Thermal energy storage blocks and associated support structures

Abstract

Thermal energy storage block comprising: one or more thermal radiation cavities; and a first set of fluid flow slots extending from and in fluid communication with a first thermal radiation cavity of the one or more thermal radiation cavities, such that the first set of fluid flow slots and the first thermal radiation cavity together define fluid flow paths through the thermal energy storage block.

Description

THERMAL ENERGY STORAGE BLOCKS AND ASSOCIATED SUPPORTSTRUCTURESCROSS-REFERENCE TO RELATED APPLICATIONS[I] This application claims priority under the Paris Convention to:[2] U.S. Provisional Patent Application No. 63 / 459,540 filed on April 14, 2023,[3] U.S. Provisional Patent Application No. 63 / 578,139 filed on August 22, 2023,[4] U.S. Provisional Patent Application No. 63 / 626,501 filed on January 29. 2024, and[5] U.S. Provisional Patent Application No. 63 / 627,523 filed on January 31, 2024.BACKGROUND[6] Technical Field[7] The present disclosure relates to thermal energy storage blocks for use in thermal energy storage and utilization systems. More particularly, the present disclosure relates to an energy storage block that may store electrical energy in the form of thermal energy, which can be used for the supply of hot air, nitrogen, argon, carbon dioxide (CO2), steam, process gas. inert gas, hydrogen, or other heated fluids, for various applications including the supply of heat for power generation. The present disclosure also relates to support structures for thermal energy storage blocks, including support blocks, sleepers, and slabs. Such support structures may provide structural support and physical and thermal separation of thermal energy storage blocks from surrounding structures.[8] I. Thermal Energy Systems[9] A. Variable Renewable Electricity

[0010] The combustion of fossil fuels has been used as a heat source in thermal electrical power generation to provide heat and steam for uses such as industrial process heat. The use of fossil fuels has various problems and disadvantages, however, including global warming and pollution. Accordingly, there is a need to switch from fossil fuels to clean and sustainable energy.[II] Variable renewable electricity (VRE) sources such as solar power and wind power have grown rapidly, as their costs have reduced as the world moves towards lower carbon emissions to mitigate climate change. But a major challenge relating to the use of VRE is, as its name suggests.its variability. The variable and intermittent nature of wind and solar power does not make these types of energy sources natural candidates to supply the continuous energy demands of electrical grids, industrial processes, etc. Accordingly, there is an unmet need for storing VRE to be able to efficiently and flexibly deliver energy at different times.

[0012] Moreover, the International Energy Agency has reported that the use of energy by industry comprises the largest portion of world energy use, and that three-quarters of industrial energy’ is used in the form of heat, rather than electricity. Thus, there is an unmet need for lower-cost energy storage systems and technologies that utilize VRE to provide industrial process energy, which may expand VRE and reduce fossil fuel combustion.

[0013] B. Storage of Energy as Heat

[0014] Thermal energy in industrial, commercial, and residential applications may be collected during one time period, stored in a storage device, and released for the intended use during another period. Examples include the storage of energy' as sensible heat in tanks of liquid, including water, oils, and molten salts; sensible heat in solid media, including rock, sand, concrete and refractory materials; latent heat in the change of phase between gaseous, liquid, and solid phases of metals, waxes, salts and water; and thermochemical heat in reversible chemical reactions which may absorb and release heat across many repeated cycles; and media that may combine these effects, such as phase-changing materials embedded or integrated with materials which store energy as sensible heat. Thermal energy may be stored in bulk underground, in the form of temperature or phase changes of subsurface materials, in contained media such as liquids or particulate solids, or in self-supporting solid materials.

[0015] Electrical energy storage devices such as batteries typically transfer energy mediated by a flowing electrical current. Some thermal energy storage devices similarly transfer energy into and out of storage using a single heat transfer approach, such as convective transfer via a flowing liquid or gas heat transfer medium. Such devices use “refractory ’" materials, which are resistant to high temperatures, as their energy’ storage media. These materials may be arranged in configurations that allow the passage of air and combustion gases through large amounts of material.

[0016] Some thermal energy systems may, at their system boundary, absorb energy in one form, such as incoming solar radiation or incoming electric power, and deliver output energy in a different form, such as heat being carried by a liquid or gas. But thermal energy storage systemsmust also be able to deliver storage economically. For sensible heat storage, the range of temperatures across which the bulk storage material — the “storage medium” — can be heated and cooled is an important determinant of the amount of energy that can be stored per unit of material. Thermal storage materials are limited in their usable temperatures by factors such as freezing, melting, softening, boiling, or thermally driven decomposition or deterioration, including chemical and mechanical effects.

[0017] Further, different uses of thermal energy — different heating processes or industrial processes — require energy at different temperatures. Electrical energy storage devices, for example, can store and return electrical energy at any convenient voltage and efficiently convert that voltage up or down with active devices. On the other hand, the conversion of lower- temperature heat to higher temperatures is intrinsically costly and inefficient. Accordingly, a challenge in thermal energy storage devices is the cost-effective delivery of thermal energy with heat content and at a temperature sufficient to meet a given application.

[0018] Some thermal energy storage systems store heat in a liquid that flows from a “cold tank” through a heat exchange device to a “hot tank” during charging, and then from the hot tank to the cold tank during discharge, delivering relatively isothermal conditions at the system outlet during discharge. Systems and methods to maintain sufficient outlet temperature while using low er-cost solid media are needed.

[0019] Thermal energy storage systems generally have costs that are primarily related to their total energy storage capacity (how many MWh of energy are contained within the system) and to their energy transfer rates (the MW of instantaneous power flowing into or out of the energy' storage unit at any given moment). Within an energy storage unit, energy is transferred from an inlet into storage media, and then transferred at another time from storage media to an outlet. The rate of heat transfer into and out of storage media is limited by factors including the heat conductivity' and capacity of the media, the surface area across which heat is transferring, and the temperature difference across that surface area. High rates of charging are enabled by high temperature differences between the heat source and the storage medium, high surface areas, and storage media with high heat capacity and / or high thermal conductivity.

[0020] Each of these factors can add significant cost to an energy storage device. For example, larger heat exchange surfaces commonly require 1) larger volumes of heat transfer fluids, and 2)larger surface areas in heat exchangers, both of which are often costly. Higher temperature differences require heat sources operating at relatively higher temperatures, which may cause efficiency losses (e.g. radiation or convective cooling to the environment, or lower coefficient of performance in heat pumps) and cost increases (such as the selection and use of materials that are durable at higher temperatures). Media with higher thermal conductivity and heat capacity may also require selection of costly higher-performance materials or aggregates.

