Solar Energy Today - Not Just For Heating
And solar energy can be and frequently is used to provide heating.
Often solar power is used to provide heat to a house or for hot water by installing solar collectors which trap the heat and circulate it with water.
This is also used to heat swimming pools and so extend the period of the year that they can be used.
But there are a number of less obvious ways that the power of the sun is used nowadays, and you may have seen some of them.
A range of uses come from photovoltaic technology, that is, generating electricity from the sun to light a house.
You can buy outside path lights that don't need connection to an electricity supply, and these have photovoltaic cells built into the top with a battery inside.
When it gets dark, the lights come on, using the solar energy stored in the battery, to provide lighting in the garden during the evening.
Exactly the same idea is used for road signs in remote areas - you can identify these by the solar cells which are attached.
A further use, which many people own, is a calculator with built-in solar cells, usually supplementing the battery power.
A major focus of research and design in solar energy today is the development of solar cells that can supplement or replace the power to your house.
These are substantial in size, perhaps a couple of hundred square feet in area, often fixed to the roof, and they will provide enough electrical energy for an efficiently run house to function normally.
This type of use received a big boost in the USA in 2005, when a law was passed requiring electricity suppliers to implement net metering, where excess electricity generated on site and fed into the network offsets the cost of electricity delivered.
Effectively, this can replace the previous requirement for batteries for energy storage, as the power grid becomes the storage, and it significantly reduces the cost and inconvenience.
This law is still being worked on in some states, while others have embraced it more enthusiastically, and it's set to change the way we look at solar energy in the future.
Finally, while you may be fairly familiar with the uses of solar energy today described above, one you may not have heard of is using solar energy for cooling or air conditioning.
Without going too deeply into the technicalities, this is mainly used for commercial purposes, and it functions in a similar way to a gas refrigerator, such as you can find in an RV.
The cycle is called absorption cooling, and it uses the sun's heat to produce the cooling effect.
Solar energy today is a very flexible energy source!