Pennsylvania hospital earns LEED certification for zero energy building design and green HVAC system
The University of Pittsburgh Medical Center set out to make its new $252 million Monroeville, Pa., facility the most sustainable of its 30-hospital network.
It succeeded: The design team delivered a building that’s saving an estimated $350,000 to $500,000 in annual energy bills, hospital officials say.
“Our HVAC system design exceeds ASHRAE (American Society of Heating, Refrigeration and Air-Conditioning Engineers) 90.1-2004 requirements, and when combined with reduced electrical and lighting loads, it’s saving an estimated 18 percent in energy versus the standard minimum construction requirements of a standard HVAC system,” said Matthew J. Stevens, a Leadership in Energy and Environmental Design-accredited professional and senior project manager with CJL Engineering in Moon Township, Pa.
CLJ handled the project’s mechanical, electrical and plumbing engineering work.
Stevens and CJL managing partner Matthew J. Sotosky, P.E., were members of a design team with Joseph T. Badalich, the medical center’s corporate construction project director, and architect Timothy Spence with firm BBH Design in Raleigh, N.C.
Spence is accredited by the U.S. Green Building Council in LEED building design and construction.
The design team’s green design for the 302,000-square-foot, 155-bed facility is LEED-silver certified. The facility’s sustainability measures haven’t gone unnoticed. It was recently awarded 2013 Project of the Year in the commercial category from the Pittsburgh-based Engineers’ Society of Western Pennsylvania.
“This is certainly one of the most, if not the most, sustainable hospital designs in the Mideast region,” said Badalich, who oversaw the project’s construction for University of Pittsburgh.
While some engineers rely only on major HVAC construction equipment to rack up LEED credits, CJL sees every green HVAC opportunity as critical to building performance, such as specifying doorways with air curtains for energy conservation. For the medical center, high-efficiency boilers, chillers and rooftop direct-expansion systems were major contributors to overall energy savings. However, Stevens added that if the energy escapes through doorways, it diminishes sustainability efforts. CJL specified 11 air curtains to protect all entrances from outdoor air infiltration.
Installed by the project’s mechanical contractor, Ruthrauff Sauer LLC, based in McKees Rocks, Pa., and manufactured by Berner International of New Castle, Pa., 10 of the air curtains are in-ceiling models that appear as flush grilles and supplement BBH’s lobby’s design.
The air curtains all draw clean air from the lobby through an integral diffuser. Other models need supply ductwork or take air from potentially contaminated, unconditioned air spaces above the ceiling.
Besides energy savings, the air curtains all have electric heaters to make the indoor air comfortable. The heaters are controlled with a delay that spot heats at a lower air velocity until the doorway area’s setpoint temperatures are reached.
The 11th air curtain is a conventional model mounted above the emergency room doorway. It saves energy, but also prevents infiltration of any idling ambulance fumes, which is a common hospital industry air quality problem.
All the air curtains use three-speed fans that can be adjusted for proper doorway sealing and minimal operational decibel levels. Berner International trained the building’s engineering staff to calibrate and maintain the units for peak performance and energy efficiency.
While air curtains helped contribute sustainability, most of the seven HVAC LEED credits were attributed to a combination chilled-water loop and rooftop/variable-air-volume design consisting of three high-efficiency, 750-ton water-cooled chillers by Trane and three 9.9 million British thermal unit boilers from Bryan Steam LLC, of Peru, Ind.; and one 6 million Btu domestic hot water boiler by Leslie Controls, Tampa, Fla. The boilers use variable frequency drives.
CJL also specified three 750-ton cooling towers by Baltimore Aircoil Co. of Jessup, Md.; five custom rooftop units with airflow ranging from 68,000- to 80,000 cubic feet per minute made by TMI Climate Solutions in Holly, Mich.; and pumps by Bell & Gossett in Morton Grove, Ill.
BBH’s building envelope design features low U-factor glass from PPG Industries in Pittsburgh, reducing the heat load enabled CJL to use smaller mechanical equipment, but attain the same indoor air comfort efficacy.
BBH and UPMC’s Badalich were very instrumental in getting the full green potential from the 17-acre site, which included razing the location’s former dilapidated hotel and asphalt parking lot. LEED-certification efforts included:
• Crushing the hotel’s concrete and reusing for the hospital’s foundation fill, which saved 6,500 dump truck trips to landfills.
• Positioning the building on the site for the most efficient use of solar gain in winter and using sunshades in the summer combined for heat load reductions of up to 17 percent.
• Eliminating rainwater runoff of the sloped site into a frequently flooded creek. Instead, storm water is naturally cleaned and evaporated through a series of rain gardens, bioswales and a retention pond to reduce runoff by 36 percent.
Because doorways are critical points for potential energy savings, Stevens said CJL’s future hospital projects will all consider air curtains combined with vestibules to increase energy-saving potential at entrances and enhance the entire sustainability design.
This article and its images were supplied Berner International Corp.