Constant temperature and humidity test room, cold and heat shock test chamber, rapid temperature change test chamber, linear temperature change test chamber can be used in large refrigeration systems, now interpret a group of 2*30HP power cascade water-cooled refrigeration system, which is a very typical cascade refrigeration system, such systems are often used in comprehensive environmental test system and environmental stress screening test refrigeration system. The simulated temperature is minus 70 ° C.

High temperature refrigeration system from the compressor exhaust outlet to the suction inlet of the compressor a total of 6 loops: the first loop pump high temperature and high pressure working medium steam return compressor suction suction back air heating loop;

1. Return air heating loop

After the oil and gas separator, the high temperature and high pressure working medium steam is returned to the compressor suction port through the manual stop valve and the remote bypass valve of the solenoid valve. The working medium of this primary flow is the high temperature and high pressure working medium vapor of the compressor exhaust outlet, which is used to improve the temperature (pressure) of the refrigeration system return air to meet the requirements of the compressor intake air temperature (pressure).

After the condenser, dryer filter and liquid flow mirror, there are five branches of the liquid working medium:

2. Return air cooling circuit

Return to the refrigeration circuit of the compressor suction port through the solenoid valve and the internally balanced expansion valve. The function of this circuit is to reduce the temperature (pressure) of the return air of the refrigeration system. The first loop and the second loop work together to ensure that the temperature (pressure) of the suction port of the high temperature compressor is in a better working condition.

3. Evaporative condenser refrigeration main circuit

Through the solenoid valve, external balanced expansion valve, distributor into the evaporative condenser refrigeration main circuit. This is the main circuit of high temperature refrigeration. The liquid working medium evaporates into gaseous working medium in the evaporating condenser and absorbs a large amount of gasification latent heat (refrigeration). The high temperature and high pressure working medium steam discharged from the low temperature stage is cooled into liquid working medium in the evaporating condenser.

4. Evaporative condenser refrigeration auxiliary circuit

Through the solenoid valve, expansion valve into the evaporator condenser auxiliary refrigeration circuit. When the evaporative condenser does not need too much liquid refrigerant, close the solenoid valve, open the solenoid valve, only part of the liquid working fluid through the solenoid valve, external balance expansion valve, distributor into the evaporative condenser work, excess liquid working fluid will return to the gas pipe through other circuits;

5. Dehumidification circuit

Through the solenoid valve orifice restrictor distributor flows to the dehumidification cooling loop of the dehumidification ring and the pressure regulating valve, which is used for refrigeration dehumidification loop;

6. Environmental cold loop

Through the solenoid valve, expansion valve, distributor into the environmental cold ring, pressure regulating valve refrigeration circuit, this way is used for humidity and heat test temperature regulation circuit.