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Controls Data and Connections |
Trane set the standard for unit microprocessor controls in
1985 with the first generation of UCP. Associated with this standard have been:
• Proportional Integral Derivative (PID) control
strategies which provide stable operation and high accuracy for better performance along
with feed forward plus.
• Adaptive Control™
to keep the chiller "on line" and at the same
time keep the chiller away from a major failure;
• Software based safeties that do not depend on
electromechanical hardware — hardware that means questionable reliability and added
cost;
• Operator interface that accesses chiller information
and control adjustments at the front of the panel.
Now — in addition to all of the capability that our
customers have come to expect — Trane offers UCP2.
Beyond the ‘traditional’ controls; beyond
‘traditional’ safeties; beyond ‘traditional’ chiller data
availability; and beyond the ability of the ‘standard’ chiller and its
associated controls to operate in ‘traditional’ systems, UCP2 adds more
flexibility, more reliability and better system performance than even our most demanding
customers expect.
Flexibility
Trane offers the ability to adapt to changes easily and
effectively without adding prohibitive cost. To provide flexibility, the controller
responds to a wide variety of needs for:
System Designs including equipment,
operating conditions, and controls variations that are either existing or being considered
for new installations.
Key to designing non-traditional systems is the ability
to evaluate the cost and reliability issues of these systems in comparison to the more
traditional systems. Trane recommends the use of C.D.S. Network Equipment Economics, the
Trane Applications Manuals, and consultation with a Trane sales engineer for help in this
analysis.
System Upgrades including the ability to accommodate
changes in the chilled water system design or equipment room requirements or to
accommodate new technologies that become available.
How does Trane demonstrate this flexibility:
• Modular structure or the UCP2 makes it possible for
the designer to select the system controls and associated interfaces to Tracer® (or other building
automation systems) that are required for the chiller plant design. With this modular
concept, capability can be added or upgraded at any time — with only temporary
interruption of chilled water production.
• The operator can quickly program a Custom Report
— so that only what is considered to be the most frequently accessed/important
reports are available — at any time, right at the front of the panel.
• With easy front panel programmability of Daily,
Service Start-up and Machine Configuration settings and setpoints, the operator,
serviceman, and system designer can customize the use of the micro controller to unique
conditions of the chiller plant — whether the purpose of chilled water is for comfort
cooling or for process cooling.
• All data that is necessary for the safe operation
and easy serviceability of the chiller is provided as standard on all Horizon™ absorption chillers.
Options are available that provide additional controls/data that are required for: an
industrial/process system design, applications outside of the typical chilled water system
design, the need for redundant machine protection, or the desire for more system
information.
Reliability
What does this mean and how do we do it?
To most people, reliability means "dependable —
giving the same result on successive trials." However, to our customers it has come
to mean "keep chilled water flowing." In other words, "when I turn the
switch on — cold water comes out." In order to do this, the micro controller
must be aware of what is happening in the system. But more importantly, it must be able to
make decisions and adjustments to keep the chiller running as long as possible even when
non-standard conditions exist. Conditions such as bad power or bad water (flow,
temperature, fouling) or system component failure. Also the Trane UCP2 panel continuously
monitors for noncondensables and purges automatically.
• With Enhanced Adaptive Control™ the controller does
everything it can toavoid taking the chiller off line.
— Senses potential overload, freeze and condenser
overpressure conditions
— Displays a warning message about the potential
condition/safety trip
— Take the following corrective action sequentially as
the condition worsens:
- limits loading
- prevents further loading
- unloads until condition improves
- takes chiller off line
• With more diagnostics and diagnostic history that
are time/date stamped and with help messages, the operator or serviceman can take faster
and more effective corrective action.
System Performance
"Chilled Water System" encompasses many levels of
control: Standalone Chiller, Chiller Plant, Applied System, Central Building Automation
System. However, regardless of the system level being design, the unit controls become
critical not just in making every level operate reliably but in facilitating optimal
performance. UCP2 provides more capability and more intelligence to make this
operation/optimization possible.
Panel Features:
The absorption chiller Unit Control Panel (UCP2)
incorporates the following features and components:
Control Functions
• Smart dilution cycle duration based on system
requirements
• Adaptive evaporator leaving fluid temperature
control
• Low evaporator temperature limit
• High solution temperature limit
• Solution flow control via AFD
• Softloading
• Nuisance trip prevention via Adaptive Control
• Chilled water reset
• Optimum concentration control
• Crystallization recovery via SDR
• High temperature generator pressure limit |
