Reducing GHG Emissions Through Efficient Water Heating Technologies

In the residential sector, approximately 300 PJ per year of energy is used for water heating, equating 17 mega-tonnes of carbon dioxide emissions per year. Conventional tank-based gas-fired water heaters operate with a seasonal efficiency on the order of 60%. The potential exists to improve this efficiency to 75-85%, and perhaps even higher. With a 10% market share, the reductions in CO₂ emissions would be on the order of 0.4 Mt/y. The Integrated Energy Systems Laboratory (IES) of the Sustainable Built Environment Group at the CANMET Energy Technology Centre - Ottawa presents the results of efforts to date to validate and optimize the superior performance of instantaneous water heaters both through laboratory and field testing. In addition to performance figures, a variety of operational issues with respect to instantaneous water heaters will also be discussed. Some design improvements with respect to current storage and instantaneous water heater technologies will also be presented.