Refrigerator Cycles

1st stage is the evaporator. This removes heat from the inside of the fridge. Turns the liquid into a fas in the pipes. Isothermal process.

2nd stage is the compressor. This raises the temperature of the gas which also raises the temperature and boiling point. This is an adiabatic process where there is no heat transfer.

3rd stage is the condenser. It’s the opposite of the evaporator in the 1st stage. Gas turns into a liquid, process that releases heat. Heat can flow from inside the condenser to the surrounding air. Isothermal process as the temperature of the fridge stays constant.

4th stage is the expansion valve which throttles the liquid. Lowers the pressure, temperature and boiling point. Adiabatic process.