Energy storage system

Abstract

The thermal energy storage system described in the present disclosure can be used for long term storage of large amounts of thermal energy. In some cases, such systems receive electrical energy from renewable energy sources, such as solar panels or wind turbines. Using novel techniques, a thermal energy storage system converts electrical energy into thermal energy stored in a thermal material such as molten silicon, molten salt or any other material capable of storing significant amounts of heat. A thermal storage system incorporates excellent thermal insulation of a thermal storage tank containing a thermal material. The system is also configured to release thermal energy to a power generating steam turbine in an efficient manner using the described novel heat exchanger systems and techniques. The energy storage systems described herein have a higher overall actual efficiency than currently available energy storage systems.

Description

Technical Field

[0001] The present disclosure relates to novel energy storage systems for long-term energy storage. The present disclosure also relates to the integration of such energy storage systems with renewable energy sources (such as solar and wind energy), (optionally) flywheel energy storage systems, and steam pressure regulation systems for power generation steam turbines. Background Art

[0002] The energy received by the Earth from the sun is more than 10,000 times the energy consumed by all humans on Earth. Wind energy is a derivative of the energy from the sun. However, energy-poor societies rely mainly on energy from burning fossil fuels. There is strong international pressure to reduce the consumption of fossil fuels and switch to renewable energy sources such as solar or wind energy.

[0003] The cost of renewable energy is now roughly equal to or lower than the cost of energy produced by fossil fuels. However, a serious challenge of renewable energy is that the electricity generated by solar panels and wind turbines cannot be stored economically for long periods of time. This comes down to the need for long-term economic methods to store large amounts of energy from the sun.

[0004] There are a variety of different energy storage systems ("ESS") currently available. The main types of ESS are battery energy storage systems, flywheel energy storage systems, thermal energy storage systems ("HESS") (such as molten salt energy storage systems), compressed air energy storage systems, and gravity energy storage systems. Each of these ESS has unique advantages and disadvantages. However, as shown in the present disclosure, the novel integration of such storage systems together with novel technologies for insulated HESS solves problems that such stand-alone systems do not solve. Summary of the invention

[0005] The present disclosure describes a novel HESS for storing large amounts of thermal energy in thermal materials for a long period of time. In some cases, this HESS receives electrical energy from renewable energy sources such as solar panels or wind turbines. Using the novel technology described below, the HESS converts electrical energy into thermal energy stored in thermal materials (such as molten silicon or molten salt). The HESS described herein combines excellent insulation of the thermal energy storage tank containing the thermal material. Therefore, the thermal energy storage is efficient. The HESS is also constructed to release the thermal energy of the HESS to the power generation steam turbine in an efficient manner using the novel heat exchanger system and technology described below. Therefore, when the HESS described below is integrated with an energy source (e.g., a renewable energy source), a steam turbine generator system, and one or more flywheel energy storage systems (optional), the HESS can provide efficient energy reception, storage, and delivery. This type of HESS can greatly enhance the practical feasibility of renewable energy sources such as wind and solar energy.

[0006] In one aspect, the present disclosure relates to an energy storage system ("ESS") comprising a vacuum chamber and a thermal energy storage tank located within the vacuum chamber. The thermal energy storage tank comprises one or more walls, the one or more walls defining: (i) an enclosed interior space; and (ii) a plurality of open spaces extending within the enclosed interior space. The ESS also comprises: a thermal energy storage medium located within the enclosed interior space; a first heating device disposed in a first open space of the plurality of open spaces; and a radiation barrier disposed on an exterior surface of the one or more walls of the thermal energy storage tank. A first portion of the radiation barrier is disposed between: (a) the one or more walls defining the first open space and (b) the first heating device. The ESS also comprises a first actuator system coupled to the first portion of the radiation barrier. The first actuator system is operable to increase radiative heat transfer from the first heating device to the thermal energy storage medium by at least partially removing the first portion of the radiant barrier from between the one or more walls defining the first open space and the first heating device.

[0007] Such an ESS may optionally include one or more of the following features. The radiation barrier may include multiple sheets of material, the multiple sheets of material being spaced apart from the one or more walls, and the multiple sheets of material being spaced apart from each other. The ESS may also include a spacing member, the spacing member being disposed between at least some of the multiple sheets of material so that the multiple sheets of material are spaced apart from each other. In some embodiments, the spacing member includes multiple separate portions stacked on each other. The ESS may also include a heating reservoir configured to contain a fluid. The heating reservoir may be disposed in a second open space among the multiple open spaces. The ESS may also include a second actuator system, the second actuator system being coupled to a second portion of the radiation barrier, the second portion being disposed between: (i) the one or more walls defining the second open space and (ii) the heating reservoir. The second actuator system may be operable to increase radiative heat transfer from the thermal energy storage medium to the fluid contained in the heating reservoir by at least partially removing the second portion of the radiation barrier from between the one or more walls defining the second open space and the heating reservoir. The plurality of open spaces extending within the enclosed interior space may include at least two open spaces. In addition to the first heating device, the ESS may further include at least one additional heating device. Each additional heating device may be disposed in a corresponding open space among the plurality of open spaces. The horizontal cross-section of the thermal energy storage tank may have a circular or polygonal outer contour. The thermal energy storage medium may include salt or silicon. The first heating device may include a resistive heating element. The portion of the radiation barrier that is not disposed on the one or more walls defining the plurality of open spaces may be configured to be stationary relative to the thermal energy storage tank. The radiation barrier may include at least two sheets of material, the at least two sheets of material being spaced apart from the one or more walls, and the at least two sheets of material being spaced apart from each other.

[0008] In another aspect, the present disclosure relates to a method of storing energy. The method includes delivering electrical energy to one or more resistive heating devices, each of which is disposed in a corresponding open space of a plurality of open spaces defined by a thermal energy storage tank located within a vacuum chamber. The thermal energy storage tank also defines a closed interior space containing a thermal energy storage medium. The plurality of open spaces extend within the closed interior space. A radiation barrier is disposed on an exterior surface of the thermal energy storage tank. The method also includes at least partially moving one or more portions of the radiation barrier out of the corresponding open space to increase radiative heat transfer from the one or more resistive heating devices to the thermal energy storage medium.

