Looking For HVAC Zone Control?

To satisfy energy efficiency and occupant demands, variable refrigerant flow systems may deliver on facility management needs.

By Kevin Miskewicz
From the August 2018 Issue

VRF systems
(Photo: 123rf.com)

In recent years, Variable Refrigerant Flow (VRF) HVAC technology has steadily gained traction among facility management professionals who are attracted to the energy efficiency, installation flexibility, and temperature control capabilities that VRF offers. This technology has been increasingly applied in a broad array of applications, from health and wellness facilities and churches to schools and office spaces.

Despite its rise in popularity, there is still some mystique among when it comes to the ins and outs of a VRF system. To put it simply, these systems offer full-range variable capacity to deliver only the precise amount of conditioning needed to fulfill a zone’s demand.

Commercial buildings exhibit partial load conditions around 90% of the time. Without variable capacity compressors, traditional systems struggle to meet set point (temperature) satisfaction, which results in energy usage fluctuations. VRF systems work in tandem with integrated controls and sensors that measure load demands for individual cooling and heating zones. From there, the compressor adjusts its speed to maintain a desired temperature.

HVAC Zone Control
Mitsubishi Electric Trane HVAC US LLC

Facility managers can expect an array of benefits from installing VRF systems, whether in a retrofit or new construction. The most obvious and immediate benefit comes in the form of lower utility bills. VRF systems can increase energy efficiency by up to 25% over traditional HVAC systems. Much of this increase comes from the use of inverter compressor technology coupled with the minimal or eliminated ductwork requirements. Additionally, VRF systems offer design flexibility, due to a two-pipe system design, and can be used in applications where ductwork is not an option. Finally, VRF systems offer a high level of control that leads to personalized occupant comfort.

As mentioned above, this technology is not limited by application, climate, or building design. An array of facility types reaps the benefits of applying VRF systems.

For instance, the Bank of San Antonio in San Antonio, TX was searching for a way to address the different comfort and operational needs of defined spaces within its building, including conference rooms, offices, and an IT area. The building manager opted to use VRF technology to create zones, each with its own comfort controls. The system is able to meet the requirements of each zone, while minimizing energy usage overall.

The Johnson County Community College in Overland Park, KS recently opened a new academic building on campus. The school’s Center for Sustainability had set goals to promote an environmentally and socially responsible campus, and to become a 100% renewable energy campus by 2050. With sustainability at the forefront, they made the decision to use a VRF system to heat and cool the academic building’s three distinct spaces. Another selling point was the ability of the VRF system to simultaneously cool and heat while retaining its energy efficiency. Due partly to its application of VRF systems, the building achieved LEED Platinum Certification.

Another example is the 50,000 square foot mixed-use office space, nicknamed “The Move” in Castle Rock, CO. The four-story shared office space was built to accommodate the rapidly growing business population in this small town. Occupants had varying needs, but a common one was a productive and comfortable workspace. The quiet operation offered by a VRF system meant that tenants wouldn’t face distraction from a noisy HVAC system. VRF technology also addressed the need for zone control, to ensure all occupants had comfortable working environments year-round.

Finally, St. Patrick Catholic Church (Lake Forest, IL) was over 100 years old when it underwent structural renovations to accommodate a growing community. After many years without air conditioning, the church’s construction manager decided to make the space more comfortable for its growing congregation, and installed a new cooling and heating system. The local climate meant frigidly cold winters and hot, humid summers, so it was very important to find a system that was dependable for both extremes. The design team faced additional challenges, too. They needed an unobtrusive system for the historical place of worship, and one that was quiet enough to maintain the sacred, contemplative atmosphere.

VRF technology may still be gaining ground, but it is doing so at a rapid pace. Facility managers, building owners, and everyone in between are beginning to recognize the myriad benefits and economic value VRF systems offer the buildings they serve.

VRF systemsMiskewicz is director of commercial product planning for Mitsubishi Electric Trane HVAC US. He leads the marketing strategies, programs, and initiatives for the division’s commercial product line, and is a certified LEED® Green Associate.

Do you have a comment? Share your thoughts in the Comments section below or send an e-mail to the Editor at acosgrove@groupc.com.


  1. What is the minimum communicating opening area of the smallest space served by a VRV system that is considered safe in the event the entire refrigerant system charge leaks into that space?
    Also, what pipe insulation is required by code for the various refrigerant phases? Thank you.

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