This kind of tube is made of two layers of borosilicate glass which is specially hard. Borosilicate glass 3.3 is an ideal material for solar evacuated glass tube because it has high transparency and can withstand high temperature as well as high pressure.

The absorber layer is coated with stainless steel, aluminum and copper in an environment of entire nitrogen. The selective coating is more stable when stainless steel is added, and the absorptance is higher. Since copper is more effective than aluminum in reducing radioactive heat loss, so heat loss is greatly cut down when copper is coated as the infrared-reflection layer.

The vacuum jacket which is of high vacuum degree is a kind of superior insulation. It reduces heat loss and protects the water in the tube from freezing.

Solar evacuated glass tube can produce hot water even in tough weather. That’s why it is suitable to be used in areas and regions where is very cold or always cloudy.

Technical Specification

1.Structure: Two concentric borosilicate glass

2.Material: Borosilicate glass 3.3

3.Glass thickness: 1.6mm

4.Thermal expansion: 3.3 × ***6°C

5.Outer/Inner tube diameter: *7mm/*7mm

                      *8mm/*7mm

6.Outer tube diameter×Length: *7mm×***0m/***0mm/***0mm

                        *8mm×***0mm/***0mm/***0mm/***0mm/***0mm

7.Selective coating: SS-AlN/Cu

8.Absorptance: 0.***0.*5(AM1.5)

9.Emittance: 0.*4~0.*6(*0°C**5°C)

*0.Vacuum degree: P≤5.0×***3 (Pa)

*1.Stagnation temperature: **0~**0°C

*2.Heat loss: ULT= 0.4~0.6w/(m2.°C)

*3.Resistance: Hail diameter≤ *5mm

*4.Solar irradiation for obtaining a preset water temperature rise in an all-glass evacuated solar collector tube under stagnation: H=3.7~4.2 MJ/m2(*8mm); H=2.9~3.2MJ/m2(*7mm)