Air-to-Air Variable Refrigerant Flow Systems

Air-to-air variable refrigerant flow, or VRF, is a promising technology that could be used widely in commercial construction in the United States. This system is extremely flexible and can serve an unlimited number of zones in a building should piping lengths permit. In proper applications, the efficiencies of these systems are much higher than conventional systems used by many designers today. Understanding when to select a VRF system for a building is paramount to realizing the full potential of the system. A misapplied system, no matter how well designed, will not be able to perform at its full capability. After a designer has ensured that VRF is the correct system for a building, design can begin. Throughout the design process, the designer should refer to manufacturer data for unit capacities, allowable pipe lengths, pipe diameters, and DDC control information. Once design is completed, the installation of the system can proceed. Installation of the system is relatively easy, but contractors must familiarize themselves with the specific installation requirements of each manufacturer. All factors considered, VRF will likely gain popularity as designers learn more about the system.