Insulated structure including cavities holding aerogel connected to a vacuum sustaining unit
A thermal insulation system includes an evacuated structure having an internal space filled with an aerogel layer, in which a vacuum is sustained by a vacuum pump operating when it is determined that a pressure within the internal space has risen to a predetermined level. For example, such a system is used within a dome structure extending over and around a heat receiving structure within a solar heating system or within a system providing thermal insulation for a building structure, a refrigerator, or a railroad car.
This is a continuation-in-part of a copending U.S. patent application Ser. No. 12/592,085, filed Nov. 19, 2009. This application claims the benefit of a prior-filed U.S. Provisional Patent Application No. 61/395,886, filed May 18, 2010 and of U.S. Provisional Patent Application No. 61/463,703, filed Feb. 22, 2011.
FEDERALLY SPONSORED RESEARCH OR DEVELOPMENTNot Applicable
BACKGROUND OF THE INVENTION1. Field of the Invention
This invention relates to thermal insulation systems, more particularly to such systems including evacuated structures, and yet more particularly to the use of such systems to allow heat retention within solar heat collectors, and to the use of such systems to prevent a transfer of heat into or away from an interior space.
2. Summary of the Background Information
A solar heat collector typically includes a heat receiving structure through which a fluid, such as water, is circulated to be heated by solar radiation. The heat receiving structure comprises elements such as piping, tubing, a reservoir tank, and a thermally conductive structure to absorb heat from radiant energy and to transmit the heat to the fluid. Preferably, a translucent cover is placed over the heat receiving structure, allowing the passage of radiant energy, so that the vessel is heated by sunlight, while minimizing the conduction of heat, allowing the heat receiving structure to rise to a relatively high temperature without substantial heat losses to the atmosphere around the solar heat collector. The effectiveness of the thermal insulation in preventing heat loss to the atmosphere has a significant effect on the overall efficiency of the solar heat collector, particularly when the solar heat collector is operated in a cold climate.
One method that has been applied to provide thermal insulation while allowing the transmission of radiant energy is the use of a pair of glass plates that are spaced apart to form an intervening air space. A single plate of glass has an insulation value of R1, with this value being increased to R2 when a second plate is installed to provide a separate air space. Evacuating the air within the space between the glass plates can provide substantially higher insulation values of R30 to R50, at the cost of a need to provide air tight seals around the edges of the glass plates and of a need to provide a structure that can withstand a pressure of about 15 psi acting on each of the plates. However, the use of structures including evacuated spaces for thermal insulation has been the brittleness and relatively low strength of the glass materials generally used and by a lack of reliability of such structures in large thermally insulating systems because small leaks result in a loss of vacuum.
The patent literature includes a number of descriptions of structures for reducing the transfer of heat through the use of spaced-apart glass plates on opposite sides of an evacuated space. For example, U.S. Pat. No. 2,216,332 describes a window including a pair of spaced-apart glass plates and a pipe extending within the wall from the space between the glass plates. The pipe extends to a valve that can be opened to withdraw air form the space between the plates or to return air to this space. A supporting structure, composed of slotted, interlocking vertical and horizontal spacers dividing the space between the plates into a number of smaller rectangular spaces, extends between the plates to help resist the atmospheric pressure acting on the plates when air is removed from this space.
U.S. Pat. No. 3,990,201 describes an evacuated dual pane window structure is provided for reducing heat loss through the window structure. The window structure comprises a pair of closely spaced panes of glass having a spacing of less than 0.25 inch with a spacer means positioned between and uniformly spaced in the area between the panes, and sealing means such as an O-ring positioned around the perimeter and between the panes of glass. A vacuum=pump may be provided for evacuating the area between the panes of glass for reducing thermal losses through the window structure. Reflective coatings may; be provided on the inside surfaces of the glass. A plurality of windows of the above structure may be connected by manifold piping to a single vacuum pump, which is actuated by a thermostat when a preset temperature differential exists between the outside and the inside of the building where the windows are used.
