Control Systems for Heating, Ventilating and Air Conditioning

ISBN-13: 9781468465952 / Angielski / Miękka / 2012 / 318 str.

R. Haines

Opis

There are two reasons why we have a new edition every four or five years. The first is that technology changes. Chapter 10, on computer-based con- trols, has had to be almost completely rewritten. Fundamentals don't change, but the tools available to us do change. Evaluation and proper use of those tools makes it even more imperative that we understand fundamentals. Many of our control problems stem from the use of new devices as a solution to problems that are, in fact, control design errors. New gadgets, for example, Direct Digital Controls (DDC), will not solve basic problems and may even compound them. None-the-Iess, you will find an extensive discussion of DDC because I think it is the probable "future" in HVAC control. But it must be applied with a good understanding of fundamentals. The second reason is that I keep learning and need to pass on my new and improved understanding to my readers. Thus you will find a number of small but important revisions, a dissertation on control "modes," and a much more detailed discussion of how electronic control devices work. There are a few places where I have corrected what I now perceive to be errors. I apologize for these. I have been much encouraged by the acceptance of this book in the past, and I hope that this new edition will be helpful. Thank you for your support.

Spis treści

1 Control Theory and Terminology.- 1.1 Introduction.- 1.2 What is “Control”?.- 1.3 Elementary Control System.- 1.4 Purposes of Control.- 1.5 Control Action.- 1.6 Energy Sources for Control Systems.- 1.7 Measurement.- 1.8 Symbols and Abbreviations.- 1.9 Psychrometrics.- 1.10 Relationships.- 1.11 Summary.- 2 Pneumatic Control Devices.- 2.1 Introduction.- 2.2 Pneumatic Control Devices.- 2.3 Control Cabinets.- 2.4 Air Supply.- 3 Electric and Electronic Control Devices.- 3.1 Electric Control Devices.- 3.2 Electronic Control Devices.- 4 Fluidic Control Devices.- 4.1 Introduction.- 4.2 Wall Attachment Devices.- 4.3 Turbulence Amplifiers.- 4.4 Vortex Amplifiers.- 4.5 Radial Jet Amplifier.- 4.6 Fluidic Transducers.- 4.7 Manual Switches.- 5 Flow Control Devices.- 5.1 Dampers.- 5.2 Steam and Water Flow Control Valves.- 5.3 System Gains.- 5.4 Summary.- 6 Elementary Control Systems.- 6.1 Introduction.- 6.2 Outside Air Controls.- 6.3 Air Stratification.- 6.4 Heating.- 6.5 Cooling Coils.- 6.6 Humidity Control.- 6.7 Dehumidifiers.- 6.8 Static Pressure Control.- 6.9 Electric Heat.- 6.10 Gas-Fired Heaters.- 6.11 Oil-Fired Heaters.- 6.12 Refrigeration Equipment.- 6.13 Fire and Smoke Control.- 6.14 Electrical Interlocks.- 6.15 Location of Sensors.- 6.16 Summary.- 7 Complete Control Systems.- 7.1 Introduction.- 7.2 Single-Zone Systems.- 7.3 Multizone Air Handling Systems.- 7.4 Dual-Duct Systems.- 7.5 Variable-Volume Systems.- 7.6 Reheat Systems.- 7.7 Heat Reclaim.- 7.8 Fan-Coil Units.- 7.9 Induction Systems.- 7.10 Unit Ventilators.- 7.11 Packaged Equipment.- 7.12 Other Packaged Equipment.- 7.13 Radiant Heating and Cooling.- 7.14 Radiators and Convectors.- 7.15 Heat Exchangers.- 7.16 Solar Heating and Cooling Systems.- 7.17 Summary.- 8 Electric Control Systems.- 8.1 Introduction.- 8.2 Electric Control Diagrams.- 8.3 Electrical Control of a Chiller.- 8.4 Electrical Control of an Air Handling Unit.- 8.5 Example: A Typical Small Air Conditioning System.- 8.6 Electric Heaters.- 8.7 Reduced-Voltage Starters.- 8.8 Multispeed Starters.- 8.9 Variable Speed Controllers.- 8.10 Summary.- 9 Special Control Systems.- 9.1 Introduction.- 9.2 Close Temperature and/or Humidity Control.- 9.3 Controlled Environment Rooms for Testing.- 9.4 Some Examples from Practice.- 9.5 Summary.- 10 Supervisory Control Systems.- 10.1 Introduction.- 10.2 Hard-Wired Systems.- 10.3 Multiplexing Systems.- 10.4 Computer-Based Systems for Monitoring and Control.- 10.5 The Economics of Supervisory Systems.- 10.6 Benefits of the Computer System.- 10.7 Training for Maintenance and Operation.- 10.8 Summary.- 11 Psychrometrics.- 11.1 Introduction.- 11.2 Psychrometric Properties.- 11.3 Psychrometric Tables.- 11.4 Psychrometric Charts.- 11.5 Processes on the Psychrometric Chart.- 11.6 HVAC Cycles on the Chart.- 11.7 Impossible Processes.- 11.8 Effects of Altitude.- 11.9 Summary.- 12 Central Plant Pumping and Distribution Systems.- 12.1 Introduction.- 12.2 Diversity.- 12.3 Constant Flow Systems.- 12.4 Variable Flow Systems.- 12.5 Distribution Systems.- 12.6 Building Interfaces.- 12.7 Summary.- 13 Retrofit of Existing Control Systems.- 13.1 Introduction.- 13.2 Economic Analysis.- 13.3 Discriminators.- 13.4 Control Modes.- 13.5 Economy Cycle Controls.- 13.6 Single-Zone Systems.- 13.7 Reheat Systems.- 13.8 Multizone Systems.- 13.9 Dual-Duct Systems.- 13.10 Systems with Humidity Control.- 13.11 Control Valves and Pumping Arrangements.- 13.12 Summary.- 13.13 Conclusion.- Control Bibliography.- Abbreviations Used in this Book.- Symbols Used in this Book.