1.All Glass Vacuated Tube All glass evacuated tubes are the key component of solar collectors. The evacuated tube is similar to a conventional Dewar flask and consists of two borosilicate glass tubes, a glass with high chemical and thermal shock resistance. The outer side of the inner tube is coated with a sputtered solar selective surface. This coated inner tube is closed at one end and sealed at the other end to the outer tube. The annular space between the outer tube and inner tube is evacuated to virtually eliminate heat loss by conduction and convection. We use the tubes which use the successfully developed innovative Advanced Solar Selective Coatings in commercial scale, which achieve the highest thermal efficiency and good thermal stability. Solar selective coatings absorb most solar radiation while simultaneously suppressing the thermal emittance loss from coating surfaces. They vary mainly in their optical property and thermal stability. Excellent results have been obtained by using DC magnetron sputtering technology. A solar absorbance of 0.94 - 0.96 with an emittance of 0.04 - 0.06 at 100 centigrade has been achieved. Models º¦47í-150 º¦58í-180 Weight 1.35í+0.12kg 2.29í+0.18kg Structure All glass coaxial double-layer tubes All glass coaxial double-layer tubes Outer tube diameter º¦47í+0.7mm º¦58í+0.7mm Inner tube diameter º¦37í+0.7mm º¦47í+0.7mm Outer Tube thickness 1.6í+0.15mm 1.8í+0.15mm Inner tube thickness 1.6í+0.15mm 1.6í+0.15mm Tubes length 1542í+4mm 1812í+4mm Material of coating AlN/AIN-SS/Cu AlN/AIN-SS/CU Absorptance 0.94~0.96 0.94~0.96 Emittance 0.04~0.06 0.04~0.06 Vacuum Pí_5í-10-3pa Pí_5í-10-3pa Transmittance of Outer Tube 0.91 0.91 Stagnation temperature (height) 270~300íµ 270~300íµ Heat-loss coefficient í_0.6w/ m2*íµ) í_0.6 w/ (m2*íµ). Bearing hailstone ability hailstone diameterº¦25mm hailstone diameterº¦25mm. Pressure-endure ability 1MPa 1MPa.