Solar energy is created by light and heat which is emitted by the sun, in the form of electromagnetic radiation.
Available Solar Resource
The technical feasibility and economical viability of using solar energy depends on the amount of available sunlight (solar radiation) in the area where you intend to place solar heaters or solar panels.
The amount of sunlight available is one factor to take into account when considering using solar energy.
Geographic location
Season
Local weather
When the sun’s rays are vertical (directly overhead), the Earth’s surface gets a maximum of solar energy. The more scattered and diffuse the sun rays are, the less concentrated the solar energy is. The Earth travels around the sun, in an elliptical orbit. When one part of the Earth is closer to the sun, it receives more concentrated solar energy. Diffuse and Direct Sunlight
As sunlight passes through Earth’s atmosphere, some of it is absorbed, scattered, and reflected.
Sunlight affected in this way is referred to as diffuse solar radiation or diffuse sunlight.
Sunlight that reaches the Earth’s surface without being diffused is called direct beam solar radiation or direct sunlight.
The sum total of all diffuse and direct solar radiation in a given location is called global solar radiation. Measuring Sunlight and Solar Energy
Scientists measure the amount of sunlight available in specific locations during the different times of year.
Measurements of solar energy are normally expressed as “total radiation on a horizontal surface”, or as “total amount of radiation on a surface tracking the sun”.
Solar Energy Measurements
Radiation data (the amount of solar energy available at a given location) for solar electric (photovoltaic) systems is often represented as kilowatt-hours per square meter (kWh/m2). Direct estimates of solar energy may be expressed as “watts per square meter” (W/m2).
Tags: Basic, Energy, Principles, Solar