Abstract
This paper presents a compendium of applications for thermosyphon type passive refrigeration devices for onshore facilities in the arctic. It's very seldom that thaw-stable permafrost or rock is available to found structures on and facilities need to be located on permafrost that is not thaw-stable. There is a long history of thaw subsidence and differential settlement when facilities on thaw unstable permafrost are not thermally stabilized.
Thermosyphons are the most widely used passive refrigeration devices and have been used since 1960 to provide thermal stability to foundations constructed on permafrost. In the arctic oil patch, thermosyphons have been used since the 1970’s with the largest single application being on the vertical support members for the Trans Alaska Pipeline that traverses Alaska. Early thermosyphon devices were installed vertically, and then in 1978, thermosyphons were first used for subgrade cooling beneath a structure with a slab-on-grade over ice-rich permafrost. In the 1980’s, thermosyphons were used to passively refrigerate the ground beneath heated tanks built on-grade negating the need for active refrigeration systems. In the 1990’s, the loop-type evaporator was developed for thermosyphons and the effective run of the evaporator beneath structures tripled. In the 2000’s, thermosyphons began to be used to solve problems around wellheads where hot oil was brought up through permafrost. Today, thermosyphons have a myriad of applications around the arctic oilfield and many of those are presented herein. Thermosyphons are not suited for all refrigeration applications in the arctic and some limitations are detailed.
