Variable thermal insulation assembly

Abstract

A variable thermal insulation assembly includes at least one array comprising a plurality of sheets of film, wherein the plurality of sheets are in a stacked arrangement and each sheet is bonded to an adjacent sheet along a plurality of longitudinally extending regions such that each pair of adjacent sheets form a plurality of longitudinally extending cavities between adjacent regions of the adjacent sheets, a support frame comprising end elements, wherein the support frame frames the plurality of sheets, wherein support frame is coupled to the array to support the array such that the array may transition between an expanded state in which the array is expanded, and a compressed state in which the array is compressed, within the plane of the frame along the direction perpendicular to the longitudinal axis such that the longitudinally extending cavities are expanded or compressed, wherein in the expanded state, the front edge conforms to one of the second end of the support frame or a second front edge of a second array to form a seal that inhibits air flow between the front edge and the one of the second end of the support frame or the second front edge of the second array.

1 . A variable thermal insulation assembly comprising:
 a frame that circumscribes a thermal actuation region having a gas;   one or more thermal cell array units positioned within the thermal actuation region, each thermal cell array unit comprising:
 a first surface sheet and a second surface sheet, wherein the first and second surface sheets are similarly shaped and define a thermal cell array region therebetween; 
   a thermal cell array positioned within each thermal cell array region and coupled to the first and second surface sheets such that the thermal cell array substantially fills the thermal cell array region;
 wherein each thermal cell array comprises a plurality of sheets and at least two of the sheets in each thermal cell array are flexible sheets; 
   wherein adjacent pairs of said flexible sheets are bonded together along at least one pair of bonding regions that extend substantially parallel to each other such that each pair of flexible sheets defines at least one substantially longitudinally symmetrical cavity between each pair of bonding regions, each longitudinally symmetrical cavity being one of a plurality of thermal cells;
 wherein a distance between each pair of bonding regions is sufficiently small such that the total heat loss arising from convective gas flow within the thermal cells is less than total heat loss arising from thermal conduction of the gas present within the thermal actuation region; 
 wherein the distance between each pair of bonding regions is sufficiently large, and the thermal conductivity of the sheets is sufficiently low, such that heat transfer due to thermal conduction within the sheets is less than the heat loss due to thermal conduction of the gas of the thermal actuation region; 
 wherein each of the plurality of thermal cells is bonded to another thermal cell or a sheet in order to form a connected thermal cell array unit; 
   a position controller coupled to at least one of the first and second surface sheets for applying a control force on at least one of the first and second surface sheets to expand the thermal cell array into an expanded state and compress the thermal cell array into a compressed state within the thermal actuation region to vary a volume of the thermal actuation region that is occupied by the thermal cell array units;   wherein the plurality of sheets are sufficiently thin and formed of one or more materials that are sufficiently compliant such that, for each first and second sheet, when the thermal cell arrays are in the expanded state by the applied control force, a gap between each surface sheet and the adjacent frame surface or surface sheet, is made sufficiently small such that the total heat loss that is attributable to gas flow through the gap is less than the total of the heat loss due to thermal conduction through the thermal cells.   
     
     
         2 . The variable thermal insulation assembly of  claim 1 , wherein the position controller is coupled to the one of the first and second sheets such that, when the control force is applied, the at least one of the first and the second surface sheets move in a direction that is normal to the one of the first and second surface sheet such that, during the moving the first and second surface sheets are maintained substantially parallel to each other. 
     
     
         3 . The variable thermal insulation assembly of  claim 1 , wherein the position controller is coupled to the one of the first and second surface sheets such that, when the control force is applied, the one of the first and second surface sheets pivots whereby a first end of the one of the first and second surface sheet is substantially fixed relative to a corresponding first end of the other of the first and second surface sheets, and a second end of the one of the first and second surface sheets, opposite the first end, moves relative to the second end of the other of the first and second surface sheets. 
     
