A few years ago solar panels were an uncommon sight in Britain. Today, they are appearing all over the country as increasing numbers of homeowners discover that improved technology and government incentives are at last making solar energy a practical alternative to carbon-based fuels. In the future, it could well be that a house without solar panels will seem strange!

The first thing to understand about domestic solar panels is that there are two very different types: solar thermal panels and solar photovoltaic panels.

Solar thermal panels
These solar panels are designed to capture the sun’s energy and use it for powering a home’s hot water system. They contain a heat transfer fluid – usually a non-toxic antifreeze – and when heated by the sun this hot fluid flows from the solar panel to a coiled pipe inside a hot water cylinder. As the water in the cylinder heats up, the heat transfer fluid cools and is pumped back to the solar panel to be heated again.

Solar thermal panels are normally added to an existing hot water system with an automatic switching device that switches on your conventional hot water boiler when the solar panels alone are unable to maintain the required water temperature. This gives you the convenience of hot water whenever you need it but reduced fuel bills as free solar power is being used during daylight hours.

Solar photovoltaic panels
Solar photovoltaic panels (often abbreviated to solar PV panels) generate electricity from the sun’s radiation. They contain solar cells, made mostly from silicon, which convert light energy into direct current electricity. This DC electricity must then be fed to an inverter that changes it into alternating current (AC) so it can be used in a domestic electrical system.

Solar PV panels can only generate electricity when light is falling on them, and they cannot store electricity for use at other times. The best solution to this problem for households in England, Scotland and Wales is to join a Feed-in Tariff Scheme. Your home remains connected to the mains electricity supply, and you can draw on this power whenever you need it, but when your PV panels are working, your electrical appliances run on free solar power. The added advantage of this arrangement is that your energy supplier will pay you a fixed tariff for generating some of your own electricity. In addition, if your PV panels generate more electricity during the day than you use, the excess is fed back to the grid and your energy supplier will pay for the amount of electricity you export to them.

source: aboutmyarea