The Fundamentals of (VRF) Variable Refrigerant Flow System

The Fundamentals of (VRF) Variable Refrigerant Flow System

Last Updated on March 19, 2023 by

Do you want to know if the VRF system is the right option for your heating and cooling requirements? Here, you will understand the basics of the VRF system.

It is used as a multi-split systems’ improved version; it features simultaneous heat-recovery cooling and heating capabilities.

Its system operation

The VFR systems offer several significant advantages, such as specific temperature control, zoning, and reduced ductwork, without needing secondary fluids, hot water distribution, or chilled water and its related costs. This fully electric technology has a separate outside condensing unit and several serving indoor units for multiple zones. It also has branch selectors of refrigerant piping and related controls.

It uses a refrigerant R-410A as a working and heat-transfer fluid reaching high EER that ranges from 15 to 20 and has 17 to 25 IEER. It is up to 30 percent extra efficient than traditional HVAC systems because of its incomplete load operation, zoning abilities, speed modulation, and heat-recovery design.

In comparison to traditional ducted systems that circulate air or chilled water throughout the facility, VRF systems are nontraditional HVAC systems. The term variable refrigerant flow (VRF) refers to a system’s ability to vary and manage refrigerant flow within the numerous evaporator coils and give proper temperature control in multiple mechanical support zones.

VRF systems transport heat of the room straight to evaporator coils placed within the adapted space utilizing direct expansion as a component of the primary refrigeration cycle. The heat-transfer medium, in this instance, is this refrigerant, which provides cooling and heating to multiple zones while using less energy than water or air.

VRF systems operate as a multi-split system, utilizes advanced indoor units to a single assembly of centralized outdoor condensing units, supplying simultaneous cooling and heating as well as thermal management in multiple zones as listed below:

  • At a predetermined time, the heat pump of the VRF system generates heating to indoor units and cooling.
  • At any time, VRF gives non simultaneous heating and cooling.
  • The heat recovery system offers simultaneous heat recovery, cooling, and heating, then transporting energy through heating zones from the cooling zones of the facility.

Above mentioned features are only possible because of VRF’s improved technology.

  • The capacity modulated and its variable speed.
  • The outdoor blowers with changeable frequency drive engines
  • The indoor units ECM or the electronically commutated motors

Its system types

Air-cooled and water-cooled are VRF systems, two various types.

  • Multiple compressors are linked into the refrigerant-piping loop in an air-cooled system. Therefore, in locations with high environmental temperature increases above 95°F—special consideration should be given to equipment selection.
  • Water-cooled, in which various compressors are linked to its water-source loop, enables heat recovery among compressor units.

Piping loop system

  • Two-pipe systems are typically used in VRF heat pump utilization to accommodate heating or cooling, particularly throughout the same working mode.
  • Three-pipe systems are structured with a return pipe, a cooling pipe, and a heating pipe. Plus, branch selectors are applied with three-pipe operations to achieve the same purposes as two-pipe systems except for separators.


A Variable Refrigerant Flow (VRF) system is a type of HVAC (Heating, Ventilation, and Air Conditioning) system that is gaining popularity due to its flexibility, energy efficiency, and precise temperature control. VRF systems are typically used in commercial buildings, such as offices, hotels, and hospitals, as well as in residential settings.

The VRF system uses a single outdoor unit that connects to multiple indoor units, which can be located in different rooms or zones. Each indoor unit can be controlled independently, allowing for customized temperature settings in each zone, which can help save energy and increase comfort.

One unique aspect of the VRF system is its use of a variable-speed compressor. This allows the system to adjust the amount of refrigerant flowing through the system based on the demand for heating or cooling in each zone. As a result, the system can operate at a lower capacity during times of low demand, which helps reduce energy consumption and lower operating costs.

Another key feature of the VRF system is its ability to heat and cool different zones simultaneously, particularly useful in buildings with varying occupancy levels or where different zones require different temperature settings.


VRF is determined to be more practical than traditional HVAC. These systems are very simple to install and operate, do not require dedicated maintenance areas and utility shafts, and free up functional building space that you will find beneficial.

Read more: Industrial Process Piping Systems – Expert Design for Complex Fluid Management.