Can any experts talk about the principle of refrigeration system?

Water-cooled and air-cooled can be divided into single cooling type and refrigeration heating type according to the purpose of use. No matter what type of structure, it is composed of the following main components.

1. The main components of the refrigeration system are compressor, condenser, evaporator, expansion valve (or capillary tube, supercooling control valve), four-way valve, compound valve, one-way valve, solenoid valve, pressure switch, safety plug, output pressure regulating valve, pressure controller, liquid storage tank, heat exchanger, heat collector, filter, dryer, automatic switch, stop valve, liquid injection plug, etc.

2. The main components of the electrical system are motors (used for compressors, fans, etc.). ), operating switch, electromagnetic contactor, interlocking relay, overcurrent relay, thermal overcurrent relay, temperature regulator, humidity regulator, temperature switch (used for defrosting, antifreeze, etc. ). Compressor crankcase heater, water cut-off relay, computer board and other components.

3. The control system consists of several control devices, which are:

Refrigerant controller: expansion valve, capillary tube, etc.

Refrigerant loop controller: four-way valve, one-way valve, compound valve and solenoid valve.

Refrigerant pressure controller: pressure switch, output pressure regulating valve and pressure controller.

Motor protectors: overcurrent relay, thermal overcurrent relay and temperature relay. Temperature regulator:

Temperature position regulator, temperature proportional regulator. Humidity regulator: humidity position regulator.

Defrosting controller: defrosting temperature switch, defrosting time relay and various temperature switches.

Cooling water control: water cut-off relay, water regulating valve, water pump, etc.

Alarm control: over-temperature alarm, over-humidity alarm, under-voltage alarm, fire alarm, smoke alarm, etc.

Other controls: indoor fan speed controller, outdoor fan speed controller, etc.

2.3 Commonly used refrigerants and their characteristics

There are many kinds of refrigerants. Freon 12 and 22:

A freon 12(CF2Cl2) code R 12 freon 12 is a colorless, odorless, transparent and almost nontoxic refrigerant, but when the air content exceeds 80%, it will cause suffocation. Freon 12 will not burn or explode. Hydrogen fluoride, hydrogen chloride and phosgene (CoCl2 _ 2) harmful to human body can be decomposed when exposed to naked flame or when the temperature reaches above 400℃. R 12 is a widely used medium-temperature refrigerant, which is suitable for small and medium-sized refrigeration systems, such as refrigerators and freezers. R 12 can dissolve a variety of organic substances, so ordinary rubber gaskets (rings) cannot be used, and chloroprene rubber or nitrile rubber sheets or sealing rings are generally used.

B Freon 22(CHF2Cl) code R22 R22 is nonflammable and non-explosive, and its toxicity is slightly higher than that of R 12. Although the solubility of water is greater than R 12, it may still cause "ice jam" in the refrigeration system. R22 can be partially dissolved with lubricating oil, and its solubility varies with the type and temperature of lubricating oil, so the refrigeration system using R22 must have oil return measures.

The evaporation temperature of R22 at standard atmospheric pressure is -40.8℃, the condensation pressure at room temperature is not more than 15.68× 105 Pa, and the refrigerating capacity per unit volume is more than 60% higher than that of R 12. R22 refrigerant is mainly used in air conditioning equipment.