Carrier AquaEdge 19XR series - MOTOR AND OIL COOLING CYCLE

11
MOTOR AND OIL COOLING CYCLE
The motor and the lubricating oil are cooled by liquid refriger-
ant taken from the bottom of the condenser vessel (Fig. 4 and
5). Refrigerant flow is maintained by the pressure differential
that exists due to compressor operation. After the refrigerant
flows past an isolation valve, an in-line filter, and a sight glass/
moisture indicator, the flow is split between the motor cooling
and oil cooling systems.
COOLER
ISOLATION
VALVE
(OPTION)
CHILLED
WATER
COMPRESSOR
BACK PRESSURE
ORIFICE (INTEGRAL
TO MOTOR SHELL)
IMPELLERS
OIL COOLER
ORIFICE
OPTIONAL UNIT
MOUNTED VFD
(VARIABLE
FREQUENCY
DRIVE) HEAT
EXCHANGER
THERMOSTATIC
EXPANSION
VALVE (TXV)
FLOAT BALL VALVE
HGBP VALVE
ORIFICE
FITTING
MOISTURE/
FLOW
INDICATOR
FILTER
DRIER
REFRIGERANT
COOLING
ISOLATION
VALVE
ROTOR
TRANSMISSION
ORIFICE
FITTING
DAMPER
VALVE
REFRIGERANT
ISOLATION VALVE
HOT GAS BYPASS (OPTIONAL)
FLOAT
VALVE
CHAMBER
CONDENSER
WATER
FLASC CHAMBER
ISOLATION
VALVE
REFRIGERANT
LIQUID
REFRIGERANT
VAPOR
REFRIGERANT
LIQUID/VAPOR
MOTOR
Fig. 5 — Refrigeration Cycle — 19XR,XRV Two-Stage Compressor
IMPORTANT: To avoid adverse effects on chiller opera-
tion, considerations must be made to condenser water tem-
perature control. For steady state operation, the minimum
operating refrigerant pressure differential between cooler
and condenser is approximately 20 psi (138 kPa) with a
maximum evaporator refrigerant temperature of 65 F
(18 C). Consult Chiller Builder for required steady state
operational limits. Inverted start conditions are acceptable
for short durations of time, but for periods exceeding 5
minutes, a special control solution strategy should be used
to allow the chiller to establish a minimum refrigerant pres-
sure differential (and thereby adequate equipment cooling).