hard borosilicate solar evacuated tube

The marerial of glass tube: hard borosilicate :3.3
The thickness of inner and outer tube of:1.6mm
Absorption coefficient:
specification:
The marerial of glass tube: hard borosilicate :3.3
The thickness of inner and outer tube of:1.6mm
Absorption coefficient: 93%
Absorptive coating :high efficient heat absorptive selective sputtering coating:
SS-C/CU&AL/AN
Emission coefficient: 10%(8%)
Evacuated : 5*10-3pa
Stagnation temperature: 220 °C
Hail resistance: 25m
Freezing resistance:-35 °C
Structure

Dual concentric geometry tube
Material of glass
hard borosilicate:3.3
Diameter and thickness of outer tube
Ø58±0.5mm * 1.6mm
Diameter and thickness of inner tube
Ø47± 0.5mm *1.6mm
Length of vacuum tube
1800mm(±10mm)
Properties of absorptive coating
Coating method
selective absorptive sputtering coating:
SS-C/cu & AL/N
Transmissivity t 0.89(AM1.5)
0.913
Absorptance 0.86(AM1.5)
0.930
Emissivity εh 0.080(30°C±5°C)
0.026
Pressure of vacuum tube p 5×10-2 Pa
5×10-3Pa
Stagnation parameter Y 250sqm·°C/kW
246.3
Solar radiance H 4.7MJ/m²
4.59
Average heat loss coefficient ULT 0.8W(sqm·°C)
0.721
Lifetime
15 years