How it works.

Our solar panels consist of evacuated tube collectors (Flat plate panels can also be installed) attached to a southerly facing roof. Water (and a special antifreeze mixture) is the pumped through the panel where upon it gets heated. The heat is then transferred by a high efficiency coil in a specialist solar cylinder assisting your boiler heating the water.

Evacuated tube panel

These top of the range solar panel heat collectors are suitable for heating domestic hot water and swimming pools etc. One unit is generally adequate for an average household (3-4people), and it is modular, so more can be added if required. A single panel is sufficient for a 200litre cylinder, but we can fit 2 or more for high water usage or for heating swimming pools. And with an overall efficiency of almost 80%, they are much more efficient than electric photovoltaic solar panels.

The Panel

This high tech unit concentrates the sun's energy at the tip of the copper 'heat tube' - like a solid state magnifying glass. The vacuum tube solar panel has been around for over 10 years, and has proved to be reliable and dependable.

The vacuum tubes consist of a double wall glass tube (made from strong borosilicate glass i.e. 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 optimized 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

The Evacuated Tubes

The heat transferred to the tip of the heat pipe is in turn transferred to a copper manifold in which water circulates to heat the domestic hot water tank. If a tube is placed in direct sunlight on a summer day, the tip temperature can reach 250°C so the system easily heats domestic hot water cylinders to 60°C even in cooler weather! The manifold is heavily insulated with a 2" thickness of pre-formed rockwool to keep the heat in. Unlike flat plates, these headers are so well insulated that they should not require antifreeze in normal operation - the temperature of the header is unlikely to fall below 10°C even in very cold weather. Antifreeze is however used because it has the added effect of increasing the boiling point of the fluid.

The Collector Manifolds.