Ask any member of the executive sales team at Mitsubishi Electric US, Inc. Cooling & Heating Division (Mitsubishi Electric) how the cooling and heating industry has changed over the last decade and they’ll have no shortage of words. They’ll tell you how technological innovations in HVAC (heating, ventilation, and air conditioning) have led to seismic shifts across the building industry, from dramatic energy and cost savings, to improved thermal control and increased occupant comfort.

At the cutting edge of this change, according to Mark Kuntz, senior vice president of sales, marketing, product strategy and engineering for Mitsubishi Electric, is the company’s Variable Refrigerant Flow (VRF) zoning technology, an energy-efficient, ductless cooling and heating system which Kuntz says is revolutionizing HVAC. Gone is the labyrinthine of duct work and cobwebbed boiler rooms. In their place, Kuntz says, is a system that is easier and more affordable to install and maintain, that comes with tighter more individualized control, and uses less energy.

Too good to believe? Perhaps. But use of VRF technology globally and in the United States is widespread and growing. Mitsubishi Electric alone, one of a dozen or so players in the market, has more than 15,000 systems active in the United States and Canada and has been recognized with awards ranging from the US Green Building Council’s 2014 Best of Building Award in the HVAC/Indoor Air Quality/Building Controls category to Plant Engineering magazine’s Product of the Year Silver Award for its Hyper-Heating INVERTER (H2i) CITY MULTI R2-Series VRF Zoning System. Their technology is seen in LEED-rated projects and retrofits across the nation, from single-family passive and net-zero homes, to schools, restaurants, residential skyscrapers, even the corporate offices of multi-state energy companies who pride themselves on efficiency.

Mark Kuntz, senior vice president of sales, marketing, product strategy, and engineering at Mistubishi Electric.
Mark Kuntz, senior vice president of sales, marketing, product strategy, and engineering at Mistubishi Electric.

“Right now, VRF technology has about 6% share of the cooling and heating market in the US, “ Kuntz says. “We see this continuing to grow into double digits in the next five years.”

Here’s a closer look at how the technology, invented in Japan, has affordably furnished the renovation of the one-hundred-year old David Whitney Building in Detroit, saved 25% in energy costs within two years of installation at Screven Elementary School in Sylvania, Georgia, and prompted industry competitors to rethink their product strategy.

Some Like it Hot. Others Don’t.

Mitsubishi Electric Cooling & Heating retrofit the David Whitney Building with more than 600 tons of Variable Refrigerant Flow (VRF) technology, while preserving the 19-story skyscraper’s historic character in Detroit’s hot new urban core 

At the junction of Park Avenue, Woodward Avenue, and Washington Boulevard within Detroit’s resurgent Grand Circus Park Historic District, stands the renovated and nearly fully occupied David Whitney Building—a gem of a skyscraper in the Neo-Renaissance style, designed by the legendary architectural firm Daniel H. Burnham & Co. A century after its 1915 construction, the building’s restoration is a sign, like the arrival of corporate offices for companies like Twitter, Shinola, and Compuware, of the resurgence of Detroit’s urban core.

Named after the wealthy lumber and shipping baron David Whitney Jr., who made his fortune in white pine, the building, with its terra cotta and glazed brick façade, is regarded for its four-story skylit atrium adorned with ornately carved marble and gold leafing. It was once a premier address for some of the city’s best medical professionals, but, like many of Detroit’s historic skyscrapers, fell out of use as a result of disinvestment and the exodus of people from the city.

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A century after its 1915 construction, the David Whitney Building’s restoration is a sign, like the arrival of corporate offices for companies like Twitter, Shinola, and Compuware, of the resurgence of Detroit’s urban core.

After sitting vacant for 15 years, the building, which overlooks Comerica Park (home of the Detroit Tigers) and was bought by the joint venture Whitney Partners LLC for $3.3 million dollars in 2011, is once again prime real estate. The $94.5 million renovation led by the Roxbury Group has resulted in 108 apartments, a boutique 136-room hotel called Aloft Detroit (part of Starwood Hotels & Resorts), a bar and lounge, and the Grand Cirque Brasserie restaurant expected to open later this year.

