vacuum tube for solar water heater and solar collector:

Specification:

1)Inner tube/outer tube diameter:37/47mm,47mm/58mm

2)Length of tube:1500mm,1800mm,2000mm,2100mm

3)Material:high 3.3 borocilicate glass

4)Thickness of tube:1.6mm, 2,1mm

5)Selective absorbing coating:ALN/AL -SS/CU CoatingCoating

6)Expansion coefficient:3.3*10-6

7)Excellet solar absorption:.>93%

8)Low heat reflection properties:<0.86%

9)Heat preservation:72-80 hours

10)Hail resistance:25mm

Evacuated tubes