TABLE OF CONTENTS A heating, ventilating, and air conditioning (HVAC) system is designed to satisfy the environmental requirements of comfort or a process, in a specific building or portion of a building and in a particular geographic locale. Designers must understand a great deal beyond basic HVAC system design and the outdoor climate. They must also understand the process or the comfort requirements.
In addition, designers must understand how the building is (or will be) constructed and whether that construction is suitable for the stipulated use of the space. For example, a warehouse cannot be used as a clean room without a great many modifications and improvements; to attempt to air-condition it to clean-room specifications without making the necessary architectural and structural revisions would be futile. While most examples are more subtle than this, many HVAC systems do not perform satisfactorily because the basic building is unsuitable. Designers must be able to recognize this.
It is also necessary to understand the use of the building and in most buildings the use of each part. How does this use affect occupancy, activity level, humidity, temperature, and ventilation requirements? Designers must have answers to these and many other questions before they can design a suitable HVAC system.
Comfort is a highly subjective word, reflecting sensations which vary greatly from one individual to another. Comfort can be defined only in general or statistical terms. Research by ASHRAE over many years has identified the major factors contributing to comfort: temperature, relative...