A major part of the renovation, led by local HVAC contractor RW Meade & Sons, was retrofitting the entire building with more than 600 tons of Variable Refrigerant Flow (VRF) technology from Mitsubishi Electric. Not tons of material weight, rather tons calculated by ice melt— the century-old mechanism for translating heat production into a measurable unit: the amount of ice that melts in one hour as a result of heat absorption. In modern construction, the conversion is a rough indication of a project’s size: about 400 square feet per ton, according to Will Scott, commercial sales manager at Mitsubishi Electric.

At 19 stories, the sheer size and mass of the David Whitney Building, not to mention its 22- to 28-inch-thick flooring, presented an immediate heating and cooling problem, says Vince Dattillo, vice president of construction and project management at the Roxbury Group. Forced air involving ductwork would have meant high installation costs and difficult work in crawl spaces.

Graphic_3According to Scott, Mitsubishi Electric’s CITY MULTI R2-Series Heat Recovery VRF system (the company’s energy-efficient, cooling and heating system), a modular design that lends itself to widespread line sets, eased installation by limiting welded connections and cutting labor costs and time. Led by foreman Andy Peters, a team from RW Meade & Sons unspooled 82 foot-long, pre-insulated lines of copper refrigerant piping, manufactured in Italy and locally distributed, from air-cooled outdoor units on the roof and in the basement. With few restrictions on the placement of tee and elbow joints, these lines were connected to branch circuit controllers on each floor, allowing for independent temperature control in as many as 16 indoor units per floor.

Scott is quick to point out that the system’s benefits go beyond ease of installation. The apartments in the building, nearly fully leased, cater to the increasing number of young professionals moving to Detroit’s urban core to work and live. Satisfying the comfort needs of this millennial set, as well as international hotel guests, required a precise system with versatility and individualized control.

Graphic_5Miles“In a hotel and apartment, there are wildly different comfort demands. Of the two, hotels are more challenging. A visitor from the Middle East might want his room at 80 degrees, while someone from Canada wants hers at 68-69 degrees,” Scott says. “Whether guests are male or female, how much they weigh, personal preferences, these all come into play; individual comfort and control is of great value in a hotel.”

Producing adequate heat to keep occupants warm in a cold Detroit climate was a major challenge, Scott says, particularly in light of the project’s historic preservation guidelines requiring the single pane windows to be preserved. In each hotel room, temperature is controlled by modulating an electronic expansion valve within the indoor unit.  Occupants in adjoining or nearby rooms can use heating or air conditioning as they wish without greatly compromising efficiency. Large open areas, such as the atrium; one- to two-bedroom apartments; and hotel rooms all operate in different thermal zones.

Graphic_Scott says the key to the system is the high-powered variable speed, inverter-driven compressor, which can be up- or down-throttled like a gas pedal, to progressively match output to conditioning requirements. Through a sophisticated system of heat exchange, surplus energy rejected from a space is transferred to where it is most needed. “No other VRF manufacturer can hold a candle to Mitsubishi Electric when it comes to how well our engineers have designed the collection of components and the inverter-driven compressor to achieve optimal performance and efficiency. Mitsubishi not only manufactures its own compressors, but everything down to the solenoid valves, microprocessor controls, and electronic components to ensure systems work together for optimal performance. It really makes a difference when you have sole source construction,” Scott says. “Others may be able to deliver this kind of heat with a ‘four-cylinder,’ but to keep up with our ‘eight-cylinder,’ they have to operate on overdrive. Our system is designed to do this.”

Mitsubishi Electric’s CITY MULTI VRF systems require little upkeep other than filter changes to the indoor air handling units and outdoor unit condenser coil cleanings. A control system, integrated into the building through BACnet, is monitored remotely by Scott Mondock, Aloft’s director of engineering. It is fully integrated with the CITY MULTI VRF system to track energy performance down to the indoor unit and condenser, allowing for off-site equipment audits and limiting the need for service calls, according to Mondock. 

Graphic_2Perhaps just as significant as the energy performance and lifecycle benefits of the system are the reported cost savings over a water source heat pump system, what Scott says was the next best alternative. A lower “first cost” purchase and installation price reduced the project’s budget from $6.8 million to $5 million. And against baseline estimates for a comparable heat pump model, Mitsubishi Electric’s CITY MULTI R2-Series Heat Recovery VRF system is reporting an average of 10% lower energy costs annually, Scott says.

