With the popularity of photovoltaic, how to improve the return on investment of power plants has become a concern, and the refinement of power plant design is gradually on the agenda. There are two types of module layout in PV power plants, horizontal and vertical, and each has its own considerations regarding the use of horizontal or vertical rows depending on the situation. Which arrangement is more suitable for your home?
What are horizontal and vertical rows of modules?
As the name implies, horizontal module row means that the module is mounted on the bracket with the long side parallel to the east-west direction, while vertical module row means that the short side is parallel to the east-west direction. At present, there are more power stations with vertical arrangement, mainly because it is easy to install in vertical arrangement, while in horizontal arrangement, the top piece is more difficult to install, which affects the construction progress.
How to choose the layout
1. Flat ground power station
In a relatively flat ground power station, during a period of time when the sun rises and sets, it will happen that the front row of components shade the back row in parallel. After discounting the scattering and reflection factors, we estimate the horizontal row by 10 minutes less shading than the vertical row in the morning and evening. Considering that the irradiance decreases when the sun rises and sets, the calculation is based on the output power being 15% of the maximum output power. For a power station with 1500 hours of annual utilization, the horizontal row generates 1.2% more power than the vertical row.
2. Mountain, slope photovoltaic power station
Now photovoltaic power station and agriculture, forestry combined with more, inevitably in the mountains, slopes and other uneven terrain construction, then the complex terrain component layout how to choose it?
For the use of the southern slope of the mountain and the northern slope of the construction of power plants, similar to flat land, horizontal row is better than vertical row.
For power plants built using part of the east and west slopes, when the sun rises in the morning, the east slope shines first and the west slope is shaded. As the sun gradually rises and moves south, the west slope gradually shines to the sun and the east slope is shaded, and it can be seen that the shading is still roughly parallel to the long side of the components. The sun moves between the north and south regression lines, photovoltaic power plant areas north of the regression line, so qualitatively speaking, in mountainous areas, sloping areas and other irregularities, the ability of the components to resist shading in horizontal rows is greater than vertical rows.
3. Distributed roof, when there is shading around
For distributed photovoltaic power plant installed on the roof, if it is open without shade and has a tilt installation, the same as the ground power station. For there are poles or antennas and other vertical shading, and can not be avoided, if there is more shading can be considered for vertical installation. Of course, you can choose the way that suits your home according to latitude, roof orientation, area, tilt angle, etc., or a combination of both.
The effect of shading on the power of cells in horizontal and vertical rows
The characteristics of the module circuit structure determine the difference in the module’s ability to resist shading. Since shading is mostly near the ground, let’s take the example of 2 rows of cells near the ground being shaded to illustrate the impact of shading on power generation performance.
In the figure below, when the bottom two rows of cells of a module are shaded and arranged horizontally, the bottom bypass diode is on and the top two rows of cells continue to have power output. When the bottom two rows of cells of a module are blocked and arranged vertically, each of the cells in the module is blocked and the circuit is broken, and all 3 rows of cells have no power output.
When the sun rises and sets, module shading is present, which theoretically proves that the module is more resistant to shading in horizontal rows.
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