel solar photovoltaic array, so as to achieve the goal of solar photovoltaic power generation. There are many types of the fixed way, such as ground fixed way is pile foundation (direct embedment method), concrete block breeding method, embedded, anchor, etc., level of fixed way according to the different roof materials have different solutions.

     The framework of the solar cell array, usually by coming out of the reinforced concrete foundation steel processed products of hot dip galvanized or stainless steel anchor bolt to fix. On the roof with concrete foundation, the building of waterproof layer uncovered part of peeling off surface of concrete, array on the patio of reinforced concrete reinforced welded together. Can't weld reinforcement, in order to use concrete adhesion and self-respect against the wind, makes a concrete base surface uneven adhesion. Later, with a waterproof filler secondary waterproof processing.

     If the above method can implement, can be laid on the waterproof layer is more expensive weatherability cushioning material such as silica gel, on which the installation of hot dip galvanized steel skeleton, the weight of the bracket and fixed on the steel skeleton array. Steel frame with plastic bolt connection in the room around prominent eaves wall pressure, the purpose is to not make the wind pressure array and steel skeleton movement. The secondary reinforcement.

 1.1.1 roof photovoltaic system support

     Photovoltaic roof support by the installation environment consists of the slope roof, flat roof, when installation should comply with the roof environment, does not destroy the intrinsic structure and waterproof system, roofing materials including glazed tile, caigang watts, compared with the concrete surface, etc. According to different roof materials with different support scheme

     According to the tilt Angle is divided into slope roof and plane two kinds, so the roof there are many kinds of choices, the tilt Angle of photovoltaic system for slope usually adopt to slope roof tile way to decorate, also can use the layout of the roof with a certain Angle and way, but this kind of practice is relatively complex, less case; On to the roof with tile and tilt Angle of two options.

     According to different roof materials, there will be a different bracket system.

 1) the glazed tile roof support

     Glazed tile hard soft materials such as alkali soil, purple sand after extrusion, plastic pressure fire of building materials, brittle material, the load bearing ability is poor. When installing stents in general and the special design of the main supporting components, glazed tile roof fixed lower to shore up support girder and beam, supporting artifacts, such as connection plate is usually designed to open hole style, flexible and effective implementation support position adjustment. Between components and beams using the aluminum gold pressing.

 2) caigang watts roof support

     Choi steel thin plate is cold-press or cold forming steel. Steel plate is made of organic coating thin steel plate (or color steel), galvanized sheet steel, anticorrosive steel sheet (contain asbestos asphalt layer) or other steel sheet, etc.

     Pressed steel plate with light weight, high strength, good seismic performance, rapid construction, the advantages of beautiful shape, is a good building materials and components, mainly used for retaining structure, floor, can also be used to other structures.

     Caigang watts roof generally divided into: vertical overlock, biting mouth (chi), card buckle type (dark buckle type), fixed connection (pin type).

     When caigang watts roof installation of photovoltaic system, caigang watts shape and its bearing capacity, should be fully considered to make sure the bracket. Caigang watts roof support fixed way according to main caigang watts shape.

 3) the concrete roof support

     Concrete roof photovoltaic stents are generally fixed Angle of fixed way, also can use flat out way. The roof fixed way mainly for concrete foundation and standardized fixed fittings, divided into cast-in-site type and precoat type in two ways.

     Based on cast-in-place concrete roof torque type, suitable for roofing load-bearing and roofing of small, high wind load region.

     Concrete roof placing precoat rectangular foundation, suitable for small roof load, wind load area and roof; Based on the rectangular prefabricated standardized fixed fittings.

 1.1.2 ground photovoltaic system

     Surface photovoltaic system refers to the installation site selection in the outdoor open the photovoltaic system, common large ground pv systems support fixed way as geology, environment, and climate factors and different. Generally adopt concrete bar (block) foundation forms (special gay love situation need consulting soil mechanics design professionals), also can use the way such as pile type, anchor block type.

     Different foundation forms can choose according to actual situation, the concrete method of weight and embedded parts often used in roof solar construction or renovation, such can effectively avoid destroying the roof membrane structure; Anchor method and directly buried type used in the construction of solar power, has the characteristics of stable, high reliability.

     Base construction according to construction experience, anchor method is the most strong, the highest security, but anchor and connection parts need special customized solar photovoltaic stents, cost is very high. Directly buried type, by contrast, construction is simple, only need to use the tapping machine hole and pour concrete at the scene, in the concrete before solidification will channel steel can be directly inserted into the hole, but compared with the method of anchor block, directly buried type based on the scene the independence requirements of the soil is higher, the need for early geological survey of the experiment. Of course, in the case of geology is guaranteed, also can not do preliminary geological exploration.

     Solar photovoltaic stents mainly depends on the configuration of main and second beam way panels placed method. In general, because the electricity under the premise of conditions allow, directly buried method is obviously superior to anchor method.

 1.2 tracking photovoltaic stents

     When the sun's rays is perpendicular to the battery panel, solar energy received solar maximum, power is the highest. But the earth all the time for revolution and rotation, so the sun's rays Angle change is all the time. And fixed bracket, for the battery panel is fixed, therefore does not guarantee as far as possible let the sun's rays, vertical panels can not make full use of solar energy.