Ultimately, Scott is pleased to see the David Whitney Building energizing Detroit’s broader revitalization. “It was breathtaking to see the transformation of this high-rise building, abandoned and neglected for decades, into this beautiful architectural gem for city of Detroit,” he says.

Go Variable or Go Home

Japanese innovation and American muscle collide in Mitsubishi Electric Cooling & Heating’s high-powered compressor that is turning the HVAC industry upside down

More than a decade ago, David Archer, LEED AP, was on a travelling sales and training call for Mitsubishi Electric. David was one of the first people authorized to sell the company’s line of Variable Refrigerant Flow (VRF) technology in the United States, an energy-efficient cooling and heating system that company executives believed could transform the HVAC industry by making building conditioning not only incredibly precise but more affordable and highly variable throughout a building. The people he was trying to convince, however, weren’t exactly chomping at the bit.

“The technology was so out front people would look at me like I had six heads,” Archer says. “‘You’re telling me you can show me how to simultaneously heat and cool a building with one compressor?’ People said that is crazy talk. Even contractors who signed on were getting the cost and doubling the price and labor in their heads.”        

That first year, Archer says, he worked on two or three installations. This year, as an application consultant for Mingledorff’s, Inc., a wholesale distributor for heating, ventilation, and air conditioning systems based in the southern United States, he has consulted on 200-300 jobs using Mitsubishi Electric’s VRF systems. With the support of contractors such as Dyess Air, engineers like Pruett, Ford & Associates, and clients ranging from school districts, to hospitals and the US Military, he says the momentum behind the technology continues to build.

3 condenser split: A design by Don Nichols, senior mechanical engineer at Strategic Energy Solutions, split the condensers across three areas – on the roof, in an alley and in the basement level area-ways of the David Whitney Building– to minimize the vertical travel distance of line sets, thereby staying within Mitsubishi Electric’s specifications.
3 condenser split: A design by Don Nichols, senior mechanical engineer at Strategic Energy Solutions, split the condensers across three areas – on the roof, in an alley and in the basement level area-ways of the David Whitney Building (pictured above)– to minimize the vertical travel distance of line sets, thereby staying within Mitsubishi Electric’s specifications.

Archer’s experience may be anecdotal, but use of VRF technology globally is widespread, and evidence of growth is supported by industry research. Mitsubishi Electric alone, one of a dozen or so players in the market, has more than 15,000 systems active in the United States and Canada and has been recognized with awards ranging from the US Green Building Council’s 2014 Best of Building Award in the HVAC/Indoor Air Quality/Building Controls category to Plant Engineering magazine’s Product of the Year Silver Award for its Hyper-Heating INVERTER (H2i) CITY MULTI R2-Series VRF Zoning System. Their technology is seen in LEED-rated projects and retrofits across the nation, from single-family passive and net-zero homes, to schools, restaurants, residential skyscrapers, and even the corporate offices of multi-state energy companies who pride themselves on efficiency.

Outside the United States, VRF systems are nothing new, Kuntz says; in fact, they dominate the market. According to Kuntz, VRF technology was invented and launched in Japan, where high-energy costs and government regulations against outdoor noise in densely populated cities, such as Tokyo, contributed to the rise of the quiet, energy efficient systems, which spread rapidly throughout the Pacific Rim and other continents before migrating to the United States.

So then, one might ask, how does the system work? Kuntz explains that unlike a centralized HVAC system, in which a chiller, boiler and pump are housed in one location, VRF zoning systems use distributed technology such that each floor has, fundamentally, its own separate system, which can be installed incrementally. Conditioned refrigerant—R410A, the industry standard—is piped directly to the zone where it is required, thereby eliminating incremental heat transfer loss and surplus component parts.

“A high rise building traditionally used a chiller and boiler system, pumping water to every zone in the building. The challenge is you have one massive machine generating hot water and a separate massive machine generating cold water,” Kuntz says. “Depending on conditions in the space, you are working at different levels of efficiency. If one component goes down, the entire system is at risk.”

