The freezer is between 0 and -5 degrees.

The freezing room should be between-16 degrees and -24 degrees.

Refrigerator is a kind of refrigeration equipment to keep a constant low temperature, and it is also a civilian product to keep food or other items at a constant low temperature. There are compressors, ice makers, cabinets or boxes for refrigeration, and there are storage boxes with refrigeration devices in the boxes.

The volume of domestic refrigerators is usually 20 ~ 500 liters. 19 10 the world's first compressed refrigeration household refrigerator came out in the United States. 1925 Lido Company of Sweden has developed a household absorption refrigerator. 1927 the general electric company of the United States has developed a fully enclosed refrigerator. 1930, air-cooled continuous diffusion absorption refrigerators with different heating methods were put on the market. 193 1 year, a new refrigerant freon 12 was successfully developed. Domestic thermoelectric refrigerators began to be produced in the second half of 1950s, and refrigerators began to be produced in China in 1950s.

Extended data:

According to the classification of boxes, the working principle is as follows:

1) compression refrigerator: this refrigerator is provided with mechanical energy by a motor and works on the refrigeration system through a compressor. The principle of refrigeration system is that the refrigerant with low boiling point absorbs heat when it evaporates. Its advantages are long service life and convenient use. 9 1 ~ 95% refrigerators in the world belong to this category. Commonly used refrigerators use a refrigerant called R600 refrigerator A as a hot "porter" to "carry" the heat in the refrigerator to the outside of the refrigerator.

2) absorption refrigerator: this refrigerator can use heat sources (such as gas, kerosene, electricity, etc.). ) as a driving force. Ammonia-water-hydrogen mixed solution realizes refrigeration in the process of continuous absorption-diffusion. Its disadvantages are low efficiency and slow cooling, which has been gradually eliminated.

3) Semiconductor refrigerator: It is a refrigerator that produces Peltier effect at the junction by applying direct current to PN semiconductor.

4) Chemical refrigerator: It is a refrigerator that uses some chemicals to absorb heat strongly when they are dissolved in water to obtain refrigeration effect.

5) Electromagnetic vibration refrigerator: It is a refrigerator with electromagnetic vibration machine as the main power to drive the compressor. Its principle and structure are basically the same as that of the compression refrigerator.

6) Solar refrigerator: It is a refrigerator that uses solar energy as refrigeration energy.

7) adiabatic demagnetization refrigeration refrigerator.

8) Radiant refrigeration refrigerator.

9) Solid refrigeration refrigerator.

References:

Baidu encyclopedia-refrigerator