MX2013001797A - Articles and devices for thermal energy storage and methods thereof. - Google Patents

Abstract

The present invention relates to articles 2 and heat storage devices 80 for storage of thermal energy. The articles 2 include a metal base sheet 12 and a metal cover sheet 14, wherein the metal base sheet and the metal cover sheet are sealingly joined to form one or more sealed spaces 18, The articles 2 include a thermal energy storage material 16 that is contained within the sealed spaces 18. The sealed spaces preferably are substantially free of wafer or includes liquid water at a concentration of about 1 percent by volume or less at a temperature of about 25 °C, based on the total volume of the sealed spaces 18. The articles include one or more of the following features: a) the pressure 36 in a sealed space is about 700 Torr or less, when the temperature of the thermal energy storage material is about 25 °C; b) the metal cover- sheet 14 includes one or more stiffening features 34, wherein the stiffening features Include indents into the sealed space, protrusions out of the sealed space, or both, that are sufficient in size and number to reduce the maximum von Mises stress in the cover sheet during thermal cycling; c) the metal cover sheet 14 and/or the metal base sheet 12 includes one or more volume expansion features 62; or d) the metal cover sheet has a thickness, tc, and the metal base sheet has a thickness, tb, wherein tc is greater than tb; so that the article is durable. For example, the article does not leak after thermal cycling between about 25 °C and about 240 °C, for 1,000 cycles.

Description

ARTICLES AND DEVICES FOR STORAGE OF THERMAL ENERGY AND METHODS OF THE SAME " Field of the Invention The present invention relates to thermal energy storage using a thermal energy storage material from and in the packaging of thermal energy storage material to allow both efficient heat storage and efficient thermal transfer.

Claims for benefit of filing date The present invention claims the benefit of the filing date of the provisional patent application of E.U.A. 61 / 373,008 (filed August 12, 2010) and the patent application of E.U.A. 13 / 207,607 (filed on August 11, 2011), the contents of which are hereby incorporated by reference in their entirety.

Background of the Invention In general, the industry has been actively seeking a new approach to efficiently capture and store waste heat so that it can be used at a more timely time. In addition, the desire to achieve energy storage in a small space requires the development of new materials that are capable of storing a high energy content per unit weight and unit volume. The areas of potential application of cutting-edge technology include transportation, solar energy, industrial manufacturing processes, as well as heating of municipal and / or commercial buildings.

As for the transport industry, it is known that internal combustion engines operate inefficiently. The causes of this inefficiency include the heat that is lost through discharges, cooling, radiant heat and mechanical losses of the system. It is estimated that more than 30% of the energy of the fuel supplied to an internal combustion engine (internal combustion engine) is lost in the environment through the engine exhaust.

It is known that during a "cold start" the internal combustion engines operate with a considerably lower efficiency, generate more emissions, or both, because the combustion takes place at a non optimal temperature and the internal combustion engine needs to perform additional work against friction due to the high viscosity of the cold lubricant. This problem is even more important for hybrid electric vehicles in which the internal combustion engine operates intermittently thus prolonging cold start conditions, and / or generating a plurality of incidents of cold start conditions during a single period of operation vehicle. To help solve this problem, OEMs are looking for a solution capable of achieving efficient waste heat storage and release. The basic idea is to recover and store the residual heat during normal operation of the vehicle, followed by a controlled release of this heat subsequently, reducing or thus minimizing the duration and frequency of the cold start condition and ultimately improving the efficiency of the internal combustion engine, reducing emissions, or both.

To be a practical solution, the energy density and energy density requirements for a thermal energy storage system are extremely high. Applicants have previously submitted 1) the publication of the patent application of E. U.A. no. 2009-021 1 726 by Soukhojak et al, entitled "Thermal Energy Storage Materials" and published on August 27, 2009; 2) the publication of the patent application of E. U.A. no. 2009-02501 89 by Bank et al. , entitled "Heat Storage Devices" and published on October 8, 2009, 3) PCT application no. PCT / US09 / 67823, entitled "Heat transfer systems using thermal energy storage materials" ("Heat Transfer Systems Utilizing Thermal Energy Storage Materials") and submitted on December 14, 2009, and 4) provisional application of U .A. no. 61/299, 565 entitled "Thermal Energy Storage" and filed January 29, 201 0. These prior applications are hereby incorporated by reference in their entirety.

Known heat storage devices and exhaust heat recovery devices are known from the prior art. However, in order to provide a long-term heat storage capacity (eg higher than about 6 hours), generally occupy a large volume, require a large volume of heat transfer fluid, require a relatively large pump to overcome hydraulic resistance, and the like. Therefore, there is a need for a heat storage system, which can offer an unprecedented combination of high energy density, high power density, long heat retention time, light weight, low hydraulic resistance for the flow of heat. heat transfer fluid, or any combination thereof.

The issue of packing thermal energy storage materials for applications that require systems that are lightweight, such as in transportation, requires both heavy duty and lightweight packaging. For example, the packaging must be durable, so that it can contain a large concentration of thermal energy storage material, contain the thermal energy storage material over a wide range of temperatures (over which large temperatures can be experienced). changes in volume), contain the thermal energy storage material in a plurality of cells or capsules that are sealed together, or any combination thereof. The need for light energy storage systems may require reducing the weight of the package.

For example, there is a need for thermal energy storage material that is encapsulated in lightweight capsules, has a high energy density, or has a high power density, and is durable (for example, so that the capsules do not leak after heating to a temperature of about 400 ° C, the capsules do not leak after heating several times between a temperature of about 25 ° C and a temperature of about 240 ° C for about 1,000 cycles or more , or both).

Brief Description of the Invention One aspect of the invention is an article comprising: a base sheet (preferably, a metal base sheet); a cover sheet (preferably, a metal cover sheet) hermetically attached to the base sheet to form a capsular structure, wherein the capsular structure includes one, two or more sealed spaces; a thermal energy storage material, in which the thermal energy storage material is contained within the sealed spaces, and in which the thermal energy storage material has a melting temperature of about 150 ° C or more; where the sealed spaces practically lack water or includes liquid water at a concentration of approximately 1% by volume or less at a temperature of approximately 25 ° C, based on the total volume of the sealed spaces; and wherein the article includes one or more of the following characteristics: a) the pressure in a sealed space is a vacuum of approximately 700 Torr or less, when the temperature of the thermal energy storage material is approximately 25 ° C; b) the cover sheet includes one or more reinforcement elements, wherein the reinforcement elements include notches within the sealed space, projections outside the sealed space, or both, which are sufficient in size and number to reduce the maximum stress von Mises on the cover sheet during thermal cycling; c) the base sheet and / or the cover sheet include one or more volume expansion elements; or d) the cover sheet has a thickness, tc, and the base sheet has a thickness, t, where tc is greater than tb; such that the article does not leak after thermal cycling between about 25 ° C and about 240 ° C, during approximately 1, 000 cycles. The reinforcement element can be any element (such as a notch or a protrusion) that redistributes the stresses in the base sheet and the cover sheet so that when the pressure in the sealed space is increased (for example, due to the thermal expansion, or melting the thermal energy storage material) reduces the maximum von Mises stress as compared to a base sheet and / or a cover sheet without the reinforcing element and subjected to the same pressure. Without limitation, examples of reinforcement elements that may be employed in the metal cover sheet include depressions, chevrons, rods or any combination thereof.

In a particularly preferred aspect of the invention, the capsular structure has one or more fluid passages which are large enough to allow a heat transfer fluid to flow through said one or more fluid passages; and when the capsular structure is in contact with a heat transfer fluid, the thermal energy storage material is isolated from the heat transfer fluid.

Another aspect of the invention is a device that includes a container and a stack of two or more articles within the container. For example, the device may contain a plurality of articles described herein. Preferably, each article includes a fluid conduit and contains the thermal energy storage material. Preferably, articles having a fluid conduit are stacked so that their fluid conduits are generally aligned, preferably axially.

Another aspect of the invention is a process for preparing an article, such as an article described herein, which includes the steps for: forming one, two or more hoppers with a thermal energy storage material; ii) at least partially fill one, two or more hoppers with a thermal energy storage material; and at least partially joining (eg, sealing) a first metal sheet (eg, the base sheet) with a second sheet metal (eg, cover sheet) to form a sealed space; wherein the thermal energy storage material includes a metal salt, and wherein the metal salt is in the molten state during the bonding step.

Yet another aspect of the invention relates to a process for storing heat comprising a step for: transferring a sufficient amount of thermal energy to an article of the invention, such that the thermal energy storage material in the article is heated at a temperature of about 200 ° C or more.

The articles, devices, systems and processes of the present invention are advantageously capable of containing a high concentration of thermal energy storage material in such a way that a large amount of thermal energy can be stored (for example, having a high energy density). ), are capable of having a large surface area between the heat transfer fluid and the article containing the thermal energy storage material such that the heat can be rapidly transferred to and / or out of the energy storage material thermal (for example, having a high power density, preferably greater than about 8 kW / L), are capable of having multiple flow paths having a similar or equal hydraulic resistance so that the heat is uniformly transferred to and / or transfer from different regions; they have a rotational symmetry so that they can be easily placed; They have a structure that is strong and durable; have a high density of heat storage so that they can be used in applications that require compact designs, lightweight components, or both; have lower hydraulic resistance for a heat transfer fluid flow (e.g., a pressure drop of less than about 1.5 kPa at a heat transfer fluid pumping rate of about 10 liters / min) in such a way that the pumping requirements for the heat transfer fluid are reduced, are sufficiently strong so that the thermal energy storage material does not leak from a sealed space after heating a capsular structure that it includes the thermal energy storage material at a temperature of approximately 400 ° C, they are sufficiently durable so that the thermal energy storage material does not leak from a sealed space after heating the capsular structure several times with the material of thermal energy storage between about 25 ° C and about 240 ° C for about 1, 000 cycles or more, or a combination thereof.

Brief Description of the F igures The present invention is further described in the detailed description which is disclosed below, with reference to the plurality of drawings seen by way of non-limiting examples of embodiments of the present invention, in which the reference numbers represent similar parts in the various views of the drawings, and in which: Figure 1 is a drawing of an illustrative article having a sealed compartment.

Figure 2A is a cross-sectional view of an illustrative article including a plurality of sealed spaces.

Figure 2B is a cross-sectional drawing illustrative of an individual capsule having a sealed space that can be employed in the article.

Figure 3 is a drawing of an illustrative base sheet that can be employed in the article.

Figure 4A is a drawing of an illustrative cover sheet having chevrons that can be employed in the article.

Figure 4B is a drawing of an illustrative capsule including a cover sheet having depressions that can be employed in an article having one or more capsules.

Figure 4C is a drawing of a section of an illustrative cover sheet including depressions that may be employed in the article.

Figure 4D is a drawing of an illustrative cover sheet having a plurality of reinforcing elements, such as the plurality of projections and / or grooves that can be used in an article.

Figure 5A is a cross-sectional drawing illustrative of a sealed compartment at the temperature at which the compartment is sealed.

Figure 5B is a cross-sectional drawing illustrative of a sealed compartment at a temperature lower than the sealing temperature.

Figure 5C is a cross-sectional drawing illustrative of a sealed compartment at a temperature above the sealing temperature.

Figures 6A, 6B and 6C are drawings of an illustrative sheet that has been formed to have rods.

Figures 7A and 7B are drawings illustrating a sheet having a volume expansion element that allows to increase the volume of the sealed space (for example, to accommodate the volume expansion of the thermal energy material as it is heated and / or melt).

Figure 8 is an illustrative graph showing the relationship between the thickness of the cover sheet and the maximum von Mises stress in the cover sheet when the cover sheet is used in an article containing a storage material of thermal energy and the thermal energy storage material is heated.

Figure 9 is an illustrative graph showing the relationship between the thickness of the cover sheet and the maximum expected stress of von Mises on the cover sheet for a cover sheet that is flat and for a cover sheet including rods .

Figure 10 is an illustrative graph showing the relationship between the thickness of the cover sheet and the maximum expected von Mises tension in the cover sheet for a cover sheet that is flat, for a cover sheet including depressions , for a cover sheet that includes chevrons, and for a cover sheet that includes rods.

Figure 11 is a drawing illustrating a portion of the tooling that can be used in the manufacture of a sheet including rods.

Figure 1 2 shows an illustrative stack of articles.

Figure 13 shows a surface of a base sheet of an article that includes one or more sealed compartments. Figure 13 illustrates that a sealed compartment may have a main seal and one or more secondary stamps.

Figure 14 is a drawing of an illustrative heat storage device.

Figure 1 5 is a drawing of an illustrative tooling for stamping a base sheet.

Figure 16 shows a surface of a base sheet of an article that includes one or more spaces that are filled with thermal energy storage material using a nozzle.

Detailed description of the invention In the following detailed description the specific embodiments of the present invention are described in relation to their preferred embodiments. However, insofar as the following description is specific to a particular embodiment or to a particular use of the present techniques, it is intended that they are only illustrative and simply provide a concise description of the modalities by way of example. According to the foregoing, the invention is not limited to the specific embodiments described below, but rather, the invention includes all alternatives, modifications and equivalents that fall within the true scope of the appended claims.

As will be appreciated from the present teachings, the present invention provides unique articles, devices, systems, and processes for storing thermal energy and / or transferring stored thermal energy to a fluid. For example, articles and devices for storing thermal energy of the present invention are more efficient in the storage of thermal energy, allow the transfer of thermal energy more uniformly, allow the transfer of thermal energy with a more attenuated pressure drop of the fluid of heat transfer, or any combination thereof.

The various aspects of the invention are based on an article that includes a capsular structure having one or more sealed spaces (i.e., capsules) and one or more thermal energy storage materials that are encapsulated in said one or more sealed spaces of the capsular structure so that the thermal energy storage material can not flow out of the capsular structure, or be extracted from the capsular structure. When the thermal energy storage material is heated during operation, the volume may increase due to thermal expansion, due to the difference in the densities of the liquid and solid phases of the thermal energy storage material, or both. The increase in the volume of thermal energy storage material can be about 5% or more, about 10% or more, about 15% or more, or even about 20% or more. For example, a metal salt, such as lithium nitrate, can be increased in volume by more than 20% when heated from about 23 ° C to about 300 ° C. It will be noted that as the thermal energy storage material is heated, the pressure in the sealed space can be increased. The capsular structure must be durable enough to not leak, or fail when the thermal energy storage material expands during use. Preferably, the capsular structure has a geometry that allows a heat transfer fluid to effectively remove heat from the thermal energy storage material. Without limitation, examples of the preferred capsular structures include those described in the publication of the patent application of E.U.A. no. 2009/02501 89 by Soukhojak et al. , published on October 8, 2009, and the provisional patent application of E. U.A. no. 61 / 299,565 filed January 29, 201 0, which is incorporated herein by reference. For example, the capsular structure may have a geometry that includes one or more fluid conduits that are large enough so that the capsular structure is capable of allowing it to flow to a fluid (eg, a heat transfer fluid) through the conduit of fluid. The thermal energy storage materials can be sufficiently encapsulated in one or more of the sealed spaces so that when the heat transfer fluid contacts the capsular structure, the thermal energy storage material is isolated from the fluid.