Tight compressor speed control means better comfort for building occupants and improved energy and cost performance at the building level, Kuntz says. Because the inverter-driven compressor can operate at a fraction of its full load speed, throttling down when it needs to, it is not “oversized” for a building’s total energy load. And since rooms can be rapidly cooled or heated, a building operator can turn off the system in spaces that are unoccupied—saving energy while knowing these rooms will quickly return to the desired temperature once turned on.

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A wall-mounted indoor unit operating off the VRF system can produce conditioned air for an individual room, while being part of a larger cooling and heating system.

Ductless and VRF systems operate on three levels, Kuntz says, beginning with Ductless Mini-Splits with one outdoor unit serving a single indoor unit, then Ductless Multi-Splits with one outdoor unit serving up to 8 indoor units, and culminating with the VRF system with one outdoor unit serving up to 50 indoor units. At the highest level, Mitsubishi Electric’s heat recovery VRF systems are able to transfer rejected heat from the conditioning process to rooms internally, so nearby rooms or building areas can simultaneously be set at different temperatures—68, 72, or 78, for example—without compromising performance.

Energy-savings data from internally produced case studies of recently installed Mitsubishi Electric VRF systems support Kuntz’s assertion the technology is leading to significant cost and energy savings. The city of Sacramento, for example, recently replaced a four-pipe chilled-water and boiler system with a VRF system in The Sacramento Drill Tower, a 9,476 square-foot concrete water tank that contains offices for the city’s firemen, administrators, and IT personnel. City officials report a dramatic reduction in utility bills due to the new system: a total energy savings (kBtu usage) of 50%, and a total cost savings of 19%.

Then there is Wisconsin-based Franklin Energy, a firm one might reasonably imagine would be invested in energy efficiency. The company relocated their headquarters to the former Smith Brothers processing plant on the Lake Michigan shoreline, in January 2011, and installed a VRF zoning system. Using utility meter data and measured data from an energy monitoring system, performance data show significant energy savings compared to Commercial Buildings Energy Consumption Survey (CBECS) energy data for a building of comparable size and construction: 32% savings in electric energy use, (12.2 kWh/ft2/year), and 48% savings in gas energy (21.9 ft3/ft2/year).

PAC-YT53CRAU_18048In Mitsubishi Electric’s case study of Franklin Energy, Dave Janquart, a VRF specialist at Auer Steel & Heating Supply Co. in Milwaukee, who recommended the VRF installation in Franklin Energy’s headquarters, reports several additional advantages of the system, including ease of installation, the small footprint and lightweight of the outdoor units, and the ability for load-sharing not possible with conventional systems. 

Of course, with all of these benefits, one wonders why the technology has not been more eagerly embraced in the United States. Interestingly, Kuntz says, the innovation of Mitsubishi Electric’s VRF heat recovery system, which allows some building areas to operate in heating mode while others operate in cooling mode, presented early hurdles to US adoption, as industry testing protocols failed to accurately capture the system’s energy savings. A big part of what helped Mitsubishi Electric stake its claim as one of the most widely recognized, sought after VRF brands in the industry relied on convincing the US Department of Energy and the Air Conditioning, Heating, and Refrigeration Institute to adopt a new testing protocol, validated by an independent panel of engineers and experts. 

Although Mitsubishi Electric certainly has active competitors in the heating and cooling industry, Kuntz says many of them have been slow to embrace VRF technology, considering it a niche product. Only now are US heating and cooling manufacturers joining forces with Asian suppliers to compete in the VRF market: a few cases in point, Toshiba and Carrier, Trane and Samsung, and Johnson Controls and Hitachi. “We feel there are two major innovators, and a lot of followers. Daikin is our closest competitor in terms of innovation and development of VRF. We are in continuous competition on a global basis to shrink our footprint, lower our weight and refrigerant volume, and make our products better.”

Driving Mitsubishi Electric’s effort to stay ahead of the competition and keep up with the rapid proliferation of emerging thermal technologies in the built environment—for instance, an airless, chilled beam system that uses convection current to regulate temperature differential—is the recruitment of top-tier professionals from within and outside the industry, Kuntz says.

