All refrigeration involves the collection of heat in a suitable fluid, which is then withdrawn from the space material to be cooled, bringing the heat with it.
The fluid in question is known as refrigerant.
Primary and secondary refrigerants are two types of refrigerants that are used onboard.
Types of primary offshore reefer container refrigerants
This is the refrigerant used in the compressor, condenser, and evaporator systems, and it must meet particular specifications.
For example, at a low temperature and reasonable pressure, it will boil off or evaporate, and at a temperature around average seawater temperature and reasonable pressure, it will condense.
Wherever feasible, the refrigerant must be free of poisonous, explosive, flammable, and corrosive qualities.
Some refrigerants have a critical temperature below which they will not condense.
This was one of the drawbacks of carbon dioxide, which was widely utilised aboard ships for many years.
Ships operating in places with extremely hot seawater have trouble liquefying carbon dioxide without the aid of a sub-cooling system.
Another downside of carbon dioxide was the system’s extremely high pressure, which necessitated the use of huge and heavy gear.
Methyl chloride and ammonia were utilised as refrigerants between the carbon dioxide period and the current day.
Methyl chloride is currently prohibited for usage on ships due to its explosive qualities.
Ammonia is still used, but it needs to be ventilated properly.
With the exception of Refrigerant 502, which is an azeotropic (fixed boiling point) blend of Refrigerant 22 and Refrigerant 115, current refrigerants are fluorinated hydrocarbon compounds of different formulas.
These are commonly referred to as Treons, and they have a number associated with their formula.
Refrigerant 11 is a low-pressure refrigerant that requires a lot of circulation to cool effectively.
It has specific advantages when utilised in air conditioning equipment, as it consumes less energy.
One of the earliest fluorinated hydrocarbon refrigerants, as these numbered chemicals are known, to become widely available and inexpensively was refrigerant 12.
The fact that evaporator pressures are below atmospheric and that any system leaks pull in air and moisture is a disadvantage.
Refrigerant 22 is presently the most widely used refrigerant.
It can operate at low temperatures for a long time before the evaporator pressure drops below atmospheric levels.
The compressor displacement is roughly 60% less than that necessary for Refrigerant 12 and hence saves space.
The advantages of Refrigerant 502 include a displacement requirement that is similar to that of Refrigerant 22.
Because the compressor’s gas supply temperatures are lower, the lubricating oil is less prone to break down and the delivery valves are less likely to be stressed.
All of the refrigerants listed above are non-corrosive and may be used in hermetic and semi-hermetic compressors.
However, refrigerant 502 has less of an impact on the lacquers and elastomers used in compressors and motors.
Refrigerant 502 is still a pricey gas that isn’t widely available across the world.
A secondary refrigerant may be used in big air conditioning and freight cooling systems.
The primary refrigerant evaporator will be cycled with the secondary refrigerant in this situation, and the secondary refrigerant will subsequently be transferred to the space to be cooled.
Secondary refrigerants are used in big and sophisticated installations to avoid circulating expensive main refrigerants in enormous amounts.
Because these principal refrigerants may be highly searching, escaping via minute clearances, it’s critical to reduce the number of potential leakage sites to a minimum.
Where are refrigerants used?
The refrigerant is used in compressors, condensers, and evaporators.
In conclusion, we have discussed the types of refrigerants which consist of primary and secondary refrigerants respectively.
We also lightly touched on where are refrigerants are used.
A graduate (Business) from KDU, Jason Tan, is the current Business Director (Sales) for MGS Icestorm and has been associated with the company for the past 10 years.
With over 13 years in the shipping industry, he has had a significant contribution to Malaysia’s oil and gas industry in the engine and boat supply sector.
His expertise includes managing offshore catering business, offshore reefer containers, AI technology, offshore gas tanks, A60 pressurized cabins, etc. His contributions have helped establish MGS, in partnership (joint venture) with Thermo King and Honeywell to produce state of art Offshore Reefer Container products.