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# How to Calculate Solar Panel Tilt Angle

29 August 2018
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When installing a solar lighting system or any system that take its power from the sun, the first question that comes to mind is what will be the direction of the solar panel and its angle. The solar panel will operate at peak efficiency when fully directed to the sun. So, which direction should we position the solar panel?

When we look around, we can see solar panels that look at different directions from a different angle of inclination. This shows that there is a lack of information about which way the solar panel will look at, and how far it is inclined.

It may seem a simple idea that direct the solar panel to the sun. But we should keep in mind that the sun is located in different positions in different time zones during the year. During the day, the place is constantly changing. Therefore, it is necessary to calculate an optimal tilt angle.

The direction of the solar panel is determined by the location where the system will be installed. In countries like Turkey in the northern hemisphere, the solar panel is directed towards the south. In the countries located in the southern hemisphere, it is directed towards the north. Applications that we are used to seeing in our country (Turkey), where the solar panel is directed to the east or west are wrong. In every city of our country, the solar panel should face to the south.

When placed with an optimal tilt angle, the solar panel takes maximum solar power throughout the day. The angle of the solar panel depends on your location and at what time of the year you are. However, this article will show calculations for the fixed solar panel angle that can be used throughout the year. So, once you set the angle of the solar panel, you’ll be able to use it all year round without touching the system.

Solar panel tilt angle is calculated by the latitude value. This angle is multiplied by 0.87 if the latitude value is less than 25. If the latitude value is between 25 and 50, it is multiplied by 0.87 and added 3.1 degrees to the result. Turkey is among the 36-42 degree latitudes, this calculation method should be used for all installations in our country. The ideal angle can be obtained at approximately 45 degrees if the latitude value is 50 degrees and above.

You can use the following formula to calculate the angle of inclination of solar panel for use in all cities in Turkey.

Solar Panel Tilt Angle = Latitude x 0,87 + 3,1

The angle of inclination to be found with the help of the calculation is the angle between the panel and the floor. This means that the zero-degree panel inclination represents full horizontal positioning. 90-degree panel inclination represents full vertical positioning.

Latitude value of your location can be easily found using Google Maps. Select a point on the map, and Google will show you latitude and longitude. The first of the two numbers separated by commas is latitude.

For example, let’s make a calculation for Ankara. The latitude and longitude value for Ankara is 39.911817, 32.809245. The calculation can be done as follows.

39,9 x 0,87 + 3,1 = 37,8

As a result of this calculation, it can be said that the solar panel should be directed to the north at 38 degrees angle for use throughout the year in Ankara position.

The latitude and longitude value for Istanbul is 41.0082376, 28.9783589. The calculation can be done as follows.

41 x 0,87 + 3,1 = 38,8

In other words, the solar panel in Istanbul should have an inclination angle of 39 degrees. For Izmir it is 37, for Antalya 35 and for Trabzon it will be 39 degrees

All of the above calculations were made according to the fixed panel tilt angle throughout the year. You can use the solar panel at a fixed angle throughout the year. Also, you can do separate calculations for summer and winter seasons and change the solar panel angle of inclination throughout the year.

There is a special reminder for the winter. If there is snow in your area, you can prevent the accumulation of snow by increasing tilt angle of the solar panel. By this way, you can take more advantage from the sun.

Written by Emre Yılmaz – Aydınlatma Portalı, Asya Traffic Inc.