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How to calculate Peak Sun-Hours of your area?

Release:2017/08/23 Company News

As energy costs continue to rise, more and more people are looking to solar power as a more efficient option for both their homes and businesses. On top of the economic benefits of solar power, solar energy produces no pollution and has no negative environmental effects, making it an attractive option for those concerned about the environmental effects of traditional energy production as well.


If you are trying to determine whether or not solar power is the best option for your home or business, it’s important to understand how much sun solar panels need in order to operate effectively, what peak sun-hours are, and what you can do to get the most out of the solar power available to you.


How Much Sun Do Solar Panels Need?

Solar power is created through the harnessing of energy from the sun. Solar panels — which are typically made of crystalline silicon and use a system of lenses or mirrors to maximize the light that reaches them — create an electric current when exposed to sunlight, which is then used to produce electricity.


Solar panels need direct sunlight in order to produce the maximum solar output. Even in cloudy weather, however, solar panels can absorb solar energy to produce power, though it will be at a significantly reduced rate compared to sunny days — usually between 25 and 40%.


To maximize the amount of sunlight your panels receive, they should face the sun and be installed in an area where they will not be shaded by trees or other nearby buildings during the majority of daylight hours. While a solar professional can help you determine the best placement for your panels, you can plot a sun chart or buy or rent a solar pathfinder to determine how much sun your solar panels are likely to receive on a typical day.


What Are Peak Sun-Hours?

While the amount of sunlight your panels receive is important, a more accurate representation of the amount of energy your panels can produce is peak sun-hours. It is important, first of all, to note that “peak sun-hours” are not the same as “hours of daylight.” Peak sun-hours refers specifically to how much solar energy is available in an area during a typical day. A peak sun-hour, specifically, is an hour during which the intensity of sunlight is 1,000 watts per square meter.


The amount of solar radiation, or insolation, delivered by the sun varies throughout the day, based on the sun’s position in the sky, clouds, and other atmospheric conditions.


Time of Day:  Peak solar radiation occurs at solar noon, when the sun is highest in the sky. The low angle of the sun at sunrise and sunset means that the atmosphere filters the sunlight more and results in less energy being delivered to the earth’s surface.

Season: Sun-hours increase during the summer due to the sun’s higher position in the sky.

Geography: Solar energy increases near the equator, as it is closer to the sun.

While your panels may receive an average 7 hours of daylight per day, the average peak sun-hours may actually be closer to 3 or 4.


How to Calculate Your Peak Sun-Hours


The easiest way is visit NASA’s website

Then input Latitude and Longitude data of your location (Figure 1), click “Submit” button to get result.


Figure 1


It will show Daily solar radiation – horizontal kWh/m2/d by month.

For Example (Figure 2): Daily solar radiation of January in Casablanca,Morocco is 3.04kWh/m2/d, then we can get equivalent Peak Sun Hours by dividing Daily solar radiation by 1000W/m², which means radiation lasts 3.04 hours at 1000W/m²density, then Peak Sun Hour is 3.04 hours for January.


 Figure 2