A variety of approaches have been identified that advantageously they improve the durability of the capsular structure including having a pressure in a sealed space that is a vacuum of about 700 Torr or less when the temperature of the thermal energy storage material is about 25 ° C, using a metal base sheet which includes one or more reinforcing elements (e.g., one or more rods), using a metal cover sheet that includes one or more reinforcement elements (e.g., one or more rods, one or more depressions, one or more chevrons , or any combination thereof), using a cover sheet having a thickness greater than the thickness of the base sheet, or any combination thereof.

By reducing the pressure of a sealed space to a temperature of about 25 ° C, the pressure of the sealed space can also be reduced when heating the thermal energy storage material. The pressure of a sealed space at a temperature of about 25 ° C can be reduced to about 700 Torr or less using any convenient means. By way of example, the cover sheet and the base sheet can be joined to form the sealed space when the thermal energy storage material is at a junction temperature,? , which is high enough that when the thermal energy storage material is cooled in the sealed space, the thermal energy storage material contracts and the pressure in the sealed space drops below approximately 700 Torr. The binding temperature may be higher than the melting temperature, TL.TESM, of the thermal energy storage material. Preferably the binding temperature, Tj, is about TL.TESM + 10 ° C or more, even more preferably about TL.TESM + 20 ° C or more, even more preferably about TL.TESM + 30 ° C or more, even more preferably from about TL.TESM + 40 ° C or more, even more preferably from about TL.TESM + 50 ° C or more, and most preferably from about TL.TESM + 60 ° C or more. By way of example, Tj can be about 200 ° C or more, preferably about 230 ° C or more, more preferably about 250 ° C or more, even more preferably about 270 ° C or more, and very preferably about 290 ° C or more. The temperature of the thermal energy storage material when joining the base sheet and the cover sheet can be about 700 ° C or less, preferably about 500 ° C or less, and more preferably about 400 ° C or more. less.

In another example, the cover sheet and the base sheet can be joined while applying a vacuum to the region that becomes the sealed space. If used, the vacuum must have a sufficiently low pressure so that, by tightly joining the base sheet and the cover sheet, the sealed space is a vacuum. For example, a vacuum may be applied at a pressure of about 700 Torr or less, approximately 660 Torr or less, approximately 550 Torr or less, approximately 500 Torr or less, approximately 400 Torr or less, or approximately 300 Torr or less. As such, the entire bonding process can be performed in a vacuum environment. The cover sheet and the base sheet can be joined while the pressure in the region that becomes the sealed space is about 0.1 Torr or more, preferably about 1.0 Torr or more, and more preferably about 10 Torr or more. Lower pressures may also be employed. Preferably, the thermal energy storage material is at a predetermined sealing temperature, which is a high temperature when the base sheet and the cover sheet are hermetically joined, so that upon cooling the article to about 25 ° C it is forms a vacuum in the sealed space. The predetermined sealing temperature can be any temperature at which the density of the thermal energy storage material is less than its density at 25 ° C. Preferably, the predetermined sealing temperature is greater than the melting temperature of the thermal energy storage material (eg, greater than the melting temperature by about 10 ° C or more, by about 30 ° C or more, or by about 60 ° C or more). The predetermined sealing temperature may be about 50 ° C or more, about 100 ° C or more, about 150 ° C or more, about 200 ° C or more, about 250 ° C or more, or about 300 ° C or more . Preferably, the predetermined sealing temperature is sufficiently low so that the thermal energy storage material is not degraded during the sealing process. The predetermined sealing temperature can be about 500 ° C or less, about 400 ° C or less, or about 350 ° C or less.

When the thermal energy storage material in the sealed space is at a temperature of about 25 ° C, the sealed space is preferably a vacuum of about 600 Torr or less, more preferably about 500 Torr or less, still more preferably about 400 Torr or less and most preferably about 300 Torr or less. The lower limit on the pressure in the sealed space when the thermal energy storage material is at 25 ° C is based on the production feasibility and is preferably about 0.1 Torr or more, more preferably about 1 Torr and most preferably of about 10 Torr or more.

The durability of the capsular structure can be increased by the addition of one or more reinforcing elements to the base sheet, the cover sheet, or both. The reinforcement element can be any feature that redistributes the stresses in the base sheet and the cover sheet so that when the pressure in the sealed space is increased (e.g., due to thermal expansion, or melting the storage material) of thermal energy) the maximum von Mises stress is reduced compared to a base sheet and / or the cover sheet without the reinforcement element and subjected to the same pressure. The reinforcing elements may be a notch or protrusion formed in a sheet. As such, the reinforcement element may be a change in the profile of the sheet. The reinforcement element can work by redistributing the stresses in a sealed space (for example, the stresses obtained when the sealed space is heated), so that the maximum von Mises stress is reduced. A reinforcement characteristic can be described by its depth (i.e., the amount of change in the profile, as compared to the region removed from the reinforcement characteristic), its length, its width, or any combination thereof. The reinforcing element preferably has a depth of about 0.1 mm or more, more preferably about 0.2 mm or more, even more preferably about 0.3 mm or more, even more preferably about 0.4 mm or more, even more preferably about 0.5. mm or more, and most preferably of about 0.6 mm or more. The reinforcing element preferably has a sufficiently small depth so that the effect of packing or stacking multiple capsular structures, as described herein, is not affected. As such, the reinforcing element preferably has a depth of about 10 mm or less, more preferably about 5 mm or less, still more preferably about 3 mm or less and most preferably about 2 mm or less. Without limitation, examples of reinforcement elements that may be employed include rods, depressions, chevrons, and the like. The reinforcing elements may include a projection or notch having a length-to-width ratio that is greater than about 1, preferably about 2 or more, even more preferably about 4 or more and preferably about 10 or more, such like a rod. If used, two rods in a base sheet or cover sheet in the region of a sealed space may be parallel, perpendicular or at an acute angle. The reinforcing element may have a generally circular cross section, such as a depression. The reinforcement elements may be placed in a repeating pattern that includes a plurality of reinforcement elements aligned in one direction and a plurality of reinforcement elements aligned in a different direction, such as a chevron pattern. The reinforcing elements are preferably placed in the regions of the sheet containing a sealed space. There may also be elements of stiffness located in the region of a sheet that does not contain a sealed space.

The reinforcement elements (for example, the reinforcing elements in a cover sheet) can have a size and number sufficient for the maximum von Mises stress of the capsular structure that houses the thermal energy storage material and heated to 250 ° C is less than the von Mises stress of an identical capsular structure, except that the reinforcing element is removed (for example, a sheet having a generally smooth surface, generally flat, or both, such as a cover sheet generally flat and soft). The reinforcing elements are preferably present in a sufficient size and number of So that the von Mises stress in the capsular structure that houses the thermal energy storage material at 250 ° C is reduced by about 5% or more, more preferably by about 10% or more, even more preferably by about 15% or more. more, still more preferably at about 20% or more, still more preferably at about 30% or more and most preferably at about 40% or more, compared to the von Mises tension of an identical capsular structure, except that the The reinforcing element is removed (for example, the sheet has a generally smooth, generally flat surface, or both).

The reinforcement element (optionally together with one or more other elements described herein) can be used to reduce the maximum von Mises stress in a sealed space containing the thermal energy storage material so that at a temperature of 250 ° C, the ratio of the maximum von Mises stress in the base sheet and the cover sheet, SMa, 2so > to the yield stress of the metal at 250 ° C (for example, the metal of the cover sheet, or the bottom of the base sheet and the cover sheet), SY, 25O, is preferably about 0.95 or less, more preferably of about 0.90 or less, still more preferably of about 0.85 or less, still more preferably of about 0.80 or less, and most preferably of about 0.70 or less.

The durability of the capsular structure can be increased by adding one or more rods to the base sheet, the cover sheet or both. Preferably, the base sheet, the cover sheet includes a rod structure (eg, a sufficient number or rods and / or rods of sufficient size) that provides sufficient rigidity to the capsular structure so that the capsular structure does not bend sufficiently to the limit and, otherwise, do not distort enough to the limit.

It will be observed in accordance with the teachings herein that the base sheet may have a structure, such as a structure that includes one or more hoppers, which is generally stiffer than the cover sheet. Advantageously, the thickness of the base sheet can be reduced sufficiently, so that the stiffness of the base sheet corresponds to the rigidity of the cover sheet. By reducing the thickness of the base sheet, the volume of the base sheet and / or the packing material can be reduced, the weight of the base sheet and / or the packing material, or both, can be reduced. Consequently, a greater percentage of the weight of the capsular structure may be the weight of the thermal energy storage material. As such, the base sheet may have a thickness (e.g., an average thickness) of t, and the cover sheet may have a thickness (e.g., an average thickness) of about tc, where tc is greater than tb. The tc / tb ratio is preferably about 1.05 or more, more preferably about 0.110 or more, even more preferably about 1. 1 5 or more, even more preferably from about 1 .20 or more, even more preferably from about 1.25 or more, still more preferably about 1.30 or more and most preferably about 1.35 or more. The difference between tc and tb is preferably about 0.01 mm or more, more preferably about 0.02 mm or more, even more preferably about 0.03 mm or more, even more preferably about 0.035 mm or more, even more preferably about 0.04 mm or more and most preferably about 0.05 mm or more. The difference between tc and tb is preferably about 1 mm or less, more preferably about 0.5 mm or less, and most preferably about 0.25 mm or less. By way of example, i) the ratio of tc / tb can be about 1.05 or more, about 1.10 or more, about 1.20 or more, or about 1.30 or more; ii) the difference between tc / tb may be about 0.01 mm or more, about 0.02 mm or more, about 0.03 mm or more, or about 0.05 mm or more; or both (i) and (ii).

The base sheet, the cover sheet or both may have one or more volume expansion elements so that the volume of the sealed space can be reversibly increased as the thermal energy storage material expands during heating and / or fusion. Examples of volume expansion elements include wrinkles, creases, convolutions, bends, oscillations, and the like. As an example, the element of Volume expansion can include one, two, or more convolutions, folds or folds. Preferably, the volume expansion element may generally have a bellows, in the form of an accordion (although, typically without a hole). A reinforcing element, such as one or more depressions, one or more chevrons, or one or more rods, may also function as a volume expansion element. It will be noted that the size, the shape of a volume expansion element and the number of volume expansion elements will affect the amount by which the volume of the sealed space is capable of expanding. If employed, the volume expansion elements may be sufficient to increase the volume of the sealed space by approximately 5% or more, preferably by approximately 10% or more, more preferably by approximately 13% or more, and most preferably by approximately 15%. % or more. The volume expansion element may allow the sealed space to expand sufficiently for the internal pressure in the sealed space to change and increase by approximately 35 kPa or less (preferably by approximately 20 kPa or less, and more preferably by approximately 10 kPa or less ) when the thermal energy storage material is heated from about 25 ° C to a temperature at which the thermal energy storage material is a liquid (e.g., about 200 ° C, about 240 ° C, or about at 250 ° C).

Other aspects of the invention include configurations novelties that include a plurality of articles, novel devices that include one or more of the articles, novel processes for the manufacture of the article, and novel processes to use one or more articles. By using the novel article, it is possible to assemble devices capable of storing a large amount of thermal energy, capable of rapidly transferring thermal energy inside or outside the thermal energy storage material, capable of being compact, capable of being lightweight, capable of of having a low pressure drop of a heat transfer fluid, or any combination thereof.

The capsular structure generally has a dimension in one direction (ie, a thickness) that is smaller than the dimensions in the other directions. Without limitation, examples of capsular structures include those described in the patent application of E.U.A. no. 1 2 / 389,598 entitled "Heat Storage Devices" and filed on February 20, 2009 and the provisional application of E. U.A. no. 61/299, 565 entitled "Thermal Energy Storage" and filed January 29, 2010, both incorporated herein by reference.

The shape of the structure and / or capsular article can be defined by the packing space and can assume an irregular shape. The article may include a cover sheet (i.e., a cover sheet) having a top surface and a generally opposite base sheet having a bottom surface. The cover sheet (e.g., the top surface of the cover sheet), the base sheet (e.g., the bottom surface of the base sheet), or both, may have a portion that is (or may be) generally flat (for example, they have a generally flat surface), generally arched, or any combination thereof. Preferably, the base sheet and / or the bottom surface of the base sheet includes a generally arched portion or is generally arched, the upper surface of the article is generally flat (e.g., the cover sheet is generally flat), or both. In various embodiments of the invention, a generally planar cover sheet may include one or more reinforcement elements (such as one or more rods, depressions, chevrons, or other protrusions or grooves as described herein) and / or one or more volume expansion elements. As described herein, a cover sheet can also be replaced by a second base sheet. As such, the capsular structure can be defined by two base sheets that are the same or different.

The capsular structure may include one or more openings, such as a fluid conduit. For example, the capsular structure can include one or more fluid conduits such that a fluid, such as a heat transfer fluid, can flow through the article without contacting the thermal energy storage material. Without limitation, the capsular structure may include a fluid conduit having one or more of the elements described in paragraphs 7-1 2, 28-43, and 54-67, and Figures 1, 2, 3, 4, 5 , 6, and 7 of the US provisional application no. 61 / 299,565 entitled "Thermal Energy Storage" and filed January 29, 201 0, incorporated herein by reference.

The cover sheet and the base sheet may include one or more openings. The cover sheet and the base sheet can be positioned so that at least one opening of the cover overlaps at least one opening of the base sheet. As such, the cover sheet and the base sheet may have one or more corresponding openings. The cover sheet has an outer periphery in the regions furthest from the center of the cover sheet. The cover sheet may have one or more opening peripheries in the region of the cover sheet near an opening (preferably near the center) of the cover sheet. The base sheet has an outer periphery in a region remote from the center of the base sheet and may also have an opening periphery near the opening (preferably near the center) of the base sheet. Both the cover sheet and the base sheet may be hermetically joined to one another or to one or more other optional substructures (such as an outer ring) along the respective outer peripheries of the sheets, to form one or more sealed spaces between them. Both the cover sheet and the base sheet can be hermetically joined together, or to one or more other optional substructures (such as an inner ring) along the respective opening peripheries of the sheets, to form one or more spaces sealed between them. Preferably, the cover sheet and the base sheet are hermetically joined to one another along their respective outer peripheries, along at least one of their respective corresponding aperture peripheries, or both. Most preferably, the cover sheet and the base sheet are hermetically joined to one another both along their respective outer peripheries and along at least one of their respective corresponding aperture peripheries. It will be noted that the cover sheet and the base sheet may also be hermetically joined to one another or to one or more other optional substructures along one or more additional regions (other than their peripheries) so as to form a plurality of sealed spaces.

