Trane TRG-TRC010-EN Impeller Dynamics

24 TRG-TRC010-EN

notes

period three

Compressor Capacity Control

refrigerant. Recall that kinetic energy is converted to static energy, or static

pressure.

The radial velocity (Vr) for a given compressor is directly proportional (∝) to the

flow rate of refrigerant vapor through the compressor.

The tangential velocity (Vt) is proportional to the product of impeller rotational

speed and impeller diameter.

Therefore, the static-pressure-producing capacity of a compressor can be

adjusted by changing the flow rate of refrigerant, the impeller speed, or the

diameter of the impeller.

Impeller Dynamics

diameter

V

∝ refrigerant flow rate

refrigerant flow rate

V

∝ rotational speed × diameter

rotational speed × diameter

rotational

speed

refrigerant

flow rate

Figure35

trgtrc010_book.book Page 24 Wednesday, September 1, 1999 10:39 AM

Contents

Main BUSINESS REPLY MAIL Page Page Preface A Trane Air Conditioning Clinic Contents Page Introduction Chilled Water System helical-rotary absorption centrifugal Introduction Centrifugal Water Chillers period one period one Centrifugal Water Chiller Compressor Compressor Impeller Centrifugal Compressor Energy Conversion Multistage Compressor notes Condenser Condenser Expansion Device Orifice Plates Economizer Economizer notes Evaporator Evaporator Motor Motor gear-drive direct-drive Hermetic Motor Cooling notes Controls and Starter Controls and Starter Starters unit-mounted remote-mounted p h period two p-h) Pressure-Enthalpy ( liquid vapor Chart Page Page Refrigerants Refrigerant Operating Pressures Page Multistage Compressor Impeller 24 refrigerant. Recall that kinetic energy is converted to static energy, or static pressure. Impeller Dynamics V rotational speed diameter V Compressor Unloading full load part load Surge Compressor Map notes Operating Point 2-Stage Compressor Adjustable-Frequency Drives period four period four Maintenance Considerations ASHRAE Guideline 3 Page Mechanical Components Heat Transfer Surfaces Fluid Analysis notes Oil Analysis period five period five Condensing Temperature Control Condensing Temperature Control Cooling Tower Bypass Constant or Variable Evaporator Water Flow Constant or Variable Flow Limitations Short Evaporator-Water Loops Short Evaporator-Water Loops Heat Recovery Heat Recovery Heat-Recovery Chiller Options Free Cooling Free Cooling Refrigerant Migration Equipment Certification Standards ARI Standard 550/590 ARI Standard 550/590 notes period six ReviewPeriod 1 period six ReviewPeriod 2 impellers inlet vanes ReviewPeriod 3 impellers ReviewPeriod 4 ReviewPeriod 5 Engineers Newsletter Engineered Systems Clinics Quiz Questions for Period 1 1) 2) 3) Quiz Questions for Period 4 Questions for Period 5 Answers Standard for Water Chilling Packages Using the Vapor-Compression Cycle, Page notes 85577_Cover.fm Page 2 Wednesday, September 1, 1999 10:08 AM