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Project At-a-Glance:
The opportunity: Working together with the University Health Network’s Toronto Western Hospital and sustainable energy leader Noventa® Energy Partners, Trane® helps implement the world’s largest wastewater thermal energy project.
The solution: A custom designed and engineered heat pump system including:
Trane® chiller heat pumps containing ultra-low global warming potential (GWP) refrigerants – Agility HDWA, CenTraVac CVHH, RTWDTrane system controls, including enterprise building management system Tracer® Ensemble with integrated work order managementTrane Digital Services including Intelligent Services, Analytics and active alarm monitoring
Sustainability outcomes:
Low-carbon energy powers 90% of the HVAC needs of a 1.5 million square-foot hospital campusCarbon emissions reduction of 8,400 metric tons/yearWater use reduction of 45 million litres/year1.8 billion kilowatt-hours of low-carbon energy over the life of the project19 megawatts of low-carbon thermal energy capacityOver 2,400 tons of low-carbon cooling capacityOver 33,000 MBTU of low-carbon heating capacity
University Health Network’s (UHN) Toronto Western Hospital in Toronto, Canada, has been a leader in sustainable practices for over twenty years. Guided by their motto “UHN: Practicing Patient and Planet Centred Care,” UHN has won multiple awards for innovative programming that incorporates care for the planet into their patient care model.
As a further step on the path toward sustainability, Toronto Western hoped to reduce energy use and carbon emissions. To help the hospital realize that goal, UHN tapped renewable energy leader Noventa Energy Partners, famous for their groundbreaking Wastewater Energy TransferTM, or WET® technology, to take advantage of thermal energy from the city’s municipal sewage system to heat and cool their campus.
WET technology replaces conventional heating and cooling systems with a heat transfer process based on recovering thermal energy from wastewater. Whereas most hospitals rely on greenhouse gas-emitting natural gas combustion to heat their facilities, the thermal energy contained in wastewater is low-carbon, highly reliable and renewable energy.
Though most people don’t ever think about it, wastewater contains abundant thermal energy. It represents a potentially massive unused resource that only requires the will — and the expertise — to make good use of it.
Assembling the decarbonization A-Team
As remarkable as a WET system is, it doesn’t function on its own. It requires a heat pump as a connection point between the wastewater system and the hospital’s HVAC. Noventa looked to Trane® for that critical link. For the system to make financial sense, the heat pump must be extremely efficient.
Another key reason Noventa chooses Trane for these large-scale projects is the depth of knowledge and capability in Trane engineering equipment and automation solutions and the quality and efficiency of the products. The expertise at Trane and the knowledge to successfully execute large and complex building automation and controls projects while integrating them into existing hospital systems allowed for efficient construction. Implementing the WET solution required working with the hospital without disrupting operations and ongoing coordination with local utilities and the City of Toronto.
The WET technology system connects directly to Toronto’s sewer system, which remains at a stable temperature throughout the year. The system removes solids from wastewater at the sewer level, then a self-cleaning heat exchanger eliminates the need to handle wastewater inside the buildings. To integrate the recovered thermal energy into the existing HVAC system, a highly efficient, high-temperature capable heat pump is required.
In summer, the system employs Trane chiller heat pumps containing ultra-low global warming potential (GWP) refrigerants that reject heat into the sewers. The result: the building is cooled without the need for cooling towers, which would otherwise consume energy and potable water. In winter, heat is extracted from the sewer system, and Trane chiller heat pumps supply the hospital with reliable hot water.
In addition to the heat pumps, the system leverages Trane system controls, including a Trane Tracer® Ensemble, enterprise-wide building management system, valves and meters to control and maximize system operation. Analytics and fault detection diagnostics built into the Trane automation system manage the equipment’s performance under various conditions to ensure a reliable energy supply.
Results
At 19 megawatts, Toronto Western’s WET system is currently the world’s largest raw wastewater energy project. The system is capable of supplying 1.8 billion kilowatt-hours of energy, over 2,400 tons of cooling, and over 33,000 MBH of heating.
The WET system will supply 90 percent of the energy needed to heat and cool the hospital’s 1.5 million square foot campus. In total, it eliminates 8,400 metric tons of carbon emissions per year — the equivalent of the carbon output of 1,800 gasoline-powered cars.
“We’re honored to partner with Noventa for Toronto Western Hospital to pursue their mission of practicing patient and planet-centered care,” said Lukas Glaspell, Trane Account Executive. “As a purpose-driven organization ourselves, we know that human and planetary health are closely linked. Alongside Noventa, we’re proud to support clients like Toronto Western in improving both.”