Structure 

All-glass concentric dual tube geometry

 Glass material

Borosilicate glass 3.3

Outer tube diameter 

F=58±0.7mm 

 Inner tube diameter

F=47±0.7mm 

 Glass thickness

1.6mm 

 Tube length

1500±5mm/1800±5mm or as particular order 

Absorbing coating properties

 Configuration

1500±5mm/1800±5mm or as particular order 

 Construction

Graded Al-N-Al solar selective absorbing coating 

Method to deposition 

3 target DC magnetron sputtering

Absorption 

>92% 

Emittance 

 <8%(80°C)

 Vacuum

P<5×10-3 Pa

 Stagnation parameter

 >250°C/KW

 Solar radiance exposure for obtaining a preset water temperature

 <3.7MJ/

 Average heat loss coefficient

<0.8W( C) 

 Lifetime

 =15years