What is the purpose of the evaporator coil?

The purpose of the evaporator coil is to absorb heat from indoor air, making option B the correct answer. This component is crucial in the refrigeration cycle, where it functions by allowing the refrigerant to evaporate as it absorbs heat. As warm air from the indoor space is blown across the evaporator coil, the refrigerant inside the coil evaporates, extracting heat and cooling the air in the process. This results in lowered indoor temperature, contributing to the overall cooling effect in air conditioning systems.

In contrast, other options do not align with the role of the evaporator coil. Condensing refrigerant is the function of the condenser coil, while compressing refrigerant occurs in the compressor. Regulating airflow primarily involves fans or ductwork, rather than the coil itself. Understanding the specific function of each component in an HVAC system is essential for grasping how these systems work collectively to maintain comfortable indoor climates.