THERMAL ENERGY STORAGE AND POWER SHIFTING SYSTEM

Info

Publication number: 20260266203
Type: Application
Filed: Mar 6, 2026
Publication Date: Sep 10, 2026
Applicant: Holtec International (Camden, NJ)
Inventors: Krishna P. SINGH (Jupiter, FL), Indresh RAMPALL (Cherry Hill, NJ), Edward BELL (Medford, NJ)
Application Number: 19/559,417

Abstract

An electric power generation system having a primary electric power generation system, a bypass branch, and a control subsystem. The primary electric power generation system includes a primary flow loop containing a first working fluid. The primary flow loop includes a primary thermal energy input subsystem which adds thermal energy to the first working fluid flowing therethrough and a primary turbine-generator which generates electricity with thermal energy extracted from the first working fluid. The bypass branch includes an inlet coupled to the primary flow loop downstream of the primary thermal energy input subsystem, an outlet coupled to the primary flow loop downstream of the primary turbine-generator, and a thermal energy storage subsystem which absorbs thermal energy from the first working fluid flowing through the bypass branch for storage. The control subsystem is operably coupled to the bypass branch and can isolate the bypass branch from the primary flow loop.

Description

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of priority to U.S. Provisional Patent No. 63/767,667, filed Mar. 6, 2025, the entirety of which is incorporated by reference.

BACKGROUND OF THE INVENTION

The present invention relates generally to electric power generation systems which generate electricity for sale to the power grid, and more particularly to such a system combined with thermal energy storage and auxiliary power generation capabilities to store thermal energy produced by the power plant during low demand periods of the power grid for generation later when demand and revenue is high.

In power generation markets where electrical demand fluctuates, nuclear or fossil-fueled power plants may operate at economic break-even or negative margins during periods of low demand. This results in inefficient use of the power generation system and the inability to maximize revenue for the power plant. Base load power generation units are particularly affected by this situation as they cannot be quickly ramped up or down in steam production and electric power output for load following operation.

Thus, a need exists for a system that can store the excess energy produced during periods of low electricity demand to be later used to produce additional electricity during periods of high electricity demand.

BRIEF SUMMARY

This disclosure relates to an electrical power generation system that solves the problem above by flowing a portion of the working fluid in a nuclear or fossil-fueled power point through a thermal energy storage subsystem to store thermal energy from the working fluid within a thermal storage medium in the thermal energy storage subsystem for later use.

In one aspect, the invention is a method for operating an electric power generation system operably coupled to an electrical grid with three steps. The first step is a step for heating a first working fluid with a primary thermal energy input subsystem to form a heated first working fluid. The second step is a step for, during a first mode of operation of the electric power generation system, flowing the heated first working fluid through a primary turbine-generator to extract thermal energy from the heated first working fluid to generate electricity for the electrical grid, the primary thermal energy input subsystem and the primary turbine-generator being part of a primary flow loop. The third step is a step for, during a second mode of operation of the electric power generation system, diverting a first portion of the heated first working fluid through a first fluid pathway of a thermal energy storage subsystem via a bypass branch before the primary turbine-generator, a thermal mass composition of the thermal energy storage subsystem absorbing thermal energy from the first portion of the heated first working fluid and storing the absorbed thermal energy.

In a further aspect, the invention is an electric power generation system which includes a primary electric power generation subsystem, a thermal energy storage subsystem containing a thermal mass composition, a bypass branch, and a control subsystem. The primary electric power generation system includes a primary flow loop containing a first working fluid, the primary flow loop comprising a primary thermal energy input subsystem configured to add thermal energy to a first working fluid flowing through the primary loop to form a heated first working fluid and a primary turbine-generator configured to extract thermal energy from the heated first working fluid to generate electricity. The bypass branch includes a bypass branch inlet, a first fluid pathway, and a bypass branch outlet. The bypass branch inlet is fluidly coupled to the primary flow loop to receive a first portion of the heated first working fluid before the primary turbine-generator. The first fluid pathway is part of the thermal energy storage system and is configured to transfer thermal energy from the heated first working fluid flowing through the first fluid pathway to the thermal mass composition for storage. The bypass branch outlet is fluidly coupled to the primary flow loop downstream of the primary turbine-generator. The control subsystem is configured to alternate between fluidly coupling and fluidly isolating the bypass branch to and from the primary flow loop based on an electricity demand of an electrical grid.

