Marine Refrigeration System: Vapour Compression Cycle


Refrigeration system that works on Vapour Compression Cycle has following basic components

  1. Compressor
  2. Condenser
  3. Expansion Valve
  4. Evaporator
  5. Refrigerant Fluid

We know that the saturation temperature (the temperature at which fluid boils or condenses) of a fluid varies with the pressure.

The compressor raises the pressure of vaporized refrigerant which in turn increases the saturation temperature. It also helps the refrigerant pump around the system. Now the refrigerant is in the state of Super Heat with High-Pressure vapor with high temperature (90 °C with 11.92 bar) goes to the condenser.

In the condenser, The refrigerant is sub-cooled, by circulating seawater (or air), to a temperature below its saturation temperature. In this, the refrigerant liberates heat to the seawater and vapor will get condensed to liquid with a decrease in the temperature. Now the refrigerant is in the state of Subcooled liquid i.e Low temperature and High pressure (25 °C with 11.92 bar) and goes to the expansion valve.

The expansion valve is the throttling device through which refrigerant flows from the high-pressure side to the low-pressure side. Due to pressure drop boiling point of the refrigerant comes down and it starts evaporating. The latent heat comes from itself and its temperature drops. ( to about -35 °C and 1.2 bar)

The refrigerant then enters the evaporator coil, where the cooling phenomenon takes place ( Eg. Fish room, meat room, etc). This refrigerant has a temperature lower than that of the surrounding temperature.

This cycle is know as Vapor Compression cycle and is repeated again and again.

floe diagram of a simplefied vapour compression system using R22 refrigerant
floe diagram of a simplified vapour compression system using R22 refrigerant

Vapour Compression System
Vapour Compression System


  1. Good day
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