Print this page Variable Air Volume Systems - Principles, Applications & Acceptance Testing
A. Bhatia, B.E.
Course Outline
Air conditioning
systems can be categorized according to the means by which the controllable
cooling is accomplished in the conditioned space. The design of air distribution
system must combine a proper choice of engineered products efficiently providing
conditioned air to the space while low on energy consumption and with the ability
to provide individual control.
This 4-hr course
discusses the HVAC air distribution system with focus on Variable Air Volume
(VAV) systems. The course is entirely based on US Corps of Engineers Construction
Engineering Research Laboratory (USACERL) technical report 99:20, May 1999.
This course lists the Appendix A of the report and other appendices have been
separately listed.
The course includes a multiple-choice quiz at the end, which is designed to
enhance the understanding of the course materials.
At the conclusion of this course, the student will:
- Understand how the VAV system operates with its advantages and limitations;
- Learn the different classifications of VAV systems including pressure dependent, pressure independent and volume limiting boxes;
- Understand basic type of fans used in air handling systems including forward curved, backward curved, radial and aerofoil construction;
- Understand fan laws, fan sizing , fan curves and system curves;
- Understand different means to control the fan capacity;
- Learn different type of cooling coils including face split, vertical split and interwined coils;
- Understand different approaches to duct design;
- Learn different duct design methods;
- Understand different types of VAV terminal boxes;
- Understand VAV controls including direct digital controls;
- Learn about the instruments used in acceptance testing and monitoring; and
- Understand the
initial and final steps to testing, adjusting and balancing for performance
verification.
Intended Audience
This course is aimed at beginners, novice engineers, building services design engineers, end users, service technicians, architects, maintenance supervisors, contractors, energy auditors, layout professionals and general audience.
Course Introduction
Countless instances are occurring where building owners are upset about the performance of the HVAC system in a part or in all of their building or buildings, and rightfully so. They complain about discomfort, air quality concerns, inability to control their systems, lack of understanding how the systems are supposed to operate, displeasure with the amount of time their maintenance staff must spend to address apparent comfort problems or complaints from occupants. These issues quickly transfer to the design problems and the investigation and resolution of theses issues because owners automatically assume the problems are design related.
Course Content
In this course, you are required to study the US Army Corps of Engineers Construction Engineering Research Laboratory (USACERL) technical report 99:20, May 1999 Appendix A.
You need to open or download above document to study this course.
The HVAC equipment
configuration and variants available in the market today provides many options.
If conditioning is transferred only by means of heated or cooled air, the system
is termed an all-air system. If conditioning is transferred only by means of
hot or chilled water, the system is termed an all-water system. If conditioning
is transferred by a combination of heated/cooled air and hot/chilled water,
then the system is termed an air-water system.
Further the systems are classified as single zone, multi-zone, reheat, constant
volume or variable volume systems. In a constant volume system the volume of
air is held constant while the temperature is varied to meet the changing load
conditions. In a VAV system, the volume of constant temperature air modulates
to meet the changing load conditions. The popularity of VAV systems has grown
rapidly due to their ability to save large amounts of heating, cooling and fan
energy when compared to other HVAC systems.
Acceptance testing of a new facility's VAV system can be an important step in
ensuring the systems correct and energy efficient operation. The testing, adjusting,
and balancing (TAB) subcontractor documents his work in a TAB report, which
includes the data collected during TAB, as well as the air flows, fluid flows,
temperatures, etc. established for the system. Upon completion of TAB, the report
is submitted to the building owner/representative for review and approval.
A good understanding of the Variable Air Volume (VAV) systems is essential for
HVAC designer to meet the needs of current fast track projects and at the same
time ensure that the building gets the environmental system that will best fit
its needs.
Quiz
Once you finish studying the above course content, you need to take a quiz to obtain the PDH credits.
DISCLAIMER: The materials contained in the online course are not intended as a representation or warranty on the part of PDH Center or any other person/organization named herein. The materials are for general information only. They are not a substitute for competent professional advice. Application of this information to a specific project should be reviewed by a registered architect and/or professional engineer/surveyor. Anyone making use of the information set forth herein does so at their own risk and assumes any and all resulting liability arising therefrom.
