Monday, September 19, 2022

Optimum Angle For Solar Panels

Consider The Expense Of Mounting

DIY Solar Panel: Best Angle for Solar Panels, Optimum Tilt Angle and Direction

If you decide to mount your solar panels for the optimal angle, its worth considering the cost of mounting. This obviously adds expense to your initial installation, and it may be too costly to bother with. Well discuss shortly the level of effectiveness you can expect to lose if your solar panel angle isnt ideal, so you can make an informed decision whether the improved angle will pay off over time.

Yes, youll be able to generate more power over the life of your solar panels, but whether that extra energy delivers a financial benefit equal to the cost of mounting is always up for debate.

What Is The Best Solar Panel Tilt For Each Season

The angle of the sun not only changes based on different latitudes, but also with the change of seasons. As shown in the illustration below, the sun is lower during the winter months and higher in summer months.

The sun is lower in the sky during winter. Image source: Lighting Research Center

This means that if you wanted to ensure that your solar panels are always positioned for maximum exposure to sunlight, you would need to adjust them for each season.

The table below shows the optimal solar panel angle for various states in the U.S. during winter, spring/fall, and summer.

Optimum solar panel angles for various U.S. cities

State

Source: Solar panel tilt

However, adjusting your solar panels four times a year is not a straightforward task. After all, most solar panels are mounted on the roofs fixed angle and cant be adjusted.

The only way to adjust solar panels easily it to utilize a ground-mount system and install axis-tracking solar panels. However, theres a big downside to this approach: while it does increase solar output, it increases your costs by much more. As a result, solar axis trackers currently arent worth the investment.

Now, are you wondering why you still only get 75.7% of optimal output after adjusting for each season? Thats because the remaining amount can only be achieved by adjusting for solar panel direction during the day.

Learn more: What is the best direction for solar panels to face?

Is It Worth Tilting Solar Panels

The amount of tilt angle recommended for your solar panel array depends on your geophysical location, but its a bit more complicated than that!

The table below shows the difference in the suns energy falling onto a flat panel surface compared to a panel mounted at a tilt angle of 50° in Denver Colorado.

In Denver, the amount of suns energy falling onto a flat solar panel is almost 50% of that irradiating a panel mounted at 50°. Thats quite a reduction.

However, in high summer, the amount of energy falling onto the flat mounted panels is more than the tilted panel. This means that the annual irradiance should be taken into account before deciding on tilt angle.

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Which Matters More: Solar Panel Orientation Or Angle

While the angle of your solar panels is important, the most important factor in your energy production is the direction your panels face. As previously explained, for the best results, solar panels should be oriented towards the south because the sun is always in the southern half of the sky in the northern hemisphere.

Its not a good idea to install your panels to face a suboptimal direction even if it means the best tilt possible. For example, in Boston, a solar array at 30 degrees south is still going to produce more electricity than an array tilted at 42 degrees and facing north.

The Best Angle For Solar Panels

Optimum Tilt Angle For Solar PV Panel

Believe it or not, the best angle for solar panels is different depending on where you live. Naturally, you always want your panels on the side of the roof that gets the most daytime sun. However, the actual angle you should aim for changes from state to state. This is because the ideal angle is always equal to the latitude angle of your homes location.

As a rough guide, the optimal angles for solar panels are listed below for Australias capital cities.

  • Sydney 33.9 degrees
  • Adelaide 34.9 degrees
  • Darwin 12.5 degrees

So, if you are in the process of building a new home, you could request that your home be constructed with a roof pitch equal to your latitude angle. This way youll always have optimal conditions for solar panels. On existing homes, however, you may need professional panel mounting to achieve the optimal angle.

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Why Does This Work

The recommended angles can seem counterintuitive. For example, consider summer at 40° latitude. At noon on the solstice, the sun is 40° – 23.5° which is 16.5° from directly overhead. To capture the most sun at that time you would tilt the panel 16.5° to point it directly at the sun. On other days of the summer it is a bit lower in the sky, so you would want to tilt the panel a bit more. Yet we say to tilt it only 12.5°. The sun is never that high. How can that be right?

The answer is that we are considering the whole day, not just noon. In the morning and evening, the sun moves lower in the sky and also further north . It is necessary to tilt less to the south to collect that sunlight.

Atmospheric Scattering And Solar Power

The Earthâs atmosphere normally causes light scattering, but the air isnt always clear: pollution in the form of particulates and nitrogen oxides can have a significant effect. This type of pollution can be caused by such things as fossil fuel power plants, forest fires, dust storms, and vehicle exhaust. For this reason, an accurate solar energy calculator needs to take into account both normal atmospheric scattering and the effect of pollution.