In a further aspect, the invention is a method for operating an electrical power generation system with two steps. The first step is a step for heating a first working fluid via a primary thermal energy input subsystem to form a heated first working fluid. The second step is a step for flowing a first portion of the heated first working fluid through a primary flow loop to a primary turbine-generator to extract thermal energy from the first portion of the first working fluid to generate electricity while flowing a second portion of the heated first working fluid through a bypass branch to heat a thermal mass composition in a thermal energy storage vessel.

In a further aspect, the invention is an electric power generation system operably coupled to an electrical grid. The electric power generation system includes a primary flow loop, a bypass branch, an auxiliary flow loop, and a control subsystem. The primary flow loop has a thermal energy input subsystem and a primary turbine-generator. The primary flow loop is configured to flow a first working fluid from the thermal energy input subsystem to the primary turbine-generator to generate electricity. The bypass branch includes a thermal energy storage subsystem. The bypass branch fluidly is also coupled to the primary flow loop downstream of the thermal energy input subsystem. The auxiliary flow includes an auxiliary turbine-generator. The auxiliary flow loop also passes through the thermal energy storage subsystem and is configured to flow a second working fluid to the auxiliary turbine-generator to generate electricity. The control subsystem is coupled to the primary flow loop, the bypass branch, and the auxiliary flow loop, the control subsystem being configured to divert at least a portion of the first working fluid from the primary flow loop to the bypass branch when the electricity generated by the primary turbine-generator is in an excess electricity supply state.

In yet a further aspect, the invention is a method for operating an electric power generation system with two steps. The first step is a step for flowing a first working fluid through a primary flow loop of a primary electric power generation subsystem configured to produce electricity via the first working fluid undergoing a first Rankine cycle in the primary flow loop. The second step is a step for, upon the primary electric power generation subsystem being in an excess electricity supply state, diverting at least a first portion of the first working fluid to a thermal energy storage to heat a thermal mass composition in a thermal energy storage vessel.

Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

All drawings are schematic and not necessarily to scale. Parts given a reference numerical designation in one figure may be considered to be the same parts where they appear in other figures without a numerical designation for brevity unless specifically labeled with a different part number and described herein. Any reference herein to a whole figure number herein which may comprise multiple figures with the same whole number but different alphabetical suffixes shall be construed to be a general reference to all those figures sharing the same whole number, unless otherwise indicated.

The features of the exemplary embodiments of the present invention will be described with reference to the following drawings, where like elements are labeled similarly, and in which:

FIG. 1 is a schematic view of an electric power generation system;

FIG. 2 is a schematic view of a primary power generation system of the electrical power generation system of FIG. 1;

FIG. 3 is a schematic view of an auxiliary power generation subsystem and a bypass branch of the electrical power generation system of FIG. 1; and

FIG. 4 is a graphic representation of the operating stages of the electric power generation system of FIG. 1.

DETAILED DESCRIPTION

The features and benefits of the invention are illustrated and described herein by reference to exemplary (“example”) embodiments. This description of exemplary embodiments is intended to be read in connection with the accompanying drawings, which are to be considered part of the entire written description. Accordingly, the disclosure expressly should not be limited to such exemplary embodiments illustrating some possible non-limiting combination of features that may exist alone or in other combinations of features.

In the description of embodiments disclosed herein, any reference to direction or orientation is merely intended for convenience of description and is not intended in any way to limit the scope of the present invention. Relative terms such as “lower,” “upper,” “horizontal,” “vertical,”, “above,” “below,” “up,” “down,” “top” and “bottom” as well as derivative thereof (e.g., “horizontally,” “downwardly,” “upwardly,” etc.) should be construed to refer to the orientation as then described or as shown in the drawing under discussion. These relative terms are for convenience of description only and do not require that the apparatus be constructed or operated in a particular orientation. Terms such as “attached,” “affixed,” “connected,” “coupled,” “interconnected,” and similar refer to a relationship wherein structures are secured or attached to one another either directly or indirectly through intervening structures, as well as both movable or rigid attachments or relationships, unless expressly described otherwise.

As used throughout, any ranges disclosed herein are used as shorthand for describing each and every value that is within the range. Any value within the range can be selected as the terminus of the range. In addition, all references cited herein to prior patents or patent applications are hereby incorporated by reference in their entireties. In the event of a conflict in a definition in the present disclosure and that of a cited reference, the present disclosure controls.

