Which is the Best Angle to Keep Solar Panel for Getting High Efficiency?

Everyone knows that the power of solar panels comes from the light emitted by the sun, and solar panels are equivalent to a conversion tool between light energy and electrical energy. In a fixed period of time, how much light energy the solar panel can absorb will directly affect the amount of electricity generated by the solar panel, and then affect the amount of electricity used by people. The cheapest way to make solar panels continuously and stably generate electricity (the following figure has clear influencing factors) is to find the best installation angle and the best inclination during installation.

Below we will talk about the best angle and the best inclination for the installation of solar panels, as well as how to identify the best angle for the installation of solar panels.

The best installation angle of solar panels

1.Panel direction

When installing solar panels, you generally choose to install them on the roof, and there are two types of roofs, flat roofs and pointed roofs. Their installation methods are different, because the panels are easy to lay flat when they are flat roofs. Excessive accumulation of water leads to the problem of reduced conversion rate of the panel. Generally, inclined frames are added when installing on a flat roof to solve the problem of excessive accumulation of water. The spire is divided into two oblique sides, and most houses have a slope of about 30-50.

Although the installation method is different from the installation environment, it does not affect the orientation of the installation panel at all. Therefore, we must know which side of the panel should face the solar radiation to generate more electricity. Because solar panels have higher conversion efficiency when the solar light is perpendicular to the surface of the solar panels, the best direction in the United States is an azimuth angle of 180° from east to south. On the contrary, in the southern hemisphere countries (such as South Africa and Australia), the best direction is an azimuth angle of 180° west to south.

When installing, the panel orientation encounters some obstacles (referring to objects that block light), you can change the angle of the panel slightly, then move it or remove the obstacles directly.

The solar panels can only face up to 45° due to the south (southeast and southwest). If it exceeds, energy output may be reduced by 2%-5%, so the direction and angle of the panel is very important.

2. Optimal tilt

We all know that the panel is facing south, so we also need to find the best inclination angle.

The inclination angle is the angle between the plane of the solar panel and the horizontal ground, and it is hoped that this included angle is the best inclination angle for the solar panel in a year when the power generation is maximum. The best tilt angle in a year is related to the local geographic latitude. When the latitude is higher, the corresponding tilt angle is also large. However, like the azimuth angle, the design should also take into account the restriction conditions of the inclination angle of the roof and the inclination angle of snow falling (the slope is greater than 50%-60%). With regard to the slope angle of snow fall, the total annual power generation may increase even when the amount of power generation is small during the snow accumulation period. Therefore, especially in grid-connected power generation systems, snow fall is not necessarily prioritized. , And other factors must be further considered. For true south (azimuth angle is 0°), when the tilt angle is gradually transitioning from horizontal (tilt angle is 0°) to the best tilt angle, its insolation will continue to increase until the maximum, and then increase the tilt angle. The amount of solar radiation continues to decrease. Especially after the inclination angle is greater than 50°-60°, the solar radiation will drop sharply, until the final vertical placement, the power generation will drop to a minimum. There are practical examples for the square matrix from vertical placement to 10°～20° oblique placement. For the case where the azimuth angle is not 0°, the value of the slope insolation is generally low, and the value of the maximum insolation is near the inclination angle close to the horizontal plane. The above is the relationship between the azimuth angle, the inclination angle and the power generation. For the specific design of the azimuth and inclination angle of a square array, it should be further considered in combination with the actual situation.

The most ideal inclination angle is to make the annual power generation of solar panels as large as possible, and the difference in power generation in winter and summer is as small as possible. Generally, the local latitude or local latitude plus a few degrees is taken as the inclination angle of the local solar cell module installation. Of course, if you can use computer-aided design software, you can optimize the calculation of the solar tilt angle, so that the two can be taken into account, which is especially important for high latitude areas. In high latitudes, there is a big difference in the amount of horizontal solar radiation between winter and summer. For example, the difference between Colorado and Florida is about 5 times. If the design is performed according to the horizontal plane radiation parameters, the storage capacity of the battery in winter is too large, resulting in an increase in the design capacity and investment of the battery. The optimal tilt angle is selected, the difference between winter and summer radiation on the solar cell surface becomes smaller, the capacity of the battery can also be reduced, and an equilibrium is obtained, which reduces the cost of the system and makes the design more reasonable.

