Conductive refractory brick system

Abstract

The thermal energy storage system includes a refractory brick gridwork and electrodes. The refractory brick gridwork includes one or more conductive refractory brick layers, each including a plurality of conductive-doped metal oxide refractory bricks with one or more air flow holes. The electrodes include one or more electrode refractory brick layers, each including a plurality of electrode refractory bricks. The refractory brick gridwork heats due to the application of power to the electrodes. Air flowing through the refractory brick gridwork can then be heated for use in heat-related applications (e.g., industrial applications, commercial applications, residential applications, transportation applications, etc.), some of which may be related to electricity production or for other purposes requiring heat unrelated to electricity production.

Description

[Technical field]

[0001]

[0001] One or more embodiments described herein relate to managing energy storage. [Background technology]

[0002]

[0002] Modern energy generation and distribution networks ("power grids") include many different sources of electrical power generation. Some generators (e.g., traditional generating equipment such as coal, oil, natural gas, and nuclear) can operate with relatively continuous output, while other sources, such as solar or wind power, can vary in their power generation capacity, for example, based on environmental factors. As more and more solar and wind generators come online to reduce greenhouse gas emissions, the expansion of the power storage capacity of the power grid may take into account the variability of output power. However, current battery technology has proven inadequate and is very costly to implement. Attempts have been made to use other types of energy storage systems, such as pumped hydroelectric storage. However, these other systems are location limited and not readily available or deployable. Summary of the Invention [Means for solving the problem]

[0003]

[0003] One or more embodiments described herein provide improved energy storage systems and methods that can be used for a variety of applications, including, of particular importance, storing power on a power grid.

[0004]

[0004] These and / or other embodiments provide energy storage systems and methods that control the storage of power to offset variability in the output of one or more power sources of a grid, including, but not limited to, variability in the output power of solar thermal generators, wind turbines, and other power sources subject to inconsistent operation due to environmental and / or other factors.

[0005] These and / or other embodiments provide improved energy storage systems and methods that are readily deployable in a variety of contexts.

[0006] These and / or other embodiments provide improved energy storage systems and methods that are economical to implement.

[0007]

[0007] According to one or more embodiments, a thermal energy storage system includes a refractory gridwork comprising one or more conductive refractory brick layers, each conductive refractory brick layer comprising a plurality of conductive doped metal oxide refractory bricks having one or more vents to allow air flow through the refractory gridwork, and a first electrode comprising one or more electrode refractory brick layers, each electrode refractory brick layer comprising a plurality of electrode refractory bricks, the first electrode configured to receive power from a power source, wherein the refractory gridwork is heated due to application of the received power. In such a configuration, air flowing through the refractory gridwork can be heated by the refractory gridwork to provide heat for a variety of uses, including, but not limited to, residential heat uses, industrial heat uses, commercial heat uses, transportation uses, and / or electricity production (which may occur in any or all of residential, industrial, commercial, and transportation environments). The concepts described herein may be utilized in both high temperature heat markets as well as electricity markets. Thus, after reading the description provided herein, one skilled in the art will understand that the thermal storage system described herein and other embodiments may provide heat to all types of heat users and heat-related applications (e.g., industrial applications, commercial applications, residential applications, transportation applications, etc.). It should be further understood that some of these applications may be related to electricity production, while other applications may be related to other purposes requiring heat that are unrelated to heat production. Thus, one or more embodiments may function as an effective replacement for batteries in some cases, while other embodiments may be used in various other contexts, such as to provide heat for virtually any purpose.

[0008]

[0008] In accordance with one or more embodiments, the apparatus includes a first electrode, a second electrode, and conductive refractory bricks, the conductive refractory bricks being arranged in a predetermined pattern between the first electrode and the second electrode, each of the conductive refractory bricks including a doped metal oxide material configured to generate heat based on an electric potential applied between the first electrode and the second electrode.

[0009] The foregoing and other objects, features and advantages will become apparent from the following more particular description of the present embodiments, as illustrated in the accompanying drawings in which like reference characters refer to like parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the embodiments. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a block diagram of an illustrative industrial system using a conductive refractory brick system, according to described embodiments. [Figure 2A]

[0011] 1 is a plot of material conductivity versus temperature for refractory bricks of various materials, according to described embodiments. [Figure 2B]

[0012] 1 is a plot of electron concentration versus temperature for a doped semiconducting refractory brick according to described embodiments. [Figure 2C]

[0013] 1 is a plot of electron concentration and resistivity versus temperature for a doped semiconducting refractory brick according to described embodiments. [Figure 2D]

[0014] FIG. 1 is a block diagram of an illustrative electrically heated thermal energy storage (E-TES) system using conductive refractory bricks, in accordance with described embodiments. [Diagram 3]

[0015] FIG. 1 is a diagram of an exemplary container system including an E-TES system, in accordance with described embodiments. [Figure 4]

[0016] FIG. 1 is a diagram of an illustrative E-TES system using conductive refractory bricks, in accordance with described embodiments. [Diagram 5]

[0017] FIG. 1 is a schematic diagram of an illustrative Y-configuration electrical connection of electrodes of an E-TES system, according to a described embodiment. [Figure 6]

[0018] FIG. 1 is a schematic diagram of an illustrative Y-configuration electrical connection of electrodes of an E-TES system, according to a described embodiment. [Figure 7A]

[0019] FIG. 1 illustrates an image of an illustrative refractory brick system, according to described embodiments. [Figure 7B]

