STORAGE

BACKGROUND

The present invention, in some embodiments thereof, relates to energy collection and, more specifically, but not exclusively, to methods and systems for solar energy collecting using integrated thermal energy storage.

Solar energy is a renewable source of energy that contributes less to global warming and related environmental problems than do fuel-based energy sources. In addition, in many cases solar energy is captured and used locally and thus reduces the need for transportation or importation of fuels such as fossil fuels.

Solar energy is captured, for example, by a collector that absorbs solar radiation and converts it to thermal energy, which then is used in a variety of applications. The conversion from solar energy to thermal energy occurs within a pipe, tube, or panel that comprises heat transfer fluid within the lumen of the pipe to transport the thermal energy generated from the collector to the application. As used herein, the term fluid channel means the portion of the solar radiation collector that is used for conversion of the solar radiation and transport of the heat transfer fluid, whether it be shaped as a pipe, tube, panel, and the like. Alternatively, solar radiation may be captured by a collector that absorbs solar radiation and converts a portion of it directly to electricity by photovoltaic methods, for example. Mirrors or lenses may be used to collect and concentrate solar radiation to be converted to heat or electricity by such methods.

Solar energy collectors have been designed and manufactured to numerous specifications. Many application areas require an economical source of energy for process heat or electricity generation, such as cleaning, laundry, sterilization, and the like. For example, U.S. Patent Application No. 13/696,811 describes devices, modules, and systems for solar energy collection and utilization, and is incorporated herein by reference in its entirety.

SUMMARY

According to some embodiments of the invention there is provided an energy receiving device for energy collection and storage. The energy receiving device comprises a fluid channel having therealong a solar radiation transparent section and a lumen, wherein the solar radiation transparent section is configured to receive solar radiation energy for a conversion to a thermal energy within the lumen and wherein the lumen is configured to allow flow of a thermal energy conducting fluid along the fluid channel. The energy receiving device comprises one or more heat storage components distributed along the fluid channel within the lumen, wherein the one or more heat storage component is in a thermal contact with the thermal energy conducting fluid. The one or more heat storage component is adapted to perform the conversion of the received solar radiation energy to the thermal energy. The one or more heat storage component is adapted to store the thermal energy. The one or more heat storage component is adapted to release the thermal energy to the thermal energy conducting fluid in the fluid channel. Inclusion of the one or more heat storage component in the fluid channel results in an increase in a total thermal energy capacity of the energy receiving device.

Optionally, the one or more heat storage component converts the solar radiation energy to the thermal energy.

Optionally, the total thermal energy capacity comprises a volumetric heat capacity of the one or more heat storage component.

Optionally, the one or more heat storage component is comprised of a solid shell and an inner heat storage material, wherein the solid shell surrounds the inner heat storage material, wherein the solid shell protects the inner heat storage material from degradation by the thermal energy conducting fluid, and wherein thermal energy flows between the thermal energy conducting fluid, the solid shell, and the inner heat storage material.

Optionally, the total thermal energy capacity further comprises a heat of melting of a phase change from a solid material state to a liquid material state of the inner heat storage material when the inner heat storage material changes phase during the storage and release of the thermal energy.

Optionally, the inner heat storage material comprises a thermo-chemical reaction material and during a chemical reaction of the thermo-chemical reaction material causes the storage and release of the thermal energy.

Optionally, the inner heat storage material is a mixture of two or more different inner heat storage material types. Optionally, the solid shell comprises a metal material.

Optionally, the one or more heat storage component is a single continuous element located in the lumen of the fluid channel.

Optionally, the one or more heat storage component is an array of heat storage components distributed along the lumen of the fluid channel.

Optionally, the one or more heat storage component comprises two or more heat exchange elements that increase the surface area of the heat storage component and increase a heat exchange rate between the one or more heat storage component and the thermal energy conducting fluid.

Optionally, the one or more heat storage component is distributed along a centerline of the lumen of the fluid channel, and wherein the thermal energy conducting fluid flows around the one or more heat storage component.

