What happens to the refrigerant in the evaporator?

In the evaporator, the primary function of the refrigerant is to absorb heat from the environment and undergo a change from a liquid to a vapor. This process is crucial for the air conditioning and refrigeration systems to effectively remove heat from the spaces that need to be cooled.

As the refrigerant enters the evaporator coil, it is typically in a low-pressure liquid state. When it absorbs heat from the surrounding air or surface, it gains enough energy to change its state from a liquid to a vapor. This phase change is what enables the system to cool the air. The absorption of heat lowers the temperature of the surrounding area, providing the desired cooling effect.

The other choices imply different processes that do not occur in the evaporator. Condensation occurs in the condenser, expansion refers to the refrigerant’s pressure dropping through the expansion valve, and simply cooling down does not accurately describe the phase change that is central to the evaporator’s operation. Overall, the proper functioning of the evaporator hinges on the absorption of heat, leading to the evaporation of the refrigerant.