Prioritizing sustainability in the architecture, engineering and construction (AEC) industry often means finding innovative solutions to achieve client goals. And that is exactly what the PCL-Marco Group Joint Venture team at the Government of Newfoundland and Labrador and Newfoundland and Labrador Health Services’ new hospital in Corner Brook is doing.
Envisioned to enhance healthcare services in Newfoundland and Labrador with sustainable features and advanced technologies, the new hospital was designed with the intent to become an important civic landmark for the community. The seven-story hospital is targeting Leadership in Energy and Environmental Design (LEED®) v4 Silver certification and focuses on functional design that has a positive, long-term effect on occupants as well as the environment.
One of the groundbreaking achievements of this unique project is fittingly underground. Just 600 feet below the hospital’s parking lot lies a geothermal field that will make 100% ground source geothermal heating for the hospital possible – the first such solution of its kind for a healthcare facility in North America. This geothermal field is the largest geothermal heating and cooling system incorporated into a Canadian healthcare project to date and the third largest system nationwide. A geothermal system solution was purposefully chosen to help achieve significant energy reduction and operating cost savings across the hospital’s lifespan, with numerous considerations around making geothermal a viable solution for the project and site.
After evaluating many different building systems options and conducting an in-depth cost and energy efficiency analysis, PCL-Marco and our partners at Smith + Andersen and Geosource Energy Inc. arrived at an eco-friendly solution that is setting the stage for the future of sustainable construction in the healthcare sector.
To dive into the world of geothermal systems, we need to first understand geothermal energy. Geothermal energy comes from the depths of the Earth’s crust.
“Under the umbrella of geothermal energy are three different ways to extract the energy: geothermal power production, high temperature heating and geo-exchange,” describes Mike Deeward, engineering manager at Geosource Energy Inc. “While the former two require steam or hot water, the latter needs consistent ambient temperature. Geo-exchange is an electrified, low carbon method to heat and cool.”
How does a geo-exchange system work? The first step is to identify the geo-exchange field – the area of the earth that holds high heat flow. Then, a closed loop system of piping is buried into the field to transfer heat to and from the ground. With a depth of up to 600 feet, 375 vertical bore holes were drilled into the field for the loop system installation.
“At the new hospital, the geo-exchange field stretches up to 96,000 feet wide which is approximately the size of 1.7 NFL football fields,” explains Peter Kastelic, principal at Smith + Andersen, the mechanical and electrical design engineers for the project. “The loop system itself utilizes approximately half a million linear feet of piping. If you stretched out the piping, it would extend three times the distance between Corner Brook and Deer Lake. This speaks to the sheer size of not only the field but also the hospital. The system is supporting a large facility and it was designed accordingly”
Once the horizontal piping is installed to connect a series of geo-exchange wells, the lines are pressure tested. Each line is tested to ensure a PSI of 100 for a duration of at least 24 hours. Once the correct pressure level has been met, the lines are flushed to remove debris before pumping an antifreeze water solution through the closed loop system. This process creates cooling and heating through refrigeration cycles.
With a breathtaking view of the ocean and enriched history, Corner Brook, Newfoundland and Labrador is definitely a sight to see. However, the region’s rugged terrain and extreme weather presented some challenges to construction. Accommodating the unique contractual considerations that came with building in this location was the team’s first hurdle.
During the pursuit phase of the hospital, one of the project requirements was that the use of fossil fuels was prohibited for heating. For a project of this size, fuel delivery and storage were the deciding factors to eliminate the use of fossil fuels for the hospital.
With the lack of natural gas pipelines or utility infrastructure in Newfoundland, the typical approach to heating in the region is electric resistance heating using electric fired boilers. However, the use of electricity also became a challenge during the planning process.
Newfoundland Power, the province’s utility provider, has a maximum feeder capacity of 13 Mega Volt amp (MVa). However, If PCL-Marco chose to use electric boilers, the power capacity would be over this amount, which would necessitate the construction of a new substation on the site. This would in turn increase the overall cost of the project. Additionally, the team was striving to create the most energy-efficient design while achieving LEED® v4 Silver requirements and a geothermal system played a role in achieving that.
“Our design needed to guarantee high energy performance of the building for the next 30 years,” says Shaun Blore, PCL Toronto district building systems manager. “A geo-exchange system looked like a clear choice that would reduce the project’s net present value (NPV) while keeping our consortia competitive.”
Before landing on the final method, PCL/Marco needed reassurance of the energy and cost efficiency of using a geo-exchange system. Conducting an initial NPV analysis helped to understand the cost considerations of a geothermal system and guided the team during the design process.
“While the results of our NPV analysis revealed that the initial up-front costs of the geo-exchange plant was approximately 30-35% higher than the traditional fossil fuel fired plants, operational costs for the traditional plant were higher. Without energy costs considered, the geothermal plant solution warranted a 20% premium,” says Blore. “The geo-exchange solution provided an expected annual energy savings premium of 15-20%. That combined with operation expenditure savings over the life span of 30 years yields approximately 12% total cost savings. The savings would only continue to grow over time, making the geo-exchange solution the best financial choice for the project.”
While the geo-exchange system proved to be cost saving, its thermal efficiency is just as incomparable. Air source and ground source heat pump systems, using the air or ground to reject and absorb heat, have more than double the thermal efficiency than a modern gas heating system and an electrical resistance heating system. It was evident that a geo-exchange system was the ideal low-energy, low-emission solution.
The impact of the geo-exchange system goes beyond energy consumption, demand and operating costs. This system also had a significant influence on the overall design of the hospital which, in turn, will have a positive impact on additional operating costs.
“Because the need for roof-mounted cooling towers has been completely eliminated, the hospital’s geothermal system reduces the visual and acoustic impacts of heating and cooling to the facility,” explains Kastelic. “The system will also improve maintenance efficiency because all mechanical equipment is consolidated into a single mechanical room. The same source equipment is used for the heating and cooling which reduces the requirement for additional boilers.”
In turn, eliminating cooling towers allows the hospital to save up to two million gallons of water per year. That alone is equivalent to three Olympic-size swimming pools annually.
“As the first 100% geothermal healthcare facility in North America, the new hospital in Corner Brook demonstrates the importance of implementing energy efficient measures and sustainability best practices in building systems,” says Blore. “With the help of our expert consultants and partners, we will continue to model the way for a more sustainable future.”