Refrigerator working principle and classification

Generally speaking, chest freezer are composed of four major parts, namely compressor, condenser, expansion valve and evaporator. According to needs, you can choose to install auxiliary devices such as pressure controllers, temperature controllers, and filter driers.

The refrigeration process of a compression refrigerator: firstly, the gaseous refrigerant is compressed by the compressor to form high-pressure and high-temperature steam and discharged into the condenser. Since the room temperature is lower than the critical temperature of the refrigerant, it will liquefy when it reaches the required pressure. A large amount of heat is released, and the heat is dissipated into the air through radiating pipes and fins. After the heat is dissipated, the temperature is reduced to close to room temperature, and it is converted into a low-temperature and high-pressure liquid refrigerant after cooling by the condenser. Through the expansion valve, because the refrigerant flowing out of the expansion valve is contained, it becomes low-temperature and low-pressure liquid and gas, which enters the evaporator, while absorbing the heat in the refrigerator, turning it into saturated steam, and then compressing by the compressor, releasing heat into the evaporator. The liquid continuously circulates to form a circulating refrigeration system. Its advantages are long life and convenient use. 91-95% of refrigerators in the world belong to this category.

(1) Divided by control system
1. Mechanical temperature control: mechanically adjusting the temperature of the refrigerator is the earliest and simplest method of temperature control, which can ensure that food does not deteriorate and meet the needs of food preservation.
2. Electronic temperature control: The temperature in the box is controlled by an electronic temperature probe, which is sensitive and accurate. The refrigeration system is a single cycle, which cannot adjust the temperature of the refrigerating room and the freezer separately. It can only fuzzy control and display the temperature, but cannot adjust the temperature manually.
3. Computer temperature control: The entire system is controlled by a computer, and the temperature is stable and accurate. The refrigerator with solenoid valve has dual circulation loops, dual temperature and dual control, which can adjust the refrigerator compartment separately. Freezer temperature. The control system has artificial intelligence, and the microcomputer chip accurately calculates the working parameters of the refrigerator, runs automatically, and precisely controls the temperature.

(2) Divided by climate type
According to the climate environment used, household refrigerators can be divided into four types: subtropical type ST, the ambient temperature is 18-38℃; tropical type T, the ambient temperature is 18-43℃; subtemperate type SN, the ambient temperature is 10-32℃, temperate type N, ambient temperature is 16-32℃.

(3) Divided by freezing capacity
It can be divided into: one-star, two-star, three-star, and three-star with freezing capacity.

(4) Divided by purpose
It can be divided into refrigerator (BC), freezer (BD), and refrigerated freezer (BCD). Usually, most household refrigerators we see in the store are refrigerated freezer refrigerators—BCD.
1. Refrigerator refrigerator: store food that does not need to be frozen, the temperature range of the box is 0℃～10℃.
2. Freezer refrigerator: suitable for food freezing, the box temperature is below -18℃, used for freezing meat and fish.
3. Refrigeration and freezing refrigerator: suitable for frozen food and storage of frozen food. The temperature of the box is -18℃ or below. It has a freezer compartment and a star symbol is attached to the outer surface of the box to indicate the temperature characteristics of the refrigerator.