154-solar vacuum tube

solar vacuum tube 1.Structure: All-glass double-tube co-axial structure; 2.Glass material: High borosilicate 3.3 glass; 3.External pipe diameter : Φ=47 ;Φ=58;Φ=70 4.Internal pipe diameter and thickness: Φ=37;Φ=47;Φ=58 5.Pipe length: 1500mm;1600mm;1700mm,1800mm;1900mm;2000mm;2100mm 6.Absorptive coating property: Structure: Al/Cu/SS 7.Absorption ratio: As=0.90 0.93(AM1.5) 8.Emission ratio: 0.04 0.06(80±5) 9.Vacuum tightness: P≤5x10-3 (Pa) 10.Idle sunning property parameters: Y=260 300m2 . /KW 11.Solar irradiation for obtaining a preset water temperature: H≤4.7MJ/m2 (Φ58) H=3.7 4.2 MJ/m2 H≤3.7MJ/m2 (Φ47) H=2.9 3.2 MJ/m2 12.Average heat loss coefficient:ULT=0.4 0.6W/( m2 . )