Carrier AquaEdge 19XR Start-up, Operation And Maintenance Instructions Manual

Also see for AquaEdge 19XR: Controls operation and troubleshooting Start-up, operation and maintenance instructions Start-up, operation and maintenance instructions

Carrier AquaEdge 19XR Start-up, Operation And Maintenance Instructions Manual Manual pdf 7 page image

7REFRIGERATION CYCLEThe compressor continuously draws refrigerant vapor from thecooler at a rate set by the amount of guide vane opening. As thecompressor suction reduces the pressure in the cooler, the re-maining refrigerant boils at a fairly low temperature (typically38 to 42°F [3 to 6°C]). The energy required for boiling is ob-tained from the water flowing through the cooler tubes. Withheat energy removed, the water becomes cold enough to use inan air-conditioning circuit or process liquid cooling.After taking heat from the water, the refrigerant vapor is com-pressed. Compression adds still more heat energy and the re-frigerant 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 flowinginto the condenser tubes removes heat from the refrigerant, andthe vapor condenses to liquid. The liquid refrigerant passesthrough orifices into the FLASC (flash subcooler) chamber.Since the FLASC chamber is at a lower pressure, part of the liq-uid refrigerant flashes to vapor, thereby cooling the remainingliquid. The FLASC vapor is recondensed on the tubes which arecooled by entering condenser water. The liquid drains into a highside float valve chamber between the FLASC chamber and theeconomizer. The refrigerant is then metered into the economizer.In the economizer, due to lower pressure, as liquid enters thechamber, some liquid will flash into a vapor and cool the remain-ing liquid. The separated vapor flows to the second stage of thecompressor for greater cycle efficiency. A damper valve locatedon the economizer line to the compressor acts as a pressure-reg-ulating device to stabilize low load, low condensing pressure op-erating conditions. The damper will back up gas flow and there-by raises the economizer pressure to permit proper refrigerantflow through the economizer valve during those conditions.The cooled liquid left in the economizer flows through a lowside float valve and then into the cooler. The float valve forms aliquid seal to keep vapor from entering the cooler. Liquid refrig-erant passes through the low side valve into the cooler. The re-frigerant is now at a temperature and pressure at which the cyclebegan. Figure 3 summarizes the refrigeration cycle.ECONOMIZERCOOLERISOLATIONVALVE(OPTION)CHILLEDWATERCOMPRESSORIMPELLERSBACK PRESSUREORIFICE (INTEGRALTO MOTOR SHELL)OIL COOLERTHERMOSTATICEXPANSIONVALVE (TXV)ROTOR TRANSMISSIONORIFICEFITTINGDAMPERVALVEREFRIGERANTISOLATION VALVELOW SIDEFLOAT VALVEHIGH SIDE FLOAT CHAMBERHIGH SIDE FLOAT VALVECONDENSERWATERISOLATIONVALVE(OPTION) FLASC CHAMBERREFRIGERANTLIQUIDREFRIGERANTVAPORREFRIGERANTLIQUID/VAPORHOT GAS BYPASSHGBPVALVEFig. 3 — Refrigeration Cycle — 19XR Two-Stage Compressor Frame Sizes 6 and 7