Variable refrigerant flow (VRF) HVAC systems may soon become a very important import in the U.S. It has about 24% of the global commercial air conditioning market and over 35% market share in China, India, the European Union, and Eastern Europe. But as of 2012 in the U.S., VRF represents only 3%, according to a GSA report citing manufacturer LG.
About one-third of commercial building energy usage in the U.S. is used for heating, cooling, and ventilation, according to the GSA. Owners and FMs would be wise to consider any technology that can slash that piece of the pie.
While VRF has been dominant worldwide for over 20 years, the U.S. has been slow to accept it for several reasons. Products have primarily been manufactured by Asian companies, which at one point had limited presence in the U.S. There is also little critical evaluation of actual field energy performance.
But VRF sales in the U.S. are growing and multiple manufacturers offer these systems, including Carrier, Daikin, LG, Mitsubishi, and Sanyo.
If you still have questions about how it works, what motivates its implementation, and where its potential is maximized, let the following guide help you with your next HVAC decision. VRF is valuable for either whole buildings or individual spaces and floors.
VRF systems are comprised of two major parts: a compressor unit and multiple indoor fan coil units. The compressor, typically located on the roof, cools and heats refrigerant connected through piping to the building.
These systems are capable of simultaneously cooling some zones and heating others. They can recover heat from spaces being cooled for use in spaces being heated and vice versa.
“Energy consumption is cut by offering on-demand cooling and heating for individual zones. Power reduced because the system operates only at the levels needed to maintain a constant, comfortable indoor environment,” explains Mike Smith, senior marketing manager for manufacturer Mitsubishi. “The condenser fan rarely has to run at full speed, offering quiet performance.”
The fan coil units can be mounted directly in the space or configured in the ceiling, walls, or at floor level. They also can be hidden above the ceiling or located near, but not in, the conditioned space.
Because of its zoning customization abilities, VRF systems offer integrated controls with the units, which typically don’t require a separate building automation system. Many also include self-diagnostics and monitoring points.
These features allow VRF systems to achieve 30% or higher HVAC energy cost savings relative to minimally code-compliant conventional systems, according to a report from Pacific Northwest National Laboratory (PNNL).