Optionally, the one or more heat storage component is distributed along a perimeter of the lumen of the fluid channel, and wherein the thermal energy conducting fluid flows inside the one or more heat storage component.

Optionally, the one or more heat storage component is distributed along at least part of the perimeter of the lumen of the fluid channel, and wherein the thermal energy conducting fluid flows along at least part of the one or more heat storage component.

Optionally, the one or more heat storage component replaces the solar radiation transparent section of the fluid channel.

Optionally, the fluid channel is a pipe.

Optionally, the fluid channel comprises a transparent material and the solar radiation transparent section comprises a complete circumference of the fluid channel.

Optionally, the fluid channel is a canister.

Optionally, the fluid channel is a flat structure, having one dimension substantially smaller than other dimensions.

Optionally, the fluid channel is a volumetric structure.

According to some embodiments of the invention there is provided a method for thermal energy collection and storage. The method comprises receiving a solar radiation from a solar radiation transparent section of a fluid channel. The method comprises converting the solar radiation to a thermal energy at the surface of one or more heat storage component located within the fluid channel. The method comprises storing the thermal energy to the one or more heat storage component in the fluid channel. The method comprises releasing the thermal energy from the one or more heat storage component to a thermal energy conducting fluid in the fluid channel. The one or more heat storage component is in thermal contact with the thermal energy conducting fluid, wherein the one or more heat storage component is distributed along the fluid channel, and wherein inclusion of the one or more heat storage component in the fluid channel results in an increase in total thermal energy capacity of an energy receiving device.

Unless otherwise defined, all technical and/or scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention pertains. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of embodiments of the invention, exemplary methods and/or materials are described below. In case of conflict, the patent specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and are not intended to be necessarily limiting.

Implementation of the method and/or system of embodiments of the invention may involve performing or completing selected tasks manually, automatically, or a combination thereof.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Some embodiments of the invention are herein described, by way of example only, with reference to the accompanying drawings. With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of embodiments of the invention. In this regard, the description taken with the drawings makes apparent to those skilled in the art how embodiments of the invention may be practiced.

In the drawings:

FIG. 1A is a schematic illustration of a cross section view of a fluid channel to collect solar energy and store thermal energy, according to some embodiments of the invention;

FIG. IB is a schematic illustration of an isometric view of a fluid channel to collect solar energy and store thermal energy, according to some embodiments of the invention; FIG. 1C is a schematic illustration of cross section view of a alternative fluid channel to collect solar energy and store thermal energy with heat storage components receiving solar radiation directly, according to some embodiments of the invention;

FIG. 2 is a flowchart of a method to collect solar energy and store thermal energy, according to some embodiments of the invention;

FIG. 3 is a graph of solar energy collection and thermal energy output during fluid channel operation, according to some embodiments of the invention;

FIG. 4 is a table of example of example phase change materials for thermal energy storage, according to some embodiments of the invention; and

FIG. 5 is a graph of heat storage capacities versus reaction temperatures for phase change materials, thermo-chemical materials, and water, according to some embodiments of the invention.

DETAILED DESCRIPTION

The present invention, in some embodiments thereof, relates to energy collecting and, more specifically, but not exclusively, to solar energy collecting and integrated thermal energy storage.

Systems for conversion of solar energy to thermal energy are typically designed for to produce thermal energy based on the application's requirements. When the solar energy is temporarily unavailable, such as when clouds and/or overcast block the solar radiation from reaching the solar energy collectors, a backup energy system is used to produce thermal energy. The backup energy systems typically operate on fossil fuels or electricity, increasing the total system cost and/or dependency on non-renewable resources. Alternative backup solutions include thermal energy storage in ground water or separate thermal energy storage systems. A separate thermal storage system and/or backup system are both expensive, require a large space for locating the backup system(s), consume power, such as for pumps, and require operating and/or maintenances resources. By integrating the thermal storage into the solar collecting system itself, the system costs, space needed, and maintenance costs are reduced relative to backup systems and/or separate thermal storage systems.

