The marerial of glass tube: Hard borosilicate: 3.3

The thickness of inner and outer tube of: 1.6mm

Absorption coefficient: 88%

Absorptive coating: High efficient heat absorptive selective coating:

AL-N/AL

Emission coefficient: 10%(8%)

Evacuated: 5*10-3pa

Stagnation temperature: 220 degrees celsius

Hail resistance: 25mm

Freezing resistance: -35 degree celsius

Structure Dual concentric geometry tube

Material of glass hard borosilicate: 3.3

Diameter and thickness of outer tube Ø 58± 0.5mm& 1.6mm

Diameter and thickness of inner tube Ø 47± 0.5mm& 1.6mm

Length of evacuated tube 1800mm(± 10mm)

Properties of absorptive coating Coating method selective sputtering absoptive coating: AL-N/AL

Transmissivity t≥ 0.89(AM1.5) 0.918

Absorptanceα ≥ 0.86(AM1.5) 0.883

Emissivity ε h≤ 0.080(30degree± 5degree) 0.041

Pressure of evacuated tube: p≤ 5× 10-2 Pa 5× 10-3 Pa

Stagnation parameter: Y> 190sqare meter• degree/kW 223.8

Solar radiance: H< 4.7MJ/m² 4.61

Average heat loss coefficient: ULT< 0.8W(square meter• degree) 0.792

Lifetime: 15years