Abstract
Opportunities exist to utilize rock aggregate to condition ventilation air at mine sites in humid continental climates. Vale's Creighton mine in Canada proved that a natural heat exchanger offered significant energy savings; however, the system was not suitable to establish design guidelines. A novel prototype-scale outdoor 30 m~3 rock pile heat exchanger experiment was constructed to characterize the thermal response to measurable aggregate parameters with insight shared regarding their sensitivity. This paper validates an unsteady 3D CFD numerical methodology involving the thermal non-equilibrium porous zone model with lab-scale-derived correlations against weather-influenced temperature data and proposes guidelines for improving performance: Increasing pile flatness was beneficial for damping whereas increasing hemispericality was beneficial for phase shifting. A CFD case study requiring 47 m~3/s (100,000 cfm) ventilation flow found that a rock pile constructed using traditional methods could achieve 100% damping with 6,000 m~3 of granitic rock aggregate at a pressure penalty of 2,500 Pa.
NSTL
Elsevier