Discover Your Solar Energy Potential |
There are two ways in which solar energy 'works' - that is, works for us.
1. We can trap the heat from the sun and use it.
(Solar Thermal or Solar Hot Water)
2. We can take the energy from the sun and turn it into electricity.
(otherwise known as photovoltaics)
The sun radiates an incredible amount of energy every day. Less than an hour of earth's sunlight can supply all humanity's needs for a year.
Solar Energy - Photovoltaics and Electricity
The way photovoltaic panels work is by using the photons, or packages of sun energy to set off a molecular reaction. Silicon is doped with boron to create molecules that shed an electron when sun strikes it.
This 'photovoltaic effect' was actually discovered in 1839. When the electrons are free, they form a flow of electrons, otherwise known as electricity.
Recently, other substances than silicon have been used to create the photovoltaic effect. This is a fast growing area of science.
However, when you put solar electric panels on your roof, you are only using a small amount of the solar power available.
Typically, photovoltaic, or solar electric panels are 10-20% efficient. This means about 10-20% of the energy that strikes the panels actually gets converted into electricity for your use.
This
efficiency is gradually improving as different companies research and
develop their solar technology.
Solar Hot Water - the Sun's Heat
Using the sun's heat is the other way to harness solar energy. Solar hot water involves putting panels made up of small tubes in the sunlight. These tubes are filled with a liquid.
As the sun heats them, they either move naturally with the change in temperature (passive systems) or the liquid is circulated by a pump (active systems.)
Closed loop solar hot water systems circulate the same fluid always. This fluid then transfers it's heat to your hot water.
Open loop systems circulate the actual water and heat it directly. Solar Thermal uses the sun's heat differently. Using mirrors, sunlight is concentrated onto a pipe filled with liquid.
As this liquid heats up, it moves a motor. This is motor is often a stirling engine. Solar thermal is a fast growing solar technology and some large power plants have been built in the desert using these principles.
Related Links:
Solar Battery Chargers - Energy on the Move
Solar Cars - Race of the Future