The heart of these collectors is:
- the NARVA- vacuum tubes
- the coaxial tube
- the reflector

The experience of 40 years in the production of fluorescent lamps and test processes have been put into the development of the vacuum tubes produced by NARVA in Brand-Erbisdorf (Sachsen).

A unique manufacturing plant for vacuum tubes used for collectors originated at the headquarters of NARVA in Brand-Erbisdorf in Germany. The tubes are unrivalled with their novel glass-metal connection that NARVA has filed for patent.
Besides, the high quality tubes have proven of value through a maximum stagnation temperature of up to 300 degrees Celsius. The constant high quality is assured through a superior quality control in the manufacture.
The new high performance tubes from NARVA are produced “Made in Germany”.

With high transparent special glass, with low quantity of iron, the cladding tube is transparent for the entire solar spectrum, up to the UVB-rays and therefore suitable to turn the energy of the UV-rays into heat.

The cladding tube is covered with an anti-reflex coating, based on Nano- particles. This increases the transmission to an average of 96%, avoids decomposition and strengthens the glass additionally through closure of micro fissures.

NARVA vacuum tubes are distinguished through excellent hail impact strength.

This was tested by the TÜV-Rheinland-Group using an ice ball test according to DIN EN 12975-2:2006. In another test procedure, completely empty vacuum tubes were tested for impact strength according to the standard-design EN12975-2:2004. 150g heavy steel balls were thrown 10 times vertically on the hollow lying glass tubes. All of the samples withstood the test in the result from a falling distance of 40cm. 75% of the samples withstood the test at a falling distance of 60cm.

The knowledge of modern evacuation procedures will be used under consideration of sorption kinetic behaviour for the tubes to be evacuated.

Long years of experience with vacuum-sealed glass-metal connection guarantee long lasting vacuum sealing.
Getter keeps the vacuum strong through the entire operational period.

A novel glass-metal connection was developed and patented for the NARVA vacuum tubes: The absorber tube passes through a robust and resilient metal cap from a special aluminium alloy which is melted into the cladding tube on the outer area.

this novel glass-metal connection resist cross and shaking forces through wind strains, expansion and cavitation-impact at a high measure since the construction’s bending moments which are transferred to the absorber tubes, are absorbed in the metal and the glass is not burdened.

Furthermore, the metal caps have very small heat conductivity. This minimises heat loss. The strains of temperature change of the glass is so strongly absorbed that even a cold rain shower at stagnation point does not lead to damage.

The most modern, highly selective absorber materials with Titan-Nitrit- Oxyd- coatings by the company TINOX are used in the NARVA vacuum tubes.


The tube is a coax-distributor tube with less tube resistance. This special construction was developed especially for vacuum tube collectors and has coupling pieces for the connection of the tubes. O-rings with special temperature resistant material seal the connections. This successful construction of distribution tubes/tube connections prevents extended deep insertion of the tube into the distributor tube and works as plug-in limitation. This means that at every exit there is the same zeta-value and based on this technology a very evenly flow at every single tube is guaranteed.


Materials used with facade construction are used for the reflector. These were tested for a long time and the reflection is still maintained after 20 years.
Setup: The core layer consists of a plastic plate of Polypropylene (B2 according to DIN 4102). The strength of the plate is 1.3mm. As surface layer, an aluminium plate with 0.28 mm strength is applied on both sides.