The capsular structure may optionally include one or more substructures that when it is hermetically joined to a base sheet and a cover sheet forms one or more sealed spaces. Without limitation, the substructure, if employed, may include one or any combination of the elements described in the provisional application of E. U.A. no. 61 / 299,565 entitled "Thermal Energy Storage" and filed January 29, 2010, incorporated herein by reference. For example, the base sheet, the cover sheet, or both may be attached to one or more rings, such as one or more inner rings, one or more outer rings, or both. The substructure, if employed, may include a honeycomb or other open cell structure, as described in paragraph 83 of the patent application publication of E.U.A. no. 2009-02501 89 by Bank et al. , published October 8, 2009, incorporated herein by reference.

The thickness of the capsular structure is defined by the average separation between the top surface of the article (e.g., the top surface of the cover sheet) and the bottom surface of the article (e.g., the bottom surface of the base sheet). ). The article may have a geometry sufficiently thin so that heat can be rapidly delivered from a fluid to the thermal energy storage material and / or quickly removed from the thermal energy storage material to a fluid. The article may have a thickness that is less than the length or diameter of the article.

For example, the ratio of the length or diameter of the article to the thickness of the article may be about 2 or more, about 5 or more, about 10 or more, or about 20 or more. Without limitation, the ratio of the length or diameter of the article to the thickness of the article may be about 1,000 or less, preferably about 300 or less, and more preferably about 150 or less. Preferably, the thickness of the article is 80 mm or less, more preferably about 20 mm or less, still more preferably about 10 mm or less, and most preferably about 8 mm or less. Preferably, the thickness of the article is greater than about 0.5 mm, more preferably greater than about 1 mm.

Typically, the longest dimension of the article (e.g., the length or diameter of the article) is much greater than the thickness of the article so that the item can both have a large volume (e.g., to accommodate a large volume of material of thermal energy storage), and a large surface area (for example, for a rapid transfer of thermal energy). The longest dimension of the article is preferably greater than about 30, more preferably greater than about 50 mm and most preferably greater than about 1 00 mm. The longest dimension is defined by use, and may have any length that satisfies the need for heat storage, heat transfer, or both, in a particular use. Typically, the longest dimension of the article is less than about 2 m (i.e., 2, 000 mm), however, articles having a longer dimension greater than about 2 m may also be employed.

The article may have one or more side surfaces. For example, the article may have one or more side surfaces that are non-planar. The article may have a single side surface that is generally arched, generally non-planar, generally continuous, or any combination thereof. Preferably said one or more side surfaces are generally equidistant from a center of the article so that the article can be placed in a container having a generally cylindrical cavity with a diameter of the cavity that is just slightly larger than the average diameter of the article. When the ratio of the diameter of the cavity to the average diameter of the article is low, a large amount of the cavity is occupied by the article. For example, the ratio of the maximum diameter of the article to the average diameter of the article can be less than about 1.8, preferably less than about 1.2, more preferably less than about 1.1, and most preferably less than about 1.05. It will be noted that the ratio of the maximum diameter to the average diameter of the article is about 1.0 or more (eg, about 1001 or more).

A large portion of the volume of the capsular structure is the encapsulated volume (ie, the volume of said one or more sealed spaces) so that the article can contain a relatively large amount of the thermal energy storage material. The total volume of said one or more sealed spaces of the article is preferably at least about 50% by volume, more preferably at least about 80% by volume, even more preferably at least about 85% by volume and most preferably about 90% by volume based on the total volume of the article. Typically, the total volume of said one or more sealed spaces of the article is less than about 99.9% by volume based on the total volume of the article. The remaining volume, not occupied by the thermal energy storage material, can include or consist almost entirely of the capsular structure, empty spaces (for example, containing one or more gases), one or more structures to improve the heat transfer between the thermal energy storage material and the capsular structure, or any combination thereof. The structures for improving the heat transfer between the thermal energy storage material and the capsular structure include any structure formed of a material having a relatively high thermal conductivity (for example, in relation to the thermal energy storage material). which is capable of achieving increases in the rate of heat flow from the thermal energy storage material to a heat transfer fluid. Preferred structures for improving the heat flow rate include fins, metal mesh, projections in the sealed space, and the like.

Preferably, the article is easy to stack with other identical shaped articles, or other items that generally have a mating surface. For example, two articles to be stacked may have opposite surfaces which are generally mating surfaces so that when they are stacked, the two articles are nested together. It will be noted that one approach to stacking items so that they are easily nested together is to select a shape (eg, a shape of an arcuate surface, a shape of sealed spaces, or both) that has a high-order rotational symmetry . The rotational symmetry may be about an axis in the stacking direction (eg, an axis through the fluid conduit of the capsular structure). Typically, the order of rotational symmetry describes the number of different rotations between the two surfaces that are stacked jointly in which they will nest together. The order of the rotational symmetry of the article, the base sheet (eg, the arcuate surface of the base sheet), or both, is preferably at least 2, more preferably at least 3, even more preferably at least 5, and very preferably at least 7.

Preferably, the article has a capsular structure that is difficult to bend. For example, the capsular structure may be free of a cross section in which a cover sheet and a base sheet are in contact along most or even the entire length of the cross section (such as a diameter of the capsular structure). There are several approaches that can be used to ensure that the capsular structure will be difficult to bend, including selecting a configuration of the capsules in such a way that the order of rotational symmetry is not an even number, selecting a configuration of the capsules so that there is no rotational symmetry, selecting a capsule configuration that includes two or more capsule rings (such as concentric rings) that are rotated relative to each other such that each radial section includes at least one sealed space, or any combination of the same. It will be appreciated that other geometries and other means may be employed to make the capsular article resistant against bending. For example, the materials for the capsular structure may be chosen to be generally rigid, the structure may include one or more rods (e.g., in a tangential direction), and the like.

All the thermal energy storage material of the article may be in a single sealed space. Optionally, the thermal energy storage material of the article can be divided among a plurality of sealed spaces so that if a sealed space is punctured, or leaky, despite the improvements described herein, only a portion can be removed. of the thermal energy storage material. As such, the number of sealed spaces in the article (eg, sealed spaces that house the thermal energy storage material) can be 1 or more, 2 or more, 3 or more, 4 or more, or 5 or more. The upper limit on the number of sealed spaces is what is feasible and for a particular application is defined by the need of the application. However, the number of sealed spaces in the article is typically less than 1,000. However, it will be noted that very large items may have 1, 000 or more sealed spaces. For the same reasons, the volume fraction of the thermal energy storage material that is in any sealed compartment may be about 1 00%, less than about 55%, less than about 38%, less than about 29%, or less than about 21%, based on the total volume of thermal energy storage material in the article. Typically a sealed space includes at least 0. 1% by volume of the thermal energy storage material in the article. However, it will be appreciated that the article may include one or more sealed spaces that are substantially or even completely free of the thermal energy storage material.

Optionally, the sealed spaces can be configured in a pattern that facilitates efficient stacking of the articles of the invention and efficient energy transfer to and / or from the capsules, such as a plurality of concentric rings, including an innermost ring ( for example, a ring closer to an aperture periphery) and an outermost ring (eg, a ring closer to the outer periphery), each containing one or more sealed spaces. The spaces sealed in a ring can have a generally repetitive pattern. For example, each sealed space or each of the groups of 2, 3, 4 or more spaces sealed in a ring can generally have the same shape and size. The number of sealed spaces in each ring can be the same or different.

Preferably, the outermost ring has more sealed spaces than the innermost ring, the average length of the sealed spaces of the outermost ring is less than the average length of the sealed spaces of the innermost ring (where the average length is measured in the direction radial from the opening to the outer periphery), or both, so that the volume variation between the sealed spaces of the outermost ring and the innermost ring is reduced.

As described hereinafter, the article may be placed in a container, such as a container having a generally cylindrical shaped cavity. Preferably, the cavity may be only slightly larger in dimension than the longest dimension of the article. For example, the diameter of the container cavity may be just slightly larger than the diameter of the capsular structure of the article. The diameter of the cavity must be large enough so that the article can be inserted into the cavity. When the article (or a stack of articles) is placed in the container, it may be desirable for a fluid to flow between the outer periphery of the article and an inner wall of the container. This can be achieved by designing the ratio of the interior of the container and the shape of the article to create and maintain fluid flow paths. Any means can be used to create such fluid flow paths. As such, the article may optionally have one or more notches along its periphery (for example, the cover plate and the base plate may have one or more corresponding notches along their respective outer peripheries) of Alternatively, or additionally, the cavity of the container may have a surface with one or more slots for the flow of a fluid between the outer periphery of the article and the surface of the article. container. As another example, the diameter of the article can be small enough relative to the diameter of the interior of the cavity so that a fluid can flow along the entire outer periphery of the article. For example, the article may have one or more notches or the container may have one or more slots, for each space sealed in the outermost ring of the sealed spaces. A notch or slot can have any shape, such as a polygonal shape, an arched shape, a wedge shape, and the like, as long as it is large enough to allow the heat transfer fluid to flow. If used, the smallest dimension of the notches and / or grooves is typically at least about 0.1 mm). It will be appreciated that a combination of two or more means can be used to create a fluid flow path. For example, the article may have one or more notches along its outer periphery and the article may have a sufficiently small diameter so that the fluid may flow along its entire outer periphery when placed in a cavity.

The article for housing the thermal energy storage material includes a base sheet that is formed such that it includes one or more suitable hoppers to house a liquid. The base sheet can be used in a process in which one or more hoppers are filled with a thermal energy storage material., covered with a generally flat cover sheet and then attached to the cover sheet (preferably while the thermal energy storage material is at least partially in the molten state). Optionally, the base sheet may have one or more projections, so that when the article is stacked with another article having a mating surface generally with the base sheet, the two articles are only partially nested. As such, said one or more projections can function as a spacer to separate the coupling surfaces generally so that a fluid (eg, a heat transfer fluid) can flow between the coupling surfaces. If employed, the projections preferably only cover a small portion of the surface area of the base sheet such that said one or more projections practically do not interfere with the flow of the fluid. The height of the projections may be selected to define the height (e.g., the average height) of the flow path between the two generally mating surfaces.

The base sheet may further include one or more volume expansion elements and / or one or more reinforcement elements, such as one or more rods, one or more depressions, one or more chevrons or any combination thereof, which function to stiffen the base sheet. Surprisingly, it has been observed that the hoppers, the reinforcing elements, the volume expansion elements or any combination thereof of the base sheet can reduce the maximum tension in the base sheet when an article containing a material is heated of thermal energy storage. For example, the maximum stress, such as the maximum von Mises stress, in a base sheet may be less than the maximum von Mises stress of a flat cover sheet made of the same material (for example, the same metal) and which has the same thickness as the base sheet when heating the thermal energy storage material in a sealed space. The relatively low tension in the base sheet can provide an opportunity to reduce the weight of the article and / or increase the amount of thermal energy storage material in the article using a base sheet having a smaller thickness (e.g. a thickness that is less than the thickness of the cover sheet).

It has also been surprisingly observed that the thickness of the base sheet, the cover sheet, or both, can be further reduced by the addition of optional reinforcing elements, such as rods, depressions, or chevrons to the base sheet. If employed, the reinforcing elements preferably have a size, shape and number sufficient to reduce the maximum von Mises tension of the sheet (eg, the base sheet or the cover sheet), preferably by about 2% or more , more preferably at about 5% or more, and most preferably at about 10% or more. The reinforcing elements may include elements that are projecting (i.e., moving away from the sealed space), elements that are grooves (i.e., entering the sealed space), or both. The preferred reinforcing features protrude or embed a depth / height of about 0.2 mm or more, more preferably about 0.4 mm or more, and most preferably about 0.6 mm or more. Preferred reinforcing features protrude or embed a depth / height of about 5 mm or less, more preferably of about 3 mm or less, and most preferably of about 1 mm or less.

When articles are stacked, they can be configured in such a way that the cover sheets of two adjacent articles meet at least partially to each other. It may be desirable that the two cover sheets have a large contact area so that they have good thermal communication and / or that there are few spaces or spaces of gas between the two sheets of cover so that no space is wasted. As such, the cover sheets can only include slots. Good contact between two cover sheets can also be achieved by having cover sheets that are generally mating surfaces. For example, a first cover sheet may have one or more slots that engage with one or more projections of a second cover sheet and / or vice versa.

The base sheet and the cover sheet are joined so as to form a sealed space that includes a thermal energy storage material. The union of the base sheet and the cover sheet may include a main seal around one or more (e.g., all) of all the sealed places so that a sealed space is isolated from any other sealed space and / or from regions outside the article. The attachment of the base sheet and the cover sheet may include one or more secondary stamps, such as a seal isolating a sealed space from an outer region of the article and / or other sealed spaces in the event of a seal failure. principal.

Without limitation, preferable thermal energy storage materials for the heat storage device include materials that are capable of exhibiting a relatively high density of thermal energy such as sensible heat, latent heat, or preferably both. The thermal energy storage material is preferably compatible with the operating temperature range of the heat storage device. For example, the thermal energy storage material is preferably a solid at the lowest operating temperature of the heat storage device is at least partially a liquid (e.g., completely a liquid) at the maximum operating temperature of the heat storage device, it is not significantly degraded nor is it decomposes at the maximum operating temperature of the device, or any combination thereof. Preferably, the thermal energy storage material is not significantly degraded or decomposed when heated to the maximum operating temperature of the device for about 1,000 hours or more, or even for approximately 10,000 hours or more.

The thermal energy storage material can be a phase change material having a solid to liquid transition temperature. The solid to liquid transition temperature of the thermal energy storage material can be a melting temperature, a liquefaction temperature, or a eutectic temperature. The transition temperature from solid to liquid must be sufficiently high so that when the thermal energy storage material is at least partial or even practically in the liquid state in its entirety, sufficient energy is stored to heat said one or more objects to be heated to a desired temperature The solid-to-liquid transition temperature should be sufficiently low that the heat transfer fluid, said one or more objects to be heated, or both, are not heated to a temperature at which it can degrade. As such, the desired temperature of the solid to liquid transition temperature may depend on the object to be heated and the heat transfer method. For example, in an application that transfers stored heat to an engine (for example, an internal combustion engine) using a glycol / water heat transfer fluid, the maximum transition temperature from solid to liquid can be the temperature at which degrades the heat transfer fluid. As another example, the stored heat can be transferred to an electrochemical cell of a battery using a heat transfer fluid where the heat transfer fluid has a high degradation temperature, and the maximum transition temperature from solid to liquid can be determined by the temperature that degrades it, or else, the electrochemical cell fails. The solid-to-liquid transition temperature may be greater than about 30 ° C, preferably greater than about 35 ° C, more preferably greater than about 40 ° C, still more preferably greater than about 45 ° C, and most preferably greater than about 50 ° C. The thermal energy storage material may have a solid to liquid transition temperature of less than about 400 ° C, preferably less than about 350 ° C, more preferably less than about 290 ° C, still more preferably less than about 250 ° C. and most preferably less than about 200 ° C. It will be noted that depending on the application, the transition temperature from solid to liquid can be from about 30 ° C to about 100 ° C, from about 50 ° C to about 150 ° C, from about 100 ° C to about 200 ° C , from about 150 ° C to about 250 ° C, from about 175 ° C to about 400 ° C, from about 200 ° C to about 375 ° C, from about 225 ° C to about 400 ° C, or about 200 ° C C at approximately 300 ° C.

