Chillers, vsd's are Rx for medical center's new emergency room wing
Case in point: University Medical Center (UMC) recently completed a new, 56,000-sq-ft emergency room addition to complement its 1.2 million-sq-ft, 508-room health care complex. The new master-planned campus required a multidimensional upgrade to the medical center's chiller plant, and that's where York International Corporation (York, PA) teamed with Dunham Associates to provide the right prescription.
According to John McElhone, mechanical engineer for Dunham Associates, "We were asked by UMC to design a new central plant that would meet the cooling needs of the campus. The central plant would need to have enough reserve capacity to accommodate future expansions. It would also have to be efficient at part-load capacity since some of the new expansions wouldn't be complete for a couple of years."
To meet this need, York supplied a new, 1,000-ton Millennium chiller, variable-speed drive (vsd) retrofits on an existing pair of York 1,000-ton machines, new controls, translator gateways, and refrigerant recovery equipment.
Is it a significant capital investment? Yes, say UMC officials. But the new equipment is expected to save 2.4 million kWh/yr - or $149,000 in annual electricity costs - resulting in a simple payback of about three years.
Just what the doctor orderedUMC realized that it needed to plan for future expansions. So the medical center hired Dunham Associates, a local mechanical engineering firm, and worked closely with two of its engineers, McElhone and Ron Baron.
Dunham Associates helped UMC confirm that a new emergency room was a logical addition, and so was the chiller plant expansion. The mechanical system upgrade was motivated by the need for additional cooling capacity to ensure proper, reliable humidity control for the "ER," which opened in the summer of 2000.
"Reliable cooling was essential," says Chris Roth, UMC's director of plant operations. "Although we needed only about 260 tons of cooling, we decided to purchase a 1,000-ton chiller for future expansions that are scheduled to take place in a relatively short time."
The new Millennium chiller, which uses HFC-134a refrigerant, features a vsd and a harmonic filtration device, which eliminates harmonic current distortion that can disrupt electric and electronic equipment. The retrofitted, 1,000-ton centrifugal machines also use HFC-134a; in 1996 they replaced two competitive units that relied on ozone-depleting CFC refrigerants.
All three chillers now feature the OptiView microprocessor chiller control option. According to Roth, OptiView delivers real-time chiller operational data in an easily understood and amply illustrated graphical fashion.
"We wanted to be the first in Las Vegas to have the OptiView technology," he explains. "It was important for me to provide our plant operators with the most accurate and up-to-date information on chiller plant performance."
While new and upgraded chillers and control panels are critical to the mechanical plant's success, the project also features the York "gateway" communication interface, which allows the chillers and vsd's to communicate with the facility's existing Honeywell building automation system (bas).
"This part of the specification was required to provide more flexibility for our existing controls system and give us greater connectivity," Roth says.
Vsd's were selected because of their energy-reduction benefits. Working together, the drives are making a significant contribution toward the annual goal of $149,000 in energy savings. Using the average rate of $0.06/kWh, the vsd's will enable UMC to conserve approximately 2.4 million kWh each year. Based on these projections, the drives are pushing the project to realize a three-year payback, according to Roth.
"The savings with the drives were an integral part of selling this project to management," he emphasizes.
Ready to answer the callBased on what he's observed so far, Roth says the York equipment is operating beyond his expectations. That's no surprise: UMC chose the company because of previous, positive experiences and a long-standing relationship with York's sales and service staff in Las Vegas.
"We have a great rapport with our local York sales and service branch," Roth says, "and we have a long and successful operating history with York equipment."