According to some embodiments of the present invention, there are provided a device and a method to transport thermal energy to an application, using elongated heat storage components are mounted along the lumen of the fluid channel. The elongated heat storage components provide thermal energy when the solar radiation reaching the collectors is limited, such as in the case of clouds above the solar collectors. Elongated heat storage components are mounted in the lumen of the fluid channels in parallel to the longitudinal axis of the lumen. The solar radiation energy enters the fluid channel through a solar radiation transparent portion of the tube and/or pipe where the solar energy is converted to thermal energy at the surface of a radiation absorber element. The radiation absorber element is a surface of the pipe, lumen, or heat storage components that converts the solar radiation to thermal energy, such as a black paint coated surface and/or selective coating. The transparent portion is along the length of the fluid channel, such as a transparent material fluid channel, a transparent window along the fluid channel, an aperture, and the like. The thermal energy causes the temperature of the heat transfer fluid to increase, and the fluid is transported to a location where the thermal energy and/or heat transfer fluid is used by the application. The elongated heat storage components may be a continuous elongated heat storage component mounted along the lumen of the fluid channel, an array of components distributed along the lumen, an array of continuous component segments, and the like. The elongated heat storage components form an integral part of the total heat storage capacity of the system, and allow the system to continue to supply thermal energy to the application when the solar radiation is not reaching the fluid channel. For example, the solar radiation is blocked by clouds for a short period of time, such as in the range of minutes up to an hour, and during that time the thermal energy is transferred from the elongated heat storage components to the heat transfer fluid so that thermal energy is continuously supplied to an application.

The elongated heat storage components may comprise a single material element or a composite of several materials, such as an outer solid shell and heat storage material. The materials for the elongated heat storage components are chosen so that the heat storage capacity per unit volume is greater than the heat transfer fluid volumetric heat capacity, thereby increasing the total heat storage capacity. The component's heat storage capacity may be comprised of the volumetric heat capacity of the heat storage material and/or shell material (sensible heat portion), heat of melting a phase change material, heat of reaction of a thermo-chemical material, and the like. The inclusion of the elongated heat storage components in the fluid channel is maintenance free, allows a reduced investment in a separate thermal energy storage system and/or backup thermal energy production system, and reduces heat loss of storage elements and/or storage system.

Optionally, the elongated heat storage components comprise an outer shell surrounding a heat storage material, where the heat storage material undergoes a solid to liquid phase change to absorb additional thermal energy by conversion of the thermal energy to heat of melting. For example, a salt is used as a heat storage material and the salt absorbs additional thermal energy when changing to a liquid phase. The heat of melting in many materials is larger than the volumetric heat capacity and the melting process is performed in a constant temperature or small temperature range. For example, the heat storage material is Galactitol and the temperature of melting is in the range of 180 to 190 degrees centigrade. For example, the heat storage material is a nitrate salt and the temperature of melting is from 210 to 240 degrees centigrade. Using a phase change material encapsulated along the fluid channel increases the heat storage capacity of the fluid channel and allowing a longer time without solar radiation energy input while keeping an output application temperature within a working range.

Optionally, the heat storage material undergoes a chemical reaction, such as a chemical reaction of FeC03 <-> FeO+C02, that uses thermal energy as part of the thermodynamic enthalpy of the reaction, such as the heat of reaction.

Optionally, the outer surface of the elongated heat storage components and/or the outer shell of the elongated heat storage components have a shape that increases surface area and thereby increases the thermal heat transfer rate between the elongated heat storage components and the heat transport fluid. For example, the outer surface has heat exchange fins. For example, the outer surface has a star shaped cross section.

Optionally, the outer surface of the elongated heat storage components and/or the outer shell of the elongated heat storage components have a coating that increases the thermal heat transfer rate between the elongated heat storage components and the heat transport fluid.

Before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not necessarily limited in its application to the details of construction and the arrangement of the components and/or methods set forth in the following description and/or illustrated in the drawings and/or the Examples. The invention is capable of other embodiments or of being practiced or carried out in various ways.

