A Vapour Compression system is the most commonplace refrigeration cycle.

The refrigeration process is simply a cycle where a substance is picks up (absorbs) heat energy from one part of the cycle and gets rid of that heat energy in another part.

1. Step 1: COMPRESSOR
   Beginning at the compressor, the refrigerant is compressed and leaves the compressor as a high-temperature, high-pressure gas. This is the part of the system that works hard and uses energy (Electricity/or Pedal-Power!)
2. Step 2: CONDENSER
   The hot refrigerant enters the condenser, which is usually cooled by air blowing over it from a fan, and then the refrigerant leaves the condenser as a warm liquid and continues on to the thermal expansion valve. This is where Heat is pushed out of the system, turning refrigerant gas to a liquid.
3. Step 3: EXPANSION
   The expansion valve meters the proper amount of refrigerant into the evaporator. Expanding makes the pressure become very low very quickly, making it cold.
4. Step 4: EVAPORATOR
   There is a sudden pressure drop after the expansion valve converts the high-pressure warm liquid refrigerant into a low-pressure cold gas. The cold gas absorbs ambient heat from fan-forced air passing through the evaporator. This ambient heat converts the refrigerant into a cool, dry gas. From here the refrigerant re-enters the compressor to be pressurized again, and the cycle repeats itself. The cold refrigerant absorbs heat and evaporates into a gas, then makes its way back to the COMPRESSOR.

Through the refrigeration cycle, the colder side absorbs heat from its warmer surroundings and the hotter side rejects heat to its cooler surroundings.