Structured Insulation Layer Having Differential Convection Cooling Cavities

Abstract

An insulation structure that provides and insulating and cooling effect for permafrost soils includes an insulation material having a top and a bottom. The insulation material defines a plurality of air cavities extending through the insulation material from the top to the bottom. Each air cavity has an upper end at the top of the insulation material and a lower end at the bottom of the insulation material. The air cavities are configured to provide natural convection of air when a temperature above the top surface of the insulation material is less than a temperature below the bottom surface of the insulation material. Sealing material extends across the upper end and the lower end of each air cavity of the plurality of air cavities.

What is claimed is: 
     
         1 . An insulation structure for insulating permafrost, the insulation structure comprising:
 an insulation material having a top and a bottom, wherein the insulation material defines a plurality of air cavities extending through the insulation material from the top to the bottom, wherein each air cavity has an upper end at the top of the insulation material and a lower end at the bottom of the insulation material, wherein the air cavities are configured to provide natural convection of air when a temperature above the top of the insulation material is less than a temperature below the bottom of the insulation material; and   sealing material extending across the upper end and the lower end of each air cavity of the plurality of air cavities.   
     
     
         2 . The insulation structure of  claim 1 , wherein the sealing material comprises a first sheet laminated to the top of the insulation material and a second sheet laminated to the bottom of the insulation material. 
     
     
         3 . The insulation structure of  claim 1 , wherein the structured insulation material is installed within an embankment, wherein the embankment is one of a roadway, a railway, an airport, a pipeline, a building foundation, or a construction pad, wherein the insulation structure is configured to inhibit permafrost foundation soils underlying the embankment from thawing. 
     
     
         4 . The insulation structure of  claim 1 , wherein the plurality of air cavities are arranged in a hexagonal pattern across the insulation material. 
     
     
         5 . The insulation structure of  claim 4 , wherein each air cavity of the plurality of air cavities has a central axis, wherein each air cavity of the plurality of air cavities is positioned a common distance between the central axis of each other adjacent air cavity, and wherein the common distance is from about 5 cm to about 30 cm. 
     
     
         6 . The insulation structure of  claim 1 , wherein each air cavity of the plurality of air cavities is cylindrical. 
     
     
         7 . The insulation structure of  claim 6 , wherein each of the air cavities has a diameter between about 1 cm to about 10 cm and a height between about 5 cm to about 20 cm. 
     
     
         8 . The insulation structure of  claim 1 , wherein the sealing material substantially seals each of the air cavities at the top and bottom by a laminated air-tight layer. 
     
     
         9 . The insulation structure of  claim 1 , wherein the insulation layer has a height between about 5 cm to about 20 cm. 
     
     
         10 . The insulation structure of  claim 1 , wherein the insulation material comprises foam, wherein the foam comprises one of extruded polystyrene, expanded polystyrene, or urethane. 
     
     
         11 . The insulation structure of  claim 1 , wherein the plurality of air cavities have sufficient dimensions to provide for natural convection of air during a period of unstable temperature gradients. 
     
     
         12 . An insulation structure configured to be positioned within an embankment, the insulation layer comprising:
 a sheet of insulation material having a top and a bottom; and   a plurality of sealed air cavities extending through the sheet of insulation material from the top to the bottom,   wherein each air cavity of the plurality of air cavities is configured to provide natural convection of air within the air cavity during a period of unstable temperature gradients.   
     
     
         13 . The insulation structure of  claim 12 , wherein each of the plurality of air cavities has a cylindrical geometry positioned in a hexagonal pattern through the sheet of insulation material. 
     
     
         14 . The insulation structure of  claim 13 , wherein each air cavity of the plurality of air cavities has a central axis, wherein each air cavity of the plurality of air cavities is positioned a common distance between the central axis of each other adjacent air cavity, and wherein the common distance is from about 5 cm to about 30 cm. 
     
     
         15 . The insulation structure of  claim 13 , wherein each of the plurality of air cavities has a diameter from about 1 cm to about 10 cm and a height from about 5 cm to about 20 cm. 
     
     
         16 . The insulation structure of  claim 12 , wherein the embankment is one of a roadway, a railway, an airport, a pipeline, a building foundation, and a construction pad. 
     
     
         17 . The insulation structure of  claim 12 , wherein the sheet of insulation material has a height between the top and the bottom from about 5 cm to about 20 cm. 
     
     
         18 . The insulation structure of  claim 12 , wherein the sheet of insulation material comprises foam, wherein the foam comprises one of extruded polystyrene, expanded polystyrene, or urethane. 
     
     
         19 . The insulation structure of  claim 12 , further comprising a first sheet laminated to the top of the insulation material and a second sheet laminated to the bottom of the insulation material, wherein the first and second sheets are configured to seal the plurality of sealed air cavities. 
     
     
         20 . The insulation structure of  claim 19 , further comprising a reflective coating on an inwardly facing surface of each of the first and second sheets. 
     
     
         21 . An insulation structure configured to be positioned within an embankment, the insulation layer comprising:
 a sheet of insulation material having a height between about 5 cm to about 20 cm;   a plurality of air cavities positioned through the sheet of insulation material,   wherein each of the plurality of air cavities is configured to provide natural convection of air within the air cavity during a period of unstable temperature gradients,   wherein each of the plurality of air cavities has a cylindrical geometry positioned in a hexagonal pattern through the sheet of insulation material,   wherein each of the air cavities are positioned a common distance between cylinder center points,   wherein the common distance is between about 5 cm to about 30 cm, and   wherein each of the plurality of air cavities has a diameter between about 1 cm to about 10 cm and a height between about 5 cm to about 20 cm; and   a seal that seals each of the plurality of air cavities at the top and bottom by a laminated air-tight layer including a reflective surface.