[0009] This method may optionally include one or more of the following features. The method may also include: after delivering electrical energy to one or more resistive heating devices, moving the one or more portions of the radiation barrier back into the corresponding open space to reduce the radiant heat transfer away from the thermal energy storage medium. The method may also include delivering a fluid to a heating reservoir, which is disposed in an additional open space among the multiple open spaces defined by the thermal energy storage tank. The method may also include: at least partially moving an additional portion of the radiation barrier out of the additional open space to increase the radiant heat transfer from the thermal energy storage medium to the fluid. The method may also include: after heating the fluid by radiant heat transfer from the thermal energy storage medium, moving the additional portion of the radiation barrier back into the additional open space to reduce the radiant heat transfer away from the thermal energy storage medium.

[0010] Particular embodiments of the subject matter described herein can be implemented to achieve one or more of the following advantages. The HESS described herein maximizes thermal energy density per unit weight and per volume by making the most of the physical principles of vacuum insulation, which substantially eliminates heat losses due to conventional insulation systems. The HESS introduces novel heat exchange systems and techniques between the resistive heating device and the thermal energy storage medium and between the thermal energy storage medium and the heated reservoir of the working fluid of the heat engine. Such systems and techniques enhance the efficiency of the radiative heat transfer processes while such processes are taking place, and minimize heat losses and inefficiencies when these processes are completed.

[0011] Furthermore, the HESS described herein is advantageously designed to include structural support members that are optimized to reduce heat losses due to conduction. Furthermore, the HESS described herein includes highly efficient radiant barriers that virtually eliminate heat losses due to radiation. Thus, the efficiency and storage time of the HESS described herein are greatly improved compared to such systems known to date.

[0012] The performance of the HESS described herein does not degrade regardless of how frequently it is charged and discharged over many years (e.g., 20 years or more). In contrast, the performance of the widely used battery ESS gradually degrades each year and has a service life of only about 5 to 8 years on average. The HESS described herein is an alternative energy storage system that can replace certain current applications of battery-based energy storage systems (e.g., lithium battery energy storage systems) as a more economically viable and environmentally friendly large-scale and long-term system for storing energy from renewable energy sources.

[0013] The HESS described herein provides long-term and low-cost storage of renewable energy collected from solar panels, wind turbines, and / or other forms of renewable energy devices. In this context, "long-term" means a period of many days or weeks. "Low cost" means that the initial storage capital cost per kilowatt-hour (kWh) is significantly lower than the storage cost per kWh of modern commercially available flywheel energy storage systems (FESS) and other traditional ESS (such as lithium battery ESS widely used in the renewable energy industry). In addition, the overall efficiency of the HESS described herein increases as the size of the energy storage capacity increases.

[0014] Furthermore, the HESS described herein can provide large-scale storage of renewable energy without using environmentally and biologically harmful materials. In addition, the HESS occupies only a small area of ​​land.

[0015] The HESS described herein can also be used to reduce the heavy reliance of power-hungry societies on energy generated by burning fossil fuels.

[0016] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present disclosure belongs. In addition, the materials, methods, and examples of the embodiments described herein are illustrative only and are not intended to be limiting.

[0017] The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description herein. The scope and applicability of the HESS described herein are not limited by any specific numbers mentioned in this disclosure. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a perspective view of an example HESS according to some embodiments described herein.

[0019] Figure 2 Shows Figure 1 A HESS in which part of the vacuum chamber is transparent.

[0020] Figure 3 Shows Figure 1 A HESS with part of the vacuum chamber removed.

[0021] Figure 4 Shows Figure 1 An example radiant barrier for a HESS.

[0022] Figure 5 Shows Figure 1 Thermal energy storage tank of HESS.

[0023] Figure 6 Shows Figure 5 Exploded view of the thermal energy storage tank.

[0024] Figure 7 Shows Figure 5 A diagonal cross-section of a thermal energy storage tank.

[0025] Figure 8 The exploded perspective view shows Figure 5 Thermal storage tanks and Figure 4 parts of a radiation barrier.

[0026] Fig. 9 Another example thermal energy storage tank is shown.

[0027] Fig.10 Another example thermal energy storage tank is shown.

[0028] Fig.11 Shows that it is possible to Figure 1 Two example spacer components used together with the HESS.

[0029] Fig.12 Five Fig.11 of spacer members that interlock together in a stacked arrangement.

[0030] Fig.13 Shows that it is possible to Figure 1 Two other example spacer components used in conjunction with the HESS.

[0031] Fig.14 Five Fig.13 of spacer members that interlock together in a stacked arrangement.

[0032] Fig.15 It is shown Figure 1 Schematic diagram of the use of spacer members in a HESS.

[0033] Fig.16 It is shown Figure 1 Another schematic diagram of the use of the spacer member in the HESS, and along the Fig.15 The section plane 16 - 16 shown in FIG.

[0034] Fig.17 In the first configuration, Figure 1 The HESS's movable radiant barrier and actuator system.

[0035] Fig.18 In the second configuration, Fig.17 A movable radiation barrier and actuator system.

[0036] Fig.19 In the third configuration, Fig.17A movable radiation barrier and actuator system.

[0037] Fig. 20 In the fourth configuration, Fig.17 A movable radiation barrier and actuator system.

[0038] Fig.21 Shows Fig.17 Actuator system.

[0039] Fig. 22 Schematically depicts Fig.17 The arrangement.

[0040] Fig.23 Schematically depicts Fig.18 The arrangement.

[0041] Fig.24 Schematically depicts Fig.19 The arrangement.

[0042] Fig.25 Schematically depicts Fig. 20 The arrangement.

[0043] Fig.26 Shows Figure 1 Exploded view of a portion of a HESS comprising a radiant barrier, a heating device and a heating reservoir.

[0044] Fig. 27 Shows Fig.26 The components are arranged in an operating configuration and wherein the radiation barrier is transparent.

[0045] Fig.28 It is shown that the use Figure 1 Flowchart of the HESS method.

