PCM CONTAINER APPROXIMATING A CONTAINER

Abstract

A phase change material container assembly for use in a thermal energy storage system. The container assembly includes a plurality of containers (plates, wedges . . . etc.) where the containers are generally flat and each approximating a segment of a ball or it may be a single device including features of a plurality of component containers as previously described. The components may be spherical segments, spherical wedges (ungula), hemispheres, spherical sectors, spherical caps or any combination. The plurality of containers are assembled to approximate a sphere's external perimeter. The plurality of containers are spaced apart to allow water, or other fluids, to flow between the plurality of containers.

Description

FIELD OF THE INVENTION

The present invention relates generally to containers for phase change materials. More particularly, this invention relates to a container or a group on containers for use with a thermal energy storage system for storing thermal energy.

BACKGROUND OF THE INVENTION

Phase change materials (PCMs) may be used in a thermal energy storage system (TESS) for storing thermal energy. In one approach, containers filled with PCM are disposed in a heat exchange fluid, such as water or air. The fluid, with or without the PCM containers, may be used in a system to absorb or release thermal energy. In one example, the PCM containers are spheres with an outer wall enclosing an interior volume filled with PCM. However, many PCMs have poor thermal conductivity in one or more phases, so the maximum distance from the outer wall to any portion of the PCM should be limited to provide efficient transfer of thermal energy. It is known that PCMs in liquid and solid phases have differing thermal conductivities, and that liquid phase PCMs often have significantly poorer thermal conductivity than identical PCMs in their solid phases. If thermal energy is being added to PCM inside a container when it is solid, the PCM adjacent the outer wall will melt first, causing heat transfer to the remaining solid core to be exceptionally slower. The maximum acceptable distance from an outer wall to any portion of the PCM will depend on the characteristics and performance requirements of a TESS.

SUMMARY OF THE INVENTION

The present invention relates to a phase change material container assembly for use in a thermal energy storage system. The container assembly may include a plurality of containers where the containers are generally flat and each approximating a segment of a ball (also referred to as sphere—in the present disclosure, the terms are used interchangeably), or it may be a single device including features of a plurality of component containers as previously described. The components may be spherical segments, spherical wedges (ungula), hemispheres, spherical sectors, spherical caps or any combination. The plurality of containers are assembled to approximate a sphere's external perimeter. The plurality of containers are spaced apart to allow water, or other fluids, to flow between the plurality of containers.

The plurality of containers are each filled with a thermal energy material (by way of example, a PCM) thereby permitting absorption and release of thermal energy. A connecting member, central core interlocking feature on each container, or another device or other device is provided connecting the plurality of containers. The connecting member may be any connector, fastener, cam, adhesive or other member capable of connecting the plurality con containers together.

The central core or device may include a ballast to assist in making the container have a different buoyancy. Alternately, ballast may be added to each container by installing a material with greater or lesser specific gravity which may enable the container to become positively, negatively, or neutrally buoyant with respect to the fluid in which it is intended to be placed or contained (i.e. sand). Further, a mechanical ballast may be added to each container separately, either container therein or thereon. Anti-ballast is defined as an antonym for ballast. In the present invention, a “ballast” (or “anti-ballast”) may be true ballast (heavier) or anti-ballast (lighter.) The anti-ballast could be air, nitrogen, helium . . . etc. A further example would be installing a quantity of sand, with a specific gravity greater than the PCM and greater than the water in a TESS tank in an amount measured to offset the difference between the containers together with the contents and the working fluid in which they are placed, thereby creating neutral buoyancy. A plurality of bumps or protrusions space apart the containers creating a space between each container, further enhancing surface area, and improving structural rigidity.

The individual containers comprising the plurality may be replaceably removable to affect the PCM mass of the device and therefore modifying its performance characteristics. The containers may be replaced with alternates containing a PCM with a different phase change temperature than the ones being replaced.

Other non-spherical shapes may be used as PCM containers all of which exhibit greater surface area to volume ratio. However, a generally spherical shape provides other benefits. For example, spheres pack efficiently into a container, will flow through pipes, and may be easier to handle such as when dumping a large number of containers into a TESS tank. Spheres when randomly packed exhibit a formation that is mostly symmetrical and provides for minimal contact between spheres and permits even flow of the fluid through a 2 or 3 dimensional array of them in a container. This alone makes spheres advantageous in systems that include the flow of working fluid intended to contact as much surface area as possible of the included containers.

