The UBC Okanagan campus in north Kelowna – photo by Martin Dee
UBC Reports | Vol. 51 | No. 11 | Nov. 3, 2005
Vast aquifer below Kelowna campus provides more sustainable heating options
By Bud Mortenson
Groundwater will be used to heat and cool $400 million worth of new buildings planned for the UBC Okanagan campus in Kelowna, with the promise of major benefits for the local environment.
Technology known as groundwater geo-exchange will eventually replace the existing natural gas plant, which is nearing the end of its lifespan. Built to heat and cool today’s 500,000 square feet of building space, the current conventional plant lacks capacity to service an additional one million square feet of space on the Campus Master Plan drawing board. Turning to a natural resource in plentiful supply under the campus presented a great option.
“It’s a huge win-win for the environment and for the University,” says Aidan Kiernan, Associate Vice President of Operations at UBC Okanagan.
“Over a 20-year period, a groundwater heat exchange system will prevent 38,000 tonnes of carbon dioxide emissions into the atmosphere,” he says. “That’s equivalent to taking 8,000 cars off the road, or planting 18,000 acres of fruit trees or vineyards — four times the current vine-producing land in the Okanagan.”
The concept is relatively simple: pump 10.5°C (51°F) water out of a natural underground water body — known as an aquifer — and compress it in winter months to raise the temperature to about 54°C (130°F) to heat buildings, or use it for cooling in the long, hot Okanagan summers.
“Then we’ll put it all back into the aquifer,” says Kiernan. “That’s the important thing, to put the water back. We will ensure our impact on the environment is minimized. We have to walk the walk, not just talk the talk.”
Heating and cooling with groundwater will save a bundle in energy costs. Although building the geo-exchange system will cost $6 million — about $1 million more than a conventional gas-fired heating plant — it is expected to save at least $100,000 a year in energy costs.
Kiernan has a history of seeking ways to apply alternative energy systems. He introduced a seawater heat exchange system for the marine science facility when he worked at Memorial University in Newfoundland. At the former Okanagan University College’s KLO Road Campus in south Kelowna he devised a system that captures heat from the City of Kelowna’s neighbouring wastewater treatment plant.
Bringing that experience to UBC Okanagan, Kiernan has been working with engineers and hydrogeologists for the past year to explore a geo-exchange system for the campus. “The analysis was that we are sitting on a gold mine,” says Kiernan.
The campus happens to sit directly above two extremely desirable geological features: a vast aquifer with a year-round temperature of about 10.5°C, and a 75-metre (250-foot) thick gravel bed that will allow groundwater to be pumped up and put back where it came from, with virtually no measurable impact on the aquifer’s volume or pressure.
“It truly is exactly what you look for in an aquifer to support an open loop for groundwater exchange,” says Kevin Rafferty, an Oregon-based geo-exchange consultant on the UBC Okanagan project. “You want to see the ability of the aquifer to produce and accept a large flow of water.”
Taking water out of the aquifer is one thing. It’s another thing to get the water back in. That’s where the enormous gravel deposit comes into play. It has the capacity to receive water from either pressurized injection wells or a rapid infiltration lagoon that would allow water to percolate back into the ground.
A veteran of geo-exchange projects from Florida to the Yukon, Rafferty says tapping into groundwater is an energy-saving option that’s often overlooked. “There are lots of places where people have the nuts and bolts to do this, and they don’t do it. They don’t have the vision,” he explains.
Sustainability is part of the UBC Okanagan Academic Plan, and it’s being built into operational plans. Kiernan notes that he has been working with the UBC Campus Sustainability Office in Vancouver to establish a comprehensive program that will include recycling and selecting environmentally sustainable cleaning products, paint, building materials — even office furniture. And, passive solar heating is being considered to help meet peak hot water demands in two new residence buildings already under construction.
The first buildings to go online with geo-exchange heating will be a new multipurpose building in May 2007, and the Engineering and Management building in September 2007.
“We will provide geo-exchange technology for all new construction on campus and see if existing buildings can be retrofitted later,” Kiernan says. “We think this will receive worldwide attention — that we will be the go-to place to see how to do it.”