[0021] Another challenge of systems storing energy from VRE sources relates to rates of charging. A VRE source, on a given day, may provide only a small percentage of its energy during a brief period of the day, due to prevailing conditions. For an energy storage system that is coupled to a VRE source and that is designed to deliver continuous output, all the delivered energy must be absorbed during the period when incoming VRE is available. As a result, the peak charging rate may be some multiple of the discharge rates (e.g., 3-5x), for instance, in the case of a solar energy system, if the discharge period (overnight) is significantly longer than the charge period (during daylight). In this respect, the challenge of VRE storage is different from, for example, that of heat recuperation devices, which typically absorb and release heat at similar rates. For VRE storage systems, the design of units that can effectively charge at high rates is important and may be a higher determinant of total system cost than the discharge rate.

[0022] C. Thermal Energy Storage Problems and Disadvantages

[0023] The above-described approaches have various problems and disadvantages. Earlier systems do not take into account several critical phenomena in the design, construction, and operation of thermal energy storage systems, and thus does not facilitate such systems being built and efficiently operated. More specifically, current designs fail to address “thermal runaway'’ and element failure due to non-uniformities in thermal energy charging and discharging across an array of solid materials, including the design of charging, discharging, and unit controls to attain and restore balances in temperature across large arrays of thermal storage material.

[0024] Thermal energy storage systems with embedded radiative charging and convective discharging are in principle vulnerable to “thermal runaway” or “heat runaway” effects. The phenomenon may arise from imbalances, even small imbalances, in local heating by heating elements and in cooling by heat transfer fluid flow. The variations in heating rate and cooling rate, unless managed and mitigated, may lead to runaway temperatures that cause failures of heatersand / or deterioration of refractory materials. Overheating causes early failures of heating elements and shortened system life. In Stack, for example, the blocks closest to the heating wire are heated more than the blocks that are further away from the heating wire. As a result, the failure rate for the wire is likely to increase, reducing heater lifetime.

[0025] One effect that further exacerbates thermal runaway is the thermal expansion of air flowing in the air conduits. Hotter air expands more, causing a higher outlet velocity for a given inlet flow, and thus a higher hydraulic pressure drop across the conduit, which may contribute to a further reduction of flow and reduced cooling during discharge. Thus, in successive heating and cooling cycles, progressively less local cooling can occur, resulting in still greater local overheating.

[0026] The effective operation of heat supply from thermal energy storage relies upon continuous discharge, which is a particular challenge in systems that rely upon VRE sources to charge the system. Solutions are needed that can capture and store that VRE energy in an efficient manner and provide the stored energy' as required to a variety' of uses, including a range of industrial applications, reliably and without interruption.

[0027] Previous systems do not adequately address problems associated with VRE energy sources, including variations arising from challenging weather patterns such as storms, and longer-term supply variations arising from seasonal variations in VRE generation. In this regard, there is an unmet need in the art to provide efficient control of energy storage system charging and discharging in smart storage management. Current designs do not adequately provide storage management that considers a variety of factors, including medium-term through short-term weather forecasts, VRE generation forecasts, and time-varying demand for energy, which may be determined in whole or in part by considerations such as industrial process demand, grid energy demand, real-time electricity prices, wholesale electricity market capacity prices, utility resource adequacy value, and carbon intensity of displaced energy' supplies. A system is needed that can provide stored energy to various demands that prioritizes by taking into account these factors, maximizing practical utility' and economic efficiencies.

[0028] There are a variety of unmet needs relating generally to energy, and more specifically, to thermal energy7. Generally, there is a need to switch from fossil fuels to clean and sustainable energy. There is also a need to store VRE to deliver energy7at different times in order to help meet society’s energy needs. There is also a need for lower-cost energy storage systems andtechnologies that allow VRE to provide energy for industrial processes, which may expand the use of VRE and thus reduce fossil fuel combustion. There is also a desire to maintain sufficient outlet temperature while using lower-cost solid media.

[0029] Still further, there is a need to design VRE units that can be rapidly charged at low cost, supply dispatchable, continuous energy as required by various industrial applications despite variations in VRE supply, and that facilitate efficient control of charging and discharging of the energy storage system.

[0030] II. Storage of Intermittent Energy

[0031] Fossil fuels have driven the world economy since the industrial revolution; however, mankind has discovered that not only is there a limited supply of these energy resources, but also that the combustion of fossil fuels to extract their energy produces greenhouse gases and other pollutants that threaten planet-wide ecosystems. Specifically, such systems are inherently inefficient in their use of the energy locked up in chemical bonds because they emit innumerable tons of hot combustion gases out smokestacks into our atmosphere, directly causing global warming, indirectly causing global warming through the effects of greenhouse gas emissions on the increased absorption of sunlight by planet Earth, as well as the effects of the pollutants’ contribution to the degradation of our planet through, for example, the washing of the Earth’s various ecosystems in acid rain.

[0032] Energy sources that address this problem, such as solar energy, wind energy, and tidal energy are being developed to meet our need for renewable energy sources that do not generate these harmful greenhouse gases. One drawback that renewable energy sources have is that they are of an intermittent nature. The sun does not always shine; the wind does not always blow; tides are not always flowing. This has prevented these technologies from becoming replacements for fossil fueled energy sources, since industry requires power on demand, 24 hours a day, 365 days a year.

[0033] Therefore, what is needed is a way to store the intermittent energy that renewable energy sources provide in a closed loop to meet the constant power demands of industry' without expelling heat and pollutants to the atmosphere. This has led to the development of green energy' storage solutions, as well as the systems and methods for heat storage and extraction from structured solid blocks in thermal energy storage units as described herein.

[0034] One hurdle that lies between the conception and initial development of thermal storage solutions and their actual implementation is the interfacing of such solutions with existing industrial equipment to make use of existing assets and infrastructure. Consequently, what is needed are systems for the modularization of such thermal energy storage units that may be combined in various fashions to provide for customized solutions that meet the individual needs for retrofitting such fossil fuel fired power systems. Furthermore, there is a great need to enable the evaluation of thermal energy storage units as a green energy alternative to existing fuel fired boiler systems without redesigning and rebuilding existing industrial infrastructure. Along these lines, what is desperately needed are systems that allow for easily switching between fossil fuel energy sources and variable renewable electricity sources to evaluate the latter as replacements for existing fossil fuel fired energy sources. This would greatly help achieve the worldwide goals set forth in the Paris Climate Accord, in particular a 45% reduction in greenhouse gas emissions by 2030. with a net zero emission goal target set for 2050. In particular, systems and methods for the coupling of one or more thermal energy storage units to fuel fired boiler systems is needed, along with control systems that coordinate the operation of systems containing multiple thermal energy storage units. This coupling of two completely different energy sources allows for reversibly evaluating this new sustainable technology for the possible retrofitting or replacement of the fossil fuel based systems with a green energy supply, while retaining much of the capital equipment that is already paid for and in service.

