Abstract: The present invention is directed to a hybrid thermosyphon which may be rapidly deployed to create a frozen soil barrier for containing toxic spills. In a particular embodiment, a plurality of thermosyphons are deployed for freezing the soil around and under a defined area of soil; each thermosyphon contains a working fluid and includes an evaporator section for contact with the soil for removing heat therefrom by evaporation of the working fluid. A condenser section in flow communication with evaporator section and remote from the soil transfers heat from the working fluid to ambient by heat exchange and subsequent condensation of the working fluid when the ambient is lower than the temperature of the soil. An active refrigeration stage in heat exchange relation with at least a portion of the condenser section removes heat from the working fluid by heat exchange when the ambient is above the soil temperature.

Abstract: A thermosyphon for use in frozen or unfrozen soil includes an evaporator tion embedded in the soil, a condenser section exposed to ambient air, an intermediate section connecting the two sections and a heat exchanger connected to a mechanical refrigeration source and operable to cool either the condenser or the intermediate section of the thermosyphon during periods when the ambient temperature is higher than that at which passive thermosyphonic cooling occurs.

Abstract: A thermosyphon for removing heat from a permafrost foundation, the invent can be installed in a frozen foundation with an evaporator section disposed either horizontally or with a negative (up) slope, thereby allowing the evaporator section of the thermosyphon to be buried in a more shallow location of the foundation than is possible with conventional thermosyphon devices. The thermosyphon of the invention has a condensate collection ring near the lowest point but higher than any point in the evaporator of a condenser section which extends above the permafrost foundation and into heat exchange contact with low-temperature above-ground air. Condensate formed in the condenser section by heat exchange with the air is collected in the collection ring and ducted through a condensate return tube to a desirable location within the evaporator section, usually the extreme distal end thereof.