     
         4 . The variable thermal insulation assembly of  claim 1 , wherein at least some of the plurality of sheets comprising the thermal array are coated on at least a first side by a layer of material having a thermal emissivity of less than 0.2. 
     
     
         5 . The variable thermal insulation assembly of  claim 4 , wherein the material is aluminum. 
     
     
         6 . The variable thermal insulation assembly of  claim 1 , wherein each of the plurality of sheets comprising the thermal array has a curved shape, and the plurality longitudinally extending regions follow the curved shaped such that the formed longitudinally extending cavities have the curved shape. 
     
     
         7 . The variable thermal insulation assembly of  claim 1 , wherein the frame comprises edge elements that circumscribe the thermal actuation region, and a front panel and a back panel coupled to the edge elements to form an enclosed panel that encloses the array. 
     
     
         8 . The variable thermal insulation assembly of  claim 7 , wherein the front panel and back panel are light-transmitting window elements that are fabricated from one of glass, mylar, acrylic, polycarbonate, polyethylene, or ethylene tetrafluoroethylene. 
     
     
         9 . The variable thermal insulation assembly of  claim 8  wherein light-transmitting window elements are diffusely light-transmitting elements. 
     
     
         10 . The variable thermal insulation assembly of  claim 1 , wherein the front panel and the back panel are each formed from a thin, light-transmitting material, wherein the front panel and the back panel are bonded together in a periphery region to define a pillow-shaped cavity within the enclosed panel. 
     
     
         11 . The variable thermal insulation assembly of  claim 10 , wherein the thin, light transmitting material is one of polyethylene, polycarbonate, or ethylene tetrafluoroethylene. 
     
     
         12 - 14 . (canceled) 
     
     
         15 . The variable thermal insulation assembly of  claim 7 , wherein an inner surface of at least one edge element has a reflectivity of at least 80%. 
     
     
         16 . (canceled) 
     
     
         17 . The variable thermal insulation assembly of  claim 1 , wherein the frame comprises a first end element at the first end, a second end element at the second end, and a pair of side elements that connect the first and second end elements, wherein at least one of the side elements includes a seal element for inhibiting airflow through an opening of the plurality of longitudinally extending cavities adjacent to the side element when the array is in the expanded state. 
     
     
         18 . The variable thermal insulation assembly of  claim 17 , wherein the seal element is a first inflatable bladder. 
     
     
         19 . (canceled) 
     
     
         20 . (canceled) 
     
     
         21 . The variable thermal insulation assembly of  claim 1 , wherein the position controller is an electrostatic system wherein:
 the plurality of flexible sheets of the thermal cell array are formed of an electronically insulative material that is coated on one side with an electrically conductive material such that, for each pair of flexible sheets, the electrically conductive material coating of each flexible sheet of the pair are separate by at least one layer of the electrically insulative material;   the variable thermal insulation assembly further comprising:   a controller to apply an electric potential difference between each adjacent pairs of sheets such that the electrically conductive coatings of the adjacent pair of sheets attract each other to cause the array to be in the compressed state; and   a plurality of biasing elements located with the plurality of longitudinally extending cavities to bias adjacent pairs of sheets away from each other to cause the array to be in the expanded state in the absence the controller applying an electrical charge.   
     
     
         22 - 53 . (canceled) 
     
     
         54 . The variable thermal insulation assembly of  claim 8 , wherein the light-transmitting window elements have a first portion that is diffusely light transmitting and a second portion that is non-diffusely light transmitting such that the diffusion characteristics of the transmitted light can be controlled. 
     
     
         55 . The variable thermal insulation assembly of  claim 1 , wherein each thermal cell consists of two flexible film elements, each flexible film element having two edge-bond zones that comprise less than 20% of a surface area of the flexible film element, each edge-bond zone extending in a direction parallel to the longitudinal direction of the flexible film element, and a central bond zone comprising less than 20% of the surface area and extending parallel to the longitudinal direction along the center of the flexible film element, wherein
 each thermal cell is formed by bonding two flexible film elements along the edge bond zones, and wherein   thermal cell are oriented into stacks for which each thermal cell is bonded to an adjacent thermal cell along the central bond zone,   and wherein a plurality of said stacks are oriented within the thermal cell region such that the stacks do not make contact with one another even when thermal cell array unit is in the compressed state.   
     
