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SOLAR WATER HEATER ACCESSORY: SOLAR VACUUM TUBE
Solar vacuum tube is the core parts of solar water heater. It absorbs solar energy converting it into heat for hot water heating. Solar vacuum tubes have already been used more than 20 years in China.
Each solar evacuated tube consists of two glass tubes made from extremely strong borosilicate glass. The outer tube is transparent allowing light rays to pass through with minimal reflection. The inner tube is coated with a special selective coating which features excellent solar radiation absorption and minimal reflection properties. The top of the two tubes are fused together and the air contained in the space between the two layers of glass is pumped out while exposing the tube to high temperatures. This "evacuation" of the gasses forms a vacuum, which is an important factor in the performance of the evacuated tubes.
| Tube Structure | All-glass double deck co-axial structure | |
| Glass material | Borosilicate 3.3 glass | |
| Outer tube diameter and glass thickness | Φ58+/-0.7mm; glass thickness 1.6+/-0.15mm | |
| Inner tube diameter and glass thickness | Φ47+/-0.7mm; glass thickness 1.6+/-0.15mm | |
| Tube Length | 1800mm | |
| Absorber coating | Coating Material | Cu/SS-AIN(H)/SS-AIN(L) |
| Sediment method | Three targets magnetron sputtering plating | |
| Absorptivity | 0.93~0.96 | |
| Emittance | ≤6.0%(80ºC+/-5ºC) | |
| Vacuum degree | P ≤5.0X10-3(Pa) | |
| Transmittance of glass tube | T ≥0.89(AM1.5 ISO9806-1:1994 | |
| Stagnation parameter | Y: 240~250 m2ºC/KW | |
| Average heat loss | ULT≤0.6 W/(m2*ºC) | |
| Hail resistance | Φ25mm | |
| Pressure endure | 0.6 MPA | |
| Cover glass tube | Protect the whole tube. The space between the cover glass tube and the inner glass tube is mechanically evacuated to create a vacuum environment |
| Inner glass tube | Filled with heat transfer fluid (generally water) and directly plugged to the water storage tank |
| Selective absorbing coating | Absorbs solar radiation and transfers to the fluid in the inner tube. |
| Retainer | Keeps the inner tube fixed. |
| Getter | Absorbs the residual air in the space between the cover glass tube and inner glass tube. |
Since its establishment in 2002, Shandong Longguang Tianxu Solar Energy Co., Ltd (hereinafter referred to as "Tianxu") has always engaged itself in the R&D, production, sales and service of high borosilicate glass tubes and new energy products including solar water heaters, solar vacuum tubes, solar heat collecting project, air source heat pump, photovoltaic products, etc.
Tianxu has 10 sets of electric furnaces, 70 sets of solar vacuum tube production line and 3 sets of solar water heater production lines. The annual output has reached one million tons of high borosilicate glass, over 16 million solar vacuum tubes makes Tianxu the largest manufacturing base of high borosilicate glass tubes and solar vacuum tubes.
In 2015, Tianxu established a joint venture company with Beijing Tsinghua Solar Co., Ltd- the solar vacuum tube technology initiator in the world. The newly established company has the world's most advanced solar vacuum tube production lines.
Our products have been widely exported to many countries, like Vietnam, India, Mexico, Syria, Korea, Dubai, Etc. we are serving the top brands in solar water heaters for each country. Our yearly export quantity is 600 containers.
