- Passive Ground Freezing Technology: Worldwide Leadership, Innovation, and Experience.

For over 40 years, Arctic Foundations, Inc. has provided its customers and teaming partners rapid, well-conceived solutions to geotechnical problems through the application of their proprietary ground freezing technology.

The company analyzes, designs, manufactures, installs, and operates heat transfer and ground freezing systems that enhance the engineering characteristics of soil and rock. Strengthening soils, controlling water, and immobilizing water borne hazardous contaminants are typical benefits to end-users. AFI systems are designed for the long-term and may well outlast the structures they are supporting or protecting.

An exemplary understanding of the interrelationship of diverse engineering disciplines, and many years of development and operational experience allows AFI to offer its clients superior systems with lower life-cycle costs than its competitors.

Arctic Foundations, Inc.

Technologies

As the arctic, sub-arctic, and antarctic regions of the world are developed, one of the major engineering and construction obstacles is the permafrost. Our frozen lands are a design challenge to planners, engineers, and contractors.

Climatic changes and surface damage due to development have caused thawing and degradation of this frozen ground. Repeated thawing and freezing causes heaving, sloughing, and creeping. It can destroy foundations in a matter of seasons.

SOLUTIONS...

Realizing the need to maintain permafrost and the advantages of freezing previously thawed unstable ground, Erv Long developed the Thermopile system in the late 1950's.

Working at that time for the US Army Corps of Engineers, Long patented his passive thermal transfer process. The first commercial units were installed by the Corps in 1960. These installations at the Aurora communication site are still functioning today.

With hundreds of installations and thousands of units designed, manufactured and installed, AFI has been the leader in state-of-the-art passive ground freezing and thawing systems.

As development continues in the unstable arctic and sub-arctic areas, these systems have become more refined and improved. In addition to providing the premier foundations for buildings, tanks, towers, and other structures on permafrost, AFI has designed and worked with many aspects of the permafrost stabilization problem. They have developed frost-proof bench marks for use by surveyors, pioneered controlled thawing techniques to eliminate frost and frost heave in some areas, and worked extensively on stabilization of land-slide areas. Their experience also includes deployment of impervious frozen barriers to confine hazardous waste and control groundwater, passive freezers, geothermal heating, and water supply dams.

Technologies

- About Arctic Foundations Inc

 
Erv Long
Erv Long

 


Ed Yarmak
Ed Yarmak 

 

 


 

 

 

  

 

LOCATION AND HISTORY:

AFI is incorporated in Alaska and is headquartered in Anchorage. The firm has all operations established at a single location - including management, administration, research, product development, engineering, and manufacturing. AFI has been developing, designing, fabricating, installing, and improving ground freezing systems since its inception in the early 1970's. AFI's technology is based on numerous patents held by Mr. Erwin "Erv" Long, the original being the Long Thermopile that was initially developed by Mr. Long in 1956. Long has also been recognized for his innovative solutions by receiving the Alaska Engineer of the Year award in 1978, and the ASCE's Harold R. Peyton award for Cold Regions Engineering in 1991. 

AFI's Chief Engineer is Edward Yarmak, Jr., a professional engineer with over 29 years of geotechnical experience and over 26 years with the company. Both Long and Yarmak have been published in numerous professional publications and journals spanning their years of experience. They are also members of, and actively involved in, professional societies: ASCE, ASME, SME, ASTM, NSPE, and others.

OVERVIEW OF COMPANY CAPABILITIES:  

AFI's capabilities broadly cover all aspects of thermosyphon product development as it relates to delivering state-of-the-art components to customers, facility owners, and end-users. These capabilities include the fabrication of Thermopiles, Thermoprobes, and related functional components.

Fabrication of thermosyphon products requires high quality welding, surface coating, and all of the preparatory steps associated with these activities. In the case of products that are greater than six inches in diameter, all construction must conform to the ASME pressure vessel code. This mandates that all stages of the operation conforms to the code rules and that the products are subjected to regular inspection at various stages of fabrication. Since AFI has one of the few ASME code authorized fabrication shops in Alaska, all thermosyphon products, regardless of diameter, are welded in conformance with the pressure vessel code. 

Corrosion protection is also a critical step in the production of thermosyphon products. The steel surfaces of these devices are partly exposed to unfrozen soil and atmospheric moisture for scores of years and must be highly resistant to oxidation and corrosive action. These surfaces are cleaned and coated with one or both of AFI's coating processes; aluminum metallizing and fusion-bond epoxy, with the specific applications governing the coating requirement. Both processes are performed in-house.

Continuous improvement of the technology, products, components, and systems is also accomplished in-house. The AFI management, engineering, and production staff seek these opportunities and actively utilize technological developments in peripheral and related industries that complement AFI's technology. Refrigeration equipment, data gathering instrumentation, and computer utilization are just a few examples of peripheral industries that have significant positive impact on AFI's ability to advance its technology and are therefore actively monitored and utilized. 

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Technologies

Two-Phase Thermosyphons

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Two-phase thermosyphons are passive refrigeration devices that transfer heat against gravity. Construction is typically a closed ended tubular vessel charged with a two-phase working fluid. The vapor phase of the working fluid fills the majority of the interior of the vessel, with the liquid phase filling the minority of the volume.