[0020] FIG. 1 illustrates an image of an illustrative refractory brick system, according to described embodiments. [Figure 8A]

[0021] FIG. 1 is a perspective view of an exemplary electrode and conductive refractory brick layout for an E-TES system in a delta configuration, according to described embodiments. [Figure 8B]

[0022] FIG. 1 is a perspective view of an exemplary electrode and conductive refractory brick layout for an E-TES system in a Y configuration, according to described embodiments. [Figure 8C]

[0023] FIG. 13 is a perspective view of another illustrative electrode and conductive refractory brick layout for an E-TES system in a Y configuration, according to described embodiments. [Figure 9]

[0024] FIG. 1 is a block diagram of an exemplary energy distribution and storage grid using an E-TES system, in accordance with described embodiments. [Figure 10]

[0025] FIG. 1 is a block diagram of an exemplary concrete kiln system using an E-TES system, in accordance with described embodiments. [Figure 11]

[0026] FIG. 1 is a block diagram of an illustrative natural gas power system using an E-TES system, in accordance with described embodiments. [Figure 12]

[0027] FIG. 1 is a block diagram of an exemplary nuclear system using an E-TES system, in accordance with described embodiments. [Figure 13]

[0028] 1 is a pair of plots of resistivity versus temperature for a refractory brick using doped chromium oxide according to described embodiments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011]

[0029] One or more embodiments described herein provide systems and methods for implementing electrically heated thermal energy storage (E-TES). Such systems and methods may be useful for decarbonization for various applications, including, but not limited to, those related to power grids or industrial systems. As an increasing number of renewable energy generators are deployed in the power grid, abundant and inexpensive energy storage technologies are desired to cover the cycle in power generation, such as, for example, solar or wind energy generation. The embodiments of the E-TES described herein may meet these goals. Furthermore, these and / or other embodiments may be used in various industrial processes that generate and / or consume heat, such as furnaces, kilns, refineries, nuclear power plants, etc. As described herein, some embodiments of the E-TES may use electrically heated refractory bricks to store thermal energy for use as heat or conversion to electricity.

[0012]

[0030] FIG. 1 shows an embodiment of an exemplary deployment of an E-TES system using heated refractory bricks in a power grid or industrial system. As shown in FIG. 1, a heated refractory brick E-TES system 108 can receive an electrical input 104 to heat the refractory bricks and can also receive an air input 102. For example, the air input 102 can be “cold” air, ambient temperature air, exhaust from an industrial process, etc. The input air can be heated by the heated refractory bricks 108 and output as hot air 110. In some embodiments, the temperature of the output hot air 110 can be adjusted by a temperature adjustment section 114, which can include air provided by an air bypass 106 from the input air 102. For example, the temperature of the output air can be adjusted by providing cooler air (e.g., via the bypass 106) if the temperature of the heated refractory bricks 108 is higher than the temperature desired for the output hot air 110 to be provided to an output user 112, which can be, for example, a kiln or furnace. Alternatively, if the temperature of the heated refractory brick 108 is lower than the desired temperature for the output air 110, additional fuel, such as natural gas, can be provided via temperature adjustment section 114 to increase the temperature of the output hot air 110.

[0013]

[0031] In some embodiments, output user 112 may be a natural gas power cycle plant. According to one or more embodiments, a predetermined efficiency, for example, a round-trip electrical efficiency of 55-60% may be achieved. In other embodiments, output user 112 may be a nuclear power plant (e.g., a Gen IV reactor) and the E-TES system may achieve a round-trip electrical efficiency of, for example, 65-70%. In one embodiment, the E-TES system (e.g., refractory brick 108) may be located in close proximity to user 112.

[0014]

[0032] However, existing systems do not achieve a high enough temperature range and / or suffer from dramatically shortened life spans due to the required high temperatures. For example, existing heaters result in limited temperature ranges (e.g., heater Tpeak < refractory brick Tpeak), limited charge rates (e.g., limited ability to transport heat from the heater to the refractory brick due to the heater surface wattage loading and / or temperature gradients and thermal stresses in the refractory brick), and heater life spans that are dramatically shortened by high temperatures that can result in high replacement costs.

[0015]

[0033] Thus, one or more embodiments provide direct resistive heating of the refractory bricks 108. For example, one or more embodiments may electrically heat an insulated mass of refractory bricks to very high temperatures (e.g., from about 1000° C. to about 2000° C., however higher temperature ranges are possible). The heat stored within the refractory bricks 108 may be delivered as output air 110 by blowing air through passages within the hot refractory bricks to deliver the stored heat for industrial heat applications (e.g., kilns, furnaces, refineries) or electricity generation applications (e.g., power plants).

[0016]

[0034] The direct resistance heating (DRH) of the refractory brick 108 eliminates the shortcomings in commercially available heaters, with temperatures limited only by the properties of the refractory brick, allowing for higher temperature applications, increased energy density, and higher charging rates. Additionally, the refractory brick system eliminates the wattage load constraints of existing heaters, and designing the refractory brick to provide near uniform heat generation throughout the refractory brick system reduces stress on the system, which reduces repair costs and results in more reliable operation. Thus, according to one or more embodiments, a conductive brick is provided that can be mass-produced to form a stable, stackable electrical circuit for Joule heating that can be cycled daily within a predefined range (e.g., approximately 1000°C to approximately 1800°C, or another range) for long periods of time, e.g., years.

