What happens to the refrigerant in the evaporator coil?

In the evaporator coil, the refrigerant plays a critical role in the refrigeration process by absorbing heat from the environment. When the refrigerant flows through the evaporator, it is typically in a low-pressure liquid state. As it circulates through the coil, it absorbs heat from the surroundings—such as the air or water being cooled. This heat absorption causes the refrigerant to change phase from a liquid to a gas, which is known as evaporation.

This process is fundamental because it utilizes the principle of heat exchange: as the refrigerant absorbs heat, it effectively cools the space around it. This phase change is necessary for the refrigeration cycle to function efficiently, as it helps in transferring heat away from the area that needs to be cooled.

In contrast, the other choices describe processes that do not occur in the evaporator coil; they either involve different stages of the refrigeration cycle or do not accurately represent the function of the evaporator itself.