For some applications, such as transportation related applications, it may be desirable for the thermal energy storage material to efficiently store the energy in a small space. As such, the thermal energy storage material can have a high heat density of fusion (expressed in units of megajoules per liter), which is defined by the product of heat of fusion (expressed in megajoules per kilogram) and density ( measured at approximately 25 ° C and expressed in units of kilograms per liter). The thermal energy storage material can have a melt heat density greater than about 0.1 MJ / liter, preferably greater than about 0.2 MJ / liter, more preferably greater than about 0.4 MJ / liter and most preferably greater than about 0.6 MJ / liter. Typically, the thermal energy storage material has a melt heat density less than about 5 MJ / liter. However, thermal energy storage materials having a higher density of heat of fusion can also be employed.

For some applications, such as transportation related applications, it may be desirable for the thermal energy storage material to be lightweight. For example, the thermal energy storage material may have a density (measured at about 25 ° C) less than about 5 g / cm 3, preferably less than about 4 g / cm 3, more preferably less than about 3.5 g / cm 3 and very preferably less than about 3 g / cm3. The lower limit of density is what is feasible. The thermal energy storage material can 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 preferably greater than about 1.7 g / cm3.

The sealed spaces can contain any thermal energy storage material known in the art. Examples of thermal energy storage materials that may be employed in the compartments of thermal energy storage material include the materials described in Atul Sharma, V.V. Tyagi, C.R. Chen, D. Buddhi, "Magazine on thermal energy storage with materials and applications of phase change" ("Review on thermal energy storage with phase change materials and applications"), Renewable and sustainable energy journals (Renewable and Sustainable Energy Reviews ) 13 (2009) 318-345, and in Belén Zalba, José Ma. Marín, Luisa F. Cabeza, Harald Mehling, "Magazine on thermal energy storage with phase change: materials, heat transfer analysis and applications" ( "Review on thermal energy storage with phase change: materials, heat transfer analysis and applications"), Applied Thermal Engineering (Applied Thermal Engineering) 23 (2003) 251-283, both incorporated herein by reference in their entirety. Other examples of preferred thermal energy storage materials that can be employed in the heat transfer device include the thermal energy storage materials described in the patent application publications of E.U.A. num. 2009/0211726 (entitled "Thermal Energy Storage Materials" and published on August 27, 2009) and 2009/0250189 (entitled "Heat Storage Devices") and published on October 8, 2009), and paragraphs 54-63 of the US provisional patent application no. 61 / 299,565 (entitled "Thermal Energy Storage") and filed on January 29, 2010).

The thermal energy storage material may include an organic material, an inorganic material or a mixture of an organic and inorganic material having the solid-to-liquid transition temperature, the melting heat density, or both, has been described with earlier in the present. Organic compounds that may be employed include paraffins and non-paraffinic organic materials, such as fatty acid. Inorganic materials that may be employed include saline and metallic hydrates. The material of Energy storage can be a compound or a mixture (e.g., a eutectic mixture) having a transition from solid to liquid generally at a single temperature. The thermal energy storage material may be a compound or a mixture having a transition from solid to liquid through a range of temperatures (e.g., a range greater than about 3 ° C, or greater than about 5 °. C).

Without limitation, the thermal energy storage material may include one or more inorganic salts selected from the group consisting of nitrates, nitrites, bromides, chlorides, other halides, sulfates, sulfides, phosphates, phosphites, hydroxides, carbides, bromates, mixtures of the same and combinations thereof.

The thermal energy storage material may include (or may even consist essentially of or consist of) at least one first material with metal content, and more preferably a combination of said at least one first material with metal content and at least one second material with metal content. The first metal-containing material, the second metal-containing material, or both, can be a practically pure metal, an alloy such as one that includes practically pure metal and one or more additional alloying ingredients (eg, one or more than other metals), an intermetallic, a metal compound (eg, a salt, an oxide or otherwise) or any combination thereof. A preferred approach is to employ one or more materials with metal content containing materials as part of a compound metal; A more preferred approach is to employ a mixture of at least two metal compounds. By way of example, a preferred metal compound can be selected from oxides, hydroxides, compounds including nitrogen and oxygen (eg, nitrates, nitrites or both), halides or any combination thereof. It is possible that material systems of ternary, quaternary or other multiple components can also be used. The thermal energy storage materials herein may be mixtures of two or more materials exhibiting a eutectic.

The volume of the thermal energy storage material in said one or more sealed spaces of the article is sufficiently high so that the article can store a large amount of thermal energy storage material. The ratio of the volume of the thermal energy storage material contained in the article to the total volume of said one or more sealed spaces, the ratio of the volume of the thermal energy storage material to the total volume of the article, or both (the volumes measured at a temperature of about 25 ° C, or at a temperature at which the thermal energy storage material is a liquid) is preferably greater than about 0.5, more preferably greater than about 0.7, and most preferably greater than about 0.9. The ratio of the volume of the thermal energy storage material contained in the article to the total volume of said one or more sealed spaces, the ratio of the thermal energy storage material volume to the total volume of the article, or both (the measured volumes at a temperature of about 25 ° C, or at a temperature at which the thermal energy storage material is a liquid) is typically less than about 1.0 and more typically less than about 0.995.

The sealed space may include a volume containing a gas, such as air, N2, or an inert gas such as He, Ar, and the like, so that the thermal energy storage material may expand when heated. For example, the sealed space may have a region that lacks the thermal energy storage material at a temperature of about 25 ° C., such that after heating the energy storage material above its melting temperature, the thermal energy storage material may expand without forming holes in the cover sheet or the base sheet or causing it to Delamine one or more sheets. The volume of a sealed space lacking the thermal energy storage material (eg, the volume of the sealed space containing a gas) at 25 ° C, can be at least about 0.5%, preferably at least about 1%, and most preferably at least about 1.5%, based on the total interior volume of the sealed space.

The thermal energy storage material, the sealed space, or both may be virtually devoid of, or completely lacking, materials that are subjected to vaporization or sublimation when the article is used to store the heat so that the pressure in the sealed space does not increase a lot. For example, the thermal energy storage material, the sealed space, or both may be substantially free of materials that are subjected to vaporization or sublimation at a temperature of about 25 ° C to about 100 ° C, preferably about 25 ° C to about 150 ° C, more preferably from about 25 ° C to about 200 ° C and most preferably from about 25 ° C to about 300 ° C. As such, the thermal energy storage material, the sealed space, or both may be virtually waterless. In applications employing temperatures of about 100 ° C or more for the storage of thermal energy, it may be desirable for the sealed space to be substantially free of, or even completely free of water. If present the concentration of water in the sealed space may be about 5% by weight or less, more preferably about 1% by weight or less, even more preferably about 0.2% by weight or less, and most preferably about 0.1 in weight% or less.

Figure 1 is a drawing illustrating a portion of an article 2 having a capsular structure. A portion of the outer surface (bottom surface) of the base sheet 12 of the article is shown in Figure 1. The article includes a plurality of capsules 10. As shown in Figure 1, the capsules 10 can be placed in an array newspaper 11. The base sheet may have one or more hoppers 8, such as a hopper that can be used to hold the material of storage of thermal energy before and / or during the joining of a base sheet to a cover sheet. The base sheet also includes a flange region 6. The flange region can be used to join the base sheet to a cover sheet. As such, the flange region may be a region that is not covered with thermal energy storage material when the base sheet and the cover sheet are joined.

Figure 2A is a cross-sectional view of an illustrative capsular structure 2 including one or more sealed spaces 1 8. Figure 2B is a cross-sectional view of a single capsule, such as a capsular structure having a capsule 10 or a portion of a capsular structure 2 has a plurality of capsules 1 0. As illustrated in Figures 2A and 2B, the capsule 10 may be a sealed space 1 8 containing a thermal energy storage material 16 and optionally a space 20 or another space that generally lacks the thermal energy storage material. The article may include one or more primary seals 22, such as a seal isolating the sealed space 1 8 from an outer region of article 24, from other sealed spaces, or both. The article may include one or more secondary seals 22 'which may insulate the sealed space in the event of failure of a main seal 22. As illustrated in Figures 2A and 2B, the sealed space 1 8 may be formed by attaching a base sheet 1 2 around a region of flange 6 to a cover sheet 14 (for example, a cover sheet which is generally flat). The base sheet may also include a hopper region 8.

The thickness 1 3 of the base sheet can be reduced (for example, in relation to the thickness 15 of the cover sheet), due to the stiffness of the base sheet by the hoppers 8 '. The seals (for example, primary seal 1 1, secondary seal 22 ', or both) can be formed by welding the base sheet and the cover sheet, such as by laser welding.

Said one or more sealed spaces can be prepared by joining a metal cover sheet and a metal base sheet with one, two, or more welds, wherein the welds completely cover said one or more sealed spaces. An individual sealed space can be prepared using a single continuous weld, or a plurality of welds. The plurality of welds can form a continuous perimeter. The plurality of welds may be discontinuous. For example, an individual sealed space may have a weld along an outer perimeter and a second weld along an internal perimeter.

Figure 3 is a schematic diagram of a portion of a formed sheet 40 (eg, a base sheet 1 2) that can be used in an article 2 having a plurality of sealed spaces. The formed sheet may have an opening 46 (eg, a generally circular opening) near the center of the sheet. Figure 3 shows only about 1/4 of the formed sheet 40 and therefore, only 1/4 of the opening 46 is shown. Figure 3 shows the lower surface 41 of the formed sheet 40. The formed sheet has a plurality of hopper regions 8 and a plurality of flange regions 6. Hopper regions preferably provide hoppers 55 that are capable of containing thermal energy storage material. The hopper regions 8 may be configured in a plurality of hopper rings 50, 50 ', 50"As illustrated, the formed sheet may have an innermost ring of the bins 50 and an outermost ring of the bins 50'. The formed sheet may also have one or more additional 50"hopper rings, between the innermost and outermost rings of the bins 50, 50 '. As illustrated in Figure 3, some or all of the hoppers in a ring, or even all or some of the hoppers in the different rings may have approximately the same shape, approximately the same volume, substantially congruent, or any combination thereof. . It will be noted that the number of hoppers in the innermost ring of the hoppers can be greater than, less than or equal to the number of hoppers in the outermost ring of hoppers. Preferably, the number of hoppers in the innermost ring of the formed sheet 40 is smaller than the number of bins in the outermost ring, as illustrated in Figure 6. Some, or preferably all, of the hopper 8 regions have a region of flange 6 around the hopper region. As such, a hopper region 8 can be separated by the other hopper regions by a flange region 6. The formed sheet 40 can have an outer periphery 45, an inner periphery 47, or both. As illustrated in Figure 3, the formed sheet may have one or more notches 51 near the outer periphery 45. Said one or more notches may be used for the flow channels or flow paths along the outer periphery 45. Preferably, the outer perimeter of the lower surface of the formed sheet 40 has a generally circular shape (excluding one or more optional notches 51). As illustrated in Figure 3, the outer periphery 45, the inner periphery 47, and preferably both, may be flange regions 6.

Figure 4A illustrates a portion of a cover sheet 14 having 30 chevrons. The dimensions (eg, x, y, z, or any combination thereof) in Figure 4A may be in units of mm. The chevrons 30 may have a periodicity (in one or more directions) of about 3 mm or more, a periodicity of about 50 mm, or less, or both. The periodicity of the chevrons can be small enough so that the portion of a cover sheet on an individual sealed space has a plurality of chevrons 30. For example, the number of chevrons 30 on the region of a cover sheet 14 on a single The sealed space may be about 2 or more, about 5 or more, about 10 or more, about 20 or more, or about 30 or more. The chevrons 30 can have a periodicity of approximately 5 mm. The chevrons 30 can have a depth of about 0.2 mm or more, a depth of about 4 mm or less, or both. For example, the chevrons 30 can have a depth of about 1 mm. It will be noted that chevrons having a greater or lesser periodicity and / or a greater or lesser depth may also be employed. The dimensions (for example, x, y, z or any combination of the same) in Figure 4A may be in any arbitrary unit that is the same or different, or may be in units of mm. The chevrons may be in a section of the cover sheet covering a sealed space, in a region of a cover sheet that is outside sealed spaces, or both. It will be noted that chevrons may be employed in a base sheet, a cover sheet or both.

Figure 4B is a schematic view of an illustrative capsule 10 having a cover sheet 14 including depressions 32. Figure 4C is a top view of the portion of a cover sheet 14 on a single capsule, such as the illustrated capsule in Figure 4B. As illustrated in Figures 4Ba and 4C, the cover sheet 14 may include one or more depressions 32, and particularly one or more recesses 33 recessed. The depressions 32 can assume any configuration. For example, the depressions may have a brick wall pattern, so that adjacent rows of depressions are displaced. Preferably, the depressions have a periodicity of about 1 mm or more, more preferably about 2 mm or more, and most preferably about 3 mm or more. Preferably, the periodicity of the depressions is about 30 mm or less, more preferably about 15 mm or less, and most preferably about 10 mm or less. The periodicity of the depressions may be small enough so that the portion of a cover sheet on an individual sealed space has a plurality of depressions 32. For example, the number of depressions 32 on the region of a cover sheet 14 through a single sealed space may be about 2 or more, about 5 or more, about 10 or more, about 20 or more, or about 30 or more. Preferably, the depressions have a depth of about 0.1 mm or more, more preferably about 0.2 mm or more, even more preferably about 0.3 mm or more, even more preferably about 0.5 mm or more and most preferably about 0.5 mm or more. plus. Preferably, the depressions have a depth of about 3 mm or less, more preferably about 2 mm or less, and most preferably about 1 mm or less. It will be noted that depressions having a greater or lesser periodicity and / or a greater or lesser depth may be employed. The depressions 32 may be in a section of the cover sheet covering a sealed space, in a region of a cover sheet that lies outside of sealed spaces, or both. It will be noted that depressions may be employed in a base sheet, a cover sheet or both.

Figure 4D shows an illustrative diagram for viewing a portion of a sheet (e.g., cover sheet 14) that includes reinforcement elements. The reinforcing elements 34 can be configured in a generally random pattern. As illustrated in Figure 4D, the reinforcing elements 34 may have different shapes, different sizes, or both. The periodicity of the reinforcing elements may be small enough so that the portion of a cover sheet 14 on an individual sealed space has a plurality of reinforcing elements 34. For example, the number of reinforcing elements 34 on the region of a cover sheet 14 over a single sealed space may be about 2 or more, about 5 or more, about 10 or more, about 20 or more, or about 30 or more.

