evacuated solar collector tubes

General solar collector tube is
1)higher absorptance ,lower emittance
2)reliable quality,reasonalbe price
3)warranty 15 year






solar collector tube Parameter:

Configuration
General solar collector tube
Material
Borosillicate glass
Glass thermal expansion coefficient
3.3×10-6
Diameter of cover tube
47mm/58mm
Diameter of inner tube
37mm/47mm
Thickness of glass
1.6mm
Transmittance of cover tube
0.91
Length
1200 / 1500 /1800mm
Solar selective absorbing coating
Graded Al-N/Al selective surface, sputtering
Solar absorptance(AM1.5)
0.9
Emittance(80)
0.08
Stagnation Temperature
≥200
Heat loss coefficient
≤0.80W
Impact resistance
Withstand hailstone of 25 mm in diameter
Strength(pressure tested)
1MPa