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Increase solar panel output by 7-8% with an Optimal angle

Have you ever wonder how to increase the energy production of your existing solar panels to meet your increase in power demand. Motorized Sun tracking systems are highly expensive and required a huge place (almost double than the fixed-tilt structure) to install. Also, the maintenance cost of the sun tracking system is higher than that of a fixed structure.

The optimal angle for a solar panel is defined as the tilting angle at which PV panels produce more power (7 to 8%) for different seasons as compared to the fixed solar structure. However seasonal structures are used for fixing PV panels to get the optimal angle for different seasons. Seasonal structures are a little higher in price than that of fixed structure but are very cheaper than the sun tracking system.

The thump rule of determining optimal angle for PV panel is to add 15 degrees to the latitude of your region for winter season and summer season you need to minus 15 degrees for the latitude to get an increase (7 to 8%) the power production of the PV panel and this can be practically implemented in any location throughout the world.

To find the latitude of your place, all need to do is go to Google map and right-click on your place. After right-click, you will find a window on Google map (as shown below) and the first two digits will represent the latitude of your place.

The above picture shows the latitude of the network city (that is 40 degree)

There several brief pieces of literature available on the internet regarding the studies executed by different authors to determine the optimal tilt angle of the PV. Some of them are listed here

Optimal Tilt Angle Computation

From different studies on the optimal angle for PV panel, I used the real-time data for one of the studies held on the rooftop of UIET, Panjab University (Chandigarh, India). In this experiment, 5 numbers of solar PV plants of rated capacity 1 kW each have been installed at different tilt angles (10,20,25,30 & 40) for the year 2018. [Click here to download the complete study paper]

Also for this experiment, Zytech Model ZT 320P solar panels are used with grid-tie micro-inverters of SOLAX.

Here is the table showing the real-time data of power generation (in kWh) by 1kW of a solar power plant from a different angle.

Now from table#1, I extract the monthly optimal angle and listed it down below.

Further, the effectiveness of the optimal angles can be analyzed by comparing the energy response obtained at recommended fixed angles. Since the latitude of Chandigarh, India is 30° let’s compare the power generation from optimal angles with the power generation at fixed 30° and 40° as represented in Table#3.

It can be seen in Table#3 that the optimal energy obtained is 5221.5 kWh, whereas the energy generated at a fixed angle of 40° is 4886 kWh which is approximately 336 kWh less than optimal angle energy, similarly, for 30°, the energy obtained is 4822 kWh having a difference of 400 kWh Therefore, if the PV panel is adjusted monthly at optimal tilt angle rather than fixed at 40° and 30° tilt angles, energy generation can be increased from 7% to 8% from the fixed angle energy.

Seasonal Structure for Solar Panels

Seasonal structure for solar panels makes it very convenient to change the tiling angle of solar panels.

The below picture shows an example of a seasonal structure for solar panels. It can change the tiling angle of solar panel from 25 degrees to 40 degrees.

The space requirement for Installing a seasonal structure for a plant size of 1 to 2 kW is the same as on a fixed structure.

However, installing seasonal structures for solar plant size above 5 kW required much more space than a fixed type structure. Also, a seasonal structure is more suitable for a flat rooftop than a sloping rooftop.

If you need tailored made detailed drawing of seasonal structure for your solar project you can write to me at


Brief literature review regarding the studies executed by different authors to determine the optimal tilt angle of the PV.

Author Name: Jacobson et al. (2018)

Methodology Used: PV watts calculator used to find solar panel output by varying tilt angle. Equation of optimal tilt angle as a function of latitude is formed

Location: Major countries in the world

Author Name: Ozbay et al. (2017)[

Methodology Used: Manually setting of a panel at different angles and input data to a controller to calculate power and current output to find optimal tilt angle.

Location: BIlicek city, Turkey

Author Name: Kaddoura et al. (2016)

Methodology Used: MATLAB code has been made in which solar radiation data from NASA has been input which optimizes tilt angle according to solar radiation.

Location: Different cities in Saudi Arabia

Author Name: Morad et al. (2018)[10]

Methodology Used: Bernard-Menguy-Schwartz model is used to made tilt angle model and programmed using the EES (engineering equation solver).

Location: Different cities in Iraq

Author Name: Jamil et al. (2016)[7]

Methodology Used: Liu and Jordan model used for total radiation estimation on inclined flat surface.

Location: Aligarh and New Delhi

Author Name: Nfaoui et al. (2018)[16

Methodology Used: MATLAB code is used to estimate the totality of the solar radiation on any inclined surface, from which optimal angle under which the maximum energy could be absorbed by the solar cells has been determined.

Location: Settat city in Morocco

Author Name: Salari et al. (2017)[

Methodology Used: MATLAB code has been developed to calculate the monthly average daily total solar radiation on a surface. The developed program calculates the optimum slope angles which correspond to the maximum amount of received irradiation.

Location: Yazd, Iran

Author Name: Salavati Pour et al. (2011)[

Methodology Used: Three different mathematical models are used namely Liu, Klein, and Hay to determine the monthly optimal angle

Location: Isfahan, Iran

Author Name: Khatib et al. (2015)

Methodology Used: Liu and Jordan model for solar energy incident on a tilt surface have been used for finding the optimal tilt angle.

Location: Different cities in Malaysia

Author Name: Benghanem et al. (2011)

Methodology Used: Different isotropic and anisotropic mathematical models used. MATLAB, NREL data (1998–2002) for Saudi

Location: Madinah, Saudi Arabia

Author Name: Asad Ullah et al. (2019)[

Methodology Used: MATLAB code was developed to calculate the total solar radiation incident on a solar panel using Liu-Jordan and Hay’s model.

Location: Lahore, Pakistan

Author Name: Dutta et al. (2016)

Methodology Used: Liu and Jordan model has been used to simulate solar radiation model.

Location: Kolkata, India

Author Name: Fung et al. (2005)

Methodology Used: Optimum angle has been calculated by using Hottel and Woertz and Reindl model to formulate solar radiation model

Location: Hong Kong

Author Name: Shu et al. (2006)

Methodology Used: Small PV modules at different tilt angles have been installed and power output of modules has been determined and validated through solar radiation model. Second-order polynomial equation has been deduced from experimental data to determine the optimal angle.

Location: Kitakyushu, Japan

Author Name: W.G. Le Roux (2016)

Methodology Used: For each of the locations, the annual solar insolation on a fixed tilted surface was obtained for all the possible combinations of collector tilt angles. Validation is done through real time data.

Location: Different cities in South Africa

Author Name: Yakup et al. (2001)[

Methodology Used: A mathematical model was used for estimating the total (global) solar radiation on a tilted surface. Comparison between mathematical model and simulation has been done.

Location: Brunei, Darussalam

Author Name: Tang et al. (2004)[

Methodology Used: Collares-Pereira and Rabl model has been used for the estimation of diffuse-radiation, Klein and Hamilton model used for Rb and Rd

Location: Different cities in China

Author Name: Tlijani et al. (2017)[

Methodology Used: PV panel rotated at five different directions and angles.

Location: Tunisia

Author Name: Sinha et al. (2016)[

Methodology Used: HOMER software calculate global radiation on pv panel using Hay, Davies, Klucher, and Reindl model which is used to calculate the optimal tilt angle.

Location: Different sites of Himachal Pradesh, India

Author Name: Bailek et al. (2018)[

Methodology Used: Perez9 model used in solar radiation mathematical model to determine optimal tilt angle.

Location: Adrar city, Algeria

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