     
         56 . The variable thermal insulation assembly of  claim 55 , wherein additional thin sheets similar in size and shape to the first and second surface sheets, are positioned within said stacks and bonded there along the film element central bond zones, in order to stabilize the stacks against lateral motion within the stack during controlled movement of the first and/or second sheets. 
     
     
         57 . The variable thermal insulation assembly of  claim 1 , wherein the plurality of sheets are sufficiently thin and formed of one or more materials that are sufficiently compliant such that an average size of the gap, when the thermal cell array is in the expanded state, is less than 5 mm. 
     
     
         58 . The variable thermal insulation assembly of  claim 3 , wherein the frame further comprises edge elements that circumscribe the thermal actuation region, and a front panel and a back panel coupled to the edge elements to form an enclosed panel that encloses the array. 
     
     
         59 . The variable thermal insulation assembly of  claim 3 , wherein the position controller is an electrostatic system wherein:
 the plurality of flexible sheets of the thermal cell array are formed of an electronically insulative material that is coated on one side with an electrically conductive material such that, for each pair of flexible sheets, the electrically conductive material coating of each flexible sheet of the pair are separate by at least one layer of the electrically insulative material;   the variable thermal insulation assembly further comprising:   a controller to apply an electric potential difference between each adjacent pairs of sheets such that the electrically conductive coatings of the adjacent pair of sheets attract each other to cause the array to be in the compressed state; and   a plurality of biasing elements located with the plurality of longitudinally extending cavities to bias adjacent pairs of sheets away from each other to cause the array to be in the expanded state in the absence the controller applying an electrical charge.   
     
     
         60 . The variable thermal insulation assembly of  claim 7 , wherein the position controller is an electrostatic system wherein:
 the plurality of flexible sheets of the thermal cell array are formed of an electronically insulative material that is coated on one side with an electrically conductive material such that, for each pair of flexible sheets, the electrically conductive material coating of each flexible sheet of the pair are separate by at least one layer of the electrically insulative material;   the variable thermal insulation assembly further comprising:   a controller to apply an electric potential difference between each adjacent pairs of sheets such that the electrically conductive coatings of the adjacent pair of sheets attract each other to cause the array to be in the compressed state; and   a plurality of biasing elements located with the plurality of longitudinally extending cavities to bias adjacent pairs of sheets away from each other to cause the array to be in the expanded state in the absence the controller applying an electrical charge.   
     
     
         61 . A variable thermal insulation assembly comprising:
 at least one array comprising a plurality of sheets of film, wherein the plurality of sheets are in a stacked arrangement and each sheet is bonded to an adjacent sheet along a plurality of longitudinally extending regions such that each pair of adjacent sheets form a plurality of longitudinally extending cavities between adjacent regions of the adjacent sheets;   a support frame comprising end elements, wherein the support frame frames the plurality of sheets, wherein support frame is coupled to the array to support the array such that the array may transition between:   an expanded state in which the array is expanded by extending a front side of the array within a plane of the supporting frame in a direction from a first end of the support frame to a second end of the support frame, the direction being perpendicular to a longitudinal axis of the longitudinally extending regions, such that the longitudinally extending cavities are expanded to provide thermal insulation over the support frame; and   a compressed state in which the array is compressed within the plane of the frame along the direction perpendicular to the longitudinal axis such that the longitudinally extending cavities are compressed;   wherein in the expanded state, the front edge conforms to one of the second end of the support frame or a second front edge of a second array to form a seal that inhibits air flow between the front edge and the one of the second end of the support frame or the second front edge of the second array.