VRF Zoning: An Ideal HVAC Solution for Renovating

VRF Zoning:
An Ideal HVAC Solution
for Renovating Historic Buildings
White Paper
October 2013
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A proven HVAC technology worldwide, Variable Refrigerant Flow (VRF) zoning
systems are poised for dramatic growth in all areas of commercial construction
because they provide precise zoned control that can contribute to the achievement of
LEED®, Green Globes and ENERGY STAR® certifications.This paper describes the major
features and benefits of VRF zoning systems and how they are flexible, energy-efficient
HVAC solutions ideally suited for renovating historic buildings. Finally, this paper outlines how VRF zoning systems can help historic buildings earn a substantial number of
certification points.
VRF ZONING SYSTEM FEATURES
VRF zoning is a method of providing precise comfort control to buildings
with multiple floors and areas by moving refrigerant through piping to the
zone to be cooled or heated. Regardless of time of day, sun or shade, season of
the year or special requirements, VRF zoning systems provide personalized
comfort to each zone or space. The systems, which can simultaneously cool
some zones while heating others, have many features.
Design and installation flexibility. Components can be installed in tighter
spaces because they require less piping and duct space than conventional
systems. In addition, the system’s two refrigerant pipes and ductless
features require less installation time than conventional equipment and
other VRF system types.
Lighter weight. VRF zoning systems are 31 percent lighter than chilledwater systems, providing easier handling and less transportation cost. Also,
Muscatine County Courthouse, the load can be distributed across an existing structure, reducing structural
support needs over conventional equipment , or units can be mounted on the
Muscatine, Iowa
ground.
Discreet indoor units. A wide variety of indoor unit styles offer greater design flexibility. Styles include
wall-mounted, floor-standing (concealed and exposed) and vertical concealed. Ceiling options include
suspended, recessed and ceiling ducted.
Energy efficiency. Because its INVERTER-driven compressor in the outdoor unit varies the motor rotation
speed, the system is able to precisely meet each zone’s load requirement while reducing power consumption. As a
result, VRF zoning systems consistently perform at 25 percent higher efficiency than traditional systems.
Lower life-cycle costs. The total installed cost of a VRF zoning system is less than or equal to the total
installed cost of most conventional systems. Also, maintenance is greatly reduced and requires no special trades.
Energy savings above conventional systems along with first cost and maintenance cost reduction provides a
lower life-cycle cost for VRF systems.
Quiet operation. Unlike traditional systems that can start up and shut down with a bang, VRF zoning
systems operate at a whisper. The INVERTER-driven compressor modulates to ramp up and down to meet the
needs of the space reducing the noise associated with conventional system start up/shut down. The indoor units
operate at very low decibels as well providing a quiet indoor environment.
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Control options. Several controller types are available: wireless, wall-mounted and hard-wired. The central
controller can monitor, schedule and control up to 50 indoor units individually through a web browser interface.
Multiple central controllers can be networked together with the TG-2000 software and systems can be tied into a
BMS using LonWorks and BACnet protocals.
BENEFITS FOR HISTORIC
BUILDINGS
Union Mill, Baltimore
Historic buildings present unique challenges
when renovation includes adding or
updating the HVAC system. They often
lack the space for ductwork, and their
electrical systems probably weren’t
designed to handle modern central cooling
and heating requirements. What’s more,
installing a modern HVAC system while
preserving the architectural and aesthetic
integrity of an historic building is an
additional challenge. VRF zoning systems
are particularly smart HVAC choices for
meeting these unique challenges. Here’s
why:
The systems can be installed with minimal
impact on the building’s architecture and
daily operation. The flexible and modular
systems range from ductless systems that
install into tight spaces to low-profile ducted
systems. And indoor units can be mounted
just about anywhere—on the ceiling, wall,
floor, in a closet—to blend with the décor
and furnishings. As a result, high ceilings
and period finishes can be preserved—very
important to the aesthetics of historic
buildings.
Another plus for older buildings: because
VRF zoning systems can heat and cool
Miami University, Oxford, Ohio
simultaneously and equipment can fit into
tight spaces, units can be dedicated for small loads. For example, elevator machine rooms and computer
rooms require cooling year round while other areas require heat.
VRF zoning systems have minimal impact on building exteriors, too. Condensing units are compact and
light enough to be placed on a roof without compromising the structural integrity of the building. And, in
addition to small penetration holes, the small refrigerant lines can be easily camouflaged on the outside of
the building if they cannot be run inside the building.
