« Back to Facilities Management News Home
Randolph Community College uses one of the nation's first combination of active chilled beams, dedicated outdoor air and off-peak ice storage.
For Immediate Release
Asheboro, N.C.--Engineers and architects took the seemingly impossible task of recycling an outdated industrial factory into a LEED® Gold showcase of the HVAC industry's most innovative equipment for Randolph Community College (RCC).
Transforming the former 46,000-square-foot, $850,000 Klaussner Furniture Plant's un-insulated brick shell into a high efficiency educational facility proved challenging for two Raleigh, N.C. firms, consulting engineering firm, Progressive Design Collaborative (PDC) and architecture firm, Smith Sinnett Architecture.
With the encouragement of RCC's Cindi Goodwin, director of facilities at the Asheboro, N.C.-based technical school, PDC's Scott Ennis, P.E., project engineer, and Steve Campbell, P.E., president, thought well beyond convention. They designed one of the nation's first combination of active chilled beams with an off-peak hours ice storage/chilled water loop.
The foundation of the Continuing Education and Industrial Center's (CEIC) cooling system is 184 IQHC active chilled beams and two Pinnacle® dedicated outdoor air systems (DOAS)--both products manufactured by SEMCO, Columbia, Mo. The chilled water loop is supplied by a 130-ton Model CGAM air-cooled chiller with scroll technology manufactured by Trane, Tyler, Texas; and an ice storage system by Calmac, Fair Lawn, N.J. All mechanical systems were installed by American Industrial, Greensboro, N.C.
The two-pipe chilled beams, which range from 2 to 10-feet in length, supply 100-percent of the $7.6-million facility's cooling. Chilled beams have the potential for condensation in humid environments such as North Carolina. Therefore PDC's DOAS specification delivers dry outdoor air to the chilled beams to prevent condensation and comply with ASHRAE Standard-62. Besides providing a comfortable relative humidity (RH), the DOAS/chilled beam cooling strategy's comparatively small six-inch-diameter ductwork saves significant ceiling space. Chilled beams also use approximately 40-percent less fan horsepower versus the alternative of a conventional rooftop and ductwork system. "We wanted to keep ceiling heights at 10 feet, so the inherent feature of the active chilled beams' reduced duct sizes caught our interest," said Scott Ennis, who had never specified a chilled beam project before, but is already specifying them again for a hospital with low ceilings.
Besides indoor air comfort, the two 10,000-cfm DOAS systems also add to the project's sustainability and IAQ, because they use molecular-sieve enthalpy wheel technology to dehumidify outdoor air and recover heat from exhaust air for pre-heating outdoor air. Versus silica gel desiccant wheels, the DOAS' molecular-sieve technology quickly adsorbs the exhaust air's moisture, but not its contaminants that can potentially pollute incoming outdoor air and degenerate IAQ. The enthalpy wheel also uses acid-resistant, anti-microbial and anti-stick coating treatments that help sustain the equipment's lifecycle and helps maintain design static pressures.
The CEIC's comprehensive energy savings result in a six-year payback of the mechanical, electrical and plumbing specification with the following equipment generating the greatest savings:
· chilled beams and energy recovery DOAS;
· ice storage;
· variable frequency drives (VFD) on the piping loops and DOAS fans;
· high-output T-8 fluorescent lighting by Philips Lighting with occupancy sensors Wattstopper, Santa Clara, Calif.;
· variable air volume (VAV) boxes with their own dedicated hot water loop;
· solar domestic hot water heating system by Lochinvar, Lebanon, Tenn.;
· a 3,200-gallon rainwater harvesting tank;
· polypropylene manufactured by Aquatherm, Lindon, Utah, was used on piping runs less than three-inches in diameter. The pipe is less expensive to produce, install and run, and it helps attribute to LEED credits;
· and various other MEP equipment.
The payback is reduced to four years when considering the $60,000 utility rebate. Duke Energy/Progress Energy offered the incentive because the CEIC's chiller operates mostly at night and is needed rarely, if at all, during daytime high-peak electric rate periods, according to David McDaniel, sales engineer at Trane manufacturer's representative, Brady Services Inc., Morrisville, N.C.
When compared to a more conventional design, such as ASHRAE-dictated constant volume package rooftop HVAC units with VAV boxes, the college is saving 28.2-percent with PDC's innovative mix of high efficiency technologies.
The LEED 2.2 project's HVAC equipment is also racking up approximately seven credits of the total 41-credits submitted for LEED Gold certification.
The CEIC, which is also the first North Carolina community college project to become a Challenge Partner of the U.S. Department of Energy's Better Building Challenge program, also uses a separate hot water loop and VAV box hot water coils that are supplied by two Lochinvar, Lebanon, Tenn., condensing boilers and VFD-controlled pumps by Bell & Gossett, Morton Grove, Ill. Specifying a separate heating loop saved tens of thousands of dollars in installation labor and material costs versus piping hot water to each chilled beam.
Design Decisions
The building envelope was a LEED challenge for Smith Sinnett architect, Robert Carmac, AIA, LEED AP, BD+C, because it lacked a vapor barrier, insulation and other modern energy-efficient building materials. The original building's wall and roof insulating values were low at R-3.45 and R-7.17, respectively. However spray foam insulation was able to increase the wall and roof R-values to R-14 and R-30, which are considerably higher than the minimum building code of R-5.7 and R-15, respectively.
Based on the project's energy efficiency, many of the CEIC's HVAC technologies will be combined in future PDC projects, especially schools and hospitals, according to Ennis and Campbell.
Converting an old warehouse into a sustainable showcase was a challenging project. Therefore, RCC proudly promotes the project's energy savings with its BuildingLogiX, Vandalia, Ohio, building automation system's EcoRate dashboard. The wall-mounted dashboard in the CEIC's lobby allows any visitor touch-screen access to a real-time analysis of the facility's ongoing water and energy savings. ###
About SEMCO: Since its founding in 1963 as a sheet metal fabrication company with five employees, SEMCO has built a reputation as a worldwide product innovator in the science of air movement, noise abatement, energy efficiency and indoor air quality with more than 300 employees and more than 300 manufacturer's representatives. Major product lines include spiral metal HVAC duct, energy recovery equipment, chilled beams, and acoustics equipment. SEMCO is a Fläktwoods company based in Columbia, Mo. SEMCO operates three manufacturing facilities in Morrilton, Ark., Petit Jean, Ark., and Roanoke, Va. SEMCO also operates an ASHRAE 84-compliant research and development facility dedicated to the innovation of new products for the 21st Century and beyond. For more information, please visit www.semcohvac.com; email sales.semco@flaktwoods.com; or call 1-888-473-6264.