The present invention may be a system, an apparatus, a device, a process and/or a method.

Aspects of the present invention are described herein with reference to flowchart illustrations and/or block diagrams of methods, apparatus, and systems according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer readable program instructions.

The flowchart and block diagrams in the Figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and devices according to various embodiments of the present invention. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of instructions, which comprises one or more actions for implementing the specified logical function(s). In some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems that perform the specified functions or acts or carry out combinations of special purpose hardware and computer instructions.

Reference is now made to FIG. 1A, FIG. IB, and FIG. 1C which are schematic illustrations of views of fluid channels 100 to collect solar energy and store thermal energy, according to some embodiments of the invention. The fluid channel comprises a lumen 104 of a pipe and/or plate 108 containing heat transfer fluid and elongated heat storage components, as at 106 and 107. The elongated heat storage components comprise an outer shell 107 containing a heat storage material 106. Solar radiation energy 102 enters the lumen 104 of a fluid channel 100 through a transparent section 105 of the fluid channel 100. Optionally, a lens 101 may concentrate solar radiation energy towards the fluid channel. The outer shell 107 contains a thermal energy storage material 106 for storing thermal energy during a charging state of the system and releasing the thermal energy during a discharging state of the system when solar radiation energy is not available, such as when a cloud obscures the fluid channel or at the end of the day. The thermal energy storage material 106 may be a phase change material that is converted from a solid phase to a liquid phase when thermal energy is received. The outer shell 107 may contain a chemical reaction material as the heat storage material 106, where the chemical reaction proceeds in the endothermic direction when thermal energy is received and in the exothermic direction when thermal energy is discharged.

Optionally, the fluid channel is surrounded by a thermal isolation layer 103 to prevent loss of thermal energy from the fluid channel 100 that has a high thermal resistance, such as a ceramic coating and/or vacuum canister layer.

Optionally, the pipe and/or plate 108 are comprised of a solar radiation transparent material and the transparent section 105 is the complete pipe and/or plate 108 containing the heat transfer fluid.

Optionally, the position of the heat transfer fluid is in the lumen of the outer shell 107 and the thermal energy storage material 106 is in the lumen of the fluid channel 104, such that their positions are switched.

Optionally, the outer shell 107 is flush with and/or replaces the radiation transparent section 105. Referring again to FIG. 1C, the illustration shows the case when the outer shell 107 is flush with and/or replaces the radiation transparent section 105, such that the outer shell serves as a surface to convert solar radiation energy to thermal energy. The thermal energy is transferred to the thermal energy storage material

106 and heat transfer fluid from contact with the outer shell 107.

Reference is now made to FIG. 2, which is a flowchart of a method to collect solar energy and store thermal energy, according to some embodiments of the invention. Upon starting 200 the method execution, solar radiation energy is received 201 through a transparent section 105 of the fluid channel 100, and converted to thermal energy, for example at the surface of the outer shell 107 of an elongated heat storage component. Via the outer shell 107, the thermal energy is received as at 202B and 202 A by the heat transfer fluid and by the heat storage material 106 respectively. The thermal energy causes an increase in temperature of the heat transfer fluid in the lumen 104 and/or heat storage material 106 during a charging state of the fluid channel 100. When the heat storage material 106 temperature is the same as the outer shell 107 and heat transfer fluid, the fluid channel with the elongated storage elements enclosed is in the fully charged state. When there is no longer solar radiation energy received by the fluid channel, the elongated heat storage components in the lumen 104 release 203 the stored thermal energy to the heat transfer fluid for use 204 by the application, in a discharge state, the method actions end 299. For example, when solar radiation is interrupted from entering the fluid channel for up to one hour the thermal energy for the application's use is discharged 203 from the heat storage components to the heat transfer fluid.

