Introduction to the Structure of Refrigerators

From a structural perspective, freezers generally include a box, refrigeration system, and electrical system.
refrigeration system
The basic function of an freezer is to cool and maintain an appropriate low temperature inside the box. A refrigeration system generally consists of four basic components: a compressor, a condenser, a capillary or thermal expansion valve, and an evaporator. Refrigerant is a liquid that can boil at low pressure and absorb heat during boiling. The refrigerant continuously circulates in the refrigeration system, and the compressor increases the gas pressure of the refrigerant, causing liquefaction conditions. When it passes through the condenser, it condenses and liquefies to release heat. Then, when it passes through the capillary, it reduces pressure and temperature, and then boils and vaporizes to absorb heat through the evaporator. In addition, refrigeration diodes are now developed and used without complex mechanical devices, However, it has poor performance and is suitable for small refrigerators.
The refrigerator used F12 (Freon 12) as refrigerant, but now it uses R600a/R134a/R404 and other refrigerants because it will destroy the ozone layer of the atmosphere.
In addition, due to the inevitable presence of some moisture and impurities in the system, a drying filter is generally installed at the inlet end of the capillary tube.
electrical system
Refrigerators use electricity as their main energy source, relying on electric motors to drive compressors or refrigeration diodes. They are usually equipped with relay protectors and temperature controllers.
According to different starting methods, refrigerator motors using compressors can be divided into resistance split phase starting, capacitor starting, and capacitor running starting. The motor of a fully enclosed compressor is installed inside the refrigeration system, which is in long-term contact with refrigerant and refrigerant oil, and can withstand pressure, high temperature, etc. Therefore, it must have requirements such as resistance to refrigerant and refrigerant oil, stable electrical performance, high temperature resistance, vibration and impact resistance, high starting torque, and cleanliness without moisture.
Box
The box is composed of structural materials and insulation materials, forming a space for storing food and preventing heat transfer inside and outside. The box generally includes an outer box, an inner liner, and an insulation layer. The inner liner of a refrigerator is generally vacuum formed from ABS or HIPS sheets, with a thickness of less than 1mm, white and smooth. Polyurethane foam is widely used as insulation material, which has excellent insulation performance and little change in thermal conductivity after long-term use.
Some are equipped with separate cold storage rooms or ice storage rooms, while others have both. Nowadays, some refrigerators are even divided into four compartments to store various types of food:
Freezing: -18 ° C (0 ° F)
Meat: 0 ° C (32 ° F)
Refrigeration: 4 ° C (40 ° F)
Vegetables: 10 ° C (50 ° F)
The capacity of a refrigerator is calculated in liters or cubic feet. A typical refrigerator has a freezer capacity of 100 liters and an ice storage compartment of 140 liters.
(Selected from Baidu Baike)