[0035] III. Industrial Applications of Stored Thermal Energy

[0036] The steel industry accounts for as much as 5% of total world greenhouse gas emissions because of its significant use of coal. Traditional steel making process using refined coal generates about two tons of carbon dioxide (CO2) for every ton of steel produced. Low CO2 emitting steelmaking and ironmaking solutions are being developed to reduce the amount of greenhouse gas emissions associated with the steel and iron industries.

[0037] One such solution involves Direct-Reduced Iron (DRI), also known as sponge iron. DRI is a key process step in one of two major process pathways to produce steel from iron oxide ore. DRI refers to a solid-state process which reduces iron oxides to metallic iron at temperatures below the melting point of iron. In the global effort to reduce greenhouse gas emissions, DRI is becoming the preferred pathw ay for producing steel due to the potential for emission reductions that are not matched by the blast furnace pathway. Although a step in the right direction, traditional DRIprocesses continue to rely on carbon emitting sources to provide sufficient heat to drive the DRI process.SUMMARY

[0038] In accordance with a first aspect of the invention, there is provided a thermal energy storage block comprising: one or more thermal radiation cavities; and a first set of fluid flow slots extending from, and in fluid communication with, a first thermal radiation cavity of the one or more thermal radiation cavities, such that the first set of fluid flow slots and the first thermal radiation cavity together define fluid flow pathways through the thermal energy’ storage block.

[0039] The thermal energy storage block may be formed of a thermal energy' storage material, optionally comprising concrete.

[0040] The thermal energy' storage block may further comprise one or more interlock features on an external surface of the thermal energy7storage block, w herein the one or more interlock features are configured to be inserted into engagement with one or more corresponding interlock features on another of said thermal energy storage blocks, thereby enabling a stacking arrangement.

[0041] The interlock features may' comprise protrusions and / or recesses.

[0042] One of more of the protrusions may be provided on an upper surface of the thermal energy storage block, and one or more of the recesses may be provided on a lower surface of the thermal energy storage block opposing the upper surface, and wherein the recesses are shaped, or configured, to receive the protrusions.

[0043] The fluid flow slots may be arranged in a first direction that is parallel to the upper surface and lower surface of the thermal energy storage block.

[0044] The thermal energy7storage block may further comprise a second set of fluid flow slots extending from, and in fluid communication with, a second thermal radiation cavity of the one or more thermal radiation cavities, such that the second set of fluid flow slots and the second thermal radiation cavity7together define further fluid flow7pathways through the thermal energy' storage block.

[0045] The thermal energy storage block may further comprise a third set of fluid flow slots extending from, and in fluid communication with, a third thermal radiation cavity of the one or more thermal radiation cavities, such that the third set of fluid flow slots and the third thermal radiation cavity together define further fluid flow pathways through the thermal energy storage block.

[0046] At least one side wall of the thermal energy storage block may be configured to define a partial thermal radiation cavity, such that, in use, a further thermal radiation cavity is formed when the thermal energy storage block is adjacent another of said thermal energy storage blocks.

[0047] The at least one side wall may be recessed in order to define the partial radiation cavity'.

[0048] The thermal energy storage block may further comprise a fourth set of fluid flow slots extending from, and in fluid communication with, the partial thermal radiation cavity, such that the fourth set of fluid flow slots and the partial thermal radiation cavity together define additional fluid flow pathways through the thermal energy storage block.

[0049] Diagonally opposite portions of the thermal energy storage block may be recessed to define partial thermal radiation cavities, such that, in use, further thermal radiation cavities are formed when the thermal energy storage block is placed adjacent to others of said thermal energy storage blocks.

[0050] The thermal radiation cavities may extend through a portion of the thermal energy storage block and the fluid flow slots may extend through the remaining portion of the thermal energy storage block.

[0051] The thermal storage block may be formed in a tessellating shape.

[0052] The tessellating shape may comprise an asymmetric shape or an order two rotationally symmetric shape, optionally comprising a zig-zag shape or a wave-profile shape.

[0053] At least some of the fluid flow slots may have a different sized and / or shaped opening than some others of the fluid flow slots.

[0054] The thermal energy storage block may further comprise: an upper solid platform portion; and a lower solid base portion, wherein the fluid flow slots are arranged in a first direction that isparallel to the upper solid platform portion and the lower solid base portion, and wherein the thermal radiation cavity extends between the upper solid platform and the lower solid base portion in a second direction perpendicular to first direction.

[0055] The thermal energy storage block may further comprise apertures formed in the upper solid platform portion and / or in the lower solid base portion to facilitate the passage of air therein.

[0056] The thermal energy storage block may further comprise one or more integrated ledges for supporting heater elements adjacent to the one or more thermal radiation cavities.

[0057] In a further aspect there is provided a support block for the thermal energy7storage block, the support block comprising: an upper platform portion; a base portion opposing the upper platform portion; a hollow channel between the upper platform portion and the base portion, the hollow channel defining a fluid flow pathway through the support block; and interlock features provided on the upper platform and on the underside of the base portion of the support block and configured to engage the one or more interlock features of the thermal energy storage block.

[0058] The support block may further comprise first and second opposing support walls extending between the upper platform portion and the base portion, wherein hollow channel is bound by the upper platform portion, the base portion, and the first and second opposing support walls.

[0059] At least one side wall of the support block may be recessed, such that, in use, one or more further hollow channels are formed when the support block is placed adjacent to another of said support blocks, thereby defining one or more further fluid flow pathways.

[0060] The interlock features may comprise a plurality of protrusions on the upper platform portion, and a plurality of recesses shaped, or configured, to receive the protrusions on the underside of the base portion.

[0061] The protrusions on the upper platform portion may be configured to engage the recesses in the lower surface of the thermal energy storage block, such that the support block is configured to support said thermal energy7storage block thereon.

[0062] In a further aspect there is provided an assembly comprising the thermal energy7storage block supported on the support block.

