David Whitney Building, Detroit
Vince Dattilo, vice president of construction and project management, Roxbury Group, knew his team had a big project ahead of it in bringing modern-day cooling and heating to the David Whitney. The building dates back to 1915 and sat vacant for 15 years before the renovation. The outdated mechanical systems needed updating but the sheer size and mass of the preexisting structure presented an immediate problem. “The floor is 22- to 28-inches thick. So right off, that made new HVAC challenging from a cost perspective. Forced air, which involves running tons of ductwork, would have meant high costs—if ductwork was even possible,” Dattilo recalls.
Cue Don Nichols, P.E., LEED AP, senior mechanical engineer with Strategic Energy Solutions. Nichols was given two determining factors whether VRF (variable refrigerant flow) was the most viable HVAC system: cost and energy efficiency. He explains: “Cost was about first cost. We compared two types of systems: water-source heat pumps and VRF. the construction cost for the VRF came in less than water-source heat pumps.”
Dattilo notes the VRF design used a pre-insulated line set distributed locally and manufactured in Italy. “We were looking at close to 5 miles of piping, so compare VRF to getting guys in here crawling through tight spaces to install insulation; that’s a lot of money saved on that one piece alone,” he adds.
Nichols’ consideration of energy efficiency was about long-term utility cost. “We did energy modeling for the building, looking at the yearly energy cost compared to a baseline of typical HVAC,” Nichols says. “Ultimately, VRF was a lower first-cost installation and lower utility operating costs.”
The result was that the original estimate of $6.8 million with a forced-air system came down to $5 million with VRF. VRF also maintained the building’s existing architecture. Contractor rick Mead, president, RW Mead & Sons, says: “We could not disturb any of the historically significant elements of the building. For renovating the historic building, VRF with its small-diameter piping rather than large-diameter forced-air ductwork made sense.”
Mead notes the installation went well. “Nichols’ design split the condensers across three areas—on the roof, in an alley and in the basement-level areaways—to minimize the vertical travel distance of line sets, thereby staying within Mitsubishi Electric specification,” he says.
Since installation, the VRF system has been keeping everyone comfortable while keeping costs down. Mead adds, “In January/February, the system was put to a test, and it provided the heat needed to make people happy and comfortable.”
Some of those people are guests in the 136-room Aloft hotel that occupies floors one through 9 of the building. Aloft’s Director of Engineering Scott Mondock describes the rooms as spacious with high ceilings. the vertical- and ceiling-concealed indoor units contribute to the rooms’ clean look and Mondock appreciates the system’s ability to cool and heat simultaneously. “the rooms are more evenly cooled/ heated,” he says. “The temperature stays consistent throughout the building with the system getting pretty close to the set points. older systems have at least a two- to five-degree differential. But with this VRF system you set it to 72 degrees and the system is usually within one degree of that, often right on the money.”Behind the scenes, the centralized controls system has been a boon to the entire building’s management team. Dattilo mentions: “The BACnet controls allow you to look at the system remotely—every fan coil, every condenser. We can set alarms. We can see what folks are doing 24/7/365.” Mondock uses the controls system to follow the system’s operation, establish set points and troubleshoot. “This is all by the touch of a finger on my cell phone, which is very nice and convenient,” he says. “I can access the system from my house or Colombia, and it responds quickly.”
VRF Manufacturer: Mitsubishi Electric US Inc. Cooling and Heating Division
According to the U.S. Census Bureau, Detroit lost 60 percent of its population from 1950 to 2010. The decline meant bankruptcy, myriad abandoned homes and buildings, high crime rates, even thousands of stray dogs on the streets. In the last two years, though, something has shifted; downtown activity has greatly increased thanks to a focus on rehabilitating historic buildings. Several projects are credited with this revitalization—among them the $94.5 million renovation of the David Whitney Building, a Class A skyscraper. the building has been restored to its previous grandeur and now offers luxury residences, the Aloft Detroit at the David Whitney, a restaurant and bar.
Ultimately, Nichols says: “The David Whitney is a big player in the Detroit revitalization. It’s been well-received and is in the heart of everything downtown. It’s an iconic place, and now it’s the hot spot in Detroit.”
PHOTOS: Mitsubishi Electric US Inc. Cooling and Heating Division