FIGS. 1-3 illustrate schematic flow diagrams of an electric power generation system 1000. This electric power generation system 1000 is not limited to a specific layout, structure, or dimension, and generically illustrate fluidic connections between individual components and subsystems of the electric power generation system 1000. FIGS. 1-3 illustrate an exemplified embodiment of the electric power generation system 1000, but those skilled in the art will recognize that the systems of methods described herein can be used in other arrangements or configurations as desired.

In the exemplified embodiment of electric power generation system 1000 shown in FIG. 1, the electric power generation system 1000 comprises a primary electric power generation subsystem 100, a bypass branch 200, a thermal energy storage subsystem 300, and an auxiliary electric power subsystem 400. The primary electric power generation subsystem 100 is fluidly coupled to the bypass branch 300 and the thermal energy storage subsystem 200. The auxiliary electric power subsystem 400 is also fluidly coupled with the thermal energy storage subsystem 200. The electric power generation system 1000 further comprises a control subsystem 500. These subsystems will be discussed in further detail in the following paragraphs.

The electric power generation system 1000 is operably coupled to an electric grid 2000. This electrical grid 2000 may take various forms but is generally an interconnected network for electricity distribution. The electrical grid 2000 may an a large network that spans several localities and regions and comprises various substations, diverse types of electrical power generations systems which are connected via electricity transmission lines. Of course, the electrical grid 2000 may also refer to a localized or isolated grid that is not integrated into a larger electrical distribution network. This electrical grid 2000 has a variable electricity demand which may change over time based on time of day, weather conditions, or electrical load requirements.

Referring to FIG. 2 to discuss the exemplified primary electric power generation subsystem 100 in further detail now, the primary electric power generation subsystem 100 comprises a primary flow loop 101 which contains a first working fluid. This first working fluid is a working fluid suitable for driving a power generation cycle such as a Rakine cycle or Brayton cycle. Some examples include air, water, supercritical carbon dioxide, or another such suitable fluid.

The primary flow loop 101 includes various components as well as the fluid conduits that fluidly couple those components with one another. In the exemplified embodiment, the primary flow loop 101 comprises a primary thermal energy input subsystem 110 fluidly coupled to a primary turbine-generator 120. The primary thermal energy input subsystem 110 is a subsystem capable of adding thermal energy to a first working fluid flowing to form a heated first working fluid. In the exemplified embodiment, the primary thermal energy input subsystem 110 comprises a steam generator powered by either nuclear fuel or fuel. A nuclear steam supply system or a fossil fuel powered boiler may be used respectively. An example of the nuclear steam supply system is found in U.S. Pat. No. 9,852,920. The fossil fuel powered boiler may add thermal energy to the working fluid through the combustion of coal, oil, natural gas, or any other suitable fossil fuel.

The primary turbine-generator 120 of the primary flow loop 101 is configured to extract the thermal energy from the heated first working fluid to generate electricity. The primary turbine-generator 120 may comprise a turbine 121 and a generator 122 operably coupled to the turbine 121. In the exemplified embodiment, the primary turbine generator 120 is comprised of both the turbine 121 and the generator 122. The turbine 121 and generator 122 may be separate components that are operably coupled together or they be integrated together into a unitary component. The turbine 121 is a piece of turbomachinery that extracts thermal energy from the heated first working fluid and converts it into rotational mechanical power via turbine blades that are attached to a shaft. This rotational mechanical power rotates a shaft within the generator 122 which converts this rotational mechanical power into electricity for use by the electrical grid 2000. While the primary turbine-generator 120 is exemplified as a single piece of machinery, it is to be understood that in actual embodiments of the invention, multiple turbine generator machinery may be used in combination. Thus, as used herein, the term “primary turbine generator 120” covers both singular machines and multiple machines working in combination. This logic applies to all machines and terminology used herein when applicable.

The primary flow loop 101 may further comprise a primary condenser 130 downstream of the primary turbine-generator 120. The primary condenser 130 is configured to form a condensed first working fluid from the first working fluid after the first working fluid exits the primary turbine-generator 120. The primary condenser 130 in the exemplified embodiment is a heat-exchanger that coverts the first working back into condensate so that it can be flowed back into the primary thermal energy input subsystem 110. The primary condenser 130 may be a water-cooled condenser or air-cooled condenser depending on the electrical power generation system 1000's requirements.

