Trane trg-trc005-en manual Air-Cooled Condenser Control, Condenser Flooding Control

Page 21

period two

Condensers

notes

Air-Cooled Condenser Control

damper

AB

condenser airflow

fan A

fan B

fan A

heat rejection capacity

Figure 21

A common method of controlling the capacity of an air-cooled condenser is to vary the airflow across the condenser coil. The heat-rejection rate of a multiple- fan condenser is often controlled by cycling fans on and off to maintain acceptable condensing pressures. Alternatively, the airflow across the coil can be varied by using a damper or a variable-speed drive on one or more of the fans.

In this example, a damper has been added to one of the two condenser fans. Capacity control is accomplished by cycling fan B on and off while varying the airflow of fan A by modulating the damper. Both the damper and the cycled fan are controlled by condensing pressure. As the heat-rejection requirement increases, fan A continues to open its damper farther to increase its airflow. When fan A reaches full airflow, fan B turns on and fan A modulates its damper to continue to match the desired heat rejection rate.

Condenser Flooding Control

B

C

A

liquid receiver

condenser

expansion valve

evaporator

discharge line

compressor

Figure 22

Another, less common method of controlling the capacity of an air-cooled

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TRG-TRC005-EN

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Contents
Air Conditioning Clinic Refrigeration System Components One of the Fundamental Series Comment CardBusiness Reply Mail Refrigeration System Components Refrigeration System Components PrefaceContents TRG-TRC005-EN Vapor-Compression Refrigeration IntroductionRefrigeration Cycle Refrigeration CyclePeriod one Condenser Condensers Air-Cooled CondenserAir-Cooled Condensers Effect of Subcooling Centrifugal Fan Air-Cooled Condenser Evaporative CondenserEvaporative Condensers Water-Cooled Condensers Water-Cooled CondenserCooling Tower Condenser Control Condenser Capacity Condenser Control Condensing Temperature Control Vary Condenser Water Flow Rate Vary Entering Water TemperatureCooling Tower Bypass Condenser Flooding Control Air-Cooled Condenser ControlCondensers Evaporators Finned-Tube EvaporatorFinned-Tube Evaporators Turbulent Flow Superheat Shell-and-Tube Evaporators Shell-and-Tube EvaporatorEvaporator Control Evaporator ControlFace-Split Arrangement Finned-Tube Evaporator Control80ºF Intertwined Arrangement Row-Split Arrangement Shell-and-Tube Evaporator Control Expansion Device Expansion DevicesTXV Control Thermostatic Expansion ValveTXV TXV TXV Operation Psia TXV Too much superheat Superheat SettingAccessories Solenoid ValveSolenoid Valve Period five Liquid-Line Filter Drier Liquid-Line Filter DrierSealed type Moisture-Indicating Sight Glass Moisture-Indicating Sight GlassSuction Line Filter Suction Line FilterHot Gas Muffler Hot Gas MufflerShutoff Valve Shutoff ValveAccess Port Access PortReview-Period One ReviewAir-cooled condenser Review-Period TwoReview-Period Four Review-Period ThreeReview-Period Five For more information, refer to the following references Questions for Period QuizQuiz To C To G AnswersGlossary Glossary Glossary Trane Company
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