Date of Award

2018

Document Type

Open Access Dissertation

Degree Name

Doctor of Philosophy in Civil Engineering (PhD)

Administrative Home Department

Department of Civil and Environmental Engineering

Advisor 1

Zhen Liu

Committee Member 1

Stanley J. Vitton

Committee Member 2

Pengfei Xue

Committee Member 3

Kazuya Tajiri

Abstract

Geothermal energy recovery from flooded mines has been gaining momentum worldwide. Numerous mines are flooded after their closure, either naturally or artificially, in which the water in the mines can be heated by the surrounding geologic formations due to geothermal gradients, leading to sizeable man-made reservoirs of warm water. Such mine water, therefore, can be treated as a renewable geothermal resource for heating/cooling buildings, which has the potential to benefit over millions of people in the United States and much more around the world. Though some real projects and/or installations launched worldwide for the use of flooded mines for geothermal applications, there are many uncertainties in the theoretical aspect of this application, in particular, the scientific understanding of the large-scale natural mine water-geologic formation system is still in a preliminary stage and thus far lags behind its application.

Motived by this missing scientific linkage, the current dissertation presents an investigation with multiphysics analyses to understand the large-scale natural mine water-geologic formation system. The main objective is to provide an in-depth understanding of this system for guiding and optimizing this large-scale geothermal application from a scientific perspective. For the purpose, this dissertation presents four specific investigations.

The first investigation explores a specific site with comprehensive information relevant to the natural mine water-geologic formation system for recovering geothermal energy from deep abandoned mines for heating and cooling buildings.

The second investigation presents the results of field tests and multiphysics analysis of a flooded shaft for understanding the transport of heat and mass in the natural mine water-geologic formation system.

The third investigation addresses a key scientific issue regarding the layering phenomenon observed in large bodies of mine water, which controls the temperature distribution and heat energy storage in the deep geothermal field for the proposed energy renovation.

The fourth investigation aims to provide insights into the dominant heat and mass transport mechanisms underlying thermohaline stratifications and investigate the factors influencing thermohaline stratifications.

The above four investigations presented in this dissertation provide the urgently needed scientific understanding of the natural mine water-geologic formation system for this large-scale geothermal application, which eventually offers scientific bases for the future optimal design of this unique large-scale application of recovering geothermal energy from flooded mines.

Available for download on Friday, May 17, 2019

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