The primary flow loop 101 may further comprise a primary flow loop pump 102 and a primary preheater 140 downstream of the primary condenser 130. The primary flow loop pump 102 pumps the condensed first working fluid from the primary condenser 130 so that it can flow into the primary thermal energy input 110 again. In embodiments that comprise the primary preheater 140, the primary preheater 140 is downstream of the primary flow loop pump 102 and is further fluidly coupled to the primary turbine-generator 120 by fluid pathway 105. Fluid pathway 105 is fluidly coupled to the turbine 121 of the primary-turbine generator 120. The fluid pathway 105 may be fluidly coupled to various extraction points along the turbine 121 such as after a high-pressure portion of the turbine 121, an intermediate pressure portion of the turbine 121, a low-pressure portion of the turbine 121, or a combination thereof. The primary preheater 140 is configured to use a portion of the first working fluid flowing through the primary turbine-generator 120 to add thermal energy to the condensed first working fluid to increase the thermal efficiency of the primary electric power generation subsystem 100. Although not specifically shown, the working fluid extracted from the turbine 121 and used by the primary preheater 140 to preheat the condensed first working fluid may itself be flowed through the condenser to join the condensed first working fluid before it enters the primary flow loop pump 102.

The bypass branch 200 with now be described. As shown in FIG. 1, the bypass branch 200 is fluidly coupled with the primary flow loop 101 and may utilize the same type of fluid conduits as the primary flow loop 101. The bypass branch 200 is configured to extract a first portion of the heated first working fluid before the primary turbine-generator 120.

In the exemplified embodiment, a bypass inlet 201 of the bypass branch 200 is coupled to the primary flow loop 101 at a first position and a bypass outlet 202 of the bypass branch 200 is coupled to primary flow loop 101 at a second position. The first position is downstream of the primary flow loop 101 so that bypass branch inlet 201 is fluidly coupled to the primary flow loop 101 to receive a first portion of the heated first working fluid before the primary turbine-generator 120. In the exemplified embodiment, the first position is between the primary thermal energy input subsystem 110 and the primary turbine-generator 120 and the bypass branch inlet 201 has a first connection branch 203. In alternative embodiments, the first position may be directly downstream of the primary thermal energy input subsystem 110 and the bypass branch inlet has a second connection branch 204. In further alterative embodiments, the first position is within the turbine 121 of the turbine-generator 120. In the exemplified embodiment, the bypass branch outlet 202 is fluidly coupled to the primary condenser 130 at the second position. In all the embodiments, the first and second positions are chosen so that the first working fluid undergoes expansion in the turbine 121 of the primary turbine-generator 120 so that the first portion of the heated working fluid from the primary thermal energy input subsystem 110 does not undergo expansion that drives the primary turbine-generator. This ensures that extract portion of the heated first working fluid retains all the thermal energy added from the primary thermal energy input subsystem 110 when it enters the bypass branch 200.

Now referring to FIG. 3, the bypass branch 200 in the exemplified embodiment further comprises a first fluid pathway 301 that runs through the thermal energy storage subsystem 300. This first fluid pathway 301 may also formed as part of the thermal energy storage subsystem 300 and be fluidly coupled to the bypass inlet 201 and the bypass outlet 202 of the bypass branch at either end. The first fluid pathway 301 is shown as a comprises a first set of heat exchange tubes which transfer thermal energy from the first portion of the heated first working fluid flowing through the first fluid pathway 301 to the thermal energy storage subsystem 300. The individual tubes of this first set of heat exchange tubes are spaced apart from one another to ensure that transfer of thermal energy from the first portion of the heated first working fluid to the thermal energy storage is evenly distributed. Of course, in other embodiments, the first fluid pathway may be a single tube running through the thermal energy storage subsystem 300. Further details of the first fluid pathway's 301 function will be discussed below with reference to the thermal energy storage subsystem 300.

With continued reference to FIG. 3, the thermal energy storage subsystem 300 will now be discussed in further detail. The thermal energy storage subsystem 300 is fluidly coupled to the bypass branch 200 and auxiliary electric power generation subsystem 400 and contains a thermal mass composition M within an internal cavity 310. Thermal energy storage subsystem 300 comprises an insulated body that defines the internal cavity 310. The thermal energy storage subsystem 300 may have an overall cylindrical shape. Alternatively, the thermal energy storage subsystem 300 may be a rectangular cuboid configuration. In the exemplified embodiment shown in the FIGS. 1 and 3, the thermal energy storage subsystem 300 is shown as a single unit. However, in alternate embodiments, the thermal energy storage subsystem 300 may be comprised of several separate modules that can either be fluidly isolated or fluidly coupled together.

