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What Transport Refrigeration Units Main Parts and Working Principle are?

Jun  21,2017

Part 1: The components of
transport refrigeration units

The main parts of transport refrigeration units are condenser, evaporator, compressor, wire, control panel and pipeline. And the details of the components of transport refrigeration units, as shown in the following illustration.

the components of transport refrigeration units

Notes: During the refrigeration cycles of the compressor, the process from expansion valve to compressor inlet is the low pressure of the system and from compressor outlet to the expansion valve is the high pressure of the system.

Part 2: The work principles of each parts in the transport refrigeration units

1. Reefer Units for Trucks Condenser

A device that cools gases into liquids and condense it. The condenser coils that Guchen Thermo reefer units for trucks and refrigeration units for vans equipped with are aluminum micro-channel parallel flow coils, which makes the cooling effect of the transport refrigeration units achieve the best.

the condenser of transport refrigeration units
PHOTO: Condenser Coil adotps
aluminum micro-channel parallel flow coil

2. Transport Refrigeration Units Evaporator

a device in the transport refrigeration units that allows a compressed cooling chemical, such as R134a, R404a, to evaporate from liquid to gas while absorbing heat in the process. Guchen Thermo reefer units for trucks have the characteristics of small size, light weight and high heat exchanging efficiency. Also Guchen Thermo evaporator coils use aluminum foil with internal ridge copper tube to improve heat exchanging efficiency which improved by 30%. Moreover, the coil added in heat exchanger which make the heat exchange efficiency increased by 20%. All of these ensure the cooling effect of the transport refrigeration units to the best.

the evaporator of transport refrigeration units
PHOTO: Evaporator coil adopts aluminum foil with internal ridge copper tube

3. Transport Refrigeration Units Compressor

a mechanical device that pumps the refrigerant gases produced in the evaporator and compressed the gases into the condenser. Guchen Thermo transport refrigeration units use QP compressor and electric compressor.

Currently, the transport refrigeration units that equipped with QP compressor are the following units:

QP13 Compressor: TR-200T Van Freezer Units

▲ QP15 Compressor: TR-300T Refrigeration Units for Vans

▲ QP16 Compressor: TR-300 Small Truck Refrigeration Units, TR-350 Reefer Units for Trucks, TR-450 Reefer Units for Trucks, TR-550 Transport Refrigeration Units, and TR-650 Transport Refrigeration Units

4. Expansion Valve: a valve used to control the flow of refrigerant and reduce the pressure by regulating flow. The expansion valve that Guchen Thermo transport refrigeration units suppliers apply is Danfoss’s valve.

the expansion valve in transport refrigeration units

5. Refrigerant: is a substance or mixture, usually a fluid, used in a heat pump and refrigeration cycle. So the substance was chosen to be refrigerant should have a good thermal property and satisfying physical and chemical property. And the selection and use of the refrigerant should consider the occasion, temperature requirement, the quantity of refrigerating and the type of refrigerator comprehensively.

In Guchen thermo transport refrigeration units, C-series chiller units use R134a refrigerant, which the temperature ranges from -5℃to +25℃. So these units are convenient to deliver fresh goods, like milk, drugs, flowers, fruits and vegetable.

While TR-series and TS-series refrigeration units use R404a refrigerant, which the lowest temperature can down to -30℃. So it is very suitable for transporting freeze and frozen goods, like ice cream and frozen meat.

6. Refrigeration Oils: is to ensure the long-term and safe operation of the compressor. It is used to lubricate all fiction surfaces of the compressor and reduce the parts’ wear, improve mechanical efficiency, reliability and durability. Also it plays a great role in cooling system cleaning and gas proof. And it can be used as hydraulic power oil in the compressor to regulate energy. So the main functions of refrigeration oils are lubricating, sealing, cooling and energy regulating four parts.

7. Auxiliary equipment: Mainly consist of oil separator, reservoir, filter driver, gas-liquid separator, sight glass

Oil separator: 
 installed between the compressor and condenser and its function is to separate the refrigeration oil in the refrigerant discharged from the compressor. Meanwhile, it needs to send the separated oil back to the compressor.

Reservoir is used to stock refrigerant. Generally it is installed below the condenser. In this way, can it supplement the oil immediately if there are some accidents in the refrigerating, like the change and leak of refrigerant in the cooling cycle.

Filter driver belongs to the purification device in the cooling system. And its function is to clean water and sewage to protect the system from ice jamming and blocking. Also the filter at the end of the compressor inhalation can wipe out the  mechanical impurities of the system and reduce the mechanical wear of cylinders.

filter driver in transport refrigeration units

Gas-liquid separator is to separate the refrigeration oil from liquid refrigerant in order to protect the compressor from hydraulic pressure.

Notes: Gravity Separation( in medium and large refrigeration units, the air-return pipelines are equipped with gas-liquid separator to separate the liquid refrigerant from refrigeration oil in the air-return system of the refrigeration units)

Sight glass is mainly used in compressor crankcase, pipeline for supplying refrigerant, reservoir to indicate the condition of supplying refrigeration and oil-returning in the refrigeration system.

sight glass in transport refrigeration units

Crankcase pressure regulator(suction pressure regulating valve) : CPR valve is to regulate the ambient temperature of the compressor so that it can protect the compressor from the high temperature and increase the compressor’ service life.

CPR valve in transport refrigeration units

Currently, the Guchen Thermo Transport refrigeration units with CPR valve are TR-110D DC Powered Small Van Refrigeration Units: 

Guchen Thermo, as the leading transport refrigeration units manufacturer and primary truck refrigeration units suppliers, promises to provide the best service with the sincere heart, the most preferential prices and professional team. So if you want to buy truck refrigeration unit or refrigeration units for vans, please contact us !


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