Normal Vacuum Tube
Vacuum tube introduction:
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.
Vacuum tube is the absorber of solar water heater. They absorb solar energy converting it into heat for use in water heating. Vacuum tubes have already been used more than20 years in China, also in other country. There are several types of vacuum tubes in use in the solar industry. Jinyi company use the most common "twin-glass tube". This type tube is chosen for its reliability, higher performance and low manufacturing cost.
Vacuum tube is the absorber of solar water heater. They absorb solar energy converting it into heat for use in water heating. Vacuum tubes have already been used more than20 years in China, also in other country. There are several types of vacuum tubes in use in the solar industry. Jinyi company use the most common "twin-glass tube". This type tube is chosen for its reliability, higher performance and low manufacturing cost.
1. Excellent performance of absorbing, but low heat loss, Especially adapted to sever cold regions,(super heat preservation).
Jinyi successfully introduced the Advanced Solar Selective Coating, which achieves the greater thermal efficiency and better thermal stability innovatively. The solar selective coating absorbs most solar radiation as well as suppresses the thermal emittance loss from the coating. With the help of DC magnetron sputtering technology, the absorptance of 0.88 - 0.92 and emittance of 0.04 - 0.08 has been achieved. The main absorbing wavelength ranges from 0.35μm to 3.0μm.
Vacuum tube efficiency curve
2. Excellent resistance of burst.
Improved molecule structure of plated selective coating, attributed to DC magnetron sputtering technology, makes the highest of vacuum tube working temperature as high as 300℃, effectively preventing the coating from bursting, aging, discoloring, function attenuating because of long time burn under the sun, prolonging its life span to 15 years.
Furthermore, the special material plated on tube coating is activated promptly once sun irradiate. The upper surface of semi-cylinder of tube heated by sunshine directly, and the under surface heated by reflected ray at the same time, have different temperatures, so the thermal force propels the water to cycle in the tube rapidly. Consequently, the water circulation in the tube which is made of toughened high borosilicate 3.3 glass balances the temperature and prevents tube from burst.
3. Excellent resistance of corrosion, long life span ( up to 15 years)
Standard PYREX high borosilicate glass with coefficient of linear expansion 3.3×10-6/℃, complies with international ISO1776 acid proof Grade 1, ISO695 alkali proof above Grade 2. It can resist the hailstone with Diameter 25mm, resisting pressure 1MPa.
4. Reducing the fouling on the tube wall, keeping water clean.
5. Evacuated tubes are aligned in parallel, the angle of mounting depends upon the latitude of your location. In a North South orientation the tubes can passively track heat from the sun all day. In an East West orientation they can track the sun all year round.
6. The efficiency of a evacuated water heater is dependent upon a number of factors, one important one being the level of evacuated radiation (insolation) in your region.
Vacuum tube diagram
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