ENGINEERING MANUAL OF AUTOMATIC CONTROL
CHILLER, BOILER, AND DISTRIBUTION SYSTEM CONTROL APPLICATIONS
291
CONTENTS
Chiller, Boiler, and Distribution System
Control Applications
ENGINEERING MANUAL OF AUTOMATIC CONTROL
Introduction ............................................................................................................ 295
Abbreviations ............................................................................................................ 295
Definitions ............................................................................................................ 295
Symbols ............................................................................................................ 296
Chiller System Control ............................................................................................................ 297
Introduction.......................................................................................... 297
Vapor-Compression Refrigeration ....................................................... 297
Vapor-Compression Cycle .............................................................. 297
Centrifugal Compressor .................................................................. 298
Reciprocating Compressor ............................................................. 299
Screw Compressor.......................................................................... 299
Absorption Refrigeration ..................................................................... 299
Absorption Cycle............................................................................. 299
Absorption Chiller............................................................................ 300
Chiller Control Requirements .............................................................. 301
Basic Chiller Control ....................................................................... 301
System Controls Which Influence the Chiller .................................. 301
Safety Controls................................................................................ 301
Chiller/BMCS Interface.................................................................... 301
Chilled Water Systems ........................................................................ 302
Central Cooling Plants .................................................................... 302
Single Centrifugal Chiller Control .................................................... 302
Single Centrifugal Chiller Control Application ................................. 303
Multiple Chiller System Control Applications....................................... 305
Dual Centrifugal Chillers Control Application .................................. 307
Similar Multiple Centrifugal Chillers Control Applications ............... 309
Equal Sized Centrifugal Chillers Control..................................... 309
Multiple Centrifugal Chiller Sequencing...................................... 311
Dissimilar Multiple Centrifugal Chillers Control ................................... 313
Alternative Multiple Decoupled Chiller Control .................................... 313
Combination Absorption and Centrifugal Chiller System Control........ 313
Chiller Pump Optimization................................................................... 314
Thermal Storage Control ..................................................................... 315
General ........................................................................................... 315
Control Modes................................................................................. 315
Cooling Tower and Condenser Water Control ..................................... 316
Cooling Tower Performance Characteristics ................................... 316
Cooling Tower Capacity Control ...................................................... 316
On-Off Cooling Tower Fan Control .............................................. 317
Two-Speed Cooling Tower Fan Control....................................... 317
Variable Speed Cooling Tower Fan Control ................................ 318
Single Cooling Tower Variable Speed Fan Control ................. 318
Dual Cooling Tower Variable Speed Fan Control.................... 320
Chiller Heat Recovery System ............................................................ 323
Free Cooling-Tower Cooling............................................................ 323
Tower Free Cooling, Dual Chillers................................................... 325