These systems can also help renovation projects comply with requirements of the U.S. National Park
Service and U.S. Interior Department for rehabilitating historic buildings. Those requirements call for
preserving distinctive materials, features, finishes and construction techniques. VRF zoning systems meet
these requirements because they are minimally invasive, and components are flexible and unobtrusive.
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Architectural Preservation
“This VRF Zoning system was a great match for [the client’s] aesthetic goal of keeping the interior spaces’
natural look of brick and timber. In this old factory, there was no option for the typical mechanical room,
and with this Mitsubishi Electric system there was no need.”—Frank Hartley, Dynamix Engineering Ltd.,
project manager for Turner Construction Company’s renovated headquarters in Columbus, Ohio
“The interior would have been severely cut up with a hydronic
four-pipe system.”—Doug Hammerle, director of energy systems for
Miami University, Oxford, Ohio, about the benefit of the VRF two-pipe
system in renovating two historic buildings
Flexible Installation
“The [VRF zoning] system’s refrigerant line lengths allow us to be
really flexible about where we locate our condensing units and where
we route the refrigerant lines. [The system] allows us to maintain
high ceiling heights” and “hide the equipment.”—Austin Allen,
Henderson Engineers, Inc., Kansas City, Kan.
“I liked the fact that this was easy to install in a historic home and
provided simultaneous cooling and heating from one bedroom to the
next.”—Dave Hamilton, field service, EMCOR Service/Tucker Mechanical,
Meriden, Conn., about the Ronald McDonald House installation
Georgia Power Coastal Regional Office,
Savannah, Ga.
Easier, Quieter Installation
“Because WR2 Series units, (water cooled systems) are installed
indoors, we did not have to drill through the thick limestone walls,
which would have made quite a racket.”—Heath Allard, president,
Climate River Valley, HVAC contractor for the Muscatine County, Iowa
Courthouse renovation
Energy Efficiency
“The thing that most impresses me about the Mitsubishi Electric VRF zoning technology is the
combination of 100 percent INVERTER-driven compressors, quiet and premium efficiency indoor units,
free integrated energy recovery and, lastly, no need for supplemental electric resistance heating. To the
best of my knowledge, this operation is unique in the HVAC industry.”—Mike Babcock, Sustainable Building
Partners, energy engineers for the renovation of Union Mill, Baltimore
“When you have the proper HVAC technology, engineering and equipment, historic preservation and
energy conservation are a perfect partnership.”—Patrick Shay, Gunn Meyerhoff Shay Architects, who designed the
renovation of Georgia Power’s historic building in Savannah, Ga.
Precise Controls
“I can sit in my office and, with the Mitsubishi Electric software on my computer, monitor the temperature and
humidity in each room. This is vital because every collection needs a different setting.”—Emily Afflitto, site manager, Strawberry Mansion museum, Philadelphia
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CERTIFICATION PROGRAMS
VRF zoning systems can help historic renovations achieve certification by LEED, Green Globes and ENERGY
STAR programs.
LEED. The rating system recently increased its energy efficiency and outdoor air delivery requirements.
The updated version, LEED v4, adopted ASHRAE Standard 90.1-2010, which calls for a 30 percent energy
improvement over the 2004 standard. VRF zoning systems can contribute a significant number of points
in the Energy & Atmosphere (EA) and Indoor Environmental Quality (IEQ) categories. That’s because
the INVERTER-driven technology reduces energy consumption, allows precise comfort control, measures
performance, operates quietly and provides a dedicated outside air system with air-to-air energy recovery and
demand-controlled ventilation.
Green Globes. This alternative to LEED
could be especially useful for certifying
historical buildings. Green Globes, a web-based
program of the Green Building Initiative,
Portland, Ore., has eligibility requirements but
(unlike LEED) no prerequisites. Assessment
areas include energy efficiency, indoor
environment, emissions and environmental
management.
The same VRF features that earn LEED points
will help collect Green Globes.
ENERGY STAR. An estimated 85 percent
of Americans recognize EPA’s ENERGY
STAR label that denotes energy-saving
Turner Construction Company - Columbus Office, Columbus,
products—including buildings. To be eligible
Ohio
for ENERGY STAR certification, a building
must perform better than 75 percent of
similar buildings nationwide (the score accounts for differences in operating conditions, regional weather
and other important considerations). Information submitted in the certification application must be
verified by a licensed Professional Engineer (PE) or Registered Architect (RA).
