Most household and industrial and commercial PV modules are installed on the roof, which can not only help the owner save electricity, but also optimize the use of roof space. In this article, XINPUGUANG will discuss some of the most important things you must know about installing solar panels on a flat roof.
Key 1: which installation mode is used
PV modules are installed on different roofs in different ways. Common installation methods include additional type, ballast type and pile foundation type.
If the roof belongs to the color steel tile type, the additional type is generally considered, and the components are directly laid on the color steel tile. The color steel tile roof also has a certain inclination. Although it may not be the best inclination corresponding to photovoltaic power generation, the transformation cost caused by increasing the inclination also needs to be comprehensively considered. The cement roof is usually flat, and the common installation methods are ballast type and concrete foundation pile foundation type. The main purpose of the concrete foundation is to ensure that the support system remains intact even during the storm season. The utility model ensures good installation without causing water leakage on the roof, and can also improve the efficiency of solar cell modules and reduce the sunlight blocking by the parapet.
Key 2. Flat roofs do not represent tiled installations
It seems to be the most natural way to install PV modules on a flat roof by tiling. Not only can the installation amount / area be maximized, but also PV may be used as a roof ceiling to increase the space area. However, in fact, installing PV on a flat roof does not mean that you should also set its inclination to 0 degrees. We need to consider many factors and avoid flat installation, including: the flat components are easy to accumulate dust, which may cause 10% or even 30% of the power loss; Cleaning is more inconvenient, and the accumulated water is not easy to flow out; Compared with inclined installation, the power generation will be reduced; The investment return period will be longer; It may not be possible to remove the accumulated ash by natural rainfall;
Key 3. Wind speed must be considered for flat roof installation
At the design stage of the solar system, the maximum wind speed that may occur locally must be considered, especially in areas where the wind speed exceeds 180 kilometers per hour. The ordinary flat roof solar power generation system can withstand the wind speed of 160 km / h (level 13 typhoon). However, if there is no parapet for wind protection and no wind protection is considered between arrays, the instantaneous wind speed caused by air flow in local areas will be much higher than the actual wind speed. At this time, the selection of supports, structural design, ballast or concrete foundation strength design must rely on the recommendations of professional institutions. Even the tiling of color steel tile roofs should also have scientific analysis.
Key 4. Risk of water leakage from flat roof installations
Ponding is common on flat roofs. Because the roof is flat, there is no place for water to go, or the drainage is slow, and the time to stay on the roof will be long. Therefore, any gap or hole on the roof will become a place for ponding. At this time, for the flat roof with photovoltaic system installed, due to the possible damage to the waterproof layer caused by the installation of support and concrete pile foundation, it becomes the biggest water leakage risk of flat roof photovoltaic. If it is a color steel tile roof, it is better to use a fixture to install it than to punch holes in the color steel tile; If the colored steel tiles are not suitable for fixture connection, structural adhesive bonding is also an option. Zhejiang Lexus silicone has a relevant solution; If holes must be punched, ensure that all holes are properly sealed to prevent water.
Key 5. Mechanical units on flat roofs need to be considered
One of the challenges in designing and installing PV on cement flat roofs is the various mechanical devices on the roofs of existing buildings, such as outdoor air conditioning units, drainage pipes, exhaust fans, ventilation facilities, water tanks, railings, roof structures, HVAC systems and water pipes.
These existing equipment not only affect the layout of roof PV, but also affect the spacing and arrangement of tie brackets, and may also shadow the PV array, or affect the future operation and maintenance. Some designers will consider adding PV to these facilities to protect them from wind and rain. However, another problem arising from this is the high design requirements and wind protection requirements, as well as the difficulties of operation and maintenance. For roof facilities, the design can only be carried out according to local conditions, but this is an unavoidable problem that must be paid attention to.
The above are several key factors that should be paid attention to when investing in rooftop photovoltaic power stations. A little PV knowledge every day, and continue to pay attention to the XINPUGUANG official website:
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