BASIC PRINCIPLES OF REFRIGERATION

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Heat is energy.

Cold is a low energy state.

     Hot is a high energy state.

Heat causes a substance to expand.

     Cold causes a substance to contract.

BASIC MARINE REFRIGERATION
PRINCIPLES

Heat always transfer from a hot source to a cold source.

Cold is an absence of heat.

To reduce the temperature of a substance you extract heat from it.

The refrigeration system extracts and transfers heat from one source to another.

BASIC MARINE REFRIGERATION
PRINCIPLES

The refrigeration system is sealed. The refrigerant is the fluid that transfers the heat.  Unless there is a leak, the refrigerant charge remains constant.

The power source is electricity. The product is heat extraction.

     - Power In   =      1 kW

     - Heat Out   =   3.5 kW

What is Refrigeration?

Refrigeration can be described as a process that removes heat, cools down and maintains substances at a temperature lower than the surrounding ambient.

SOME USES OF REFRIGERATION ARE:

Food Storage

Food Transportation

Food Preparation

Food Production

Air Conditioning

Process Cooling

Chemical Production

Chemical Transportation

Some Terms & Definitions

Sensible heat:  Heat energy that causes a change in temperature   (joule)

 

Latent heat:    Heat energy that causes change in state at   constant temperature (joule)
 

Saturation Pressure:  The pressure at which a substance at any   given temperature can exist in equilibrium   with both its liquid and vapour states (bar)

Saturation Temp:  The temperature at which a substance reaches   its boiling point (ºC)

Superheat:   Any temperature increase above the saturation   temperature

Subcooling:  Any temperature below the saturation temperature

Saturation Temperature:

The temperature at which a substance reaches its boiling point (ºC)

Saturation Pressure in cylinders with different charge, stored in the same ambient temperature.

Saturation Pressure in cylinders with different charge, stored in different ambient temperatures.