Reference is now made to FIG. 3, which is a graph 300 of solar energy collection and thermal energy output during fluid channel operation, according to some embodiments of the invention. The incident solar radiation received 301 by the fluid channel 100 through the transparent section 105 is converted to thermal energy 302, for example, at the surface of an elongated heat storage component 107. The elongated heat storage components 106 store the thermal energy 303 at the beginning of the day during a charging state, and when the solar radiation energy is obstructed, such as temporarily by clouds 304 or at the end of the day 305, the elongated heat storage components 106 of the fluid channel transfer thermal energy to the heat transfer fluid in a discharging state. When during receipt of solar radiation the temperatures of the heat transfer fluid and elongated heat storage components are identical the system is at steady state and the heat storage fully charged. This state may be termed the fully charged state.

The example of FIG. 3 illustrates the benefits of the integrated thermal storage 106 when the solar radiation energy 102 is interrupted. During interruption in the solar radiation energy available, heat is automatically released from the integrated thermal storage 106 to the heat transfer fluid. This process occurs automatically due to the temperature changes of the heat transfer fluid when the solar radiation energy is received or interrupted. For example, when the fluid channel 100 starts receiving solar radiation, the temperature of the heat transfer fluid occupying the lumen 104 begins to rise, and the temperature of the elongated heat storage components, as at 106 and 107, also begin to rise. When the solar radiation energy received by the fluid channel 100 is obstructed, the heat transfer fluid stops receiving the converted solar energy and the temperature of the fluid begins to decrease due to the application's use of the available thermal energy in the heat transfer fluid. The elongated heat storage components, as at 106 and 107, automatically begin to transfer heat to the fluid since the elongated heat storage components is at a higher temperature than the heat transfer fluid. Once the solar radiation energy into the fluid channel 100 is restored, the heat transfer fluid and elongated heat storage components, as at 106 and 107, begin receiving heat and their temperatures again rise to the steady-state operational temperature. At the end of the day, the temperature of the fluid drops again, and the heat is transferred from the elongated heat storage components, as at 106 and 107, until the temperatures of both the fluid and elongated heat storage components are below the minimum application temperature threshold. Thus, the elongated heat storage components, as at 106 and 107, acts as a buffer to allow heat transfer to the application during interruption of the received solar radiation energy.

The following paragraphs provide details and examples of various options of the elongated heat storage components.

Optionally, the thermal energy storage material 106 is a sensible-type thermal energy storage material, and the thermal energy is stored as a temperature change of a material based on the volumetric heat capacity of the material 106. For example, the heat storage material is water, oil, and the like. Optionally, the sensible thermal energy storage material 106 is a solid, a fluid and/or a gas. Optionally, the sensible thermal energy storage material is combination of fluids and/or gasses. For example, the sensible material is a mixture of water and oil, with a suspension of high volumetric heat capacity particles.

Optionally, the thermal energy storage material 106 is a phase change material, and the energy is stored as a volumetric heat capacity of the material and a heat of melting as the material 106 undergoes a phase change from solid to liquid. For example, the thermal energy storage material 106 is an alcohol, a sugar, a sugar alcohol, a salt, a wax, and the like or any combination thereof

Reference is now made to FIG. 4, which is a table of example phase change materials for thermal energy storage, according to some embodiments of the invention. The table 400 shows melting temperature in degrees Celsius, heat of fusion in kilojoules per kilogram, and density in kilograms per cubic meter. The example materials are a mixture of nitrate salts 401, Galactitol 402, D-mannitol 403, and a mixture of sodium nitrate and potassium nitrate 404. The melting temperatures of suitable phase change materials have a temperature above the minimum operating temperature of the application, and below the steady- state operational temperature of the heat transfer fluid.

Optionally, the thermal energy storage material 106 is chemical reaction thermal energy storage, and the energy is stored as heat of enthalpy of a chemical reaction. When heat is transferred from the heat transfer fluid to the elongated heat storage components, as at 106 and 107, the chemical reaction proceeds to convert the chemical reactants to the chemical products and absorb the heat in the process. During release of the heat, the products are converted to the reactants and heat is transferred to the fluid. For example, iron carbonate is used as a thermo-chemical material at a reaction temperature of 180 degrees centigrade, and a chemical reaction of FeC03 <-> FeO+C02 which releases and/or absorbs 2.6 gigajoule per cubic meter of material during the reaction. For example, calcium hydroxide is used as a thermo-chemical material at a reaction temperature of 500 degrees centigrade, and a chemical reaction of Ca(OH)2 <-> CaO+H20 which releases and/or absorbs 3.0 gigajoule per cubic meter of material during the reaction.