The thermal mass composition M contained within the internal cavity 310 of the thermal energy storage subsystem 300 is operable to store thermal energy and is a high heat retention capacity granular particulate mass forming a continuum of particles which fills the internal cavity 310 of the thermal energy storage subsystem 300.

Thermal mass composition M will now be further described.

Any suitable thermal mass composition M may be used which can be customized and selected for the required thermal duty and operating parameters of the electric power generation system 10000. In the exemplified embodiment, thermal mass composition M comprises a mixture that includes a phase change material (“PCM”) in combination with one or more metallic materials. Both the PCM and metallic materials of the mixture may be in the form of solid granular particles at ambient temperatures when not heated by the thermal mass composition M. The PCM material may have a lower melting temperature than the metallic materials in one embodiment such that PCM material melts when initially heated by the first working fluid while the metallic materials remain in a solid particle state. Both the base metallic material(s) and PCM are materials having properties configured to produce a thermal mass operable to absorb and store heat, and release that heat on demand when required to heat the second heat transfer fluid and the working fluid flowing through the thermal energy storage subsystem 300.

The at least one base metallic material may constitute a majority of the mixture or composition and has a higher melting point or temperature Tbm than the melting point or temperature Tpcm of the PCM. Temperature Tpcm may be lower than the normal operating temperature Tnm of the thermal mass composition M to which the mass will be heated for normal operation such that the PCM melts and changes to a liquid or molten state when the thermal mass is heated. At ambient temperatures, the PCM is in a solid particle state.

By contrast, the at least one base metallic material may have a melting temperature Tbm greater than the normal operating temperature Tmm, and preferably greater than the maximum temperature Tmax of the thermal mass composition M such that the base metallic material always remains in a solid particle state when thermal energy is added to the thermal mass composition. In some representative but non-limiting examples, the base metallic material may have a melting temperature Tbm greater than 1,000 degrees C. (Celsius), or greater than 2,000 degrees C. in some embodiment, whereas the PCM may have a melting temperature Tpcm less than 1,000 degrees C. The metallic material may comprise a single one or a combination of ferrous and/or non-ferrous metal particles selected to optimize heat retention capabilities and meeting the foregoing melting temperature criteria.

In preferred but non-limiting embodiments, the PCM used may be a salt which may be converted from a granular solid particle state at ambient temperatures to a liquid/molten state when heated. Any suitable salt may be used which is selected for the required thermal duty.

Some examples of salts which may be used to form the PCM in each thermal energy storage vessel 300 are shown in the following table:

T_melt Latent (° C.) Material Heat (kJ/kg) 94 60 wt % AlCl₃+ 14% KCl + 26% NaCl 213 150 66 wt % AlCl₃+ 34% NaCl 201 202 7.5 wt % NaCl + 23.9% KCl + 68.6% ZnCl₂ 200 258 59 wt % NaOH + 41% NaNO₃ 292 307 NaNO₃ 177 318 77.2 mol % NaOH − 16.2% NaCl − 6.6% Na₂CO₃ 290 320 54.2 mol % LiCl − 6.4% BaCl₂− 39.4% KCl 170 335 KNO₃ 88 340 52 wt % Zn − 48% Mg 180 348 58 mol % LiCl − 42% KCl 170 370 26.8% NaCl − 73.2% NaOH 320 380 KOH 149.7 380 45.4 mol % MgCl₂− 21.6% KCl − 33% NaCl 284 381 96 wt % Zn − 4% Al 138 397 37 wt % Na₂CO₃− 35% K₂CO₃− 31% Li₂CO₃ 275 430 56 wt % NaCl − 44% MgCl₂ 168 443 59 wt % Al − 35% Mg − 6% Zn 310 450 48 wt % NaCl − 52% MgCl₂ 430 470 36 wt % KCl − 64% MgCl₂ 388 487 56 wt % Na₂CO₃− 44% Li₂CO₃ 368 500 33 wt % NaCl − 67% CaCl₂ 281 550 LiBr 203 632 46 wt % LiF − 44% NaF₂− 10% MgF₂ 858 658 44.5 wt % NaCl − 55.5% KCl 388 714 MgCl₂ 452 801 NaCl 510

The melt temperatures and latent heat properties of the salt are properties and factors which direct the selection of the type salt for the required thermal duty and temperature increase of the heat transfer fluid. It bears noting that the type of salt used in each thermal energy storage subsystem 300 may therefore be customized and different. Regardless of the application including simply heating water for district heating or other applications, it is apparent to those skilled in the art that thermal duty and performance of the thermal energy storage subsystem 300 is highly customizable to meet the required temperature increase objectives of the thermal energy system.