[0063] In a further aspect there is provided an assembly comprising a plurality of stacked thermal energy storage blocks, wherein the thermal energy storage blocks in a given layer of the stack are laterally offset relative to the thermal energy' storage blocks in the layer below, such that the recesses on the underside of a given block in the given layer are engaged by protrusions on a plurality of blocks in the layer below.

[0064] In a further aspect there is provided a thermal energy' storage block formed in a generally parallelepiped shape, the block comprising: a plurality' of fluid flow slots extending in a first direction through the block, the plurality of fluid flow slots defining fluid flow pathways through the block; and at least one chamfered edge in a second direction generally perpendicular to the first direction such that, in use, the block is configured to abut at least another of said blocks with the respective chamfered edges engaged to define a thermal radiation cavity'.

[0065] The block may comprise two chamfered edges in the second direction, such that, in use, the block is configured to abut at least two other of said blocks with the respective chamfered edges engaged to define a thermal radiation cavity between the blocks, the thermal radiation cavity' in fluid communication with the fluid flow slots to define a fluid flow pathway therethrough.

[0066] The thermal energy' storage may further comprise one or more integrated ledges configured to support one or more heater elements.

[0067] In a further aspect there is provided a support slab for the thermal energy storage block, the support slab having a plurality of recessed bays formed in an upper surface thereof, the recessed bays each shaped and configured to retain said thermal energy' storage block therein, wherein the recessed bays are spaced apart and formed in rows, and wherein the recessed bays in adjacent rows are offset, such that, when said blocks are disposed in respective bays, the blocks form thermal radiation cavities therebetween.

[0068] The recessed bays in adjacent rows may be offset such that a recessed bay in one row aligns with the center of a gap between consecutive recessed bays in the adjacent row.

[0069] The support slab may further comprise a plurality' of recessed bays formed in an underside surface, opposing the upper surface, said bays corresponding to the bays formed in the upper surface of the support slab, thereby, in use, enabling a stacked arrangement of thermal energy storage blocks with the support slab disposed between adjacent layers of the stack.

[0070] In a further aspect there is provided an assembly comprising a plurality of the thermal energy storage blocks, each provided in a respective recessed bay on the support slab.BRIEF DESCRIPTION OF DRAWINGS

[0071] The accompanying drawings are included to provide a further understanding of the present disclosure and are incorporated in and constitute a part of this specification. The drawings illustrate example implementations of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0072] Figure 1 illustrates a schematic perspective view of a thermal energy storage block according to the example implementations;

[0073] Figure 2 illustrates a perspective view of the underside of the thermal energy’ storage block according to the example implementations;

[0074] Figure 3a illustrates a front view of the thermal energy storage block according to the example implementations;

[0075] Figure 3b illustrates a cross-sectional side view of the thermal energy storage block according to the example implementations;

[0076] Figure 4 illustrates a plan view of the thermal energy storage block according to the example implementations;

[0077] Figure 5a illustrates a side view of the thermal energy storage block according to the example implementations;

[0078] Figure 5b illustrates a cross-sectional plan view of the thermal energy storage block according to the example implementations;

[0079] Figure 6a illustrates a side view of the thermal energy storage block according to the example implementations;

[0080] Figure 6b illustrates another cross-sectional plan view of the thermal energy storage block according to the example implementations;

[0081] Figure 7a illustrates a side view of a stacked assembly of thermal energy storage blocks according to the example implementations;

[0082] Figure 7b illustrates a cross-sectional view of a stacked assembly of thermal energy storage blocks according to the example implementations;

[0083] Figure 7c illustrates a close-up view of interlock features of the thermal energy' storage block according to the example implementations;

[0084] Figure 7d illustrates a plan view of a stacked assembly of thermal energy storage blocks according to the example implementations;

[0085] Figure 7e illustrates a perspective view of a stacked assembly of thermal energy' storage blocks according to the example implementations;

[0086] Figure 7f illustrates a perspective view of a stacked assembly of thermal energy’ storage blocks including heating elements according to the example implementations;

[0087] Figure 8 illustrates a schematic perspective view of a thermal energy storage block according to the example implementations;

[0088] Figure 9a illustrates a schematic perspective view of a thermal energy storage block according to the example implementations;

[0089] Figure 9b illustrates a schematic perspective view of a thermal energy storage block according to the example implementations;

[0090] Figure 9c illustrates a schematic perspective view of an underside of a thermal energystorage block according to the example implementations;

[0091] Figure 10a illustrates a schematic perspective view of a support block for a thermal energy' storage block according to the example implementations;

[0092] Figure 10b illustrates a schematic perspective view of an underside of a support block for a thermal energy' storage block according to the example implementations;

[0093] Figure I la illustrates a front view of a support block for a thermal energy storage block according to the example implementations;

[0094] Figure l ib illustrates a plan view of a support block for a thermal energy storage block according to the example implementations;

[0095] Figure 11c illustrates a view of the underside of a support block for a thermal energy’ storage block according to the example implementations;

[0096] Figure 12 illustrates a schematic perspective view of a thermal energy storage block according to the example implementations;

[0097] Figure 13a illustrates a perspective view of an assembly of thermal energy storage blocks arranged on support slabs according to the example implementations;

[0098] Figure 13b illustrates a perspective view of an assembly of thermal energy storage blocks arranged on support slabs with heating elements according to the example implementations;

[0099] Figure 14 illustrates a cross-sectional perspective view of an assembly of thermal energy’ storage blocks arranged on support slabs according to the example implementations;

[0100] Figure 15 illustrates a plan view of an assembly of thermal energy’ storage blocks arranged on support slabs according to the example implementations:

[0101] Figure 16 illustrates a side vieyv of an assembly of thermal energy storage blocks arranged on support slabs according to the example implementations;

[0102] Figure 17a illustrates a schematic perspective view of a top side of a support slab for thermal energy storage blocks according to the example implementations;

[0103] Figure 17b illustrates a schematic perspective view of a bottom side of a support slab for thermal energy storage blocks according to the example implementations.DETAILED DESCRIPTION

[0104] Aspects of the example implementations, as disclosed herein, relate to thermal energy' storage blocks and associated support blocks and support slabs for use in thermal energy’ storage systems for various industrial applications.

[0105] The structure and shape of the blocks is configured for repeated heating and cooling, for the purpose of storing energy. When implemented in athermal energy storage system, energy input is provided in the form of electrical energy , which heats wires, filaments, rods, or other solid conductive materials to emit radiant thermal energy. The energy output is in the form of heat delivered in a circulating gas introduced at one portion of a structure incorporating the blocks, and which leaves another portion of the structure at a higher temperature.

