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Numerical and experimental investigation of mine exhaust heat recovery systems Kalantari, Hosein

Abstract

For underground mining operations in cold climates, such as Canada and Arctic regions, mine intake air heating is a significant energy- and carbon-intensive activity. The high thermal energy demand is commonly met by burning fossil fuels, particularly for mining operations in remote locations with limited grid access. This dependence on fossil fuels not only has an adverse environmental impact, but also incurs high costs. Mining companies are also facing increased pressure from society, investors, and the governments to address their carbon footprint. To overcome this energy–environmental challenge, mining companies are exploring innovative solutions for decarbonizing their operations. One potential solution is the implementation of a mine exhaust heat recovery system for intake air heating. This approach can reduce the high energy reliance of underground mine heating systems. In this study, two different mine exhaust heat recovery systems are proposed - an indirect capture-indirect delivery system and a direct capture-indirect delivery system - and their performances are evaluated using numerical models. Two fully-coupled thermodynamic models are developed to assess the potential economic and environmental implications of the proposed heat recovery systems. Furthermore, to evaluate the direct capture-indirect delivery system, two numerical models with different one-dimensional and three-dimensional approaches are developed to examine the performance of the direct heat capture unit under various design and operational conditions and to determine its ideal configuration for heat recovery applications. An experimental test setup is also designed and constructed to verify the concept of such heat exchanging systems at a lab scale and validate the results of the numerical models. Once the ideal design is identified, the developed thermodynamic code is populated with the operating and climate data from the mining operation being studied. This allows for the calculation of the potential cost savings and carbon emission reduction. The results of the study show that although both proposed heat recovery systems help mitigating the economic-environmental problem of mine intake air heating, the direct heat recovery system is found to be more efficient in terms of both carbon footprint reduction and energy cost savings.

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Attribution-NonCommercial-NoDerivatives 4.0 International