Other shapes such as any shape from the group including uniform polyhedra, (Platonic, Archimedian, Kepler-Poinsot), Johnson solids, Catalan solids, regular polyhedra, abstract polyhedra, prisms, antiprisms, cylindrical solids, annular rings, or any other shape having a surface which may be reasonably approximated in the construction of a container may be substituted for the example of spheres and may benefit from the enhancement of surface area as described in the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an embodiment of the thermal energy material (or PCM) container assembly having a plurality of generally flat spherical segment layers forming the container assembly;

FIG. 2 illustrates a cross-sectional view of the PCM container assembly as illustrated in FIG. 1;

FIG. 3 illustrates a perspective view of the PCM container assembly;

FIG. 4 illustrates a cross-sectional view of the PCM container assembly illustrating the ballast;

FIG. 5 illustrates an exploded perspective view of the plurality of containers used to assemble the full PCM container assembly;

FIG. 6 illustrates a cross-sectional view of a first portion of the core for holding the plurality of PCM containers together;

FIG. 7 illustrates a second portion of the core operable to hold the plurality of PCM containers together;

FIG. 8 illustrates a perspective view of an alternative vertical fin plate embodiment;

FIG. 9 illustrates a side view of an alternative vertical fin plate embodiment;

FIG. 10 illustrates a partially exploded perspective view of an alternative vertical fin plate embodiment;

FIG. 11 illustrates a perspective partially exploded view of an alternative wedge embodiment;

FIG. 12 illustrates a top view of wedge of an alternative wedge embodiment assembly;

FIG. 13 illustrates a perspective partially exploded view of a second alternative wedge embodiment;

FIG. 14 illustrates an assembly perspective view of the second alternative embodiment;

FIG. 15 illustrates an assembled perspective view of a third alternative wedge embodiment;

FIG. 16 illustrates an partially exploded and assembled perspective view of a third alternative wedge embodiment;

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides a larger thermal energy material (i.e. phase change material, hereinafter referred to as ‘PCM’) container assembly that approximates a sphere's external perimeter in three dimensions.

It should be noted that this description continuously refers to a general thermal energy material as a PCM. In this specification, the terms PCM and thermal energy material may be used interchangeably. Thermal energy material is defined as any material that can store or move energy, such as a PCM. The thermal energy material may also be referred to as a heat transfer fluid. Referring to FIG. 1, an exemplary container assembly in accordance with one embodiment of the present invention is shown at 10. FIG. 2 shows a cross sectional view. The container assembly 10 is composed of a plurality of generally flat containers that each approximate a segment of a sphere, geometrically described as a spherical segment. A spherical segment is the solid defined by cutting a sphere with a pair of parallel planes. It corresponds to a spherical frustum. One container is indicated at 12. As shown, this container 12 has a generally flat upper surface 14 and a general flat lower surface 16. In a top view, these surfaces would each be somewhat disk shaped. The upper and lower surfaces are interconnected by a generally annular outer edge 18.

An adjacent container is indicated at 20. The containers 12 and 20 are spaced apart by a short distance. In one example, each container 12 and 20 has a height of approximately 0.1-20 mm mm, such that all PCM in the container is within 0.1-20 mm of an outer wall. The gaps between containers may be in the range of 0.1-20 mm, in one example. In other embodiments, the percentage of diameter may be much smaller thus providing for very small gaps or very large gaps. A plurality of the containers, each approximating a segment of a sphere, are stacked with spherical segment spaces between each container. The resulting assembly has an outer surface that approximates a sphere. In the illustrated embodiment, the containers are interconnected by a central core 22, which defines a “pole” of the sphere. Each of the containers may be a separate container with the plurality of containers then joined together and each container is individually filled with PCM, before or after joining. Alternatively, the container assembly may be produced as a larger piece with the individual containers being just a portion of the overall piece, and some or all of the larger container assembly may be filled in one step.

In one example, it is desirable that this distance be between 0.1-20 mm. This is largely due to the fact that most TES systems work on a diurnal cycle and therefore a limited time for storage and discharge is available. It is also true that many TESS in need of retrofit with a latent heat storage solution were originally designed to operate using sensible heat. These systems typically have water temperature adjusting equipment (such as chillers or boilers) which by design can only generate a very small ΔT (difference in temperature) and therefore do not have sufficient time to generate enough energy to penetrate large thicknesses of PCM to melt or solidify the PCM.

