Last year, the Department of Defense (DoD) issued a surprising directive stating that VRF systems would no longer be permitted in U.S. Air Force facilities, and while not forbidden in Army facilities, they would be strongly discouraged. However, the Navy does not plan to restrict VRF systems, as long as they comply with ASHRAE Standard 15, Safety Standard for Refrigeration Systems.
A subsequent U.S. Army Corps of Engineers Bulletin offered three reasons for the new directive:
- Concern over refrigerant concentration, as a typically sized VRF system contains enough refrigerant to potentially asphyxiate occupants in the event of a refrigerant leak;
- Difficulty in locating refrigerant leaks due to long refrigerant lines that are common with VRF systems; and
- Proprietary controls used by many VRF systems, which are in conflict with the legal requirement of using open protocol systems.
Last November, the DoD placed its own special requirements on VRF systems, citing the same “inherent risks” above, as well as adding its intent to study the technology’s life cycle costs — the reason being that VRF systems are relatively new within the U.S, which makes comparisons with traditional HVAC systems difficult. VRF manufacturers and the Air-Conditioning, Heating & Refrigeration Institute (AHRI) have since been engaged in an ongoing dialogue with the DoD to better understand its concerns and help explain the unique attributes of VRF systems.
John Reynal, president, Encore Mechanical LLC, Southlake, Texas, has installed numerous VRF systems in Army facilities, but he was not too surprised by the recent directive.
“Our series of VRF installations on Army bases occurred after several conventional four-pipe boiler/chiller-type installations experienced troubled warranty periods and IAQ issues. We installed VRF systems in 17 new Army buildings serving the same purpose, which cut construction duration nearly in half, reduced upfront cost by 40 percent, and eliminated the warranty and IAQ problems through good design and installation.”
Reynal believes the DoD and the Corps of Engineers might have formed their negative opinions regarding VRF systems due to the technology being improperly installed by unqualified firms, which may have been a result of a procurement process that did not adjust for the new technology.
“Another reason may be the standard resistance to change, and/or because VRF is disruptive and threatens experts and businesses that specialize in older technologies.”
Scott McGinnis agreed with that last point. As branch manager of Direct Expansion Solutions (DXS), which is a representative for Daikin VRF systems in Dallas/Fort Worth, Texas, he believes there has been a concerted effort by some in the HVAC industry to discredit VRF as a viable option for many applications.
“It pays to discredit the competition, especially when that competition is gaining market share,” he said.
That may be the case, or it may just be that the Corps has a difficult time managing all the technology options that are now available for the armed services, said Andy Armstrong, vice president of sales and marketing, Fujitsu General America Inc.
“To achieve their goals requires input from many sources,” he said. “In this case, it seems that the input was a bit off target. But VRF solutions in many applications needed by the armed services are not only the best option for comfort, they are also the most efficient.”
And efficiency is extremely important, given that both former Presidents George W. Bush and Barack Obama issued executive orders that require federal agencies to reduce electrical consumptions by 25 percent over a 10-year span, said Reynal.
“VRF technology provides a way to achieve that mandate without the need for other upfront costs and maintenance required by other design choices that can require natural gas service to the building, or ground water well fields, or water chemical treatments,” he said.
The question for many at this point is whether or not the Corps’ concerns over VRF systems are valid. Reynal would argue yes and no, adding that their concerns should hold true for any and all HVAC design choices, particularly when the procurement process does not properly qualify designers and/or installing contractors.
“Conventional system choices are based on 60-year-old technologies and are also susceptible to troublesome installations when untrained/unqualified technicians attempt to install them,” he said. “VRF is a much newer and more advanced technology that leverages the great efficiency of refrigerant to deliver many benefits over water and air systems, and it’s appropriate to select designers and contractors with greater scrutiny.”
It is also difficult to know whether the Corps’ concerns have merit, because it is not clear why the decision was made to restrict VRF systems in the first place, said Armstrong.
“Speculation would suggest that their concerns are tied to refrigeration concentration issues,” he said. “If indeed that is their concern, design choices and product application can be managed to keep all people within a facility safe and secure. VRF design and application engineers have developed methods to mitigate risk and keep occupants out of harm’s way due to asphyxiation.”
Of course, the best way to ensure occupants won’t be harmed is to comply with all codes and regulations, which also apply to refrigerant used in any other HVAC system, said McGinnis. That includes complying with ASHRAE Standard 15, which specifies the safe design, construction, installation, and operation of refrigeration systems.
“For those who want additional security, there are small monitors that can be installed and set to detect refrigerant at a threshold that is lower than the maximum ppm,” said Armstrong. “These can provide an audible alarm or be set up to disable the system in the event a leak is detected.”
Reynal agrees that the safeguard is proper design and installation, which includes observing ASHRAE Standard 15.
“We reached out to the manufacturers that had 35 years of experience in Asia and Europe before introducing the technology to the U.S. and found zero history of asphyxiation related to VRF systems,” he said.
Regarding the Corps’ second concern that finding refrigerant leaks may be difficult due to VRF’s long refrigerant lines, it is true that all refrigerant systems could potentially leak. That said, VRF manufacturers have developed processes and training to support contractors through the VRF installation to ensure a high-quality refrigeration system, said Armstrong.
