VRF Outdoor Unit

AirConditioner:VariableRefrigerantFlow

Used in:   VRF Loop

This model simulates a variable-refrigerant-flow (or variable-refrigerant-volume) air-conditioning system. This system type models direct-expansion cooling and/or heating coils configured in a zone indoor unit.

There are two common types of variable refrigerant flow (VRF) heat pump systems:

• Cooling only or heating only air-conditioning systems (a.k.a. heat pump), or
• Heat recovery systems that allow simultaneous cooling and heating

The VRF outdoor unit supports air-, evaporatively-, or water-cooled condenser equipment. Throughout this section, the term “condenser” refers to the outdoor unit where the compressor is located.

Enter data on one of the 4 tabs:

• General
• Cooling
• Heating
• Heat Recovery

The screenshot below shows a typical VRF layout diagram with outdoor and indoor units linked.

VRF Resources

You can learn more about practical aspects of VRF design and simulation for project work (in the context of GSHP systems) by watching our webinar: Design and Modelling of Ground Source Heat Pump Systems

• DesignBuilder curve generation spreadsheets can be downloaded from the software downloads area of the website.

• The EnergyPlus Engineering Guide includes a Detailed technical description of the way the VRF model works.
• Richard Raustad of Florida Solar Energy Center report on Creating Performance Curves for Variable Refrigerant Flow Heat Pumps in EnergyPlus
• VRF System Design and Simulation Webinar presented by DesignBuilder, Mitsubishi and Building Performance Team, recorded on 01.09.15.