[0046] Like reference numerals designate corresponding parts throughout. DETAILED DESCRIPTION

[0047] The present disclosure describes a novel HESS for storing large amounts of thermal energy for long periods of time in a thermal material at a temperature range of, for example, about 200°C to 1,500°C. In some cases, such a HESS receives electrical energy from a renewable energy source, such as a solar panel or a wind turbine. Using the novel technology described below, the HESS converts the electrical energy into thermal energy, which is stored in a thermal material, such as molten silicon, molten salt, or any of a variety of materials capable of storing large amounts of heat within a thermal storage tank of the HESS. The HESS described herein introduces excellent insulation of the thermal storage tank containing the thermal material. Measures are included to minimize all forms of potential heat losses. Therefore, the thermal energy storage is highly efficient.

[0048] The HESS is also configured to release its thermal energy into the working fluid of the power generating steam turbine in an efficient manner using the novel heat exchanger system and technology described below. Therefore, when the HESS described below is integrated with an energy source (e.g., a renewable energy source), a steam turbine generator system, and a flywheel energy storage system ("FESS") (optional), the HESS is capable of providing efficient energy reception, storage, and delivery. This type of HESS can greatly enhance the practical feasibility of renewable energy sources such as wind and solar energy. For example, the HESS described herein can be advantageously integrated into a broader energy management system (e.g., the hybrid energy storage system described in U.S. patent application serial number 17 / 530,219 filed on November 18, 2021). In particular, the HESS described herein can be integrated into the disclosed hybrid energy storage system by replacing a molten salt energy storage system (e.g., reference number 120) with the HESS, which is a subsystem of the overall hybrid energy storage system described herein. Integrating the HESS described herein into such a hybrid energy storage system provides a novel system including a thermal energy storage system, a steam temperature regulation system, a steam turbine system, and a FESS as an optional fourth subsystem. Such a hybrid energy storage system provides long-term storage of a large amount of energy received from a solar energy source and / or a wind energy source, and provides long-term continuous delivery of electricity to users when the electricity generated by the solar energy source and / or the wind energy source is unavailable or interrupted due to reasons such as diurnal cycles, daily weather changes, long periods of adverse weather (such as continuous rain for several days in summer and snowstorms in winter), or sudden failures of the power grid of a city, building, campus, etc. Therefore, U.S. Patent Application Serial No. 17 / 530,219 is hereby incorporated by reference in its entirety and for all purposes.

[0049] Figure 1 An example thermal energy storage system 100 (or HESS 100) is depicted. The HESS 100 comprises a vacuum chamber 110. Electrical connections 102 and working fluid connections 104, which will be described in detail below, extend through the walls of the vacuum chamber 110. Furthermore, a plurality of actuator motors 152, which will be described in detail below, can be seen.

[0050] In this view of the HESS 100, substantially only the exterior wall surfaces of the vacuum chamber 110 are visible. The interior components of the HESS 100 are depicted in the following figures.

[0051] The HESS 100 includes a vacuum chamber 110 to enhance thermal insulation of the HESS 100. That is, the vacuum within the vacuum chamber 110 serves to reduce energy (heat) losses that would otherwise occur due to convection and conduction heat transfer.

[0052] HESS 100 can be scaled to substantially any desired size. For example, in some embodiments, HESS 100 has an outer diameter ranging from 5 feet to 20 feet, or 10 feet to 30 feet, or 20 feet to 40 feet, or 30 feet to 50 feet, or 40 feet to 60 feet, or more, without limitation.

[0053] Figure 2 A view of the HESS 100 is shown, wherein the lower portion of the vacuum chamber 110 is transparent. Figure 3 Shown is an exploded view of a HESS 100. In particular, the vacuum chamber 110 is shown in an exploded manner so that its internal contents are visible.

[0054] These views all show an assembly that includes a radiation barrier 120 surrounding a thermal storage tank 130 (not visible; see FIG. Figure 5 The vacuum of the vacuum chamber 110 permeates all spaces within the vacuum chamber 110. Therefore, all interior spaces within the radiation barrier 120 and the heat storage tank 130 are vacuum spaces, which almost eliminate the occurrence of convection and conduction heat transfer.

[0055] Figure 3 Also shown are portions of multiple actuator systems 150 including Figure 1 The structure and function of the actuator system 150 will be further described below.

[0056] Figure 4 The radiation barrier 120 is shown in more detail. Here it can be seen that the radiation barrier 120 is made up of multiple parts. In particular, the radiation barrier 120 includes a stationary part 122 and a plurality of movable parts 124a, 124b, 124c, 124d and 126.

[0057] The plurality of movable portions 124a-d and 126 are physically moved into and out of the stationary portion 122 at appropriate advantageous times by the plurality of actuator systems 150. Here, the plurality of movable portions 124a-d and 126 are shown in positions outside of the stationary portion 122. The importance of the mobility of the plurality of movable portions 124a-d and 126 will be further described below.

[0058] The radiation barrier 120 is made of multiple sheets of material spaced apart from each other (e.g., 2 mm or more). The sheets constituting the radiation barrier 120 are heat-resistant metal sheets, metal alloy sheets, or non-metal sheets, which have a smooth and shiny surface and have a low thermal radiation emissivity (e.g., an emissivity of about 0.2 or less). However, in some embodiments, the sheets constituting the radiation barrier 120 may have an emissivity higher than 0.2. In any case, the sheets constituting the radiation barrier 120 play a role in blocking, mitigating, or preventing radiant heat transfer.

[0059] The plurality of sheets constituting the radiation barrier 120 may include a number of spaced-apart sheets (or layers) ranging from 4 to 10 sheets, or 8 to 14 sheets, or 12 to 18 sheets, or 16 to 22 sheets, or 20 to 26 sheets, or 24 to 30 sheets, or 28 to 34 sheets, or 32 to 38 sheets, or 36 to 44 sheets, or 10 to 20 sheets, or 20 to 30 sheets, or 30 to 40 sheets, or 40 to 50 sheets, without limitation. In some embodiments, the stationary portion 122 and the plurality of movable portions 124a-d and 126 have the same number of spaced-apart sheets. In some embodiments, the stationary portion 122 and the plurality of movable portions 124a-d and 126 have different numbers of spaced-apart sheets.