     Tracking system is to aim at the sun as far as possible, so the sun's rays per unit area of the battery panel to receive more of the sun's rays, thus increasing output. Currently face, tracking system includes weekly tracking system with two major categories of two-axis tracking system, single axis tracking system is divided into horizontal axis tracking system and single axis tracking system.

 1.2.1 uniaxial trace level

     Level of single axle track suits in low latitudes, usually the height of the track the sun Angle to improve the vertical component of the sun's rays in the panels to increase its capacity. Level of single axis tracking system, not simply tracking Angle of the sun, but take a complex calculation algorithms, makes it the sun's rays to maximize the vertical component of the battery panel, to control its movement Angle. That maximize the increase of the photovoltaic power generation. Level of single axis tracking system is relative to the fixed bracket can increases from 20% to 30% before.

 1.2.2 inclined uniaxial tracking

   Oblique single shaft for latitude 30 degrees higher than the above, by a shaft Angle compensation latitude Angle. Then trace in the axis direction Angle of the sun, so as to achieve better with the increase of photovoltaic power generation. General relative to the fixed bracket can increase the output before the 25% to 35%.  

 1.2.3 two-axis tracking

     Two-axis tracking, there are two axis movement at the same time, so we can ensure that solar panels is always perpendicular to the sun's rays, so the two-axis tracking solar power generation efficiency is highest, can be increased by 35% to 45%.

 Second, the support material and selection

     Solar stent materials, the choice of the ways of installation, the strict calculation is needed to determine. In addition, the installation location of quality of a material, such as climate, environment factors, weather resistance is one of the choice of basis. A soft, such as the installation of the site can adopt the way of anchor is fixed, if the historical maximum wind speed or the amount of snow are within a certain range, you can choose appropriate can not only meet the requirements, lower cost and material.

     At present, solar stent materials mainly of aluminum alloy (Al6005 - T5 surface anodic oxidation), stainless steel (304), galvanized steel (Q235 hot galvanizing), etc., of which the following stainless steel material cost high, good weather resistance, high recyclable value;

     Aluminum alloy stent generally used in civil building roof solar energy application, aluminum alloy has the characteristics of corrosion resistance, light quality, beautiful and durable, but its bearing capacity is low, cannot be applied in large-scale solar power station project. The other aluminium alloy steel slightly higher than those after galvanizing.

     Galvanized steel bracket performance is stable, the affiliated technology mature, high bearing capacity, easy installation, widely used in civil, industrial, solar photovoltaic power station and the sun. Among them, the payments are factory production, uniform, stable performance and excellent anticorrosion performance, beautiful appearance. Be worth what carry is, only need to use special design fitting lacing can be channel steel, construction speed is fast, without welding, so as to ensure the integrity of the coating. The disadvantage of this kind of product is fitting process is complex, sort is various, for production and manufacturing, design requirement is high, so the price does not poor. Another disadvantage is that galvanized steel material recycling finally high value than the other two.

     By far the most commonly used for galvanized steel bracket, mainly adopts steel as main materials, the so-called steel is a kind of a certain section shape and size of strip steel, the main types of i-steel, channel steel, Angle steel, round steel, square steel, C steel, h-beam, etc.

    (1) the Angle can be according to the structure of the different needs of different kinds of stress components, also can make members between the joints. Widely used in various building structure and engineering structure, such as the beam, Bridges, transmission tower, lifting transportation machinery, ships, industrial furnace, reaction tower, container frame and warehouse shelves, etc. Angle is built with carbon structural steel, it is simple section steel, steel is mainly used for metal components and framework of workshop. In use requirement has good weldability, plastic deformation properties and mechanical strength. Production of Angle steel billet raw material for low carbon steel billet, finished Angle steel for hot forming, normalizing or hot rolling state delivery.

     (2) H section steel is a kind of cross section area allocation optimization and weight more reasonable than economic section effective profiles, because of its section with the English letter "H" is the same as the name. Since the different parts of h-beam with orthogonal configuration, so h-beam in all directions has bending capacity, simple construction, cost saving and structure light weight etc, and has been widely used.

     (3) C steel after hot rolling and cold processing and become, wall thin light dead weight, the cross section of good performance, high strength, compared with the traditional channel, equal strength can save 30%. C payments are widely used in steel structure building of purlin, wall beam, also can combine into a lightweight roof, bracket and other construction. In addition, can also be used for mechanical column, beam of light manufacturing and arm, etc.

     (4) rectangular pipe is a hollow strip steel, a large number of used for conveying fluid pipe, such as oil, rectangle tube gas, water, gas, steam, etc., in addition, in the high bending and torsional strength phase at the same time, lighter weight, it is widely used in the manufacture of machinery parts and engineering structures. Also commonly used for the production of various kinds of conventional weapons, barrel, shells, etc. Mainly used as beam in the pv stent system.


 Third, summary

     Bracket of solar photovoltaic power station is a very important part of it is bearing the weight of the power of photovoltaic power station main body, if the design is unreasonable, not disaster accident, climate is fatal to the influence of the power station. So in the design process, need comprehensive tutorials on various aspects factor, finally determine the support selection and array layout.