all-glass vacuum tube

2.35kg

1.35kg

Net weight

>200

>200

Stagnation Temperature

P<5x10^-2Pa

P<5x10^-2Pa

Vacuum

<8%

<8%

Emission coefficient

>92%

>92%

Absorption coefficient

AL/N/AL

AL/N/AL

Absorptive Coating

Borosilicate Glass 3.3

Borosilicate Glass 3.3

Material

3.3x10^-6

3.3x10^-6

Thermal expansion

1.6mm

1.6mm

Glass thickness

47mm

37mm

Inner tube diameter

58mm

47mm

Outer tube diameter

1800

1500mm

Length

TG58

TG47

Model tape

Technical data table

These tubes perform very well in overcast conditions as well as low temperatures. Because the tube is 100% glass, the problem with loss of vacuum due to a broken seal is greatly minimized. Glass-glass solar tubes may be used in a number of different ways, including direct flow or heat pipe configuration.

Consists of two glass tubes which are fused together at one end. The inner tube is coated with a selective surface that absorbs solar energy well but inhibits radiative heat loss.
The air is withdrawn ("evacuated") from the space between the two glass tubes to form a vacuum, which eliminates conductive and convective heat loss.

All-glass vacuum tube :