solar vacuum tube

Fine tubes make fine water heater. Technical Performance:Item One-targetThree-targetAbsorption of Selective CoatingAM1.5≥94.5%≥95.5%Emission of Selective Coating80±5≤6.5%≤5.5%Stagnation Temperature220m2/KW≥260m2/KWSolar Irradiation for Water Temperature Rise≤2.9MJ/ m2≤2.8MJ/ m2Coefficient of Average Heat Loss≤0.65W/(m2 .)≤0.60W/(m2 .)Structure of Selective CoatingAl-N/AlCr-Al-N/CuVacuum≤3.0*10-3PaMaximum Strength0.6 MPaRatio of Solar Transmission≥0.89 ( AM 1.5 ISO9806-1: 1994) In term SpecificationDiameter of Outer/Inner TubeΦ47/37Φ58/47Φ70/58Length of Tube1200, 15001600, 180019201500, 1600, 18001920, 2000,1500,1800Thickness of Tube1.60±0.15 Note: The length of the tubes can be adjusted from 1200mm to 2000mm according to the buyers requirement.