[0106] The blocks may be in the form of one or more cast or extruded shapes, and arranged so as to have an alternating sequence, along both vertical and horizontal axes. The structure includes a plurality of open cavities or chambers and blocks, with the blocks including air passages having at least one dimension which is much smaller than the other two dimensions. The passages are open to the chambers and are internally exposed to a radiating surface heated by electrical resistance. In the chambers, heat is transferred by thermal radiation from relatively hotter surfaces to relatively cooler surfaces.

[0107] Figure 1 shows a schematic perspective view of a thermal energy storage block 100 according to one implementation. The block 100 is formed of a thermal storage material, which may be concrete and / or refractory materials.

[0108] The block 100 includes fluid flow slots 102, or channels, provided a first direction (horizontally) through a portion of the block. The plurality of the fluid flow slots 102 may be shaped so as to be wider than they are tall and may have a continuous cross section along their length. The fluid flow slots permit the passage of a fluid therethrough, such as air, nitrogen, argon, carbon dioxide (CO2), steam, process gas, inert gas, hydrogen, or other heated fluids.

[0109] Additionally provided are thermal radiation cavities 104 formed in the block, defining a space into which thermal energy may radiate onto exposed surfaces of the block, from adjacent electrical heaters, to transfer thermal energy thereto. The thermal radiation cavities 104 each extend from the lower solid base portion 120 of the block to the upper solid platform portion 130, in a second direction perpendicular to the first direction. By virtue of extending into the block, the thermal radiation cavities provide a large surface area onto which thermal energy may radiate from adjacent heater elements (not shown), to transfer thermal energy to the material of the thermal energy storage block with high efficiency.[HO] Thermal radiation cavities 104 are provided in opposing faces of the block, in a staggered, or offset, configuration, with their openings provided on the two opposing faces. Consequently, a face of the block into which fluid flows into or out of is defined by an alternating arrangement of fluid flow slots 102 and thermal radiation cavities 104.[Hl] A partial thermal radiation cavity 106 is also formed by a recessed side wall 114 of the block 100. The partial thermal radiation cavity 106 becomes a full radiation cavity when the block 100 is placed adjacent to another of the blocks 100. In particular, the side wall of an adjacent block 100 forms the remaining wall to make the partial radiation cavity a full radiation cavity.

[0112] A set of fluid flow slots 102 extends from, and is in fluid communication with, each of the thermal radiation cavities 104. including the partial thermal radiation cavity 106. Consequently, the set of fluid flow slots and the respective thermal radiation cavity together define fluid flow pathways through the energy storage block. Such pathways are generally in the first direction (horizontally).

[0113] The block 100 includes one or more integrated ledges 110. The ledges 110 can be used to support heater elements in a gaps between row-s of thermal storage blocks 100, in proximity' to the thermal radiation cavities, as discussed in further detail below-.

[0114] The block 100 also includes apertures 112 through the upper solid platform portion 130 and through the lower solid base portion 120 of the block 100. These apertures 112 may be the same or different sized and / or shaped relative to the other fluid flow slots 102 in the thermal energy storage block 100. The apertures 112 allow for excess heat in an otherwise solid section of the storage block to be dissipated to reduce structural stress that might occur if that solid section were to retain too much heat, relative to the rest of the thermal storage block. The apertures may extend through the entirety of the block, thereby defining a fluid flow pathway through the block. In an alternative implementation, the upper solid platform portion 130 and through the lower solid base portion 120 of the block 100 are closed, without apertures or pathways through them, for increased structural strength.

[0115] Figure 1 also shows interlock features 108 provided on the upper surface of the upper solid platform portion 130 of the block 100. As show n in Figure 2, corresponding interlock features 216 are provided on the underside of the lower solid base portion of the block 100, and which are configured, or shaped, to be engaged by the interlock features 108 provided on the upper surfaceof the block 100. Consequently, the blocks may be stacked, with the interlock features 108 on the upper surface of one block engaging a corresponding interlock feature 216 on the underside of a block above. The interlock features resist side-to-side movement and can also maintain alignment when there is vertical movement.

[0116] The interlock features 108, 216, may be in the form of protrusions (or lugs), and recesses. As show n in Figures 1 and 2, the interlock features are arranged in a regular pattern, such as in a square or rectangle arrangement on each surface. The spacing between the interlock features is provided so as to permit a staggered and overlapping stacking arrangement (as discussed further below).

[0117] Figure 3a depicts a front view of the thermal energy storage block 100. As explained above, this face of the block, into which fluid flows into or out of. has by an alternating arrangement of columns of fluid flow slots 102 and thermal radiation cavities 104. As shown, there are also fluid flow slots 102 extending from the far end of the radiation cavity 104, from within the block 100 to the opposing face of the block 100. Consequently, the opposing face of the block to that depicted in Figure 3a has the same appearance as the face that is shown.

[0118] Figure 3b show-s a cross-sectional view of the block along section E-E as shown in Figure 3a. As shown in Figure 3b, the fluid flow slots 102 extend from, and are in fluid communication with, the respective thermal radiation cavity 104. The apertures 112 also extend through the entire depth of the block, thereby defining a further fluid flow pathway through the block.

[0119] Figure 4 depicts a plan view of the block 100. As viewed from above, the block 100 has an asymmetric shape relative to a longitudinal axis shown by dotted line 410. The block 100 has two sides with straight edges 430, 432. and two shaped edges 420 422 having a shape such as, but not limited to, a wave-shaped profile or a zig-zag profile. In other words, the edges 420 and 422 may have a cutaw ay portion in diagonally opposite regions.

[0120] Figure 5a shows a side view of the block 100, corresponding to the block 100 as depicted in Figure 3a rotated by 90 degrees about a central vertical axis. The partial thermal radiation cavity 106 at one side of the block is shown.

[0121] Figure 5b shows a cross-sectional view of block 100 along line D-D as indicated in Figure 5a. The cross-section is between the fluid flow slots 102, such that the slots 102 are not visible inthe cross-sectional view. The cross-sectional view shows the staggered arrangement of the thermal radiation cavities 104 on opposing sides of the block 100. The thermal radiation cavities 104 extend into the body of the block 100. As shown, the cavities may extend to close to halfway into the depth of the block. The thermal radiation cavities 104 may also be provided with an opening 510 that widens. Such openings 510 assist with funneling fluid into the cavities and ultimately into the fluid flow slots 102.