Pollution of this type can be quite predictable. In the United States, meterological stations measure common pollutants such as particulates, ozone, and nitrogen oxides, so this data is commonly available.

Because of that, itâs possible to include this data in a model that accurately takes into account both direct sunlight and atmospheric scattering, and calculate the ideal solar tilt angle for your location.

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Solar Tracker Cost Analysis Calculation

Example: 5 kW solar panel system

Location: South Bend, Indiana

  • Cost of installation $15000 = $10000
  • Energy produced 7110 kWh = $748.68/annum
  • Payback time = $10000/$748 = 13.5 years

Dual Axis Sun-tracker:

  • Total Installation cost = $20000 = $14000
  • Energy produced = 9243 kWh = $973/annum
  • Payback time = $14000/$973 = 14.4 years

In the example above the payback time is a little longer, but after the payback time the electricity is free.

The above example doesnt account for maintenance costs of the of the solar-tracker. Any system with working parts will have maintenance costs associated with its operation.

Solar Losses If Your Panels Are Angled Wrong

Fixed mount Solar Panel Optimum Tilt Angle Analysis

If you choose to stick with a flat installation using the pitch of your roof, its important to know what sort of efficiency decrease you may experience. The general consensus is if your solar panel angle is 10-15 degrees on either side of the optimal range, youll lose roughly 1-1.5% efficiency. So, generally, if your roof is pitched to any degree, youre not likely to lose a whole lot of efficiency.

But what if your rooftop is flat? You are still able install solar panels on a flat roof, however, you can expect energy production to decrease a bit more significantly. For example, if youre in Sydney with an optimal angle of 34 degrees, and your roof is flat, you could lose up to 13% efficiency. In Darwin, however, a flat roof barely loses any production. The further south you go, the more you lose by installing on a flat roof.

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What Angle For Solar Panels Should Be Chosen To Maximize The Production All Year Long

In solar thermal energy : The aim is to produce more heat in the winter and less heat in the summer. Example: In Marseille, for conventional thermal energy, 4m² of panels are necessary for a typical homes hot water needs and the best inclination of the panels is between 50° and 55°. This inclination does not correspond to maximum sunshine, but because there is a surplus of production in the summer, it is better to optimize the angle for the winter.

For photovoltaic panels where the electricity is re-injected into the grid for re-sale , the optimum orientation is south with an angle of a 37°, which maximizes total electricity production.

PV -T: With the DualSun PV- T panels, which produce both electricity and hot water, the optimal angle is the same as for PV panels.

Example: For a DualSun installation in Marseille, we recommend a 4-panel design for a family of 4. The best angle for that is maximum sunshine .

Which Is More Important Angle Or Orientation

Because of all the nuances and various factors involved with determining the proper angle of your solar panels, you might think that it is the most important factor come installation. However, the opposite is true. When it comes to solar panels, determining the correct orientation is the most important variable.

Improper orientation will mean that your panels wont get enough exposure time to the sun, reducing your electricity output drastically. The wrong angle on the correct orientation will produce more energy than the correct angle on the wrong orientation.

Solar panels are a great way to improve the efficiency of your home and reduce your carbon footprint. There are a lot of factors to consider when deciding to go solar other than the potential cost savings. The company you choose will have the knowledge to install your solar panels appropriately, however, knowing a few key principals about solar panel installation is always a good starting point.

Proper solar panel orientation and angle is the ideal place to start since these two factors have the greatest effect on efficiency. Dissect the information this article lays out, and work the numbers as they pertain to the location of your home. This will enable you to compare information with your solar panel installer in order to make sure your panels are set up to run as efficiently as possible.

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Adjusting The Tilt Four Times A Year

If you are going to adjust the tilt of your solar panels four times a year, and you want to get the most energy over the whole year, then this section is for you. This would be your situation if you are connected to the grid and can use or sell all the power you produce.

The following table gives the best dates on which to adjust:

Northern hemisphere
Adjust to summer angle on
Adjust to autumn angle on
Adjust to winter angle on
Adjust to spring angle on

If your latitude is between 25° and 50°, then the best tilt angles are:

  • For summer, take the latitude, multiply by 0.92, and subtract 24.3 degrees.
  • For spring and autumn, take the latitude, multiply by 0.98, and subtract 2.3 degrees.
  • For winter, take the latitude, multiply by 0.89, and add 24 degrees.

If your latitude is outside this range, see Other Situations below.

If you want to adjust the tilt of your panels four times a year, you canuse these figures to keep capturing the most energy year-round. This table gives some examples:

Latitude
46.7 68.5

In winter, a panel fixed at the winter angle will be relatively efficient, capturing 81 to 88 percent of the energy compared to optimum tracking. In the spring, summer, and autumn, the efficiency is lower , because in these seasons the sun travels a larger area of the sky, and a fixed panel cantcapture as much of it. These are the seasons in which tracking systems givethe most benefit.

