What is the meaning of vacuum tube collector?

A vacuum tube collector is a solar collector that evacuates the space between the heat absorber and the transparent cover. A water heater composed of vacuum tube collector components is a vacuum tube water heater.

Vacuum tubes can be divided into two categories according to the type of heat absorber material: one is a glass heat absorber vacuum tube (or all-glass vacuum tube), and the other is a metal heat absorber vacuum tube (or glass-metal vacuum tube). Heat pipe vacuum tube is a kind of metal heat absorber vacuum tube, which consists of heat pipe, heat absorber, glass tube and metal end cap.

Compared with other types of solar water heaters, heat pipe vacuum tube has the following irreplaceable advantages:

1. Freezing resistance: using antifreeze heat pipe, it will not freeze and crack even in severe cold conditions of -50℃.

2. Fast start-up: The heat pipe has a large heat capacity and can output heat after a few minutes in the sun; and in cloudy and sunny weather, it can produce more hot water than other water heaters.

3. No scaling: Since water does not flow directly through the vacuum tube, the problem of waterway blockage caused by scaling is avoided.

4. Good insulation: The heat pipe has the characteristic of one-way heat transfer, so that hot water will not be dissipated downward along the heat pipe to the surrounding environment at night.

5. High pressure bearing: Since there is no water in the glass tube, it can be connected to the collector with the pressure of tap water and circulating pump, so it has unique advantages in the application of large and medium-sized hot water systems.

6. Good heat shock resistance: Even if the user accidentally misoperates, the vacuum tube will not burst even if cold water is immediately injected into the water heater after being exposed to the sun.

7. Easy installation and reliable operation: The vacuum tube in the collector is "dry connection" with the collector, there is no hot water leakage problem, and it is easy to install; even if there is a problem with a heat pipe, it will not affect the normal use of the entire system during the maintenance process.

It is precisely because of the above advantages of the heat pipe vacuum tube that it has been increasingly valued by the solar industry in various countries. The heat pipe vacuum tube collector of Beijing Solar Energy Research Institute has been tested by German and Swiss testing institutions. The product thermal performance index has reached the international advanced level in the 1990s. It has become the third unit in the world that can mass-produce heat pipe vacuum tube collectors after France and the United Kingdom.

At present, the residential design in my country has not considered the supply of domestic hot water, and having hot water for bathing at home is a necessary condition for a well-off life. my country's energy supply is tight, and it is impossible to solve all the domestic hot water supply of urban residential buildings by relying on conventional energy. my country's solar energy resources are very rich. More than two-thirds of the country have an annual total radiation of more than 5.02 million kilojoules/m2 and an annual sunshine time of more than 2,000 hours; and in recent years, solar water heaters have developed rapidly, making the use of solar energy for hot water supply not only technically and economically feasible, but also competitive with conventional energy.

Solar water heaters began to be promoted in my country as early as the early 1980s, and their application scope includes collective bathrooms, swimming pool heating, industrial and agricultural production, etc. The current market development momentum is gradually tilting towards residential hot water. In some domestic areas such as Kunming, unified design and installation of solar water heaters in residential buildings have appeared one after another, achieving good social and economic benefits.

However, the promotion of solar water heaters in large and medium-sized cities such as Beijing is extremely slow. The main reason is the installation problem of solar water heaters. Since solar water heaters need to be installed on the roof, and the pipeline problem of solar water heaters was not considered in the design of residential buildings in Beijing, secondary construction is bound to be carried out. To solve this problem, solar water heaters should be made into necessary facilities for residential buildings. When designing, the pipelines of solar water heaters should be buried in the wall like heating pipes, and completed simultaneously with the main building.

Its advantages are:

1. It is conducive to energy saving and environmental protection. Each square meter of solar water heater can save 100 to 150 kilograms of standard coal per year, which can reduce the emission of greenhouse gases and dust. Auxiliary electric heating equipment is installed on the solar water heater, and supplementary heating can be carried out in winter and on cloudy days. In this way, energy saving and environmental protection can be achieved on a large scale.

2. It is conducive to building construction. Since the solar water heater and the building are unified in design and construction, secondary construction is avoided, and it can also protect the roof and increase the effect of insulation.

3. It is conducive to the beauty of the city. Solar water heater houses will form a new landscape of urban construction and beautify urban buildings.

4. Save money and be economical. The technology of solar water heaters is now basically mature. Take the heat pipe vacuum tube solar collector of Beijing Solar Energy Research Institute as an example. Its service life is 15 years. 80% of it relies on solar energy and 20% on auxiliary electric heating. The operating cost is relatively low.