refrigeration question

[vpbarkley]

My boat's fridge could be described as having two logical parts.
Part 1 includes the fridge box and evaporator.
Part 2 includes the compressor and condenser.

There is but a single copper line that connects Part 1 to Part 2.

The usual refrigeration cycle requires two lines to form a circuit.

Unless the tube is coaxial, I don't understand how the system works.

If you do know how this system works, please enlighten me.

The fridge is a Vitrifriga 130 liter model with a Danforth compressor.

This is the OEM refrigerator included in a USA manufactured boat.

[racer1958]

There is a capillary small gauge tube inside of the low pressure return pipe.
You can see the capillary tube going inside of the return pipe close to the compressor.