Thermosyphons function because of the two-phase working fluid. The working fluid is contained in a closed, sealed vessel (Thermopile or Thermoprobe) that is partially buried. Thermosyphons have typically functioned passively in cold climates during the winter months, at which time the above-ground portion is subjected to cold ambient air which cools and condenses the working fluid. The condensed fluid gravitates to below-ground level. Below ground, subjected to warmer temperatures, the working fluid warms, vaporizes, and rises upward to repeat the cycle. This continuous recycling is irreversible because the cycling ceases in the summer when the air temperature is above the soil temperature. This closed two-phase process should not be confused with the open two-phase process whereby liquid nitrogen is used in ground freezing applications. The latter process simply releases the nitrogen gas to the atmosphere having gained sufficient heat from the soil to vaporize the liquid nitrogen.

A closed two-phase system can also be used in an active mode and is applicable when the ambient air temperature is above freezing. Such systems are termed "hybrid thermosyphons" and are often needed in temperate applications where reliance on low ambient air temperatures is not feasible. A typical system consists of multiple Thermoprobes, an active (powered) condensing unit, a two-phase working fluid, an interconnecting supply and return piping network, and a control system. Thermoprobes consist of an evaporator and a passive condenser section. Coupled with an active condenser, a Thermoprobe functions actively and removes heat from the ground without direct dependency on the ambient air temperature. The hybrid system can function simultaneously in both passive and active modes, when the ambient temperatures are sufficiently low, thereby reducing energy costs. 

Current state of development and certification:

This technology has been in use since 1960 and as such has been utilized on over 900 installations. Most of these applications have been in arctic climates where soil freezing is accomplished passively (i.e. without the use of power). Active-passive "hybrid" systems have been used in climates where low winter temperatures do not prevail. Such systems are normal for temperate climates. The essence of thermosyphon technology is well developed irrespective of the climate it is applied in.

Availability of technology:

AFI has been continuously developing, fabricating, installing, operating, and advancing thermosyphon technology since the corporation's inception in the early 1970's. As such, the company has the capability and capacity to apply the technology to most any situation in a very expeditious and professional manner. The technology is well developed and is therefore available for application in real situations - it is not an embryonic technology that needs years of developmental engineering to prove.

Improvements of the technology are of course developed with every new project and as techniques improve in-house and in related sectors of the geotechnical industry. Drilling and installation techniques are examples of related technologies that are rapidly advancing, thereby improving the practicality of placing thermoprobes in complex underground configurations.

Technologies

Thermopiles


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Thermopile supporting an antenna tower at the HAARP facility at Gakona, Alaska

Thermopiles are load bearing two-phase thermosyphons that are generally used to found structures where permafrost soils exist. Typical thermopile applications follow:

  • Installation at sites with a frost-susceptible active layer where heave and pile jacking are problems. Thermo-cycling reduces frost heave forces to negligible quantities.
  • Installation in marginal permafrost where pile creep rates are high. Thermo-cycling reduces soil temperatures and subsequently reduces creep rate.
  • Installation at sites with saline permafrost where allowable stresses are reduced due to substantial quantiies of unfrozen water in the soil matrix. Thermo-cycling freezes water near piles and pushes salts away. Also proven effective for moving glycol from a piling face.
  • Installation at sites where development has increased the heat load to the subgrade. Heat transfer rates of the Thermopiles need to be sized to balance or exceed heat load.

 

 

 

 

 

 

Technologies

Thermo Helix-Piles

Thermo Helix-Piles are Thermopiles with helical shear rings attached and can be used in all applications where Thermopiles are appropriate. At one time, individual rings were used instead of the helix. Most applications use a helix that has a strip width of 2 inches (50mm). Typical Thermo Helix-Pile applications follow:

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Thermo Helix-Piles loaded for shipment to Kotzebue, Alaska 

  • Generally, Thermo Helix-Piles support greater loads than adfreeze piles. Shear loading in lieu of adfreeze allows higher unit stresses that equate to shorter embedment depths.
  • Thermo Helix-Piles are used when high transient loads are expected. The flexibility of the helix allows a more uniform load distribution along the pile.
  • Thermo Helix-Piles are used to support  structures where consequences of foundation movement are high. Thermo Helix-Piles offer high redundancy.
  • Useable permafrost stress at helix diameter will be a minimum of twice the useable adfreeze stress at the pile diameter and is limited by the surrounding soil strength.

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Thermo Helix-Piles supporting K-12 School at Kipnuk, Alaska

Technologies

Sample Projects

  • 2007-28-3-Kyrgystan - Kumtor Mine Portal

    Kyrgystan -
    Kumtor Mine Portal

  • 2005-17-1 Chandalar, AK - Heavy Equip Shop

    Chandalar, AK -
    Heavy Equipment Shop

  • 2007-28-1 Kyrgystan - Kumtor Mine Portal

    Kyrgystan -
    Kumtor Mine Portal

  • 2005-51-1 Unalakleet, AK - Bulk Fuel Upgrade

    Unalakleet, AK -
    Bulk Fuel Upgrade

  • 2004-32-2 Prudhoe Bay, AK - Relocatable Heatpipes

    Prudhoe Bay, AK -
    Relocatable Heatpipes

  • 2003-13 Fairbanks, AK - UAF Geist Rd Entrance

    Fairbanks, AK -
    UAF Geist Rd Entrance

  • 2004-32-1 Prudhoe Bay, AK

    Prudhoe Bay, AK -
    Overlength Thermoprobes