[0017]

[0035] The described embodiments provide a refractory brick made of a suitable material that has electrical conductivity to provide the desired heating characteristics. A gradual resistivity-temperature trend governed by carrier mobility can be a property of the refractory brick.

[0018]

[0036] FIG. 2A shows a plot providing examples of the conductivity of different materials versus temperature. The electrical conductivity of a material can be determined, for example, by Equation (1):

number

[0019]

[0037] Carrier mobility μ c can be estimated based on equation (2):

number

[0020]

[0038] As shown in Figure 2A, in metals, electrons have a continuum of allowable energies (e.g., Nc ≈ constant), so that heating is generally stable and any uneven heating is compensated for by lower conductivity in hotter regions and cooler regions having higher currents than warmer regions. Hence, electrical conductivity can be estimated as σ ∝ T-3 / 2.

[0021]

[0039] In a semiconducting refractory brick, the semiconducting intrinsic conductivity has a band gap between the conduction band and the valence band, so that the electrons are localized and cannot jump levels without thermal activation. Hence, the intrinsic conductivity is:

number

[0022]

[0040] In the case of semiconductor extrinsic conductivity, when a semiconductor is doped with an element that has one more or one less valence electron than the substituted element, electron donor or acceptor sites may be formed. The activation energy E associated with "donating" or "accepting" an electron may be less than the semiconductor band gap energy E. Thus, intrinsic conductivity is defined as:

number

[0023]

[0041] Thus, according to one or more embodiments, "metallic" behavior can be achieved in high temperature ceramics in highly oxidizing environments. Doping the semiconductor material to achieve a period of "depletion" before the exponential trend becomes dominant allows the formation of three distinct regions of conductivity, such as those shown in the plot in FIG. 2B: intrinsic, extrinsic (or "depleted"), and ionized (or "freeze-out"). As shown in FIG. 2B, in the extrinsic region, Nc(T) is constant, thus exhibiting metallic-like performance. As shown in FIG. 2C, in the unstable region, extrinsic carriers are activated (

number

number

[0024]

[0042] 2B and 2C show an example where the upper and lower temperature boundaries TU and TL can be selected by modifying the material and dopant levels, thus setting a desired temperature range of operation where the conductivity of the refractory brick material is approximately constant (e.g., depletion region). The temperatures TU and TL depend on the semiconductor bandgap energy Eg, which is the bandgap energy (eV) inherent to the refractory brick bulk material, Ea, which is the activation energy (eV) of the dopant sites due to the interaction between the dopant material and the bulk material, and the density (cm) of the dopant material being added. 3 In general, the depletion region shifts to higher temperatures as doping is increased.

[0025]

[0043] 2C shows a doped SiC ceramic heater, which is also a common refractory brick material, with a TL of approximately 800° C. and a TU of approximately 1600° C. Doped SiC is not suitable for E-TES because it typically oxidizes, which impedes the flow of electricity between the refractory bricks and ultimately destroys the bulk properties of the material.

[0026]

[0044] Thus, according to one or more embodiments, a refractory brick bulk material based on a metal oxide, such as chromium oxide (Cr2C3), can be selected with a given semiconductor bandgap energy Eg. A dopant material with a relatively low Ea can be used to dope Na to achieve a desired temperature range from TL to TU. The selection goal is to achieve a low TL (below about 700°C), a high TU (above about 1800°C), a large temperature range (e.g., depletion range above about 1000°C), and high Na (e.g., highly doped) such that impurities are negligible (above about 1020 / cm3).

[0027]

[0045] FIG. 2D illustrates an example in which a stable stackable semiconducting refractory brick may be provided according to one or more embodiments, which may achieve metallic conductivity behavior for use in an electrically heated thermal energy storage (E-TES) system. As shown in FIG. 2D, the E-TES system 200 may include a “top” electrode 202 and a “bottom” electrode 204. Between the electrodes 202 and 204 is a layer of refractory brick, shown as refractory brick layer 206. The refractory brick layer 206 includes a plurality of stackable refractory bricks 208, which may be at different levels, e.g., in an overlapping relationship with one another. In another embodiment, the refractory bricks 208 may all be at the same level. Because the refractory bricks 208 are freely stacked, the plurality of stackable refractory bricks 208 may form air passages 210 between adjacent pairs of individual refractory bricks (which also allows for thermal expansion of the refractory bricks). In general, the air flow can be in at least one predefined direction, an example of which is indicated by dashed line 212.

[0028]

[0046] FIG. 3 shows a diagram of an exemplary heat exchanger vessel that may be used to contain a refractory brick E-TES system as shown in FIG. 2D. As shown in FIG. 3, vessel system 300 may include an air inlet 310, a lower plenum 308, a body 312, an upper plenum 304, and a hot air outlet 302. Collectively, plenums 304 and 308 and body 312 may form vessel 314. Generally, vessel 314 may be an insulated steel vessel located in an industrial facility or power plant. In some embodiments with higher air pressure, vessel 314 may be prestressed concrete. As shown, vessel 314 may include a predefined pattern of refractory bricks (e.g., gridwork), shown as refractory bricks 306, and such as those shown with respect to FIG. 2D may be implemented.

