Johnson Controls Central Plant Optimization 10 Product Bulletin

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Johnson Controls Central Plant Optimization™ 10
Product Bulletin
Code No. LIT-12011642
Software Release 10.1
Issued December 5, 2014
Refer to the QuickLIT website for the most up-to-date version of this document.
Johnson Controls has combined expertise from designing
YORK® chillers and Metasys® controls to bring the best,
world-class program to operate your chiller plant. The
result is Johnson Controls Central Plant Optimization™
10, which saves energy and improves reliability in your
Figure 1: Central Chiller Plant
A facility's central chiller plant uses a significant portion
of the total energy, typically 35%. Managing this load,
while still maintaining occupant comfort, is a primary
strategy for overall energy management. CPO 10, which
is powered by the Metasys® system, provides such a
strategy. The Metasys CPO 10 application uses
field-proven, factory-tested, and fully documented best
practices to select the most efficient combination of
chillers, pumps, heat exchangers, and cooling towers
needed to match the building load. The application then
commands the selected devices to the appropriate state
or speed, providing the necessary sequencing of pumps,
isolation valves, and main equipment, while observing
all the timing delays for safe and stable operation of the
central chiller plant.
Features and Benefits
Table 1: Features and Benefits
Advanced Control Algorithms
Evaluate all possible combinations of devices considering capacities,
efficiencies, runtimes, and number of starts, resulting in the most
efficient operating state, rather than simply selecting the next available
device as the building load increases.
Total Automation of All Equipment
Provides proper sequencing of all devices in a safe and stable fashion.
Simulation Mode Application Preview
Allows you to test a newly generated program prior to downloading
the program to the field controllers.
Optional Integration of Third-Party Equipment
Provides additional energy savings.
Control Sequences Created by the System Selection Allow you to select from tens of thousands of possible equipment
Tool (SST) within Controller Configuration Tool (CCT) combinations, piping configurations, and control strategies, each
resulting in the automatic creation of a software program using proven
best practices.
CCT Editor Allowing Customization of Individual
Components of the Program Created Using SST
Addresses special situations that cannot be described in SST and
easily customizes the program, without the need to build the entire
program from scratch.
Johnson Controls Central Plant Optimization™ 10 Product Bulletin
CPO 10 Applications
The CPO 10 application supports:
up to eight chillers, centrifugal (mix of constant or
variable speed), screw compressor, scroll
compressor, or reciprocating of mixed sizes, piped in
up to eight primary chilled water pumps of mixed
sizes, all dedicated or all headered, and all constant
or all variable speed
up to eight secondary chilled water pumps that are
mixed in size, are piped in parallel, and are variable
up to eight condenser water pumps that are mixed in
size, all dedicated or all headered, and all constant
or all variable speed
up to four heat exchangers of mixed sizes, piped in
up to eight cooling towers piped in common to the
chillers, are single speed (with optional vernier
control), multispeed, or variable speed, with a variety
of tower/sump valve arrangements
a non-integrated waterside economizer, able to control
up to eight total devices (chillers and heat
exchangers) piped in parallel
integration with Central Plant Optimization 30 (CPO
30), powered by Optimum Energy
air-cooled chillers
The CPO 10 application offers a variety of primary control
strategies including measuring building chilled-water flow
and differential temperature, the chillers’ kW load, flow
through a decoupler pipe in a primary/secondary system,
or differential temperature only in a constant speed chilled
water pump system. You can also select dozens of
secondary strategies, such as open loop control of the
cooling towers (as defined by the American Society of
Heating, Refrigerating and Air-Conditioning Engineers
[ASHRAE]), or closed loop control of condenser-water
The CPO 10 application can be configured for thousands
of plant configurations. Of these configurations, 24
common piping configurations can be created through
any combination of the following chilled water systems
and condenser water systems:
Chilled Water Systems
• Variable Primary Headered
• Variable Primary Dedicated
• Primary Secondary Headered
• Primary Secondary Dedicated
• Constant Headered
• Constant Dedicated
Condenser Water Systems
• Variable Headered
• Variable Dedicated
• Constant Headered
• Constant Dedicated
For more information on the 24 common piping
configurations, refer to the Johnson Controls Central Plant
Optimization™ 10 Application Note (LIT-12011575).
