What is the definition of a VRF air conditioning system? VRF air conditioning, otherwise known as Variable Refrigerant Flow, is a type of air conditioning system that uses refrigerant as its cooling and heating medium. This system is designed to provide a high level of comfort and energy efficiency, as it allows for the individual control of multiple indoor units. Each individual unit can have its own temperature setting, meaning that the temperature can be customized to the needs of the user. The system works by passing a refrigerant through an outdoor unit that has multiple compressors. The refrigerant is then circulated through the indoor units, allowing for control of the temperature in each room. The system is also designed to work more efficiently than typical air conditioning systems, as it maximizes the use of the refrigerant and minimizes energy consumption. VRF air conditioning is becoming increasingly popular as a way to provide energy efficient cooling and heating in a variety of settings.