[0029]

[0047] As shown, the lower plenum 308 is a hemispherical inlet for airflow into the vessel 314, and the upper plenum 304 is a hemispherical outlet for airflow through the vessel 314. Airflow is provided from the inlet 310, flows through the refractory bricks 306 as indicated by dashed arrow 316, and then exits through the hot air outlet 302. In some embodiments, the lower plenum 308 includes a support structure for the vessel 314 (e.g., corrosion resistant steel, ceramic archways, dome structures, etc.) to support the vessel 314 as a standing structure. Additionally, in some embodiments, the lower plenum 308 may be maintained at a lower temperature than the remainder of the vessel 314 by using an insulating layer between the lower plenum 308 and the refractory brick gridwork 306 and / or by using one or both of passive and active cooling. Although shown in FIG. 3 as being generally cylindrical, the vessel 314 has a particular size and shape that will vary based on its use and application.

[0030]

[0048] As described, the vessel 314 may have a large electrical input (e.g., as three-phase AC power or as DC power) and in one embodiment, the refractory gridwork 306 may be implemented to have three isolated conductive refractory brick sections in a predefined configuration. Examples include a delta configuration, a wye configuration, or another configuration. In one embodiment, the three-phase power may be provided by electrical feedthroughs into the refractory gridwork and / or conductive electrodes that can withstand a high temperature oxidizing environment.

[0031]

[0049] Figure 4 illustrates an embodiment of a refractory brick gridwork 306 that may be included within the heat exchanger vessel of Figure 3. As shown in Figure 4, the refractory brick gridwork 306 may include multiple layers or sections of chimney-type refractory brick gridwork having different conductivities and / or functions.

[0032]

[0050] As shown in FIG. 4, an illustrative embodiment may use three general types of refractory bricks: insulating refractory bricks 402, 410, 412, and 414, electrode refractory bricks 404 and 408, and conductive refractory bricks 406. The insulating refractory bricks are electrically insulating and may be implemented using a predefined combination of materials. An example combination is alumina / magnesia / silica. The electrode refractory bricks are highly doped (~ about 10 .mu.m) which provides high conductivity and low heat generation. 21 / cm 3 ) metal oxide refractory brick (e.g., electrode refractory brick does not require a low temperature coefficient of resistance). Conductive refractory brick is a carefully mixed and doped material that is approximately 10 times more resistive and has a low temperature coefficient of resistance than electrode refractory brick (~about 10 20 / cm 3 ) metal oxide refractory brick.

[0033]

[0051] 4, a top layer of insulating refractory brick, shown as top insulating layer 402, electrically insulates the top electrode 404 from the structure of the vessel 314 and provides thermal mass and weight for good electrical contact between the top electrode 404 and the conductive refractory brick gridwork 406. In some embodiments, the top electrode 404 may be comprised of multiple sections of electrode refractory brick, shown as electrode sections 404a-n. In some embodiments, there may be three electrode sections of the top electrode 404, for example, to isolate individual phases of a three-phase power input. Each of the electrode sections 404a-n may be separated by one or more sections of insulating refractory brick, shown as insulating sections 414. In other embodiments, a different number of sections may be included.

[0034]

[0052] The conductive refractory brick gridwork 406 may also include multiple sections of conductive refractory bricks, shown as conductive sections 406a-n, which in some embodiments may be generally aligned with and correspond to electrode sections 404a-n for three-phase power. The conductive refractory brick gridwork 406 is the location of heat generation and storage in the E-TES system. The bottom electrode 408 is also constructed of electrode refractory bricks. In embodiments using a wye configuration three-phase power, the bottom electrode 408 is a single section and forms the neutral of the contacts for the three-phase wye configuration, as shown in FIG. 4. In embodiments using a delta configuration three-phase power, the bottom electrode 408 may be separated into multiple conductive sections to transfer electricity through the gridwork 406 and provide an impedance load between the phases. The bottom insulating layer 410 is made of insulating refractory brick and electrically and thermally insulates the bottom electrode 408 from the vessel 314. In other embodiments, a different number of conductive sections may be included.

[0035]

[0053] FIG. 5 illustrates an embodiment of an E-TES system 500 that uses a wye-configured three-phase power that allows the vessel penetrations for the electrodes to be at the top of the vessel 314, for example, by introducing electricity only at the top electrode 404. As shown, a source 502 generates three-phase electricity, with a single phase provided to a corresponding one of the upper electrode sections 404a-c. As shown in FIG. 5, each electrode section 404a-c may have one or more electrical penetrations in the vessel 314, shown as electrical connections 504. The illustrative embodiment shown in FIG. 5 may include electrical connections 504 only at the top of the vessel 314. For example, in an embodiment having power connections only at the top of the vessel 314 at the upper electrode 404, maintenance or replacement of components may be easier by removing only the top insulating layer 402. Other embodiments may additionally or alternatively use connections at the bottom of the vessel 314, which may be more difficult to access for maintenance, but may benefit from lower temperatures due to airflow through the E-TES system. In some embodiments, the electrical penetration 504 can be temperature and / or pressure controlled, for example by an annular vessel sleeve, to maintain a reliable ceramic / metal interface between the electrical penetration 504 and the electrode refractory brick section 406.

[0036]

[0054] 6 shows an illustrative electrical schematic diagram of a wye-configured embodiment of an E-TES system 500. In this embodiment, each section of the upper electrode 404 corresponds to a given phase supplied from the generator 502, and the lower electrode 408 may be used to provide a neutral point, optionally having a neutral connection 602.

[0037]

[0055] As described herein, embodiments provide an electrically conductive refractory brick made of doped metal oxides that offers a high temperature operating range (approximately 1800° C.), is electrically conductive, electrically stable (exhibiting nearly constant resistivity above 400° C.), thermally cycleable over many cycles, physically stackable with low contact resistance (as low as 0.1 Ω-cm at 5 PSI), and inexpensive.