As such, small containers would need to be limited to approximately 0.1-20 mm (as shown in FIG. 4 at reference X) in diameter if all PCM is to be within 0.1-20 mm of an outer wall. Such small spheres are difficult to make and to fill with PCM, and are therefore expensive. Making larger spheres reduces the difficulty and cost per volume of PCM, but increases the distance from an outer wall to the center of the PCM.

In the illustrated embodiment, each of the containers has bumps or raised areas 25 defined thereon. These bumps 25 help to maintain the spacing between the individual containers or to provide structural integrity to the assembly and/or inhibit flexing. The number and positioning of the bumps may be different than shown, or in some versions they may not be used. Alternatively, the individual containers may be spaced apart in other ways or may be interconnected by posts or tubes, with the tubes possibly providing a passage between connected containers.

In the illustrated embodiment, the outer edges 18 of each container are angled with respect to the pole such that each edge lies generally in the sphere being approximated. A zone is a surface of revolution about the z-axis, so the surface area is given by

S=2π∫x√{square root over (1+x′²)}dz.

In an alternative embodiment, the edges are perpendicular to the pole. The entire assembly would still approximate a sphere, but less precisely. In alternative embodiments discussed below, a spherical wedge is utilized encompassing the general formulas for volume and surface as enumerated below:

$V=\frac{\alpha }{2\pi }·\frac{4}{3}\pi r^3=\frac{2}{3}\alpha r^3$ $A=\frac{\alpha }{2\pi }·4\pi r^2=2\alpha r^2$

It may be desirable for a container 10 to be rotated to different orientations when fluid surrounding the container is flowing. The bumps 25 may be arranged so as to encourage such reorientation and such bumps may be wings, surfaces, or other features that promote symmetrical or asymmetrical movement of the overall system. It may also be desirable for the container assembly 10, when filled with PCM, to be neutrally buoyant with respect to the heat exchange fluid. Typically this will require adding a different density material, such as sand, metal or air, to the container assembly. In one version, the central core 22 may have metal, such as a metal ball or cylinder, disposed therein. This ball maybe restricted to an area close to the center of the container assembly such that it may be slightly off center, thereby changing the center of gravity. The ball may be free to move between two or more off center positions.

In a further version, the container assembly is formed as a helix, rather than a plurality of “segments”. This shape may help encourage reorientation.

The PCM container assembly 10 as illustrated in FIGS. 4-5 is an alternative embodiment slightly varied from the embodiment as illustrated in FIGS. 1-3. The assembly 10 includes a plurality of generally flat containers that each approximate a segment of a sphere, geometrically described as a spherical segment. A spherical segment is the solid defined by cutting a sphere with a pair of parallel planes. One container is indicated at 12. The plurality of containers 12 are stacked atop of one another to form and generally approximate a sphere.

Each of the containers 12 includes an alignment portions 28, 30. The first alignment portion 28 is a protrusion on a top surface of the container. The first alignment portion 28 corresponds to an indentation 30 in the bottom surface of the container. Further, the middle container includes two indentations 30.

The plurality of containers 12 are connected by means of a central core 22 formed by pieces 22a and 22b. The central core 22 extends at generally a center portion of each of the containers 12. Each of the containers 12 further include at least one bump or protrusion 23 thus allowing the containers 12 to be arranged in a spaced apart configuration. The containers must be in a spaced apart configuration to allow water or other fluids or liquids to flow between the containers 12. The containers may also have an internal reinforcement or post 24 for keeping the upper and lower surfaces parallel to each other, and avoiding bloat. The posts 24 may take a variety of forms.

It may also be desirable for the container assembly 10, when filled with PCM, to be neutrally buoyant with respect to the heat exchange fluid. The central core 22 includes a ballast 26 operable to move slightly within the core 22. The ballast 26 is provided to help maintain a neutral buoyancy of the assembly 10. The bumps 23 may be arranged so as to encourage such reorientation and such bumps may be wings, surfaces, or other features that promote symmetrical or asymmetrical movement of the overall system. In one version, the central core 22 may have metal, such as a metal ball or cylinder or ballast 26, disposed therein.

Referring to FIGS. 6 and 7, the central core may further be a 2-piece construction have a first portion 22a and a second portion 22b having various connection tabs to facilitate connection of the first portion and the second portion. The ballast may be enclosed in a spaced defined between the two core portions when they are joined. As shown, the space containing the ballast is larger than the ballast but located near the center of the overall assembly 10. This allows the ballast to shift from one off-center position to another as the assembly rotates, and to maintain the assembly in this new position until enough force again rotates it.

