Transforming Toronto Western Hospital: Record-breaking Wastewater Energy Project

Challenge

Leaders at University Health Network’s (UHN) Toronto Western Hospital wanted to lower the hospital’s environmental impact, especially for heating and cooling its buildings, in alignment with UHN’s commitment to “patient and planet-centred care.”

Since conventional heating and cooling of buildings contributes nearly 30 percent of global energy-related carbon emissions¹, leaders needed an innovative solution. They were especially interested in utilizing the waste thermal energy available in the sewage system. While conventional heating and cooling systems either release greenhouse gases or use water to reject building heat into the ambient atmosphere, the latent energy of wastewater is carbon-free.

Heat for wastewater energy is readily available with over 168 billion litres of sewage dumped daily in North America². The hospital wanted to harness some of that energy, without interruptions to their operations or exposure to the wastewater. In their search for a partner, UHN was looking to use proven technology and work with a party that has demonstrated success in developing renewable energy projects.

Solution

In collaboration with the City of Toronto and Noventa Energy Partners, Toronto Western Hospital embarked on a record-breaking project to heat and cool their campus with energy from municipal sewage. Noventa, a renewable energy company, has partnered with Trane to build a Wastewater Energy Transfer™️ (WET™) system for the hospital in what is to become the world’s largest raw wastewater energy project.

The engineered solution will leverage Trane heat pumps, system controls, and analytics while managing equipment performance at various climatic conditions — for a reliable energy supply.

• For cooling, the project will use Trane chiller heat pumps with ultra-low global warming potential (GWP) refrigerant to reject heat into the sewer system in the summer without the need for cooling towers. Using cooling towers would consume energy for the fans and require important water resources.
• For heating, the project will extract the heat from the sewer system and boost the temperature using Trane chiller heat pumps to supply the hospital with reliable hot water.

In addition to providing the chiller heat pump equipment, Trane also enabled system controls with a Trane Tracer® Ensemble, enterprise-wide building management system, valves, and meters to control and maximize efficient system operation. Direct emissions will be eliminated by utilizing Trane energy management control and high-efficiency heat pumps, together with Noventa’s proprietary HUBER ThermWin® technology. This solution aligns with Trane Technologies’ sustainability values, including its Gigaton challenge commitment to reduce one gigaton (one billion metric tons) of GHG related to the use of its products by 2030.

Results

The Wastewater Energy Transfer™ system supplies 90 percent of the 1.5 million sq.ft. hospital’s heating and cooling needs and reduce carbon dioxide emissions by 8,400 tons a year. To put it into perspective, cutting 8,400 tons of carbon dioxide is the equivalent of taking more than 1,800 cars off the road each year.

The total energy supplied to the Hospital from the 19MW WET™ system will amount to 1.8 billion kilowatt-hours. The WET™ system has a capacity of over 2,400 tons of cooling and over 33,000 MBH of heating from the Trane heat pumps. The project, financed by Noventa, has received financial support from the Government of Canada’s Low Carbon Economy Fund and the Canada Infrastructure Bank.

“We look forward to implementing this record-breaking solution with Trane and our other partners to support UHN in their commitment to deliver a healthier world through a more sustainable environment. With a reduction of 8,400 tons of GHG emissions per year, this project will really play its part in creating that healthier world,” said Cam Quinn, Senior Project Manager at Noventa.

“This innovative solution aligns with our commitment to sustainability and patient- and planet-centered care, and we look forward to its positive impact,” said Ed Rubenstein, Director of Environmental Compliance, Energy, and Sustainability at UHN.

“We’re excited to be part of the team with Noventa implementing this collaborative effort,” said Lukas Glaspell, Account Manager for Trane. “This truly provides a true win-win for all involved — most importantly for the hospital and ultimately its patients and the planet.”

^{1 “Bringing embodied carbon upfront,” World Green Building Council, 2019 Report on Advancing Net Zero}

^{2 Noventa Energy Partners video}