Figure 5A, 5B and 5C illustrate the pressure 36, 36 ', 36"in a sealed space 18', 1 8" 'at different temperatures and sealing at different sealing temperatures. As illustrated in Figure 5A, at the sealing temperature, the pressure to the interior 36 and the pressure to the exterior 38 of the sealed spaces 1 8 ', 18"may be approximately equal, as illustrated in Figure 5B, pressure inside 36 'of the sealed space 1 8' may be greater than the external pressure 38 when the sealing space 1 8 is sealed at low temperature and the article 2 is heated to a higher temperature As illustrated in the Figure 5B, there may be an outward net force 35 in the cover sheet 14 due to the pressure difference when the temperature is higher than the sealing temperature Figure 5C illustrates that the pressure inside 36"of the sealed space 1 8" it may be less than the external pressure 38 when sealed at a high high temperature and then reduce the temperature As illustrated in Figure 5B, there may be an inward net force 35 in the cover sheet 14 due to the difference in pressure when the temperature The temperature is below the sealing temperature.

Figures 6A, 6B and 6C show an illustrative example of a sheet (e.g., a cover sheet) including a rod structure 39 that includes projections and grooves. Figure 6A is a topographic drawing of the region of the sheet for a single capsule. Figure 6B is a photograph of a portion of a sheet including a plurality of the elements of Figure 6A. Figure 6C illustrates the effect of the structural elements of the forces on the sheet when a sealed space including the sheet is heated. As illustrated in Figure 6, the rods can be confined to the region of the topsheet that is around the sealed space. For example, the cover sheet may have a flange region that lacks rods or other reinforcement elements in the region where the cover sheet is bonded to a base sheet.

Figures 7A and 7B illustrate a sheet 60 (eg, a base sheet 1 2) that includes volume expansion elements 62 so that the sealed space is capable of increasing in volume as the storage material expands of thermal energy in the sealed space, and decrease in volume as the thermal energy storage material contracts. Figure 8A is a schematic diagram of a section of a base sheet 12 having a volume expansion element 62. As illustrated in Figure 7A, the volume expansion element 62 may include one or more wrinkles, such as plus one or more circumvolutions 64. The Volume expansion element may include a bellows. Figure 7A illustrates a volume expansion element 62 in a base sheet 12. However, it will be appreciated that the base sheet 1 2, the cover sheet 14 or both may include one or more volume expansion elements 62. The volume expansion element can operate by allowing a sheet to be reversibly shrunk in the sealed space. Figure 7B is a cross-section illustrative of a portion of a capsule 10 including the sheet 60 having the volume expansion element 62, a cover sheet 14, and the thermal energy storage material 16. The material The thermal energy storage 16 can be in a sealed space 18, which is sealed by a main seal 22, and preferably a secondary seal 22 '.

Figure 8 shows an illustrative relationship between the expected Von Mises peak voltage in a cover sheet when the capsule 10 is heated to about 250 ° C as a function of the thickness of the cover sheet 15. Figure 8 also shows the tension of the cover sheet. fluence of the metal used in the formation of the cover sheet. At a low thickness, the von Mises peak voltage is greater than the yield stress of the metal and the cover sheet can be defeated or cracked. With higher thicknesses, the von Mises peak voltage is less than the metal yield stress and the cover sheet does not expire or fail. Figure 9 shows an illustrative relationship between the expected Von Mises peak voltage in a cover sheet when the capsule is heated to about 250 ° C as a function of the thickness of the cover sheet 15 for cover sheets which are generally flat and for cover sheets having the structure of the rod shown in Figure 6. The thickness of the cover sheet required to avoid permanent deformation of the cover sheet can be reduced when a rod structure is employed. As such, the structure of the rod of Figure 6 may allow the articles and heat storage devices to be light, contain a greater amount of thermal energy storage material, or both.

The Fig. 10 shows an illustrative relationship between the expected Von Mises stress in a cover sheet when the capsule is heated to approximately 250 ° C as a function of the thickness of the cover sheet for sheets of glass. cover which are generally flat and for cover sheets having the structure of the rod shown in Figure 6, the gallon structure of Figure 4A, and the depression pattern of Figure 4B. The thickness of the cover sheet required to prevent permanent deformation of the cover sheet can be reduced when different reinforcing structures are used. As such, the structure of Figures 4A, 4B, and 6 may allow energy storage articles and devices that are lightweight, contain a greater amount of thermal energy storage material, or both.

Figure 1 1 illustrates a portion of the tooling 61 that may be employed in the preparation of a lamp (e.g., a cover sheet 14) having one or more reinforcement elements, such as one or more rods. Such tooling can be used in a process of print. It will be noted that a stamping process can be a continuous process or a batch process.

The articles that house the thermal energy storage material are preferably capable of being stacked with other identical articles or with a second article having generally a mating surface (such as a generally mating base sheet). The articles can be stacked in axial layers with a space between adjacent axial layers so that a heat transfer fluid can flow between the axial layers. An axial layer will generally contain one, two or more items. An axial layer (for example, each axial layer) preferably contains one or two articles. For example, an axial layer may have two articles that are in contact on a surface, such as a base surface or a cover surface, such that a fluid generally can not flow between the two articles). As such, some of the articles (e.g., each article except the articles at one end of a stack) may have a first surface (e.g., a base surface) that is generally in complete contact with a surface of a first adjacent article so that a fluid can not flow along the first surface, and a second surface that is separated from a second adjacent article (eg, having an opposite surface that is generally a mating surface with the second surface) so that a fluid can flow along some, most or even all of the second surface. The spacing between two adjacent axial layers may be due to any means of spacing known in the art. By way of example, preferable spacing means includes one or more projections on a surface of at least one of the articles, a spacer material between the two layers, a capillary structure between two layers, or any combination thereof. Preferably, the second surface of the article has a generally arcuate shape and the article is partially nested with the second adjacent article. The spacing between the two articles that are partially nested preferentially is generally constant (except for the projections or other spacers that cause the separation of the adjacent articles). It will be noted that the stacking of the articles may include a step of rotating an axial layer (eg, rotating an article), or, configuring it so that the axial layer is at least partially nested with an adjacent axial layer. The flow of a fluid between two opposite surfaces of two adjacent axial layers will generally be in a radial direction and can be described as a generally radial flow. Each pair of axial layers that are separated from each other will have a radial flow path. Typically, the article stack will have a plurality of radial flow paths (e.g., 2, 3, or more). Two or more (for example, each radial flow path can have the same flow length, the same thickness, the same cross-sectional shape, or any combination of the same, for example, two or more (for example, all ) of the radial flow paths can be congruent, it will be noted that if the aperture (is say, the fluid conduit) is located at the center of the article, the radial flow path can generally be symmetric, regardless of the direction of flow.

When stacked (for example, in a stack containing 3, 4 or more articles), each of the articles preferably has at least one opening corresponding to an opening of each of the other articles (except possibly one article in 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 as it flows through each of the corresponding openings of the articles interposed between the first and last article without flowing between articles adjacent (that is, without a generally radial flow). The flow through the openings will generally be in an axial direction and can be described as a generally axial flow.

As described above, the article stack can define a central axial flow path (e.g., through the central axis formed by the article openings) and one or more radial flow paths that are generally perpendicular to the path of central axial flow.

Generally, the article stack is packaged tightly (eg, except for radial flow paths) so that the article stack is compact and contains a large amount of thermal energy storage material. As such, the radial flow path has a height (in the direction between the adjacent articles), for example, an average height, which is generally small. The The height of the radial flow path is preferably less than about 1 5 mm, more preferably less than about 5 mm, even more preferably less than about 2 mm, even more preferably less than about 1 mm, and most preferably less than about 0.5 mm . Typically, the height of the radial flow path is usually large enough so that the fluid can flow through the path. Typically, the height (eg, the average height) of the radial flow path is greater than about 0.001 mm (eg, greater than about 0.01 mm).

Figure 1 2 illustrates an aspect of the invention that includes a plurality of articles 2, each having one or more sealed spaces 18 for housing a thermal energy storage material 16 configured to form a stack of articles 70. items 2 may include a formed sheet, such as a base sheet 12 having a generally arcuate surface 41. The surface 41 of an article can generally be coupled with the surface of a second article. The items can be configured so that the adjacent items are partially nested together. The articles illustrated in Figure 1 2 have an inner ring of 9 generally identical capsules and an outer ring of 1 7 generally identical capsules. The items illustrated in Figure 1 2 have a rotational symmetry of order 1 and therefore have only 1 position in which two facing items will be partially nested.

In order to facilitate the stacking of articles, each article may have one or more location elements. It will be noted that articles with a greater order of symmetry can be used. For example, the article may have a single capsule ring (or even a single capsule), or the article may have a first ring of capsules having an integral multiple of capsules (e.g., 1, 2, 3, or more) for each capsule of a second ring of capsules. As illustrated in Figure 1 2, the articles 2 can have a generally circular cross section (e.g., in a direction perpendicular to the stacking direction). The outer periphery of each article may have a plurality of notches 51 that are large enough to allow a fluid to flow. The articles 2 may have sealed spaces 74 configured in one or more concentric rings of sealed spaces. Each article 2 may have a fluid conduit 46. The fluid conduit 46 may be generally located near the center of the articles 2 so that when the articles are stacked (eg, stacked in an axial direction), a trajectory of axial flow 84. Axial flow path 84 preferably includes a fluid conduit 46 of each article 2.

Figure 1 3 illustrates an article 2 that includes an odd number of 1 0 capsules. The article may have an odd rotational symmetry, so that it can not easily deform around a diameter. The article 2 can have a generally circular cross section with one or more openings 46 in the center of the article. The opening 46 can be generally circular. As illustrated in Figure 1 3, one or more, or even each of the sealed capsules or spaces may have a main seal 22 that isolates the sealed space from the exterior of the article. The article may also have one or more secondary stamps 22 '. The secondary seal may include a seal near an inner periphery 47 (ie, an opening periphery) of the article, a seal near an outer periphery 45 of the article, or both. The secondary seal 22 'may be sufficient to prevent leakage of a thermal energy storage material 1 6 from a sealed space 1 8 if a major seal 22 fails.

The articles (e.g., a stack of articles) described herein may be employed in a heat storage device. The heat storage device may include a container or other housing having one or more orifices for flowing a heat transfer fluid in the container and one or more orifices for flowing a heat transfer fluid out of the container. The heat storage device has one or more heat transfer fluid compartments. Preferably, the heat storage device includes a single compartment of heat transfer fluid. A heat transfer fluid compartment can include or consist essentially of a contiguous space in the container between the inlet and outlet, where the heat transfer fluid can flow. Preferably, the container is at least partially insulated so that heat losses from the container to the environment can be reduced or minimized.

The heat storage device can be designed to accommodate a high concentration of thermal energy storage material, so that it can transfer thermal energy between a heat transfer fluid and the fast thermal energy storage material. and evenly, so that it can store heat for a long time, or any combination thereof.

The interior of the container of the heat storage device can have any shape capable of housing a stack of articles. Preferably, the shape of the interior of the container is such that the stack of articles occupies a large portion of the interior volume of the container. The ratio of the total volume of the thermal energy storage material (e.g., measured at about 25 ° C) housed in the sealed spaces of the articles in the container to the total internal volume of the container (e.g., at a temperature of about 25 ° C) may be greater than about 0.3, preferably greater than about 0.5, more preferably greater than about 0.6, even more preferably greater than about 0.7 and most preferably greater than about 0.8. The upper limit on the volume of thermal energy storage material in the vessel is the need for space for a heat transfer fluid that contacts the articles to transfer thermal energy. The ratio of the total volume of thermal energy storage material (eg, measured at approximately 25 ° C) housed in the sealed spaces of the articles in the container to the total interior volume of the container (for example, at a temperature of about 25 ° C) may be less than about 0.99, preferably less than about 0.95.

The heat storage device has a heat transfer fluid compartment for flowing one capable of housing a heat transfer fluid as it flows through the device. Preferably, the heat transfer fluid compartment is connected to one or more orifices (eg, one or more inlets) to flow a heat transfer to the heat transfer fluid compartment. Preferably, the heat transfer fluid compartment is connected to one or more orifices (e.g., one or more outlets) to flow a heat transfer out of the heat transfer fluid compartment. The heat transfer fluid compartment may be a space defined at least partially by one or more heat transfer fluid compartment walls, a space defined at least partially by one or more articles, a space defined at least partially by a housing or container of the heat storage device, or any combination thereof.

The heat transfer fluid compartment defines the flow path of a heat transfer fluid through the heat storage device. The heat transfer fluid compartment includes a generally axial flow path through the openings in the article stack. The heat transfer fluid compartment includes a generally radial flow path between two adjacent articles. It will be noted that the radial flow may be an inward flow from an outer periphery towards the opening of an article, or an outward flow from an opening towards the outer periphery of an article. The heat transfer fluid compartment includes a flow path having a generally axial component (and optionally, a tangential component) between an outer periphery of the article and a wall of the container. Preferably, the combined radial flow paths have a relatively high hydraulic resistance. For example, the combined radial flow paths have a hydraulic resistance that is greater than (more preferably at least twice greater than) the hydraulic resistance of the central axial flow path, the external axial flow path or both.

Preferably, the heat transfer fluid compartment has sufficient thermal communication with the sealed spaces that house the thermal energy storage material so that it can remove heat or provide heat to the thermal energy storage material. Preferably, the heat transfer fluid compartment is in direct thermal communication with one or more (or more preferably all) of the sealed spaces. A direct thermal communication can be any shortest distance path between a sealed space and a portion of the heat transfer fluid compartment that lacks a material having low thermal conductivity. Materials of low thermal conductivity include a thermal conductivity less than about 100 W7 (m K), preferably less than about 10 W / (m K) and most preferably less than about 3 W / (m K). For example, the heat transfer fluid or the heat transfer fluid compartment can be contacted with a wall of one or more (or preferably all) of the seals, or be separated from the spaces sealed practically or completely by materials that they have a high thermal conductivity (eg, greater than about 5 W / (m K), greater than about 1 2 W7 (m K), or greater than about 1 1 0 WV (m-K).

Preferably, the heat transfer fluid compartment is in direct thermal communication with one or more (or more preferably all) sealed spaces in the heat storage device. Lina direct thermal communication can be any shortest distance path between a heat transfer fluid compartment and a portion of the thermal transfer fluid compartment that lacks a material having low thermal conductivity. For example, the heat transfer fluid or the heat transfer fluid compartment may be contacted with a wall of one or more (or preferably all) of the enclosed spaces (such as a base sheet or cover sheet). ), or be separated from spaces sealed practically or completely by materials having a high thermal conductivity (eg, greater than about 5 W / (m K), greater than about 12 W / (m K) or greater than about 110 WV (m'K) It will be noted that a very thin layer (eg, less than about 0.1 mm, preferably less than about 0.01 mm, and more preferably less than about 0.001 mm) of a material having a low thermal conductivity may be between the heat transfer fluid compartment and a compartment of thermal energy storage material without significantly affecting the heat transfer.

