The evacuated tubes consists of two concentric glass tubes which are sealed in a semi-circular shape on one side and are joined to one another on the other side. The space between the tubes is evacuated and hermetically sealed (evacuated insulation). To use solar energy, the internal glass tube is coated with an environmentally friendly, highly selective layer on the outside, thus turning it into an absorber. The selective coating is protected in the evacuated space. The aluminum nitride sputter coating used is characterized by an extremely low emission and a high absorption rate.
All-glass double deck co-axial structure
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
Three targets magnetron sputtering plating
Transmittance of glass tube
T ≥0.89(AM1.5 ISO9806-1:1994
Y: 240~250 m2ºC/KW
Average heat loss
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.
Keeps the inner tube fixed.
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.
Packaging & Shipping
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.