This is the eleventh article covering one of several energysaving technologies evaluated in a recent U.S. Department of Energy report. The complete report is at www.eren.doe.gov/buildings/documents.

Refrigerant systems that vary flow and volume (VRF/V) are basically large-capacity versions of ductless multisplit air-conditioning or heat pump systems. In contrast to conventional HVAC systems, they circulate refrigerant directly to multiple evaporator units, rather than using water (in chillers) or air (in ducted DX systems) to achieve heat transfer to the conditioned space.