It bears noting that any suitable PCM may be used other than the salts such as those listed above may be used so long as the melting temperature Tpcm of the PCM is less than the normal operating temperature Tnm of the thermal mass composition M during operation of the thermal energy storage subsystem 300.

The first fluid pathway 301 of the thermal energy storage subsystem 300 and the bypass branch 200 is at least partially embedded in the thermal mass composition M. The thermal energy storage subsystem may further comprise a second fluid pathway 302 which may also form part of the auxiliary electric power generation system 400. As will the first fluid pathway 301, the second fluid pathway 302 may comprise a second set of heat exchange tubes which are configured to absorb thermal energy from the thermal mass composition M and transfer it to a second working fluid flowing therethrough. The individual tubes of second of heat exchange tubes are spaced apart from one another to ensure that transfer of thermal energy from the thermal mass composition M to the second working fluid is evenly distributed. Of course, in other embodiments, the first fluid pathway may be a single tube running through the thermal energy storage subsystem 300. As shown in the exemplified embodiment, both the first fluid pathway 301 and the second fluid pathway are at least partially embedded in the thermal mass composition M.

Referring more specifically to both the first fluid pathway 301 and the second fluid pathway 302, the second set of heat exchange tubes of each of the first fluid path 301 and the second fluid pathway 302 may be formed by a plurality of metallic heat exchange tubes. In the exemplified embodiment, these tubes are vertically oriented. However, in other embodiments, the metallic heat exchange tubes may be horizontally oriented or oriented off a horizontal or vertical axis. Each set of heat exchange tubes of the first fluid pathway 301 and the second fluid pathway 302 may comprise straight tubes which are fluidly coupled at their ends to inlet and outlet headers located at the top and bottom of the thermal energy storage subsystem 300. In other embodiments, the sets heat exchange tubes of the first fluid pathway 301 and the second fluid pathway 302 may comprise U-shaped tubes fluidly coupled to an inlet and outlet header or flow plenum.

The auxiliary electric power generation subsystem 400 will now be described in further detail. The auxiliary electric power generation subsystem 400 in the exemplified embodiment comprises an auxiliary flow loop 401 which contains a second working fluid. The auxiliary flow loop 401 includes various components as well as the fluid conduits that fluidly couple those components with one another. The second working fluid is a working fluid suitable for driving a power generation cycle such as a Rakine cycle or Brayton cycle. Some examples include air, water, supercritical carbon dioxide, or another such suitable fluid. In the exemplified embodiment, the second working fluid may be the same fluid as the first working fluid. However, the second working fluid may also be a different working fluid for the first working fluid if the primary power generation subsystem 100 is driving a different power generation cycle from the auxiliary power generation subsystem 400. For instance, if the primary power generation subsystem 100 drives a Rankine cycle and the auxiliary power generation subsystem 400 drives a Brayton cycle, the first working fluid may be water and the second working fluid may be air.

Similar to the primary power generation subsystem 100, the auxiliary power subsystem comprises an auxiliary turbine-generator 420. The auxiliary turbine-generator 420 is part of the auxiliary flow loop 401 downstream of the thermal energy storage subsystem 300. As with the primary turbine-generator 120, the auxiliary turbine-generator 420 may comprise an auxiliary turbine 421 and an auxiliary generator 422 operably coupled to the auxiliary turbine 421. In the exemplified embodiment, the auxiliary turbine-generator 420 is comprised of both the auxiliary turbine 421 and the auxiliary generator 422. The auxiliary turbine 421 and auxiliary generator 422 may be separate components that are operably coupled together or they be integrated together into a unitary component. The auxiliary turbine 421 is a piece of turbomachinery that extracts thermal energy from the heated first working fluid and converts it into rotational mechanical power via turbine blades that are attached to a shaft. This rotational mechanical power rotates a shaft within the auxiliary generator 422 which converts this rotational mechanical power into electricity for use by the electrical grid 2000. While the auxiliary turbine-generator 420 is exemplified as a single piece of machinery, it is to be understood that in actual embodiments of the invention, multiple turbine generator machinery may be used in combination. Thus, as used herein, the term “primary turbine generator 420” covers both singular machines and multiple machines working in combination. This logic applies to all machines and terminology used herein when applicable.

