Thermal insulation device

Patent metadata

Field	Value
Publication number	US-9481994-B2
Application number	US-201314407063-A
Country	US
Kind code	B2
Filing date	Jun 11, 2013
Priority date	Jun 12, 2012
Publication date	Nov 1, 2016
Grant date	Nov 1, 2016

Abstract

The invention relates to a thermal insulation device comprising at least one panel ( 100 ) defining a gas-tight chamber ( 104 ) containing at least two flexible films ( 150, 160 ) suitable for being selectively switched between two states: one of thermal conduction wherein said flexible films ( 150, 160 ) are at least partially in mutual contact, and the other of thermal insulation wherein the flexible films ( 150, 160 ) are separated, under the influence of pressure variations in said gas-tight chamber ( 104 ), applied by fluid control means ( 170 ), characterized in that, in the thermal insulation state, the distance separating the flexible films ( 150, 160 ) is shorter than the average free path of the gas molecules in the space ( 158 ) defined between said flexible films ( 150, 160 ). The invention also relates to a method.

First claim

The invention claimed is:

1. A device for thermal insulation, comprising at least one panel ( 100 ) comprising two walls ( 110 , 120 ) separated by a peripheral main spacer ( 102 ) to define a gastight chamber ( 104 ), and at least two supple films ( 150 , 160 ) arranged in said chamber ( 104 ) and adapted to be switched selectively between two states: that of thermal conduction in which said supple films ( 150 , 160 ) are at least partially in mutual contact and the other of thermal insulation in which the supple films ( 150 , 160 ) are separated, under the influence of variations in pressure inside said airtight chamber ( 104 ) applied by fluid control means ( 170 ), characterized in that in the state of thermal insulation the distance separating the supple films ( 150 , 160 ) is less than the free mean path of gas molecules occupying the volume ( 158 ) defined between said supple films ( 150 , 160 ).

2. The device according to claim 1 , characterized in that the supple films ( 150 , 160 ) are kept spaced apart by spacers ( 140 ).

3. The device according to claim 1 , characterized in that the spacers ( 140 ) comprise end sections ( 142 , 144 ) which are supported on the internal surfaces of the walls ( 110 , 120 ) and a median inserted element ( 146 ) placed between the supple films ( 150 , 160 ).

4. The device according to claim 1 , characterized in that the distance between the supple films ( 150 , 160 ) is controlled by electrostatic forces.

5. The device according to claim 1 , characterized in that the main walls ( 110 , 120 ) and the films ( 150 , 160 ) are optically transparent at least in the visible field.

6. The device according to claim 1 , characterized in that the films ( 150 , 160 ) have an emission coefficient less than 0.1 for wavelengths greater than 0.78 μm.

7. The device according to claim 1 , characterized in that each pair of two adjacent films ( 150 , 160 ) together defines airtight compartments ( 158 ).

8. The device according to claim 1 , characterized in that when the films ( 150 , 160 ) are in the separated state, the pressure prevailing in the compartments defined between the films ( 150 , 160 ) is of the order of 0.12 Pa and the distance separating the films is of the order of 0.6 mm.

9. The device according to claim 1 , characterized in that the walls ( 110 , 120 ) are supple.

10. The device according to claim 1 , characterized in that the films ( 150 , 160 ) have an emission coefficient less than 0.04 for wavelengths greater than 0.78 μm.

11. A method for managing thermal insulation by control of the pressure inside a gastight internal chamber ( 104 ) of a panel ( 100 ) comprising two walls ( 110 , 120 ) separated by a peripheral main spacer ( 102 ) defining the above airtight chamber, and at least two supple films ( 150 , 160 ) arranged in said chamber ( 104 ) and adapted to be switched selectively between two states: that of thermal conduction in which said supple films ( 150 , 160 ) are at least partially in mutual contact, and the other of thermal insulation in which the supple films ( 150 , 160 ) are separated, under the influence of variations in pressure inside said airtight chamber ( 104 ) applied by fluid control means ( 170 ), characterized in that it comprises steps consisting of switching the pressure in said airtight chamber ( 104 ) of the panel ( 100 ) between high pressure such that the films ( 150 , 160 ) are in contact over a substantial part of their surface, to place the device in a state of thermal conduction, and low pressure such that the pressure p in compartments ( 158 ) defined between the films ( 150 , 160 ) imposes a distance between the films ( 150 , 160 ) less than

k

√
2

⁢
π
⁢

⁢

d
2

⁢

T
p

,

a relation in which k represents the Boltzmann constant, d represents the diameter of gas molecules and T represents the absolute temperature, to place the device in a state of thermal insulation, the distance separating the supple films ( 150 , 160 ) being less than the free mean path of gas molecules occupying the volume defined between said supple films.

Assignees

• Electricite De France

Inventors

• Duforestel Thierry
• Milleville Pierre-Henri

Classifications

• E04B1/80

  slab-shaped · CPC title

• E04B1/74 Primary

  Heat, sound or noise insulation, absorption, or reflection (forms of, or arrangements in, rooms for influencing or directing sound E04B1/99); Other building methods affording favourable thermal or acoustical conditions, e.g. accumulating of heat within walls (fire protection E04B1/94; elements chiefly adapted for structural purposes E04C1/00 - E04C3/00; chiefly adapted for surface coverings E04F13/00; as underlayers for floor coverings E04F15/18; closures for wall or like openings E06B) · CPC title

• E04B1/806

  with air or gas pockets included in the slab · CPC title

• E04B1/803

  with vacuum spaces included in the slab · CPC title

• E04B1/76 Primary

  specifically with respect to heat only (heat insulation in general F16L59/00) · CPC title