[0060] In some embodiments, the plurality of sheets constituting the radiation barrier 120 may all be made of the same material. Alternatively, the plurality of sheets constituting the radiation barrier 120 may all be made of different materials (e.g., for different layers). The innermost layer of these sheets will directly or indirectly receive the strongest thermal radiation from the heat storage tank 130. In one example, when the thermal energy storage medium in the heat storage tank 130 is molten silicon, the highest temperature of the heat storage tank 130 will be about 1,500°C. Therefore, molybdenum may be a preferred choice of material for the innermost sheet constituting the radiation barrier 120. However, the temperature of the outermost sheet constituting the radiation barrier 120 including 20 or more sheets will be several hundred degrees Celsius. Therefore, stainless steel may be a preferred choice of material for the outermost sheet constituting the radiation barrier 120. In one example, when the thermal energy storage medium in the heat storage tank 130 is molten salt, the highest temperature of the heat storage tank 130 will be about 580°C. Therefore, for the heat storage tank 130 containing molten salt, stainless steel is a good alternative to the material of all sheets constituting the radiation barrier 120. However, the material of the sheet constituting the radiation barrier 120 is not limited to molybdenum or stainless steel.

[0061] Also refer to Figures 5 to 8 , the thermal energy storage tank 130 is located within the radiation barrier 120 (see in particular Figure 8 For greater visibility, Figure 8 The top of the thermal storage tank 130 or the radiation barrier 120 is not shown). The innermost layer of the radiation barrier 120 is spaced apart from the outer wall surface of the thermal storage tank 130 .

[0062] In this example, thermal storage tank 130 (and radiant barrier 120) are cylindrical. However, Fig. 9 and Fig.10 Two other possible shapes are shown. In particular, Fig. 9 The heat storage tank 130' is shown to have a rectangular cross-sectional shape, and Fig.10 A thermal storage tank 130" is shown having a hexagonal cross-sectional shape. Various other possible shapes of thermal storage tanks are also possible.

[0063] The thermal storage tank 130 may be constructed of materials such as, but not limited to, molybdenum, stainless steel, metal alloys, ceramic-coated materials, and other metal or ceramic combinations.

[0064] Still refer to Figures 5 to 8 , the thermal energy storage tank 130 includes one or more walls that define: (i) an enclosed interior space 132; and (ii) a plurality of open spaces 134a, 134b, 134c, 134d, and 136 extending within the enclosed interior space 132. In the depicted embodiment, the plurality of open spaces 134a-d and 136 extend from the top of the thermal energy storage tank 130 all the way to the bottom. Therefore, it can be said that the wall of the thermal energy storage tank 130 defining the plurality of open spaces 134a-d and 136 is like a tube or a through hole. In this example, the tube has a rectangular cross-sectional shape. However, any other type of cross-sectional shape may be utilized, such as a circle, a triangle, a polygon, etc. In addition, in a single embodiment of the thermal energy storage tank 130 (and the radiation barrier 120), a plurality of different types of shapes may be combined.

[0065] The enclosed interior space 132 contains a thermal energy storage medium 140 (not shown). The thermal energy storage medium 140 can be a material such as silicon, salt, or other material. When heated, for example, silicon or salt will melt within the enclosed interior space 132, thereby storing a high level of thermal energy.

[0066] In the depicted embodiment, the thermal storage tank 130 defines a total of five open spaces 134a-d and 136. It should be understood that this is merely an example and any number of open spaces may be included in various configurations of the thermal storage tank 130.

[0067] The plurality of open spaces 134a-d and 136 defined by the thermal storage tank 130 are shaped and sized to receive the plurality of movable portions 124a-d and 126 of the radiation barrier 120 therein. That is, the plurality of movable portions 124a-d and 126 of the radiation barrier 120 are extendable into (and retractable out of) the plurality of open spaces 134a-d and 136 defined by the thermal storage tank 130. The stationary portion 122 of the radiation barrier 120 surrounds the other exterior walls of the thermal storage tank 130 (i.e., except for the walls defining the plurality of open spaces 134a-d and 136). Thus, all exterior wall surfaces of the thermal storage tank 130 are covered by the radiation barrier 120. This arrangement advantageously minimizes radiant heat loss from the thermal storage tank 130. However, there are situations when it is desired to transfer heat to or from the energy storage tank 130 (e.g., such as when transferring thermal energy to the thermal energy storage medium 140, or when extracting thermal energy from the thermal energy storage medium 140). In such situations, and as further described below, some or all of the plurality of movable portions 124a-d and / or 126 of the radiant barrier 120 can be moved out of the plurality of open spaces 134a-d and 136 defined by the thermal energy storage tank 130.

[0068] refer to Fig.11 and Fig.12 As described above, the innermost layer of radiation barrier 120 is spaced apart from the outer wall surface of thermal storage tank 130. In addition, each layer of radiation barrier 120 is spaced apart from its adjacent layer. To achieve this physical separation (which facilitates achieving a high level of thermal insulation) while providing structural support for the layers of radiation barrier 120 and thermal storage tank 130, spacers 160 may be incorporated into HESS 100.

[0069] The example spacers 160 are rectangular members that nest and interlock together to create a mechanically strong stack (such as Fig.12 ). Fig.13 and Fig.14 An L-shaped spacer 160 ′ is shown, which is an alternative to the rectangular spacer 160 .

[0070] Although the use of the spacer 160 will result in some loss of thermal energy through conduction from the thermal energy storage tank 130 to the radiation barrier 120 and from the radiation barrier 120 to the vacuum chamber 110, the spacer 160 is specifically designed to minimize such losses. For example, the spacer 160 includes several small solid blocks that are interlocked with each other and are stacked vertically. The resistance to heat conduction on the minimized butt surfaces of the stacked spacers 160 is very high. The butt surfaces are ideally dry interfaces, where there is no wetting and fusion between adjacent spacers 160. The thermal conduction resistance on such an interface of two solid blocks is much higher than the thermal conduction resistance through the solid blocks themselves. Therefore, it is advantageous to use multiple spacers 160 stacked on each other. In addition, the solid material of the spacer 160 itself should be selected to have low thermal conductivity and should also have sufficient hardness.

