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Posted on:
01/23/2006
New
Technology Combines With Renovation
The Result: Showplace For Cal State Campus
Installed inside the Acacia Court Building
is a McQuay frictionless chiller, with magnetic bearings, oil-free
compressors, and digital electronic
controls. |
STOCKTON, Calif. — The
expansive Acacia Court Building, originally a state hospital built in
the 1920s, has been given a new life. An extensive renovation has
converted this 100-yard-long concrete building into a showplace of
University Park, located in Stockton’s historic Magnolia District. The
Stockton Midtown neighborhood is being redesigned as a “live, learn,
work, walk” redevelopment, and Acacia Court is home to the satellite
campus of California State University, Stanislaus-Stockton.
Students and staff occupy part of the first floor of the sprawling
building; with future plans to include expansion into other sections as
well. The renovation draws on unique technology, including an HVAC
system designed around a new frictionless, magnetic bearing centrifugal
chiller, with impressive results. The chiller consumes far less power,
costs less to operate, and generates much less noise than conventional
chillers.
Four years ago, the Grupe Commercial Co., a California developer, was
awarded the University Park contract to develop the area into
educational, office, retail, and residential facilities, as well as a
community center. Over 32 buildings have been razed; 19 will be
renovated. Part of the goal is to keep floor plan changes to a minimum,
primarily as a renovate-to-suit project.
Working with chiller manufacturer McQuay and its representative,
Norman Wright Mechanical Equipment Corp., Grupe Commercial Co.
determined that the HVAC system was high on the list of systems to be
updated at Acacia Court. The existing system included two chiller units
dating from the 1950s, and some of the piping for them had collapsed.
“The efficiency of the old system was really poor,” said Chris
Rasmussen of Grupe’s facility management department. “We explained to
the university that the building needed a new chiller, along with new
piping and a cooling tower.”
NEW FOR THE
OLD
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The McQuay frictionless
chiller features magnetic bearing compressor technology that is
oil-free. This design is to significantly reduce sound levels, because
the magnetic bearings eliminate the metal-to-metal contact noise of
conventional bearings. According to the manufacturer, sound pressure
ratings are as low as 77 dBA per ARI Standard 575.
Energy performance is also considered revolutionary. The company’s
frictionless centrifugal chiller is designed to operate as low as 0.375
kW/ton IPLV. Full-load performance is supposed to be as low as 0.62
kW/ton — about 32 percent more efficient than screw compressor chillers,
said Daryl Showalter, director of marketing, McQuay chiller products.
“The magnetic bearing technology of the McQuay frictionless
centrifugal chiller provides superior energy efficiency by eliminating
the high friction losses of conventional centrifugal compressors,” said
Showalter.
“Variable-frequency drives unload the chiller to 10 percent of full
load. The chiller requires less than five amps to start, compared to 500
to 600 amps for a traditional screw compressor chiller. And, because
magnetic bearings require no lubrication, there is no need for oil
heaters, oil coolers, oil pumps, or oil
piping.”
GOOD
EXPERIENCE
The expansive Acacia Court Building was
originally a state hospital built in the
1920s. |
Despite the completely new
technology and design, installation went smoothly.
“We had a really good experience,” said Rasmussen. “We completed 90
percent of the installation work with our own maintenance staff, which
really helped reduce the cost. And since the system went online, there
has been zero unscheduled downtime because of problems, only scheduled
downtime for a couple of software upgrades.”
The two compressors of the frictionless chiller operate on a common
refrigerant circuit, designed to improve system reliability. In the
event of a mechanical or electrical problem, one of the two compressors
is designed to continue to operate until repairs can be made.
“If there is a problem with one compressor, we can still run with a
60-percent load on the other one,” said Rasmussen.
The MicroTech II™ digital unit controller on the chiller is designed
to effectively run and monitor the chiller operation. The chiller is
currently run based on a time clock input because there are not as many
maintenance issues with the magnetic bearing compressors. When the
budget allows, the staff can integrate the MicroTech II chiller using
BACnet®, LonTalk®, or Modbus® protocol, thanks to the Protocol
Selectability™ feature of the unit
controller.
SAVING BIG
TIME
“As
far as cost saving goes, it’s just incredible,” said Rasmussen.
“The old chiller required 1,000 amps per leg at start-up. By
contrast, when the new chiller starts up, each compressor takes only
seven to 10 amps. Also, it ramps up more slowly, so we don’t require a
big surge of electricity in the beginning, which would be quite costly
for the state.”
The chiller consumes far less power, costs less
to operate, and generates much less noise than conventional
chillers.
Maintenance is equally
worry-free. With the magnetic bearings compressors, the oil handling
equipment of the chiller is eliminated. According to the manufacturer,
there is no need for oil pumps, oil reservoirs, and/or oil coolers — and
their associated maintenance costs — that are needed to maintain oil
quality. The only requirement is to “punch tubes,” or clean the pipes
with a rotary brush, and blow out dust from the controls.
“That’s our PM [planned maintenance] for the chiller,” said
Rasmussen. “One other task we avoided is having to replace the
refrigerant type in the near future.”
The McQuay frictionless chiller uses HFC-134a refrigerant, which has
no phaseout date.
SUBTRACTING
NOISE
Noise is the other big plus
with the frictionless chiller — or rather, lack thereof, since noise is
virtually absent.
“We have an air compressor in the basement, and when the air
compressor is running, we can’t tell if the chiller is also running,”
said Rasmussen.
“We actually have to walk up to the unit to see if it’s still going.
We also have a couple of screw chillers at the university, and you can
hear them all the way up from the basement to the first floor. They’re
totally different from the McQuay chiller.”
For the university, the quiet new chiller makes the old building more
useable, as well as more efficient. While only a portion of the building
is currently occupied, development plans include moving other university
departments, as well as a computer lab, to Acacia Court.
Students and staff who use the building now and in the future will
benefit not only from the renovated building and its technologically
advanced chiller, but also the entire livable concept of the Magnolia
District.
For more information, see “Frictionless Compressor Chiller” at
www.go.mcquay.com. For the name of a local McQuay representative, call
800-432-1342 or visit www.mcquay.com.
Publication date: 01/23/2006
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