Direct Flow Solar Vacuum Tube

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Direct Flow Solar Vacuum Tube

The direct flow solar vacuum tube is similar to the SEIDO1 and SEIDO5 models in terms of specifications and appearance but the heat pipe is substituted by the coaxial set of copper tubes. With the flat absorber, it has high efficiency. It also comes with high reliability and good durability. Furthermore, the module can be flexibly installed at any angle from 0° to 90° to make the absorber surface in the optimal position towards the sun. This product can be horizontally mounted on flat roofs or integrated into the facade of buildings, meeting the requirements of modern architecture.

Technical Specifications

Specification Direct flow evacuated tube
Absorber area 0.173 m2
Weight 4.6 kg
Installation tilt angle 0° ~ 90°
Dimension Ø100mm×2000mm
Flow-through pipe Inner copper pipe: Ø 8mm
Outer copper pipe: Ø 12mm
Absorber material Copper- Aluminum Sunstrip,
0.47 mm thickness
Selective coating Aluminum nitride Al-N-O selective coating
Absorptance : a > 0.94
Emittance : e < 0.06
Glass tube material Borosilicate glass
Thickness: 2.8 mm
Transmittance of glass: 91%
Vacuum < 10-5 mbar
Min. ambient temperature -45℃
Stagnation temperature 276℃
Resistance to hail 11J+-1J

Working Principle
In this direct flow solar vacuum tube, the process from heat transfer to the heat circulation is done by applying the direct flow. This means that the medium is directly heated without the help of any intermediate heat transfer unit, like heat pipe. To be specific, the heat transfer liquid flows through a concentric copper tube which is incorporated into the absorber. Such absorber picks up thermal energy by direct heat exchange. Inducted through the inner copper pipe, the cold liquid returns to the space between the inner and outer copper pipes. The inlet and outlet pipes of each collector pipe are linked to the manifold. All the pipes are arranged in parallel.

This direct flow solar vacuum tube has higher requirements for the usage and installation. Owing to the scaling problem, it uses the secondary circuit system instead of the system directly heating the water. The antifreeze liquid is adopted as the thermal conductivity medium of the solar energy circuit. In case of liquid leakage, the whole system has to be cut off for repair. So under such circumstances, the system fails to consistently work.

Though similar to the SEID01 type in a certain degree, the direct flow solar vacuum tube is deigned with 2 copper pipes with the diameter of the inner pipe being 8mm and of the outer one being 12mm. Such design greatly improves the heat transfer capability. To guarantee the vacuum degree of the tubes less than 10-5mbar, the metal materials are all degassed before they are installed. Moreover, this product is able to supply power for relevant devices by absorbing the solar energy.

Sunda is an experienced direct flow solar vacuum tube manufacturer and supplier in China. We provide various types of products such as heat pipe solar vacuum tube, flat plate solar water heater, and heat pipe evacuated tube solar collector.

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