Summary of Experience in the Selection of Photovoltaic Supports

In a large-scale solar power plant project, the construction and installation cost accounts for about 21% of the total investment in photovoltaic projects, while the investment in solar photovoltaic brackets only accounts for about 3% of the total cost. Therefore, compared to the high investment in solar power plants, the fluctuation of bracket costs is not a sensitive factor, and the cost of choosing high-end brackets only increases by less than 1%. However, if the selected bracket is not suitable, the cost of later maintenance will greatly increase, and overall consideration is not cost-effective.

One of the most important characteristics of any type of solar photovoltaic module assembly component is its weather resistance. It is necessary to ensure that the structure is firm and reliable within 25 years, capable of withstanding environmental erosion, wind, snow loads, and other external effects. Safe and reliable installation, achieving maximum usage effect with minimal installation cost, almost maintenance free, reliable repair, and recyclability are all important factors to consider when choosing a solution. At present, some bracket companies have applied high wear-resistant materials to resist wind, snow, and other corrosive effects, and have comprehensively utilized aluminum alloy anodizing, ultra-thick hot dip galvanizing, stainless steel, UV aging resistance and other technological processes to ensure the service life of solar powered brackets and solar tracking.

1. Common forms of photovoltaic brackets

Photovoltaic brackets can be classified in various ways, such as welded and assembled according to their connection method, fixed and day to day according to their installation structure, and ground and roof based on their installation location. Regardless of the type of photovoltaic system, its bracket structure is generally similar, including connectors, columns, keels, beams, auxiliary components, and other parts.

1.1 Fixed photovoltaic bracket

Fixed photovoltaic bracket, as the name suggests, refers to a bracket system that maintains its orientation, angle, etc. unchanged after installation. The fixed installation method directly places the solar photovoltaic modules towards low latitude areas (at a certain angle to the ground), and forms a solar photovoltaic array in series and parallel to achieve the purpose of solar photovoltaic power generation. There are various fixing methods, such as pile foundation method (direct embedding method), concrete block weight method, pre embedding method, ground anchor method, etc. The roof fixing methods vary depending on the roof material.

Ground support fixation method

The bracket of a solar cell array is usually fixed by steel hot-dip galvanized processed products or stainless steel anchor bolts protruding from a reinforced concrete foundation. When using a concrete foundation on the roof of a house, remove a portion of the waterproof layer of the house and peel off the concrete surface. Weld the steel bars of the concrete base used for the array together on the steel bars of the courtyard. When steel bars cannot be welded, in order to use the adhesion and self weight of concrete to resist wind pressure, the surface of the concrete base is uneven, which increases the adhesion. Afterwards, use waterproof fillers for secondary waterproofing treatment.

If the above methods cannot be implemented, expensive weather resistant cushioning materials such as silicone can be laid on the waterproof layer, and a heavy hot-dip galvanized steel skeleton can be installed on it, and then the array bracket can be fixed on the steel skeleton. The steel skeleton is connected to the protruding eaves wall around the house using plastic bolts. The purpose is to prevent the array and steel skeleton from moving due to wind pressure. Serve as an auxiliary reinforcement.

1.1.1 Roof photovoltaic system support

The installation environment of roof photovoltaic brackets includes sloping roofs and flat roofs. When installing, it is necessary to comply with the roof environment, without damaging the inherent structure and self waterproofing system. The roof materials include glazed tiles, colored steel tiles, asphalt felt tiles, concrete surfaces, etc. Different support schemes are adopted for different roof materials.

Roofs can be divided into two types according to their tilt angles: sloping and flat. Therefore, there are multiple options for the tilt angle of the photovoltaic system on the roof. For sloping roofs, they are usually laid flat to conform to the slope of the roof, or they can be arranged at a certain angle to the roof. However, this approach is relatively complex and there are few cases; For flat roofs, there are two options: tiling and tilting at a certain angle.