That’s how the subject headlined the good news on the March 22, 2011 email from Tommy Linstroth, president of the Trident Sustainability Group to the rest of the renovation team. The team had been working for the past 12 months on the new Coastal Regional Office for Georgia Power located at 28 Abercorn Street on Reynolds Square – one of six original squares in historic downtown Savannah.
“With great excitement, I’m happy to say we were officially awarded LEED Platinum for 28 Abercorn with a total of 84 points,” Linstroth said (a minimum of 80 points are needed for Platinum Certification). “Congratulations to all for Savannah’s first Platinum.
Built in 1920 as an automobile factory and supply store, 28 Abercorn Street is a two-story, 11,400-square-foot concrete structure which Georgia Power purchased for $2.6 million in November 2009 to consolidate its Coastal Regional operations from two buildings into one. Georgia Power wanted the 90-year-old structure to be a corporate metaphor for sustainability and green building practices.
“Going from two buildings to one and making it energy-efficient shows we’re willing to do what it takes to be a leader in saving energy,” says Cathy Hill, Georgia Power’s coastal regional vice president.
“From our very first meeting with the folks at Georgia Power and from the beginning of the design process, everyone agreed that our sustainability goal should be LEED 2009 NC Platinum,” said James (Jimmy) Swails, PE, LEED AP, principal for the Savannah engineering firm of Dulohery Weeks, Sustainable Engineering.
To achieve this goal, the design team set out to capture every possible credit for energy optimization. This strategy mandated a highly efficient HVAC system because of the high energy consumption (cooling and dehumidification loads) demanded by the Savannah climate. The relatively small project area, existing poured concrete structure and minimal space for ductwork narrowed the field of acceptable HVAC system choices. Swails along with Architect Patrick Shay, AIA, LEED AP, Gunn Meyerhoff Shay, Savannah, agreed to explore Variable Refrigerant Flow (VRF) zoning heat pump systems as a first choice.
Both firms had previous successful project experience with VRF systems from Mitsubishi Electric Cooling & Heating, Suwanee, Ga. Shay said, “We found them to be very efficient, flexible and especially suitable for historic building renovations and tight spaces.”
A LEED energy model confirmed that a VRF zoning system, coupled with a dedicated outside air system, high-efficiency lighting, selected day lighting, envelope improvements, solar thermal and solar photovoltaic would result in a 54 percent annual energy reduction compared to the ASHRAE 90.1 2007 baseline building. All possible credits were approved for energy optimization plus one additional point for exemplary performance. The VRF zoning system consisted of Mitsubishi Electric heat recovery heat pumps, branch controllers, wall-mounted ductless air handlers, ceiling-cassette and ceiling-concealed ducted air handlers, a controls network and Carrier i-Vu controls. The local Mitsubishi Electric distributor David Archer, LEED AP, Mingledorff’s, Inc., Savannah, was instrumental in providing product data, application guidance and engineering support.
“Our first design priority was a desire for superior energy efficiency,” Swails said. “This meant specifying the most energy-efficient HVAC system in the industry today. The second priority was a strong need for excellent zoning controls due to the many executive offices and conference rooms included in the renovation. The third priority was the need for installation flexibility and small ductwork due to low headroom and the poured concrete structure of the 1920’s building. The ductless VRF equipment allowed us to integrate many small ductless air handling units, refrigerant piping, drain piping and small ventilation and exhaust ductwork into the historic fabric of the building in a concealed manner. Mitsubishi Electric’s ductless technology was a perfect fit.”
“It’s almost impossible to achieve LEED Platinum without high levels of energy efficiency,” Linstroth said. “A quarter of the required points to reach Platinum can be earned under just the Optimized Energy credit, with another 10 percent under renewable energy systems. We knew from the outset that to get Platinum, it was going to take superior energy efficiency combined with renewable energy generation. In fact, we had such great success with each that we earned additional points for exemplary performance and regional priority credits.”
For Project Manager Don Coughlin, Gochnauer Mechanical, Hilton Head Island, S.C., exemplary performance at 28 Abercorn was all about ease of installation and technically advanced equipment. “With this Mitsubishi Electric VRF zoning system, the start-up is a breeze– you simply turn it on and it takes off and runs. We turned it on four months ago and haven’t heard from our client once. That’s what I call exemplary,” Coughlin said.
“Congratulations to our talented sustainability design team who brought us LEED Platinum,” said Cathy Hill, coastal regional vice president, Georgia Power. “A Platinum designation for our beautifully restored Coastal Regional Office is the finest reminder for those we serve that we are passionate about conserving energy.”
“When you have the proper HVAC technology, engineering and equipment, historic preservation and energy conservation are a perfect partnership, like hand-in-glove,” Shay said. His firm’s sizeable portfolio demonstrates the success of this “partnership.”
“Historic buildings designed before air conditioning often have high ceilings, tall windows and no space for ductwork. The VRF split-ductless, two-pipe system designed by Mitsubishi Electric enabled us to maintain the beauty and integrity of these generous spaces by providing a wide variety of indoor air handlers connected through minimal piping and wiring to the outdoor condensers. Through the ingenuity of INVERTER technology, we can supply the ultimate in precise indoor comfort control which leads to LEED credits and significant energy conservation,” Shay concluded.