He adds that facilities investment has also been key. Just as Asian automobile manufacturers Honda and Toyota established US design and manufacturing centers to better reach North American consumers, so has Mitsubishi Electric. Mitsubishi Electric built a design and engineering center in Suwanee, Georgia, that allows US and Japanese engineers to work together while benefiting from technological expertise refined overseas. “We’re dedicated, in our DNA, to the ideas of quality and innovation,” Kuntz says. As a global 500 company, we have the long-view as to how that innovation and quality works and what the paybacks need to be. We’ve made a long-term commitment in investment in R&D.”

In 2012, William Bland, then-assistant superintendent at Screven County School System, had a difficult decision to make. Screven Elementary School in Sylvania, Georgia, a rural school that serves 1,400 students ranging from pre-K to fifth-graders, was operating on a dated and inefficient HVAC system sorely needing replacement. The pipes of the building’s original water-source heat pump system, installed in 1989, were corroded and water was dripping through the ceiling. “There was no question about the need for a renovation of the HVAC system at the elementary school,” writes Bland in a project report.

What remained a question, however, was how to renovate affordably, while increasing energy efficiency. One option was to replace the original water source heat pumps with new equipment. Another was to install wall-mounted units, designed by Bard, around exterior walls and use ducted package systems for interior rooms. To Bland, neither option was a clear-cut winner.

Eventually, he and other school representatives were invited to an educational session in Savannah, Georgia, led by Mingledorff’s, to learn about Mitsubishi Electric’s CITY MULTI Variable Refrigerant Flow (VRF) system as another alternative. “I clearly remember telling David Archer of Mingledorff’s that I would like to learn more and get more insight into the different systems, but I did not want to waste his time as I still did not think the CITY MULTI was for us,” Bland writes. Upon leaving the meeting and visiting a few sites using the technology, his attitude had changed. “We were very impressed and left that meeting with much more knowledge and an interest in learning more. The more we studied and researched and questioned other users, the more we liked the product.”

Mitsubishi_Screven_StatsThe installation, completed in less than 12 weeks, took place over the summer when school was not in session. Archer says the renovation has led to 25% less energy consumption and $16,266 in savings annually. Not only that, but it has helped Mingledorff’s sell the system to nearby school districts in Washington County and Effingham County, Georgia. “Most of the time, when you look at green solutions, you expect to pay a premium. But you almost have to be foolish not to embrace this for a school. You save 10% on the first cost, compared to a water source heat pump, then you save 25% in energy a year.”

In an internally produced Mitsubishi Electric case study, Mike Dixon, maintenance director for Screven Elementary School, says, “It was the energy efficiency that grabbed our attention. We were also interested in the ability of the units to maintain the temperature within one or two degrees and the quiet operation. It almost sounded too good to be true.”

Apart from its energy savings, Archer says, the system’s ability to transfer rejected heat through a branch circuit controller is well-suited for a school building where temperature can vary substantially by building wing, and room and children alternate between periods of seated instruction and activity. “Say one teacher has a whole bunch of kids that just came in from PE; they’re putting out heat and they are hot,” Archer says. “Next door, the classroom is clouded over. That classroom would get heat gain, while the other room would be cooled, via conditioned refrigerant circulated from room to room.”

The VRF system allows the Screven County School System to monitor and control the cooling and heating in individual classrooms on campus.
The VRF system allows the Screven County School System to monitor and control the cooling and heating in individual classrooms on campus.

The VRF system allows Preston Dees, director of school safety and energy manager for the Screven County School System, to monitor and control the cooling and heating in each classroom, according to the Mitsubishi Electric case study. “We were able to cut out another big part of our energy costs when we installed the new system because we were able to remove the old boiler and cooling tower,” Dees says. The boiler had provided heat, which was no longer necessary with the Mitsubishi Electric system. “We saved about two-thirds on our gas costs, so we’ve saved on energy and gas.”

Maintenance is also easier. The Mitsubishi Electric system is compartmentalized and distributed across 100 indoor air handling units, Archer points out, so if one component of the system goes down it can be fixed without requiring a total system shutdown and repair. “The greatest risk is losing 10-12 percent of the school at any given time,” Archer says. “With a water pump system, a single problem can take down a whole school.”


Mitsubishi Electric and the three-diamond logo are registered trademarks of Mitsubishi Electric Corporation. CITY MULTI and H2i are registered trademarks of Mitsubishi Electric US, Inc.