The size and shape of the sealed spaces and / or articles may be chosen to maximize heat transfer to and from the phase change material housed in the capsules. The average thickness of the article can be relatively short so that the heat can escape quickly from the center of the sealed space. The average thickness of the article, sealed space, or , may be less than about 100 mm, preferably less than about 30 mm, more preferably less than about 10 mm, even more preferably less than about 5 mm and most preferably less than about 3 mm. mm. The average thickness of the article, the sealed space, or , may be greater than about 0.1 mm, preferably greater than about 0.5 mm, more preferably greater than about 0.8 mm and most preferably greater than 1.0 mm.

Preferably, the articles have a relatively high surface area to volume ratio so that the contact area with the heat transfer fluid is relatively high. For example, the article may have a surface that maximizes contact with a heat transfer fluid compartment, the article may have a geometry that maximizes heat transfer between the capsule and the heat transfer fluid compartment or . The ratio of the total surface area of the interface between the heat transfer fluid compartment and the articles in the heat storage device to the total volume of the thermal energy storage material in the heat storage device may be greater than about 0.02 mm "1, preferably greater than about 0.05 mm" 1, more preferably greater than about 0.1 mm '1, even more preferably greater than about 0.2 mm "1 and most preferably greater than about 0.3 mm' 1.

The heat storage device has a container for housing the stack of articles. The article stack can be housed in one or more cavities of the container. Without limitation, examples of containers that may be employed include those described in the patent application publication of E.U.A. no. 2009-021 1726 (published August 27, 2009), PCT Application no. PCT / US09 / 67823 (filed December 14, 2009), and provisional application of E. U.A. no. 61/299, 565 (filed on January 29, 2010). Preferred containers may have one or more holes (for example, one or more entries) to make flow a heat transfer fluid into the cavity of the container and one or more orifices (e.g., one or more outlets) to flow a heat transfer fluid out of the cavity of the container. The inlet and outlet may be on the same side or on different sides (eg, opposite sides) of the heat storage device. In addition to the orifices, the container is preferably sealed or constructed in such a way that a fluid flowing through the container does not escape from the container, so that a fluid flowing through the container may have a pressure greater than the ambient pressure. or .

The heat storage device can be used in applications that require storing heat for long periods of time, storing heat in a generally cold environment (e.g., an environment having a temperature of less than about 0 ° C, or even less than about - 30 ° C), or . Preferably, the heat stored in the heat storage device is slowly lost to the environment. Therefore, a certain form of isolation is preferably used in the present invention. The better the insulation of the system, the longer the storage time will be.

Any known form of insulation that reduces the rate of heat loss by the heat storage device can be used. For example, any isolation can be employed as described in the patent of E. U.A. no. 6,889,751, which is incorporated herein in its entirety by reference.

Preferably, the heat storage device is a insulated container (thermally), such that it is insulated on one or more surfaces. Preferably, some or all of the surfaces that are exposed to the environment or to the exterior will have an adjacent insulation. The insulation material can work by reducing heat loss by convection, reducing radiant heat loss, reducing conductive heat loss or any combination. Preferably, the insulation can be through the use of an insulation material or structure that preferably has a relatively low thermal conduction. The insulation can be obtained by using a space between the opposite spaced walls. The space may be occupied by a gaseous medium, such as an air space, or possibly it may even be an evacuated space (for example, by using a Dewar flask), a material or a structure having a low thermal conductivity , a material or structure having a low heat emissivity, a material or structure having low convection or any combination thereof. Without limitations, the insulation may contain ceramic insulation (such as quartz or glass insulation), polymer insulation or any combination thereof. The insulation may assume a fibrous form, a foam form, a densified layer, a coating or any combination thereof. The insulation can take the form of a woven material, a knitted material, a nonwoven material or a combination thereof. The heat transfer device can be isolated using a Dewar bottle, and more specifically, a container that includes generally opposite walls configured to define an interior storage cavity, and a wall cavity between the opposite walls, wall cavity which it is evacuated at a pressure lower than atmospheric pressure. In addition, the walls may use a coating on the reflective surface (eg, the surface of a mirror) to minimize radiant heat losses.

Preferably, vacuum insulation is provided around the heat storage device and / or the heat storage system. More preferably, vacuum insulation is provided, as described in the E .U.A patent. no. 6,889,751, incorporated herein by reference in its entirety.

The heat storage device may optionally include one or more compaction means for a stack of articles so that the separation between the layers is generally maintained. The compaction means may be any means capable of applying a compressive force to the stack of articles. The compression force must be large enough so that two items do not rotate with respect to each other, do not move axially relative to one another, or both. The compression force may be low enough so that an article does not deform or crack permanently or both. The preferred means of compaction will allow some changes in the thickness of the articles as the thermal energy storage temperature changes, as the thermal energy storage material changes between a solid and a liquid phase or both. By way of example, said one or more compaction means may include one or more springs above the article stack, one or more springs below the article stack or both. Without limitation, a compaction means such as a spring may be employed to reduce or minimize the change in thickness of a radial flow path between two adjacent articles when the thermal energy storage material is heated, undergoes a phase transition (such as a transition from solid to liquid) or both.

The heat storage device may have a plurality of flow paths for the flow of a heat transfer fluid through the device. Each flow path may include at least one radial flow between two adjacent articles. Preferably two or more (for example, each) of the flow paths through the heat storage device has a similar overall length, a similar total hydraulic resistance or both. Without limitation, the heat storage device may include one or more seals, one or more plates, one or more connectors or one or more flow paths for a heat transfer fluid as described in the patent application publication of USA no. 2009-021 1 726 (published on August 27, 2009), PCT application no. PCT / US09 / 67823 (filed December 14, 2009) and provisional application of E. U.A. no. 61/299, 565 (filed on January 29, 201 0).

The capsular structure and the articles that house the thermal energy storage material can be formed using any method that provides encapsulation of the thermal energy storage material. Without limitation, the process may employ one or any combination of the following: cutting or piercing an opening (eg, a hole) through a cover sheet, cutting or puncturing an opening (eg, a hole) a Through a base sheet (e.g., a thin sheet such as a sheet), form (e.g., thermoforming, embossing, embossing, or deformation) a base sheet to define a pattern on the sheet including the minus a depression or hopper region, form a base sheet to define a pattern in the sheet that includes one or more flange regions and one or more hopper regions, cut or perforate an outer periphery (e.g., an outer periphery generally circular) on a base sheet, cutting or perforating an outer periphery (eg, a generally circular outer periphery) on a cover sheet, filling a hopper (eg, a hopper formed from the cover). a base sheet) with a thermal energy storage material, cover a hopper (eg, a filled hopper) with a cover sheet, seal a cover sheet (eg, to a base sheet) in a manner such that one or more sealed spaces are formed which house the thermal energy storage material, seal a base sheet along an outer periphery, hermetically join a base sheet along an opening periphery, join sealing a cover sheet (eg, to a base sheet) along an aperture periphery, or hermetically bonding a cover sheet (eg, to a base sheet) along an outer periphery. The process for forming the article preferably includes a step of embossing, embossing, or thermoforming a base sheet. The process for forming the article may employ one or more steps of the process for producing a capsule described in the E patent application. U .A. no. 12/389, 598 entitled "Heat Storage Devices" and filed on February 20, 2009. The method for forming the article may optionally include one or any combination of the following: tightly bond a sheet base to one or more substructures such as an inner ring, an outer ring or both; sealingly attaching a cover sheet to one or more substructures such as an inner ring, an outer ring or both; or cutting, stamping or punching one or more notches along the outer periphery of a base sheet and / or a cover sheet. Figure 1 5 is a photograph of illustrative tooling that can be used to stamp a sheet (eg, a base sheet). Figure 1 5 illustrates a sheet 5 placed in the tooling 61 before forming the sheet 5 in a base sheet 1 2.

The process for preparing a cover sheet, a base sheet, or both, may include one or more stamping steps or otherwise to form the sheet such that it includes one or more reinforcing elements such as one or more depressions. , one or more rods, one or more chevrons, or any combination thereof.

The process for preparing an article may include a step for filling a base sheet with a thermal energy storage material. The base sheet can be filled when the thermal energy storage material is in the solid state or in the molten state. Preferably, the base sheet is filled with the thermal energy storage material in the molten state. As such, the process may include a step for heating and / or melting a thermal energy storage material.

The process for preparing an article may include a step for joining a topsheet and a base sheet so as to form one or more sealed spaces. The joining step may include a step to form a main seal. Preferably, the joining step includes both a step for forming a main seal and a step for forming a secondary seal. Preferably, the bonding step occurs while the thermal energy storage material is in the molten state. For example, the joining step can occur when the thermal energy storage material is at a temperature of about 1000 ° C or more, about 150 ° C or more, about 200 ° C or more, about 250 ° C. or more, or approximately 300 ° C or more.

The process for preparing an article can include a step for partially attaching a base sheet and a cover sheet to form a partially sealed space that can accommodate a liquid when the base sheet and the cover sheet are not in a generally horizontal orientation. A space between the base sheet and the cover sheet can be filled at least partially by inserting one end of a nozzle into the space to be filled and pumping thermal energy storage material (preferably, in the molten state) through the nozzle and in the partially sealed space. Therefore, the space between a base sheet and a cover sheet can be filled at least partially while the sheets are in hoppers in the base sheet can be filled while the base sheet is generally vertical. It will be noted that such an approach to filling a space with thermal energy storage material can produce a larger volume of thermal energy storage material. For example, the volume percentage of a sealed space that is occupied by air or another gas may be about 8% or less, about 6% or less, about 5% or less, about 4% or less, about 3% or less, about 2% or less, or about 1% or less. This approach to filling a space can also be used to fill a space between two base sheets. As such, the cover sheet can be a second base sheet. After filling a space with thermal energy storage material, the remainder of the main seal can be formed such that the filled space is a sealed space. With respect to a secondary seal, where appropriate, at least a portion of the secondary seal (e.g., in the region where a nozzle is inserted) is not formed until after the thermal energy storage material is inserted. in the space.

An article having a plurality of sealed spaces can be filled by a process that includes one or more of the following steps: partially sealing one or more spaces (e.g., attaching a base sheet and a cover sheet, or joining two sheets base) forming a portion of a main seal, inserting the thermal energy storage material in said one or more spaces, forming the rest of the main seal (for example, so that the space is sealed), turning the article that is filling, inserting the thermal energy storage material into one or more additional spaces having a portion of a main seal, and forming the remainder of the main seal of said one or more additional spaces.

Figure 16 illustrates an example of an article 2 having one or more (e.g., four) capsules 10 that have been filled with thermal energy storage material and one or more (e.g., a fifth space) that is filled . The filled space may have a partial primary seal 74. The filled space may optionally include a secondary secondary seal 75. Preferably, the filled space has a filling region 76 that does not have a complete primary seal 22 and does not have a complete secondary seal 22 '. The sealed space can be filled using a nozzle 77 that is insertedor, that is placed in the filling region 76. It will be noted that the nozzle can be placed in the filling region before, during, or after forming the partial main seal 74. As illustrated in Figure 1 6, it can be a nozzle 77 is inserted into the upper part of the space that is filled, so that the storage material of thermal energy 16 does not leak from filling region 76. After inserting thermal energy material 16 into the filled space, the process may include one or more of the following steps: removing the nozzle (preferably before turn the article), form the rest of the main seal (preferably before turning the article), or form a secondary seal or the rest of a secondary seal. As such, the article can be prepared using a machine that is capable of 1) forming a partial primary seal between two sheets (e.g., laser welding the two sheets), 2) injecting the thermal energy storage material (e.g. , in the molten state) in a space between the two sheets, 3) complete the main seal. If a plurality of sealed spaces is desired, the process may include one or more steps to rotate the sheets so that another space can be filled between the sheets.

Suitable sheets for encapsulating the thermal energy storage material include any thin metal sheets (eg, sheet metal) that are durable, corrosion resistant, or both, such that the sheet is capable of accommodating the material of thermal energy storage, preferably without leakage. The metal foils may be capable of operating in a vehicle environment with repeated thermal cycling for more than 1 year and preferably more than 5 years. The metal sheet, otherwise, may have a substantially inert outer surface which contacts the thermal energy storage material in operation. The outer surface of the metal foil that contacts the thermal energy storage material must include or consist essentially of one or more materials that do not significantly react with, corrode with, or both, when placed in contact with the storage material of thermal energy. Without limitation, exemplary metal foils that may be employed include metal foils having at least one layer of brass, copper, aluminum, nickel-iron alloy, bronze, titanium, stainless steel or the like. The sheet can be a noble metal in general or it can be one that includes a metal having an oxide layer (for example, a native oxide layer or an oxide layer that can be formed on a surface). An exemplary metal foil is an aluminum sheet comprising an aluminum or an aluminum-containing alloy layer (for example, an aluminum alloy containing more than 50% by weight of aluminum, preferably greater than 90%). in weight of aluminum). Another metal sheet by way of example is stainless steel. Preferable stainless steels include austenitic stainless steels, ferritic stainless steels or martensitic stainless steels. Without limitation, stainless steel may include chromium in a concentration greater than about 10% by weight, preferably greater than about 13% by weight, more preferably greater than about 15% by weight, and most preferably greater than about 17% by weight. The stainless steel may include carbon at a concentration of less than about 0.30% by weight, preferably less than about 0.15% by weight, more preferably less than about 0.1 2% by weight, and most preferably less than about 0.10% by weight. For example, stainless steel 304 (SAE designation) containing 1 9% by weight of chromium weight and approximately 0.08% by weight of carbon. Preferred stainless steels also include stainless steels with molybdenum content such as 31 6 (SAE designation). The metal sheet can have any coating known in the art which can reduce or eliminate the corrosion of the metallic lamp.

The metal sheet has a sufficiently high thickness so that holes or cracks are not formed when forming the sheet, when filling the capsules with thermal energy storage material, during the use of the capsules, or any combination thereof. For applications such as transport, the metal sheet is preferably relatively thin such that the weight of the heat storage device is not greatly increased by the metal sheet. The thickness of the metal foil can be greater than about 10 μ? , preferably greater than about 20 μ? , and more preferably greater than about 50 gm. The metal sheet may have a thickness of less than about 3 mm, preferably less than 1 mm, and most preferably less than 0.5 mm (eg, less than about Q.25 mm).

