Specifications

12 Catalog 602-2
Unit Design Features
Variable Frequency Drive
Efficiency: The standard variable frequency drive
is a technology that has been used for decades to
control motor speed on a wide variety of motor-
drive applications. When applied to centrifugal
compressor motors, significant gains in part load
performance can be realized. The improvement in
efficiency and reduction of annual energy cost is
maximized when there are long periods of part
load operation, combined with low compressor lift
(lower condenser water temperatures).
The attributes of VFD and the compressor
technology produces one of the industry's most
efficient chiller based on the all-important IPLV
value. See “IPLV/NPLV Defined” on page 14 for
details on the
AHRI IPLV efficiency rating.
Starting Inrush: The use of a VFD on centrifugal
chillers also provides an excellent method of
reducing motor starting inrush-even better than
"solid state" starters. Starting current can be
closely controlled since both the frequency and
voltage are regulated. This can be an important
benefit to a building's electrical distribution
system. The low inrush feature, combined with two
one-half size compressors having a staggered start,
is particularly attractive where chillers will be
asked to operate on emergency generators. Since
inrush has much to do with sizing the generators,
much smaller generators can be used.
HFC-134a
Daikin McQuay Positive Pressure Design:
 No Purge
 No Vacuum Prevention System
 No Contaminants
HFC-134a operates above atmospheric pressure in
the entire refrigerant circuit and at normal
temperatures. All Daikin McQuay centrifugal
chillers use a positive pressure refrigerant, with the
following benefits:
 No absorption of impurities into the refrigerant
circuit
 No breakdown of motor insulation, refrigerant
or lubricant
 No increase in operating cost due to
displacement of heat transfer surface by non-
condensables
 No crevice corrosion and tube failure due to
moisture in the system
 No annual service expense to maintain and
rebuild purge unit
 No abnormal annual service expense for oil,
filter, and refrigerant replacement
 No periodic emissions of refrigerant into the
atmosphere
Heat Exchangers
Daikin McQuay Magnitude chillers are equipped
with high performance heat exchangers. The
unique design greatly increases heat transfer and
reduces unit footprint and refrigerant charge.
Vessels are designed, constructed and tested in
accordance with ASME Section VIII, ASHRAE
Standard 15 requirements and TEMA
recommendations.
The replaceable water tubes are internally rifled
and externally enhanced copper, and are
mechanically bonded to steel tube sheets. Standard
tubes are 0.025-inch wall thickness. Consult
factory for other options.
Vessels are available for 1, 2 or 3 pass water flow.
A 3/4" or 1-1/2 thick layer of vinyl/nitrate polymer
evaporator insulation is optional. All seams are
glued to form an effective vapor barrier. Detailed
information on the insulation can be found under
“Physical Data” on page 27.
Pumpdown
Pumpout systems provide a means to collect and
contain the refrigerant charge without loss when
access to internal chiller components is required
for service.
Daikin McQuay condensers and evaporators are
sized to hold the entire unit refrigerant charge
when not more than 90% full and at 90°F (32°C)
ambient temperature. They are equipped with
valves in the compressor discharge lines, suction
lines, and in the liquid line. These valves, coupled
with the vessel design, satisfy the stringent
requirements of the U.S. Department of
Transportation for refrigerant shipping containers,
as well as ASME vessel codes. When service is
required, the refrigerant charge can be pumped
down into either the condenser or evaporator by
compressor operation and use of a refrigerant
transfer unit.
Elimination of the cost and space requirements of
an external pumpout system on most jobs is a
major Daikin McQuay advantage.