U.S. Pat. No. 4,184,480 describes a conventional flat plate solar heat collector pro-vided with a contoured vacuum insulation window supported solely about its peripheral edge portions. The window is a composite formed from a pair of minimum thickness complementarily contoured glass sheets, which with the exception of their peripheral portions which are sealed together, are spaced apart from one another so as to provide an evacuated chamber therebetween and thus insulate one sheet from the other. The window formed by the nested or complementary contoured glass sheets is contoured in both its longitudinal and lateral directions, such that in its longitudinal direction the window is composed of a plurality of sinusoidal corrugations whereas in its lateral direction the peaks of such corrugations are contoured in the form of paraboloids so as to provide maximum uniform tensile strength to the window such that it may withstand the forces generated thereon by the atmosphere. However, the size of the insulated glass member is limited by the forces, principally caused by the air pressure acting on the two glass sections, and possibly additionally by manufacturing and transportation difficulties associated with handling and forming large pieces of glass. What is needed is a method for a way to provide a thermally insulating cover over a larger and taller solar heat collector.
Other patents describe methods for sealing the interface between glass plates and structural framing members and for providing channels for the evacuation of air between the glass plates to form thermally insulating structures. For example, U.S. Pat. No. 6,383,580 describes a vacuum insulating glass (IG) unit and method-of making the same. An edge-mounted pump-out structure is provided, including a pre-positionable insert capable of receiving a pump-out tube therein. Following formation of the edge-mounted pump-out structure and its positioning on the unit, an edge seal is formed for hermetically sealing off the low pressure space located between the substrates.
U.S. Pat. No. 6,506,272 describes a vacuum insulating glass (IG) unit. In certain embodiments, the internal cavity is evacuated (i.e., pumped out) via a pump-out aperture. A cover with one or more sealing element(s) may be provided over the pump-out aperture so that during the pump-out process air flows out of the internal cavity and through space(s) between adjacent sealing elements or sealing element portions. Following evacuation or pumping out, the sealing element(s) is/are heated and the sealing member may be pressed downwardly toward the substrate. This causes the heat-softened sealing element(s) to expand horizontally and merge with one another so as to form a hermetic seal around the pump-out aperture and between the sealing member and the substrate.
U.S. Pat. No. 5,902,652 describes a method for providing pillars to space apart thermally insulating glass panels that are spaced apart, a method for providing an improved edge seal around the glass panels, and a method for providing an improved pump-out tube for use during construction of the panels.
The patent literature includes a number of descriptions of the use of aerogel layers to provide mechanical support within panel assemblies having spaced-apart panels, with the space between the panels being filled by aerogel. Examples of such panel assemblies range from small windows in opto-electronic devices to large windows in buildings. The patent literature additionally includes a number of descriptions of processes for manufacturing aerogels.
An aerogel was first created by Samuel Stephens Kistler in 1931. Aerogels are produced by extracting the liquid component of a gel through supercritical drying, allowing a liquid content of the gel to be slowly drawn off without causing the solid matrix in the gel to collapse from capillary action. While the first aerogels were produced from silica gels, Kistler later made aerogels based on alumina, chromic, and tin oxide. Carbon aerogels were first developed in the late 1980's.
SUMMARY OF THE INVENTIONVarious difficulties and shortcomings of prior-art thermally insulating systems including evacuated spaces are overcome through the use of the present invention. A dome-shaped central space within a thermally insulating system is provided for holding the heat-receiving portion of a solar heating system. The mechanical weakness of panels extending adjacent evacuated spaces is overcome by providing aerogel layers within the evacuated spaces to keep the panels from being pulled together as the spaces are evacuated. Aerogels are manufactured materials having the lowest bulk density of any known porous solid, being derived from a gel in which a liquid component is replaced by a gas, resulting in an extremely low density porous solid that is particularly affected as a thermal insulator. Because of the porosity of the material, a vacuum can be readily achieved within an aerogel layer. The use of a vacuum instead of air or another gas within the porous layer further enhances the thermal insulation properties of the layer. In applications where transparency is not needed, a strong and resilient material, such as a metal, is used in place of the glass. The reliable, long-term use of large thermally insulating systems is achieved through the use of vacuum sustaining units to make the systems tolerable of small leaks.
