Introduction; Abbreviations - Honeywell AUTOMATIC CONTROL SI Edition Engineering Manual

INTRODUCTION

This section describes control applications for air handling
systems commonly found in commercial buildings. The basic
processes such as heating, cooling, humidification,
dehumidification, and ventilation are presented individually then
combined into typical air handling systems. A discussion covering
requirements for effective control is also included to provide
guidelines for the design of the actual air handling systems with
the related controls. Examples are based upon digital control
systems. These digital control strategies may not be practical with
other forms of control, and may not be possible with all digital
controllers or by all digital controller programmers.

ABBREVIATIONS

The following abbreviations are used throughout this section
in the text and drawings. Refer to Definitions in the Control
Fundamentals section and the Psychrometric Chart
Fundamentals section for further details.
AHU — Air Handling Unit
BCMS — Building Control Management System
C — Celsius
DB — Dry Bulb
DDC — Direct Digital Control
DP — Dew Point
EA — Exhaust Air
EPID — Enhanced PID
IAQ — Indoor Air Quality
L/s — Liters per second
1
Applies to valves and dampers that are actuated to fail in the closed position in the event of loss of motive force.
2 Applies to valves and dampers that are actuated to fail in the open position in the event of loss of motive force.
ENGINEERING MANUAL OF AUTOMATIC CONTROL
AIR HANDLING SYSTEM CONTROL APPLICATIONS
Also throughout the section, dashed lines indicate interlocked
links and solid lines functional relationships between control items.
Psychrometric aspects are included for most applications.
They are shown in abbreviated form. Unabridged copies of
ASHRAE Psychrometric Charts No. 1 and No. 2 are included
at the end of this section for reference. For further understanding
of the basics of psychrometric charts refer to the Psychrometric
Chart Fundamentals section.
For additional detailed information on air handling systems,
refer to the ASHRAE 1996 HVAC Systems and Equipment
Handbook.
MA — Mixed Air
MAT — Mixed Air Temperature
1
N.C. — Normally Closed
2
N.O. — Normally Open
OA — Outdoor Air
OAT — Outdoor Air Temperature
P — Proportional
PI — Proportional-Integral
PID — Proportional-Integral-Derivative
RA — Return Air
RAT — Return Air Temperature
RH — Relative Humidity
SA — Supply Air
VAV — Variable Air Volume
WB — Wet Bulb
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