Specifications

6 Cat 604-3
Features and Benefits
Open Choices™ BAS Flexibility
The exclusive Open Choices feature provides seamless
integration and comprehensive monitoring, control, and two-
way data exchange using industry standard protocols
LonTalk®, BACnet™ or Modbus™. Open Choices offers
simple and inexpensive flexibility to use the Building
Automation System of your choice without an expensive
gateway panel. Open Choice Benefits include:
• Easy to integrate into your BAS of choice
• Factory- or field-installed communications module
• Integrated control logic for factory options
• Easy-to-use local user interface
• Comprehensive data exchange
Compliance with ASHRAE Std. 90.1
According to ASHRAE, chillers usually spend 99% of their
operating hours at part load conditions and most of this time at
less than 60% of design capacity. Thus, the part load efficiency
of chillers is all-important.
ASHRAE Standard 90.1 was developed to assist owners and
designers make informed choices on a buildings design,
systems and equipment selection. Magnitude chillers can
significantly exceed ASHRAE 90.1 minimum efficiency
requirements.
Integrated Variable Frequency Drives
A Variable Frequency Drive (VFD) modulates compressor
speed in response to load and evaporator/condenser pressure.
VFD technology significantly reduces power input at part load
operation and at lower than design ambient temperatures.
The VFD can dramatically reduce annual energy costs when
there are long periods of part load operation and/or low
compressor lift (lower condenser water temperatures). The
attributes of VFD drives produce one of the industry's most
efficient single-compressor chillers based on the all-important
IPLV value. See IPLV/NPLV Defined inset for details on the
AHRI IPLV efficiency rating.
An additional benefit of a VFD is improved power factors. The
power factor will be 95% at 500 tons (AHRI conditions) with
the M3 low harmonic option, and 91% for the M2 standard
VFD (at 500 tons), which may help reduce power costs.
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. Low inrush current at startup is also ideal
for operation with backup or emergency power systems and
can reduce the size of backup generators.
Optional Harmonic Filter
An optional factory-mounted and wired or field mounted and
wired, passive harmonic filter is available for the WME 500.
Although the harmonic characteristics of the standard VFD
drive are acceptable in the vast majority of applications, this
filter is a cost effective option for those applications that
require reduced harmonics. Under most application conditions,
it is guaranteed to meet the IEEE Standard 519 for harmonic
levels.
Onboard Refrigerant Containment System
Pumpout systems are required on many jobs to collect and
contain the refrigerant charge when access to internal chiller
components is required for service. Magnitude condensers are
designed to hold the entire unit refrigerant charge (<90% full
and at 90°F (32°C) ambient temperature). When service is
required, the refrigerant charge can be pumped down into the
condenser by compressor operation and use of a refrigerant
transfer unit. Elimination of the cost and space requirements of
an external storage tank is a significant Daikin McQuay
advantage.
Unit Control Features
The Magnitude chiller control system consists of three major
components: the unit control panel and the operator interface
panel and the VFD power panel. The touch screen panel is on
an adjustable arm so that it can be positioned comfortably for
the operator. The control panel contains a USB port for
downloading the unit's fault history, major parameter trends,
and unit operating manual that is stored in memory.
IPLV/NPLV Defined
Part load performance can be presented in terms of
Integrated Part Load Value (IPLV), which is based on
AHRI standard rating conditions (listed above), or Non-
Standard Part Load Values (NPLV), which is based on
specified or job site conditions. IPLV and NPLV are based
on the following weighting equation from AHRI 550/590:
Using kW/ton, where:
A = kW/ton (or COP) at 100%
B = kW/ton (or COP) at 75%
C = kW/ton (or COP) at 50%
D = kW/ton (or COP) at 25%
Weighting
The percent of annual ton-hours of operation near the four
rated load points are as follows:
• 1% of operating ton-hours in the bin range 93~100%
load (represented by the rating at 100% load)
• 42% of operating ton-hours in the bin range 62~92%
load (represented by the rating at 75% load)
• 45% of operating ton-hours in the bin range 37~61%
load (represented by the rating at 50% load)
• 12% of operating ton-hours in the bin range 0~36%
load (represented by the rating at 25% load)
DCBA
IPLVorNPLV
12.0
+
45.0
+
42.0
+
01.0
1
=