Variable refrigerant flow (VRF) is an HVAC technology introduced in Japan more than 30 years ago. It was invented to minimize the losses found in conventional HVAC systems and to reduce the footprint of these systems. Think of the VRF as a big ductless split with multiple indoor heads—a VRF system can have up to 60 indoor units connected to a single outdoor unit.
How does it work? Like ductless mini-splits, VRFs use refrigerant as the cooling and heating method. Conditioned by a single outdoor condensing unit, the refrigerant is circulated throughout the building to multiple fan-coil units (FCUs). Usually, you install a VRF system with an air conditioner inverter that adds a DC inverter to the compressor to support variable motor speed and to generate variable refrigerant flow.
As it operates at varying speeds, variable speed fans for both outdoor and indoor units, with electronic expansion valves opening and closing in every indoor unit to match the capacity, the refrigerant flow is modulated depending on the load, resulting in substantial energy savings.
The VRF system comes in two types of units: Heat Pump and Heat Recovery. With the Heat Pump unit you can only have all cooling or all heating—cooling the inside in the summer and heating the inside in the winter. With the Heat Recovery unit, you can simultaneously heat certain zones while cooling other zones. When you extract heat from a zone that requires cooling, you can divert it to the zone that requires heating. Although the Heat Recovery unit is more expensive, in the long term it delivers overall greater efficiencies.
The benefits of a VRF system are many:
- With heat recovery between areas, the heat rejected from one area can be used in another part of your building rather than being rejected to the outside and wasted, cutting costs and energy use.
- You have minimal losses from ducts since nearly all of the ductwork is eliminated. When you eliminate ductwork, you can design buildings with lower floor-to-floor heights, reducing your construction costs.
- You can install a VRF system in smaller indoor and outdoor spaces as they require less piping and duct space. Usually, the VRF includes two refrigerant pipes with a non-polar, two-wire control connection that equate to faster installations with fewer installers.
- As a VRF system rapidly adapts to changing loads and controls temperature through precise load matching, it ensures efficient operation and superior dehumidification.
- You enjoy lower life-cycle costs as VRF systems have fewer components than other HVAC systems; thus, you reduce your initial equipment and installation costs as well as your future maintenance costs.
- If you have a commercial building the potential for savings is huge as your occupants can choose to either cool or heat only the space they use—delivering comfort on demand.
- With the VRF system, you reduce sound levels as the inverter compressor ramps up and down smoothly so your occupants can work without distraction, and sleep without noise.
- The VRF system is flexible as you have a choice of multiple types and sizes of fan coils that fit any application. You have more and better design options than other HVAC systems.
- The VRF system is designed for sustainable green buildings and can gain you points toward LEED® certification, depending on how much you can reduce your project’s predicted energy costs.
When you can choose HVAC technology that delivers customizable comfort control to buildings with many floors and areas simply by moving refrigerant to the zone you want heated or cooled, why would you choose any other system? Especially when the system delivers significant benefits to the contractor, to the building’s occupants, and to the environment.
A VRF system provides exceptional comfort, maximum control, and energy efficiency—it is an effective and efficient solution for all your heating and cooling requirements.