Figure 14 illustrates a cross section of a heat storage device 80 by way of example having a plurality of articles 2", and 2" ', each thermal energy storage material 16 encapsulated in a plurality of spaces sealed 1 8. The articles are configured in an insulated container 82 which may have a generally cylindrical shape. The device includes an article 2"having a first adjacent article 2" '(a) and a second adjacent article 2"' (b). Article 2" and its first adjacent article 2"'(a) can be configured with the upper surfaces (i.e., outer surfaces) of their respective flat cover sheets generally in contact The article 2"and the second adjacent article 2" '(b) may have generally mating surfaces (e.g. their respective base sheets may be generally mating surfaces) and may be configured so as to be partially nested together A spacer (not shown) may be used to maintain a distance between article 2"and its adjacent second item 2" '(b ) so that a heat transfer fluid can flow through a radial flow path 83 in a generally radial direction between the two articles, 2"and 2" '(b). 2"and the second adjacent article 2" '(b) may be formed from one of the sheets of article 2. As illustrated in Figure 14, each article may have a surface (e.g., a surface of the sheet base) which is capable of being contacted with a heat transfer fluid so that the heat transfer fluid can be in direct contact with each article and preferably each sealed space. As illustrated in Figure 14, each radial flow path 83 may have the same length, the same cross section, or may even be congruent.

Each article 2 may have an opening 46 near its center. The openings can be part of a compartment that allows it to flow to a heat transfer fluid through the device. The articles 2"and 2" 'can be configured so that their openings form a central axial flow path 84. The space between the outer periphery of the articles 2"and 2"' and the inner surface of the container 85 is also part of the heat transfer fluid compartment and an outer axial flow path 86 is formed. The heat storage device may have a first orifice 87 which is in fluid connection with a central axial flow path 84. The storage device of heat 80 may have a first seal or plate 88 separating a first hole 87 from the external axial flow path 86. The container 82 may have a second hole 89 that may be on the same side of the container as the first hole 87, or on a different side of the container, as illustrated in Figure 14. The heat storage device may have a second seal 90 that separates the second orifice 89 from the central axial flow path. The first seal, the second seal, or both, can prevent a fluid from flowing between the two axial flow paths 84 and 86, without flowing through a radial flow path 83. Preferably, the container 82 is insulated. For example, the container may have an inner wall 91 and an outer wall 92. The space between the two walls 93 may be evacuated or filled with an insulating material having low thermal conductivity. The device may also have one or more springs, such as one or more springs of compression 94, which exert a compressive force on the article stack.

Figure 14 illustrates a heat storage device 80 having two holes 87 and 89 on one side of the container. Such a device may employ a tube 95 which is connected to the first orifice 87 for fluid to flow between the first orifice and a region 96 of the central axial flow path 84 furthest from the first orifice. With reference to Figure 14, the first seal 88 and the second seal 90 can be employed to prevent a fluid from flowing from the first orifice 87 to the second orifice 89 without first flowing a radial flow path 83. By selecting the sizes for the two flow paths axial 84 and 86, the heat storage device 80 can be characterized as a Tichelmann system.

The pressure in one or more, or even all the sealed spaces may be less than atmospheric pressure, for example, under a vacuum, when the temperature is about 25 ° C. For example, the pressure in a sealed space at 25 ° C may preferably be about 600 Torr or less, about 500 Torr or less, about 400 Torr or less, about 300 Torr or less, or about 1 Torr or less. A vacuum in a sealed space can result from the application of a vacuum when the cover sheet and the base sheet are hermetically joined, as a result of sealingly joining the cover sheet and the base sheet when the storage material of the cover sheet and the base sheet is sealed. Energy is at an elevated temperature, or both. For example, the process to join hermetically the base sheet and the cover sheet may include a step to apply a vacuum of approximately 600 Torr or less, approximately 500 Torr or less, approximately 400 Torr or less, approximately 300 Torr or less, approximately 200 Torr or less, approximately 1 00 Torr or less, or approximately 50 Torr or less to a hopper region of a base lamp.

The heat storage device can be used in a heat storage system that employs one or more heat transfer fluids to transfer the heat to the thermal energy storage material, to transfer the heat out of the heat storage device or both The heat transfer fluid used to transfer heat to and / or out of the thermal energy storage material can be any liquid or gas, so that the fluid flows (eg, without solidifying) through the storage device of the heat transfer fluid. heat and the other components (for example, a component that provides heat, one or more connecting pipes or tubes, a heat extraction component, or any combination of these) through which it circulates when it is cold. The heat transfer fluid can be any heat transfer fluid or refrigerant known in the art that is capable of transferring heat to the temperatures employed in the heat storage device. The heat transfer fluid can be a liquid or a gas. Preferably, the heat transfer fluid is able to flow at the lowest operating temperature at which it can be exposed during use (eg, the lowest ambient temperature expected). For example, the heat transfer fluid may be a liquid or gas at a pressure of about 1 atmosphere and a temperature of about 25 ° C, preferably about 0 ° C, more preferably -20 ° C, and most preferably at about -40 ° C. Without limitation, a preferred heat transfer fluid for heating and / or cooling said one or more electrochemical cells is a liquid at about 40 ° C.

The heat transfer fluid must be capable of transporting a large amount of thermal energy, typically as sensible heat. The heat transfer fluid can have a specific heat (measured, for example, at about 25 ° C) of at least about 1 J / g K, preferably at least about 2 J / g K, even more preferably at least about 2.5 J / g K, and most preferably at least about 3 J / g K. Preferably, the heat transfer fluid is a liquid.

The heat transfer fluids and operating fluids that may be employed include those described in the patent application of E.U.A. publication 2009-02501 89 (published on October 8, 2009) and the PCT application no. PCT / US09 / 67823 (filed December 14, 2009). For example, any engine coolant known in the art can be used as a heat transfer fluid. Preferably, the system employs a single heat transfer fluid to transfer heat to the thermal energy storage material in the heat storage device and to remove heat from the thermal energy storage material in the storage device. hot. Alternatively, the system can employ a first heat transfer fluid to transfer heat to the thermal energy storage material and a second heat transfer fluid to remove heat from the thermal energy storage material.

Without limitation, heat transfer fluids that may be used alone or as a mixture include heat transfer fluids known to those skilled in the art and preferably include fluids containing water, one or more alkylene glycols, one or more polyalkylene glycols, one or more more oils, gno or more refrigerants, one or more alcohols, one or more betaines or any combination thereof.

The heat storage system may optionally include one or more heaters. The heater can be any heater capable of increasing the temperature of the thermal energy storage material in the heat storage device at a temperature above its transition temperature. The heater can be any heater that converts the energy (eg, electrical energy, mechanical energy, chemical energy, or any combination thereof) into heat (ie, thermal energy). Said one or more heaters may be one or more electric heaters. Said one or more heaters can be used to heat part or all of the energy storage thermal in the heat storage device. Preferably, the system includes one or more heaters that are in thermal communication with a heat storage device. For example, the system may include one or more heaters within the insulation of a heat storage device, and an electric heater may employ electricity from one or more electrochemical cells, from an external source, or both. For example, when a vehicle is connected to an outlet connected to a stationary object, the heat storage device can be maintained at a temperature higher than? ßG? ? ß G ?? G? of fusion of the thermal energy storage material in the heat storage device using the electricity coming from an external source. When the vehicle is not connected to an outlet connected to a stationary object, the heat storage device can be maintained at a temperature above the melting temperature of the thermal energy storage material in the heat storage device using electricity generated from an electrochemical cell.

The heat storage device can be used in a process to heat one or more components. The process may include the flow of a heat transfer fluid through the heat transfer device. The step for flowing a heat transfer fluid through the heat storage device may include flowing a heat transfer flow having an initial temperature through an inlet of the device; flowing the heat transfer fluid through an axial flow path so that the heat transfer fluid can be divided into a plurality of axial flow paths; flowing the heat transfer fluid through a radial flow path so that it can remove heat from the thermal energy storage material, where the thermal energy storage material has a temperature higher than the temperature initial heat transfer fluid; flowing heat transfer fluid through a different axial flow path so that a plurality of axial flow paths can be recombined; flowing the heat transfer fluid having an exit temperature through an outlet of the device, or any combination thereof. Preferably, the outlet temperature of the heat transfer fluid is greater than the initial temperature of the heat transfer fluid. The process for heating one or more components may employ a flow path through the heat storage device including one of a radial flow path selection and two axial flow paths, the flow path having a total flow length , where the total flow length is generally constant for the different axial flow trajectories.

The heat storage device and / or the heat storage system can be characterized as having a relatively high power (for example, as measured during the initial 30 or 60 seconds of heating) so that it can quickly heat a component, such as an internal combustion engine.

The heat storage device and / or the heat storage system may be characterized by an average power greater than about 5 watts, preferably greater than about 10 watts, more preferably greater than about 15 watts, and most preferably greater than about 20 watts. .

The heat storage device and / or the heat storage system can be characterized as having a relatively high power density, so that it can hold a large amount of thermal energy in a relatively small compartment. For example, the heat storage device and / or the heat storage system can be characterized as having a power density greater than about 4 kW / L, preferably greater than about 8 kW / L, more preferably greater than about 10 kW. / L and most preferably greater than about 12 kW / L.

The heat storage device and / or the heat storage system can be characterized as having a relatively low pressure drop of the heat transfer fluid (measured at a heat transfer fluid flow rate of approximately 10 L / min. ). For example, the heat storage device and / or the heat storage system may be characterized as having a pressure drop of the heat transfer fluid less than about 2.0 kPa, preferably less than about 1.5 kPa, more preferably less than about 1.2 kPa and most preferably less than about 1.0 kPa.

By way of example, the heat storage system may be employed in a transportation vehicle (eg, an automotive vehicle) to store energy from an engine exhaust gas. When the engine produces exhaust gas, a bypass valve can direct either the flow of the gas through the heat storage device such that the heat storage device is charged, or through a bypass line for charging. avoid overheating the heat storage device. When the engine is turned off, for example, during a period in which the vehicle is parked, a substantial portion of the heat stored in the heat storage device can be retained for a long time (for example, due to the vacuum insulation surrounding the device). of heat storage). Preferably, at least 50% of the thermal energy storage material in the heat storage device remains in a liquid state after the vehicle has been parked for 16 hours at an ambient temperature of about -40 ° C. If the vehicle is parked for a sufficiently long time (for example, at least two or three hours) for the engine to cool substantially (for example, in such a way that the difference in temperature between the engine and the environment is lower that approximately 20 ° C), the heat stored in the heat storage device can be discharged into the cold engine or other heat vessel indirectly by flowing a heat transfer fluid (such as engine coolant) through the heat exchanger thermal that includes the condenser for the operating fluid. The operating fluid circulates in a capillary pump circuit using the capillary structure inside the heat storage device where the operating fluid vaporizes. The heat from the operating fluid is transferred to the engine coolant in the heat exchanger. By employing the heat storage device, the heat that would otherwise be wasted may be captured during a previous activation in order to attenuate the cold start and / or provide instantaneous cabin heating.

The heat transfer using the operating fluid can begin by opening the operating fluid valve (ie, the discharge valve). The sealed reservoir of operating fluid connected to the circuit by an additional fluid line serves to adapt to changes in the volume of operating fluid within the circuit without substantial pressure changes. Once enough heat or all useful heat has been transferred from the heat storage device, the discharge valve can be closed. The operational fluid remaining in the heat storage device can be evaporated (for example, from the heat remaining in the heat storage device or when the heat storage device begins to charge) and then condensed in the condenser. As the heat storage device is evacuated from the operating fluid, the fluid level of the operating fluid level can be changed (e.g., increased).

Optionally, the heat storage device can be a transverse cross-flow heat exchanger (i.e., having a flow direction for the operating fluid and a perpendicular flow direction for the exhaust gas flow). For example, during operation, the heat storage device may include three chambers occupied by 1) exhaust gases; 2) stagnant phase change material (eg, inside capsules, such as a honeycomb); and 3) operative fluid. The three chambers are kept separated by thin walls made of an appropriate material, preferably stainless steel. Exhaust gases can flow between the surfaces (eg, curved surfaces) of the capsules of phase change material within the alveolar gaskets, and the operating fluid can flow between different surfaces (eg, flat surfaces) of the capsules of phase change material inside the alveolar gaskets in a direction that is generally perpendicular to the direction of flow of the exhaust gas. The liquid operating fluid that enters its chamber preferably moistens a capillary structure (eg, a metal wick) and is transported upwardly against the combined forces of gravity and vapor pressure by the capillary forces acting on the liquid meniscus of the fluid. Operating fluid formed inside the capillaries. This flow is sustained by the continuous evaporation of the liquid using the heat extracted from the phase change material inside the alveolar packages. Operating fluid vapor leaves the capillary structure and escapes towards the upper part of the device by means of steam channels which can be intertwined with columns of the capillary structure compressed between the surfaces (for example, the flat surfaces) of the capsules of phase change material inside the alveolar packages . The operating fluid vapor flows to the condenser where it transfers its heat of vaporization and sensible heat to the cold refrigerant and becomes liquid again to return to the heat storage device and continue its circulation in the circuit, being pumped only by the existing capillary forces within the capillary structure (for example, metal wick) that are partially impregnated by liquid operating fluid. All the columns of the capillary structure can be connected to a common porous base. Such a porous base can be used to distribute the liquid operating fluid that enters from the bottom of the device to the different columns.

In addition, the present invention can be used in combination with additional elements / components / steps. For example, the cooling system of the absorption cycle or admission for air conditioning can be used as the heat reservoir instead of or in addition to the cold refrigerant (for example, the condenser can also serve as an evaporator for the refrigerant that circulates inside a fluid circuit of the air conditioner). In another application, a stationary residual heat recovery system that uses μ? thermal engine, for example, a Rankine cycle, can be built to use the same fluid operating a capillary pumping circuit or a different one and adding a mechanical power generation turbine to the steam pipe between the heat storage device and the condenser, (for example, exceeding the high vapor pressure upstream of the turbine) , and / or add a liquid pump to the liquid line between the condenser and the heat storage device. The aforementioned turbine can convert a part of the residual heat of the captured exhaust gas into useful mechanical or electrical work and, consequently, improve the overall fuel efficiency of the vehicle.

EXAM PLOS Example 1 is an article that includes 7 sealed spaces containing thermal energy storage material and suitable for heat storage. The packages are formed by filling a base sheet that has 7 hoppers with a thermal energy storage material. Each hopper is capable of housing approximately 7 cm3 of liquid. The base sheet is covered with a flat cover sheet. The base sheet and the cover sheet are made of 304 stainless steel and have a thickness of about 0.12 mm. The thermal energy storage material is a metal salt and has a melting temperature of about 1 95 ° C. The thermal energy storage material is anhydrous or has a moisture concentration of about 0.01% by weight or less. The two sheets come together while the material of Storage of thermal energy is in solid state (approximately 23 ° C). A major seal is provided by laser welding the base sheet and the cover sheet around the periphery of each sealed space. When heated to a temperature of approximately 250 ° C, the seal has an internal pressure of approximately 69 kPa (approximately 1 0 psi).

