文档介绍：Computer Modeling VRF Heat Pumps in
Commercial Buildings using EnergyPlus
Richard Raustad
ABSTRACT
Variable Refrigerant Flow (VRF) heat pumps are increasingly used in commercial buildings in the United States. Monitored energy use of field
installations have shown, in some cases, savings exceeding 30% compared to conventional heating, ventilating, and air-conditioning (HVAC)
systems. A simulation study was conducted to identify the installation or operational characteristics that lead to energy savings for VRF systems.
The study used the Department of Energy EnergyPlus™ building simulation software and four reference building models. Computer simulations
were performed in eight . climate zones. The baseline reference HVAC system incorporated packaged single-zone direct-expansion cooling
with gas heating (PSZ-AC) or variable-air-volume systems (VAV with reheat). An alternate baseline HVAC system using a heat pump
(PSZ-HP) was included for some buildings to directly compare gas and electric heating results. These baseline systems were compared to a VRF
heat pump model to identify differences in energy use.
VRF systems combine multiple indoor units with one or more outdoor unit(s). These systems move refrigerant between the outdoor and indoor
units which eliminates the need for duct work in most cases. Since many applications install duct