[0038]

[0056] 7A shows an illustrative embodiment of a refractory brick gridwork 700. The gridwork 700 may include multiple layers (or levels) of refractory bricks 702 stacked on top of one another, shown as layers 710a-n. As shown, each refractory brick 702 may be implemented as a chimney-type brick having one or more chimney vents 708 passing through the refractory brick along the axis of the refractory brick (e.g., vertically from bottom to top). For example, as shown, each refractory brick 702 includes seven chimney vents 708, each of which is generally hexagonal in cross-sectional shape. The overall shape of each refractory brick 702 is selected to be generally symmetrical to allow for easy stacking and placement within a gridwork including multiple refractory bricks, as well as ease of manufacture. For example, as shown in FIG. 7, the refractory bricks 702 may also be generally hexagonal in shape and may include one or more ridges 706 and / or teeth 704 around the outer edge or perimeter of the refractory brick. The outer ridges and teeth may facilitate placement of multiple refractory bricks into a gridwork and facilitate interlocking of the refractory bricks. Additionally, the shape of the refractory bricks 702 and the ridges 706 and teeth 704 may facilitate deployment of the refractory bricks 702 in different shaped containers (e.g., container 314 of FIG. 3) without modifying the refractory bricks. Similarly, one side (e.g., top) of each refractory brick 702 may include a recess 712 and the opposite side (e.g., bottom) may have a corresponding protrusion (not shown) to fit within the recess, further facilitating stacking and interlocking of the refractory bricks.

[0039]

[0057] 7B shows another illustrative embodiment of a refractory brick gridwork, shown as refractory brick gridwork 720. As shown, each refractory brick 722 can include one or more chimney vents 728. As shown, each chimney vent can be generally square in cross section and can pass through the refractory brick along the axis of the refractory brick (e.g., vertically from bottom to top). The edges of each refractory brick 722 can be beveled or rounded to facilitate placement within the gridwork and / or deployment within containers of different shapes, as shown as edges 724 and 726. Some embodiments can include one or more side notches 730 to facilitate interlocking of the refractory bricks.

[0040]

[0058] The refractory brick embodiment shown in Figures 7A and 7B may allow the bricks to expand and contract as temperatures change, without the need for any material between the refractory bricks that could expand and contract and / or be damaged by extreme temperatures; this deformability allows the conductive refractory brick to maintain a good electrical connection even as the material deforms over temperature changes.

[0041]

[0059] Thus, the described refractory bricks are made by mixing a bulk material in powder form (e.g., chromium oxide) with a desired amount of a dopant material (e.g., nickel oxide). In some embodiments, the dopant material can be approximately 2%-5% of the mixture. The mixture is then mechanically pressed into a brick having a desired size, shape, and form factor, and including one or more chimney vents to allow air flow through the refractory brick. The refractory brick is then temperature / pressure sintered into a brick.

[0042]

[0060] In the described embodiments, the refractory brick may be nickel-doped chromium oxide, magnesium-doped chromium oxide, lithium-doped nickel oxide, copper-doped nickel oxide, aluminum-doped zinc oxide, cerium-doped stabilized zirconium oxide, niobium-doped titanium oxide, or other high temperature metal oxides doped with metals of different valences, which may be mixed with electrically inactive oxides such as alumina, magnesia, or silica. For example, in some embodiments, some alumina (e.g., aluminum oxide) may be mixed with nickel-doped chromia (e.g., chromium oxide), which may make the refractory brick cheaper and / or stronger without significantly changing the electrical properties of the refractory brick.

[0043]

[0061] 8A shows an illustrative embodiment of a refractory brick system 800 that may be an implementation of the system shown in FIG. 4. As shown, the upper electrode 802 may include one or more insulating sections 822 such that the insulating sections 822 divide the upper electrode 802 into a plurality of conductive sections 820. Similarly, the refractory brick gridwork portion 804 may also include one or more insulating sections 818 such that the insulating sections 818 divide the refractory brick gridwork 804 into a plurality of conductive sections 816. The lower electrode 806 may also include one or more insulating sections 812 such that the insulating sections 812 divide the lower electrode 806 into a plurality of conductive sections 810. As described herein, the upper electrode 802, the lower electrode 806, and the refractory brick gridwork 804 may each include multiple layers of refractory brick, with the insulating and conductive sections of each layer overlapping and generally aligned with one another such that the multiple layers form a multi-layered overall. Thus, each of the upper electrode 802, the lower electrode 806, and the refractory brick gridwork 804 may have multiple multi-layer refractory brick electrical isolation portions.

[0044]

[0062] In some embodiments, the geometry of conductive portions 820, 816, and 810 may be arranged such that the various conductive portions overlap one another, thereby forming electrical connections and forming paths for electricity to be conducted through refractory brick system 800. For example, as shown in FIG. 8A , line 808 illustrates an example electrical path of system 800 based on the arranged overlap of conductive portions 820, 816, and 810.

[0045]

[0063] Thus, one or more embodiments provide an electrically conductive refractory brick that can form a stable and stackable conductive medium in air, and the manner in which the refractory bricks are stacked can form the desired electrical flow paths throughout the system 800. As described herein, the refractory brick gridwork 804 is the site of heat generation. In general, the refractory brick gridwork 804 and the upper electrode 802 can be divided into multiple (e.g., three) electrically isolated phase sections to receive each phase of three-phase power. Furthermore, each phase section can be further segmented to form a "serpentine" electrical path 808 to achieve a desired system resistivity and charge behavior, as well as to ensure passive charge stability of the system 800. For simplicity, the line 808 shows the electrical path for a single electrical phase of the system 800, and the electrical paths for the other phases can have a similar configuration.

