2.0 Solar Energy Basics

Solar Energy

The energy derived from the sun, which is harnessed using various technologies.

Angle of Incidence

The angle between the incident ray of solar radiation and the normal to the surface where it strikes.

Extraterrestrial Radiation (Iext)

Solar radiation incident on the outer atmosphere of the earth.

Solar Constant (Isc)

The average energy received from the sun per unit time per unit area at the Earth's mean distance from the sun, approximately 1367 W/m².

Declination (δ)

The angular displacement of the sun from the plane of the Earth's equator.

Zenith Angle (z)

The angle between the sun's rays and the vertical (normal) to the horizontal plane.

Surface Azimuth Angle (s)

The angle on a horizontal plane between due south and the projection of the sun's rays.

Albedo

The measure of how much light that hits a surface is reflected without being absorbed.

Hour Angle (ω)

The angle through which the Earth has rotated relative to the sun, measured in degrees.

Solar Azimuth Angle (s)

The angle measured clockwise from due south to the projection of the sun's rays on the horizontal plane.

Terrestrial Radiation

Solar radiation that reaches the Earth's surface after passing through the atmosphere.

Solar Insolation

The amount of solar radiation energy received on a given surface area over a specific time.

Tilt Angle (Slope)

The angle between the inclined surface and the horizontal plane.

Kinetic Energy of Wind and Waves

The energy stored in the movement of wind and waves, which is less than 0.5% of total intercepted solar energy.

Eccentricity of Earth's Orbit

The measure of how much the Earth's orbit deviates from a perfect circle, affecting solar radiation.

Renewable Energy Sources

Energy sources that are replenished naturally and can be used continuously, such as solar energy.

Hydrogen-to-Helium Thermonuclear Reaction

The process by which the sun produces energy through the fusion of hydrogen atoms into helium.

Latitude

The angular distance of a point on the Earth's surface, measured in degrees north or south of the equator.

Day Length

The duration of time between sunrise and sunset.

Solar Time

Time based on the position of the sun, as opposed to standard time established by time zones.

Solar Irradiation

The power of solar radiation received per unit area.