The fridge has four main components – the inside space where stuff needs to be cooled, the coolant, the radiator and the motor.
The coolant is where most of the action takes places. The coolant starts off as a liquid, absorbs heat from the inside space of the fridge and turns into a gas. The gas then travels to the radiator at the back via the motor. The motor compresses the gas, turning it back into a liquid causing the coolant to give off heat which is transferred to the environment by the radiator. The coolant liquid then starts the cycle again.