The embodiment as illustrated in FIGS. 1-10 may also be of a helix configuration, or similar structure.

In the embodiment as shown in FIGS. 4 and 5, the gaps between containers 12 may be in the range of 1-10 mm. The plurality of the containers 12, each approximating a segment of a sphere, are stacked with spherical segment spaces between each container. The resulting assembly has an outer surface that approximates a sphere. In the illustrated embodiment, the containers are interconnected by a central core 22, which defines a “pole” of the sphere. Each of the containers may be a separate container with the plurality of containers then joined together and each container is individually filled with PCM. Alternatively, the container assembly may be produced as a larger piece with the individual containers being just a portion of the overall piece, and some or all of the larger container assembly may be filled in one step.

FIGS. 8-10 illustrate an alternative embodiment assembly wherein the plates of the assembly float vertically (versus horizontally as in the embodiments described above).

A container assembly 110 includes a plurality of plates 112 or a plurality of generally flat containers that each approximate a segment of a sphere, geometrically described as a spherical segment. A spherical segment is the solid defined by cutting a sphere with a pair of parallel planes. One container is indicated at 112. The plurality of containers 112 are positioned side by side to form and generally approximate a sphere.

Each of the containers may be a separate container with the plurality of containers then joined together and each container is individually filled with PCM, before or after joining. Alternatively, the container assembly may be produced as a larger piece with the individual containers being just a portion of the overall piece, and some or all of the larger container assembly may be filled in one step.

The plurality of containers 112 are connected by means of a central core. The central core extends at generally a center portion of each of the containers 112. The containers must be in a spaced apart configuration to allow water or other fluids or liquids to flow between the containers 112. The containers may also have an internal reinforcement or post for keeping the upper and lower surfaces parallel to each other, and avoiding bloat. Alternatively, the container 112 may interconnect with each other without the need for a separate core element.

It may also be desirable for the container assembly 110, when filled with PCM, to be neutrally buoyant with respect to the heat exchange fluid. The container assembly 110 includes a ballast 114 operable to move slightly within the container assembly 110. The ballast 114 is provided to help maintain a neutral buoyancy (or to create a different buoyancy) of the container assembly 110.

The ballast 114 affects he five inner plates of the container 110. The container 110 utilizes a long pin through the center to assembly the plates 112 together. A keyed assembly allows the largest fill ports to be staggered to each other. The end plates are severely affected by the fill port scheme and may not be filled.

FIGS. 11 and 12 illustrate an alternative embodiment utilizing a plurality of wedge shaped container connected together to approximate a sphere. The container assembly 210 includes a plurality of wedges 230. Each of the containers may be a separate container with the plurality of containers then joined together and each container is individually filled with PCM, before or after joining. Alternatively, the container assembly may be produced as a larger piece with the individual containers being just a portion of the overall piece, and some or all of the larger container assembly may be filled in one step.

The plurality of containers 230 are connected by means of at central bore 236 forming a bore down the center of the sphere. A connecting member may be provided in the bore to hold the container together or the container of the assembly may interconnect or interlock without the need for a bore. The central core extends at generally a center portion at the end of each of the containers 230. The containers must be in a spaced apart configuration to allow water or other fluids or liquids to flow between the containers 230. The containers may also have an internal reinforcement or post for keeping the side surfaces parallel to each other, and avoiding bloat.

It may also be desirable for the container assembly 210, when filled with PCM, to be neutrally buoyant with respect to the heat exchange fluid. The container assembly 210 includes a ballast 214 operable to move slightly within the container assembly 210. The ballast 214 is provided to help maintain a neutral buoyancy (or to create a different buoyancy) of the container assembly 210.

Each of the wedges includes a side surface 240 having a plurality of generally rectangular shaped indentations 232. These indentations are provided to increase the surface area of the wedges 230. During use, water or other fluid can flow into and around these indentations to increase heat transfer between the PCM and the surrounding fluid. Accordingly, these indentations provide an advantage in that they improve heat transfer. The indentations may extend partially or entirely through the wedge 230.

The outer surface 234 includes an outer edge 238 which rests adjacent to the other outer edges when the container assembly 210 is assembled. The outer surface 234 further includes a plurality of interconnecting portion 250, 242.

In other embodiments, the indentations may be round, circular, square or any other suitable shape.

