What is a 3-layer vacuum tube? What is the effect of the water heater structure?

The 3-layer vacuum tube is a necessary part of the water heater when using solar energy. Join Tnhelearning.edu.vn to find out what a 3-layer vacuum tube really is, and how does it work in the structure of a water heater?

What is a 3-layer vacuum tube?

The 3-layer vacuum tube is a vacuum heat-absorbing tube made of transparent glass outside (with heat resistance, high strength), in the middle is a vacuum , and the inner body of the tube is specially plated with 3 layers :

• The outermost layer is an anti-reflective aluminum layer , helping to minimize sunlight reflection.
• The next inner layer is the Titanium layer that has the ability to absorb heat to the maximum extent.
• The innermost layer is the heat transfer layer – made of copper for the most efficient hot water.

What is the effect of the 3-layer vacuum tube in the structure of the water heater?

The 3-layer vacuum tube is an important part of a solar water heater. Depending on the capacity, the water heater has an appropriate number of glass tubes to collect vacuum heat. For example, Ferroli solar water heater has a capacity of:

• 160 liters: there are 12 glass tubes
• 180 liters: there are 14 glass tubes
• 200 liters: there are 16 glass tubes

These vacuum collector glass tubes are attached to the hot water tank through holes in the tank body. They are responsible for absorbing and transferring heat to heat water.

When you turn on the water source to supply water to the tub, the water will overflow and fill the entire inner wall of the vacuum glass tube (that’s why the glass tubes are sloped at an angle to the horizontal).

When there is no sunlight, the temperature of the water in the glass tube will be the same as the temperature of the water in the tank.

When there is sunlight, the sunlight will pass through the glass tube and then enter the heat-absorbing layer – causing the inside of the tube to heat up, then impact the heat transfer layer, causing the water contained in the tube to also be heated. .

According to the principle of thermal convection, when the liquid is at high temperature, it will tend to move up, and when it is at low temperature, it will move down. Therefore, the hot water in the glass tube will be moved to the top of the tank, and then the cold water inside the tank will move down through the glass tube. The process of making hot water will temporarily end when the water temperature in the container and the vacuum tube are equal.