Details:

Creators:
Nydahl, John ; Pell, Kynric ; Lee, Ron ; Sackos, John
Nydahl, John ; Pell, Kynric ; Lee, Ron ; Sackos, John Less -
Corporate Creators:
University of Wyoming
Corporate Contributors:
United States. Federal Highway Administration
Subject/TRT Terms:
[+]
Bridge Decks Bridge Design Bridges--Floors Bridges--Snow And Ice Control Cost Effectiveness Evaluation Heating-pipes Heat Pipes Snow And Ice Control
Publication/ Report Number:
FHWA-WY-84-001
Resource Type:
Tech Report
Geographical Coverage:
Wyoming
Edition:
Final report.
Corporate Publisher:
Wyoming. State Highway Department
Abstract:
The design, construction, performance and analysis of the first ground heat pipe

system to heat an entire bridge deck are detailed. Each of the sixty heat pipes in

this system is comprised of a 6 em (2.4") diameter, 31 m (lOO')_long vertical ground

evaporator, and a condenser that was forme~ by manifolding 2.5-cm (1") pipe on 15 ~m

(6") centers to heat 7.6 m2 (82 ft2 ) of deck surface. Ammonia vaporizes in an

evaporator anytime the encompassing ground is warmer than the bridge deck, and this

vapor ascends into the condenser section where it releases its heat of vaporization

to the deck.

The integration of the heat pipes into the bridge deck did not have a

significant impact on the bridge construction. The heat pipes increased the deck's

weekly averaged surface temperature up to l0°C (l8°F), preventing preferential

freezing of the deck relative to the adjacent road. Sno:w cover duration was decreased·

by 50% despite a ground temperature of only soc (46°F). The m~n~mum dynamic

conductance of this system during major heating events appears to be between 8 and 11

watts per m2 of deck per oc temperature difference between the far-field ground and

the deck surface. A thermal model was developed to accurately handle the complex •

dynamic interactions between the heat pipes, the deck, and the ·ground. Parametric:

studies based on this model were used to formulate a heat pipe system thermal design•

procedure which is presented in the design manual. The heat pipes accounted fo.r 59% ,

of the total bridge cost with the evaporators generating 69% of the system's expense;'

but it wo~ld be economically viable to utilize a few ground source heat pipes to heat

only the tire tracks and gutters.


Format:
PDF
Funding:
DTFH61-80-C-00053
Collection(s):
US Transportation Collection
Main Document Checksum:
[+]
urn:sha256:bfc7e63f0ba2317196c77f43c98b2a4b5c22c1a83c3b722266d71b3a1e95c10c
Download URL:
https://rosap.ntl.bts.gov/view/dot/25905/dot_25905_DS1.pdf
File Type:

Supporting Files

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