The Sun
Our sun is an energy generator by itself. It creates energy through nuclear fusion that takes place inside the core of the sun. The Sun is made out of interstellar medium that consist of about 73% hydrogen, 25% helium and remaining are heavy metals. Due to the high content of Hydrogen with extreme gravitational pressure towards the core of the sun, the temperature rises and there is sufficient energy for nuclear fusion reaction to occur. The nuclear fusion is the process of combination between lighter elements to form heavier element while giving off energy. In the sun, hydrogen are converting into helium while emitting energy in term of Electromagnetic Radiation Wave. This energy we often called it Sunlight Energy or Solar Radiation Energy.
The Solar Radiation Energy is composed of about 10% Ultraviolet, 40% Visible and 50% Infrared Electromagnetic wave when it reaches at the outermost atmosphere of the earth. This constant emission of entire wavelength distribution is the availability of Sunlight Power or often being called “Solar Irradiance”. Ultraviolet wave is further absorbed by the Ozone Layer while part of infrared wave energy are being absorbed by particles or molecule in the air layer. Visible light may sometimes be blocked or reflected by thick air modules or clouds. The balance of the energy that reaches the surface of earth is then can be captured and transformed into useful energy.
By estimating the Sun’s surface temperature and distance between the Sun and Earth, we can estimate the amount of Power radiates reaching the Earth. With the Sun’s surface temperature of about 5800K, we could estimate the average Solar Irradiance reaching at the outer atmosphere (before reaching earth’s atmosphere) to be approximately 1,367W/m2 with variation around ±3% as the earth orbits the Sun in an elliptical path. This value is also known as Solar Constant and the value does not change much throughout the entire year. It is the potential Solar Power that can be harvested if the Power is not lost or being absorbed by the atmosphere. The distribution of Solar constant is indicated by the area shaded in yellow and orange color on the diagram above (at extra-terrestrial level).
When the Solar Irradiance penetrates further reaching on the Sea Level during clear sunny noon, the Solar Power directly shines on surface could reduce to about 1,000 W/m2 in average due to atmospheric molecular absorption. In other words, for every square meter of Solar Panel or collector size, we can harvest 1,000W of useful Power from the Sunlight if the device has 100% energy conversion efficiency without any internal power losses during conversion. This 1,000 W/m2 value is also became the Standard Test value use in Solar PV industry to determine the capacity and performance of a solar panel. It is equivalent to the total shaded area in Orange color in the graph above.
Hi, this is a comment.
To get started with moderating, editing, and deleting comments, please visit the Comments screen in the dashboard.
Commenter avatars come from Gravatar.