Solar Panel tilt angle and Methods to calculate it

Solar Panel Tilt angle

The solar panel tilt angle is defined as the slope angle at which solar panels are mounted to the face of the sun. The tilt angle of solar panel depends upon latitude of installation of site, time of year when energy generation is most critical, desired level of energy output.

• When the tilt angle of solar panel is set equal to latitude of the site, the solar panel generates maximum the annual energy output. 
• The recommended tilt angle of solar module structure to minimize wind pressure is < 15 degree for flat surface. 
• However, minimum tilt of 10 degree should be maintained for natural cleaning of solar panel.

• The PV array should face towards true south (in the northern hemisphere) as ideal orientation, however, for structural uniformity and to accommodate more solar array in limited RCC flat roof space, orientation could be aligned with roof orientation. 
• The solar PV modules/panels should be installed at the same tilt angle as that of orientation of the roof for inclined roof. Solar PV module should be installed south facing in the northern hemisphere and north facing in the southern hemisphere. 
• As India is in the northern hemisphere, the solar panel modules will be always installed south facing. 
• The direction of north south can be determined by using magnetic compass.

Ideal Tilt Angle for Solar Panel

• The ideal tilt angle for solar panel is determined by how far your panel from the equator. 
• The angular distance of your panel location from the equator is known as latitude. 
• The Latitude increases as we move away from the equator, towards the poles therefore the tilt angle increases as we move from equator to North Pole or South Pole. 
• Counties which are closer to equator have lower tilt angle. 
• The tilt angle on the equator is 0 degree and 90 degree on the poles. The latitude angle is ideal tilt angle for solar panel.

Methods of Calculating Tilt Angle

• In order to get maximum power output from solar panel, best way to install solar panel facing south if your country lies in the northern hemisphere or north if it lies in the southern hemisphere. 
• The sun position in the sky changes as per geographic locations, the solar panel orientation and tilt angle need to be adjusted accordingly. 
• The sun position at comparatively lower in winter as compared with summer season.

Method 1

Solar panel tilt angle is equal to latitude of site

Method 2

The tilt angle is kept at 15 degree minus latitude of site for summer and warmer months whereas tilt angle is kept at 15 degree plus latitude of site for winter and cooler months.

Summer tilt angle calculation = Latitude – 15 degree

Winter tilt angle calculation = Latitude + 15 degree

Method 3

Find out latitude of your location

Summer tilt angle calculation = 0.69 × Latitude + 3.7

Winter tilt angle calculation = Latitude + 10

Yearly tilt angle calculation = (Summer angle + Winter angle) / 2

Case Study on Solar Panel Tilt angle

A solar panel technician wants to install solar panel in the Chandigarh city. Find out solar panel tilt angle. At which tilt angle, solar panel produces maximum ac output energy?

Solution

There is small variation in the latitude of various places in the Chandigarh city so it is recommended that take latitude of Chandigarh city.

Method 1

Find out location of Chandigarh city

Latitude: 30.73

Longitude: 76.77

Method 1

The solar panel should be installed at 30.37 tilt angle to produce maximum ac output energy therefore tilt angle is equal to latitude of the city.

Method 2

Tilt angle as per season

Summer tilt angle = Latitude of site + 15 degree

                             = 30.73 + 15

                             = 45.73

Winter tilt angle = Latitude of site – 15 degree

                           = 30.73 – 15

                           = 15.73

Yearly tilt angle calculation = (Summer angle + Winter angle) / 2

                                             = (45.73 + 15.73) /2

                                             = 30.73

Method 3

Calculate average yearly tilt angle calculation

Summer tilt angle calculation = 0.69 × (Latitude of Chandigarh) + 3.7

                                           = 0.69 × 30.73 + 3.7

                                           = 24.90

Winter tilt angle calculation = (Latitude of Chandigarh) + 10

                                        = 30.73 + 10

                                        = 40.73

Yearly tilt angle calculation = (Summer angle + Winter angle) / 2

                                             = (24.90 + 40.73) /2

                  = 32.815

Method 1, method 2 and method 3 are used to find tilt angle of solar panel installed but method 1 gives optimum result.

FAQs on tilt angle

Which is ideal tilt angle for solar panel?

Latitude of site

What is ideal orientation of solar panel?

South direction for northern hemisphere countries and north direction for south hemisphere countries

Define: Latitude

The angular distance of your panel location from the equator is known as latitude.

Whether the tilt angle is kept 90 degree?

Yes, it should be kept at 90 degree for north pole countries and south pole countries. However, it is also kept 90 degree by placing solar panel vertical to the wall.

Whether the tilt angle is kept 0 degree?

The tilt angle is kept 90 degree for countries whose location at equator. However, there is possibility that dust accumulation on solar panel with 0 degree or horizontal surface solar panel.

What should be ideal tilt angle for location of solar panel near sea area?

It should be below 12 degree in order to protect them heavy wind pressure and cyclone near sea region. 

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