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CHILLER OPERATING PRINCIPLES
This section contains an overview of the operation of air-cooled liquid chillers equipped with thermostatic control
systems.
Note: To ensure proper diagnosis and repair, contact a qualified service organization if a problem should occur.
GENERAL
The large capacity chiller unit is a reciprocating type compressor air-cooled liquid chiller. This unit is equipped with
unit-mounted starter/control panels and operates with R404A or R448A refrigerant.
BASIC COMPONENTS OF A CHILLER UNIT:
•
Unit-mounted panels containing breakers, starters, and Carel controller
Reciprocating compressors
•
•
Brazed plate or shell-and-tube evaporators
•
Air-cooled condenser
•
Electronic expansion valves
•
Related interconnecting pipping
REFRIGERANT CYCLE
The refrigeration cycle of the large capacity chiller is conceptually similar to other G&D air-cooled chiller products.
The chiller uses brazed plate evaporators and an air-cooled condenser. The compressors use suction gas cooled
motors and an oil management system to provide almost oil-free refrigerant to the condenser and evaporator for
maximum heat transfer while lubricating and sealing compressor bearings. The lubrication system helps to assure
long compressor life and contributes to quiet operation.
Refrigerant condenses in the air-cooled condenser.
Liquid refrigerant is metered into the brazed plate evaporators using a thermal expansion valve to maximize chiller
efficiency at full and part load operation.
The chiller is equipped with a unit-mounted starter and control panel.
The PLC-based unit control module provides accurate chilled fluid control while providing monitoring, protection and
limit functions.
The adaptive nature of the controls intelligently prevents the chiller from operating outside of its limits, or
compensates for unusual operating conditions while keeping the chiller running rather than simply shutting off the
chiller.
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