- Author
-
Fang, J. B.
- Title
- Quantification of Heat Losses Through Structural Supports for Shallow Trench Heat Distribution Systems.
- Coporate
- National Institute of Standards and Technology, Gaithersburg, MD
- Sponsor
- Army Corps of Engineers, Washington, DC
Naval Facilities Engineering Command, Alexandria, VA
Air Force Engineering and Services, Boiling AFB, DC
- Report
-
NISTIR 89-4134,
October 1989,
107 p.
- Distribution
- Available from National Technical Information Service
- Keywords
-
shallow trench
|
heat loss
|
computer programs
|
heating
|
cooling
|
finite element method
|
heat transfer
|
pipe support system
|
underground heat distribution system
- Abstract
- Shallow trench heat distribution systems generally contain numerous structural supports, which are often in direct contact with hot carrier pipes, form highly conductive heat flow paths, and are major sources of heat loss. Quantification of the heat loss caused by thermal bridges due to pipe supports and prediction of temperature distributions were achieved by using three finite element computer models. The models considered the two-dimensional, steady-state heat conduction within a rectangular concrete trench containing two insulated pipes with and without pipe supports and the surrounding earth. The theoretical basis, computational scheme, and the data input and outputs of the developed computer programs for sample calculations are described. The two trench pipe support systems studied used horizontal anchoring and vertical supports. The rate of heat loss at the pipe section with structural supports is approximately 17 times greater than at the section without pipe supports. For typical support spacings, slightly more than one half of the total heat loss from the pipes occurs at the supports.