Simulation of Ground Coupled Vertical U-Tube Heat Exchangers

File(s)
Date
1997Author
Rottmayer, Steven P.
Publisher
University of Wisconsin-Madison
Metadata
Show full item recordAbstract
Ground coupled heat pumps are an efficient alternative to conventional methods of conditioning
homes, because instead of using the ambient air they utilize the ground as an energy source or sink.
However, ground coupled heat pumps have high installation costs that makes it critical to design the
system to maximize performance. Vertical u-tube heat exchangers are commonly used as the
ground coupled heat exchanger, but estimating their performance is difficult because of the unique
heat transfer conditions of this configuration.
This thesis focuses on modeling the vertical u-tube heat exchanger. Several initial attempts to model
the heat exchanger were made, and finally an explicit euler finite difference numerical technique was
employed. The ground storage volume is divided axially into sections, and each section is a two
dimensional cylindrical mesh representing the fluid, tubes, grout, and soil at a specific depth. The
tubes are approximated by non circular sections of the mesh, and is accurate to within 8%. A local
coupling factor can increase this accuracy to 3% for most systems, and comparisons with an existing
model showed good agreement. The finite difference model has provided an approach that is
fundamental and readily extended to more realistic conditions. It is accurate and fast enough to be
useful as both a comparison to existing models and as a design tool.
Subject
Thesis (M.S.)--University of Wisconsin--Madison, 1997.
Dissertations Academic Mechanical Engineering.
University of Wisconsin--Madison. College of Engineering.
Permanent Link
http://digital.library.wisc.edu/1793/7759Description
Under the supervision of Professors William Beckman and John Mitchell; 115pp.
Citation
Rottmayer, S.P. (1997). Simulation of Ground Coupled Vertical U-Tube Heat Exchangers. Master's Thesis, University of Wisconsin-Madison.