[0122] Figure 6a shows a side view of the block 100, corresponding to the view shown in Figure 5a. Figure 6b shows a cross-sectional view of block 100 along line E-E as indicated in Figure 6a. This cross-section is at a different height to that of the cross-section depicted in Figure 5b. In this case, the cross-section intersects a layer of fluid flow slots 102. As shown, the fluid flow slots 102 extend from the rear of each of the thermal radiation cavities to the opposing face of the block, such that the thermal radiation cavities 104, 106, and the fluid flow slots 102 together define fluid flow pathways through the block.

[0123] Figure 7a shows a side view of a stacked assembly 700, or structure, of blocks 100. Each block 100 is shown from the side view, as depicted in Figures 5a and 6a, with the fluid flow slots (not shown) extending horizontally. From the illustrated side view, there are gaps 710 between each of the blocks 100 in a row. The blocks in the layer above are staggered, or laterally offset, relative to the blocks 100 in the row below.

[0124] Figure 7b shows a cross-sectional view of the assembly along line A-A as shown in Figure 7a. As shown in this cross-section, there are no gaps between adjacent blocks in a row in the same layer, as the blocks tesselate.

[0125] Figure 7c shows a close-up view of the region labelled as “B?’ in Figure 7b. As shown, a protrusion 108 on the upper surface of a block 100 in the lower layer engages a recess 216 in the underside of a block 100 in the layer above in the stacked arrangement.

[0126] Figure 7d shows a plan view of the stacked assembly 700. The blocks 100 are arranged to tesselate to form rows in a first direction, and to have gaps 710 between each such row in a given layer, in a second direction perpendicular to the first direction. The blocks 100 in the layer above are laterally offset in both the first direction and a second direction (perpendicular to the first direction), such that they straddle the gaps 710. As a result, the gaps 710 in adjacent layers of the stack are also offset. Each block 100 in the layer above engages four different blocks 100 in thelayer below. Consequently, the recesses 216 of a given block 100 in the upper layer are engaged by protrusions 108 on four different blocks 100 in the layer below.

[0127] Figure 7e shows a perspective view of the stacked assembly 700, in which the offsetting, tessellation and gaps between the blocks, as explained above, are shown.

[0128] As shown in Figure 7f, the gaps between the adjacent rows of blocks are provided to accommodate electrical heating elements 740, in order to transfer thermal energy to the blocks for storing therein. The electrical heating elements 740 are arranged so as to be adjacent to the thermal radiation cavities 104. The heating elements 740 may be arranged to span a row of thermal energy storage blocks 100. The heating elements can be held by a support structure (not shown) that engages the integrated ledges 110 in the blocks. The support structure (not shown) may span the gap between rows of blocks so as to engage the integrated ledges 110 on both sides of the gap.

[0129] Figure 8 shows an alternative implementation of a block 800. The block 800 has corresponding features to block 100 as described above. Corresponding features of the block are labelled with like reference numerals. The block 800 is provided in a wider format than block 100. In particular, the wider block 800 has additional rows of thermal radiation cavities 104 and fluid flow slots 102. As visible on the illustrated face, there are three thermal radiation cavities 104, one partial radiation cavity 106, and four sets (or columns) of fluid flow slots 102. Corresponding cavities 106 are slots 102 are also formed in the opposing face (not shown). A given block 800 is provided with 8 protrusions 108 on its upper surface, and 8 corresponding recesses (not shown) on its underside. The wider format of block 800 allows for fewer blocks to be used in forming a stacked assembly, of a given thermal storage capacity, than when smaller blocks (such as block 100) are used.

[0130] Figure 9 shows another alternative implementation of a block 900. The block 900 has corresponding features to block 100 as described above. Corresponding features of the block are labelled with like reference numerals. The block 900 is provided in a deeper format than block 100. From a front view, the block 900 corresponds to block 100. in terms of the number of thermal radiation cavities and columns of slots. With the deeper structure, the fluid flow slots 102 and thermal radiation cavities 104 also are required to extend further, between the opposing faces of the block, w hich are separated by a greater distance. The block 900 is provided with 6 protrusions 108 on its upper surface and 6 corresponding recesses 216 on its underside, as shown in Figure 9c.

[0131] Figures 10a and 10b show perspective views of a support block 1000, or sleeper, for supporting the thermal energy storage blocks described above. The support block 1000 is designed to provide fluid flow from below the thermal energy' storage blocks, and to provide thermal isolation of the thermal energy storage blocks from a surrounding medium. In particular, the thermal energy storage blocks may be heated to high temperatures that cannot be tolerated by the surrounding medium or structure.

[0132] As shown in Figure 10a, the support block 1000 is provided with an upper platform portion 1120. an opposing base portion 1130, and a hollow channel 1002 between the upper platform portion 1 120 and the base portion 1130. The hollow channel 1 120 defines a fluid flow pathway through the support block, to allow fluid flow around a stacked structure of thermal energy storage blocks.

[0133] First and second opposing support walls 1040, 1042 extend between the upper platform portion 1120 and the base portion 1130. The hollow channel 1002 is bound by the upper platform portion, the base portion, and the first and second opposing support walls.

[0134] The side walls 1030 of the block are recessed, or indented, such that, in use, one or more further hollow channels are formed when the support block is placed adjacent to another of said support blocks, thereby defining one or more further fluid flow pathways. In other words, the upper platform portion 1120 and the base portion 1130 laterally extend beyond the support walls 1040, 1042. to create a recessed region which forms a partial channel.

[0135] The support block 100 is also provided with interlock features in the form of protrusions 1108 on the upper surface of the upper platform portion of the support block. Such protrusions 1108 correspond in their form and purpose to those of the thermal energy storage block, as described above. The protrusions 1108 and can engage recesses 216 in an underside of a thermal energy storage block, and thereby support a thermal energy' storage block on the upper platform portion of the support block 1000. As depicted, 4 protrusions may be provided in a square or rectangular arrangement.

[0136] As shown in Figure 10b, the support block 1000 may also be provided with interlock features on the underside of the base portion 1130 of the support block 1000. Such interlock features can be in the form of recesses 1116 which are configured, shaped and arranged, to be engaged by the protrusions 1108.

[0137] Figure 1 la shows a front elevation view of the support block 1000. As shown, the hollow region 1002 provides a fluid flow pathway extending through the support block.

[0138] Figure 11b shows a plan view of the support block 1000. As shown, protrusions 1108 are arranged in a grid on an upper surface of the upper platform portion 1120 of the support block 1000.

[0139] Figure 11 c shows a view from the underside of the support block. As shown, recesses 1116 are arranged in a grid on an underside of the base portion of the support block 1000.

