Vacuum cooling principle and characteristics

- Jun 05, 2019-

Vacuum cooling is based on the fact that vapor water molecules have higher energy than liquid water molecules. Therefore, water must absorb latent heat of vaporization when vaporized, and its latent heat of vaporization will increase as the boiling point decreases. The material is placed in a closed vacuum chamber that can withstand a certain negative pressure and is pumped by a suitable vacuum system. As the vacuum in the vacuum chamber is continuously increased, the boiling temperature of the water is continuously lowered, and the water becomes easily vaporized. When the water is vaporized. The heat can only be absorbed from the object itself, and the object to be treated can be quickly cooled.

In daily life, at one atmosphere (101 325 Pa), water boils at 100 °C. However, the boiling temperature of water is not constant and decreases (or increases) as the pressure decreases (or increases). For example, the boiling temperature of water is 76 °C at 40 196.6 Pa, 29 °C at 4 kPa, and 14 °C at 1.6 kPa. The lowering of the boiling point makes the water easy to vaporize. Since vapor water molecules have higher energy than liquid water molecules, water must absorb latent heat of vaporization when vaporized, and its latent heat of vaporization increases as the boiling point decreases. According to this principle, the object to be treated can be placed in a closed vacuum box that can withstand a certain negative pressure and pumped by a suitable vacuum system. As the vacuum in the vacuum box is continuously increased, the boiling temperature of the water is continuously lowered. It becomes easy to vaporize, and when water vaporizes, it can only absorb heat from the object itself, and the treated object can be quickly cooled.