FIGS. 13 and 14 illustrate an alternative embodiment utilizing a plurality of wedge shaped containers connected together to approximate a sphere. The container assembly 310 includes a plurality of containers 330 shaped as wedges. Each of the containers 330 may be a separate container with the plurality of containers then joined together and each container is individually filled with PCM, before or after joining. Alternatively, the container assembly may be produced as a larger piece with the individual containers being just a portion of the overall piece, and some or all of the larger container assembly may be filled in one step.

The plurality of containers 330 are connected by means of at central bore 336 forming a bore down the center of the sphere. A connecting member may be provided in the bore to hold the container together or the container of the assembly may interconnect or interlock without the need for a bore. The central core extends at generally a center portion at the end of each of the containers 330. The containers must be in a spaced apart configuration to allow water or other fluids or liquids to flow between the containers 330.

The central core extends at generally a center portion of each of the containers 330. The containers may also have an internal reinforcement or post for keeping the upper and lower surfaces parallel to each other, and avoiding bloat.

It may also be desirable for the container assembly 310, when filled with PCM, to be neutrally buoyant with respect to the heat exchange fluid. The container assembly 310 includes a ballast 314 operable to move slightly within the container 310. The ballast 314 is provided to help maintain a neutral buoyancy (or to create a different buoyancy) of the assembly 310.

Each of the wedges includes a side surface 340 having a plurality of generally circular (or cone) shaped indentations 332. These indentations are provided to increase the surface area of the wedges 330. These indentations 332 may extend only partially or entirely through the wedge. During use, water or other fluid can flow into and around these indentations to increase heat transfer between the PCM and the surrounding fluid. Accordingly, these indentations provide an advantage in that they improve heat transfer.

Each of the wedges 330 includes an outer surface 334 having a protruding portion 346. The outer surface includes an outer edge 338 which rests adjacent to the other outer edges when the container assembly 310 is assembled.

Numerous other shapes and designs may also be utilized to provide for a container assembly operable to store PCM with increased and/or enhanced surface area and approximating any well-known shape. The shape could be any shape or Euclidian shape such as ovoid, rounded shapes, ellipsoidal, cubes, tetrahedrons . . . etc. Any real shape could be used in the present invention. In this disclosure, “shape” is defined as the quality of a distinct 3-dimensional object or body having an external surface.

A sphere or generally sphere-shaped container assembly is preferred for improved packing and flow reasons. The sphere or generally sphere-shaped container is advantageous in that the sphere shape allows a plurality of container assemblies (such as those discussed above) to roll on and against one another when submerged in a fluid during use.

The present invention may alternatively utilize any suitable shape by having a plurality of containers joined together to increase the surface area of the general shape and to approximate the outside surface of the shape. The design may also applied as an advanced heat exchanger.

It is further noted that the size of the containers or container assembly may be large ranging down to nano-scale. In a further embodiment, two or more of the containers may have a different PCM. Two or more PCMs would have different phase temperatures, thereby making one portion of the device useful for “ambient condition A” and the other portion useful for “ambient condition B” or “C” or equivalent. The “other PCM” which is the one which is not operating at a particular time would simply warm up or cool down consistent with the working fluid and not affect the operation of the PCM which is functioning a “at the time.”

FIGS. 15 and 16 illustrate an alternative embodiment utilizing a plurality of wedge shaped containers connected together to approximate a sphere. The container assembly 410 includes a plurality of containers 430 shaped as a wedges. Each of the containers 430 may be a separate container with the plurality of containers then joined together and each container is individually filled with PCM, before or after joining. Alternatively, the container assembly may be produced as a larger piece with the individual containers being just a portion of the overall piece, and some or all of the larger container assembly may be filled in one step.

The plurality of containers 430 are connected by means of at central bore 436 forming a bore down the center of the sphere. A connecting member may be provided in the bore to hold the container together or the container of the assembly may interconnect or interlock without the need for a bore.

The central bore extends at generally a center portion of each of the containers 430. The containers must be in a spaced apart configuration to allow water or other fluids or liquids to flow between the containers 430. The containers may also have an internal reinforcement or post for keeping the side surfaces surfaces parallel to each other, and avoiding bloat.