[0140] Figure 12 shows a perspective view of another implementation of a thermal energy7storage block 1200. This implementation facilitates faster manufacturing, in view of the simpler design. In particular, thermal radiation cavities are formed by an arrangement of a plurality of the blocks 1200 (as discussed below), instead of being formed in an individual block itself.

[0141] The block 1200 is formed in a generally parallelepiped, or cuboid, shape. A plurality of fluid flow slots 1202 extend in a first (horizontal) direction through the block 1200. and thereby define fluid flow pathways through the block 1200, in a similar manner to the fluid flow slots described above. The block 1200 is also provided with two chamfered edges 1218, which extend in a second (vertical) direction, perpendicular to the first direction. The chamfered edges 1218 are provided so that, in use, the block 1200 is configured to abut at least another of the blocks 1200 with the respective chamfered edges engaged to define a thermal radiation cavity.

[0142] The block 1200 also includes an integrated ledge 1210 configured to support heater elements, in a similar manner to the integrated ledges described above.

[0143] The chamfered edges 1218 are both provided on edges between a front face of the block 1200, into which the fluid flow slots 1202 are formed, and a side face 1220 of the block 1200, which may be a relatively wide face. The integrated ledge 1210 is provided in the opposing front face 1230 of the block 1200. into which the fluid flow slots are formed. The block 1200 is symmetric about a vertical plane which lies in the first and second directions, has its normal in a third direction perpendicular to the first and second directions, and which intersects the two front / end faces through their respective centers.

[0144] Figure 13a shows an assembly of blocks 1200 arranged on support slabs 1700. The support slab is described in further detail below. The blocks 1200 on the support slabs 1700 are arrangedin pairs of rows extending in the third direction (perpendicular to the first and second directions, and parallel to a surface of the slabs 1700), with gaps 1340 provided between the side faces 1220 of the blocks 1200 in a given row. The next row in the pair of rows is provided directly adjacent, and facing the first row, but offset in the third direction so as to align with the gaps 1340, and so that the chamfered edges engage. As a result, the gaps 1340 form thermal radiation cavities, bound by the front / end face of one block 1200 and the side walls of two other blocks 1200. Such radiation cavities 1340 are in fluid communication with the fluid flow slots 1202 which extend through the block 1200 in the first direction. Consequently, the thermal radiation cavities 1340 together with the fluid flow slots 1202 define fluid flow pathways through the assembly. A corresponding arrangement of blocks 1200 is also provided on the underside of the slabs 1700.

[0145] Pairs of rows of blocks 1200 on the slabs 1700 are arranged with a gap 1360 in between, and with their respective ledges 1210 facing one another. As a result, as depicted in Figure 13b, electrical heating elements 1382 may be positioned in the gaps 1360 between pairs of rows of blocks 1200, so as to be adjacent to the thermal radiation cavities 1340, to radiate thermal energy therein, and thereby store thermal energy7in the blocks 1200. The heating elements 1382 are held by a support structure 1380 which engages the integrated ledges 1210 in the blocks.

[0146] Figure 14 shows a perspective cross-sectional view of the arrangement depicted in Figure 12. The cross-section shows the fluid flow slots 1202, in the form of a channel, extending horizontally through the block 1200, and in fluid communication with the thermal radiation cavity 1340.

[0147] Figure 15 shows a plan view of the arrangement of blocks 1200 described above. Each of the gaps 1340, 1360 between the rows and the blocks are shown, and the engagement of the chamfered edges 1218 is also depicted.

[0148] Figure 16 shows a side elevation view of the arrangement of blocks 1200 described above. Blocks 1200 are provided in a staggered, or offset, arrangement both above and below the support slabs 1700.

[0149] Figure 17a shows a perspective view of a top side of support slab 1700 for use with the blocks 1200 as described above. The support slab 1700 has a plurality of recessed bays 1702 formed in an upper surface of the slab, the recessed bays each shaped and configured to retain a thermal energy storage block therein. The recessed bays are spaced apart and arranged in rows tospace apart the thermal energy storage blocks in the manner described above, with the appropriate gaps to form the thermal radiation cavities, and to provide space for the electrical heater elements. Two of the support slabs 1700 may abut in the manner depicted in Figures 13a-15, in order to create the pairs of rows of blocks 1200 described above.

[0150] In particular, the recessed bays 1702 are spaced apart and formed in rows, with the recessed bays 1702 in adjacent rows offset, such that, when blocks 1200 are disposed in respective bays 1702, the blocks 1200 form thermal radiation cavities therebetween, as described above. The recessed bays 1702 in adjacent rows are offset in a manner whereby a recessed bay in one row aligns with the center of a gap between consecutive recessed bays in the adjacent row. In this way, two of the support slabs 1700 can be combined to create the pairs of rows of blocks 1200 with thermal radiation cavities 1340 as described above.

[0151] Figure 17b a perspective view of an underside of support slab 1700 for use with the blocks 1200. In a corresponding manner to the top side, the bottom side of the support slab 1700 also includes recessed bays 1704. The bays 1704 correspond in their form and arrangement to the bays formed in the upper surface of the support slab 1700, but can be laterally offset, to create the staggered configuration shown in Figure 16. The support slab 1700 thereby enables a stacked arrangement of thermal energy storage blocks 1200 with the support slab between adjacent layers of the stack.

Claims

Claims1. A thermal energy' storage block comprising: one or more thermal radiation cavities; and a first set of fluid flow slots extending from, and in fluid communication with, a first thermal radiation cavity of the one or more thermal radiation cavities, such that the first set of fluid flow slots and the first thermal radiation cavity together define fluid flow pathways through the thermal energy storage block.

2. The thermal energy storage block of claim 1, wherein the thermal energy storage block is formed of a thermal energy' storage material, optionally comprising concrete.

3. The thermal energy storage block of any preceding claim, further comprising one or more interlock features on an external surface of the thermal energy storage block, wherein the one or more interlock features are configured to be inserted into engagement with one or more corresponding interlock features on another of said thermal energy' storage blocks, thereby enabling a stacking arrangement.

4. The thermal energy storage block of claim 3, wherein the interlock features comprise protrusions and / or recesses.

5. The thermal energy’ storage block of claim 4, wherein one of more of the protrusions are provided on an upper surface of the thermal energy storage block, and one or more of the recesses are provided on a lower surface of the thermal energy' storage block opposing the upper surface, and wherein the recesses are shaped to receive the protrusions.

6. The thermal energy storage block of claim 5. wherein the fluid flow slots are arranged in a first direction that is parallel to the upper surface and lower surface of the thermal energy storage block.

