Solar energy is classified into two types based on the way in which solar energy is utilized
1. Active Solar Energy
2. Passive Solar Energy
The passive solar energy is used directly from the Sun for various applications without using any intermediate devices or converters. Example: Solar heating and cooling
Active solar energy reduces a building’s fossil fuel energy requirements for loads operation. The solar energy from the sun is converted into electricity by using an intermediate circuit (Photo voltaic cells).
Solar energy can be converted to electricity in two ways:
- Photovoltaic (PV devices) or “solar cells” change sunlight directly into electricity. They are used to powering watches, calculators, and lighted road signs. Sunlight is composed of photons, or particles of solar energy. These photons contain various amounts of energy corresponding to the different wavelengths of the solar spectrum. When photons strike a photovoltaic cell, they may be reflected, pass right through, or be absorbed. Only the absorbed photons provide energy to generate electricity.
- Solar Power Plants – indirectly generate electricity when the heat from solar thermal collectors is used to heat a fluid which produces steam that is used to power generator.