... special technology; high absorptive;low emission vacuum tube with Heat pipe for solar collector has the following advantages: 1) ... winter. vacuum tube with Heat pipe for solar collector specification:Manifold material and thicknessA, Black or silver aluminum alloy , thickness ... pressure 9Bar, work pressure 6bar Frame material and thicknessA, Aluminum alloy , thickness 2.0mmB, Stainless steel, thickness ...