Recovering Waste Heat from Diesel Generator Exhaust; an Opportunity for Combined Heat and Power Generation in Remote Canadian Mines

Financial risks and environmental concerns associated with fossil fuel dependency are motivating mining companies to improve their energy profile. Diesel generators are vastly used as the main power source in off-grid mining operations located in the cold climate regions of Canada and other northern areas of the globe. However, almost 65% of the heat generated in the combustion chambers of a diesel generator is rejected as waste heat, a sizeable portion of which is discarded through the exhaust. This study presents a techno-economic analysis on the feasibility of recovering waste heat from exhaust streams of diesel generators by identifying their fuel consumption and recoverable thermal energy available in their exhaust. The potential energy and economic savings are investigated by reviewing the performance of the proposed diesel exhaust heat recovery system through a series of parametric studies, especially on temperature conditions, heat exchanger effectiveness, mine size and applications. The analysis shows that an extensive fraction of the heat demand of the mine could be supplied by the system. For pre-heating the mine intake air in cold climate regions, these savings could be as high as several millions of dollars. Consequently, the present work shows how deploying such diesel exhaust heat recovery strategy can lead remote mining towards a more energy efficient, economic and sustainable operation while gradually reducing carbon footprint in the life cycle of mines.