A Balancing ActAlthough its value as a historic landmark is limitless, the hotel's restoration budget was not. Developers P. Steven Dopp and Greg Lenox of Packwood Management, Charleston, SC, recognized the potential beneath the decaying facade, but they also had to watch the bottom line. The developers met their goals by installing HVAC equipment that kept first costs and operating costs within budget while providing the flexibility required in a restoration project.
"Our biggest challenge was to design and install air conditioning and ventilation equipment, ductwork, and piping in a building that was never meant for it," said Sam Stephens, engineer, Delta Engineering.
"Air conditioning barely existed in the 1920s. Because the hotel is listed on the National Register of Historic Places, all mechanical renovations had to fit within the original structure, so space was another limitation. The hotel had had window units for a number of years, but we took those out and installed piping and ductwork throughout. Because there were so many unknowns before we started, we had to be creative throughout the project, and that's why it's a success."
A Balancing ActThis balancing act of space-saving and flexible installation, combined with the economical operation required to meet budget requirements, was accomplished with McQuay chillers, rooftop units, AHUs, and fancoil units.
"We considered several different types of systems," said Stephens, "but a central system was the best fit for the application. It met the requirements for performance, price, space, and flexibility that we needed."
Two McQuay air-cooled reciprocating water chillers with MicroTech(tm) controllers form the core of the system. "There was no room for an indoor water cooled chiller, so we built a platform behind the hotel to house the chiller," said Stephens. To minimize installation costs, the chillers were factory assembled and wired.
Space also dictated the AHU installation. Three McQuay rooftop AHUs supply the main lobby areas and ballrooms. They draw in up to 100% OA, taking advantage of fresh, outdoor air cooling when outdoor conditions permit. The modular design of the rooftop units allowed them to be sized for the specific location at lower cost than a custom unit.
Knocking down walls or widening doorways to bring in HVAC equipment was not an option. The seven indoor AHUs had to be negotiated through stairwells, doorways, and tight corners. The McQuay Vision(tm) air handlers were shipped to the site in sections small enough to negotiate the interior.
In some cases, the units were knocked down even further to make it through the tightest spaces. When the equipment was in place, contractors had easy access to coil connections, vents, and drains because they extend outside of the cabinet, which helped to reduce installation time and keep the project on budget.
"In many cases, we were shooting in the dark," said Stephens. "The demolition of the interior had not been finished before the design began. This was a design/build project and scheduling was always important. We often encountered spaces where we had to adapt as we went, and that's where creativity came in."
Maintaining Original IntegrityA primary example is the four-pipe heating and cooling system that serves the hotel guestrooms. To maintain the hotel's original integrity, most guestrooms were kept to their original size, and the ceiling height left no room for ductwork. To save space, mechanical contractor David Hensley of Freeman Mechanical recommended McQuay Hi-Line fancoil units. "They are designed to be furred into the wall in the corner of each room - making them unobtrusive while providing quiet room conditioning," said Hensley. To work around structural interference, some of the fancoil units were fitted with special offset piping, which was factory-supplied to further save installation time and money.
During the two years that the hotel has been in operation, developer Steve Dopp has had no complaints. "It's critical for a historic hotel such as this one to have modern, efficient mechanical systems to provide excellent guest comfort. That was our goal when we started, and that is what we accomplished." ES