The CPO 10 application provides flexibility. You can
leverage or customize the supported standard
applications to meet the needs of specific job sites. For
example, you can customize the standard application to
support a mix of dedicated and headered chilled or
condenser water pumps. For more information, refer to
the Johnson Controls Central Plant Optimization™ 10
Application Note (LIT-12011575).
Sophisticated Control Algorithms
The CPO 10 application is much more than a simple
out-of-the-box program. The application uses many
sophisticated algorithms to determine the most efficient
set of equipment necessary to match the building load.
For example, if the building load increases beyond the
capacity of the current operating chillers, the CPO 10
application can calculate the estimated efficiency of all
possible chiller combinations. The application then selects
the most efficient combination, and determines the most
efficient combination of chilled water pumps, condenser
water pumps, and cooling towers necessary to
complement the chosen chillers.
The selections give preference to equipment with the
least runtime or number of starts for equipment with
comparable capacities and rated efficiencies, which
reduces equipment maintenance costs. The CPO 10
application proceeds to turn on or off the necessary
equipment, including isolation and bypass valves,
providing the appropriate timing to keep the entire plant
Johnson Controls Central Plant Optimization™ 10 Product Bulletin
As actual chiller lift (the difference between entering
condenser water temperature and leaving chilled water
temperature) varies from the design lift, The CPO 10
application adjusts the rated capacity of the chillers using
the manufacturer's specifications, allowing the plant to
take advantage of the added capacity before starting
additional equipment. In addition, for variable speed
chillers, the upper and lower optimal percent load points
(the percent of full load capacity where the chiller is no
longer efficient) shift down as measured lift decreases,
increasing the accuracy of selecting the most efficient
Once the software modules are linked, the tool allows
the entry of all equipment parameters, such as chiller and
pump capacities, minimum/maximum chilled and
condenser water temperatures and flows, rated
efficiencies, and sensitivity of chiller capacity to changes
in lift temperature. You can run the resulting program in
a simulator mode to verify proper operation before you
download the program into a Metasys® Field Equipment
Controller (FEC), Advanced Application Field Equipment
Controller (FAC), or Network Control Engine (NCE).
Figure 2: System Selection Tool
For variable primary flow systems, the CPO 10 application
can monitor the main chilled water coil valves throughout
the facility to reset the pump’s differential pressure
setpoint if no valves are fully open, resulting in lower
pump speeds and lower energy consumption. To prevent
an unreliable signal from a single valve from incorrectly
taking control of the reset program, the application uses
the average and standard deviation of the positions to
perform statistical tests, resulting in 97.5% assurance
that the valves are 100% or 90% open.
If building load continues to climb late in the work day,
the CPO 10 application can be programmed to coast,
which means the application does not start any additional
chillers, with the expectation that the cooling load soon
begins to decrease. The program also accounts for
problems in the chiller plant. Equipment taken out of
service or exhibiting alarm conditions is easily removed
from consideration for selection. If the system cannot
maintain the chilled water setpoint for a specified time
period, the application automatically derates the operating
chillers to smaller capacities, then finds a more efficient
set of equipment to meet the load. This situation may
occur when outdoor temperatures exceed design days,
or in cases where tube fouling causes loss of chiller
Creating a Complex Program
without Programming
The CPO 10 application leverages the System Selection
Tool (SST), which is a control program generator that
relies on defining the characteristics of the chiller plant
and its control strategies.
After making the selections, SST generates a complete
program by linking together appropriate software
modules, each of which has been thoroughly tested and
documented. This process removes the variability
commonly found in totally custom-generated programs
using a traditional software program editor.
More Flexibility
The System Selection Tree provides multiple system
options, which can then be edited at the module level to
create customized control capabilities. The application
marks these edited modules so that you can easily
identify the parts of the program that are factory tested
and documented, and which portions are job-specific.
Johnson Controls Central Plant Optimization™ 10 Product Bulletin
Related Documentation
For information on how to configure Johnson Controls
Central Plant Optimization™ 10, refer to the Johnson
Controls Central Plant Optimization™ 10 Application Note
(LIT-12011575). For information on how to use System
Selection Tool, refer to the Controller Tool Help
Building Efficiency
507 E. Michigan Street, Milwaukee, WI 53202
Metasys® and Johnson Controls® are registered trademarks of Johnson Controls, Inc.
All other marks herein are the marks of their respective owners.© 2014 Johnson Controls, Inc.
Published in U.S.A.
Johnson Controls Central Plant Optimization™ 10 Product Bulletin

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