PR Solar Tubes are the latest generation of evacuated tube heat collectors, as with all evacuated tubes light only is required not just direct sunlight.
The round shape of the tube collects diffused and direct radiation, as light is collected by the black coating inside the tube this energy is converted to heat which cannot escape because of the vacuum between the two layers of glass (like a thermos flask). This heats the distilled water in the copper insert tube and this in turn rises to the top to heat the manifold through heat exchange. Because the distilled water is in a vacuum it boils at a temperature much lower than 100 degrees C.
Manifold and Roof Mounting Kit
Manifold and Roof Mounting Kit are constructed of aluminium (black anodised) and therefore light-weight for roof surface mounting.
The control panel is very user friendly and is multi-functional in its settings ability. This allows personal settings of max temperature in the cylinder and frost-protection settings. A one press button displays all the temperature readings on your system (cylinder top & bottom/roof).
This is a high-quality station which has a “Wilo” pump twin non-return valves, an in-line filling point for system pressuring. It also has an in-line air-exhaust valve to bleed any air from the system.
It has two temperature gauges for the flow and return line and a system pressure gauge and pressure relief valve/safety blow off to prevent over-heating.
This is standardly placed to take and return Glycol as the system heats and cools.
Cylinders can be supplied for every requirement – two coil, three coil or four coil where there are additional heat sources to the solar water heating coil.
Systems can be pressurised (closed) or gravity fed unpressurised (open) depending on requirements and local water-pressure.
Conventional copper cylinders are inadequate because of poor insulation and the heat-conductivity of copper.
The new stainless steel cylinders have 50mm high-density insulation providing an overnight heat loss of less than 5% compared to the vast heat loss of a conventional cylinder. They are manufactured of 316L stainless steel allowing them to boast a 20 year warranty. They are suitable for hard-water areas and are available in many capacities and sizes as each household require.
East west controller are an option where the house-facing is unsatisfactory but the expense can be avoided by using more tubes if possible because of the high efficiency of the new-generation tubes.
Overall the evacuated-tube collecting system is the best option at these latitudes and the system is easily placed securely on the tiles or slates, requiring no large hole in the roof. The complete system carries a 20 year guarantee.