POWER September 2020 - 16

O&M
Geothermal Project Powers
Airport Expansion
Vancouver International Airport is the
largest facility in British Columbia and requires
a lot of heating and cooling. Those
needs will be increased by a $300 million
expansion designed to add 300,000
square feet to the terminal complex's already
spacious environs.
The airport is in the midst of a number
of capital construction projects, part of
the facility's multi-year expansion that will
see the airport complete 75 major projects,
totaling $9.1 billion over 20 years.
To help meet the power demands of the
expansion, and to also substantially limit
its environmental footprint, the airport
chose an eco-friendly geoexchange, or
ground source geothermal, system for
heating and cooling. The new Central Utilities
Building, still under construction, will
improve efficiency by centralizing all the
equipment needed to meet the airport's
heating, cooling, and electricity demands.
The airport's geothermal exchange
system project was recently honored
by the Plastics Pipe Institute Inc. (PPI).
PPI is the major North American trade
association representing all segments of
the plastic pipe industry. Canadian pipe
manufacturer Versaprofiles, the Quebecbased
company that provided the pipe
for the airport's geothermal exchange
system, received Project of the Year for
Building & Construction at PPI's virtual
annual meeting in May.
The geothermal system's design required
hundreds of vertical boreholes
(Figure 1) to provide sustainable heating
and cooling for the terminal and is one
of the largest geothermal energy projects
in Canadian history. Borehole drilling
and installation of the geothermal
loops and headers is complete, and the
67,000-square-foot Central Utilities Building
is expected to be operational by 2022.
This $350 million system is crucial to
the airport's objective to reduce greenhouse
gas emissions. It is expected to
substantially reduce CO2
emissions from
heating and cooling by 30% to 35%.
Heat pump-based geoexchange systems
can significantly flatten the electricity
grid's energy demand curve. They
also reduce dependence on fossil fuels
for heating and cooling, and are becoming
a leading technology in the electrification
of government and commercial
16
1. The Vancouver airport's system required
hundreds of vertical boreholes to provide
sustainable heating and cooling for the terminal.
It is one of the largest geothermal
energy projects in Canada. Courtesy: Plastics
Pipe Institute (PPI)
building infrastructure.
" PPI and our members promote the
adoption of geothermal technologies
to help reduce energy consumption for
heating and cooling buildings, saving
owners money, " said Lance MacNevin,
PE, director of engineering for PPI's
Building & Construction division. " Other
benefits of ground source systems are
better reliability and building resiliency,
with no exposed outdoor components.
Also, water-to-water heat pumps are a
perfect match for hydronic heating and
cooling distribution systems, which are
comfortable and efficient technologies
for use in residential and high-performance
commercial construction. "
MacNevin's group has established a
Geothermal Steering Committee to focus
support specifically on the geothermal
industry.
HDPE Piping Loops
Versaprofiles in 2019 signed an agreement
with Ground Source Energy, an
Alberta-based geothermal contractor, to
manufacture and supply the high-density
polyethylene (HDPE) geothermal piping
loops for the project. One of the main
challenges was to ship the geothermal
piping loops almost 3,000 miles across
Canada. Seventeen containers of pipes
left the production facility, traveling first
by truck, then by train to Vancouver.
Versaprofiles' contribution to the project
was 841 Verticaloop single U-bend
geothermal loops, each 1,000 feet long
with a molded and heat-fused U-bend
installed at the midpoint, for a total of
841,000 feet of HDPE geothermal piping.
The job used about 280,000 pounds
of resin and required the equivalent of
35 days of production capacity for the
www.powermag.com
company's Saint-Lazare-de Bellechasse,
Quebec, facility. The first geothermal
loops were installed in April 2019.
Tony Mooney, project manager at
Ground Source Energy, said one of the
most important considerations of geothermal
energy installations is ground
conditions. " The lithology, or rock characteristics,
needs to be of a high-enough
thermal conductivity to move energy
through the earth, " said Mooney. " In
this case, the soft glacial till overburden
provided wet soil conditions that are suitable
for heat transfer to occur.
" The glacial till affects the thermal
conductivity of the ground, which affects
the size of the system they need
to get the energy, and our drilling methodology, "
Mooney said. " We still put the
HDPE loop in the same way we do into
bedrock or for any other application or
system. How we make the hole and how
many holes needed depends on how the
earth varies. So, if it's sand, you typically
don't even put geo where there's sand,
but if you're in bedrock, heat moves well.
If you're in wet soil, the thermal conductivity
moves well, wherever heat can
transfer, and that determines how many
holes you need. So, if it was more sandy
and dry, it would be less conductive, and
you'd need more holes and more loops
to get the same amount of energy out of
the ground. "
He continued: " The only problem with
glacial till is that it isn't bedrock, " he said,
noting that means drilling with the casing
in each hole to keep the hole from
collapsing on itself. The pipe is then fed
into the hole from a spool.
" Because it's glacial
till, we used
sonic drilling and drilled with the casing,
because you can't use air rotary or other
methodologies because there is no
bedrock to keep the hole open, so you
have to have casing all the way down so
the hole stays open, so you can put the
loop in, " Mooney said. " We put the loop
in within the casing and then we grout
(Figure 2). We end up with a loop in the
ground surrounded with thermally enhanced
grout, and just normal earth. "
" The piping material is critical to the
overall success of geothermal systems, "
said David Fink, president of PPI, adding
that it " must provide corrosion and
chemical resistance, flexibility, long-term
toughness [impact resistance], pressure
capability, and temperature resistance.
POWER | September 2020
http://www.powermag.com
POWER September 2020

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