How does an evaporator coil function in an AC system?

The evaporator coil plays a crucial role in an air conditioning system by absorbing heat from the indoor air. When warm air from the inside of a building passes over the evaporator coil, the refrigerant inside the coil, which is in a low-pressure, liquid state, evaporates as it absorbs this heat. This process cools the air, leading to a reduction in temperature throughout the space. As the refrigerant evaporates, it changes from a liquid to a gas, effectively removing heat from the indoor environment. This mechanism is fundamental to the cooling process of air conditioning systems, enabling them to maintain a comfortable indoor climate.

The other options presented do not accurately describe the function of the evaporator coil in an AC system. The coil does not pump refrigerant; that function is performed by the compressor. It also does not release moisture into the air, as its role is primarily to cool and dehumidify the air. Lastly, cooling outdoor air is managed by the condenser coil, not the evaporator coil.