Potential and Feasibility Study of Sewer Based Heat Recovery Energy Systems for Urban University Campus in Cold Climates

Wastewater is an abundant yet underutilized source of thermal energy. Integrating wastewater flow with heat exchangers and heat pumps is a promising method for addressing buildings' heating and cooling requirements. This approach not only enhances energy efficiency but also promotes sustainability in buildings. This study explores the techno-economic and environmental potential of such a system, known as a Wastewater Energy Transfer (WET) system. An energy model was developed to simulate and compare the performance of a WET system with an existing conventional Heating, Ventilation and Air Conditioning (HVAC) system. Using local greenhouse gas (GHG) emissions factors, utility rates, and weather data, the model calculated both systems' comparative energy consumption, operating costs, and GHG emissions. The models were created to determine the project's economic and environmental viability. Toronto Metropolitan University (formerly Ryerson University) campus buildings were utilized for a case study and implementation of a WET system. The analysis included six Canadian cities of Halifax, Montreal, Toronto, Winnipeg, Calgary, and Vancouver, with varying climates and energy infrastructures. Montreal had the highest operating cost savings at $2,057,855, while Calgary had the lowest at $128,544. Winnipeg led in GHG reductions, offsetting 5,464 tonnes annually, whereas Montreal had the smallest reduction at 21 tonnes.