2. The principle of solar energy Solar energy refers primarily to the use of solar radiation for practical ends. However, all renewable energies, except geothermal and tidal, derive their energy from the sun.

3. The principle of solar energy Solar technologies are broadly characterized as either passive or active depending on the way they capture, convert and distribute sunlight. Active solar techniques use photovoltaic panels( 太阳能光伏板 ), pumps, and fans to convert sunlight into useful outputs. Passive solar techniques include selecting materials with favorable thermal properties, designing spaces that naturally circulate air, and referencing the position of a building to the Sun.

4. The principle of solar energy Active solar technologies increase the supply of energy and are considered supply side technologies, while passive solar technologies reduce the need for alternate resources and are generally considered demand side technologies.

5. The Advantages of Solar Energy Be friendly to environment --Clean, renewable and sustainable --No air pollution Saves your money --The energy from sun is FREE --Not require fuel Independent --Operate entirely independent

6. Application of solar technology Solar vehicles Some vehicles use solar panels for auxiliary power, such as for air conditioning, to keep the interior cool, thus reducing fuel consumption.

7. Application of solar technology Water heating Solar hot water systems use sunlight to heat water. In low geographical latitudes from 60 to 70% of the domestic hot water use with temperatures up to 60 °C can be provided by solar heating systems.

8. Application of solar technology Solar chemical These processes use solar energy to drive chemical reactions. These processes offset energy that would otherwise come from a fossil fuel source and can also convert solar energy into storable and transportable fuels. Solar power Solar power is the conversion of sunlight into electricity.

9. The disadvantage of solar energy The disadvantage of solar energy is that it is not stable; solar energy can be affected by day and night changes largely. So we need to have a storage installation to keep the energy. But it is difficult to build such a device and the price is high. Second, because the collectors of solar energy occupy large area, so the collector is quite big. So we feel that it is very shiny when we pass the collectors. It is bad for our eyes, of course.

10. Influence of solar energy Usage of sun energy represents a milestone of utilizing renewable energy. Widespread usage of solar power popularizes this technology. It has many advantages compared with other sources. It stimulates solar industry. It brightens the future of sustainable resources