Document Type



Master of Science (MS)


Mechanical Engineering

First Advisor's Name

Dr. Cheng-Xian Lin

First Advisor's Committee Title

committee chair

Second Advisor's Name

Dr. Yiding Cao

Second Advisor's Committee Title

committee member

Third Advisor's Name

Dr. Lu Zhang

Third Advisor's Committee Title

committee member


Borehole Heat Exchanger, conjugate heat transfer, computational power, mesh sizes, turbulence models, polyhedral, hexahedral, refinement, residence time, trapezoidal

Date of Defense



The primary purpose of this thesis was to develop a design for improving the efficiency of the vertical type single u-tube borehole heat exchanger. A thorough literature review of the various existing analytical and numerical models of the borehole heat exchanger (BHEs) was performed and numerical modeling of the BHE was conducted to solve the conjugate heat transfer problem in the BHE in 3D using ANSYS Fluent 2019 R1. A comparison between the results obtained using various mesh sizes, types, different turbulence models showed the independence of the parameters on the numerical simulation results.

From the numerical simulation, it was evident that the outlet temperature of the fluid was dependent upon the residence time of the fluid inside the pipe. Keeping this in mind, a design change incorporating the addition of trapezoidal finned casing between the grout and the domain has been proposed to enhance the efficiency of the BHE. On performing numerical simulations, it was seen that the addition of fins improved the heat transfer characteristics of the BHE, thus proving the hypothesis to be true.





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