[0046]

[0064] As shown, the conductive refractory bricks are separated by insulating refractory bricks to form a serpentine electrical path indicated by lines 808 through the top electrode 802, the refractory brick gridwork 804, and the bottom electrode 806. The top electrode 802 and the bottom electrode 806 are separated by the insulating refractory bricks in a different pattern than the refractory brick gridwork 804, but the patterns may overlap each other to connect vertical electrical paths as indicated by lines 808.

[0047]

[0065] In some embodiments, both the "beginning" and "end" of the electrical pathway 808 are at the top electrode 802, thus avoiding the need to provide any electrical feedthroughs at the bottom of the vessel, e.g., as described with respect to FIG. 5. However, as described herein, other embodiments may alternatively or additionally use electrical feedthroughs at the bottom of the vessel. For example, the checkerboard work pattern of the illustrative embodiments described herein (e.g., as shown in FIGS. 8A, 8B, and 8C) may be reversed if it is desired to have the power connections located at the bottom of the vessel rather than the top.

[0048]

[0066] As shown in FIG. 8A, the electrical system is operating in a delta configuration. The number of serpentine paths desired for the system determines the operating configuration, such that the electrical penetration is at the top of the system. When the number of serpentine paths is even, the system has a delta configuration, and when the number of serpentine paths is odd, the system has a wye configuration. FIG. 8A shows an illustrative "six-path delta configuration" system. Additionally, although generally described herein as using three-phase AC power, some embodiments may use DC power, for example, when powered by a DC power source such as a solar panel array or rectifier. As described above, electrical path 808 is a serpentine electrical path for a single phase of a three-phase system, and thus a three-phase system would use three separate electrical paths. In a DC system, the same serpentine configuration of electrical path 808 used in the delta configuration may be used, but the three electrical paths of the three-phase system would instead be connected in series between two nodes of the DC power source.

[0049]

[0067] According to one or more embodiments, the width of the insulating sections 822, 818, and 812 is a minimum of two refractory bricks to maintain isolation in a staggered pattern, although other embodiments may include wider insulating sections. As shown in FIG. 8A, the conductive regions 816 of the refractory brick gridwork 804 are sized (in some embodiments, cross sections in the range of 0.25 m to 1.5 m) so that electricity and heat are conducted quickly enough to avoid runaway conditions and to result in consistency in temperature throughout the refractory brick gridwork 804. In some embodiments, the various conductive regions 816 are approximately similar in size so that electrical flow is symmetric between the regions, resulting in a more consistent temperature distribution throughout the refractory brick gridwork 804. In some embodiments, the height of the refractory brick gridwork 804 (e.g., the conductive regions 816 and the insulating sections 818) is in the range of tens of meters (e.g., typically 20 to 40 m).

[0050]

[0068] 8B and 8C show illustrative embodiments of electrodes and conductive refractory brick layouts for an E-TES system in a Y configuration. For example, FIG. 8B shows an illustrative refractory brick system 801 using electrical paths 808 in a “three-pass” Y configuration. Similar to FIG. 8A, electrical paths 808 represent one of the electrical paths in a three-phase system. As described herein, in some embodiments, a given electrical path 808 corresponds to one of the phase legs of the three-phase system and may begin at a given one of the conductive regions 820 of the top electrode 802. Each electrical path 808 may terminate at a Y node 821, with electrical flow through the path 808 for one of the legs of the three-phase system flowing countercurrently through the electrical paths for the other legs of the three-phase system.

[0051]

[0069] 8B depicts each serpentine path 808 as having the same (or substantially similar) shape, this is not required by the present system. In one or more embodiments, electrical paths 808 may be used having the same (or substantially similar) flow area to avoid bottlenecks in the current flow where overheating may occur. As shown in FIGS. 8A and 8B, each layer 802, 804, and 806 of the refractory brick system may have a predetermined geometric shape (e.g., may be generally hexagonal) to facilitate fit within a vessel having a generally circular cross-sectional shape, for example, although other shapes and configurations are possible.

[0052]

[0070] FIG. 8C shows an illustrative refractory brick system 803 using layers 802, 804, and 806 having a generally square or rectangular cross-sectional shape, which may be advantageously used in vessels of the same cross-sectional shape. As shown in FIG. 8C, electrical paths 808 in a "three-pass" Y (Wye) configuration. As in FIG. 8A, electrical paths 808 represent one of the electrical paths in a three-phase system. As described herein, in some embodiments, a given electrical path 808 corresponds to one of the phase legs of the three-phase system and may begin in a given one of the conductive regions 820 of the upper electrode 802. Each electrical path 808 may terminate at a Y (Wye) node 821, with electrical flow through the path 808 for one of the legs of the three-phase system flowing countercurrently through the electrical path for the other leg of the three-phase system. Although each serpentine path 808 is shown in FIG. 8C as having the same (or substantially similar) shape, this is not required by the present system. Preferably, the described embodiments use electrical paths 808 that have the same (or substantially similar) surface area (not necessarily shape) so that the current flow is substantially the same in each path, thus avoiding higher resistance current flow bottlenecks where overheating could occur.

