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Designing Successful HVAC System Through Controls
Lee Tapper, P.E., CIAQP,
LEED® AP, Holabird & Root, LLC
There are many projects with great design ideas and intentions,
the benefit of which never materialize. These failures are largely
due to controls. The importance of designing the controls
system for a science and research facility cannot be overstated.
The HVAC design engineer must not think of the HVAC system in terms
of the design capacity. To size the equipment, the engineer uses
the worst case operating condition, for winter and summer, both
with building use and weather. These are static conditions, and
the building will operate between these two extremes 99 percent
of the time. The HVAC control system allows the HVAC system to become
dynamic in nature, or "come alive."
The ability of the HVAC design engineer to effectively manage how
the system is going to operate during 99 percent of the time is
directly related to his/her understanding of control systems, design
of the HVAC control system, and clear control sequences. Unfortunately,
the HVAC design engineers do not take the time to write or understand
the control sequences for the systems and are relying on the installing
controls contractor and programmer to complete the design of the
control system. This is the single largest problem with the design
and construction of facilities today. The benefits of well-written
control sequences are:
- The owners' maintenance staff will be able to understand how
the system is to function and can offer valuable insight to the
HVAC design engineer during design.
- The control system programmer will understand the design intent
and be able to help refine (value add) the design as opposed to
just making it work.
- The building commissioning agent will have the ability to write
sound measurement and verification plans based on the sequence.
Although the controls technology that is currently available is
fantastic, the HVAC design engineer must be able to effectively
understand and communicate the design intent to control how the
system is going to operate at partial load conditions. The facility
is at partial load condition 99 percent of the time.
Labs21 Connection:
Throughout the presentation, examples of projects will illustrate
the validity of topics discussed. This approach has been used successfully
in over 13 research facilities over the past 10 years, which are
all in operation and would achieve a high rating using the LEED
criteria of the HVAC system. This was proved by Central College
Vermeer Science Center in Pella, Iowa, receiving a silver rating,
and by the fact that Grinnell College Conard Environmental Research
Area in Grinnell, Iowa, is seeking a gold rating. Effective, efficient,
reliable and safe HVAC system solutions are built on a sound design
approach and engineering practice, which engages and involves the
owner, and facilities personnel and is the backbone of sustainable
design. The presentation will review successful design procedures
to use the development of the HVAC controls design to act as a vehicle
to enhance the communication between the facilities personnel and
the HVAC designer. This also allows the facilities personnel to
engage in the project much earlier and facilitate the hand-off of
design intent, and the maintenance personnel to understand how the
HVAC system is to operate. Sustainability and maintainability are
blood brothers. Great ideas are only as good as they operate in
reality. Controls make them work as intended and Maintenance personnel
keep them operating effectively. The HVAC designer must understand
and design the controls system, and not leave it for the controls
contractor to try and figure out in the field.
Biography:
Lee Tapper, P.E., CIAQP, LEED AP,
is the Director of Engineering at Holabird & Root, LLC. As the
Lead Mechanical System Designer (both HVAC and Plumbing) on numerous
multidiscipline science and research facilities, he has designed
mechanical systems for a variety of laboratory types and conditions.
The laboratory types include instructional, research, and production
laboratory facilities for chemistry, physics, biology, biomedical,
psychology, neurology, and genetics. The project experience is a
combination of renovation, addition, and new. These types of projects
require developing an assortment of energy conservation strategies
to address the contaminate containment and operational character
that integrate into the building fabric to address personnel safety,
research flexibility, operational consistency, and energy stewardship.
This necessitates development of testing and modeling methods to
verify appropriateness of the design solutions.
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