[0071] A vertical stack of multiple thin solid spacers 160 made of a material such as zirconium oxide will have a very high thermal conduction resistance from one end of the stack to the other end of the stack. Zirconia (zirconium oxide) has a maximum use temperature of 2249°C. Its compressive strength is 5200Mpa, and its low thermal conductivity is 2.7W / mK. However, the material of the solid spacer 160 used for this purpose is not limited to zirconium oxide.

[0072] The main contributor to the very high thermal conductivity impedance of the spacer 160 stack comes from the high thermal conductivity impedance at each of the butt contact surfaces of adjacent spacers 160 in the stack. This is why it is desirable that many solid spacers 160 (e.g., five or more) should be stacked vertically. In addition, this is why the surface area of ​​the butt contact surfaces should be minimized. A vertical stack of many such solid spacers 160 should be used as one of many support columns that support and hold the weight of the thermal storage tank 130 and the plurality of sheets of the radiation barrier 120 (e.g., the stationary portion 122 of the radiation barrier 120).

[0073] Fig.15 A HESS 100 is schematically depicted, wherein its thermal storage tank 130 contains a thermal storage medium 140, which is surrounded by a radiation barrier 120 (particularly a stationary portion 122 of the radiation barrier 120), which in turn is located inside a vacuum chamber 110. Also depicted are multiple stacks of spacers 160. As shown, the spacers 160 are used to provide vertical support and physical rigidity to the structure of the HESS 100.

[0074] In the depicted illustrative example, a stack of spacers 160 is located between an inner wall surface of vacuum chamber 110 and an outermost layer of radiation barrier 120. Additional stacks of spacers 160 are located between adjacent layers of radiation barrier 120. Furthermore, a stack of spacers 160 is also located between an innermost layer of radiation barrier 120 and an outer wall surface of thermal storage tank 130.

[0075] Fig.16 Another schematic diagram of a stack using spacers 160 in a HESS 100 is provided. Here, a top view of the HESS 100 shows a thermal storage tank 130 containing a thermal storage medium 140 surrounded by a radiant barrier 120 (particularly a stationary portion 122 of the radiant barrier 120).

[0076] In the depicted illustrative example, the stack of spacers 160 is arranged in two radial groupings (an inner radial grouping and an outer radial grouping). This arrangement of multiple stacks of spacers 160 can be utilized to provide vertical support and physical rigidity to the structure of the HESS 100. In addition, note that Figure 8 As shown in FIG. 1 , in some embodiments, the inner wall of the thermal storage tank 130 may include vertical beams 138 to provide additional rigidity to the wall of the thermal storage tank 130 .

[0077] Fig.16 Also shown are the plurality of movable portions 124a-d and 126 of the radiation barrier 120, which are depicted within the plurality of open spaces 134a-d and 136 defined by the thermal energy storage tank 130. Figures 17 to 25 Movement of the plurality of movable portions 124a - d and 126 of the radiation barrier 120 is described.

[0078] Fig.17 An example actuator system 150 is shown coupled to an example movable portion 124 of the radiation barrier 120. In the depicted arrangement, the movable portion 124 of the radiation barrier 120 is configured in its fully deployed arrangement. That is, in the depicted arrangement, the movable portion 124 is configured to be completely located within the corresponding open space of the movable portion 124 of the thermal energy storage tank 130 (not shown here to enhance the visibility of the movable portion 124). The fully deployed configuration is also Fig. 22 As schematically shown in Fig. 22 1 shows a cross-sectional view of an assembly including: a thermal storage tank 130 containing a thermal storage medium 140; a stationary portion 122 of a radiation barrier 120; a movable portion 124 of the radiation barrier 120; and a representative thermal member 170. The thermal member 170 is described below with reference to Fig.26 and Fig. 27 A representative of the heating device or heating reservoir described further.

[0079] like Fig. 22 As shown in FIG, in the fully deployed configuration, all of the sheets of movable portion 124 of radiant barrier 120 are positioned to block radiant heat transfer between thermal storage tank 130 and thermal member 170. In this illustrative example, there are nine individual sheets that make up stationary portion 122 and movable portion 124 of radiant barrier 120. This is merely an example. In some embodiments, more than nine or fewer than nine individual sheets may make up stationary portion 122 and movable portion 124 of radiant barrier 120.

[0080] Fig. 22 120. An example manner can also be seen in which the sheets of the stationary portion 122 and the movable portion 124 of the radiation barrier 120 can abut against one another. In particular, in the depicted embodiment, the lower edge portions of the sheets of the movable portion 124 overlap the vertically extending edge portions of the sheets of the stationary portion 122. In addition, the upper edge portions of the sheets of the movable portion 124 extend horizontally into close alignment (almost contact) with the edge portions of the horizontally extending sheets of the stationary portion 122. These types of close or overlapping interfaces between the sheets of the stationary portion 122 and the movable portion 124 of the radiation barrier 120 are specifically designed to block radiative heat transfer through the interface.

[0081] refer to Fig.18 The configuration of the movable portion 124 of the radiation barrier 120 has now been adjusted (with respect to the movable portion 124) by lifting some of the pieces of the movable portion 124 upward from their previous positions in which they blocked radiation between the thermal energy storage tank 130 and the thermal member 170. Fig.17 This is also schematically depicted in Fig.23 In this example, a grouping of three of the nine sheets of movable portion 124 have been moved upward from their previous position where they blocked radiation between thermal storage tank 130 and thermal member 170. Therefore, it can be imagined that the heat transfer impedance between thermal storage tank 130 and thermal member 170 provided by movable portion 124 of radiation barrier 120 has now been adjusted to a lower impedance.

[0082] The upward movement of the three pieces of the movable portion 124 can be caused by operation of the actuator system 150. An example actuator system 150 will now be described in more detail.

