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Special features of vacuum tube solar water heater

Views:1     Author:Site Editor     Publish Time: 2020-01-31      Origin:Site

Due to the continued lack of resources, countries have begun to develop new resources. Solar energy is another major resource that has been discovered. Today, vacuum tube solar water heatersare emerging for a wide variety of people. Therefore, various vacuum tube solar water heaters have appeared on the market, including vacuum tube solar water heaters.


Core component

Vacuum tube characteristics



Core component

The vacuum tube is the core of the vacuum tube solar water heaters. His structure is like an elongated thermos bottle with a vacuum between the inner and outer layers. A spectrally selective absorbing coating apply to the surface of the inner glass tube using a special process to maximize the absorption of solar radiant energy. After sunlight, the photons hit the coating, and the solar energy convert into heat energy. The water absorbs heat from the outside of the coating; the water temperature rises; the density decreases; the hot water moves upward, and the cold water drops.


The hot water is always in the upper part, the water tank. The temperature rise of hot water in solar water heaters has little to do with external temperature, mainly depending on the light. When opening any tap in the kitchen or bath room, the hot water in the water heater will flow out due to the natural drop. The larger the drop, the higher the water pressure. At present, the domestic enterprises that produce rough tubes mainly include companies such as Linuo, Yuansheng, and Huihui. 

The enterprises that produce vacuum tubes mainly include enterprises such as Xinnuo New Materials and Baoguang Collecting Heat Pipes. There are two main types. One is that there is no water in the pipe. First, the water inside the pipe, the traditional vacuum pipe is the water inside the pipe. The introduction of double vacuum and the introduction of the "heat pipe in-line" vacuum tube make the glass pipe not water.


As the heart of vacuum tube solar water heaters, vacuum tubes will change with the changes of the environment. Because regional differences, differences in target consumer groups. And differences in construction require that vacuum tube solar water heaters integrate with buildings in response to local conditions effectively.


Vacuum tube characteristics

The three high "solar core" vacuum tube is different from the ordinary tube in that the heat absorbing film layer is different (the heat absorbing film layer is a key part of the vacuum tube). The three high tubes are interference films, and the ordinary tubes are graded films. The difference between them is mainly the difference between the interference film and the grading film.

The fundamental difference:

The structure of the film is different, which leads to different principles of absorbing the sun's rays. The grading film is a multi-layer film whose absorption layer is generally 9 layers. Which absorbs the solar rays layer by layer, and its absorption of light gradually becomes higher. Due to this gradual structure, the emission ratio increases with temperature, so that the emission ratio is greatly increased when the operating temperature is 300 to 500 °C. 

Moreover, the aluminum ions in the absorption layer are greatly enhanced in activity at a high temperature and drift. The internal structure of the film layer is disordered, causing the film layer to begin to age. After being in such a high temperature for a long time, the film layer will fall off, thereby affecting the heat collecting efficiency and life of the vacuum tube.

The interference film has a total of two layers of the absorption layer. Interference occurs between the two films due to the different ratio of the metal components. So that the absorption ratio is increased and the emission ratio is lowered. In addition, the anti-reflection layer reduces the reflection effect, thereby achieving a higher absorption ratio and a lower emission ratio, and greatly improving the heat collection efficiency.



The absorption ratio of the three high tubes is increased by 12%, the emission ratio is reduced by 30%-40%, the absorption is low, the heat loss is small, and the heating is fast. High-efficiency tube, super-absorption, high thermal efficiency, fast heating, under the same lighting conditions, more hot water than the ordinary tube; the cold tube, due to the emission ratio of copper ion is lower than aluminum ion 0.2. Therefore, the heat loss is very small, and it can still work normally in the cold environment, and the hot water is usually taken at -30 °C.



High-temperature special effect tube, high-cold tube and high-efficiency tube respectively adopt three-target, double-target, single-target magnetron sputtering process; common tube generally adopts single-target magnetron sputtering process.


A. Nozzle, where the film layer is sealed at a temperature of 800 ° C or higher, part of it is inevitable. Due to the high temperature resistance, the high-temperature special effect tube has only a film length of about 1 cm, while other tubes are not resistant to high temperature, and the film peeling length is about 2.5 cm. 

B. Color of inner tube: Observed with the naked eye, the color of the inner tube of the high temperature and cold tube is dark red ; and the high efficiency tube and the ordinary tube are white.



If you want to buy a vacuum tube solar water heater, after reading this article you will understand its special features, you will also be able to pick out the vacuum tube solar water heater you want.


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