It may also be desirable for the container assembly 410, when filled with PCM, to be neutrally buoyant with respect to the heat exchange fluid. The container assembly 410 does not includes a dedicated ballast operable to move slightly within the container 410. Instead, the containers 430 are partially filled with sand which allow the containers 430 and the container assembly 410 to remain in a vertical orientation. The inclusion of sand mitigates the need for a ballast. Further, the send may help maintain a neutral buoyancy (or to create a different buoyancy) of the assembly 410. The sand acts as a natural ballast since it settles to the bottom of the wedge thus keeping the wedge in an upright and vertical position. Furthermore, the sand is conductive. Even further, the sand is compatible with the thermal energy material. Sand or other materials may be provided in a container or container assembly of any of the embodiments herein, for use as the only ballast or in combination with another ballast

In other embodiments, any material that has similar properties as sand and is compatible with the thermal energy material may be used within the containers.

The sand and PCM (or thermal energy material) may be filled through the fill ports 450, 452. The fill ports are positioned on the edge 460 of the wedge 430. The duel port filling system is advantageous in that it allows air to exit the container as the thermal energy material (i.e. PCM) or sand is entering the container.

Each of the wedges includes a side surface 440 having a plurality of generally rectangular shaped indentations 432. These indentations are provided to increase the surface area of the wedges 430. These indentations 432 may extend only partially or entirely through the wedge. During use, water or other liquid can flow into and around these indentations to increase heat transfer between the thermal energy material and the surrounding liquid. Accordingly, these indentations provide an advantage in that they improve heat transfer.

Each of the wedges 430 includes an outer surface 434. The outer surface includes an outer edge 438 which rests adjacent to the other outer edges when the container assembly 410 is assembled.

The invention is not restricted to the illustrative examples and embodiments described above. The embodiments are not intended as limitations on the scope of the invention. Methods, apparatus, compositions, and the like described herein are exemplary and not intended as limitations on the scope of the invention. Changes therein and other uses will occur to those skilled in the art. The scope of the invention is defined by the scope of the appended claims.

Claims

1. A container assembly for use in a thermal energy storage (TES) system, the container assembly comprising: at least one container, the containers each approximating a segment of a ball, the containers assembled to approximate a ball's external surface, the containers spaced apart to allow a fluid to flow between the containers; andthe containers each filled with a thermal energy material thereby permitting absorption and release of thermal energy.

2. The container assembly of claim 1 wherein a connecting portion is provided connecting the plurality of containers.

3. The container assembly of claim 1 wherein the container assembly includes a ballast or anti-ballast to assist in making the container have a different buoyancy.

4. The container assembly of claim 1 wherein at least some of the containers have one or more protrusions defined thereon to space apart the containers creating a space between each container and to control space between the containers.

5. The container assembly of claim 1 wherein the thermal energy material within the container assembly is spaced from an outer wall of the container within 0.1-20 millimeters.

6. The container assembly of claim 1 wherein the gaps between the containers are between 0.1-20 millimeters.

7. A container assembly for use in a thermal energy storage (TES) system, the container assembly comprising: at least one containers, the containers each approximating a portion of a shape, the containers assembled to approximate the shape's external surface, the containers spaced apart to allow a fluid to flow between the containers; andthe containers each filled with a thermal energy material thereby permitting absorption, storage and release of thermal energy.

8. The container assembly of claim 7 wherein the shape is one of a sphere, an ovoid, an ellipsoidal, a cube, a box or a tetrahedron.

9. The container assembly of claim 7 wherein a connecting portion is provided connecting the containers.

10. The container assembly of claim 7 wherein the container assembly includes a ballast to assist in making the container assembly have a neutral buoyancy or different buoyancy.

11. The container assembly of claim 7 wherein at least some of the containers have one or more surface features to control space between the adjacent containers.

12. The container assembly of claim 7 wherein the thermal energy material within the container is spaced from an outer wall of the container within 0.1-20 millimeters.

13. The container assembly of claim 7 wherein the gaps between the containers are between 0.1-20 millimeters.

14. The container assembly of claim 7 wherein a connector for attaching another of the various portions of a ball employs a snap ring.

15. The container assembly of claim 7 wherein the containers are individually removable to affect the thermal energy material mass of the device and therefore modifying its performance characteristics.

16. The container assembly of claim 7 wherein the containers are alternately filled with two or more different thermal energy materials.

17. The container assembly of claim 7 wherein the containers are each spherical wedges (ungula).

18. The container assembly of claim 7 wherein each of the containers includes at least one fill port.

19. The container assembly of claim 18 wherein two fill ports are provided.

20. The container assembly of claim 7 wherein a portion of sand is contained within the containers, the sand adapted to act as a ballast.