The Best Angle For Solar Panel Installation

How to find the Best solar panel angle or tilt angle

When installing home solar panels, its important to install them at the best possible angle to maximize their sun exposure. Not only can this affect energy production, but it also directly impacts how much money you may save on your electricity bill. If you want to learn how to get the most out of your investment, keep reading to learn:

  • The importance of solar panel orientation
  • The optimum angle for solar panels
  • The factors that influence the optimum tilt angle

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It All Starts With Aspect

No matter what angle for solar panels you select, if you place them on the wrong aspect it wont matter. You may have noticed around your home that certain areas of your property get more sunlight than others.

This can fluctuate with the time of day and seasonal variations in sunlight. That said, if you live in the northern hemisphere you may have noticed that the south-facing rooms in your home get more light than the north.

This is because the sun rises in the east and sets in the west. Throughout the entire duration of its journey, it takes a slightly southern arc through the sky. This is only true when looked at from a fixed point in the northern hemisphere.

The reverse is true in the southern hemisphere, where northern aspects get an abundance of sunlight each day. The equator is the dividing line. A lot of this phenomenon has to do with the Earths tilt, rotation, and orbit.

Solar Radiation Data On Horizontal Surfaces

Interestingly, the majority of solar radiation data recorded in Australia is based on a horizontal surface, or if you like, a flat roof. For the purposes of calculating solar power output at a specific location, we start by using solar exposure figures recorded by the Bureau of Meteorology at your location, which are recorded on horizontal surfaces. We then extrapolate the data supplied by the Clean Energy Council on generation loss of panels due to their orientation and tilt then we apply the necessary panel efficiency deratings. All of this data is utilised to provide an accurate measurement of solar power based on the location, roof tilt and orientation that you input into the calculator.

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Solar Panel Direction And Angle Solar Tracking

Solar panels can be adjusted in two directions tilting up and down or side to side.

The ideal situation would be for the solar panel surface to be always at 90° to the suns rays. This can be achieved by mounting the panels on a mechanical apparatus called a Solar Tracking System.

This kind of automatic setup senses the suns location and tracks it across the sky, thus optimizing the power output.

The Best Angle For Solar Panels By Type Of Roof

At What Angle Should Rooftop Solar Panels Be Installed?

If your roof is flat, you still need to have a small inclination of about 5-10° to prevent water from pooling at the panels. Water should find its way from the surface of the panels because you dont want it to penetrate into the seals and damage the solar cells.

Most panel brands state the 10° warranty condition, and if have your flat, youll void your chance to receive compensation.

4.85

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Why Is The Angle Of Solar Panels Important

The angle at which you install your solar panels is important from an efficiency point of view. The more sun you capture at the ideal angle, the more energy your solar system produces. This means more energy to power your home and potentially more energy to export for feed-in tariff credits.

Aside from the angle, there are a few general rules for maximising solar panel output. Firstly, a roof facing the north sun will be most effective. Ideally, you also want your solar panels positioned perpendicular to the sun for maximum benefit.

What Is The Best Angle For A Pitched Roof

Pitched roofs with angles between 30 and 40 degrees will work well in most situations. In an ideal world, all roofs would be already prepared at the perfect angle, but of course, this is not the case. Pitched roofs that do not allow this angle can still have solar panels fitted, and energy will still be generated.

  • A 30-degree angle makes the most of sunlight in the morning and evenings
  • Roofs that fall outside of this range may be fitted with brackets to tilt the panels more effectively
  • Solar panels that sit at a lower angle will not be able to self-clean as effectively causing a build-up of dirt
  • The angle of your roof has less impact than the direction it faces

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Best Solar Panel Angle By Zip Code

Here is a table with the best solar panel angle for over 800 of the most populated zip codes in the US. You can sort it or search it to quickly find yours.

Note: All angles are from horizontal.

City
13.1° 43.1°

Don’t see your zip code on this list? Use the solar panel angle by zip code calculator at the top of this page to calculate the best tilt angle for your location.

What If The Roof Faces East And West

Optimum Solar Tilts for Multiple Tilt PV Mounting System

Many people have their roofs facing east and west instead of North and South. Orienting your solar panels to the east attracts lots of morning sunshine and produces a lot of electricity.

In the late afternoon when the sun is hot, your panels will still be producing more as long as they face west. Such an orientation works pretty well when youre looking to produce solar power for your personal use.

However, when you want maximum power from your solar systems, you will want to position them at the most ideal tilt angle for your city. This way, they will produce more electricity in the morning and in the afternoon.

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