Specifications

Additional Compressor Design Benets
Model WMC’s magnetic bearing compressor design offers
many benets not only because of its oil free design but also
because of its use of a positive pressure refrigerant and a
variable frequency drive.
Environmentally Friendly
Over time negative pressure chillers (such as those using
HCFC-123) may draw air and moisture into the system, which
can signicantly increase energy consumption. Since the
Magnitude
®
WMC chiller uses a positive pressure refrigerant
(HFC-134a), the industry-leading efciency can be maintained
for the life of the chiller. In addition, HFC-134a has no ozone
depletion potential and no phase-out schedule per the
Montreal protocol unlike HCFC type refrigerants used in low
pressure designs.
Low Operating Costs
Model WMC offers world class part load efciency due to
its magnetic compressor design, which utilizes a variable
frequency drive. As a result, industry leading Integrated Part
Load Value (IPLV) ratings can be achieved. This allows for
signicant energy savings at off-design conditions compared
to xed-speed chillers. See AHRI Certication on page 6
for more information on IPLV ratings.
Integrated Variable Frequency Drive
A Variable Frequency Drive (VFD) modulates compressor
speed in response to load and evaporator/condenser
pressure. When minimum speed is reached, moveable inlet
guide vanes redirect the gas ow into the impeller. VFD’s have
the following benets:
• Reduced annual energy costs when there are long
periods of part load operation and/or low compressor lift
(lower condenser water temperature)
• Reduced motor starting inrush current
• Reduced size of backup generators used to provide
emergency power to chillers used on mission critical
applications
• Increased power factor to reduce utility surcharges
WMC Reduced Harmonic Option
The Institute of Electrical and Electronics Engineers (IEEE)
has developed a standard (IEEE519) that denes acceptable
limits of site specic system current and voltage distortion.
The designer may wish to consult this standard to ensure
acceptable levels of harmonic distortion are maintained.
The standard VFD includes 3% line reactors, which
dramatically reduce the harmonic distortion. An optional unit-
mounted harmonic lter is available for all models to meet
lower harmonic level requirements.
The Control Technology
It is only tting that this revolutionary chiller design be
matched with the advanced control technology to give
you the ultimate chiller performance. Our control design
includes many unique energy-saving features and interface
enhancements.
MicroTech
®
II Controller
The model WMC chiller utilizes MicroTech
®
II digital control
electronics to proactively manage unit operation and provide
control of external chilled water and cooling tower pumps.
The compressor runs at the minimum speed necessary to
maintain cooling capacity and lift (which decreases with lower
condenser water temperatures), thus minimizing energy usage
over the entire range of operating conditions. By constantly
monitoring chiller status and real time data, the MicroTech
®
II
controller will automatically take proactive measures to relieve
abnormal conditions or shut the unit down if a fault occurs.
Additional smart features that optimize operating efciency
have been incorporated into our MicroTech
®
II controls:
• Cooling tower control including on/off, staging, and VFD
• Direct control of water pumps
• Chilled water rest
• Demand limit control
• Ability to stage up to four WMC chillers
Operator Interface
Operation simplicity was one of the main considerations in the
development of the MicroTech
®
II control system. The operator
interface is a 15-inch, color touch-screen monitor that is
mounted on an adjustable arm. Key operating parameters and
setpoints are easily accessible. For added convenience, the
unit Operating and Maintenance Manual is also viewable on
the touch-screen panel.
In order to track chiller performance, the MicroTech
®
II
controller can record and plot water temperatures, refrigerant
pressures, and motor load. These values can be downloaded
through a convenient USB port in the interface and exported
into a spreadsheet for further evaluation and record purposes.
The trend history screen is shown in Figure 2.
www.DaikinApplied.com 5 CAT 602-4 • MAGNITUDE
®
MODEL WMC CHILLERS
feaTures and benefITs