Date of Award

6-2011

Document Type

Open Access

Degree Name

Bachelor of Science

Department

Mechanical Engineering

First Advisor

Ann Anderson

Language

English

Keywords

thermal dynamics, heat source, geothermal energy, power, heat transfer

Abstract

This study investigates the difference in thermal efficiencies of horizontal ground source heat pump layouts through computer simulation and experimental modeling. The main objective of this project was to determine if the shape of the layout affects the total heat exchange in a horizontal geothermal system. Geothermal energy is power extracted from the Earth and studies have been focused on increasing the efficiency of the heat transfer from the Earth to the system. Steady state and transient thermal analyses were conducted on two horizontal layout shapes, a U-loop and a coil, in ANSYS Fluent. This system was not full size, both of the layouts were about 2.1 meters in length. The steady state analyses show that the coil shape is more efficient with a steady state heat transfer rate of 8.3 W, compared to 7.5 W produced by the U-loop. A transient simulation was also conducted for each layout and the results were dependent upon initial conditions. Setting different initial conditions to the soil and the working fluid resulted in slightly higher heat transfer rates initially. An experimental model of the coil layout was constructed and the results were compared to the results of the ANSYS simulations. The results from the experimental testing were inconclusive. However, for the conditions tested in the computational analyses, the coil shape produced more heat transfer than the U-loop shape, indicating that the shape of the layout does affect the total heat transfer, due to carry over heating through the soil.

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