7. The thermal energy storage block of any preceding claim, further comprising: a second set of fluid flow slots extending from, and in fluid communication with, a second thermal radiation cavity7of the one or more thermal radiation cavities, such that thesecond set of fluid flow slots and the second thermal radiation cavity together define further fluid flow pathways through the thermal energy storage block.

8. The thermal energy storage block of any preceding claim, further comprising: a third set of fluid flow slots extending from, and in fluid communication with, a third thermal radiation canty of the one or more thermal radiation cavities, such that the third set of fluid flow slots and the third thermal radiation cavity together define further fluid flow pathways through the thermal energy storage block.

9. The thermal energy storage block of any preceding claim, wherein at least one side wall of the thermal energy storage block is configured to define a partial thermal radiation cavity', such that, in use, a further thermal radiation cavity is formed when the thermal energy' storage block is adjacent another of said thermal energy storage blocks.

10. The thermal energy storage block of claim 9, wherein the at least one side wall is recessed in order to define the partial radiation cavity.

11. The thermal energy storage block of claims 9 or 10, further comprising a fourth set of fluid flow slots extending from, and in fluid communication with, the partial thermal radiation cavity, such that the fourth set of fluid flow slots and the partial thermal radiation cavity together define additional fluid flow pathways through the thermal energy storage block.

12. The thermal energy storage block of any preceding claim, wherein diagonally opposite portions of the thermal energy storage block are recessed to define partial thermal radiation cavities, such that, in use, further thermal radiation cavities are formed when the thermal energy storage block is placed adjacent to others of said thermal energy storage blocks.

13. The thermal energy storage block of any preceding claim, wherein the thermal radiation cavities extend through a portion of the thermal energy storage block and the fluid flow slots extend through the remaining portion of the thermal energy storage block.

14. The thermal energy storage block of any preceding claim, wherein the thermal storage block is formed in a tessellating shape.

15. The thermal energy storage block of claim 14, wherein the tessellating shape comprises an asymmetric shape or an order two rotationally symmetric shape, optionally comprising a zig-zag shape or a wave-profile shape.

16. The thermal energy storage block of any preceding claim, wherein at least some of the fluid flow slots have a different sized and / or shaped opening than some others of the fluid flow slots.

17. The thermal energy storage block of any preceding claim, further comprising: an upper solid platform portion; and a lower solid base portion, wherein the fluid flow slots are arranged in a first direction that is parallel to the upper solid platform portion and the lower solid base portion, and wherein the thermal radiation cavity extends between the upper solid platform and the lower solid base portion in a second direction perpendicular to first direction.

18. The thermal energy storage block of claim 17. further comprising apertures formed in the upper solid platform portion and / or in the lower solid base portion to facilitate the passage of air therein.

19. The thermal energy storage block of any preceding claim, further comprising one or more integrated ledges for supporting heater elements adjacent to the one or more thermal radiation cavities.

20. A support block for the thermal energy storage block of claim 3, or any preceding claim when dependent thereon, the support block comprising: an upper platform portion; a base portion opposing the upper platform portion; a hollow channel between the upper platform portion and the base portion, the hollow channel defining a fluid flow pathway through the support block; andinterlock features provided on the upper platform and on the underside of the base portion of the support block and configured to engage the one or more interlock features of the thermal energy' storage block.

21. The support block of claim 20. further comprising: first and second opposing support walls extending between the upper platform portion and the base portion, wherein hollow channel is bound by the upper platform portion, the base portion, and the first and second opposing support walls.

22. The support block of claims 20 or 21 , wherein at least one side wall of the support block is recessed, such that, in use, one or more further hollow channels are formed when the support block is placed adjacent to another of said support blocks, thereby defining one or more further fluid flow pathways.

23. The support block of any of claims 20-22, wherein the interlock features comprise a plurality' of protrusions on the upper platform portion, and a plurality' of recesses shaped to receive the protrusions on the underside of the base portion.

24. The support block of claim 23 for the thermal energy storage block of claim 5 or any preceding claim dependent thereon, wherein the protrusions on the upper platform portion are configured to engage the recesses in the lower surface of the thermal energy’ storage block, such that the support block is configured to support said thermal energy' storage block thereon.

25. An assembly comprising the thermal energy storage block of any of claims 1-19 supported on the support block of any of claims 20-24.

26. An assembly comprising a plurality of stacked thermal energy' storage blocks according to claim 5 or any preceding claim when dependent thereon, wherein the thermal energy storage blocks in a given layer of the stack are laterally offset relative to the thermal energy storage blocks in the layer below, such that the recesses on the underside of a given block in the given layer are engaged by protrusions on a plurality of blocks in the layer below.

27. A thermal energy storage block formed in a generally parallelepiped shape, the block comprising: a plurality of fluid flow slots extending in a first direction through the block, the plurality of fluid flow slots defining fluid flow pathways through the block; and at least one chamfered edge in a second direction generally perpendicular to the first direction such that, in use, the block is configured to abut at least another of said blocks with the respective chamfered edges engaged to define a thermal radiation cavity.

28. The thermal energy storage block of claim 27, wherein the block comprises two chamfered edges in the second direction, such that, in use, the block is configured to abut at least two other of said blocks with the respective chamfered edges engaged to define a thermal radiation cavity between the blocks, the thermal radiation cavity in fluid communication with the fluid flow slots to define a fluid flow pathway therethrough.

29. The thermal energy storage block of claims 27 or 28, further comprising one or more integrated ledges configured to support one or more heater elements.

30. A support slab for the thermal energy storage block of any of claims 27-29, the support slab having a plurality of recessed bays formed in an upper surface thereof, the recessed bays each shaped and configured to retain said thermal energy' storage block therein, wherein the recessed bays are spaced apart and formed in rows, and wherein the recessed bays in adjacent rows are offset, such that, when said blocks are disposed in respective bays, the blocks form thermal radiation cavities therebetween.

31. The support slab of claim 30, wherein the recessed bays in adjacent rows are offset such that a recessed bay in one row aligns with the centre of a gap between consecutive recessed bays in the adjacent row.

32. The support slab of claims 30 or 31, further comprising a plurality of recessed bays formed in an underside surface, opposing the upper surface, said bays corresponding to the bays formed in the upper surface of the support slab, thereby, in use, enabling a stackedarrangement of thermal energy storage blocks with the support slab disposed between adj acent layers of the stack.

33. An assembly comprising a plurality of the thermal energy storage blocks of any of claims 27-29, each provided in a respective recessed bay on a support slab according to any of claims 30-32.

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