Depending on your heating and cooling needs, variable refrigerant flow (VRF) systems could be the right choice for your building. With benefits such as state-of-the-art controls, installation flexibility, quiet operation, and zoned and simultaneous heating and cooling, VRF technology provides a great alternative to traditional HVAC systems.
VRF systems were invented nearly 40 years ago but weren’t introduced in the United States until the 2000s. L.A. Lacy, however, didn’t see VRF systems enter the Central Virginia market until 2015. They won a renovation project at Albemarle High School that involved replacing the school’s traditional central air conditioning system with a VRF system.
The difference between the two is a conventional HVAC system mixes return air and outside air in a rooftop unit, which cools the air using water or refrigerant before sending it back to the space. Instead of one indoor unit and one outdoor unit, VRF systems feature one or more outdoor units, depending on the requirements of the building, that connect to multiple indoor units throughout the building.
VRF systems have a higher upfront cost compared to conventional HVAC, but they also have the potential to deliver long-term savings. Because VRF systems send the exact amount of refrigerant to meet the temperature requirement for a space, run time is minimized, saving energy and money. In some cases, owners have saved more than 30 percent of energy costs over forced air systems.
“You have a little more flexibility when you use a VRF system,” Senior Project Manager James Harrison explained. “If you set your thermostat to 70 degrees with a traditional system, the compressor will ramp up, run full speed until it reaches that temperature, and then just cut off. With the VRF, if you have different areas calling for heating or cooling, the compressor will slowly increase or decrease to meet that temperature requirement.”
VRF systems also minimize the amount of required ductwork, creating additional cost savings. Traditionally, you would have one large unit on the roof and run duct throughout the building into every room and drop it off into ceiling diffusers. With a VRF system, indoor units are mounted above the ceiling with enough ductwork for that area, or a cassette unit is installed in the ceiling and acts as its own system.
“We installed cassettes at Albemarle High School,” Plumbing Superintendent Curtis Wright said. “They fit in your two-by two-ceiling tile grid, and the refrigerant pipe connects to it. So, the unit in that two-by-two space could be your heating and cooling for your room. If you have multiple offices, you may have two or three cassettes in a space, but they all would have individual controls.”
Once a VRF system is up and running, there aren’t many disadvantages from a user standpoint, but to ensure it operates probably throughout its lifetime, L.A. Lacy’s technicians receive specialized training from the system’s manufacturer. It’s typically a three-day course that covers the manual, software, and the do’s and don’ts of installation.
“You have to be precise when you install a VRF system because if there’s a problem to begin with, it’s a lot harder to track down,” James said. “They are a little distinct as to the lengths of the refrigerant pipe, how much refrigerant you use, how they are connected.”
L.A. Lacy’s techs receive support from the vendor and supplier during the install and start-up phases. After the launching period, a representative from the manufacturer takes over and will fix any bugs; however, none of the systems L.A. Lacy installed have experienced any issues.
L.A. Lacy has four VRF system installations under their belt, but James and Curtis agree that manufacturers are heavily promoting them and that more engineers are incorporating the systems into their designs.
“We started hearing about other companies using VRF systems around the same time we started using them,” Curtis explained. “Before everything pretty much ran – when it comes to a heating and cooling standpoint – with hydronics. Now, a lot more of these systems are prevalent.”
Published by Starr Anderson, Marketing Communications Specialist, Branch Group