Control Systems for Heating, Ventilating and Air Conditioning, Sixth Edition is complete and covers both hardware control systems and modern control technology. The material is presented without bias and without prejudice toward particular hardware or software. Readers with an engineering degree will be reminded of the psychrometric processes associated with heating and air conditioning as they learn of the various controls schemes used in the variety of heating and air conditioning system types they will encountered in the field. Maintenance technicians will also find the book useful because it describes various control hardware and control strategies that were used in the past and are prevalent in most existing heating and air conditioning systems. Designers of new systems will find the fundamentals described in this book to be a useful starting point, and they will also benefit from descriptions of new digital technologies and energy management systems. This technology is found in modern building HVAC system designs.

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.

In the First Edition of this classic text, Roger Haines devised a simple building-block method which enabled students to quickly learn about the operating principles and applications of all the basic devices and subsystems used in HVAC control. The new Fifth Edition, completely revised by Douglas Hittle, takes into account the many technological changes that have arisen since then. Crystal-clear guidelines on combining control devices, circuits, computers, and HVAC equipment into efficient control systems that are accurate and energy-efficient are presented along with hundreds of charts and illustrations which provide data critical to the understanding and design of modern HVAC systems. These include: psychrometric charts and tables relating to optimal levels of temperature and humidity at specific altitudes: block/flow diagrams which show control component function; circuit diagrams of important electrical control system components; schematic diagrams showing the configuration of various control systems.

This handbook was written to serve as a complete and concise reference for those engaged in the operation and maintenance of automatic control systems serving building heating, ventilating and air conditioning systems.

Annotation This book provides a thorough introduction and a practical guide to the principles and characteristics of controls, and how to apply them in the use, selection, specification and design of control systems.

Heating, ventilation and air conditioning is a technology that is concerned with indoor and vehicular environmental comfort. Its objective is to provide comfort and high indoor air quality. The technology develops on the principles of fluid mechanics, thermodynamics and heat transfer. Ventilation involves exchanging air in any space in order to control temperature as well as remove odors, dust, airborne bacteria, carbon dioxide, etc. It can be achieved mechanically by using an air handler, mechanical exhausts or ceiling fans, or naturally using operable windows, louvers or trickle vents. In central heating, water, steam or air is heated using a boiler, furnace or heat pump, and the resultant heat is transferred by the processes of convection, radiation or conduction to the living spaces in a house or building. Air conditioning and refrigeration involves cooling and humidity control through the removal of heat using heat transfer processes. This book is a compilation of chapters that discuss the most vital concepts about the technology of heating, ventilation and air conditioning. Such selected concepts that redefine the understanding of the crucial aspects of this technology including its design, analysis and control systems have been presented herein. It will serve as a valuable reference guide for architects, interior designers, professionals and students involved in this area of study.