In a simple refrigeration system, where does the refrigerant boil?

In a simple refrigeration system, the refrigerant boils in the evaporator. The evaporator is designed to allow the refrigerant to absorb heat from the surrounding environment, which causes it to change from a liquid state to a gas. This phase change is crucial because it is the fundamental process that removes heat from the area being cooled.

As the refrigerant enters the evaporator, it is at a low-pressure state. As it flows through the evaporator coils, it absorbs heat from the air or liquid in contact with the coils. This heat absorption raises the temperature of the refrigerant, causing it to boil and transition into a gaseous state. This process is what enables the refrigeration cycle to effectively remove heat from the environment, thereby cooling it.

The metering device, on the other hand, is responsible for controlling the flow of refrigerant into the evaporator but does not facilitate boiling; the compressor's primary role is to compress the gaseous refrigerant and not to boil it; while the condenser is where the refrigerant releases heat and condenses back into a liquid, occurring at pressures higher than in the evaporator. Therefore, the evaporator is the correct location for the boiling of refrigerant in a refrigeration system.