At present, domestic refrigerators and air conditioner compressors are all positive displacement, which can be divided into reciprocating and rotary. The rotary type uses a rotating shaft crank mechanism. According to the application range, it can be divided into low back pressure type, medium back pressure type and high back pressure type. Low back pressure type (evaporation temperature -35 ~ -15 ℃), generally used in household refrigerators, food freezers, etc. Medium back pressure type (evaporation temperature -20 ~ 0 ℃), generally used in cold drinks cabinets, milk refrigerators, etc. High back pressure type (evaporation temperature -5 ~ 15 ℃), generally used in room air conditioners, dehumidifiers, heat pumps, etc. The reciprocating compressor uses a piston, crank, connecting rod mechanism or piston, crank, slide tube mechanism.
The specifications of the compressor are divided according to the input power. Generally, the difference between each specification is about 50W. In addition, there are also divided by cylinder volume. The main performance indicators of the compressor are: input, output power, coefficient of performance, cooling capacity, starting current, running current, rated voltage, frequency, cylinder volume, noise, etc. Measure the performance of a compressor, mainly from the comparison of three aspects of weight, efficiency and noise.
1. Composition of refrigerator compressor
Refrigerator air conditioner is composed of four major parts: compressor, condenser, expansion valve and evaporator, according to the control or use needs, you can choose to install pressure controller, temperature controller, drying filter and other auxiliary devices, but the four major parts It's a lot.
2. Liquid refrigeration
During operation, the gaseous refrigerant is compressed into high-temperature and high-pressure gas by the compressor, and then enters the condenser. The condenser is equivalent to a heat exchange device, which exchanges high-temperature and high-pressure gaseous refrigerant into low-temperature and high-pressure liquid refrigerant.
3. Throttling device
The liquid refrigerant passes through the expansion valve again. The so-called expansion valve is a throttling device. Since the refrigerant flowing out of the expansion valve is contained, the pressure of the refrigerant decreases and the temperature continues to drop after exiting. (The expansion valve of refrigerators is generally replaced by capillary tubes, because From the large tube to the small tube suddenly, it can also play the role of throttling) to become a gas-liquid two phase.
4. Heat exchange gasification
Then it enters the evaporator, and the refrigerant reheats and vaporizes in the evaporator at this time, and the high-temperature and low-pressure gas refrigerant returns to the compressor and continues to circulate.
