SEIDO1----Heat Pipe Solar Vacuum Tube

Flat plate absorber
High efficiency under low ambient temperature due to ultra high vacuum
Fast start-up due to small thermal capacity of working fluid
Low heat losses due to thermal diode effect
No corrosion or scaling problems due to patented thermo-compression sealing technology

Easy installation and maintenance
High system operation pressure resistance and thermal shock resistance
Higher energy through heat transmission by working fluid compared to thermal conduction
Reliable and durable


SEIDO1 is a heat pipe vacuum tube with a flat absorber profile. SEIDO1 tubes have large dimensions with an outer diameter of 100 mm and a length of 2000 mm. The heat transfer from the absorber to the heat circulation is performed by the heat pipe which is mounted in the absorber. This heat pipe had originally been developed for the thermal control in satellites. Inside the pipe, the heat is conducted with high efficiency to its upper end. From there it is released to the heat circulation. Although the heat transport medium of the heat pipe is water the heat pipe is a closed system. The pipe is charged with a small amount of water and carefully evacuated before sealing.
Since the heat transfer liquid of the heat circuit does not flow through the collector itself, installation is very simple and an exceptionally trouble-free operation is guaranteed. The operation of the system will not be interrupted even if one of the collector tubes should get damaged.

Technical data




Heat pipe vacuum tube with flat absorber


Absorber area

0.173 m²


4.6 kg

Installation tilt angel

15° ~ 90°


Ø100mm x 2000mm

Heat pipe

Heat pipe copper Ø8 mm

Absorber material

Copper- Aluminium sunstrip, 0.47 mm thickness

Selective coating

Aluminum nitride Al-N-O selective coating; Absorptance: a > 0.94; Emittance: ε < 0.06

Glass tube material

Borosilicate glass
Thickness: 2.8 mm
Transmittance of glass: 91%


< 10-5 mbar

Min. ambient tem.


Stagnation temp.


Resistance to hail