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|Title:||Application of electrical energy to culvert icing problems : a laboratory study|
|Authors:||Alaska. Dept. of Highways.|
United States. Federal Highway Administration.
Gaskin, D. A. (David A.)
Stanley, Leonard E.
|Publisher:||Cold Regions Research and Engineering Laboratory (U.S.)|
Engineer Research and Development Center (U.S.)
|Series/Report no.:||Technical report (Cold Regions Research and Engineering Laboratory (U.S.)) ; 248.|
Abstract: A laboratory study was made to investigate the use of electric heat cables to counteract culvert icing. An automatic system for producing a thaw tunnel of a preselected diameter was developed and tested. -An 80-in.-long, 1-ft-diam. culvert with a 10-ft copper sheath heating cable modeled a typical Alaskan installation. Tests were made to evaluate several continuous power levels, a short-term percentage timer, and the automatic system. Maximum efficiency (cross section produced/unit energy input) occurred when the cable was operated continuously at its maximum permissible power level. The short-term timer system was less efficient than applying the same amount of energy continuously. The automatic system performed well in the laboratory, but may need additional design work to ensure high reliability in field applications. Observations indicate that the major heat transfer mechanism is convection. Marked constrictions in tunnel size were observed at the ice/air interfaces. These observations imply that the cable should be installed near the bottom of the cuIvert and the end risers doubled or tripled. The relative cost comparison among the three modes of heat cable operation indicated that the continuous operation mode is the most reliable, but the most expensive. The pulsed system was less expensive. The automatic system was the least expensive, within the constraints of the comparison. Six recommendations are made for further studies based upon the experience gained from field studies and the results of the laboratory study.
|Appears in Collections:||CRREL Technical Report|
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