In a Heat Pipe collector, the Sun’s energy that is absorbed by the double glazed evacuated tubes is transferred to a unique copper heat pipe, and then to your water by a special food grade liquid, that once heated expands and turns to gas, much like steam from a heated kettle. It then rises at extremely high temperatures to the tips of the pipes, which are inserted into a heat transfer manifold, located on your roof. It is here, that all of the energy gained from the sun is transferred to your hot water.
As the water in the manifold is heated, the gas in the tube cools and returns to a liquid to start its journey up the tube, once the sun has done its job and turned it back to heated gas again.
The strict design principles of the double walled glass evacuated tube mean that heat loss is kept to an absolute minimum, ensuring that almost all the energy gained by the tubes is transferred to your hot water. Also because there is no actual water flowing through the glass tubes, in the off chance that one of the tubes breaks, the system continues to operate, still generating hot water, even though efficiency is lost and it is recommended that the tube is replaced as soon as possible.
Flat panel solar collectors can also produce a similar heat output to evacuated tube collectors, but generally only during warm, still, sunny conditions and the sun has to be at a 90 degree angle, directly above the panel for it to work at 100% efficiency.
Where as an evacuated tube collector is round, it doesn’t need to be perpendicular to the sun to deliver 100% efficiency.
In fact, when averaged over an entire year, evacuated tube collectors can be up to 80% more efficient than flat plate panel collectors.