CMX 2004 - Plumbing & HVAC

Cover Story
The UOIT well field. Uncapped well heads show up as black dots. Four-inch piping runs from the wells into the mechanical corridors that circle the field.
Scott Springfield (Calgary) air handlers
up-feed a series of medium velocity
duct risers on either side of the atria.
The duct risers connect to variable air
volume (VAV) terminal boxes, complete
with reheat coils. The office buildings
utilize VAV terminals to feed zoning
options partitioned within a raised
floor pressure cavity. Ventilation air is
supplied from the raised floor through
swirl-type floor diffusers.
This adds complexity to the building
design, but there’s a good reason for it.
“Under floor air delivery promotes
stratification, which reduces cooling
loads while enhancing natural ventilation
through buoyancy effects,”
explained Godawa.
Laboratory buildings also use VAV
terminals, but are designed with overhead
air distribution to minimize the
risk of contamination associated with
potential spillage of laboratory materials
into the raised floor cavity.
All air handlers feature four-inch
thick insulated walls. Each contains
heating and cooling coils along with an
ultrasonic humidifier.
Ultrasonic humidifiers turn water to
a ‘dry’ mist through high frequency
vibration. They have a couple of key
advantages, noted Bright. They supply
humidity instantly when turned on and
“they use a fraction of the energy of gasfired
humidifiers.”
All air handlers are designed with
Air handlers are built with efficiency and maintenance in mind.
maintenance in mind. They are well
lighted with wide doors and standing
room for a 6'2" maintenance worker.
There is a lifting railway to swing the
motor out. Windows are at eye level.
Coils are accessible on both sides for
cleaning. The air handlers are spaced far
enough apart that coils can be pulled
straight out.
The ventilation system is designed
with operable windows that allow some
level of natural ventilation and improve
control of indoor air quality. Atriums in
some buildings have been designed for
a green or breathing wall – that’s right,
with vegetation covering the wall – to
enhance indoor air quality.
Designed for efficiency
At UOIT, the mechanical system is only
part of the equation. Heating and cooling
loads are minimized through energy
efficient building design.
Walls are R-20. A green roof covers a
portion of each R-30 roof. Storm water
is retained on the roof(s) through the
natural retention of grass and soil. The
surplus runs off into an underground
storage cistern and is used for irrigation.
As well, each building has been
designed with a second plumbing system,
independent of the potable water
system, so that storm water can be used
for flushing sewage if necessary.
Windows, by Sunlite Insulating Glass
Manufacturing (Mississauga, Ont.), are
high efficiency R-9 with thermally broken
frames and no thermal bridging.
They incorporate HM-TC88 film and
are gas filled with krypton. This allowed
a significant savings in capital cost for
the perimeter heating system.
The payback
The high efficiency HVAC equipment
and geothermal well field at UOIT were
an expensive option. The biggest drawback
was the higher capital cost.
However, engineers have calculated
an energy savings of 40 per cent per year
in the heating mode and 16 per cent in
the cooling mode. The use of ground
source heating allowed a considerable
reduction in boiler plant capital cost.
The geothermal system has fewer moving
parts than a conventional cooling
tower system and therefore requires less
maintenance.
As well, there will be a reduction in
potable water and chemical use of six
million U.S. gallons per year.
Compared to a conventional heating/cooling
system, the payback on the
high efficiency HVAC equipment will
be three to five years and the payback
on the well field is estimated at seven
and a half years.
Increasing energy costs will make the
long-term savings to the university
substantial, reported Bright. This is
what sold university officials on the
project.
High efficiency condensing boilers provide trim heat.
Air handlers are equipped with ultrasonic
humidifiers.
The team
The architect for the new University
of Ontario Institute of Technology is
Diamond & Schmitt Architects Inc.
Keen Engineering Co. Ltd. of
Toronto was selected to do master
planning along with the design of the
HVAC, plumbing, fire protection
and automation systems for the eight
academic buildings and central
plant. Beatty & Associates, Toronto,
designed the geothermal field. In
early November, SDS Drilling Co. of
Calgary finished digging the geothermal
well field. Ground Heat Systems
of Toronto installed the geothermal
piping.
Mechanical contractors involved
in the project to date are Comstock
Canada, Mississauga, Ont., (Building
1), Urban Mechanical, Toronto
(Buildings 2 and 3), and George A.
Kelson & Co., Newmarket, Ont.
(Building 6). The general contractor
is Ellis Don Corp.
The controls contractor is Jet
Electric of Ajax, Ont. utilizing
Siemens controls.
(Editor’s note: This is not a comprehensive
list. Only the companies
that were involved in the mechanical
aspect of this project are named.)
www.plumbingandhvac.ca March/April 2004 – Plumbing & HVAC Product News 15