Reference is now made to FIG. 5, which is a graph of storage heat capacities versus reaction temperatures for phase change materials, thermo-chemical materials, and water, according to some embodiments of the invention. This graph 500 was presented originally by Gude in "Energy storage for desalination processes powered by renewable energy and waste heat sources" published in Applied Energy (2014) and available online July 19, 2014, at wwwdx(dot)doi(dot)org/ 10(dot) 1016/j (dot)apenergy(dot)2014(dot)06(dot)061. The graph 500 shows examples of a sensible material, in this case water 501, a range of phase change materials (PCM) 502, and a range of thermo-chemical materials (TCM) 503, with the corresponding ranges of working temperatures and heat storage capacities. The heat storage capacity for TCM is higher than sensible materials and PCM, but the available operating temperatures of PCM cover a larger range than TCM. It is expected that during the life of a patent maturing from this application many relevant heat storage materials will be developed and the scope of the term heat storage material is intended to include all such new technologies a priori.

Optionally, the outer shell 107 protects the heat storage material 106 from mixing with the heat transfer fluid, and/or improves thermal energy transfer rate between heat transfer fluid and heat storage material 106. For example, the outer shell 107 is a high temperature stainless steel canister with fins for increased heat transfer to the fluid and the heat storage material 106 has a phase change at 180 degrees centigrade.

Optionally, the heat storage material 106 is mixed with the heat transfer fluid in the lumen 104. For example, the heat storage material 106 crystallizes and precipitates into the heat transfer fluid when heat is absorbed. For example, the heat storage material 106 is a wax and/or thermo-plastic with a suitable melting temperature.

Optionally, the outer shell 107 has one or more coatings to increase thermal energy absorption from the heat transfer fluid by lowering the thermal resistance of the outer shell. The thermal coatings may provide thermal pathways through the outer shell 107. For example, a copper coating is used which has microscopic pores through the shell to decrease thermal resistivity of heat transfer from the heat transfer fluid through the outer shell 107 to the heat storage material 106.

Optionally, the outer shell 107 has included heat transfer fins for thermal energy transfer with the heat transfer fluid and/or heat storage material 106. Such as with electronic component heat sinks, the fins may be a profile that also increases the circulation of the heat transfer fluid for better thermal mixing. A higher surface area of the inner surface of the outer shell 107 may allow better thermal energy transfer to the heat storage material 106. For example, the inner shell surface of the outer has fins that help transfer thermal energy to the heat storage material 106 and/or act as nucleation points for phase change.

Optionally, the outer shell 107 has included internal and/or external heat transfer fins that have a dynamic response. For example, the heat transfer fins are modified with external control and/or by temperature changes to affect the heat transfer flux during the charge and/or discharge states of the system. For example, the dynamic response allows the fluid channel 100 to respond to load variations by the user, such as to enable more heat to be discharged from storage when demand is higher and/or more heat to recharge the storage when the application's demand is lower.

Optionally, the heat storage components flow along the lumen 104 with the heat transfer fluid. For example, small spherical outer shells 107 and/or canisters that contain heat transfer material 106, such as PCM. For example, the heat storage components recirculate with the HTF. For example, the heat storage components are microparticles.