It bears noting that in some embodiments the auxiliary turbine-generator 420 may have a smaller electricity generation capacity than the primary turbine-generator 120. For instance, if the auxiliary flow loop 401 drives a Rankine cycle, the steam output from the thermal energy storage subsystem 300 may be less than the primary thermal energy input subsystem 110. The combined electricity generation capacity of both the primary turbine-generator 120 and the auxiliary turbine-generator 420 is greater than the electricity generation capacity of the primary turbine-generator 120 alone.

The auxiliary flow loop 401 may also comprise the second fluid pathway 302 of the thermal energy storage subsystem 300. The auxiliary flow loop 401 is configured to flow a second working fluid through the second fluid pathway 302 of the thermal energy storage subsystem 300 to absorb thermal energy from the thermal mass composition M to form a heated second working fluid and then flow the heated second working fluid to the auxiliary turbine-generator 420 to extract thermal energy from the heated second working fluid to generate electricity. As shown in FIG. 3, first fluid pathway 301, which may be formed as part of the bypass branch 200, and the second fluid pathway 302 loop are fluidly isolated from one another.

The auxiliary flow loop 401 of the auxiliary power generation subsystem 400 may further comprise an auxiliary condenser 430 downstream of the auxiliary turbine-generator 420. The auxiliary condenser 430 being configured to form a condensed second working fluid from the second working fluid after the second working fluid exits the auxiliary turbine-generator 420. The auxiliary condenser 430 in the exemplified embodiment is a heat-exchanger that converts the second working into condensate so that it can be flowed back into the thermal energy storage subsystem 300. The auxiliary condenser 430 may be a water-cooled condenser or air-cooled condenser depending on the electrical power generation system 1000's requirements.

The auxiliary flow loop 401 may further comprise an auxiliary flow loop pump 402 and an auxiliary preheater 440 downstream of the auxiliary condenser 430. The auxiliary flow loop pump 302 pumps the condensed second working fluid from the auxiliary condenser 430 so that it can flow into the thermal energy storage subsystem 300 again. In the exemplified embodiment, the auxiliary preheater 440 is fluidly coupled to the auxiliary turbine-generator 420 via a fluid pathway 405. The auxiliary preheater 440 is configured to use a portion of the second working fluid flowing through the auxiliary turbine-generator 420 to add thermal energy to the condensed second working fluid. The auxiliary preheater 440 is configured to use a portion of the heated second working fluid flowing through the auxiliary turbine-generator 420 to add thermal energy to the condensed first working fluid to increase the thermal efficiency of the auxiliary electric power generation subsystem 400. Although not specifically shown, the second working fluid extracted from the turbine 421 and used by the primary preheater 440 to preheat the condensed second working fluid may itself be flowed through the auxiliary condenser 430 to join the condensed second working fluid before it enters the auxiliary flow loop pump 402.

Referring back to FIG. 1, the control subsystem will now be described in greater detail.

The control subsystem 500 which serves to switch the electric power generation system 1000 between different modes of operation. In the exemplified embodiment, the control subsystem 500 is an automated system that comprises the requite computational hardware for automatically controlling the electric power generation system 1000. Such computation hardware may include a programmable processor-based control which is configured, via program instructions or control logic, to synchronize, sequence, and control the operation of the primary electric power generation subsystem 100, the bypass branch 200, and the auxiliary electric power generation subsystem 400. The control subsystem 500 may further comprise a computer memory medium which can be a hard drive that comprises sufficient memory to store all of the necessary computer code, algorithms, and data necessary for the operation and functioning of electric power generation system 1000. Of course, in other embodiments, the control subsystem 500 may be a partially or manually operated subsystem that relies on the operators of the electric power generation system 1000 to perform the some or all of the functions of the control subsystem 500 described herein.

The primary function of the control subsystem 500 is to switch the electric power generation system 1000 between first, second, and third modes of operation based on an electricity demand of the electrical grid 2000. In the exemplified embodiment. The control subsystem 500 is configured to activate the auxiliary electric power generation subsystem when the primary electric power generation subsystem is in a deficient electricity supply state. To accomplish this, the control subsystem 500 is configured to alternate between fluidly coupling and fluidly isolating the bypass branch 200 to and from the primary flow loop 101 based on an electricity demand of an electrical grid. In the exemplified embodiment, this is accomplished by opening and closing bypass branch valves 501 which are operably coupled to the bypass branch 200. Further details on the method of operating the electric power generation system 1000 with the control subsystem 500 are discussed in the following paragraphs.

