Solar Collectors - Choose Your Solar Collector

How Do the Tubes Work?
As the sun shines down to the collector, solar energy is absorbed by the evacuated tubes. Inside each of these glass tubes is a sealed copper pipe that contains a non-toxic liquid. Once this liquid boils, the vapor then rises to the top. The heat coming from the copper pipe is transferred to passing water. Neither the liquid nor its vapor ever comes in contact with the water. When the liquid cools it returns to the bottom to restart the process over again.

What’s Inside the Tubes?
Each tube of the solar collector is made up of vacuum insulated borosilicate glass that absorbs the sun’s rays. It’s a double walled design and contains a special solar filament/absorption layer, aluminum heat transferring fins and a copper heat pipe condenser. They are sealed tight creating a smooth, nearly seamless casing which works to create a thermos effect that prevents heat from escaping.

Essentially, the clear glass allows light in, which then becomes absorbed by the solar filament. Insulation prevents the heat/energy (just recently captured) from being released. The solar tube absorbs at a rate of 93% but it has a heat loss of less than 6%. Borosilicate glass was selected not only due to its strength but also the ability to withstand warping (in either high or low temperatures).

Tubes vs. Flat Panels
We use the solar tubes because they absorb light more effectively than flat panels. Why are the tubes more effective? Mainly it’s because of the raised and rounded shape of the tubes. They are able to grab the sun’s rays at different angles where as a flat panel can only absorb solar energy when it is perpendicular the sun. Since the earth is turning on its axis the suns light gradually travels across the sky throughout the day. Take a look at the diagram to the left you can see how the rounded shape works better than the flat panel.