Just like an automobile engine,the computer CPU,vacuum tube is the core component of the solar water heater. Its performance lies on the actual film coating technology. SIDITE Company adopted a new graded coating technology of Qinghua University,and tube raise the heat.
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Specification of basic vacuum tubes
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Tube
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Standard Tube (Normal tubes)
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Tri-tuble (Three high tube)
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Specification
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Model 47*15
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Model 58*18
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Model 47*15
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Model 58*18
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Length
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1500mm
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1800mm
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1800mm
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1800mm
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Outer tube diameter
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47mm
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58mm
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47mm
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58mm
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Inner tube diameter
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37mm
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47mm
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37mm
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47mm
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Weight
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1.3kg
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2.2kg
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1.3kg
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2.2kg
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Glass thicknes
(Inner Tube) |
1.6mm
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1.6mm
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1.6mm
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1.6mm
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Glass thicknes
(outer Tube) |
1.6-2.0mm
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1.6-2.0mm
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1.6-2.0mm
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1.6-2.0mm
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Glass material
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Borosilicate
Glass 3.3 |
Borosilicate
Glass 3.3 |
Borosilicate
Glass 3.3 |
Borosilicate
Glass 3.3 |
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Coating material
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AI-A-AI
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AI-A-AI
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AIN-SS-Cu
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AIN-SS-Cu
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Coating position
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Outer surface of
inner tube |
Outer surface of
inner tube |
Outer surface of
inner tube |
Outer surface of inner tube
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Deposition Method
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DC reactive
sputtering |
DC reactive
sputtering |
DC reactive
sputtering |
DC reactive
sputtering |
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Absorption ratio
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≥91%
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≥91%
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≥94%
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≥94%
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Reflection ratio
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≤7%
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≤7%
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≤6%
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≤6%
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Vacuum degree
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3.0T2-3Pa
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3.0T2-3Pa
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8.0T2-4Pa
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8.0T2-4Pa
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Thermal expansion
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3.3*10-6/0C
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3.3*10-6/0C
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3.3*10-6/0C
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3.3*10-6/0C
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Stagnation parameter
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220m2 °C/KW
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220m2 °C/KW
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220m2 °C/KW
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220m2 °C/KW
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Solar rediamce exposure
for obtaining a present water temperature |
4.6MJ/m2
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4.4MJ/m2
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3.9MJ/m2
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3.6MJ/m2
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Average heat loss
coefficient |
0.75w/(m2.°C)
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0.73w/(m2.°C)
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0.67w/(m2.°C)
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0.62w/(m2.°C)
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Max pressure
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0.6MPa
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0.6MPa
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0.6MPa
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0.6MPa
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Minimum temperature
endurable |
–35°C
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–35°C
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–40°C
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–40°C
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Hailstone endurable
(diameter) |
Less than D25mm
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Less than D25mm
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Less than D25mm
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Less than D25mm
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Maximum temperature
endurable |
270°C
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270°C
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300°C
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300°C
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Lifetime
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15 years
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15 years
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15 years
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15 years
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