[0053]

[0071] In this manner, the E-TES refractory brick system as described according to one or more embodiments may achieve heating systems of various sizes, shapes, and temperatures up to a certain limit, for example, about 2000° C., or another limit in air. The refractory brick system may have a modular design in terms of shape and size, and thus may be adapted to various furnace or vessel shapes and sizes. Furthermore, the refractory brick system as described herein may achieve higher temperatures than other systems can achieve while operating with high stability over a longer heater life than other solutions, and at the same time be compatible with standard control systems.

[0054]

[0072] 9 shows an illustrative embodiment of an E-TES refractory brick system 912 in an example electrical distribution grid 900. As shown in FIG. 9, the E-TES system 912 can be used in conjunction with existing power generation and storage technologies (e.g., power generation equipment 902, heat generators 904, synthetic fuel system 906, power cycle system 908, and conventional electrical storage system 910) to store excess electricity as heat and provide the stored energy to electrical consumers 914 as electricity or to thermal consumers 916 as heat.

[0055]

[0073] FIG. 10 illustrates an embodiment of an E-TES refractory brick system as described herein for use in, for example, one or more cement kilns. As shown, the E-TES system may receive cool air from the cement plant's grate cooler and then supply electrically heated air to one or both of the rotary kiln and / or precalciner. This may result in significant carbon emission reductions for the cement plant and may also result in significant energy cost savings (renewable energy surplus). The reduction in flue gas usage may result in easier firing of the cement. Finally, the E-TES system is estimated to be very cost-effective for the cement plant, estimated to be approximately 5% of the total cement plant cost.

[0056]

[0074] FIG. 11 shows an embodiment of an E-TES system that may be used to act as a battery when coupled to a power plant, which may be, for example, a natural gas power plant, shown as plant 1100. As shown, the E-TES system 1106 may be provided with air from a compressor 1104. The E-TES system 1106 is electrically heated to provide hot air to a turbine 1108, which is provided to a heat recovery steam generator 1110 and stack 1112. The turbine provides power to the compressor 1104 and generator 1102. In one embodiment, natural gas may be injected to increase the heat to an even higher level. The system may achieve a predefined efficiency, for example, 55-65% round trip energy efficiency, or a different range of efficiencies.

[0057]

[0075] FIG. 12 illustrates an embodiment of an E-TES system that may be used with an air cycle system, e.g., a nuclear or solar thermal plant. As shown, a power plant system 1200 may include an E-TES system 1206 that receives cool air from one or more salt-air heaters 1204 and provides heated air to a turbine 1202, which may drive a generator 1208 and / or a heat recovery steam generator 1212. Zero carbon fuel may be added to the output of the E-TES system 1206 to raise or otherwise regulate the temperature to a desired range prior to input into the turbine. In one example implementation, this E-TES system may achieve a round-trip electrical efficiency of 65-70% or more, although different levels of efficiency may be obtained.

[0058]

[0076] 13 shows a first plot 1300 illustrating an example of resistance versus temperature for a doped chromium oxide refractory brick. Plot 1302 shows an expanded view of the area of ​​plot 1300 indicated by box 1304. As shown, the doped chromium oxide refractory brick achieves very low resistivity (<0.5 Ω-cm) that is nearly linear from 900-1500° C.

[0059]

[0077] Thus, according to one or more embodiments, an E-TES system is provided that may be useful for industrial and / or combined cycle plant applications operating at medium to high temperatures, such as steam systems, chemical plants, paper mills, etc., that use medium temperature heat (e.g., <500° C.), and for high temperature heat applications (e.g., about 800-2000° C.), such as steel, aluminum, cement, glass, and other high temperature industrial processes.

[0060]

[0078] After reading the description provided herein, it should therefore be understood that the thermal storage systems described herein, as well as other embodiments, can provide heat to all types of heat users and heat-related applications (e.g., industrial applications, commercial applications, residential applications, transportation applications, etc.). Some of these applications may be related to electricity production, while others may be related to other purposes requiring heat unrelated to heat production. Thus, one or more embodiments may function as an effective replacement for batteries in some cases, while other embodiments may be used in a variety of other contexts, such as to provide heat for virtually any purpose.

[0061]

[0079] As used herein, the term "metal oxide" generally refers to any polymer, molecule, or solid containing a metal or metalloid cation and an oxide anion. These include, but are not limited to, transition metal oxides, rare earth metal oxides, alkali metal oxides, and alkaline earth metal oxides. Structures include, but are not limited to, binary monooxides MO, dioxides MO2, sesquioxides M2O3, cuprite oxides M2O, and multimetal oxides, including, but not limited to, spinel-type structures MNO4, and perovskite MNO3, where M and N are different metal species.

[0062]

[0080] References herein to "one embodiment" or "an embodiment" mean that a particular feature, structure, or characteristic described in connection with that embodiment may be included in at least one embodiment of the claimed subject matter. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily mutually exclusive separate or alternative embodiments of other embodiments. The same applies to the term "implementation."

[0063]

[0081] To the extent that directional terms are used in the present specification and claims (e.g., above, below, upper, lower, parallel, vertical, etc.), these terms are merely intended to aid in describing various embodiments and are not intended to limit the scope of the claims in any way. Such terms do not require precision (e.g., strict perpendicularity or strict parallelism), but instead are intended to apply general tolerances and ranges. Similarly, unless expressly stated otherwise, each numerical value and range should be interpreted as being approximate, as if the words "about," "substantially," or "approximately" preceded the value or range value.

