Carrier 19EF Series, Руководство по запуску и эксплуатации

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After removing heat from the water, the refrigerant vapor
passes through the compressor first stage, is compressed and
discharged into the compressor second stage. Here it is mixed
with flash-economizer gas and is further compressed.
Compression raises the refrigerant temperature above that
of the water flowing through the condenser tubes. When the
warm (typically 95 to 105 F [35 to 41 C]) refrigerant is dis-
charged into the condenser, the relatively cool condensing
water removes some of the heat and the vapor condenses
into a liquid. In water chilling machines, further removal of
heat occurs in the thermal subcooler at the bottom of the
condenser. Here the liquified refrigerant is subcooled by con-
tact with the coolest (entering water) condenser tubes.
The liquid refrigerant drains into the flash economizer where
a valve system helps maintain pressure intermediate be-
tween the condenser and the cooler pressure. At this lower
pressure, part of the liquid refrigerant flashes to gas, thus
cooling the remaining liquid. The flash gas is returned di-
rectly to the compressor second stage. Here it is mixed with
gas already compressed by the first stage impeller. Since the
economizer gas has to pass through only half the compres-
sion cycle to reach condenser pressure, there is a savings in
power, hence the term ‘‘economizer.’’
The cooled liquid refrigerant in the economizer is me-
tered through the low-side float chamber to the cooler. Be-
cause cooler pressure is lower than the economizer pressure,
some of the liquid flashes and cools the remainder to cooler
temperature. The cycle is now complete.
MOTOR COOLING CYCLE
Refrigerant liquid from a sump at the bottom of the con-
denser is subcooled by passage through a line immersed in
the refrigerant within the cooler. The liquid then enters the
compressor motor end where it sprays on and cools the com-
pressor rotor and stator. It then collects in the base of the
motor casing and drains back into the cooler. Refrigerant gas
is vented from the compressor motor casing and returns to
the upper portion of the cooler through a check valve. Dif-
ferential pressure between condenser and cooler maintains
the refrigerant flow.
COND
WATER
COMPRESSOR
MOTOR
COOLING
CIRCUIT
FLOW
EQUALIZER
PLATES
CHILLED
WATER
THERMAL SUBCOOLER
CONDENSER
LIQUID LEVEL
SENSOR LINE
HIGH SIDE
FLOAT VALVE
CHAMBER
HIGH SIDE
FLOAT
CHAMBER
LOW SIDE
FLOAT VALVE
CHAMBER
ECON GAS
DAMPER
FLASH GAS
CHAMBER
DRAIN
COMPRESSOR
COOLER
CONDENSER
FLASH ECONOMIZER
CHILLED
WATER
REFRIGERANT VAPOR
REFRIGERANT LIQUID
Fig. 3 — 19EF Refrigeration Cycle
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