TPC Sawgrass
TPC Sawgrass, the home of professional golf’s annual The Tournament of Players Championship now has nearly as many sustainable and eco-friendly practices inside as it does outdoors. They faced three HVAC challenges that arose during the design stage of their new clubhouse that are typical of Florida golf clubhouses:
1. Dehumidifying the outdoor air to code compliance and eliminate Florida’s typically high relative humidity (RH) thus preventing the likelihood of indoor mold/mildew.
2. Finding space for equipment large enough to dehumidify an estimated 974-lbs./hr (117-gal./hr) of humid outdoor air without taking excessive roof or space site.
3. Designing the system to meet TPC Sawgrass’ strict ongoing sustainability mission.
Now the new 77,000-square-foot-clubhouse carries on the sustainable tradition with Berner’s customized desiccant energy recovery, dedicated outdoor air system (DOAS) that saves the facility tens of thousands of energy dollars annually. The DOAS, which ties into the clubhouse’s overall HVAC water source heat pump (WSHP) loop for additional efficiency, dehumidifies the clubhouse’s 28,000-cfm of Florida’s year-round humid outdoor air that is necessary for indoor air comfort all while using 140 tons less refrigeration than a conventional HVAC system.
John Mayes, P.E., vice president, for the project consulting engineer, BAA Mechanical Engineers, Atlanta, specified two 100 percent outdoor air energy recovery units by Berner International. The Berner system uses enthalpy wheels combined with a recuperative loop process via their patented TRICOIL® technology. The units come with a factory-piped WSHP option, which eliminates the bulk and expense of exterior conventional condensers and allows heat rejection to the clubhouse’s WSHP loop. “These units assure that no outdoor air is introduced into the space with greater moisture content than a 55°F dew point”, according to Bill McClure, president, Allied Environmental Systems, Atlanta, a manufacturer’s representative that coordinated equipment speci cations between BAA and Berner.
On a 97°F Florida, summer day with 114.7 grains of moisture, the DOAS’s 75% efficiency enthalpy wheel cools the outdoor air to approximately 82°F and 78 grains of moisture. Then the air passes through the TRICOIL’s pre-cooling coil (first coil), where it continues to recover sensible energy from the outdoor air, and lowers it further to 67°F. A driver coil (second coil) connected to the WSHP condensing unit then dehumidifies the air further to the desired 55°F dew point. A thermostatic control on the coil’s leaving air side assures the air temperature doesn’t rise above the 55°F dew point. The air is then freely reheated to 69°F free with a third coil, a sensible reheat coil that accounts for an additional 40 BTUH of free reheat or equivalent refrigeration tonnage saved versus conventional systems using natural gas or electric heaters or reheat.
The Berner system design also features one of the smallest footprints industry, thus allowing the two units to fit on the small roof wells designed by project architect, Chapman Coyle Chapman Architects, Atlanta. This design keeps HVAC equipment off the grounds and out of sight. “We like the TRICOIL approach from the standpoint that it requires the industry’s least amount of refrigeration tonnage per cfm of outdoor air, plus there isn’t a DOAS brand that would have fit in the tight roof well space the architect wanted to employ,” said Mayes.
The TPC Sawgrass HVAC design has been successful on many other BAA engineering projects as well. “Even if this type of DOAS system wasn’t as efficient as it is, we’d probably still use it for dehumidifying the outdoor air, because it’s providing an incomparable indoor air comfort for the occupants,” Mayes concluded.