Civil photovoltaic power generation system is an important part of distributed power generation system. With the continuous improvement and implementation of domestic distributed policies, photovoltaic power generation has entered the life of ordinary people. Because the roof conditions of residents all over the country are different, Each project needs to be tailored to local conditions and customized design and construction. The author has had the privilege to participate in practical engineering cases and have a better understanding of the construction of small civil systems. This article takes the tile roof and concrete roof as an example, mainly introduces the design and construction part, for civil system practitioners or those interested in household distributed power generation.
1. Design of civil distributed generation system
The design of civil distributed projects needs to complete the roof survey and related information collection in the preliminary work, and provide the owner with the preliminary design plan or the roof power generation effect map. The effect map can explain the professional design ability from the side door on the one hand, and the other The aspect can be very intuitive to show the layout and real-time shadow of the components for the owner. Figure 1 and Figure 2 show the concrete roof support installation and component laying effect diagram. Figure 3 shows the distributed power generation of the villas in Nanjing based on the CAD drawings. The system's components are arranged to produce renderings. However, most villa roof owners may not have roof plans and elevation drawings. In this case, we only need to grasp the overall size of the roof, and the details are simplified. For civil system designers, I highly recommend SketchUp because of its excellent rendering and shadow analysis.
Figure 1 bracket SketchUp renderings
Figure 2 Concrete roof bracket installation and component laying SketchUp renderings
Figure 3 Villa distributed power generation system component layout SketchUp renderings
The important work before the project construction is to deepen the design, such as the specific arrangement of the square array, the installation plan of the bracket, the selection of components and inverters, the wiring and cable laying scheme, the installation position of the inverter and the AC distribution box, and the lightning protection grounding. Etc., the installation plan of the square array and the bracket is the key content. For the civil system, the installation design of the bracket is very flexible.
The roof of the villa is generally in the form of tile surface and concrete. The brackets and the roof are fixed with punching and load-bearing pressure blocks. For the hole punching, the roofing waterproofing project is involved because the structure of the original roof is destroyed.
Figure 4 shows the fixing method of the concrete roof expansion bolt and the roof and the waterproofing method of the roof. The diameter of the hole needs to match the diameter of the expansion bolt. It is too small and too large. The depth of the hole needs to be determined according to the structure of the roof. The depth of the expansion bolt is not allowed to exceed the casting layer. Generally, the maximum depth is about half of the cast-in-place layer, and this is used as the basis for selecting the length of the expansion bolt.
The roof waterproofing shown in Figure 4 uses triple waterproofing, that is, the black silicone or 995 structural adhesive used in the component package is filled in, the waterproof rubber pad is used between the roof and the angle aluminum, and the bolt mounting position is sealed with waterproof glue. For the tile roof, if the underlay is a cement concrete layer, the anchor is fixed by an expansion bolt, and the waterproof method can also be adopted.
Fig. 4 Fixing method of expansion bolt and roof on concrete roof and roof waterproofing measures
The design of the bracket needs to know the common rail model and accessories. Figure 5 shows the common bracket structure used for concrete roofing (the square array is composed of 2*4 pieces), which consists of beams, vertical beams, square tubes, angle aluminum, L legs, T-bolts and hexagon socket bolts, inner snap connectors, press blocks and other accessories, deepening the design needs to determine the type, size and quantity of each accessory.
The inner snap connector is used to connect the square tube and the vertical beam and the angle can be adjusted. The fixing between the vertical beam and the beam adopts the L leg and the M8 T-bolt. The square pipe and the roof are fixed by the expansion bolt and the L leg. The role of the angle aluminum is used for the oblique support and reinforcement.
Figure 5 Concrete roof bracket solution
Toaster, is a commonly used kitchen supplies, mainly used to bake bread. A toaster usually includes a multi-functional oven, a heat-insulating surface, a special lifting device, etc. The more advanced also includes a separable breadcrumb chassis. The toaster is a heating appliance. Its function is to generate enough heat in the vicinity of the bread to bake the bread. If there is no pop-up toaster, breakfast will certainly not be so rich nowadays.
In many families, the toaster is more prone to failure than any other small home appliance. There are two reasons for this. First of all, the toe machine manufacturing costs are generally very low, its quality is not high. You can replace a new device with just $ 10.
Second, the toaster is often not a problem when their own failure, but the food particles interfere with its normal operation. If there are too many slices of bread on the bracket, they will fall into the bottom of the toaster and accumulate when the movement of the tray will move up, thus hindering the movement of the bracket, causing the heating element to short circuit, Open the device and affect the function of the spiral tube.
Most of the pop-up toasters are equipped with a large debris plate and have a door at the bottom, the reason for this. By sliding or opening the broken door, you can clean up the food particles that accumulate at the bottom of the toaster.
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