At present, photovoltaic power generation systems with building roofs as carriers are more common. When designing and installing photovoltaic power plants on roofs, safety issues are very important, and reasonable design selection can bring cost savings and increased revenue.
Below, summarize the precautions for the installation of photovoltaic roofing.
First, determine the roof solar mounting type and roof conditions
Identifying the roof: The roof must first have a very intuitive judgment, that is, to identify the type of roof, whether it is a flat roof solar panel mounting or a sloping roof solar mounting, or a metal roof, and the solar mounting structure of the roof, which is concrete, tile, terracotta or exposed.
Judging roof construction conditions
1. Utilization area: Firstly, it is judged how much available area of the roof, because the available area directly determines the installed capacity of the photovoltaic system. Secondly, the orientation of the roof, the roof is best to face south, because we are in the northern hemisphere, the south is the highest power generation, the best solar radiation. It can also be slightly biased to the east or west, usually within a few degrees or about 10 degrees, and can be controlled within 1% of the power loss.
2, occlusion: occlusion is very important for the impact of solar power system, occlusion includes the blockage of the building, and there are no tall trees around the building affecting the lighting
3. Waterproof: Judging the waterproof condition of the roof is to see if there is a very good waterproof layer on the roof. If the building does not have a good waterproof system, the roof function may not be satisfied within the life cycle.
4. Type and anti-corrosion are the basic requirements for roofing: It is necessary to first judge whether the type of metal roof can be installed. Anti-corrosion is to pay attention to the anti-corrosion effect of anti-corrosion paint on metal roof.
5. Load-bearing: The photovoltaic system should be built on the roof. If the roof's carrying capacity can't meet the photovoltaic construction, this project is not established.
The photovoltaic system's own safety and building safety, including fire, lightning and maintenance access, to ensure effective protection of all contact points. The lightning protection should be integrated with the lightning protection of the building. The maintenance access is safe for maintenance and must be reserved.
Second, the slope roof photovoltaic system has a technical skill in installing the panel
1. The roof tile on the sloping roof serves as the decorative material for the roof, and the panel is hung on the roof. How is it hanging?
When the solar panel mounting structure is selected, there are two characteristics for the installation method: 1. The photovoltaic module is mainly installed on the slope. The photovoltaic array is laid in parallel with respect to the roof, and the bracket adopts a steel embedded part to form a fixed beam;
2. The vertical distance between the PV module installed on the slope bracket and the roof meets the requirements for installation and ventilation and heat dissipation (the overhead distance is generally 150~200mm).
The solar panel mounting bracket installation method should pay attention to the battens and the water strips connected to the fixed tiles. The second is the form of the tiling, because the terracotta is glued to the concrete through the concrete, there is no water strip, only through the concrete. As a new material, the roof of the shingle tile is gradually being used more, because the shingle tile is taken back and restored, and the water is leaked if it is not well controlled. Therefore, the way to use is to connect the fixed point to increase the connection position, and the oil felt tile has a certain thickness, so that a certain space is formed. Before and after fixing, it should be filled with sealant to avoid water leakage. Hidden dangers.
Third, the flat roof photovoltaic system waterproof layer is essential
The solar mounting structure selection of the flat roof can be selected according to the actual practice of the roof finish surface. The bracket system generally consists of four parts: the column, the foundation, the inclined beam and the beam. The battery assembly is connected to the beam by fasteners. (Weight: 0.35~0.50kN/m2)
Installation inclination angle: the inclination angle corresponding to the maximum value of the local annual total power generation is used as the installation inclination angle of the bracket (theoretical calculation value);
Common housing structure: cast-in-place concrete frame and floor slab, steel structure + cast-in-place concrete slab, brick-concrete structure + prefabricated slab;
Common roof finish: waterproof membrane, cement mortar protective layer, ceramic tile.
The flat roof PV solar panel mounting bracket is U-shaped steel, which is a thin thin-walled profile or an aluminum alloy profile. For these two materials, the steel profile has lower cost, high strength, stable structure and self-importance, and the aluminum alloy profile has high cost and light weight. Compared with the two types of cost, the steel profile is about 0.2 yuan/watt lower than the aluminum profile.
Fourth, color steel roof photovoltaic system steel plate type impact design
Color steel tiles are generally used in home factories or large industrial plants. The difference between its installation and the sloping roof is that the support is installed in a different way. The color steel roof is a fixture on the color steel plate, which is clamped on it for support. Its function is that the installation angle is installed along the slope of the roof. If the structural bearing capacity of the roof can be satisfied, the tilt angle can be tilted up and the installation angle can be increased. Common roofing systems, vertical occlusion, upright seaming systems, profiled sheet systems (single or sandwich).
In summary, PV roofing installation precautions include roof type and conditions for construction, as well as installation characteristics of different types of roofing, avoiding hidden dangers, selecting suitable materials, reducing costs, and expanding revenue.