Cyclic thermal test Approximately 10 items from Example 1 are stacked and placed in a container that has an entrance and an exit. The inlet is connected to a hot tank of a heat transfer fluid at a temperature of about 250 ° C and a cold tank of a heat transfer fluid at a temperature of about 15 ° C. The heat transfer fluid is allowed to flow through the vessel until the temperature of the thermal energy storage material is about 240 ° C, then the latent heat transfer fluid is allowed to flow through the vessel to than the temperature of the thermal energy storage material from about 25 ° C. The temperature of the thermal energy storage material is recycled approximately every 5 m inutes for approximately 1, 000 cycles.

One or more sealed spaces of Example 1 break and / or develop a leak in the main seal during the thermal cyclic test before reaching 1, 000 cycles. The thermal energy storage material is filtered from one or more sealed spaces and Example 1 does not pass the thermal cyclic test.

Hot test An article of Example 1 is placed in an oven at a temperature of about 400 ° C for about 30 minutes. Then, the article is evaluated to determine if there are leaks or ruptures that would allow the thermal energy storage material to seep out of the article. One or more leaks and / or ruptures are observed and Example 1 does not pass the hot test.

Example 2 is an article that includes 7 sealed spaces prepared using the method of Example 1, except that a secondary seal is prepared by laser welding the base sheet and the cover sheet near its outer peripheries and near its peripheries of opening. The articles are tested using the same method as that described for Example 1. The maximum voltage of von Mises is above the yield stress of the sheet. During thermal cycling, the main seal expires around one or more sealed spaces. The secondary seal does not expire after 1, 000 thermal cycles and the thermal energy storage material does not leak from the article.

Another article of Example 2 is tested by heating to 400 ° C. At 400 ° C, one or more major seals expire. However, the secondary seal does not expire and the thermal energy storage material does not leak.

Example 3 is an article that includes 7 sealed spaces prepared using the method of Example 1, except that both the base sheet and the cover sheet use sheets having a thickness of about 0.204 mm. The articles are tested using the same method as that written in Example 1. The maximum voltage of von Mises lies below the yield stress of the sheet. The main seal does not expire after 1, 000 thermal cycles and the thermal energy storage material does not leak from the article.

Another article of Example 3 is tested by heating to 400 ° C during 20 minutes. At 400 ° C, none of the seals expires and the thermal energy storage material does not leak.

Example 4 is an article that includes 7 sealed spaces prepared using the method of Example 1, except that the cover sheet uses a sheet having a thickness of about 0.204 mm. The articles are tested using the same method as that described for Example 1. The maximum von Mises stress is reduced by approximately 1 80 MPa, below the yield stress of the sheet. The main seal does not expire after 1, 000 thermal cycles and the thermal energy storage material does not leak from the article.

Another article of Example 4 is tested by heating at 400 ° C for 20 minutes. At 400 ° C, none of the seals expires and the thermal energy storage material does not leak.

Example 5 is an article including 7 sealed spaces prepared using the method of Example 1, except that the cover sheet is stamped so that the cover sheet on each sealed space housing the thermal energy storage material is approximately 1 5 rods include both notches and protrusions each having a depth of 0. 1 to 0.5 mm. The articles are tested using the same method as that described for Example 1. The maximum von Mises stress is approximately 233 MPa, less than the yield stress of the sheet. The main seal does not expire after 1, 000 thermal cycles and the thermal energy storage material does not leak from the article. It will be appreciated that one, two or more rods may be employed and that the rods may be notches, protrusions or both.

Another article of Example 5 is tested by heating at 400 ° C for 20 minutes. At 400 ° C, none of the seals expires and the thermal energy storage material does not leak.

Example 6 is an article that includes 7 sealed spaces prepared using the method of Example 1, except that the cover sheet is treated such that a sealed space that includes the thermal energy storage material has approximately 34 depressions that are embedded approximately 0.6 nm in the sealed space. The depressions in the cover sheet are in a brick wall pattern as shown schematically in Figure 4B. The articles are tested using the same method as that described for Example 1. The maximum von Mises stress is approximately 590 MPa and is greater than the yield stress of the sheet. The main seal is expired during thermal cycling and the thermal energy storage material leaks from the article. It will be noted that more or less depressions may be employed and that these may be deeper or more superficial.

Another article of Example 6 is tested by heating to 400 ° C during 20 minutes. At 400 ° C, the seals are expired and the thermal energy storage material leaks.

Example 7 is an article that includes 7 sealed spaces prepared using the method of Example 6, except that the cover sheet is made of a sheet having a thickness of about 0.1 53 mm. The articles are tested using the same method as that described in Example 1. The maximum von Mises stress is approximately 282 MPa and is lower than the yield stress of the sheet. The main seal does not expire during thermal cycling and the thermal energy storage material does not leak from the article after 1, 000 thermal cycles.

Another article of Example 7 is tested by heating at 400 ° C for 20 minutes. At 400 ° C, the seals do not expire and the thermal energy storage material does not leak.

Example 8 is an article that includes 7 sealed spaces prepared using the method of Example 1, except that the cover sheet is stamped with a plurality of chevrons including slots and projections of approximately 0.5 mm. The chevrons in the cover sheet have a repeating pattern as seen schematically in Figure 4A. The articles are tested using the same method as that described for Example 1. The maximum von Mises stress is approximately 600 Mpa and is greater than the yield stress of the sheet.

Example 9 is an article that includes 7 sealed spaces prepared using the method of Example 1, except that a vacuum of about 200 Torr is applied when the cover sheet and the base sheet are welded together. When the thermal energy storage element is at a temperature of about 25 ° C, the pressure in the sealed space is less than about 400 Torr. The articles are tested using the same method as that described for Example 1. The maximum von Mises stress is less than the yield stress of the sheet. The main seal does not expire during thermal cycling and the thermal energy storage material does not leak from the article after 1, 000 thermal cycles.

Another article of Example 9 is tested by heating at 400 ° C for 20 minutes. At 400 ° C, the seals expire and the thermal energy storage material escapes.

Example 10 is an article that includes 7 sealed spaces prepared using the method of Example 1, except that the cover sheet and the base sheet are jointly welded when the thermal energy storage material is at a temperature of about 250. ° C. When the thermal energy storage material is at a temperature of about 25 ° C, the pressure in the sealed space is less than about 400 Torr. The articles are tested using the same method as that described for Example 1. The maximum von Mises stress is less than the yield stress of the sheet. The main seal does not expire during the thermal cycle and the thermal energy storage material does not leak out of the article after 1, 000 thermal cycles.

The article of Example 10 is tested by heating at 400 ° C for 20 minutes. At 400 ° C, the seals are expired and the thermal energy storage material leaks.

The preferred embodiment of the present invention has been described.

However, the person skilled in the art observes that some modifications come within the teachings of this invention. Therefore, the following claims should be studied to determine the true scope and content of the invention.

Any numerical values cited in the previous application include all the values derived from the value less than l greater value in increments of one unit since there is a separation of at least 2 units between any lower value and any higher value. By way of example, it is stated that the amount of a component with a value of a variable process such as, for example, temperature, pressure, time and the like is, for example, ranges from 1 to 90, preferably from 20 to 80. , more preferably from 30 to 70, it is intended that values such as 1 5 to 85, 22 to 68, 43 to 51, 30 to 32 etc. are specifically numbered in this specification. For values that are less than one, a unit is considered to be 0 0001, 0.001, 0.01 or 0.1 as appropriate. These are only examples of what is specifically intended and all possible combinations of numerical values between the lowest value and the highest value numbered as expressly stated in this application should be considered in a similar manner. Unless declared otherwise, all intervals include both endpoints and all numbers between the endpoints. The use of "about" or "approximately" in relation to a range applies to both ends of the interval. Consequently, "approximately 20 to 30" is intended to cover "approximately 20 to approximately 30", inclusive of at least the specified endpoints. The parts by weight as used herein refer to compositions containing 1 00 parts by weight. Descriptions of all articles and references, including patent applications and publication, are incorporated by reference for all purposes. The term "consisting essentially of" to describe a combination shall include the elements, ingredients, components or steps identified, and such other elements, ingredients, components or steps that do not materially affect the basic and novel characteristics of the combination. The use of the terms "comprising" or "including" to describe combinations of elements, ingredients, components or steps herein also considers the modalities consisting essentially of the elements, ingredients, components or steps. The elements, ingredients, components or plural steps can be provided by a single element, ingredient, component or integrated step. Alternatively, a single element, ingredient, component or integrated step could be divided into plural and separate elements, ingredients, components or steps. The description of "a" or "an" to describe an element, ingredient, component or step does not intend to execute additional elements, ingredients, components or steps.

Claims (20)

1. REIVI N DI CAC ION ES 1 . An article that includes: a common metal foil; a metal cover sheet, wherein the metal base sheet and the metal cover sheet are hermetically joined to form one or more sealed spaces; a thermal energy storage material, where the thermal energy storage material is housed within the sealed spaces; where the sealed spaces practically lack water or include liquid water at a concentration of approximately 1% by volume or less at a temperature of approximately 25 ° C, based on the total volume of the sealed spaces; Y where the article includes one or more of the following elements: a. the pressure in a sealed space is about 700 Torr or less, when the temperature of the thermal energy storage material is about 25 ° C; b. the metal cover sheet includes one or more reinforcement elements, wherein the reinforcement elements include notches within the sealed space, protrusions outside the sealed space or both, which are sufficient in size and number to reduce the maximum stress of von Mises in the cover sheet during thermal cycling; c. the metal cover sheet and / or the metal base sheet includes one or more volume expansion elements; or d. the metal cover sheet has a thickness, tc, and the metal base sheet has a thickness, tb, where tc is greater than tb such that the article does not leak after thermal cycling between about 25 ° C and about 240 ° C, for 1,000 cycles. 2. The article according to claim 1, wherein the pressure in a sealed space is a vacuum of about 600 Torr or less, at a temperature of about 25 ° C. 3. The article according to claim 1 or 2, wherein the article is prepared by a process including a step for joining the metal base sheet and the metal cover sheet when the thermal energy storage material is at a binding temperature (T i) of at least the melting temperature of the thermal energy storage material (TL.TESM) - 4. The article according to any of claims 1 to 3, wherein i) the ratio of the thickness of the metal cover sheet to the thickness of the metal base sheet, tc / tb, is about 1.05 or more; ii) the difference between the thickness of the metal cover sheet and the thickness of the metal base sheet, tc-tb, is approximately 0.02 mm or more, or iii) both i) and ii). 5. The article according to any of claims 1 to 4, wherein the article includes one or more welds joining the metal cover sheet and the metal base sheet, wherein said one or more welds fully include the sealed spaces; he. The article has an opening near the center of the article so that a heat transfer fluid can flow through the opening; and the article is sealed around a periphery of the opening, so that the heat transfer fluid is not in contact with the thermal energy storage material in the sealed space. 6. The article according to any of claims 1 to 5, wherein the metal cover sheet includes one or more reinforcement elements. 7. The article according to any of claims 1 to 6, wherein the metal cover sheet, the metal base sheet, or both, includes one or more volume expansion elements. 8. The article according to claim 7, wherein said one or more expansion volume elements include depressions, chevrons, wrinkles, bends, convolutions or any combination thereof. 9. The article according to any of claims 1 to 8, wherein the metal cover sheet is stamped so that the von Mises tension of the article at a temperature of about 250 ° C is reduced by about 10% or more in comparison with an article in which the metal cover sheet is generally flat. 10. The article according to any of claims 1 to 9, wherein the von Mises stress on both the metal base sheet and the metal cover sheet due to the thermal expansion of the thermal energy storage material during repeated thermal cycling between about 30 ° C and about 250 ° C is less than the yield stress of the metal of the cover sheet. eleven . The article according to any one of claims 1 to 10, wherein the sealed spaces of the article do not have any after heating at about 400 ° C for about 4 hours. 12. The article according to any of claims 1 to 11, wherein the thermal energy storage material has a melting temperature of about 25 ° C or more. 13. The article according to any of claims 1 to 12, wherein the thermal energy storage material has a melting temperature of about 150 ° C or more; and the thermal energy storage material is practically anhydrous. 14. A process for forming an article according to any of claims 1 to 13, wherein the metal base sheet includes one or more hoppers capable of housing a liquid, and the process comprises a step to at least partially fill one or more hoppers with the thermal energy storage material. 15. The process according to claim 14, wherein the thermal energy storage material is at a predetermined temperature which is at least the melting temperature of the thermal energy storage material when the base sheet and the cover sheet they are hermetically joined, so that when the article is cooled to approximately 25 ° C a vacuum is formed in the sealed space. 16. A process according to claim 14 or 15, wherein the step to hermetically join the base sheet and the cover sheet starts before the fill step of the tray with the thermal energy storage material and ends after the step of filling the hopper with the thermal energy storage material. The process according to any of claims 14 to 16, wherein the article is prepared by a process that includes a step for joining the metal base sheet and the metal cover sheet to form the sealed space, wherein the step connection includes a step to apply a vacuum to the region of the sealed space before joining the sheets. 18. A device that includes a stack of two or more articles according to any of claims 1 to 1 3. 19. The device according to claim 18, wherein each of the articles includes an opening and wherein the articles are configured so that the openings are generally aligned in an axial direction, and the article stack is housed in an insulated container. . 20. A process for storing heat comprising a step for: transferring a sufficient amount of thermal energy to the article according to any of claims 1 to 15, so that the thermal energy storage material in the article is heated to a temperature of about 200 ° C or more. SUMMARY The present invention relates to articles 2 and heat storage devices 80 for the storage of thermal energy. The articles 2 include a metal base sheet 1 2 and a metal cover sheet 14, wherein the metal base sheet and the metal cover sheet are hermetically joined to form one or more sealed spaces 1 8. Items 2 include gn thermal energy storage material 1 6 which is housed within the sealed spaces 1 8. Preferably, the sealed spaces practically lack water or includes liquid water at a concentration of about 1% by volume or less at a temperature of about 25%. ° C, based on the total volume of the sealed spaces 1 8. The articles include one or more of the following characteristics: a) the pressure 36 in a sealed space is approximately 700 Torr or less, when the temperature of the material Thermal energy storage is approximately 25 ° C; b) the metal cover sheet 14 includes one or more stiffening elements 34, wherein the stiffening elements include notches within the sealed space, projections outside the sealed space, or both, which are sufficient in size and number to reduce the m maximum von Mises stress in the cover sheet during thermal cycling; c) the metal cover sheet 14 and / or the metal base sheet 1 2 includes one or more volume expansion elements 62; or d) the metal cover sheet has a thickness, tc, and the metal base sheet has a thickness, tb, where tc is greater than tb; in such a way that the article is durable. For example, the article does not have fygas after thermal cycling between about 25 ° C and about 240 ° C, for 100 cycles.