Automatic Controls for Heating and Air Conditioning

List of Symbols

Chapter 1 Sensors and Instrumentation


1.1 Temperature Sensing and Instrumentation


1.1.1 Non-electric Methods


1.1.2 Electrical Thermometers-Thermocouples


1.1.3 Electrical Resistance Thermometry


1.2 Humidity


1.2.1 Psychrometers


1.2.2 Non-electric Humidity Sensors


1.2.3 Electric Humidity Sensors

Chapter 2 Applications


2.1 Final Control Elements


2.1.1 Pneumatic and Electric Actuators. Positioners


2.1.2 Valves


2.1.3 Dampers


2.2 Domestic Heating Controls


2.3 Boiler and Chiller Controls


2.4 Air-conditioning Controls


2.4.1 Zoning


2.5 Solar Collector System Controls


2.6 Building Automation Systems


2.7 Plant and Room Transfer Functions

Chapter 3 Controller Mechanisms and Circuits


3.1 Pneumatic Control - Air Supply


3.1.1 Continuous-bleed Proportional Controller


3.1.2 Non-bleed Proportional Controller


3.1.3 Three-term Pneumatic Controller


3.2 Electric Controllers


3.3 Electronic Control


3.3.1 The Wheatstone Bridge as an Error Detector


3.3.2 Electronic Proportional Controller


3.4 Switching Thermostats and Humidistats


3.5 Step Controllers


3.6 Time Switches


3.6.1 Optimum Start Controllers


3.7 Thermostatic Radiator Valves

Chapter 4 Controller Characteristics


4.1 Proportional Control


4.2 Steady-state Responses in Proportional Control


4.3 Three-term Controllers; Proportional, Integral and Derivative Actions


4.4 Stability Limits with Continuous Controllers


4.5 Empirical Choice of Controller Settings


4.6 On/off Controllers


4.6.1 Thermostat with Zero Hysteresis, Controlling a Single Time Constant Process


4.6.2 Thermostat with Non-zero Hysteresis

Chapter 5 Basic Theory of Linear Automatic Control


5.1 Introduction to Closed-loop Negative Feedback Control


5.2 Transfer Function Description of Linear Systems


5.3 Laplace Transforms


5.3.1 Inverse Transformation


5.3.2 Complex Zeros


5.3.3 Transform Theorems


5.4 Application of Laplace Transforms to the Analysis of a Heat Exchanger


5.4.1 Heat Exchanger Response - without Controller


5.4.2 Heat Exchanger Response - with Controller


5.5 First-order Step Response


5.5.1 Time Constants of Simple Thermometer Bulbs


5.6 Second-order Step Response


5.6.1 Dynamic Response of Second-order Transfer Function


5.6.2 The Effects of Gain on Steady-state Response


5.6.3 Second-order Step Response Performance Specifications


5.7 Higher-order Systems and Stability


5.8 Routh's Criterion


5.9 Roots of Polynomial Equations


5.9.1 Root-Locus Plots


5.9.2 Distance-velocity Lag; Pade Approximation


5.10 Frequency Response Plots


5.10.1 Asymptotic Approximations in Bode Plots


5.11 The Nyquist Criterion


5.11.1 The Nyquist Criterion Using the Bode and Nichols Plots


5.11.2 Phase and Gain Margins

Chapter 6 Analysis of Non-linear Systems


6.1 Introduction to Non-linear Control


6.2 The Step Response Method


6.3 The Describing Function Method


6.3.1 Ideal Relay


6.3.2 Relay with Hysteresis h


6.4 Tsypkin's Method


6.4.1 Switching Conditions


6.4.2 Analysis of Steady Cycling


6.4.3 Constructing the Tsypkin Locus T(ω) from the Nyquist Locus L(jω)


6.4.4 Amplitude of the Oscillation


6.5 Comparison of the Three Methods

Bibliography

Problems

Appendix

Index