The EPA notes that HVAC costs can be reduced by replacing chlorofluorocarbon chillers with energy
efficient equipment to meet cooling loads. VRF zoning systems do that and more. They also provide a
means for measuring and verifying energy usage—necessary for achieving certification from any of these
programs.
For more information about these certification programs, visit their websites:
LEED—www.usgbc.org; Green Globes—www.thegbi.org; ENERGY STAR —www.energystar.gov.
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CASE STUDY: Strawberry Mansion
Once a summer home, now a museum, Philadelphia’s 224-year-old Strawberry Mansion badly needed a
makeover. One of the most pressing needs was a new central HVAC system to replace the 1930s radiators
and piping.
“With 10,000 square feet on four levels, 23 rooms and
masonry-bearing walls, it was a challenge to find an
advanced cooling and heating system that would have
an unobtrusive impact on this historic house,” said Beth
Kowalchick, who headed the committee overseeing the
project. Owned by the Philadelphia Parks & Recreation
Dept., “The museum had never been centrally air
conditioned, and it badly needed climate control for our
antique collections.”
Strawberry Mansion, Philadelphia
The old stone walls could not accommodate the 24-inch
openings required by a 4-pipe water source heat pump
system. And in some rooms there was no space for ducting
or an indoor fan coil. The 2-pipe VRF zoning system not
only solved these problems but saved the owners $50,000
upfront, compared to the 4-pipe proposal.
“There is no HVAC system and technology better suited to historic preservation and adaptive reuse,”
said Jeff Harper, Carter Mechanical, Inc., HVAC engineer and contractor for the project. “In addition to
the non-invasive piping and wiring, no manufacturer offers such a wide diversity of indoor air handlers
and flexibility of refrigerant lines. Where there was no space for an indoor unit at Strawberry Mansion,
Mitsubishi Electric offered us a vertical air handler that we could build into a bookcase. No one knows
it’s there because the operation is so quiet. Where there was no space for ductwork, we simply installed a
convenient wall-mounted unit.”
The new HVAC system has made “a remarkable difference” since the renovation was completed in May
2013, Kowalchick said. “Our collection has suffered from decades of no air conditioning or humidity
control. After a few months, I could see a noticeable difference in the appearance of our [antique
collection].”
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CASE STUDY: Muscatine County Courthouse
It had become all too clear that the 106-year-old County Courthouse in
Muscatine, Iowa, needed new parts.
“We found water in the basement from the old boilers, and the pipes
were starting to leak,” recalled Sherry Seright, county budget director.
“The indoor units were loud, moldy and fuzzy, and everyone disliked
the huge, ugly condenser unit sitting prominently on the roof of our
handsome Beaux Arts building, spoiling the view.”
The county board of supervisors went looking for a new HVAC system
that would not only preserve the historic structure without busting the
budget, but would also significantly reduce energy consumption. They
settled on Mitsubishi Electric’s VRF zoning system together with
a closed-loop geothermal system. The water-source heat pumps and
companion Dedicated Outside Air System (DOAS) work especially well
in Iowa where winters can be frigid and summers hot and humid.
Muscatine County Courthouse,
Muscatine, Iowa
Another major benefit: because of the minimal amount of construction
and demolition required, installation had less impact on the 24-inchthick limestone walls and did not disrupt work in the building. In fact,
“judges were holding court [during the transition], so we could not
afford to have a lot of banging and pounding,” Seright said.
In addition, the new VRF zoning units are small enough to be easily
transported down the stairs to the basement of the courthouse. And by
connecting to the geothermal loop, backup heat would not be needed. What’s more, the geothermal loop
transfers excess heat to the new jail addition across the street.
“We are all thrilled with the performance of this technology partnership,” Seright said. “As budget
director, I can tell you the clearest proof of the success of our decision came when the 30,000-square-foot
new jail addition came online and was tied into the campus geothermal field between both buildings. The
energy bill did not move up one tick!
“Perhaps best of all,” she continued, “we were able to remove that hideous chiller on the courthouse’s roof
that spoiled its classic lines.”
Visit this and other commercial case studies at www.mehvaccasestudies.com.
For more information about Mitsubishi Electric HVAC products, visit www.mitsubishipro.com.
Mitsubishi Electric Cooling & Heating
1340 Satellite Blvd. NW
Suwanee, Ga. 30024
800-433-4822