SEIDO5----Heat Pipe Solar Vacuum Tube

Bent absorber plate
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
Higher energy gain of 10-15% per day due to semi-cylindric absorber plate
Reliable and durable


SEIDO5 is a heat pipe vacuum tube. With an outer diameter of 100 mm and a length of 2000 mm, SEIDO5 tubes have the same large dimensions as SEIDO1 tubes. The only difference between them is the profile of the absorber plate; SEIDO1 has a flat absorber, SEIDO5 has a bent or convex absorber. 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 bent absorber


Absorber area

0.225 m²


4.7 kg

Installation tilt angel

35° ~ 90°


Ø100mm x 2000mm

Collect heat pipe

Heat pipe copper Ø 8 mm

Absorber material

Copper- Aluminium 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%


< 10-5 mbar

Min. ambient tem.


Stagnation temp.


Resistance to hail