Optionally, the elongated heat storage components, as at 106 and 107, are an array of elongated heat storage components distributed along the fluid channel lumen 104 to increase the surface area for thermal energy transfer. For example, a regular array of elongated heat storage components has a greater surface area of outer shell per volume of heat storage material 106 to allow improved heat transfer to the heat storage material 106. Optionally, the elongated heat storage component is a single continuous component along the lumen 104 of the fluid channel, such as a rod or profile shaped heat storage component. Optionally, the elongated heat storage components, as at 106 and 107, are transparent. For example, the outer shell 107 is a transparent material and the heat storage material 106 transparent when in the liquid phase. When in the solid phase, the heat storage material 106 may be opaque and absorbs solar radiation energy. Optionally, the elongated heat storage components are opaque. Optionally, the outer shell of the elongated heat storage components converts solar energy to thermal energy absorbed by the heat transfer fluid and/or the elongated heat storage components, as at 106 and 107. Optionally, a geometric shape cross section for the outer shell 107 allows an increase in surface area per unit length, such as a star shaped cross section. Optionally, the flow of the heat transfer fluid can be controlled, using means such as pumps, valves or nozzles to modify the rate of heat transfer to or from the heat storage material according to need.

It is expected that during the life of a patent maturing from this application many relevant outer shell technologies will be developed and the scope of the term outer shell is intended to include all such new technologies a priori.

Optionally, the heat storage material 106 is a phase change material, a sensible material, a thermo-chemical reaction material, and the like.

The heat transfer fluid is typically a liquid, but may be a gas. Optionally, the heat transfer fluid may be a mixture of liquid and gas. The relative position of the elongated heat storage components in the lumen 104 of the fluid channel may be in the center of the lumen, around the periphery of the lumen, along one side of the lumen, and the like. Patterns of the elongated heat storage components may enhance fluid flow through the lumen, to increase the surface area for heat transfer while maintaining good flow resistance.

The flowchart and block diagrams in the Figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and devices according to various embodiments of the present invention. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems that perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.

The descriptions of the various embodiments of the present invention have been presented for purposes of illustration, but are not intended to be exhaustive or limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terminology used herein was chosen to best explain the principles of the embodiments, the practical application or technical improvement over technologies found in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.

It is expected that during the life of a patent maturing from this application many relevant phase change materials will be developed and the scope of the term phase change material is intended to include all such new technologies a priori.

As used herein the term "about" refers to ± 10 %. The terms "comprises", "comprising", "includes", "including", "having" and their conjugates mean "including but not limited to". This term encompasses the terms "consisting of" and "consisting essentially of".

The phrase "consisting essentially of" means that the composition or method may include additional ingredients and/or steps, but only if the additional ingredients and/or steps do not materially alter the basic and novel characteristics of the claimed composition or method.

As used herein, the singular form "a", "an" and "the" include plural references unless the context clearly dictates otherwise. For example, the term "a compound" or "at least one compound" may include a plurality of compounds, including mixtures thereof.

The word "exemplary" is used herein to mean "serving as an example, instance or illustration". Any embodiment described as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments and/or to exclude the incorporation of features from other embodiments.

The word "optionally" is used herein to mean "is provided in some embodiments and not provided in other embodiments". Any particular embodiment of the invention may include a plurality of "optional" features unless such features conflict.

Throughout this application, various embodiments of this invention may be presented in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the invention. Accordingly, the description of a range should be considered to have specifically disclosed all the possible subranges as well as individual numerical values within that range. For example, description of a range such as from 1 to 6 should be considered to have specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6 etc., as well as individual numbers within that range, for example, 1, 2, 3, 4, 5, and 6. This applies regardless of the breadth of the range.

Whenever a numerical range is indicated herein, it is meant to include any cited numeral (fractional or integral) within the indicated range. The phrases "ranging/ranges between" a first indicate number and a second indicate number and "ranging/ranges from" a first indicate number "to" a second indicate number are used herein interchangeably and are meant to include the first and second indicated numbers and all the fractional and integral numerals therebetween.

It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination or as suitable in any other described embodiment of the invention. Certain features described in the context of various embodiments are not to be considered essential features of those embodiments, unless the embodiment is inoperative without those elements.

Although the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims.

All publications, patents and patent applications mentioned in this specification are herein incorporated in their entirety by reference into the specification, to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated herein by reference. In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the present invention. To the extent that section headings are used, they should not be construed as necessarily limiting.