“When installed and commissioned to manufacturers’ specifications, there are rarely leaks in the refrigeration system,” he said. “Of course, leaks in these systems can happen when a pipe is pierced due to an outside source (work on the space, etc.), but as a rule, those leaks are not difficult to find, as piercing a high-pressure pipe will generally be visible and audible.”
Again, a properly installed VRF system should not leak, said McGinnis, but in the rare case it does, the leak usually occurs at the flare at the fan coil unit (FCU) or in the DX coil.
“The majority of VRF FCUs use flare fitting connections that, if not properly torqued, can become loose,” he said. “These are usually easy to find, and there should always be an access panel located next to these connection points. Most VRF manufacturers recommend re-torqueing the flare nuts after a certain amount of run time, so if contractors do their jobs correctly, there should not be any long-term leaks in the piping runs.”
The bottom line is that leaks are extremely rare when VRF systems are properly installed, added Reynal.
“The difference is that newer, advanced technologies require training, tools, and testing that are different than systems that simply move air or water,” he said.
Even though the Corps states that VRF systems’ proprietary controls are in conflict with the mandate to use open protocol systems, Reynal said that proprietary controls are much more common than previously thought, as most manufacturers internally control their refrigeration cycle utilizing proprietary communication.
“With VRF, because the components of the refrigeration cycle are located further apart, it makes it more noticeable,” he said. “Also, the controls common within VRF systems are meant for operating within the boundaries of the refrigeration cycle — they do not serve as a whole-building technology.”
Still, manufacturers have made significant improvements in their adaptability and compatibility to BACnet with their most recent series of equipment, noted Reynal, and there is nothing keeping the Army from having VRF systems monitored and managed through their existing BAS.
“We are seeing VRF manufacturers being super accommodating and providing universal integration,” said Reynal. “For instance, York provides what they call their Gateway for fast, simple integration of their VRF systems with BACnet, Metasys, or other BAS.”
Fujitsu systems are also easily connectable to both BACnet and LonWorks systems, giving facility managers access to all needed information, said Armstrong.
“Using the Fujitsu/Ventacity HVAC2 solution provides facility managers unprecedented access to system operation, including historical building operation, allowing predictive management options to save energy, improve reliability, enhance comfort, and advance future designs,” he said.
Daikin’s VRF system can also be integrated into any BAS, said McGinnis.
“The issue with the Corps is that they look at the VRF system as a multiple component system and not a single integrated system,” he said. “They need to realize that the VRF system is really a single system, just broken up into multiple components, none of which can operate on its own or within another manufacturer’s system.”
For example, a VRF heat recovery system has a condensing unit, changeover boxes, FCUs, and wall controllers, said McGinnis, and all these components use the same language in order to make the system work.
“You can’t expect someone else to properly integrate all those components together,” he said. “That’s why VRF manufacturers do not allow third-party direct digital control (DDC) controllers to rewrite the internal codes that make the systems tick.”
LIFE CYCLE COSTS
The uncertain life cycle costs of a VRF system, including operation and maintenance, are what caused the DoD to take a closer look at the technology. But all comfort systems have become more complex and require trained technicians who understand the equipment they’re working on, said Armstrong.
VRF systems require minimal maintenance — regular filter changes and coil cleaning will keep the system running efficiently for many years, he said.
“Like other VRF manufacturers, Fujitsu has worked hard to ensure that if and when there is a service issue, the part is easy to replace for quick return to service,” said Armstrong. “It should also be noted that Fujitsu systems, like many VRF systems, are easy to design for redundancy, so a single unit out of service will not take down the entire facility.”
In reality, there is just not much to maintaining VRF systems that other technologies don’t require, too, including filter changes, checking the condensate drains, and a seasonal washing of outdoor coils, said Reynal.
“With VRF systems, there is no cost for water treatment, monthly cooling tower service, or third-party BACnet services,” he said.
The high level of self-diagnostics that a VRF system provides may also make for shorter service calls, said McGinnis.
“When everything is taken into account, the overall ownership of a VRF system has been proven to be a lower life cycle cost than other traditional systems,” he said.
The case regarding the use of VRF systems on military bases is not closed, as manufacturers are working closely with the DoD to find common ground.
“Since DoD initially raised questions regarding VRF over a year ago, we and our industry colleagues have had a constructive dialogue to address the strongest concerns expressed by some within DoD,” said John Taylor, senior vice president of government affairs, LG Electronics USA Inc.
LG is looking forward to continuing those discussions with the DoD, and the company is confident VRF can meet operational efficiency goals without compromising mission-critical activities, said Taylor.
“DoD and the services continue to use VRF systems at over 150 of their facilities around the world, and the General Services Administration (GSA) has endorsed VRF, too, as an important technology for meeting energy efficiency goals in government buildings,” he said. “VRF has a long history of growing global adoption because it delivers high energy saving potential, minimum maintenance, low failure risk, and greater load management.”
Given all these benefits of VRF, Reynal expects the Corps to retract this directive in the near future. Meanwhile, he’s not too worried about it, noting that he has installed VRF systems on Army bases since the directive was published.
“We simply don’t have time to be too concerned,” he said. “We are extremely busy trying to keep up with demand.”
Publication date: 5/7/2018