The compressor fridge

The compressor sucks the fumes from the evaporator and pressures them so that they get liquid in the refrigerator condensator part. The condensator grid (the grid your fridge has in its back part) emits the portion of the heat to the outer space of the room.

The cooling agnet - being pushed towards the sluice - expands and is driven to the evaporator again consuming all the temperature available in the limited refrigerator inner space (cooling it pretty down).

The absorption fridge

The absorption refrigerator uses the properties of some fluids (like water) to (first) catch the gasses around and (later) to loose them while consuming the temperature from the mixture and the space around.

The cooling agent is (usually) evaporated in the evaporator and it takes the warmth off the fridge inner space.

The vapors are condensed in the absorber part of the refrigerator, the temperature is exchanged with the environment and the cooling agent gets the form of the gass and is lead to the condensator where it liquefies again.

How to distinguish the compressor and the absorption refrigerator at the first glance (hearing)

Simply, the compressor fridge makes the noise, while the absorption one (the valve compressor doesn´t work) is quiet …