[0083] refer to Fig.21, an example actuator system 150 is depicted separately so that its components are more easily observable. The actuator system 150 includes a plurality of actuator motors 152 (e.g., DC servo motors, stepper motors, etc.), each of which drives one or more pinions 154, each of which meshes with a rack 156 attached to a vertical plate 158. The vertical plates 158 are each attached to one or more sheets of the movable portion 124 of the radiation barrier 120. In this non-limiting example, the vertical plates 158 are each attached to a grouping of three sheets of the movable portion 124 of the radiation barrier 120. Any number of sheets may be grouped, or the actuator system 150 may be capable of moving the sheets individually. In any case, when the actuator motor 152 is activated, the corresponding vertical plate 158 will be driven up or down, and the associated sheet of the movable portion 124 will also be driven up or down.

[0084] In the depicted embodiment, the matched pair of actuator motors 152 are activated simultaneously, causing two vertical plates 158 (one on each side of the grouping of sheets of the movable portion 124) to move synchronously. It should be understood that this type of actuator system 150 is just one example, and other types of actuator systems (e.g., cable and winch systems, linear actuator systems, etc.) may also be used.

[0085] Still reference Fig.18 , it can be seen that the two vertical plates 158 have now been driven upwards and are extending well above the level of the actuator motor 152. Those vertical plates 158 are housed within the vacuum chamber 110 and are housed in an upper auxiliary chamber portion 110' of the vacuum chamber 110 (eg, Figure 1 Best seen in ).

[0086] See also Fig.19 In the depicted configuration, another pair of actuator motors 152 has been activated to raise a second grouping of three pieces of the movable portion 124 of the radiation barrier 120. This configuration is also Fig.24 It can be seen that now, in this example, six sheets of the movable portion 124 have been removed to no longer block the radiative heat transfer between the thermal storage tank 130 and the thermal member 170, and only three sheets of the movable portion 124 remain. Therefore, the radiative heat transfer impedance between the thermal storage tank 130 and the thermal member 170 is now further reduced (as compared to Fig.18 and Fig.23 In some scenarios, this arrangement can be advantageously used to regulate the amount of heat transfer between the thermal energy storage tank 130 and the thermal member 170.

[0087] See also Fig. 20In the depicted configuration, a further pair of actuator motors 152 has been activated to raise a third grouping of three pieces of the movable portion 124 of the radiation barrier 120. This configuration is also Fig.25 170. It can be seen that now, in this example, all nine sheets of movable portion 124 have been removed from blocking radiative heat transfer between thermal storage tank 130 and thermal member 170, and there are no remaining sheets of movable portion 124. Therefore, the radiative heat transfer impedance between thermal storage tank 130 and thermal member 170 is now eliminated. In some scenarios, this arrangement can be used advantageously to maximize the amount of heat transfer between thermal storage tank 130 and thermal member 170.

[0088] Fig.26 An exploded view of a multi-piece radiation barrier 120 (with its movable portions 124a-d and 126 and stationary portion 122) is shown, covering all exterior wall surfaces of a thermal energy storage tank 130 (not visible). Also shown are four (4) heating devices 180a-d and a heating reservoir 190 as an example. Figure 1 Correspondingly, the heating devices 180 a - d have electrical connections 102 and the heating reservoir 190 has a working fluid connection 104 .

[0089] Also refer to Fig. 27 (wherein the radiation barrier 120 and the thermal energy storage tank 130 are transparent), each of the four heating devices 180a-d is disposed within the boundaries of a corresponding one of the movable portions 124a-d of the radiation barrier 120, and the heating reservoir 190 is disposed within the boundaries of the movable portion 126 of the radiation barrier 120. It should be understood that this arrangement is purely exemplary. That is, the HESS 100 may include various other arrangements and / or numbers of heating devices and / or heating reservoirs, which are also contemplated within the scope of the present disclosure.

[0090] Fig.28 A method of using a HESS, such as the HESS 100 described herein, is shown. At step 210, the HESS receives electricity generated by a renewable energy source, such as a solar panel or a wind turbine. At step 220, one or more heating devices of the HESS are powered using the electricity from the renewable energy source (e.g., the electricity received from the renewable energy source powers one or more heating devices 180a-d as described above).

[0091] At step 230, one or more first portions of the movable radiant barrier of the HESS are moved from the first configuration to the second configuration to increase radiant heat transfer from the powered heating device to the thermal energy storage medium contained within the thermal energy storage tank of the HESS. For example, in the context of the HESS 100 described herein, one or more movable portions 124a-d of the radiant barrier 120 are moved (upwardly) out of the way and no longer block radiant heat transfer from the powered heating device 180a-d to the thermal energy storage medium 140 contained within the thermal energy storage tank 130.

[0092] At step 240 , the previously powered-on heating device is powered-off.

[0093] At step 250, after de-energizing the previously energized heating device, the one or more first portions of the movable radiant barrier of the HESS are moved from the second configuration back to the first configuration to reduce radiant heat transfer away from the thermal energy storage medium contained within the thermal energy storage tank of the HESS. For example, in the context of the HESS 100 described herein, the one or more movable portions 124a-d of the radiant barrier 120 are moved downward to block radiant heat transfer away from the thermal energy storage medium 140 contained within the thermal energy storage tank 130.

[0094] At step 260, one or more second portions of the movable radiant barrier are moved from the first configuration to the second configuration to increase radiant heat transfer from the thermal energy storage medium to the working fluid in the heating reservoir. For example, in the context of the HESS 100 described herein, the movable portion 126 of the radiant barrier 120 is moved (upward) away and no longer blocks radiant heat transfer from the thermal energy storage medium 140 contained within the thermal energy storage tank 130 and the working fluid in the heating reservoir 190.

[0095] In step 270, the working fluid is conveyed through the heating reservoir 190 (where the working fluid is heated) and then conveyed to the steam turbine, which is coupled to drive a generator. This process can generate electricity that can be sent to users when the electricity output from renewable energy sources is insufficient to meet the needs of users.

[0096] In step 280, the one or more second portions of the movable radiant barrier are moved from the second configuration to the first configuration to reduce radiant heat transfer away from the thermal energy storage medium. For example, in the context of the HESS 100 described herein, the movable portion 126 of the radiant barrier 120 is moved downward to block radiant heat transfer away from the thermal energy storage medium 140 contained within the thermal energy storage tank 130.