[0064]

[0082] Also, for purposes of this description, the terms "couple," "coupling," "coupled," "connect," "connecting," or "connected" refer to any manner in which energy is transferred between two or more elements.

[0065]

[0083] It should be understood that the steps of the exemplary methods set forth herein need not necessarily be performed in the order described. Similarly, additional steps may be included in such methods, and certain steps may be omitted or combined in ways consistent with various embodiments.

[0066]

[0084] It is further understood that various changes in the details, materials, and arrangements of parts described and illustrated to explain the nature of the described embodiments may be made by those skilled in the art without departing from the scope of the following claims.

Claims

1. a refractory brick layout comprising one or more conductive refractory brick layers, each conductive refractory brick layer comprising a plurality of conductive semiconductor doped metal oxide refractory bricks; one or more passages for permitting air flow through said refractory brick layout; a first electrode comprising one or more electrode refractory brick layers, each electrode refractory brick layer comprising a plurality of electrode refractory bricks, the first electrode being configured to receive power from a power source; Equipped with 1. A thermal energy storage system comprising: a first electrode refractory brick layer configured to electrically connect a first electrode refractory brick layout to a first electrode refractory brick layer;

2. a second electrode comprising one or more electrode refractory brick layers, each electrode refractory brick layer comprising a plurality of electrode refractory bricks; the refractory brick layout comprises a plurality of electrically isolated layout portions, the first electrode comprises a plurality of electrically isolated electrode portions; 2. The system of claim 1, wherein the second electrode is configured to be electrically coupled to two or more of the electrically isolated layout portions of the refractory brick layout to form an electrical transmission path through the refractory brick layout.

3. The system of claim 2 , wherein each of the plurality of electrically isolated electrode segments is configured to receive an isolated electrical phase from the power source.

4. 3. The system of claim 2, wherein the second electrode is configured to provide a neutral point for power provided as three phase power and the thermal energy storage system operates in a wye configuration.

5. 10. The system of claim 1, further comprising one or more insulation layers, said insulation layers comprising one or more insulating refractory brick layers, each insulating refractory brick layer comprising a plurality of non-conductive refractory bricks having one or more of said passages for permitting air flow through said insulating refractory bricks.

6. 10. The system of claim 1, wherein the conductive semiconductor doped metal oxide refractory brick comprises one of nickel doped chromium oxide, magnesium doped chromium oxide, lithium doped nickel oxide, copper doped nickel oxide, aluminum doped zinc oxide, cerium doped stabilized zirconium oxide, and niobium doped titanium oxide.

7. The conductive semiconductor doped metal oxide refractory brick is approximately 10 ２０ / cm ３ The system of claim 6 , wherein the doped concentration is

8. 10. The system of claim 1, wherein the electrode refractory brick comprises one of nickel doped chromium oxide, magnesium doped chromium oxide, lithium doped nickel oxide, copper doped nickel oxide, aluminum doped zinc oxide, cerium doped stabilized zirconium oxide, or niobium doped titanium oxide.

9. The electrode refractory brick is highly conductive and has a thickness of approximately 10 ２１ / cm ３ The system of claim 8 , wherein the semiconductor is highly doped with a concentration of

10. 6. The system of claim 5, wherein the non-conductive refractory brick comprises one or more of alumina, magnesia, or silica.

11. The system of claim 1 , wherein the refractory brick layout is heated to a temperature between 1000° C. and 2000° C.

12. the second electrode comprises a plurality of electrically isolated second electrode portions; 3. The system of claim 2, wherein the plurality of electrically isolated layout portions, the plurality of electrically isolated electrode portions, and the plurality of electrically isolated second electrode portions are configured to provide an electrical path through each electrically isolated layout portion.

13. 13. The system of claim 12, wherein the number of serpentines in each electrical path is an even number for the thermal energy storage system to operate in a three-phase delta configuration and the number of serpentines in each electrical path is an odd number for the thermal energy storage system to operate in a three-phase wye configuration.

14. The system of claim 8 , wherein the dopant mixture is approximately 2% to 5%.

15. 10. The system of claim 1, wherein the conductive semiconductive doped metal oxide refractory brick comprises a high temperature metal oxide doped with metals of different valences.

16. 20. The system of claim 15, wherein the conductive semiconductor doped metal oxide refractory brick further comprises an electrically inactive oxide.

17. 17. The system of claim 16, wherein the electrically inactive oxide comprises one of alumina, magnesia, or silica.

18. A first electrode; A second electrode; and Conductive refractory bricks and An apparatus comprising: the conductive refractory bricks are disposed in a predetermined pattern between the first electrode and the second electrode, each of the conductive refractory bricks comprising a semiconducting doped metal oxide material configured to generate heat based on an electrical potential applied between the first electrode and the second electrode.

19. the predetermined pattern includes a plurality of overlapping layers of the conductive refractory brick; 20. The apparatus of claim 18, wherein the electrically conductive refractory bricks are spaced apart to form air flow passages.

20. A first electrode; A second electrode; and Conductive refractory bricks and An apparatus comprising: the conductive refractory bricks are disposed in a predetermined pattern between the first electrode and the second electrode, each of the conductive refractory bricks including a semiconducting doped metal oxide material configured to generate heat based on an electrical potential applied between the first electrode and the second electrode; each of the conductive refractory bricks includes a dopant concentration corresponding to a temperature of heat that will be generated based on an electrical potential applied between the first electrode and the second electrode.

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