In accordance with a first aspect of the invention, a thermally insulating system is provided. The thermally active system includes a thermally insulating structure includes an internal space formed by internal surfaces; an aerogel layer, and a vacuum sustaining unit. The aerogel layer extends between at least parts of the internal surfaces within the internal space. The vacuum sustaining unit including a first input tube connected to the internal space, a pressure sensor sensing a pressure within the internal space; and a vacuum pump evacuating air from the internal space in response to a signal from the pressure sensor indicating that a pressure within the internal space has risen above a predetermined level.
In accordance with a second aspect of the invention, solar heating apparatus is provided, including a heat receiving structure, through which a fluid flows to be heated by solar radiation; and a thermally insulating structure. The thermally insulating structure includes a floor structure and a dome-shaped structure, extending upward from the floor structure. The dome-shaped structure includes an internal surface forming a central space holding the heat-receiving structure and extending from the internal surface to the floor structure. The dome-shaped structure also includes at least one outward-facing surface coated with a selective material having a thermal absorption that is significantly greater than its thermal emissivity.
In first and second embodiments of the invention, the thermally insulating structure includes a floor structure and a dome-shaped structure, extending upward from the floor structure, and the dome-shaped structure includes an internal surface forming a central space extending from the internal surface to the floor structure, and an external surface. The internal space extends within the dome-shaped structure, separate from the central space and between the internal and external surfaces, and the dome-shaped structure transmits solar radiation from outside the dome-shaped structure to the central space within the dome-shaped structure. The floor structure may include a flat inner plate and a flat outer plate, each composed of a strong and resilient material; a frame holding these plates in a spaced-apart relationship, an aerogel layer, and a second input tube. The frame forms an inner space extending within the frame and between the flat inner and outer plates, with the aerogel layer being held within the inner space, extending within the frame and between the flat inner and outer plates; and with the second input tube connecting the inner space within the floor structure with the vacuum sustaining unit. The thermally insulating system may additionally include a conduit connecting the central space with an external space.
In the first embodiment of the invention, the dome-shaped structure includes an inner dome, an outer dome, a gasket, and at least one bracket. The inner dome includes a dome-shaped portion having an inner surface forming the internal surface, an outer surface, and a lower surface, with a lower flange extending outwardly around the lower surface. The outer dome includes a dome-shaped portion having an inner surface, an outer surface forming the external surface, and a lower surface, upwardly disposed from the lower flange of the inner dome, with an upper flange extending outwardly around the lower surface of the outer dome. The gasket extends between the lower flange and the upper flange to enclose a space extending between the inner and outer translucent domes to form the internal space; and the bracket(s) hold the inner and outer translucent domes in a spaced-apart relationship. At least one of the outer surfaces may be coated with a selective material having a thermal absorption that is significantly greater than its thermal emissivity, with both the inner and outer domes being composed of a translucent material, or with at least one of these domes being composed of an opaque material. (As the term is used herein, “translucent” materials are understood to include transparent materials.)
In the second embodiment of the invention, the dome-shaped structure includes a dome-shaped framework including a plurality of frame openings, and an inner sheet and an outer sheet held within each of the frame openings. The inner and outer translucent sheets are held in a spaced-apart relationship to form a portion of the internal space, with an aerogel layer extending within each portion of the internal space. The portions of the internal space in adjacent frame openings are connected by openings within the framework to form the internal space. The dome-shaped framework may additionally include a door section mounted to be moved between an open position and a closed position, and a flexible tube extending between the door and an adjacent surface of the dome-shaped framework. Access from outside the dome-shaped structure to the central space within the dome-shaped structure is then provided with the door section in the open position and prevented with the door section in the closed position. The door section then extends around one of the frame openings, holding the inner and outer sheets within the frame opening in the door section, while the flexible hose connects the portion of the internal space between the inner and outer translucent curved sheets within the frame opening in the door section with the portion of the internal space within an adjacent frame opening. The dome-shaped framework may additionally include an opening through which a lens concentrates solar radiation within the central space. The inner sheet and the outer sheet held within each frame opening may be composed of a translucent material, or at least one of these sheets may be composed of an opaque material, with at least one of the outer surfaces being coated with a selective material having a thermal absorption that is significantly greater than its thermal emissivity.
