Montgomery, Alabama, has seen savings of up to 42 percent after implementing VRF technology.
The City of Montgomery, Alabama, has significantly reduced the utility bills of its public utilities by installing variable refrigerant flow (VRF) technology.
And the savings are just the beginning.
VRF, an HVAC technology dating back to 1982, uses refrigerant as a cooling and heating medium. It is conditioned by one or more condensing units and circulated to multiple indoor units within a facility. Unlike conventional chiller-based systems, VRF allows varying degrees of cooling in specific areas. This is because large air handling units are replaced by smaller indoor units.
Montgomery, with a population of 240,000, has 326 conditioned airspace facilities. They range in size from community centers of 1,800 square meters to an office complex of 72,000 square meters. The oldest dates from 1897.
Doug Jones, Montgomery’s director of building maintenance, began studying VRF a decade ago for the most practical reasons.
“For anyone involved in major property maintenance, one of their biggest concerns has to be utility bills – they do nothing but go up every year. Ours got deadly out of control.”
It was then that Jones convinced the city’s fire chief to allow him to convert a single fire station from a standard two-pipe boiler/chiller setup with condensing units to a VRF system. The result was impressive: the energy bill fell by 36 percent.
Jones, in his current role for 13 years, is a 26-year veteran of facilities management and oversees 75 employees. He was previously deputy director of street maintenance and construction and has worked for the city for over 39 years.
Savings of 24 to 42 percent
Montgomery currently has VRF systems installed in 18 of its buildings. They include City Hall, at 44,000 square feet; a downtown government office at 25 Washington Ave. of 72,000 square feet; and six of the city’s 16 fire stations.
(The 44,000-square-foot City Hall is one of Montgomery’s 18 buildings to benefit from cost savings with VRF technology.)
VRF, as the name suggests, is a variable speed system.
“Unlike the HVAC in your house or a standard HVAC, where if you turn on the thermostat, it opens wide, VRF only ramps up where it should,” Jones says. “If you have a reasonably cool or warm space that you’re trying to cool, it won’t come up to full power. It will increase to exactly what it needs to condition that space.”
The process works: at several locations, the energy bill has been reduced from 24 percent to 42 percent. That said, it’s not cheap: Installations in the six-story building at 25 Washington cost $94,000 per floor. The building, built in 1897, includes office and meeting space and a restaurant, was renovated in 1981 and recently converted into a VRF.
The project at Union Station, which was completed in July, took nine months but is atypical, Jones said.
“That building is 44,000 square feet and was built in 1897, so we went through 18-inch thick brick walls.”
However, the home team’s locker room at Riverwalk Stadium, which was converted into VRF two years ago, only lasted two months.
To date, the installations Jones and his team completed have saved the city nearly $1 million a year. He estimates that if the city can add VRF to all its buildings, it can achieve a 30 to 35 percent reduction in energy costs.
The city’s VRF system uses products from a trio of manufacturers, including Fujitsu Limited.
Return on investment has been solid, he says.
“When we installed the units in Washington 25, the electric bill there was $22,000 a month. We cut it down to $7,000 a month and paid for the equipment in 31 months. Since then, we’ve continued to show energy bill savings. .”
The hardest part of installing the VRF systems, Jones says, is “retro” them to a renovated facility.
“Because of the copper piping and the way things are done, that’s the most challenging thing about it. If you incorporate it in a new building, there is really no challenge.”
Go to the next level
In some cases, workarounds have proved more than a little challenging.
“Fire stations are, of course, open 24 hours a day, seven days a week, and so the temporary solutions are very, very challenging,” Jones says.
Much of it is planned, and the rest “is a matter of going in and mapping out where your equipment is going and running all the necessary copper pipes.”
With 24 hour operations, it is of course paramount to find ways to minimize downtime.
“At some point you have to shut down the old system to install the new system,” Jones says, “so that’s your main solution, figuring out when this building can actually be without any mechanics for a two- or three-day period.”
So far, Jones says, there have been no bugs in the VRF systems. In fact, he’s already started taking them to the next level. In three facilities – Riverwalk Stadium, the main public library and Union Station – his team has installed a smart system that allows him to monitor and control them all from his office.
“I can actually sit here at my desk and pull up the whole system with each of these buildings,” he says. “If I get a call and someone says, ‘We’re hotter, this device isn’t working right,’ I can turn around to my computer and with three clicks I can be in the system and see exactly how the systems are running. I can exactly see what the room temperatures and pressures on the units are.”
Why would a facility manager, with all the associated benefits, decide not to go for VRF?
“The argument against this is that it’s new technology and some people are afraid of new technology,” Jones says.
It can be “a scary proposition” not only for managers, but also for the employees.
“I have nine HVAC technicians who work for me, and I can tell you that ten years ago, seven of them were terrified of this stuff,” he says. “Today I can put one of my HVAC technicians on a VRF system and they can install or repair it.”
The necessary training, including continuing education, has been provided by one of the manufacturers and has proven effective.
“My HVAC technicians have their own laptops and trucks. They can walk into these facilities, plug in and diagnose an entire system while standing on a controller on their laptop in one place,” Jones says.
The goal is to eventually set up every facility in Montgomery with VRF, but that will take time. Five years ago, Jones predicted it would be a 15-year project, but it’s going to take longer than originally planned.
“Obviously the only problem with that is that we’re government, so if the economy is fluctuating in some way, revenues go up, revenues go down. We’re probably over 15 years away from all our facilities moving to a VRF.” system,” he says.
Jones admits that “his hindsight is always 20/20,” Jones thinks the only thing he would have done differently was to have his entire staff of mechanics trained from scratch.
“I started with four of my nine mechanics on it, and that got a bit of a hassle if there was a diagnostic problem because now you have to move crews,” he says. “I think knowing what I know now, I would have pre-certified all my HVAC technicians.”
Jones’ advice to colleagues across the country is twofold: Do your research beforehand and put aside the initial trepidation.
“We were actually one of the first in the Montgomery area to install these systems. In fact, here in Montgomery we have two of the three largest systems in the United States. The most important thing I can tell you is that you should do your research – and not be afraid of the technology.”
Howard Riell is a freelance writer based in Henderson, Nevada.