
10
REFRIGERATION CYCLE
The compressor continuously draws refrigerant vapor from
the cooler at a rate set by the amount of guide vane opening. As
the compressor suction reduces the pressure in the cooler, the
remaining refrigerant boils at a fairly low temperature (typical-
ly 38 to 42 F [3 to 6 C]). The energy required for boiling is ob-
tained from the water flowing through the cooler tubes. With
heat energy removed, the water becomes cold enough to use in
an air conditioning circuit or for process liquid cooling.
After taking heat from the water, the refrigerant vapor is
compressed. Compression adds still more heat energy, and the
refrigerant is quite warm (typically 98 to 102 F [37 to 40 C])
when it is discharged from the compressor into the condenser.
Relatively cool (typically 65 to 90 F [18 to 32 C]) water
flowing into the condenser tubes removes heat from the refrig-
erant and the vapor condenses to liquid.
The liquid refrigerant passes through orifices into the
FLASC (Flash Subcooler) chamber (Fig. 4). Since the FLASC
chamber is at a lower pressure, part of the liquid refrigerant
flashes to vapor, thereby cooling the remaining liquid. The
FLASC vapor is recondensed on the tubes which are cooled by
entering condenser water. The liquid drains into a float cham-
ber between the FLASC chamber and cooler. Here the Accu-
Meter™ float valve forms a liquid seal to keep FLASC
chamber vapor from entering the cooler. When liquid refriger-
ant passes through the valve, some of it flashes to vapor in the
reduced pressure on the cooler side. In flashing, it removes heat
from the remaining liquid. The refrigerant is now at a tempera-
ture and pressure at which the cycle began. Refrigerant from
the condenser also cools the oil and optional variable speed
drive.
The refrigeration cycle for a 19XR,XRV chiller with two-
stage compressor is similar to the one described above, with
the following exception: Liquid refrigerant from the condenser
FLASC chamber linear float valve flows into an economizer at
intermediate pressure (see Fig. 5). As liquid enters the cham-
ber, due to the lower pressure in the economizer, some liquid
flashes into a vapor and cools the remaining liquid. The sepa-
rated vapor flows to the second stage of the compressor for
greater cycle efficiency. A damper valve located on the econo-
mizer line to the compressor acts as a pressure regulating de-
vice to stabilize low load, low condensing pressure operating
conditions. The damper will back up gas flow and thereby rais-
es the economizer pressure to permit proper refrigerant flow
through the economizer valve during those conditions. The
damper also is closed during start-up conditions to allow the
second stage impeller to start unloaded.
The subcooled liquid remaining in the economizer flows
through a float valve and then into the cooler.
Fig. 4 — Refrigeration Cycle — 19XR,XRV Single-Stage Compressor
a19-
1550tf
Содержание AquaEdge 19XR series
Страница 69: ...69 Fig 33 19XR Leak Test Procedures a19 1625 ...
Страница 150: ...150 Fig 62 PIC II Control Panel Wiring Schematic Frame 2 3 4 and E Compressors without Split Ring Diffuser a19 1870 ...
Страница 152: ...152 a19 1871 Fig 63 PIC II Control Panel Wiring Schematic Frame 4 and 5 Compressors with Split Ring Diffuser ...
Страница 154: ...154 Fig 64 Benshaw Inc Wye Delta Unit Mounted Starter Wiring Schematic Low Voltage a19 1873 ...
Страница 161: ...161 Fig 69 Typical Low Voltage Variable Frequency Drive VFD Wiring Schematic 575 v ...
Страница 162: ...162 Fig 69 Typical Low Voltage Variable Frequency Drive VFD Wiring Schematic 575 v cont ...
Страница 163: ...163 Fig 69 Typical Low Voltage Variable Frequency Drive VFD Wiring Schematic 575 v cont a19 1880 ...
Страница 176: ...176 CONTINUED ON NEXT PAGE Fig 71 Typical Medium Voltage Variable Frequency Drive VFD Wiring Schematic cont a19 2064 ...
Страница 186: ...186 APPENDIX B LEAD LAG WIRING 19XR Lead Lag Schematic Series Cooler Flow a19 1655 ...
Страница 187: ...187 APPENDIX B LEAD LAG WIRING cont 19XR Lead Lag Schematic Parallel Cooler Flow a19 1717 ...