Yash
The tilt and the azimuth angle play a significant role in the efficient functioning of the solar power system.
You might have the most efficient solar panels attached with the most advanced inverter.
Also, your system might be rightly sized and capable of producing enough energy to meet your demands.
But all this would be in vain if your solar panels are not given the right tilt and the azimuth angle.
Incorrect values of these 2 parameters result in less energy production.
Angle of Elevation
When looking up at an object, it is the angle between the horizontal plane and the line of sight.
It is a way to find the tilt of the solar panels.
The angle of elevation in the above picture is 25°. Let’s place a solar panel flat on the ground and observe how the sun’s rays fall on its surface.
The sunrays graze over the surface of the solar panel, making an angle of 25 degrees.
Tilt of solar panels
The grazing sunrays are less intense than the ones falling straight (90°) over the solar panel’s surface.
To make the solar panel absorb the maximum sunlight its surface is kept perpendicular to the sun rays.
To make this happen, the rear side of the solar panel is given a tilt of 65 degrees with the ground.
Therefore, the right tilt can be found by subtracting the value of the elevation angle from 90 degrees.
When the sun is overhead, the sun rays fall straight over the surface of the solar panel. In that case, the tilt is zero.
However,
- I cannot find the elevation angle just by looking at the body. This is practically not feasible.
- This practice may lead to inaccurate results and hence the incorrect tilt of the solar panels.
- There is a solution, the latitude of the location.
What are Latitudes?
Latitudes are the imaginary lines that specify the north-south position of a point on the Earth’s surface in degrees. The equator at 0° latitude, the North Pole at 90° north, and the South Pole at 90° south. Lines of latitude, often called parallels, run parallel to the equator.
Let us look at the latitudes of some locations around the world.
How is the latitude of any location related to the tilt of the solar panels?
Well, for the fixed-tilt residential solar power system, the tilt value is equal to the latitude of the location where it is installed.
If you are living on the equator and interested in installing solar panels.
The solar panels are given a fixed tilt of 0° to receive most of the sun’s rays.
The formula is simple:
The tilt of the solar panels = latitude of your location
When the latitude is 23 degrees, the tilt is also 23 degrees.
When it is 46 degrees, the tilt of the solar panels is also 46 degrees to get the maximum sunlight.
The Earth’s axis is tilted
The rotation axis of the earth is tilted by 23 degrees.
Because of this tilt, the sunlight intensity is not maximum only at the equator throughout the year, rather it spreads from -23 to +23 degrees.
Point A on the equator may not receive the maximum sunlight throughout the year due to the rotational axis tilt of the Earth.
When the Earth revolves around the sun, at some point, the sun’s rays are maximum at point A on the equator.
As the Earth changes its position while revolving, the point on Earth B receives the maximum sunlight.
Also, while moving around the sun another point C on the Earth receives the maximum sunlight.
All this is happening due to the tilt of the earth’s rotation axis.
The region of the maximum sunlight intensity throughout the year can be represented as follows:
Due to this rotation axis tilt, the sunlight intensity varies throughout the year.
Let us find the solar panel tilt values at the different latitudes of the Earth.
Case 1: When the sun’s rays are falling straight on the equator
In this case, people living on the equator should keep their solar panels flat on the ground to get the maximum sunlight.
People living on a latitude of 23° should give their solar panels a tilt of 23° to get the maximum sun rays.
Similarly, for those living on the 46° latitude, a solar panel tilt of 46 degrees is required to absorb the maximum sunlight.
It can be represented in the picture as follows:
When the relative position of the Earth and the Sun changes. The sunlight intensity is now maximum on a latitude of 23 degrees.
However, we placed our solar panels according to the situation when the sunlight intensity was maximum at the equator.
Now our solar panels might not be getting the straight sunlight on the solar panels.
The situation can be depicted as follows:
Here we need to adjust our solar panels to the new tilt to get the maximum sunlight intensity.
Case 2: When the sun’s rays are maximum on the latitude of 23 degrees
Case 3: When the sunlight intensity is maximum on latitude -23 degrees.
There is a problem:
To get the maximum sunlight I need to keep changing the tilt of my solar panels.
It is very cumbersome, time-consuming, and a costly affair too.
We need to find the solution:
This problem can be solved by installing the solar trackers. These machines track the sun’s position and align the solar panels accordingly to get the maximum sunlight.
But the trackers add to the cost of the system.
These are cost-effective for large commercial solar projects.
For residential solar systems, the solar panels are given the fixed tilt.
Which is the latitude of the location where they are installed.
The Azimuth Angle
The azimuth angle describes the sun’s position in the sky relative to a specific point on the Earth’s surface. It is measured in degrees and represents the compass direction from which the sunlight is coming at any given time. Typically, the azimuth angle is measured clockwise from true north, with north being 0°, east at 90°, south at 180°, and west at 270°. Understanding the azimuth angle is crucial for optimizing the orientation of solar panels to maximize energy collection. By accurately calculating and adjusting for the azimuth angle, solar energy systems can capture the most sunlight throughout the day, enhancing their efficiency and effectiveness.
For solar panels in the northern hemisphere, the ideal azimuth angle is typically due south (180 degrees), while in the southern hemisphere, it’s due north (0 degrees). Adjusting the azimuth angle can significantly impact the amount of solar energy captured, especially in regions where the sun’s path varies seasonally.
By aligning solar panels to the optimal azimuth angle, one can maximize exposure to sunlight throughout the year, leading to better performance and increased energy generation. It’s important to consider local geographical and environmental factors, such as shading from buildings or trees, when determining the best azimuth angle for solar installation.
Understanding Azimuth Angle
The sun’s trajectory is from east to west.
For people living in the Northern Hemisphere, when they look towards the south, they can observe the trajectory of the sun.
To get the maximum sunlight over my solar panels throughout the day, I need to align their base parallel to the equator line.
This orientation would be most suited for my solar panels.
To find the Azimuth angle of my solar panels,
I will measure the angular distance from the North toward the normal line drawn perpendicular to the surface of the solar panels.
The azimuth angle in that case would be 180 degrees.
Let’s say I change the base line of my solar panels and place them slightly not parallel to the equator line.
In that case, during the noon time (when the sun is mid-way between the east and the west) the sun rays are not straight over my solar panels. They are grazing over their surface.
It means my solar panels are getting the maximum sunlight in the noon time.
However, there is a time when the sunlight falls straight over the surface of the solar panels and this time is before noon.
It can be shown as follows:
The sun rays of the red sun before noon fall straight over the surface of my solar panels.
This gives my solar panels maximum sunlight in the first half but the value decreases more in the latter half.
Then what is the ideal Azimuth angle?
For uniform energy production, the ideal azimuth angle is 180° for people in the Northern Hemisphere and 0° for the Southern hemisphere.
In case, you want more energy production in the daytime and less afternoon, then shifting the azimuth angle slightly less than 180° for people of the northern hemisphere and less than 0° for solar panels installed in the southern hemisphere would be fine.
Conclusion
The ideal position of the solar panels is defined by:
- Tilt
- Azimuth
For residential solar systems, the solar panels are given the fixed tilt which is the latitude of the location where they are installed.
For uniform energy production, the ideal azimuth angle is 180° for people in the Northern Hemisphere and 0° for people in the Southern Hemisphere.
In case, you want more energy production in the daytime and less afternoon, then shifting the azimuth angle slightly less than 180° for the people of the northern hemisphere and less than 0° for solar panels installed in the southern hemisphere would be fine.