In the third embodiment of the invention, the thermally insulating structure comprises a plurality of thermally insulating panels, each including a flat inner plate composed of a strong and resilient material, a flat outer plate composed of a strong and resilient material, and a frame holding the flat inner and outer plates in a spaced-apart relationship while forming an inner space extending within the frame and between the flat inner and outer plates. A portion of the aerogel layer extends between the flat inner plate and the flat outer plate within each of the thermally insulating panels. The interior space within each of the thermally insulating panels is connected to the vacuum sustaining unit. The interior space within each of the thermally insulating panels may be connected to the vacuum sustaining unit by a common evacuation tube, or interior spaces within adjacent thermally insulating panels are connected by openings extending through adjacent portions of the frames within the adjacent thermally insulating panels. The thermally insulating panels may form a box structure, extending around a central space, and a door structure, with the box structure including as access opening, and with the door structure being movable between a closed position, extending within the first access opening, and an open position. Access into the central space is provided with the door structure in the open position and prevented with the door structure in the closed position. The door structure includes one of the thermally insulating panels, connected to the vacuum sustaining unit by a path including a flexible hose. Such a box structure may be used within a refrigerator, a container, or a railroad car.
A solar heat collector typically includes a heat receiving structure through which a fluid, such as water, is circulated to be heated by solar radiation. The heat receiving structure comprises elements such as piping, tubing, a reservoir tank, and a thermally conductive structure to absorb heat from radiant energy and to transmit the heat to the fluid. Preferably, a translucent cover is placed over the heat receiving structure, allowing the passage of radiant energy, so that the vessel is heated by sunlight, while minimizing the conduction of heat, allowing the heat receiving structure to rise to a relatively high temperature without substantial heat losses to the atmosphere around the solar heat collector. The effectiveness of the thermal insulation in preventing heat loss to the atmosphere has a significant effect on the overall efficiency of the solar heat collector, particularly when the solar heat collector is operated in a cold climate or if it is desired to operate the solar heat collector at a relatively high temperature needed for the production of mechanical power to drive an electrical generator. For example, U.S. Pat. No. 7,870,855, the disclosure of which is incorporated herein by reference, describes a solar heating system including dome-shaped apparatus that is heated by solar radiation. Other descriptions of solar heating systems including dome-shaped heat receiving structures are found in the disclosures of U.S. Pat. Nos. 4,057,048, 4,136,670, 4,305,383, and 5,427,628, each of which is incorporated herein by reference.
A solar heat collector having a dome-shaped structure built in accordance with a first embodiment of the present invention will first be discussed with reference being made to
Within the frame 102, each of the legs 104 includes a pair of tubes 112, disposed in a circular pattern 113 around a central axis 114 of the hybrid solar heat collector 100 and extending upward, in the direction of arrow 116 and inward, toward the central axis 114. The legs 104 include an inlet/outlet leg 115, in which the tubes 112 are connected to an inlet tube 117 and an intermediate tube 118, and a number of interconnected legs 119. In each of the interconnected legs 119, the tubes 112 are connected at a lower end 120 by connection elements 122. Tubes 112 within adjacent legs 104 are connected at an upper end 124 by connection elements 126, forming a first fluid path 128 extending through the frame 102 from the inlet tube 117 to the intermediate tube 118. In this way, various tubular elements are used both as tubes forming the first fluid path 128 and as struts forming the structure of the frame 102. It is understood that the connections between tubes 112 in individual legs 104 may alternately be made at the upper ends 124, with connections between tubes in adjacent legs 104 being made at the lower ends 120.
In a system heating water for domestic use, the first fluid path 128 within the inlet tube 130 is connected to an inlet water tube 140 through an anti-scald valve 142, and to the reservoir 108 through an intermediate tube 118. The reservoir 108 includes a heater 145, such as an electrical heating element 146 that is connected to an electrical inlet 148 in response to a thermal switch 150. A reservoir outlet tube 152 from the reservoir 108 is connected to an outlet water tube 154 through the anti-scald valve 142. For example, the thermal valve 150 is set to turn the heating element 146 on when the temperature of water within the reservoir 108 is below 90 degrees F., so that hot water can be provided under conditions in which heating by solar radiation alone is insufficient, and additionally so that a space 156 within the translucent dome structure 110 is sufficiently heated by the reservoir 108 to prevent the freezing of water in the first fluid path 128 through the frame 102. The anti-scald valve 142 senses the temperature of water flowing into the outlet water tube 154. When the temperature is below a potentially scalding level, such as, for example, 49 deg C. (120 deg F.), water flows from the inlet water tube 140 to the inlet tube 132 within the frame 104 and from the reservoir outlet tube 152 to the outlet water tube 154. When this temperature is at or above this potentially scalding level, water from the inlet water tube 140 is mixed with water from the reservoir outlet tube 152 within the anti-scald valve 142, with the resulting mixture being delivered through the water outlet tube 154.
The dome structure 110 includes an outer dome 160 and an inner dome 162, between which a space 164 is provided to reduce a loss of heat from a central space 156 within the inner dome 162 to the surrounding atmosphere 166. Preferably, a partial vacuum is maintained within the space 164 by a vacuum sustaining unit 167. Preferably, structural support between the outer dome 160 and the inner dome 162 is provided by an aerogel layer 168 extending within the space 164 between the domes 160, 162. Each of the domes 160, 162 includes an outward extending flange 169, which is held in place on a floor 170 of the hybrid solar heat collector 100 by a number of brackets 172 fastened to the floor 170 with a number of screws 174. A gasket 173 disposed between the flange 169 of the outer dome 160 and the flange 169 of the inner dome 162 seals the space 164 between these domes 160, 162, with the gasket 173 being compressed as the screws 174 are tightened.
A central portion 179 of the transverse hose 106 is wound in a continuous, generally spiral, form around the frame 102 from a lower turn 180 to an upper turn 182, with a number of intermediate turns 184 extending therebetween. In
The transverse hose 106 is composed, for example, of a metal or thermoplastic material having an outwardly extending stiffening structure 198, such as corrugations, bellows, or a helical element extending along the transverse hose 106, which function to allow the transverse hose 180 to retain its circumferential stiffness (i.e. to remain round while avoiding collapsing) when the hose 106 is bent sharply. The transverse hose 106 may be formed as an integral plastic or metal tubular structure by molding or forming, or as a fabricated structure, such as a structure fabricated from a number of metal parts or a plastic tube attached to extend along a metal helical spring. This type of structure allows the transverse hose 106 to be of a diameter sufficiently large to permit the flow of a gas, such as air, through the transverse hose 106, to be heated directly within the solar heat collector 100 without a need for a separate path through which a liquid is pumped and a heat exchanger to heat the air from the liquid.
Preferably, the solar heat collector 100 includes an insulated floor structure 200 formed as a thermally insulating vacuum panel structure including the floor 170, a lower plate 201, and a frame 202, which are attached and sealed to one another so that an internal space 203 is formed, with the internal space 203 being evacuated by the vacuum sustaining unit 167 through an evacuation tube 204 (shown in
It is noted that the shape of the hemispherical portions 175 of each of the translucent domes 116, 118 is considered ideal for resisting internal and external pressure. Evidence of this is seen in the design of tanks for storing gas at relatively high internal pressures, which are generally spherical or cylindrical with hemispherical ends, and in the design of deep diving equipment, including diving helmets and submersible vehicles, which generally include spherically shaped surface for resisting high external pressures. The aerogel layer 168 provides additional resistance to the forces pulling the domes 116, 118 together as a partial vacuum is applied by the vacuum sustaining unit 167. Nevertheless, if additional structure is needed to maintain the space 132 between the translucent domes 116, 118, spacers (not shown) may be attached to extend between the translucent domes 116, 118.
While, in the example of
Thus, through operation of the vacuum sustaining unit 167, the dome shaped structure 110 and the floor structure 126 become evacuated structures, with air being evacuated from the internal space 132 of the dome-shaped structure 110 and the internal space 148 of the floor structure 126. As the term is used herein, the evacuation of air does not mean that a perfect vacuum is achieved or approximated, but rather that a pressure low enough to substantially reduce the transfer of heat is achieved.
Referring again to
A solar heat collector having a dome-shaped structure built in accordance with a second embodiment of the invention will now be discussed, with reference being made to
For example, the translucent sheets 336, 338 are composed of glass or of a translucent thermoplastic material. The formation of an effective vacuum within the spaces 342 through the use of the vacuum sustaining unit 167 results in the application of significant atmospheric pressures trying to push the adjacent translucent sheets 336, 338 together, but these forces are resisted by the aerogel layer 343 in each of the spaces 342. Shattering may be prevented by attaching an impact resistant film to one or more of the surfaces 345 of the translucent sheets 336, 338. Furthermore, significant strengthening may be achieved by composing either or both of the translucent sheets 336, 338 of a translucent ceramic material.
The dome-shaped structure 300 preferably additionally includes a conduit 358 connecting the central space 156 within the inner dome 162 with a space 166 outside the dome structure 300. For example, the conduit 218a may carry electrical wires to a power source or a control system. The conduit 218a prevents the formation of a substantial vacuum within the central space 156 in the event that a leak occurs between one of the internal spaces 342 of the dome-shaped structure 110 and the internal space 148 of the floor structure 126, preventing a possible structural failure of the dome-shaped structure 300.
The mounting and latching of the door 386 will now be discussed with reference being made to
The lens 454 concentrates solar radiant energy on a dish-shaped absorber 456 located, for example at the focal plane of the lens, above a floor structure 458. The dish-shaped absorber 456 absorbs energy that heats the air within the internal space 446, and additionally reflects a portion of the solar radiant energy to heat the frame 448 and transverse elements 450. An electrically-driven fan 452 is preferably additionally provided to circulate air within the internal space 446. Preferably, the dish-shaped absorber 456 is spaced away from the floor structure 458, so that the fan 452 can circulate air both above and under the disk-shaped absorber 456. The dish-shaped absorber 456 may be covered with thermally absorbing and reradiating materials, such as rusty steel plates. The internal space 446 may additionally include a reservoir 460 holding fluid stored at the elevated temperature of the space 446 for later use. The reservoir 460 may be connected to a fluid path within the frame 448, within the transverse elements 450 or elsewhere. Other aspects of the dome-shaped structure 440 and the solar heat collecting dome 442 are as described above in reference to
Thus, though operation of the vacuum sustaining unit 167, a dome shaped structure (as described above in reference to
Curving the translucent sheets 336, 338, as shown in
The use of coatings of selective materials in accordance with versions of the present invention will now be discussed with reference being made to
Referring again to
In accordance with a third embodiment of the invention, a thermally insulating system is provided, including at least one cavity connected to a vacuum sustaining unit and filled with an aerogel. Examples of such insulating systems will now be discussed, with reference being made to
The thermal insulation panel 610 of
While
Versions of the thermal insulation panel 610 may be used within appliances to form internal spaces that can be cooled or heated to a desired temperature with very little transfer of heat to or from the ambient air. For example
Referring first to
Referring to
The vacuum sustaining unit 167 may be operated through the use of a rechargeable battery that is plugged into the electrical system of a truck carrying the container. Furthermore, the container 800 may additionally include a refrigeration system (not shown) sharing a power source with the vacuum sustaining unit 167. Alternatively, the unit 167 may not be provided with the container 800, with an external connection to a manifold tube 832 being instead provided for periodic use of an external version of the vacuum sustaining unit 167.
The insulating panels 610 within each of the door structures 856 are connected with the insulating panels 610 within a box structure 860 by means of a flexible tube 864 resting within a tray 866. Preferably, the tray 864 is installed near the roof of the railroad car 850, with the tubes 862 being attached near the top of the doors 854.
While the invention has been shown in its preferred embodiments and versions with some degree of particularity, it is understood that this description has only been given by way of example, and that many changes can be made without departing from the spirit and scope of the invention, as defined by the appended claims.
Claims
1. A thermally insulating system comprising:
- a thermally insulating structure including an internal space formed by internal surfaces;
- an aerogel layer extending between at least parts of the internal surfaces within the internal space;
- a vacuum sustaining unit including a first input tube connected to the internal space, a pressure sensor sensing a pressure within the internal space; and a vacuum pump evacuating air from the internal space in response to a signal from the pressure sensor indicating that a pressure within the internal space has risen above a predetermined level.
2. The thermally insulating system of claim 1, wherein
- the thermally insulating structure includes a floor structure and a dome-shaped structure, extending upward from the floor structure,
- the dome-shaped structure includes an internal surface forming a central space extending from the internal surface to the floor structure, and an external surface,
- the internal space extends within the dome-shaped structure, separate from the central space and between the internal and external surfaces, and
- the dome-shaped structure transmits solar radiation from outside the dome-shaped structure to the central space within the dome-shaped structure.
3. The thermally insulating system of claim 2, wherein the dome-shaped structure comprises:
- an inner dome including a dome-shaped portion having an inner surface forming the internal surface, an outer surface, and a lower surface, with a lower flange extending outwardly around the lower surface;
- an outer dome including a dome-shaped portion having an inner surface, an outer surface forming the external surface, and a lower surface, upwardly disposed from the lower flange of the inner dome, with an upper flange extending outwardly around the lower surface of the outer dome;
- a gasket extending between the lower flange and the upper flange to enclose a space extending between the inner and outer translucent domes to form the internal space; and
- at least one bracket holding the inner and outer translucent domes in a spaced-apart relationship.
4. The thermally insulating system of claim 3, wherein
- the dome-shaped portions of the inner dome and the outer dome are each composed of a translucent material, and
- at least one of the outer surfaces is coated with a selective material having a thermal absorption and a thermal emissivity, and
- the thermal absorption of the selective material is significantly greater than the thermal emissivity of the selective material.
5. The thermally insulating system of claim 3, wherein
- at least one of the dome shaped portions is composed of an opaque material,
- at least one of the outer surfaces is coated with a selective material having a thermal absorption and a thermal emissivity, and
- the thermal absorption of the selective material is significantly greater than the thermal emissivity of the selective material.
6. The thermally insulating system of claim 2, wherein the dome-shaped structure comprises;
- a dome-shaped framework including a plurality of frame openings;
- an inner sheet and an outer sheet held within each frame opening within the plurality of frame openings, wherein the inner and outer translucent sheets are held in a spaced-apart relationship to form a portion of the internal space, and wherein an aerogel layer extends within the portion of the internal space; and
- a plurality of openings connecting the portions of the internal space in adjacent frame openings to form the internal space.
7. The thermally insulating system of claim 6, wherein
- the dome-shaped framework additionally comprises a door section mounted to be moved between an open position and a closed position, and a flexible tube extending between the door and an adjacent surface of the dome-shaped framework;
- access from outside the dome-shaped structure to the central space within the dome-shaped structure is provided with the door section in the open position and prevented with the door section in the closed position
- the door section extends around one of the frame openings,
- the door section holds the inner and outer sheets within the frame opening in the door section, and
- the flexible hose connects the portion of the internal space between the inner and outer translucent curved sheets within the frame opening in the door section with the portion of the internal space within an adjacent frame opening.
8. The thermally insulating system of claim 6, wherein the dome-shaped framework additionally includes an opening through which a lens concentrates solar radiation within the central space.
9. The thermally insulating system of claim 6, wherein
- the inner sheet and the outer sheet held within each frame opening are composed of a translucent material,
- at least one of the outer surfaces is coated with a selective material having a thermal absorption and a thermal emissivity, and
- the thermal absorption of the selective material is significantly greater than the thermal emissivity of the selective material.
10. The thermally insulating system of claim 6, wherein
- at least one of the inner and outer sheets held within each frame opening is composed of an opaque material,
- the inner and outer sheets held within each frame opening each have an outer surface,
- at least one of the outer surfaces is coated with a selective material having a thermal absorption and a thermal emissivity, and
- the thermal absorption of the selective material is significantly greater than the thermal emissivity of the selective material.
11. The thermally insulating system of claim 2, wherein the floor structure includes:
- a flat inner plate composed of a strong and resilient material;
- a flat outer plate composed of a strong and resilient material;
- a frame holding the flat inner and outer plates in a spaced-apart relationship and forming an inner space extending within the frame and between the flat inner and outer plates;
- an aerogel layer held within the inner space extending within the frame and between the flat inner and outer plates; and
- a second input tube connecting the inner space within the floor structure with the vacuum sustaining unit.
12. The thermally insulating system of claim 2, additionally including a conduit connecting the central space with an external space.
13. The thermally insulating system of claim 1, wherein
- the thermally insulating structure comprises a plurality of thermally insulating panels,
- each of the thermally insulating panels includes a flat inner plate composed of a strong and resilient material, a flat outer plate composed of a strong and resilient material, and a frame holding the flat inner and outer plates in a spaced-apart relationship and forming an inner space extending within the frame and between the flat inner and outer plates,
- a portion of the aerogel layer extends between the flat inner plate and the flat outer plate within each of the thermally insulating panels and
- the interior space within each of the thermally insulating panels is connected to the vacuum sustaining unit.
14. The thermally insulating system of claim 13, wherein the interior space within each of the thermally insulating panels is connected to the vacuum sustaining unit by a common evacuation tube.
15. The thermally insulating system of claim 13, wherein interior spaces within adjacent thermally insulating panels are connected by openings extending through adjacent portions of the frames within the adjacent thermally insulating panels.
16. The thermally insulating system of claim 13, wherein
- the thermally insulating panels form a box structure, extending around a central space, and a door structure,
- the box structure includes a first access opening.
- the door structure is movable between a closed position, extending within the first access opening, and an open position,
- access into the central space is provided with the door structure in the open position and prevented with the door structure in the closed position, and
- the door structure includes one of the thermally insulating panels, connected to the vacuum sustaining unit by a path including a flexible hose.
17. Solar heating apparatus comprising:
- a heat receiving structure through which a fluid flows to be heated by solar radiation; and
- a thermally insulating structure, including a floor structure and a dome-shaped structure, extending upward from the floor structure, wherein the dome-shaped structure includes an internal surface forming a central space holding the heat-receiving structure and extending from the internal surface to the floor structure, and at least one outward-facing surface coated with a selective material having a thermal absorption and a thermal emissivity, wherein the thermal absorption of the selective material is significantly greater than the thermal emissivity of the selective material.
18. The solar heating apparatus of claim 17, additionally comprising:
- an evacuated internal space extending within the dome-shaped structure, separate from the central space and between the internal and external surfaces, wherein the evacuated internal space is at least partly filled with an aerogel layer, and wherein the dome-shaped structure transmits solar radiation from outside the dome-shaped structure to the central space within the dome-shaped structure; and
- a vacuum sustaining unit including a first input tube connected to the internal space, a pressure sensor sensing a pressure within the internal space; and a vacuum pump evacuating air from the internal space in response to a signal from the pressure sensor indicating that a pressure within the internal space has risen above a predetermined level.
19. The solar heating apparatus of claim 18, wherein the floor structure includes:
- a flat inner plate composed of a strong and resilient material;
- a flat outer plate composed of a strong and resilient material;
- a frame holding the flat inner and outer plates in a spaced-apart relationship and forming an evacuated inner space extending within the frame and between the flat inner and outer plates, wherein the evacuated inner space is at least partly filled with an aerogel layer, and wherein the evacuated inner space is connected to the vacuum sustaining unit.
20. The solar heating apparatus of claim 18, additionally including a conduit connecting the central space with an external space.
Type: Application
Filed: May 16, 2011
Publication Date: Sep 15, 2011
Inventor: Michael Flaherty (Stuart, FL)
Application Number: 13/068,607