If there is no condition for computer optimization of the tilt angle, the tilt angle of the solar cell can be roughly determined according to the local latitude:

When the latitude is 0°~25°, the inclination angle is equal to the latitude;

When the latitude is 26°~40°, the inclination angle is equal to the latitude plus 5°~10°;

When the latitude is 41°~55°, the inclination angle is equal to the latitude plus 10°~15°;

When the latitude is above 55°, the inclination angle is equal to the latitude plus 15°~20°.

However, different types of solar photovoltaic power generation systems have different optimal installation inclination angles. For example, photovoltaic power generation systems powered by seasonal loads such as light-controlled solar street lamp lighting systems. The working hours of such loads vary with the seasons, and their characteristic is that natural light determines the length of the load's daily working time. In winter, the sunshine time is short and the solar radiation energy is small, while the load working time at night is long and the power consumption is large. Therefore, the system design should consider taking care of the winter, and determine the inclination angle that can obtain the maximum power generation in winter, and the inclination angle should be larger than the local latitude angle.

U.S. light distribution map

How to identify the best angle of solar panel installation

1. The formula for generating electricity from solar panels

From the above formula, it is not difficult to see that the effective sunshine and the power of the solar panels determine the daily electricity generated by the solar panels. According to the data released by the US Meteorological Network, we can see that the effective sunshine has a lot to do with the region (not considered here for the time being, Haze, dust and other weather), for example: if a 100 watt solar panel is installed in New York, according to the data given by the New York Meteorological Network is 2 hours of limited sunshine, then the amount of electricity generated in a day when the electricity is ideal is 200 watt-hours, but if installed in Washington, according to the data given by the Washington Meteorological Network, it is 4.8 hours of limited sunshine, then the electricity generated in an ideal situation in a day is 480 watt-hours; therefore, we cannot artificially change the effective sunshine. , So we only use the actual power of solar panels to ensure the actual daily power generation.

Solar panel power = solar panel voltage * solar panel current

Everyone knows that the nominal power of solar panels is fixed, but in actual use, due to various reasons, the actual power of solar panels is far less than the nominal power. For example, a panel with a nominal voltage of 18V and 100W is optimal The actual maximum current under the solar radiation effect should be 100W/18V=5.56A. This data 5.56A can be used to distinguish whether the installation angle and position of the solar panel are correct, and it is also to distinguish whether the solar energy you have purchased is sufficient.

2. How to identify the installation angle of solar panels

Assuming that the power of the solar panel meets the requirements, then judging the maximum short-circuit current is to determine whether the installation angle and position of the solar panel are correct, then how to detect the maximum short-circuit current of the solar panel.

Test environment: sunny weather, strong sun and unobstructed

Test time: 12 o'clock to 14 o'clock noon

Step 1: Prepare a clamp-on ammeter.

Step 2: Short-circuit the positive and negative poles of the solar panel.

Step 3: Clamp the clamp meter to one of the wires (both positive and negative are ok).

Step 4: Move the solar panel at will to find the position of the solar panel when the maximum short-circuit current is found.

Step 5: Measure the angle and position of the solar panel at this time, it is the best position.

Do you think it's over? Let’s talk about portable solar panel. In fact, there’s nothing to say about portable foldable solar panel because they don’t need to be installed. You just need to open them and place them in a sunny place. The reason for the movement, so there is no need to worry about the conversion rate. The installation angle does not have a great impact on many portable foldable solar panel. The more important thing is the material of the product. For example, our ITETHIL monocrystalline silicon solar panel have a conversion rate of 23%, while polycrystalline silicon solar panel have a conversion rate of up to 18%. You can refer to this video: