Evacuated Tube Solar Panels:

The vacuum tube solar panel has been around for over 10years, and has proved to be reliable and dependable. The vacuum tubes consist of a double wall glass tube (made from strong borosilicate glass ie pyrex) with a space in the centre which contains the heat pipe. The sun's radiation is absorbed by the selective coating on the inner glass surface, but prevented from re-radiating by the silvered innermost lining. This is in effect like a one-way mirror which has been optimised for infra-red radiation. In fact it is very efficient, of the sun light's energy hitting the tube's surface, 93% is absorbed, whereas only 7% is lost through reflection and re-emission. The presence of the vacuum wall prevents any losses by conduction or convection - just like a thermos flask. Because of this, the system will work even in very low temperatures, unlike traditional flat plate collectors. This is why this system can be used to heat up water at the South Pole Antarctic Science Base - where ambient air temperatures can drop below -40°C.
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Water Turbines:

If you are lucky enough to have a water course across your property, such as a stream, river, or if you are lucky enough to own an old water mill, water turbines are an ideal solution for providing reliable long-term renewable energy. You can easily calculate the available power at your site using the following equation: