WO2012138978A2 - Dome shaped capsules of thermal energy storage material for improved heat storage - Google Patents

Abstract

The invention is directed at articles and devices for thermal energy, storage, and for process of storing energy using these articles and devices. The articles comprise a capsular article 10 having one or more sealed spaces 14, wherein the; sealed spaces encapsulate one or more thermal energy storage materials 26 wherein the capsular article has a first outer radial surface that is generally, concave: and an opposing outer radial surface that is generally convex. Preferred capsular articles are generally dome-shaped. Preferably, the capsular article has one or more fluid passages 16 which are sufficiently large to allow a heat transfer fluid to flow through the one or more fluid passages; and when a heat transfer fluid contacts the capsular article 10 the thermal energy storage material.26 is isolated from- the heat transfer fluid. The invention is also directed at devices including two or more articles arranged so that a fluid, such as a heat transfer fluid, may flow through the fluid passage 16 of an article before, or after flowing through a space between two of the articles. Preferred heat storage devices include a conductive component within the capsule suitable for increasing the heat flow, structural elements between two articles suitable for spacing the articles, or both.

Description

Filed Via EFS @ USPTO.gov on 04-06-2012

Attorney Docket No. 70928 (1062r,177WO)

DOME SHAPED CAPSULES OF THERMAL ENERGY STORAGE MATERIAL

FOR IMPROVED HEAT STORAGE

CLAIM OF BENEFIT OF FILING DATE

[01] The present application claims the benefit of the filing date of U.S. Provisional Application Serial No. 61/472,460, filed on April 6, 2011 , which is hereby incorporated by reference for all purposes.

FIELD OF THE INVENTION

[02] The present invention relates to thermal energy storage using a thermal energy storage material (i.e., TESM) and to the packaging of the TESM to allow for both efficient heat storage and efficient heat transfer. In particular the invention relates, to novel encapsulation designs for improved heat storage devices (i.e. HSDs).

BACKGROUND OF THE INVENTION

[03] Industry in general has been actively seeking a new approaches to capture and store waste heat efficiently such that it can be utilized at a more opportune time. Further, the desire to achieve energy storage in a compact space demands the development of materials that are •capable of storing high energy content per unit weight and unit volume. Areas of potential application of such technology include transportation, solar energy, industrial manufacturing processes as well as municipal and/or commercial building heating.

[04] Regarding the transportation industry; it is well known that internal combustion engines operate inefficiently: Sources of this inefficiency include heat lost via exhaust- cooling,, radiant heat and mechanical losses from the system. It is estimated that more than 30% of the fuel energy supplied to an internal combustion engine (internal combustion engine) is lost to the environment via engine. exhaust.

[05] It is well known that during a "cold start" internal combustion engines operate at substantially lower efficiency, generate more emissions; or both, because combustion is. occurring at a non-optimum temperature and the internal combustion engine needs to perform extra work against friction due to high viscosity of cqld lubricant. This problem is even more important for hybrid electric vehicles in which the internal combustion engine operates intermittently thereby prolonging the cold start conditions, and/or causing a plurality of occurrences of cold start conditions during a single period of operating the vehicle. To help solve this problem,; original equipment manufacturers are looking for a solution capable of efficient storage and release of waste heat. The basic idea is. to recover and, store waste heat .during normal vehicle operation followed by controlled release of this heat at a later time thereby reducing or minimizing the duration and frequency of the cold start condition and ultimately improving internal combustion engine efficiency, reducing emissions, . or both.

[06] To be a practical solution, the energy density arid the thermal power density requirements Filed Via EFS @ USPTO.gov on 04-06-2012

Attorney Docket No. 70928 (1062-177WO)

for a thermal energy storage system are extremely high. Applicants have previously filed U.S. Patent Application No. 12/389,4.16 entitled "Thermal .Energy Storage Materials" and filed on February 20, 2009 (published as US 2009/021 1726 A1 ) which describes features of thermal energy materials; U.S. Patent Application No. 12/389,598 entitled "Heat Storage Devices" and filed on February 20, 2009 (published as. US 2009/0240189A1 ) which describes features, of encapsulated articles, devices, and systems for storing heat; PCT Application No. PCT/US09/67823 entitled "Heat Transfer Systems Utilizing Thermal Energy. Storage Materials" and filed on December 14, 2009 (published as W020 1 /037596 At) which describes features.of heat storage devices for improving heat transfer; arid US Patent Application No. 13/207,607 entitled "Articles arid Devices for Thermal Energy Storage and Methods Thereof and filed on August 1 1 , 2011 (published _:as US 2012/0037148A1 ) which describes features of durable structures for containing TESM in a heat storage device: These previous applications are incorporated herein by reference in their entirety. It will be appreciated that features disclosed in these previous applications may be employed in the present invention.

[07] There are known heat storage devices (\:e.„ HSD) arid exhaust heat recovery devices in the. prior art. However* in order to: provide a long term (e_;g., greater than .about;6 hour) heat storage capability, they generally occupy a large volume, require pumping of a large volume of heat transfer fluid, require a relatively large pump to overcome the hydraulic resistance, and the like. In PCT Application No. PCT/US11/22662 filed January 27 201 1 , also incorporated herein by reference, Applicant disclosed a generally flat design of capsules containing a phase change material which has irnproved the overall efficiency of the HSD and/or thermal energy storage :system. Such a design offered an unprecedented combination of high energy density, high power density, long heat retention time, light weight, , low. hydraulic resistance for heat transfer fluid flow, or any combination thereof.

[08] There is still a need for capsules, such as stackable capsules containing a thermal energy storage, material (i.e., TESM), that can be used for HSDs having high thermal energy storage density; for HSDs having high power density; a capsule having low thermal stresses within the capsules; a H$D having a high fill ratio (he., ratio of the volume of the inner can to. the volume. of the outer can volume).

SUMMARY OF THE INVENTION

[09] One aspect of the invention is a capsular article comprising one or more sealed spaces, wherein the sealed spaces includes a thermal energy storage material (i.e., TESM). encapsulated between two opposing radial walls, each having an outer radial surface. Preferably, one outer radial surface is generally convex and the other outer radial surface is. generally concave. The articles preferably are sufficiently stackable so that they may be stacked and placed in an inner housing (e.g., an insulated housing) having one end that is generally concave and an opposing end that is generally corivex. By having outer radial, surfaces that. Filed Via EFS @ USPtO.gov on 04-06 2012

Attorney Docket No. 70928 (1062-177WO)

generally match the curvature of the housing ends; a stack of the articles may advantageously fill a large portion . of the interior space of the inner housing; Each article preferably has an opening to allow a fluid to flow through the article without contacting the TESM that is sealed in the article. The opening may allow a fluid to flow in the direction of the thickness of the article between the concave outer radial surface and the convex outer radial surface. The articles have an outer periphery which is/the region of the article furthest from the opening. The radial surface and the radial walls are the surfaces and walls that extend partially or entirely from between the opening and the outer periphery. The articles may be used in a device that includes an outer housing, (e.g., an outer can) and an Inner housing (e.g., an inner can) positioned inside the, otiter housing and a space between the housings including a vacuum. The novel design of the articles may yield one or any combination of the following benefits compared to previous designs: 1 ) higher device-level energy density; 2) higher device-level power density;: 3) lower thermal stresses within the capsules; and 4) higher device-level fill ratio as defined by the ratio of the volume of the inner housing to the volume of the outer housing (inner housing or can volume divided by the outer can volume. The articles preferably are capable of being, stacked with the openings of the articles aligned to form a; continuous passage in the axial (i.e., stacking) direction.

[10] Another aspect of the invention is a device including a container (e.g., an inner housing); and a plurality of the. articles having a fluid passage and containing the TESM, such as a plurality of articles described herein, wherein the plurality of articles are stacked so that the fluid passages are aligned axially. The container preferably has one end that is generally concave and an opposing end that, is generally convex.

[11] A process related aspect , of the invention is a method for removing heat from a heat storage device comprising the steps of: flowing a heat transfer fluid having an initial temperature into a heat storage device; flowing the heat transfer fluid through a first axial flow path; dividing the flow of the. heat transfer fluid between a plurality of radial flow paths that each includes a radial component and an axial component; flowing the heat transfer fluid through the radial flow paths, wherein a radial flow path is defined by the space betweeh a. generally convex outer radial surface of an article that contains a thermal energy storage material and a generally, concave outer radial surface of an adjacent article, wherein the thermal energy storage material has a temperature greater than the initial temperature of the heat transfer fluid, so that the heat transfer fluid can remove heat_, from the thermal energy storage material; flowing the heat transfer fluid through a different axial flow path where the plurality of radial flows recorhbine;. and flowing the heat transfer fluid having an exit temperature out of the device; .wherein the exit temperature is greater, than the initial temperature of the heat transfer fluid.

[12] Another process related aspect of the invention is a method for preparing or assembling an article comprising a step of sealingly attaching two sheets each having a surface with a Filed Via EFS @ USPTO^gov on 04-06-2012

Attorney Docket No. 70928 (1062-177WO)

curvature and having corresponding openings, so that an outer surface of the one sheet is generally convex and an opposing outer surface of the other sheet is generally concave.

[13] Another aspect of the invention is directed at a. static mixing element formed from a sheet for mixing the flow of a HTF. The static mixing element preferably includes a plurality of openings, a plurality of features for redirecting and/or dividing the flow of the HTF, including features on opposite sides of the opening that project in different directions.

[14] The articles, , devices, systems and processes of the present invention advantageously are capable of containing a high concentration of TESM so that a large amount of thermal energy can be stored (e.g., having a high energy density), are capable of having a. high surface area between the HTF and the article containing the TESM so that heat can be quickly, transferred into and/or out of the TESM (e.g., having a high power density, preferably greater than about 8 kW/L), are capable of having multiple flow paths that have; similar or equal hydraulic resistance so that heat is uniformly transferred to and/or transferred from different regions,; have a rotational symmetry so that they may be arranged easily;; have a structure that, is strong and durable; have a high heat storage density so that they can be used in applications requiring compact designs, light weight components, or both; have lower hydraulic resistance for a HTF flow (for example, a pressure drop of less than about 1.5 kPa at a. HTF pumping rate of about 10 liters/min) so that the pumping requirements for the HTF are reduced, or an combination thereof.

BRIEF DESCRIPTION OF THE FIGURES

[15] The present invention is further described in the detailed description which follows, in reference to the noted plurality of drawings by way of nqnrlimiting examples of embodiments of the present invention, in which like reference numerals represent similar parts throughout the several views of the drawings, and wherein:

[16] FIGs. ΊΑ,.Β, G and D are drawings of an illustrative capsular article showing features which may be used in a capsular article. FIG. 1A is a top perspective. view showing a sheet having a generally convex radial outer surface, FIG. 1 B is a bottom view perspective of showing a sheet haying a generally concave radial outer surface. FIG.1 C is a cross-sectional perspective from the same orientation as FIG. 1 A, showing the encapsulated TESM and showing an opening that^' creates a path from one radial outer surface to the other radial outer surface. FIG. 1 D. is a diametral cross-section view, illustrating that the article may be characterized by a height, h, a long dimension, L, and a spacing between the radial outer surfaces, x.

[17] FIG. 2A is a perspective view of an illustrative, capsular article having a plurality of segments 50 each containing a sealed space.

[18] FIG. 2B is a perspective view of an illustrative segment 50.of a capsular article.

[19] FIG. 2C is a perspective view of an illustrative capsular article having a plurality of individually sealed spaces. Filed Via.EFS @ USPTO.gov on 04-06-2012

Attorney Docket No. 70928 (1062-177WO)

[20] FIG. 3A and 3B are portions of cross-sections of an illustrative article, showing regions of FIG. 1 D. FIG. 3A shows a region near the opening having a relatively high thickness compared to a region away from the opening, such as the region shown in FIG, 3B.

[21] FIG. 4A is a perspective cross-sectional view of an illustrative article having a generally opposing outer radial surfaces, wherein in radial surface is_. generally concave and the other is generally convex: As illustrated in FIG. 4A, one or. both of the radial surfaces may have a secondary texture or feature, such as radial or spiral grooves that partially or entirely extend between the opening and the outer periphery of the article.

[22] FIG. 4B is a top view of an illustrative article having a non-circular axja| projection. Such an article may be useful in filling an inner housing having a cavity that is non-circular.

[23] FIG. 5 is a diametrical cross-sectional view of a stack bf articles having a generally common axial direction so that their corresponding openings are generally aligned.

[24] FIG- 6 is an illustrative cross-sectional view showing features of a stack of articles in a plane including the axis of the opening, providing a flow path that includes an axial flow through the openings of the articles, a plurality of radial flows between adjacent Articles,; and an axial flow along the outer periphery of the articles.

[25] FIG. 7 is a cross-sectional view of an illustrative stack of articles, in an inner housing having a convex end and a concave end, where, at room temperature, the curvature of one end of the inner housing may be different from the_. curvature of a radial outer surface of the article.

[26] FIG. 8 , is a cross-sectional view of an illustrative HSD including a tube capable of providing a flow of.a HTF into the device,.

[27] FIG.. 9 is a cross-sectional view of an illustrative capsular article including a heat conducting element.

[28] FIG. 10 is a cross-sectional view of a pair of adjacent articles including a static mixing element in the space between the two articles.

[29] FIGs. 11A and 11B illustrate an exemplary static mixing element. FIG. 11A is a top view of the showing a plurality of openings with upward, projections on one side of the opening and downward projections on the other side, of the opening. FIG.. 11 B. is cross-sectional view of the static mixing element with the direction of flow in the left-right direction.

[30] FIGs. 12A, B, C, D are drawings showing features of illustrative heat conducting elements that ma be employed inside an article for increasing a HSD's heat transfer power.

[31] FIG. 13 is a perspective view illustrating an arrangement^'of segments that combined forms a stack capable of fitting into an inner housing having one end that is generally concave and an opposing ed that is generally convex.

[32] FIG. 14 is a schematic of an illustrative heat storage system including a HSD.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

[33] In the following detailed description, the specific embodiments of the present invention are Filed Via EFS @ USPTO.gov on 04-06-2012

Attorney Docket No. 70928 (1062-177WO)

described in connection with its preferred embodiments. However, to the extent that the following description is specific to a particular embodiment or a particular use of the present techniques, it is intended to be illustrative only and merely provides a concise description of the exemplary embodiments. Accordingly, the invention is not limited to the specific embodiments described below, but rather; the invention includes all alternatives, modifications, and equivalents falling within the true scope of the appended claims.

[34] As will be seen from the teachings herein, the present, invention provides unique articles, devices, systems, and process for storing thermal energy and/or transferring stored thermal energy to a fluid. For example/the articles and devices for storing thermal energy of the present invention are more efficient at storing thermal energy, allow for transferring thermal energy more uniformly, allow for increased rates of transferring thermal energy (e:g., higher power capabilities),' allow for transferring thermal energy with a smaller pressure drop of the- HTF, or any combination thereof.

[35] One or more of the aforementioned improvements in the HSD may be accomplished b providing an overall curvature to the generally flat capsular articles .{e.g.. capsules containing a TESM, such as a phase change material) as disclosed in PCT Application No.. PCT/US201 1/022662; The capsular articles preferably have sufficient curvature so that the capsular articles, are dome-shaped. The capsular articles are generally stackable: and preferably have a central opening. Preferably the articles ma be stacked so that the central openings allow for the axial flow of a HTF through the stack of the capsular articles (See FIG. 6). The axial projections of the article may have any shape that fits into the storage space.. The axial projection of the article may be oddly shape or may have a symmetrical shape. The capsular articles in the axial projection may be generally oval, elliptical, rounded rectangle or any other suitable shape that fills well the inner housing (e.g., inner can) of a HSD (i.e., a thermal energy storage device). As such, capsular articles having an axial projection that is generally circular may be.particularly suited for use in a device having a generally cylindrical inner housing.

[36] Various aspects of the invention are predicated on an article including a capsular structure having one or more sealed. spaces ( e._; capsules) and one or more TESMs that are within the encapsulated volume of the one or more sealed spaces, so that the TESM cannot flow but of the article or otherwise be removed from the article. The capsular article has a novel geometry, that includes one or more fluid passages that are sufficiently large so that the capsular article is capable of allowing a fluid (e.g., a HTF) to flow through the fluid passage. The TESMs are sufficiently encapsulated in one or more of the sealed spaces so that when the HTF contacts the capsular article, the TESM is isolated from the fluid. Other aspects of the invention include novel arrangements including a plurality of the articles, novel devices including one or more of the articles, novel processes for manufacturing the article, and novel processes for using one or more of the articles. By employing the novel article, it is possible to assemble devices capable Filed Via EFS @ USPTO.gov on 04-06-2012

Attorney Docket No. 70928 (1062-177WO)

of storing a large quantity of thermal energy, capable of rapidly transferring thermal energy into and/or out of the TESM, capable of being compact, capable of being light weight, capable of having a low pressure drop of a HTF, or ariy combination thereof.

[37] A HSD according to the teachings herein may have a relatively high device-level energy density. The high device-level energy density may be realized due to the TESM, the: capsular articles, or both, occupying more^' of the insulated volume of the HSD; In other words, a portion of the insulated volume of HSD otherwise occupied by a low specific heat capacity material, such as a HTF) in a previously disclosed HSD is now occupied with^" additional TESM. The TESM has a higher heat storage density compared to the. HTF, due to the TESM's relatively high specific heat capacity, relatively high specific heat of fusion, or both.

[38] A HSD. employing capsular articles having an outer radial surface that is generally concave and an opposing outer radial surface that is generally convex may provide a higher power density compared to a heat storage including a generally flat capsular article because of the increase in the total surface area of the: article, because of the decrease in the thickness of the capsular article particularly near the_. outer periphery of the article, or both. A concave or convex outer radial surface of a capsular article will have an active heat transfer contact area with a HTF that is greater compared with a generally flat outer surface: of a capsular article having the same, axial projection, such as disclosed in P.GT Application ip. PCT/US11/022662. The increased surface area also results- in a longer flow path for the HTF as it flows' in the gap between two adjacent capsular articles. Flow between two flat surfaces of adjacent flat articles and flow between two curved radial surfaces of curved article, having the same axial projection, will have generally the same radial flow length. However, only the flow between the two curved radial surfaces will also have an axial flow length. The article having a concave outer radial surface and a convex outer radial surface may have a thickness that tapers from the center of the capsular article to the outer periphery. During a process of transferring heat from a TESM in the capsular article.to a HTF flowing along the outer radial surfaces of . the article, the HTF may •enter the gap between two articles by first flowing through an opening of one article. When the HTF first contacts the article, there will be a driving force for heat transfer, (the difference in temperature between the relatively warm TESM and the relatively cold HTF). As the temperature of the HTF rises while it flows between the two articles, this driving force for heat flow will decrease. To compensate for the decrease in driving force for heat flow, it is advantageous to have the thickness of the article decrease between the opening region and the periphery region. Such a design may result in an article behaving in a more isothermal manner, that is where the temperature of the TESM, averaged over the thickness of the article,, is more uniform and/or the fraction of the TESM in a solid state, averaged over the thickness of the article, is more uniform going from the opening region to the outer periphery. Preferably the article behaves in a generally isothermal manner, where the average temperature of the TESM, Filed Via EFS @ USPTO.gov on 04-06-2012

Attorney Docket No. 70928 (1062-177WO).

- averaged over the thickness, does not vary in the radial direction during a process of transferring heat to the HTF. The increase in the thermokinetic performance of a HSD using capsular articles according to the teachings herein may be achieved without increasing the number of capsules per device and thus their total cost,, in contrast to a straightforward approach of boosting the power density by decreasing the thickness of the capsules and thus increasing their number and.total cost in a device with a fixed total volume of capsular articles.

[39] The capsular articles according to. the teachings herein may have reduced thermal hoop, stress due to a temperature difference between the center and the outer periphery of the article.

Such a reduction in the thermal hoop stress may be attributed to an added degree of deformational freedom. For example, a dome-shaped capsular article may have a high hoop' compliance which results from the ease in which the article can increase or decrease the curvature (e.g., of their dome) in order to accommodate the difference in temperature between the center (e.g., opening region) and the outer periphery. In contrast, a generally flat capsular article, such as disclosed in RCT Application No. PGT/US 1.1/022662, may develop relatively high hoop stresses when the center and the outer periphery have different temperatures,

[40] The capsular articles according to the teachings herein may also_, result in HSDs having a

•higher device-level fill ratio: The fill ratio may be defined by the ratio of the volume of the inner housing to. the volume of the outer housing, where, the outer housing, may be an, outer can. The; spacing between the inner housing arid the outer housing may be used for a vacuum gap to provide thermal insulation. In practice, the above gap may need to be sufficiently large, in order to accommodate one or more- suspension for supporting the inner housing, one or more. compression springs, one or rnore HTF tubes, or any combination thereof. Furthermore, if the inner housing is surrounded by. vacuum, there will be a positive gage pressure and it may be advantageous for the inner housing to have non-zero mean curvature everywhere, so that the need for a high wall thickness arid corresponding high weight of the inner housing may be avoided. A traditional design for such an inner housing is a cylindrical can having hemispherical or hemiellipsoidal end caps. A stack of identical capsular articles according to the teachings herein may fill very well an inner housing, having cylindrical sides with a convex head at one erfd and a concave head at the. other end. Such an inner housing may have a design similar to an aerosol spray can. The recess formed by the concave head may advantageously be. filled with one or rriore HTF tubes. At one end of the inner housing, the curyature may be different than the curvature of the capsular article so that there is a gap in the cavity of the inner housing suitable for accommodating a compaction component _:for applying a compressive force to a stack of articles.. By way of example, a concave end of the inner housing may have a curvature that is lower than the curvature of an adjacent article. Such a spring may be employed to ensure that all the gaps By increasing or maximizing the deyice-level fill ratio, the HSD employing a capsular article according to the teachings herein may be particularly suited for use Filed Via EFS @ USPTO.gov on 04-06^2012

Attorney Docket No, 70928 (1062-1.77WO)

in vehicles, such as vehicles where the space available for a HSD is limited.

[41] The capsular article generally has.a first outer- radial surface that is generally concave and ah opposing second radial outer surface triat is generally convex. The spacing between the first outer surface and_: the second outer surface is the thickness dimension of the capsular article. The space between the two radial outer surfaces includes one or more TES s. The TESM is' generally isolated in one or more sealed spaces. The thickness direction is generally a small dimension of the article. The article is arranged to form one or more passages in the article which are generally transverse to the concave and convex radial surfaces. The passages preferably allow a fluid, such as a heat transfer fluid to flow. A passage may function to allow a path for a heat transfer fluid to.flow between a location above the article and a location below the article without having to flow around the article. The capsular article may have an outer periphery region defined by the regions of the article that are furthest from the opening. The radial outer surfaces generally extend partially or entirely from the one or more .opening of the article to the outer periphery of the article. The capsular article may .^'have a axial direction that is defined by the direction normal to the opening. It will be appreciated that the direction of the thickness will vary due to the curvature of the first and ..second outer surfaces. If the first and second outer, surfaces have generally the same curvature, then the value of the thickness will, also vary (e.g., the thickness may be a function: of the radial distance from the axis of the opening.

[42] The capsular article may have; one or more fluid passages (i.e. openings). Preferably the. capsular article has. one fluid passage. The one or more fluid passages may allow a fluid, such as a HTF to flow through the article without contacting the TESM. The. fluid passage, the cross- sectional area of the fluid passage, preferably is sufficiently large so that the HTF can flow through it with minimal loss in pressure. The fluid passage may be located in any location in the capsular article and preferably is near or includes the geometric center of the capsular article. A fluid passage may be at or near an apex of the capsular article. A fluid passage that is near or includes the geometric center of the capsular article may allow the article to be employed in a device where sortie or all of the fluid paths in the device have substantially the same flow length and/or substantially the same hydraulic resistance, such as characterized by a Tichelmann system.

[43] The fluid passage may be of any cross-sectional shape that facilitates passage of fluid through the capsular article. Without limitation, the fliiid passage may have an axial direction and a cross-section of the fluid passage with a plane normal to th axial direction may any shape that facilitates flow of a fluid through the passage without flow reduction such as back flow and may preferably be generally circular, generally polygonal, or generally oval shaped. Preferably, the fluid passage has a generally cylindrical shape. For example the fluid passage may have an axial direction and the cross-section of the fluid passage with a plane normal to Filed Via EFS @. USPTO.gov on 04-06-2012

Attorney Docket No. 70928 (1062-177WO)

the axial direction may be generally circular.

[44] The length of the fluid passage (e.g., in the axial direction) may be any length that allows for efficient heat transfer and preferably is the thickness of the capsular article. The size of the fluid passage is a measure of the diameter of the fluid passage for a fluid passage having a generally cylindrical shape, or twice the shortest distance from the center of the opening to any surface of the capsular artjcle. The size of the fluid passage is preferably greater than about 0.1 mm, more preferably greater than about 0.5 mrri, even more, preferably greater than about 1 mm, and most preferably greater than about 2 mm so that a fluid can flow through the opening. The size of the fluid passage may be sufficiently small so that the fluid passage does not occupy a large volume of space. Preferably the fluid passage has a size less than about 20 mm. For example, the fluid passage may have a generally circular cross-section with a radius that is preferably less than about 10 mm:

[45] A capsular article according to the teachings herein (e^g,,- having a generally dome-shape) may be partitioned into a plurality of sealed sector capsules (e.g., individually sealed compartments). A .capsular article having a plurality of sealed sector capsules may. be kept together as a. "capsule pack,'^! for example, by at least one continuous encapsulant sheet forming multiple capsules. Alternatively the capsular article may include a plurality of separate or separable segments (e.g., each containing one or more sealed sector capsules) that together form the capsular article having a first outer radial surface that is generally concave, an opposing outer radial surface that is generally convex, and a fluid passageway capable of allowing a fluid to flow between the outer radial surfaces.

[46] It will be appreciated that a capsular article having one or more sealed spaces 28 and a fluid passage 16 may be formed from a single component (e.g., a single inseparable component) having a fluid-passage 16, such as shown in the article 10 illustrated in FIG. 1A, or by assembling and/or arranging a plurality of segments 50 which together provide generally the same shape, such as the capsular article 10' illustrated in FIG. 2A. As such, a layer of ca'psules, including one or more sealed spaces, may be provided by a single segment or by a plurality of segments 50. A capsular article may advantageously be provided by a plurality of segments so that the stresses in the structure (hoop stresses, or otherwise) are reduced or eliminated. A capsular article may advantageously be provided by a plurality of segments so that a failure (e.g., a leak or puncture) of a sealed space results in a reduced loss of TESM. Alternatively, an article may be a single inseparable component that includes a plurality of sealed spaces 28 such as the capsular article illustrated in FIG. 2C. If the capsular article is formed by a. plurality of sealed spaces and/or segments, the number of sealed spaces or segments may be two or more,, or about six or more. The number of sealed spaces a d/or segments preferably is about 100 or less and more preferably about 20 or. less. It will be appreciated that more than 100 segments may be employed when the capsular article is greater than about 500 mm in one, or Filed Via EFS @ USPTO.gov on 04^06-2012

Attorney Docket No. 70928. (1062-177WO)

more directions, or when it is desired to have the TESM into small spaces. A segment of a capsular article, such as the segment 50 of a capsular article 10' Illustrated in FIGs. 2A and 2B, may have a convex outer radial surface 54 and an opposing concave outer radial surface 55 that respectively forms a portion of the generally convex radial outer surface 4 and the generally concave outer radial surface 6 of the capsular article.._.A segment 50 may have an outer edge surface 58 that becomes a portion of the. outer edge, surface 30 of the capsular article. A segment 50 may have an opening edge surface 56 , that forms a portion of the opening edge surface 32 of the capsular article. A segment 50 may have one or more lateral edges 52 that each mate with a lateral edge 52 of an adjacent segment 50. As illustrated in FIG. 2A and 2B, ^•the article may resemble an arrangement of bananas naturally configured around a central axis.

[47] When the capsular article includes a plurality of individually sealed spaces, two or more of the individually sealed spaces may include the same TESM or may include two or more different TESMs. Preferably, all of the segments in the capsular article have the same TESM.

[48] When the capsular article includes a plurality of segments, two or more of the segments may include segments having the same shape, the.same volume, the same thickness, or any combination thereof. However, segments having different shape, different volume, or different thickness may also be employed. When a capsular article includes two or more segments, it may be necessary to arrange the segments so that fluid flow between the lateral edges of adjacent segments, is reduced, minimized, or even eliminated. For. example adjacent segments may have lateral edges that generally mate so that the gap between the segments is not too large. It will be appreciated that some flow of HTF between adjacent segments may be desirable to ;the extent that the rate of heat flow from the article is increased.

[49] The capsular article may be formed from a first sheet and a second sheet that both include one or more openings. The sheets are preferably arranged so that at least one opening of the first sheet overlaps at least one opening of the second sheet. As such, the sheet^'s have one or. more corresponding openings: Each sheet has an outer periphery in the regions furthest from the center of the sheet. Each sheet has one or more opening peripheries in the region(s) of the: sheet near an opening, which preferably is near the center of the sheet. The two sheets may be sealingly attached to each other or to one or more other optional sub-structures (such as an outer ring) along the respective outer peripheries of the; sheets, for forming one or more sealed spaces therebetween. The two sheets may be sealingly attached to each other or to one or more other optional sub-structures (such as an inner ring) along the respective opening peripheries of the sheets, for forming one or more sealed spaces therebetween. Preferably the sheets are sealingly attached to each other along their respective outer peripheries, along at least one of their respective corresponding opening peripheries, or both. Most preferably the two sheets are sealingly attached to each other both along their respective outer peripheries and along at least one of their respective, corresponding opening peripheries. It will be Filed Via EFS @ USPTO.gov on 04-06-2012

Attorney Docket No. 70928 (1062-177WO)

appreciated that the sheets may also be sealingly attached to each other or to one or more other optional sub-structures along one or more additional regions other than their outer and opening peripheries so that a plurality of sealed spaces are formed.

[50] The capsular article may have one or any combination of the features of the . capsular article illustrated in FIGs. 1A, B, 1 C, and ID. FIG. 1A is a perspective view of an illustrative capsular article 10 showing a top surface (e.g., a radial surface having curvature 1 1 ). The top surface may be a generally convex, outer radial surface 14. The generally convex outer radial surface 14 may be formed by a sheet 4 having a convex surface and an opening 7. The article has an opening 16, such as an opening near the center of the article. The axial direction of the article may be the direction normal to the opening -16. The article 10 has an outer periphery 9 in the region that is generally furthest from the opening.. The article 10 may have a generall dome-shape, such as illustrated in FIG. 1A. FIG. TB is a perspective view of the article of FIG. 1A showing the bottom of that article 10. The article. 10 bottom surface is a.radial outer surface

1 1 having curvature. The bottom surface may be a generally concave outer radial surface of an article 12. The concave outer radial surface of the article ί 2 may be a surface of a first sheet 2 having a concave surface, The first sheet 2 may have an opening 6 and an outer periphery region 8. The first sheet has an opening periphery region 17 in the region of the first sheet 2 near the opening 6: FIG. 1 G is a diametrical cross¾ectional view of the article shown in FIG. 1 A: As illustrated in FIG: 1 C- the first sheet (e.g., a sheet having a generally concave outer radial surface) 2 and the second sheet (e.g., a sheet having a generally convex outer radial surface) 4, may be sealingly attached 26 along the outer periphery of the. sheets 8, 9, may be sealingly attached 26 along the opening periphery, or preferably both. The article 10 includes a TESM 5 in the space between the first sheet 2 and the second sheet. The TESM preferably is contained in one or more, sealed spaces 28. The article may have an outer edge surface 30 in the region of the outer periphery 18. The article may have an inner edge surface 32 in the region of the. opening 16. FIG. D is another diametric cross-section view of the article shown in FIG. 1 A. As illustrated in FIG. D, the article may have, an outer periphery 18 in the region furthest from the opening 16 of the article 10 and an opening periphery 17 in the region near the opening 16 of the article 10. The article may have: a separation distance 46, x, between the generally radial outer surfaces 12, 14, in the axial direction 41. The. article may have a height* h, 40, which is the difference, along the axial direction 41 , between the location of the concave outer radial surface

12 near its outer periphery and the location of the concave outer radial surface near its inner periphery. The longest dimension 45 of the article 10 may be the diameter of the- circular projection of the axial projection of the article.

[51] The thickness of the capsular , article is the distance between the opposing outer radial surfaces. Advantageously, the thickness of the article may decrease going from a region near the opening of the article to a region near the periphery of the article. Such a decrease in the Filed Via EFS @ USPTO.gov on 04-06-2012

Attorney Docket' No. 70928 (1062-177WO)

thickness may allow for increased power of the HSD by reducing the distance for heat to travel (e.g., from the mid-thickness ^"of the article to the^' surface of the article). A low thickness is preferred toward the outer periphery region of the article because the HTF in that region, during a process of removing heat from the article, will have a higher temperature and thus a lower driving force for thermal conduction. FIG. 3A is a cross-section of the article of FIG. 1 D in a region near the outer periphery of the article and FIG. 3B is a cross-section of the article towards the opening. With reference to FIG. 3A, the article has ah axial direction 41 and a radial direction 43 perpendicular to the axial direction. The separation distance, x, between the opposing outer radial surfaces in the axial direction may be generally constant so that the articles a plurality of the articles can be easily stacked. The thickness 42' of the article is defined by the distance between the two opposing outer radial surfaces at a given location. In the regions near the outer periphery, the article has a relatively high slope, as illustrated by the angle a' 44'.. The thickness can be calculated at this position as f =x cos al. With reference to FIG. 3B, in the region that is less sloped (having an angle a 44), the thickness is calculated as t=x cos a. Because the surface has a greater slope relative to the radial direction in FIG. 3A, the thickness in FIG. 3A is less than the thickness in FIG. 3B.. ln other words, if 0°≤ a < a' < 90°, then x cos ' < x cos .a, and t' < t

[52] The capsular article may optionally include one or more sub-structures that when sealingly attached to a first sheet and a second sheet forms one or more sealed spaces. The one or more sub-structures may be employed to form one or more walls which separate one or more sealed spaces from a HTF and/or to form one or more walls which separate two sealed spaces. Suitable sub-structures that may be used in the capsular article include those that are described in PCT Publication WO2011/094371 , published on August 4, 2011 and in U;S.. Patent Application Publication 2009/025018, published on October 8, 2009, both incorporated herein by reference. For example, the capsular article may include a ring„.a honeycomb structure, or both. Preferred substructures have a wall thickness sufficiently large so that it can be sealing attached to a sheet. Preferred substructure preferably has a wall thickness that is sufficiently small so that the weight of the substructures is less than the. weight of the sheets.

[53] The thickness of the capsular article is defined by the separation between the generally concave outer radial surface and the opposing generally convex outer radial surface. The article may have a geometry, so that heat can rapidly be provided from a fluid to the TESM and/or rapidly removed from the TESM to a fluid. For example, the article may be relatively thin (e.g., compared with the length or diameter of the article). Preferably; the average thickness of the article is less than about 80 mm, more, preferably less than about 20 mm, even more preferably less than about 10 mm and most preferably less than about 5 mm. The average thickness of the article preferably is greater than about 0.5 mm, more preferably greater than about 1 mm.

[54] The longest dimension of the capsular article, may .defined as the longest dimension of any Filed Via EFS @ USPTO.gov on 04-06-2012

Attorney Docket No. 70928 (1062-177WO)

projection of the article onto a plane. For example, the longest dimension of the dome-shaped capsular article illustrated in Fi<3. 1 A is the diameter of the base of the dome, as represented by the axial projection of the article onto a plane perpendicular to the opening axis. The longest dimension of the article is typically much greater than the thickness of the article so that the article can both have a large volume (e.g., for containing a large volume of TESM), and a large surface area (e.g., for rapid transfer of thermal energy). The longest dimension of the article preferably is about 30 mm or more, more preferably about 50 mm or more and most preferably about 100 mm or more. The longest dimension is defined by the use, and can be any length that meets the need for heat storage, heat transfer, or both, in a particular use. The longest dimension of the article typically is about 2 m or less, however articles having a longest dimension greater, than about.2 m may also be employed. The ratio of the longest dimension to the average thickness is preferably about 5 or more, more preferably, about 10 or more, even more preferably about 20 or more, and most preferably about 30 or more: The ratio of the longest dimension tip the average thickness typically is about ^!100 or less, but may be higher.

[55] The article may have one or more outer periphery edge surfaces. For example the article may have one or more outer periphery edge surfaces that are nonplanar. The article may have a single outer, periphery edge surface that is generally arcuate, generally nonplanar, generally continuous, or any combination thereof. Preferably the one or more outer periphery edge surfaces are generally equidistant from a center of the article so that the article can be placed in a container (e.g., .an insulated housing ha ing a generally cylindrical cavity with a cavity diameter that is only slightly larger than the average distance ^'from the outer periphery edge: surface to the center of the article as projected on a plane perpendicular to the opening axis (i:e., the center axis-outer periphery, distance). When the ratio of the cavity diameter to the center axis-outer periphery distance of the article is low; a large amount of the cavity, may be occupied by the article. For example, the ratio of the cayity diameter to the center axis-outer periphery distance diameter of the article may be about ,8 or less, preferably about 1.2 or less, more preferably about 1.1 or less, and most preferably about 1.05 or less. It will be appreciated that the ratio of the cavity diameter to the center axis-outer periphery .distance of the article is. typically at least about 1.0 (e.g:, about 1 :001 or more):

[56] A large portion of the volume of the capsular article is the encapsulated volume (i.e. the volume inside the walls of the one or more sealed spaces) so that the article may contain a generally large amount of the TESM. The total encapusulated volume of the article, the total, volume of the TESM, or both, is preferably about 50 volume percent or more, more preferably about 80 volume percent or more; even more preferably about 85 volume percent or more and most preferably about 90 volume percent or more based on the total volume of the article. The. total encapsulated volume of the article, the total volume of the TESM, or both is typically about 99.9 volume percent or less based on the total volume of the article. The remaining volume, not Filed Via EFS @ USPTO.gov on 04-06-2012

Attorney Docket No. 70928 (1062-177WO)

occupied, by the TESM, may include or consist substantially entirely of the walls of the article (e.g., the first and second sheets, and any substructures according to the teachings herein), void spaces (e.g., containing one or more gases), one or more heat conducting features or elements for improving the heat transfer between the TESM and a wall or outer surface of the article, or any combination thereof. Suitable heat . conducting elements / features include any element or feature in the sealed space that is formed of a material haying a . relatively high thermal conductivity (e.g., relative to the TESM) and is capable of increasing the rate of heat flow from the TESM to an outer surface of the article (.g„ and then to a HTF). Examples of heat conducting features and heat conducting elements include- fins, wire mesh, protrusions into the sealed space, and the like. Without limitation, suitable materials for a heat conducting element include graphite, copper, aluminum, steel, or any combination. The material may be coated (e.g. for corrosion prevention) or uncoated; Preferably, the heat conducting elements are oriented for increasing or. maximizing the rate of heat flow between the TESM and an outer radial surface.. For example, an element may be oriented generally perpendicularly to the opposing concave and convex outer radial surfaces (e.g., the. radial outer surfaces) of the article. An exemplary element is a wire or ribbon that is first coiled and then bent into a. spiral, such as the axial projection of a spiral illustrated in FIG. 12G. The .concentration of the heat conducting element, if employed should be sufficiently high so that the average, or effective thermal conductivity of the material sealed in the walls of the container (e.g., the . average of thermal conductivity of the_; TESM and the heat conducting element) is increased by about 50% or more, by about 100% or more, by about 200% or more, by about 400% or more, or by about 1000% or more (e.g., compared with the thermal conductivity of the TESM). The volume of the heat conducting element in the article, if employed, may be about OA volume % or more, about 1 volume % or more_t about .2 volume % or more, or about 5 volume % or more, based on the total encapsulated volume of the capsular article. The concentration of the heat conducting element preferably is sufficiently low so that the heat storage density of the article increases changes by- about 20% or less. The concentration of the heat conducting element preferably is about .30 volume % or less, more preferably about 20 volume % or less, and most preferably about 10 volume % or less, based ori the total encapsulated volume of the article. FIG. 9 is an illustrative^, cross-section of an article 10 having a heat conducting element 48, encapsulated in a sealed space. The heat conducting element 48 may be partially or. entirely surrounded by the TESM 5. The A coiled heat conducting element may have a pitch, such as illustrated in FIG. 12A and FIG. 12B. Preferably the pitch is smaller than the average thickness of the capsular article, so that the distance for heat flow in the TESM to a heat conducting element is generally low. For example, the ratio of the pitch of a coiled heating element to the average thickness of the article may be about 0,9 or less, about 0.5 or less, or about 0.3 or less. The heat cpnducting element increases the heat flow and will be distributed in the sealed space in the regions which require Filed Via EFS @ USPTO.gov on 04-06-2012

Attorney Docket No. 70928 (1062-177WO)

an increase in heat flow. Although the element may be preferentially located in the regions towards the outer periphery (e.g., closer to the outer periphery than the opening periphery), it may be advantageous to have the heat conducing element distributed_, throughout the entire encapsulated volume so that heat flow is further increased. A coiled wire heat conducting element may have an axial projection . that is generally circular, such as illustrated in FIG. 12B. The axial projection of the coiled wire may have any shape, such as ah elliptical, an oval, a polygon, a rounded polygon (e.g., a rounded rectangle) or other suitable shapes. The axial projection of the .coil may have a geometry having a long axis and a short axis (e.g. , having an aspect ratio of about 1.1 or more, about 1.5 or more, or about 2.0 or more). If the axial projection has a long axis (such as a generally elliptical coil), the orientation of the long axis is preferably is generally perpendicular to the radial surfaces of the capsular article. Another heat conducting element that may be employed is a foil that has been perforated and stamped so that it has. fins: protruding in at least one, and preferably both directions. Such a foil may also be corrugated. The foil should be sufficiently thin so that ;fhe volume of the heat conducting element is low, such as described. erein before. The heat conducing element may be.a foil 48"' having one or any combination of the features illustrated in FIG. 12C. The heat conducting element, whether a coil, a foil, or otherwise, may be arranged in the sealed space so that the element contact or e or both opposing Walls of the article.

[57] The article preferably is easy to stack with other identical shaped articles, or other articles having a generally mating surface. For example, two articles to be stacked may have opposing surfaces that are generally mating surfaces so that when stacked, the two articles nest together, it will be appreciated that one approach for stacking articles so that they easily nest together is to select a shape having a rotational symmetry of a high order. The rotational symmetry may be about an axis in the stacking direction (e.g., an axis through the fluid passage of the capsular structure). The order of the rotational symmetry typically describes the number of distinct rotations between the' two surfaces being stacked together in which they will nest together. The. order of the rotational symmetry of the article preferably is at: least 2, more preferably at least 3, even more preferably at least 5, and most preferably at least 7.

[58] In a particularly preferred embodiment of the invention, adjacent articles do not entirely nest together. For example, a radial surface of .one article may be in contact with a radial surface of another article, where at least one of the surfaces has a secondary texture, that is secondary to the generally convex or concave shape, so.that the surfaces only partially contact.

[59] Orie or both contacting radial surfaces of a pair of stacked articles may have one or more radial grooves or radial channels (i.e., a groove or channel that has a radial .component that includes a projection along a radial direction), that preferably extends from about the center opening to the outer periphery of the article). Suitable radial grooves and channels may be sufficiently deep and/or sufficiently wide so that they allow a space for a HTF to flow. In addition Filed Via EFS @ USPTO.gov on 04-06-2012

Attorney Docket No. 70928 (1062-177WO)

to having a radial component, a groove or channel may have a tangential component (i.e., the orientation of at least a portion of the groove or channel includes a projection onto the tangential direction). For example, a groove or channel may have a spiral shape that includes both a radial component and a tangential component. Two sheets of adjacent articles that are in contact preferably have grooves and channels with tangential components that are different (e.g., having different directions and/pr different magnitudes). The tangential components of adjacent sheets preferably are sufficiently different so that the fluid streams flowing between adjacent sheets in different grooves at least partially mix due to differences in their velocity vectors. Advantageously, one sheet may have grooves or channels with a tangential component in. the clockwise direction and the adjacent sheet may have grooves or channels with a tangential component in the counterclockwise direction, so that the fluid flowing between the two layers at least partially mixes when grooves intersect (e.g., when two streams of fluid flowing in the grooves of two adjacent . capsular article come info direct .contact for less than their entire flow paths). FIG. 4A is a perspective drawing of an illustrative capsular article 10 having a generally convex outer radial surface with a secondary structure 38 and a generally concave outer radial surface with a different secondary structure 38'. With reference to: FIG. 4A,. the secondary structure 38, 38' may include.a plurality of radial. grooves having valleys 32 and ridges 34. Such valleys.and ridges may generally extend between the opening of the structure 16 and the exterior periphery 18 of the- article 10. The grooves may have one. or any combination of the following features: the grooves may be curved, the grooves may be curved so that they have a tangential component, the grooves may be uniformly spaced, adjacent grooves may have the same, length, the grooves may have a spiral shape, and adjacent grooves may provide flow paths generally having the same hydraulic resistance. When viewed from above the generally convex outer radial surface, an article may have one outer radial surface that has a clockwise tangential component and the other may have a counterclockwise tangential component. FIG. 4B is an. illustrative top view showing a sheet 4 of a capsular article 10 having a plurality of clockwise grooves extending from an opening 16 to an outer periphery. An outer radial surface that has a non-circular axial projection may. have. a secondary structure 38 that includes grooves that form a plurality of valleys 32 and ridges 34. With reference to FIG. 4B, the axial projection of the outer radial. surface of a sheet may be a shape that is a generally rounded polygon, such as a rectangle having rounded corners.

[60] The axial projections of the capsular article may be generally circular in shape, such as the axial projections of the outer radial surfaces 12, 14 illustrated in FIGs. 1A and 1 B. Other shapes for the axial projections of the outer radial surfaces of the capsular article are possible and may even be desirable. For. example, the capsular article may be employed in a HSD that is required to fit in a tight space, such as under the hood or under the floor of a vehicle. Although a cylindrical shape may be advantageous for reducing surface area, other more elongated, boxy Filed Via EFS @ USPTO.gov on 04-06-2012

Attorney Docket No. 70928 (1062-177WO)

or suit-case like shapes may be advantageous for fitting into an available space. It will be appreciated according to the teachings herein that the generally circular shaped axial projections of the outer radial surfaces of the capsular article may advantageously be replaced with shapes that are not circular. As such, the capsular article may have axial projections of outer radial surfaces having- a shape similar to the shape of a cross-section of a container that can fit into the desired space. The-shape may be a generally symetrical shape or a shape that is irregular or assymmetrical shape. Examples of generally symmetrical shapes- include an oval shape, an elliptical shape, a circle, a rounded polygonal shape, and a; polygonal shape (e.g., a rectangular shape, a square shape, or a hexagonal shape). For example, an axial projection of the. surface may have a generally rectangular shape with rounded corners. FIG. 4B is a top view of an outer radial surface having an axial projection that_, has an elongated shape, such as a generally elliptical shape. The axial projection of the^opehing of the article may be any shape. The axial projection of the, opening and the axial projection an outer radial surface may have shapes that are similar (but .different, size) or may have shapes that are different (such as a generally circular opening and a noncircular outer periphery). As' illustrated in FIG. 7, the axial projections of the opening and of the outer radial surface may generally have the same shape.

[61] All of the TESM of the article may be in a single sealed space. Preferably the TESM of the article is divided; between a plurality of sealed spaces (i.e., individually sealed spaces) so that if a sealed space is punctured or otherwise leaks, only a portion of the. TESM can be removed. As such, the number of sealed spaces in the article (e.g., sealed spaces that contain TESM). is preferably at least 2, more preferably at least 3, and even more preferably at least about 5. The upper limit on the number of sealed spaces is practicality and for a particular application is- defined by the need of the applicatiqn. Nevertheless, the number of sealed spaces in the article typically is less than 1 ,000. However; it will be appreciated that very large articles may have 1 ,000 or more sealed spaces. For the same reasons, the volume fraction of the TESM that is found in any single sealed compartment preferably is less than about 55%, more preferably less than about 38%, even more preferably less than about 29%, and most preferably less than about 21 %, based on the total volume of the TESM in the article. Typically a sealed space includes at least 0.1 volume % of the. TESM in the article. However, it will be appreciated that the article may include one or more sealed spaces that are substantially or even entirely free of the TESM. FIGs. 2A, 2B, and 2C illustrate features of articles with a plurality of sealed spaces.

[62] The individually sealed spaces may optionally be arranged in a single ring such as illustrated in FIG. 2C so that the symmetry of the article may be generally high for ease of assembly. The sealed spaces may optionally be arranged in a plurality of concentric rings, including an innermost ring (e.g., a ring closest to the opening periphery) and an outermost ring (e.g., a ring closest to the outer periphery), each containing one or more sealed spaces. The sealed spaces in one ring may have a generally repeating pattern. The number of sealed Filed Via EFS @ USPTO.gov on 04-06-2012

Attorney Docket No. 70928 (1062-177WO)

spaces in each ring may be the same or different.

[63] As discussed hereinafter, the article¹ may be placed in a container a cavity that is only slightly greater in dimension than the longest dimension of the article. For example, the diameter of the cavity of a cylindrical container may be only slightly larger than the diameter of the. axial projection of an article having a generally dome shape. The cross-section of the cavity should be sufficiently large so that the article can be inserted into the cavity. When the article (or a stack of the articles) is placed in the container, it may be desirable^'for a fluid to be capable of flowing between the outer periphery of an article and an interior wall of the container. Such flow may also be achieved using indents in the outer periphery of the article and/or grooves or channels along the inner wall of the container. Examples of indents and . grooves that may be used include those described in PCT Publication W02Q.11/094371 , published on August 4, 2011 , incorporated herein by reference. One or both encapsulent sheets may optionally have a spacing feature capable of spacing adjacent articles, so that when a first article is stacked with another article having a surface that generally mates with first article, the two articles only partially nest. As such the spacing features may function as a spacer to separate the generally mating surfaces so that a fluid (e.g., a HTF) can flow between the^mating surfaces_^ Stacking of articles and other spacing: means are discussed hereinafter.. If employed, the spacing feature, preferably cover only a small portion of an outer radial surface.

[64] A further aspect of the present invention is an integrated static mixer or a static mixing element that will sufficiently promote mixing of a HTF so that the need for a secondary texture or feature (such as spiral grooves having ridges and valleys) on the outer radial surfaces of the article is reduced or eliminated: The integrated static mixer may include a plurality of features capable of dividing and/or perturbing the flow of the HTF, exemplary features include bumps or protrusions that are stamped into one or both outer radial surfaces of an article. The integrated static mixing may include an array of such features. The, features should extend sufficiently into the gap between two adjacent articles so that they promote mixing of a HTF. The number of features should be sufficiently high so that the radial flow of a substantial portion of the HTF is divided and/or redirected one or more times. Preferably, the features are arranged in. a staggered array. Such an array may have a particularly good ability to promote heat exchange between the article's radial outer surfaces and the HTF. Mixing of the HTF flowing between two capsular articles may be provided by a static mixing element that is positioned in the gap between the two articles. The static mixing element may be formed from a structure that is sufficiently thin so that.it can be placed between two capsular articles^'.while allowing the spacing between adjacent articles to be generally low for maintaining a high concentration of TESM (e.g., in an inner housing, or in a HSD). The static mixing element may be in the form of a sheet that is a woven, such as braided, or knitted,,or a non-woven, such as a wire, a ribbon mesh, or or foil. The static mixing element may be sufficiently porous so that portions of the HTF can Filed Via EFS @ USPJO.gov on 04-06-2012

Attorney Docket No. 70928 (1062T177WO)

alternate between flowing above and flowing bellowing the mid_^plahe of the element. The static mixing element preferably has a curvature similar to the curvature of the outer radial surfaces so that it can be easily placed between the two -articles without large stress or strain. As such, the static mixing element may have a generally dome-shape.. The static mixing element may be used to define the spacing between adjacent articles. The static mixing element may be made of a material sufficiently rigid at a melting temperature of the PCM, so that the static mixing element generally maintains it shape during thermal cycling of a HSD (e.g., charging and discharging). This separation distance between the adjacent articles may provide a desired thickness of a channel for flowing the HTF. According to the teachings herein, a stack of articles may be forced together using one or more compaction components. The static mixing element should function (e.g., to provide spacing, rigidity, or both) under the force of such a component. In addition to separating two articles, the element may function as a turbulator or a static mixer.

[65] The static mixing element or integrated static mixer may sufficiently promote mixing of the HTF across the thickness of the flow channel, so that the power of the HSD is increased. Preferably, such a component increases the power of the HSD by about 2% or more, by about 5% or more, by about 20% or more, or by about 50% or more. The component may function by increasing the rate of heat transfer from the surfaces of the capsular article and the HTF. If a foil is employed, it preferably includes^" features that. ermit flow from one side of the foil to the other, such as opening and/or features capable of dividing a stream of flow, such as a protrusion. The features may be stamped into the foil. Examples of that may be stamped into a foil include, slits, slots, fins, blades, and curved surfaces. The static mixing element may include protrusions extending upward, protrusion that extending downward, or preferably both. For example, the upward and/or downward protrusions may be used to define the spacing between adjacent articles. An example of a protrusion, that may be used is the generally ¼ spherical shape typically seen protruding on a cheese grater surface. Such protrusions may be on both sides of the' foil sheet. The thickness of the foil sheet used for the static mixing element may be about 3 mm or less, about 1 mm or.less, about 0.5 mm or less, about 0;2 mm or less, or about 0.1 mm or less. The static mixing element preferably is made of ^' a . material having generally high thermal conductivity, so that heat transfer from the articles is increased, so that a more uniform temperature of the HTF is maintained through; the. thickness of the flow, or both. The static mxing element may be made of a material having a heat distortion _. temperature greater than the melting temperature of the PCM. Examples of suitable materials include metals such as aluminum, copper, and steel. The static mixing element may be formed from a sheet by forming a plurality of spaced apart slits and stamping the material on one side of the slit to form a downward protrusion and stamping the material on the other side of the slit to form an upward' protrusion. When viewed from the top, the material on one side: of the slit is generally concave and the material on the other side of the slit is generally convex, and thus may be referred to as Filed Via.EFS @ USPTO.gov on 04-06-2012

Attorney Docket No. 70928 (1062-177WO)

"janus slits." The static mixing element preferably has a large number of tightly spaced janus slits. In the direction of flow, a forward facing janus slit is generally followed by a backward facing janus slit and vice versa. An example of a static mixing element 49 positioned between two adjacent articles 10 is shown in is shown in FIG 10. The static mixing, element. The static mixing element preferably is used in the region of the radial flow of. the HTF. However, a static mixing element may also be used an axial flow of the HTF. With reference to FIG. 10, the static mixing element preferably .extends oyer the entirety of the. two radial outer surfaces. The static mixing element preferably contacts both a generally concave radial outer surface and a generally convex radial outer surface. Static mixing elements may include features that can redirect and/or divide the flow of a fluid, . such as features in the static mixing element illustrated in FIG. 11 A (a top view of the mixing element) and FIG- 11 B (a cross-section of the static mixing element from a side view). For example, the static mixing element 49 may be permeable and include a plurality of openings 126 that allow a HTF to cross between the sides of the element. The static mixing element may include regions that are generally in the mid-plane 128 of the element. The static mixing elements may include a plurality of protrusions or other features that extend upward 122 from the mid-plane 128, protrusions that extend downward 124 from the mid-plane. 128, or preferably both. As viewed from the top, the static mixing element may have regions on one side of the openings that are generally concave 125 and regions on the other side of the openings that are generally convex 123. Such openings may be "janus' slits", such as described hereinbefore. The distance between the peaks of the upward projections 122 and the valleys^; of the ^"downward projections 124 may define the gap thickness (i.e. , the thickness of the gap between two adjacent articles).

[66] Without limitation, Suitable TESMs for the HSD include materials that are capable of exhibiting a. relatively high .density of thermal energy as sensible heat, latent heat,, or preferably both. The TESM is preferably compatible with the operating temperature range of the HSD. For example the TESM is preferably a solid at the lower operating temperature of the HSD, is at least partially a liquid (e.g., entirely a liquid) at the maximum operating temperature. of the HSD, does not significantly degrade or decompose at the maximum operating temperature of the device, or any combination thereof. The TESM preferably does not. significantly degrade or decompose when heated to the maximum operating temperature of the device for about 1 ,000 hours or more, or even for about 10,000 hours or more. The TESM may be a phase change material having a solid to liquid transition temperature. The solid to liquid transition temperature of the TESM may be a. liquidus temperature, a melting temperature, or a eutectic temperature. The solid, to liquid transition temperature should be sufficiently high so that when the TESM is at least partially or even substantially entirely in a liquid state enough energy is stored to heat the one or more objects to be heated to a desired temperature. The solid to liquid transition temperature should be sufficiently low so that the HTF, the one or more objects to be heated, or Filed Via EFS @ USPTO.gov on 04-06:2012

Attorney Docket No. 70928 (1062-177WO)

both, are not heated to a temperature at which it may degrade. As such the desired temperature of the solid to liquid transition temperature may depend on the object to be heated and the method of transferring the heat. For example, in an application that transfers the stored heat to an engine (e.g., an internal combustion engine) using a giycol/water HTF, the maximum solid to liquid transition temperature may be the temperature at which the HTF degrades. The solid to liquid transition temperature may be greater than about 30 °C, preferably greater than about 35 °G, more preferably greater than about 40 °C, even more preferably greater than about 45 °C, and most preferably greater than about 50 "C. The. TESM. may have a solid to liquid transition temperature less than about 400°G, preferably less than about 350°G, more preferably less than .about 290°C, even more preferably, less than about 250°C, and most preferably less than about 200°C. For some applications, such as transportation related applications, it may desirable for the thermal energy material to efficiently store energy in a small space. As such, the TESM may have. a high heat of fusion density (expressed in units of megajoules per liter), defined by the product of the heat of fusion (expressed in megajoules per kilogram) and the density, (measured at about 25 - C and expressed in units of kilograms per lliter). The TESM may have a heat of fusion density greater than about 0.1 Mj/liter, preferably greater than about 0.2 MJ/liter, more preferabl greater than about 0.4 MJ/liter, and most preferably greater than about 0.6 MJ/liter. Typically, the TESM has a heat of fusion density less, than about 5 MJ/liter However, TESMs haying a higher heat qf fusion density may also be employed-: It may be desirable for the, TESM to be light weight. For example, the TESM may have a density (measured at about 25°C) less than about 5 g/cm³, preferably less than about .4 g/cm³, more preferably less than about 3.5 g/cm³, and most preferably less than about 3 g/cm³. The lower limit on density is practicality. The TESM may have a density (measured at about 25°C) greater than about 0.6 g/cm³, preferably .greater than about 1.2 g/cm³, and more preferabl greater than about 1.7 g/cm³. The sealed spaces may contain any art known TESM. Examples of TESMs that may be employed in the TESM compartments include the materials described in Atul Sharma, V.V. Tyagi, C.R Chen, D. Buddni, "Review on thermal energy storage With phase change materials and applications ", Renewable and Sustainable Energy Reviews 13 (2009) 318-345, and in Belen Zalba; Jose Ma Mann, Luisa F. Cabeza, Harald Mehling, "Review on thermal energy storage with phase change: materials, heat transfer analysis and applications", Applied Thermal Engineering 23 (2003) 251-283, both incorporated herein by reference in their entirety. Other examples of suitable TESMs that may be employed in the heat , transfer device include the TESMs described in U.S. Patent Application No. 12/389,416 entitled "Thermal Energy Storage. Materials" and filed on February 20, 2009; and U.S. Patent Application No. 12/389,598 entitled "Heat Storage Devices" and filed on February 20, 2009. The TESM may include an organic material,, an .inorganic material or a mixture of an organic and an inorganic material that exhibits the solid to liquid transition temperature, the heat Filed Via EFS @ USPTO.gov on 04-06-2012

Attorney Docket No. 70928 (1062-177WO)

of fusion density density, or both,, described hereinbefore. Organic: compounds that may be employed include paraffins and non-paraffinic organic materials, such as a fatty acid. Inorganic materials that may be employed include salt hydrates and metallics. The TESM may be a compound or a mixture (e:g., a eutectic mixture) having a solid to liquid transition at generally a single temperature: The TESM may be a compound or a mixture having a solid to liquid transition over a range of temperatures (e.g., a range of greater than about 3^eC, or greater than about 5°C). Without limitation, the TESM may include one or more inorganic salts that includes one or more waters of hydration, one or more anhydrous salts, or both. The salt may include one or more anions selected from the group consisting of nitrate, nitrite, bromide, chloride, sulfate, sulfide, sulfite, carbonyl, phosphate, phosphate, hydroxide, and fluoride, one or more cations selected from the group consisting of potassium, iron, manganese, magnesium. sqdium, calcium, lithium, cobalt, zinc, and aluminum, or both.

[67] The volume of the TESM in the one or more sealed spaces of the article is sufficiently high so that the article can store a large amount of thermal energy. The ratio of. the volume of the TESM contained in the article to the encapsulated volume, the ratio, of the volume of the TESM to the total volume of the article, or both , (the volumes measured, at a temperature of about 25°C) may be about 0:5 or more, about 0.7 or more, or about 0.9 or more. The ratio of such volumes is typically less than about 1.0, and more, typically less than about 0.995. The sealed space may include a volume that contains a gas, such as air, N₂, or an. inert gas such as He, Ar_;, and the like, so that the TESM can expand when heated. The volume of a sealed space that is free of TESM (e.g., the volume of the sealed space that contains a gas) at 25°C, may be about 0.1% or more, about 1 % or more, or about 3% or more.

[68] FIG. 2C is a perspective view of an illustrative capsular article showing features of an that may be employed in a capsular article, such as a capsular article 10 having a plurality of sealed spaces 28. The capsular article may be formed by sealingly attaching two encapsulating sheets 2, 4 about an outer periphery and about ah inner periphery; The encapsulating sheets may be sealingly attached along a perimeter of one or more of the individually sealed spaces 28. Preferably the article is sealingly attached around the perimeter of each individually sealed space to form a primar seal, and is also, sealingly attached around the opening and outer peripheries of the sheets to form a secondary seal. As illustrating in FIG. 2C, the individually sealed spaces 28. may be arranged in a single ring (e.g. about the opening). It will be appreciated that the article may include sealed spaces arranged in a plurality of rings (e.g., a two or more cqncentric:rings). One or both of the sheets may include, lip regions 26 for sealingly attaching the sheets. For example, one or both sheets may include a. lip region around the perimeter of the sealed spaces, around the opening periphery, around the outer periphery, or any combination thereof.

[69] The articles containing the TESM preferably are capable of being stacked either with other Filed Via EFS @ USPTO.gov on 04-06-2012

Attorney Docket No, 70928 (1062-177WQ)

identical articles or with a second article having a generally mating surface. The articles may be stacked with a space between adjacent articles so that a HTF can flow between the articles. Features that may be used in a stack of article include those described in PCT Publication WO2011/094371 , published on August 4, 2011 , incorporated herein by reference. The flow of a fluid between facing surfaces of two adjacent articles will generally be in a radial direction and may be described as a generally radial flow. However, it will be appreciated that the flow will also have an axial component. The stack of articles will typically have a plurality of radial flow paths (e.g., 2, 3,.4, 5 or more). VVhen stacked, the articles preferably each have- at least one opening that corresponds with an opening from each of the other articles (except possibly an article at one end of the stack), so that a portion of a fluid can flow from a first article_;in the stack to a last article in the stack by flowing through each of the corresponding openings of the articles interposed between, the first and last article without flowing between adjacent articles (i.e,., without a generally radial flow). The flow through the openings, will generally be in an axial direction and may be described as a generally axial flow.

[70] FIG. 5 illustrates an aspect of the invention that includes a plurality of capsular articles 10, that are stacked. The articles 10 may be stacked so that their corresponding openings 16 are generally aligned in an axial direction 31. As illustrated in FIG. 6, the openings may provide an axial flow path 70 for flowing a HTF-. The flow of the HTF may be divided into a number of generally parallel of radial flow paths 72 (e.g., defined by the spaces between adjacent articles 10). Each radial flow path 72- preferably includes a radial component and an axial component. For example, the direction of flow in the radial flow path may include a direction that is a combination of a flow vector- in the radial direction and a flow vector in the axial direction. The direction of flow may also have a tangential component. The radial flow paths may recombine to form a.different axial flow path 74 (e.g., along the outer periphery walls of the articles).

Γ7_.1] The articles (e.g , a stack of articles) described herein may be employed in a HSD. The HSD may include one or more ,of the features, of the HSD described in PCT Publication WO2011/094371 , published on August 4, 2011.. incorporated herein by reference. The HSD may include a container or other housing having one or more orifices for flowing a HTF into the container and one or more orifices for flowing a HTF out of the container. The HSD may be characterized as having one or more HTF compartments. Preferably, the HSD includes a single HTF compartment. A HTF compartment may include or consist substantially of a contiguous space in the container between the inlet and the outlet, where the HTF can flow. The container preferably is at least partially insulated so that heat losses from the container to the ambient may be/educed or minimized.

[72] The HSD has an inner housing for containing the stack of articles. The stack of articles may be contained in one or more cavities of the inner housing.. Suitable inner housings may have one or more orifices (e.g., one or more inlets) for flowing a HTF into the cavity of the inner Filed Via EFS @ USPTO.gov on 04-06-2012

Attorney Docket No. 70928 (1062-177WO)

housing and one or more orifices (e.g., one or more outlets), for flowing a HTF out of the cavity of the inner housing. The inlet and the outlet may be on the same^'side or on different sides (e.g., opposing sides) of the inner housing. In a preferred arrangement, the orifices are on the same side of the inner housing. Other than the orifices,, the inner housing preferably is sealed or constructed so that a fluid flowing througrrthe housing does not leak out of the housing, so that a fluid flowing through the housing may have a pressure, greater than ambient pressure, _vor both.

[73] In general, the more that the. cavity of the inner housing matches the shape of a stack of articles to be placed in the housing, the higher will be the heat storage capabilities and/br the power capabilities of the HSD per unit volume of inner housing. A housing having a generally cylindrical shaped cavity (e.g. excluding the ends of the housing) may allow for efficient packing of articles having an axial projection that is generally circular. The inner housing may be employed to house a stack of the articles. The stack of articles is preferably arranged so that there is a central axial flow path (e.g., through the fluid passages of the plurality of articles). The central axial flow path preferably is at or near the axial center of the cavity of the inner housing. The axial projections of the articles may have a shape that is smaller than the axial projection of the cavity of the inner housing,, so that a HTF can flow in an axial direction between the outer peripheries of the articles. and the interior axial surface of the inner housing. Such a flow may be described as an outer axial flow. The stack of articles preferabl is arranged in the inner housing so thai the distance between the outer periphery of the articles and the interna! axial, surface of the inner housing is generally uniform for different outer periphery regions of an article, for outer periphery regions of different articles, or both.

[74] FIG.' 7 shows is a cross-sectional view of a portion of HSD including a stack of articles 10 arranged in an inner housing 80. The inner housing 80 has a generally cylindrical shape with axial side walls 85 that are generally aligned with, the. cylindrical axis of the inner housing. The inner housing 80 may have .one ends that are generally hemispherical, hemiellipsoidal, or haying another shape, with, curvature. Preferably the inner housing has opposing ends 82,. 84 where one end 84 has a generally concave inner cavity surface, and the opposing end 82 has a generally convex inner cavity surface. The cavity of the.inner housing 80 preferably has a shape similar to the shape of the stack of articles 10. The end 82 of the inner housing that has a generally convex inner surface, preferably has a curvature that generally mates with the concave outer radial surface 12 of the article. The end 84 of the inner housing that has a generally concave inner surface, may have a curvature that generally mates with the convex outer radial surface 14 of the article. Preferably, the end 84 of the inner housing that has a generally concave inner surface, has a curvature that is greater than the curvature, if the conve outer radial surface so that there' is space for the articles to expand when the temperature is increased (e.g., while charging the HSD with thermal energy). One or more springs 83 may be employed to provide a, compressive force on the stack of the articles. Such a spring may be Filed Via EFS @ USPTO.gov on 04-06-2012

Attorney Docket No. 70928 (1062÷177WO) .

used to provide a desired spacing between adjacent articles. Such spaced relationship_, may be maintained as the article is heated, so that a HTF can flow in the space between the adjacent articles. The stack of articles in the inner housing may have space for a HTF to flow through the inner housing. For example, there may be an axial flow path 70 through the openings 16 of the articles 10. There may be a plurality of radial flow paths 72 between outer radial surfaces 2, 14 of adjacent articles 10. The radial flow paths 72^: will have a flow component in the , radial direction, f_r, and. a flow component in the axial direction, f_a. According to the teachings herein the radial flow path may also have a'tangential component, f₍. There.may be a second axial flow path 74, along the outer peripheries 18 of the articles 10 (e.g., in the space between the article 10 arid the axial wall(s) 85 of the inner housing 80.

[75] FIG. 8 is a cross-sectional view showing illustrative features of components that may be employed in a HSD 60. The HSD 60 may including an outer housing 90 surrounding an inner housing 80, and a stack- of articles 10 arranged tri^' the inner housing 80 . The inner housing 80 preferably is, insulated. For example, the inner housing may be insulated by a vacuum space 96. The vacuum space 96 may be in the space between the inner housing 80 and the outer housing 90. The outer housing may have axial walls 95 that are generally cylindrically shaped. The outer housing 90 .may have opposing ends 94, which have outer surfaces that are generally convex. The inner housing may have an inlet 86 for flowing a HTF into the. cavity of the inner housing 80 and an outlet;86' for flowing a HTF out of the cavity of the inner housing 80: The device may include a delivery tube 88, for delivering a HTF from the outlet .86' of the.inner housing 80. The device' may include a receiving tube 88' so that the HTF may be received by the inlet 86 of the inner housing SO. The device 80 may include one or more seals 87 suitable for preventing the HTF from flowing directly from the inlet 86_. to the outlet 86' without first flowing through:'an axial flow path through openings of the articles, a radial flow path (e.g., between outer radial surfaces: 12, 14 of two, adjacent articles 10, or -between an outer radial surface 12, 14. of an article 1.0 and a surface 84 of the inner housing), and. a different axial flow path along outer peripheries 18 of the articles 10. One end 84 of the inner housing 80 has an outer surface that generally mates with an end of the outer housing 94. On the other end 82 of the inner housing 80 there is a large open space provided by the facing concave surfaces of the inner housing 80 and the outer housing 90, The open space preferably is sufficiently large enough for receiving: one or more windings of a.' delivery tube, one. or more windings of a receiving tube. Preferably the tubes between the housings dp not contact another tube or any surface, except in the region where the tubes connect to orifices of the inner housing and to orifices of the outer housing. Windings of a tube within a vacuum_. space may be used so that the thermal conductive losses through the tube are reduced or minimized.

[76] Instead of being filled with a stack of articles, the inner housing may be filled with a plurality of segments 50 that combined form the same general shape capable of fitting into an inner Filed Via EFS @ USPTO.gov on 04-06-2012

Attorney Docket No. 7.0928 (1062-177WO)

housing having one end that is generally concave and an opposing end that is generally convex. With reference to FIG. 13, the segments should be arranged so that they form a stack having an axial opening,, spacing is maintained between some or all-adjacent segments so that there is a radial flow path. As illustrated in FIG. 13, the stacked arrangement of segments 50 has an outer surface that is generally concave 12' and an opposing outer surface that is generally convex 14. It will be appreciated that a HTF can also flow along an axial flow path along the outer periphery edges 58.

[77] Other components of the HSQ and/or of a heat storage system may also be insulated (e.g. , using a vacuum in a gap between walls), or using a material having low thermal conductivity. For example insulation may be employed for reducing heat losses from a line for flowing a HTF.

[78] It will.be appreciated that the cavity of the housing may include sufficient space to allow for the thermal expansion of the articles, such as during a charging process where the some or all of the TESM increases in temperature and/or undergoes a solid to liquid phase transition. The HSD may optionally include a compaction component suitable for compacting a stack of articles so that the spacing between layers is generally maintained. The compaction component should be capable of applying a compressive force to the stack of articles. The compressive force preferably is sufficiently high so that rotational movement between two articles is reduced or eliminated, so that axial movement between two' articles is reduced or eliminated, orboth. The compressive force may be sufficiently low so that an article is not permanently deformed, cracked; or both. The compressive force may be sufficiently low so that the article may expand and contract due to thermal cycling, while generally maintaining a preferred spacing, between adjacent articles. By way of example, the compaction component may include one or more springs above the stack of articles, one or more springs below the stack of articles, or both. Without limitation, the compaction component may be employed to reduce or minimize the change in. the thickness of a radial flow path between two. adjacent articles when the TESM is heated, undergoes a phase transition, or both, A particularly preferred spring is a stack compression spring. A seal may be used to block the flow of the fluid at an end of an axial flow path along the openings of the stack of articles, to block the flow of a fluid at an end of an axial flow path along a periphery of the stack of articles, or both.

[79] The capsular articles, such as generally dome-shaped capsular article, containing the TESM may be formed using any method that provides for the . encapsulation of the TESM. The process of forming the article may employ one or more of the process steps for producing a capsule described in U.S. Patent Application Publication No. US 2009/0250189 A1 published on October 8, 2009 and for forming producing an article described in PCT Publication WO201 1/094371 , published on August 4, 201 1 , both incorporated herein by reference. Without limitation, the process may employ one or any combination of the following: cutting, stamping, or punching an opening (e.g. , a hole) through one or more encapsulant sheets, forming one or Filed Via EFS @ USPTO.gov on 04-06-2012

Attorney Docket No. 70928 (1062-177WO)

more encapsulant sheets to have a desired curvature, (e.g.-, a generally dome-shape), or attaching two encapsulant sheets in an orientation so that one of the sheets has a generally convex outer radial surface and the other sheet has a generally concave outer radial surface. The encapsulant sheets may be formed (e.g., thermoforming, hycVoforming, stamping, embossing, rolling, or otherwise deforming) to have a curvature.

[80] In one preferred approach, a capsular article (e.g., a dome-shaped article including one.or more capsules) is formed by encapsulating a TESM (e.g. a phase change material) between two encapsulant sheets. Preferably, the encapsulant sheets each have a center opening. The encapsulant sheets preferably are sealingly joined (e.g., to each other) around their peripher and also around the center opening.. The sheets are preferably formed before the thermal energy storage material is placed between them, but may also be formed into their final shape of the capsular article (e.g_:, having one. outer surface that is generally concave and a second opposing outer surface that is generally convex) while the TESM (e.g., in a liquid, a solid or a partially melted state) is already contained within. In a preferred process for forming a capsular article, two encapsulant sheets are partially joined (e.g., by sealing along the outer periphery and along the opening periphery) wit no TESM inside, The sheets are only partially joined and are not completely joined along the outer periphery or along the opening periphery so that a small opening (i.e., a filling port) remains, either near the. outer periphery or near the center opening. The filling port. should be sufficiently large so tnat. it may be. used for filling the capsule with the TESM. Some o^'f all of the space between the two encapsulant sheets may be filled with the TES (e.g., in a liquid state) using the filling port. After the filling step, the filling port may be closed, for example by finishing the joining of the encapsulant sheets so that a sealed space including the TESM is formed. The sheets may be sealingly ^"joined by any suitable joining method that results in a durable capsule. The joining step . may include welding (e.g.,_: laser welding, diffusion bonding, soldering, brazing, gluing, crimping (method used to seal soup cans) with or without gaskets, or any combination thereof. A particularly preferred welding method is a continuous welding process that employs a laser or other continuous heating method suitable for joining two metal sheets: along a periphery.

[81 ] The encapsulant sheet may be any suitable metal or alloy, such as those described in U.S.. Patent Application Publication No, US .2009/0250189 A1 published on October 8, 2009 and for forming producing an article described in. PCT Publication WO201 1 /094371 , published on August 4, 201 1 , both incorporated herein by reference.

[82] The HSD may be used in a heat storage system that employs one or more HTFs for transferring heat into the HSD, for transferring heat out of the HSD, or both, such as a heat storage system describe in U.S. Patent Application Publication No. US 2009/0250189 A1 published on October 8, 2009 and for forming producing an article described in PCT Publication WO201 1/094371 , published on August 4, 20 1 , both incorporated herein by reference. Filed Via EFS @ USPTO.gov on 04-06-2012

Attorney Docket No. 70928 (1062-177WO)

[83] The HSD. may be used in a process for heating one or more components. The process may include flowing a HTF through the heat transfer device. The step of flowing a HTF through the HSD may include flowing a HTF having an initial temperature through an inlet of the device; flowing the HTF through an axial flow path so the HTF can be divided into a plurality of radial flow paths; flowing the HTF through a radial flow path (e.g., having a radial component and an axial component to the flow direction, and optionally a tangential component to the: flow direction) so that it. can remove heat from the TESM, wherein the TESM has a temperature greater than the initial temperature of the HTF; flowing the HTF through a different axial flow path so that a plurality of radial flow paths can recombine; flowing the HTF having an exit temperature through an outlet of the device; or any combination. thereof. Preferably the HTF exit temperature is greater than the initial temperature of the HTF. The process for heating one^'or more components may employ a flow path through the HSQ including one of a selection of radial flow path and two axial flow, paths, the flow, path having a total flow length, wherein the total flow length is generally constant for the different radial flow paths.

[84] The HSD and/or the heat storage system may characterized as haying a relatively high power (e.g., as measured during the initial 30 or 60 seconds of heating) so that it can rapidly Heat a component; such as ah internal combustion- engine. The HSD and/or the' heat storage system may be characterized by an average power of about 5 watts or more, or about 20 watts or more. The ;HSD and/or. the heat storage system may be characterized as having a relatively high power density, so that it can hold a large quantity of thermal energy in a relatively small compartment. For example, the HSD and/or the heat storage system may be characterized as having a power density of about 4 kW/L or more, about 8 kW/L or more, or about 12 kW/L or more. The HSD and/or the heat storage system may be characterized as having a relatively low pressure drop of the HTF (measured at a HTF flow rate of about 10 L/min). For example, the; HSD ^'and/or .the heat storage system may be characterized as having a HTF pressure drop of about 2.0 kPa or less,, or about 1.0 kPa or less. The heat storage system maybe capable of operating in a charging mode, where the HSD receives heat so that the temperature of the TESM increases, so that the TESM undergoes a solid to liquid phas transition, or both.

[85] A thermal energy storage system for storing heat, such as heat from a vehicle exhaust may include some or all of the features illustrated in FIG. 14. The thermal energy storage system 100 includes the HSD 60, such as a HSD according to the teachings herein. The thermal energy storage system may include a heat exchanger or condenser 102 having a first inlet 1 17 for a first HTF 107 and a first outlet 1 17 for the first. HTF. The thermal energy storage system 100 may have a tube (e.g.,, a line) 113 connecting the first HTF inlet 111 of the heat exchanger 102 to the first HTF outlet of the HSD 101. The thermal energy storage system 100 may have a tube 109 connecting the first HTF outlet 1 17^" of the heat exchanger 102 to the first HTF inlet of the HSD 101. The first HTF 107 flows through a first HTF compartment of the HSD 101. The Filed Via EFS @ USPTO.gov on 04-06-2012

Attorney Docket No. 70928 (1062-177WO)

first HTF may flow through a first HTF compartment of the heat exchanger 102. The first HTF may be a working fluid, the line from the HSD 101 to the heat exchanger 102 may be a vapor line, the heat exchanger 102 may be a condenser for the working fluid, and the first HTF compartments may be working fluid compartments. As such, the thermal energy storage system 100. may contain a capillary pumped loop including the working fluid compartment in the HSD, a working fluid compartment in the condenser, the working fluid vapor tube 109, and the working fluid liquid tube 1 13. The thermal energy storage system also includes one or more HTF or working fluid reservoirs 1 10. When used in a capillary pumped loop, the reservoir 1 10 preferably has a fill level that is higher in elevation than the working fluid inlet of the HSD 101 and lower than the. elevation of the working fluid outlet 117 of the condenser, the working fluid inlet 1 1 1 of the condenser, or both. The thermal energy storage system 100 may include a valve 1 18 to regulate the flow of the first HTF in the tube 1 13 connecting the HSD 101 and the heat exchanger 102. For example, the valve 118 may. be used to prevent the HTF from circulating when the HSD is charging and when the HSD is storing heat. The valve 1 18 may be opened when it is desired to discharge heat from the HSD. Referring again to FIG. 10, the thermal energy storage system may includes a HTF inlet line ί 08 and a HTF outlet line 106, for flowing a second HTF into and out of the HSD 101. The thermal energy storage system may also have a HTF bypass-line 105 and a diverter . valve (e.g., a bypass valve) 104 to divert some or all of the second HTF to the bypass line 105 (e.g., when the HSD is fully charged, or when the temperature of the second HTF is below a terhperature of the TESM in the HSD 101 ). The thermal energy storage system may also include a cold line 116 for providing another HTF into the heat. exchanger, and a. heat line 115 for removing the heated HTF from the heat exchanger 102. The cold line 1 16 and heat line 1 15 are part of a HTF loop 1 14. The HTF loop 1 14 may contains an engine .coolant. The HTF loop 1.1.4 may be connected to an internal combustion engine 103. As such, the thermal energy storage system 100, may heat an internal combustion engine 103 with the energy stored in the HSD. 101.

[86] Furthermore, the present .invention may be used in combination with additional elements/components/steps such as those described in in U.S. Patent Application Publication. No. US 2009/0250189 A1 published on October 8, 2009 and for .forming producing an article described jn PCT.Publication WO201 1/094371 , published on. August 4, 201 1 , both incorporated herein by reference.

[87] While the present invention may be .susceptible to various modifications and alternative forms, the exemplary embodiments discussed above have been shown by way of example. However, it should again be understood that the invention is not intended to be limited to the particular embodiments disclosed herein. Indeed, the present techniques of the invention are to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the following appended claims.

Claims

Filed Via EFS @ USPTO.gov on 04-06-2012 Attorney Docket No. 70928.(10627177W0) CLAIMS What is claimed is

1 . An article comprising

one or more thermal energy storage materials;

one or more sealed spaces encapsulating the thermal energy storage materials;

the article including a first outer radial surface having a generally concave shape and a^: second opposing outer radial surface having a generally convex shape,

one or more^'fluid passages which are sufficiently large to ajlow a heat transfer fluid to flow through the one or more fluid passages,

wherein the thermal energy storage material is isolated from the heat transfer fluid,

2. The article of claim 1 , wherein one . or more of the sealed spaces includes a conductive component to increase heat transfer rate between: the thermal energy storage material and the outside surfaces of the capsular article.

3. The article claim 1 or 2, wherein the thermal energy storage material is a phase change material having a solid to liquid transition temperature greater than about 30 °C and less than about .350 °C.

4. The article of any of claims 1 through 3; wherein the article includes:

i) a first sheet having an opening and an outer periphery, and

iij a second sheet having an opening that corresponds to the opening of the first sheet. and an outer periphery that 'corresponds' to the outer periphery of the first sheet; wherein the first sheet and the second sheet are sealingly attached along the.entirety of their corresponding openings and outer peripheries, so that the thermal energy storage material is contained in the^' sealed space between the'two sheets; and

wherein the outer surface of the first sheet and the.second sheet are the opposing concave and convex outer radial surfaces of the article.

5. The article of any of claims 1 through 4, wherein the article, has ah opening region near the opening of the article, an outer periphery region near the outer periphery of the article and a mid region between the opening region and the outer periphery region,_, wherein

the .thickness of the article decreases going from the opening region to the outer periphery region.

6. The article of any of claims Ί through 5, wherein the ratio of the surface.area of the generally convex outer radial surface to the area of its axial projection is about 1.02 or more, so that the article may be used in a heat storage device having a generally high power capacity.

7. The article of any of claims Ί through 6, wherein the article has a generally dome shape so that a stack of the articles can generally fill the cavity of a housing that is generally cylindrical with generally semiejlipsoidal ends, wherein one .end is concave and the other is convex. Filed Via EFS @ USPTO.gov on 04-06-2012

Attorney Docket No. 70928 (1062-177WO)

8. The article of any of claims 1 through 7, wherein the opposing outer radial surfaces each have a plurality of spiral ridges and valley, wherein the spiral of one surface is clockwise and the spiral of the other surface is counterclockwise as viewed from above the article looking at the first outer surface, so that mixing is promoted when a heat transfer fluid flows between a pair of the articles.

9. An article comprising:

a -first metal sheet;

a second metal sheet, wherein the metal sheets are sealingly joined to form_, one or more sealed spaces, wherein the sheets have opposing outer radial surfaces including one that is generally concave and the other that is generally convex;

a thermal energy storage material contained within the sealed spaces;

wherein the sealed spaces includes water at a concentration of about 1 percent by volume or less at a temperature of about 25 °C,,

10. A device including a sta^'ck of the articles of any of claims 1 to 9.

1 1. The device of claim 10, wherein the device comprises:

i) an outer housing,

ii) an inner housing having one end that is generally concave, the inner housing supported inside the outer housing,

iii) an evacuated space between the two housings,

wherein the stack of articles is arranged inside the inner housing, and a tube for carry a heat transfer fluid extends between the inner housing and the. outer housing for carrying a heat transfer fluid to the inner housing, wherein the tube includes at least one winding of the tube in the concave end of the inner housing, so that while operating the device in a heat storing mode, thermal losses due to the tube are reduced.

12. The device of claim.11 ,· wherein the tube has a plurality of windings so that the heat flow path is increased.

13. The device of any of claims 10 through 12,. wherein the device includes an inner housing having one end that is generally concave and an opposing, end that is generally convex for receivings stack of articles that are generally dome-shaped.

14.. The device of any of claims 10 through 13, wherein the device includes a static.mixing element between two adjacent articles.

15. The use of the device of any of claims 10 through 14 for storing heat in a vehicle.

16. A heat storage system comprising:

i) the heat storage device of any of claims 10; through 14;

ii) a component to be heated; Filed Via EFS @ USPTO.gov on 04-06-2012

Attorney Docket No. 70928 (1062-177WO)

iii) a thermal connection between the heat storage device and the component to be heated; wherein the thermal connection is capable of removing heat from the heat storage device by circulating a heat transfer fluid;

iv) a heat transfer fluid; and

v) a circulating device for controlling the flow of the heat transfer fluid between the heat storage device arid the component to be heated.

17. A method for removing heat from a heat storage device comprising the steps of:

i) flowing a heat transfer fluid having an initial temperature into a heat storage device;

ii) flowing the heat transfer fluid through a first axial flow path;

iii) dividing the flow of the heat transfer fluid between a plurality of radial flow paths that each includes a radial component and an :axial component;'

iv) flowing the heat transfer fluid through the radial flow paths, wherein a radial flow path is defined by the space between a generally convex outer radial surface of an article that contains a thermal energy storage material and a generally concave,outer radial surface of an adjacent article, wherein the thermal energy storage material has a temperature greater than the initial temperature of the heat transfer fluid,. so that the heat transfer fluid can remove heat from the thermal energy storage material;

y) flowing the heat transfer fluid through a different axial flow path where the plurality of radial flows recornbirie;

vi) flowing the heat transfer fluid having. an exit temperature out of the device; wherein the exit temperature is greater than the initial temperature of the heat transfer fluid.

18. The method of claim 17, wherein the step of flowing the heat transfer fluid through a radial flow path includes flowing the heat transfer fluid through a static mixer, so that the. heat transfer fluid^' more efficiently removes heat from the thermal energy storage material.

19. A method for preparing an article,. comprising a step of: sealingly attaching two sheets each having a surface with a curvature and having corresponding openings, so that an outer surface: of the one sheet is generally convex and an opposing outer surface of the other sheet is generally concave.

20. The method of claim 18 or 19, wherein the process comprises the steps of: i) partially sealingly attaching the first sheet and the second sheet along their opening and outer peripheries, wherein one or more filling ports is created, wherein the filling port is suitable for flowing a molten thermal energy storage material into the space between the two sheets;

ii) at least partially filling the space between the two sheets with a thermal energy storage material;

iii) closing the filling port by further sealingly attaching the two sheets, so that the thermal energy storage material is encapsulated within the article.