The evacuated tube is the key component to all the thermal heaters and system. It's similar to a conventional Dewar flask and consists of two borosilicate glass tubes, resistant to high chemical and thermal shock. 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 avoid heat loss in conduction and convection. The key element determines function of tube is the technology of the film coating, Gaia Solar tube is the best efficiency tube you can find in China, with the highest absorptance rate of near 97% with common rate of 94% and lowest emission rate near 3% with common rate of 5%.
|Method of Deposition||DC reactive sputtering|
|Variation along Tube Length||3%|
|Emittance ||< 6% (100°(C)|
|Vacuum Gas Pressure||£ 5 x 10-3 Pa|
|Stagnation Temperature (typical)||³ 270 °(C|
|Recommended Working Temperature||£ 150 °(C|
|Heat Loss Coefficient of Collector Tube||£ 0.85W / (M2·°(C)|
1. Higher efficiency collector, much lower heat loss with vacuum insulation
2. High pressure and super anti-freezing performance in cold weather condition
3. Less heat loss for closed loop circulation
4. No system drainage even though one or several tubes are broken
5. No risk of tube breaking from thermal shock
6. More convenient in system parts carrying and installation
3.3 high borosilicate glass tube performance and usage introduction
High borosilicate glass has first -class level of hydrolysis resistance performance high-borosilicate glass, widely used in laboratory and chemical plants, in recent years in the solar heating device on the application have developed rapidly.
High borosilicate 3.3 glass product has known as chemical stability, high voltage, resistant to thermal shock and excellent processing performance characteristics.
High borosilicate 3.3 glass production tube, the production process of every step has strict quality control, and through ISO9001 quality authentication.
Three kind of solar collector tube
1. Common: evacuated collector tubes
2. High-efficiency: Three-target evacuated collector tubes: blue and black-golden
3. High-efficiency: Three-target evacuated collector tubes: purple-golden (purple and golden)