[0097] Additional features and description

[0098] The HESS as described herein is a new energy storage system with excellent insulation that converts electrical energy from renewable energy sources such as solar and wind energy into thermal energy of thermal materials (such as hot / molten silicon or hot / molten salt) for long-term storage of thermal energy with the help of a carefully designed insulation system in a vacuum chamber.

[0099] The HESS as described herein can be considered to include four major components: (i) a thermal energy storage medium contained in a heat-resistant thermal energy storage tank, which is made of tungsten or molybdenum, stainless steel or other heat-resistant materials with suitable physical properties; (ii) a first heat exchange system that transfers the thermal energy of the thermal energy storage medium to the working fluid of the heat engine by non-contact radiative heat transfer from the thermal energy storage tank to the working fluid in the heating reservoir; (iii) a second heat exchange system that transfers heat generated by an ohmic heating device (resistive heating device) powered by electricity from a renewable energy source (e.g., solar panels or wind turbines) to the thermal energy storage tank by non-contact radiative heat transfer from the ohmic heating unit to the thermal energy storage tank; and (iv) a support structure system that supports the weight of the thermal energy storage tank and the multi-layer radiation barrier shielding sheet that encloses the thermal energy storage tank, the two heat exchange systems and other auxiliary components of the HESS. A unique and novel feature of the support structure of the HESS is that it will significantly minimize the inevitable loss of thermal energy from the thermal energy storage tank due to heat conduction through the material-to-material direct contact of the support structure. The HESS described herein can also be synergistically integrated into a hybrid energy storage system that can include a heat engine (with its steam turbine and generator system) and an optional FESS (flywheel energy storage system).

[0100] The salt stored in a conventional molten salt ESS is heated by ohmic heating units powered by electricity through direct contact between these ohmic heating units and the molten salt or containers of molten salt. Similarly, conventionally, heat exchangers between hot or molten salt and the working fluid of a heat engine such as a steam turbine are heated by the molten salt through direct contact between the molten salt and the heat exchange pipes carrying steam from and to the steam turbine. The materials used for the heat exchangers are good thermal conductors, so there are significant thermal energy losses in the conduction of heat through the materials of the heat exchangers.

[0101] Another novel feature of the HESS described herein is that heat exchange between the thermal energy storage tank and an ohmic heating unit powered by electricity from renewable energy sources; and heat exchange between the thermal energy storage tank and the working fluid of a heat engine capable of generating electricity is achieved by contactless radiative heat transfer in a vacuum between the ohmic heating unit powered by electricity from renewable energy sources and the thermal energy storage tank, and between the thermal energy storage tank and a heating reservoir containing a working fluid of a heat engine capable of generating electricity.

[0102] Additional key features of the HESS described herein include: its excellent insulation of the thermal storage tank; non-contact heat transfer between key components; built-in controllability of the rate of heat exchange between key components; and a unique and novel support structure that supports and maintains the structural integrity of the thermal storage tank with minimal heat loss through conduction through physical contact of the support structure with the thermal storage tank and the radiation shielding sheets of the radiation barrier.

[0103] The shape of the thermal energy storage tank of the HESS described in this article is not a very simple shape in topology. The reason for this not-so-simple topology of the shape of the thermal energy storage tank is to minimize the heat loss through thermal radiation during the process of heat exchange between the thermal energy storage tank and the ohmic heating unit and between the thermal energy storage tank and the heating storage. The space where the transfer of thermal radiation between the thermal energy storage tank and the ohmic heating occurs is the narrow confined space of the through-hole defined by the thermal energy storage tank. Therefore, during the energy exchange process between the thermal energy storage tank and the ohmic heating unit, almost no energy is lost to the open space outside the thermal energy storage tank. In other words, there is no thermal radiation "leaking" to the outside open space. This is why the thermal energy storage tank has a beneficial reason for the through-hole. This is also the reason why the heating storage for the working fluid of the heat engine is located in the through-hole of the thermal energy storage tank. These are the reasons why the 3D shape of the thermal energy storage tank is very different from the 3D shape of the traditional container of the molten salt used for energy storage in topology.

[0104] Several sheets of radiation barriers "shield" the radiative heat transfer from the ohmic heating unit to the thermal storage tank in a vacuum. By controlling the number of sheets of the radiation barrier located between the ohmic heating unit and the thermal storage tank, the heat transfer rate from the ohmic heating unit to the thermal storage tank can be adjusted or controlled. Similarly, by controlling the number of sheets of the radiation barrier located between the thermal storage tank and the heating reservoir, the heat transfer rate from the thermal storage tank to the working fluid heating reservoir can be controlled or adjusted.

[0105] A novel feature of the HESS described herein is that the number of sheets of the radiation barrier located between the thermal energy storage tank and the heating device (ohmic heating unit) and / or the working fluid heating reservoir can be easily changed / controlled during operation of the HESS. In this way, the rate of heat transfer by radiation heat transfer between the thermal energy storage tank and the ohmic heating unit or between the thermal energy storage tank and the working fluid heating reservoir can be advantageously adjusted or controlled (automatically or manually) during operation of the HESS described herein. For example, when the temperature of the thermal energy storage tank is too high, these features can be employed to avoid overheating of the working fluid as the working fluid passes through the heating reservoir. For example, in the case of molten salt, 700°C may be too high. In the case of molten silicon, 1,800°C may be too high. When the temperature of the thermal energy storage tank is too high, most of the sheets of the tube of the movable sheet of the radiation barrier should remain in its through hole to weaken the heat transfer from the thermal energy storage tank to the heating reservoir to avoid overheating of the working fluid. When the temperature of the thermal energy storage tank is too low, most or all of the sheets of the tubes of the movable sheets of the radiation barrier should be raised to increase the heat transfer from the thermal energy storage tank to the working fluid in the heating reservoir to avoid insufficient heating of the working fluid. When the HESS itself is idle, in other words, when there is no need to heat the working fluid, all the sheets of the movable sheets of the radiation barrier should remain deployed in the through-holes of the thermal energy storage tank so as to minimize the loss of thermal energy from the thermal energy storage tank via thermal radiation. This feature can also be used to avoid excessive heating of the thermal energy storage tank by the ohmic heating unit. Similarly, when there is no need to heat the thermal energy storage tank by the ohmic heating unit, all the sheets of the movable sheets of the radiation barrier that enclose the ohmic heating unit will remain in their through-holes to minimize any loss of thermal energy of the thermal energy storage tank.

