Final answer:
Variable Refrigerant Flow (VRF) systems modulate the volume of refrigerant using an electronic expansion valve (EEV) based on the cooling or heating demand in different zones or areas.
Step-by-step explanation:
Variable Refrigerant Flow (VRF) systems modulate the volume of refrigerant that is pumped through the system by using an electronic expansion valve (EEV). The EEV adjusts the amount of refrigerant flowing through the system based on the cooling or heating demand in different zones or areas. This modulation of the refrigerant volume allows for precise temperature control and energy efficiency.