Variable Refrigerant Flow (VRF) systems are typically all-electric systems that use heat pumps to provide space heating and cooling to building spaces. They are capable of serving multiple zones in a building, each with different heating and cooling requirements. These systems have the ability to modulate the amount of refrigerant sent to each zone in accordance with conditioning requirements. In contrast, conventional HVAC systems deliver air or water and operate on a full-on or full-off schedule.
Compared with air-to-air heat pumps, VRF offers energy savings due to better part-load efficiencies, heat recovery, smaller zones, and reduced duct losses. Annual energy savings depend on climate zone. Using Energy Pro building modeling software, annual heating and cooling energy savings for a 25,000 square foot assisted-living building are estimated at 37 percent in Seattle, 36 percent in Portland, and 29 percent in Billings.