[0106] Although this specification contains many specific implementation details, these details should not be interpreted as limitations on the scope of any invention or content that may be claimed, but should be interpreted as descriptions of features that may be specific to a particular embodiment of a particular invention. Certain features described in this specification in the context of separate embodiments can also be implemented in combination in a single embodiment. On the contrary, the various features described in the context of a single embodiment can also be implemented separately in multiple embodiments or in any suitable sub-combination. In addition, although features may be described herein as working in certain combinations and even initially claimed as such, in some cases, one or more features from the claimed combination can be cut out from the combination, and the claimed combination can be directed to a sub-combination or a variant of the sub-combination.

[0107] Similarly, although the operations are depicted in a particular order in the figures, this should not be understood as requiring that the operations be performed in the particular order shown or in a sequential order; or that all of the operations shown be performed to achieve the desired results. In some cases, multitasking and parallel processing may be advantageous. In addition, the separation of various modules and components in the embodiments described herein should not be understood as requiring such separation in all embodiments, and it should be understood that the components and systems can generally be integrated together in a single product or packaged into multiple products.

[0108] Specific embodiments of the subject matter have been described. Other embodiments are within the scope of the following claims. For example, the actions recited in the claims can be performed in a different order and still achieve the desired results. As an example, the processes depicted in the accompanying drawings do not necessarily require the particular order shown or sequential order to achieve the desired results. In some implementations, multitasking and parallel processing may be advantageous.

Claims

1. An energy storage system, comprising: Vacuum chamber; A thermal energy storage tank, the thermal energy storage tank being located within the vacuum chamber, the thermal energy storage tank comprising one or more walls, the one or more walls defining: (i) a closed interior space and (ii) a plurality of open spaces extending within the closed interior space; a thermal energy storage medium, the thermal energy storage medium being located within the enclosed interior space; a first heating device disposed in a first open space among the plurality of open spaces; a radiant barrier disposed on an exterior surface of the one or more walls of the thermal energy storage tank, wherein a first portion of the radiant barrier is disposed between: (a) the one or more walls defining the first open space and (b) the first heating device; as well as a first actuator system coupled to the first portion of the radiation barrier, Wherein the first actuator system is operable to increase radiative heat transfer from the first heating device to the thermal energy storage medium by at least partially removing the first portion of the radiant barrier from between the one or more walls defining the first open space and the first heating device.

2. The energy storage system according to claim 1, wherein: The radiation barrier includes multiple sheets of material spaced apart from the one or more walls and spaced apart from each other. 3 . The energy storage system of claim 2 , further comprising a spacing member disposed between at least some of the plurality of sheets of material such that the plurality of sheets of material are spaced apart from each other.

4. The energy storage system according to claim 3, wherein: The spacing member comprises a plurality of individual parts stacked on top of each other. 5 . The energy storage system according to claim 1 , further comprising a heating reservoir configured to contain a fluid, wherein the heating reservoir is disposed in a second open space among the plurality of open spaces.

6. The energy storage system of claim 5, further comprising a second actuator system coupled to a second portion of the radiation barrier, the second portion being disposed between: (i) the one or more walls defining the second open space and (ii) the heating reservoir, and in, The second actuator system is operable to increase radiative heat transfer from the thermal energy storage medium to a fluid contained in the heating reservoir by at least partially removing the second portion of the radiant barrier from between the one or more walls defining the second open space and the heating reservoir.

7. The energy storage system according to any one of claims 1 to 6, wherein: The plurality of open spaces extending within the enclosed interior space include at least two open spaces.

8. The energy storage system according to any one of claims 1 to 7, further comprising at least one additional heating device in addition to the first heating device, wherein each additional heating device is disposed in a corresponding open space among the plurality of open spaces.

9. The energy storage system according to any one of claims 1 to 8, wherein: The horizontal cross section of the thermal energy storage tank has a circular or polygonal outer contour.

10. The energy storage system according to any one of claims 1 to 9, wherein: The thermal energy storage medium includes salt or silicon.

11. The energy storage system according to any one of claims 1 to 10, wherein: The first heating device comprises a resistive heating element.

12. The energy storage system according to any one of claims 1 to 11, wherein: Portions of the radiant barrier not disposed on the one or more walls defining the plurality of open spaces are configured to be stationary relative to the thermal storage tank.

13. The energy storage system according to any one of claims 1 to 12, wherein: The radiation barrier includes at least two sheets of material spaced apart from the one or more walls and spaced apart from each other.

14. A method for storing energy, the method comprising: delivering electrical energy to one or more resistive heating devices, each of the resistive heating devices being disposed in a respective open space of a plurality of open spaces defined by a thermal storage tank located within a vacuum chamber, wherein the thermal storage tank further defines an enclosed interior space containing a thermal storage medium, wherein the plurality of open spaces extend within the enclosed interior space, and wherein a radiation barrier is disposed on an exterior surface of the thermal storage tank; and One or more portions of the radiant barrier are at least partially moved out of the respective open space to increase radiative heat transfer from the one or more resistive heating devices to the thermal energy storage medium.

15. The method according to claim 14, further comprising: After delivering electrical energy to one or more resistive heating devices, the one or more portions of the radiant barrier are moved back into the corresponding open space to reduce radiative heat transfer away from the thermal energy storage medium.

16. The method of claim 14 or 15, further comprising delivering the fluid to a heating reservoir disposed in an additional open space of the plurality of open spaces defined by the thermal energy storage tank.

17. The method according to claim 16, further comprising: Additional portions of the radiant barrier are at least partially moved out of the additional open space to increase radiative heat transfer from the thermal energy storage medium to the fluid.

18. The method according to claim 17, further comprising: After heating the fluid via radiative heat transfer from the thermal energy storage medium, the additional portion of the radiant barrier is moved back into the additional open space to reduce radiative heat transfer away from the thermal energy storage medium.

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