Methods of operating the electric power generation system 1000 will not be described in further detail. The methods will be described in relation to the exemplified power generation system 1000 of FIGS. 1-3 for ease of description and understanding. However, these methods are not limited to any specific structure or system and can be carried out by other systems and/or apparatus. Of course, those skilled in the art will recognize that operations and steps discussed below may be performed in alterative orders or in alterative sequences those described as needed or desired.

A general method of operating the electric power generation system 1000 comprises first heating the first working fluid with the primary thermal energy input subsystem 110 to form the heated first working fluid. If steam is used as the first working fluid, the steam is heated by the primary thermal energy input subsystem 110 to form superheated steam. The first working fluid then flows through the primary flow loop 101 from the primary thermal energy input system 110 to the primary turbine-generator 120 where the heated first working fluid is used by the turbine 121 and the generator 122 to generate electricity.

When all of the heated first working fluid is flowing through the primary turbine-generator 120, the primary turbine-generator 120 is producing electricity at its maximum capacity. If electricity demand from the electrical grid 2000 level with the capacity of the primary turbine-generator 120, then the primary turbine-generator 120 is in a level electricity supply state” and control subsystem 500 operates the electric power generation system 1000 in a first mode of operation. However, if the electricity demand from the electrical grid is less than the capacity of the primary turbine-generator 120, then the primary turbine-generator 120 is in an excess electricity supply state and the control subsystem 500 opens the bypass branch valves 501 to operate the electric power generation system 1000 in a second operation mode. In the second operation mode, a first portion of the heated first working fluid flows through the bypass branch 200 to deliver thermal energy to the thermal energy storage subsystem 300 for later use. A second portion of the heated working fluid continues to flow through the primary turbine-generator.

Finally, if the electricity demand from the electricity grid 2000 exceeds the capacity of the primary turbine-generator 120, the primary turbine-generator 120 is in a deficient electricity supply state. When the primary turbine-generator 120 is in a deficient electricity supply state, the control subsystem 500 operates the electric power generator 1000 in a third mode of operation by closing the bypass branch valves 501 and flowing the second working fluid through the thermal energy storage subsystem to absorb thermal energy and then deliver it to the auxiliary turbine-generator 420 to generate additional electricity. In this manner, the electric power generation system 1000 is capable of meeting additional electricity demand from the electrical grid 2000.

In first, second, and third operation modes, the portion of the working fluid that flows through the primary turbine-generator 120 then flows through the primary condenser 130 where it is converted into a condensed first working fluid. In the second mode of operation, the first portion of the first working fluid flows through the bypass outlet 202 to join the rest of the first working fluid in the primary condenser 130 and form the condensed first working fluid. The condensed first working fluid may then flow through the primary preheater 140 where another portion of the heated first working fluid from the primary turbine-generator 120 flows to the primary preheater 140 via the fluid pathway 105 and preheats the condensed first working fluid before it reenters the primary thermal energy input subsystem 110.

In the third operation mode, after the second working fluid exits the auxiliary turbine-generator 420 the second working fluid then flows through the auxiliary condenser 430 where it is converted into a second working fluid condenser. As with the first working fluid in the primary flow loop 101, the condensed second working fluid may then flow through the auxiliary preheater 440 where another portion of the heated second working fluid from the auxiliary turbine-generator 420 flows to the auxiliary preheater 420 via a fluid pathway 405 and preheats the condensed first working fluid before it reenters the thermal energy storage subsystem 300.

A more specific method of operating the electric power generation system 1000 will not be described. This method comprises three steps: step a), step b), and step c). Step a) comprises heating the first working fluid with the primary thermal energy input subsystem 110 to form a heated first working fluid. In embodiments where the primary thermal energy input 110 is a nuclear steam supply system, the first working fluid flows, via the primary flow loop 101, through the steam generator on the nuclear steam suppler to absorb thermal energy from a heat transfer fluid that had received energy from the a nuclear reactor. Alternatively, in embodiments where the primary thermal energy input 110 is not a nuclear steam supply system, the first working fluid flows through a boiler which is part of the primary thermal energy input subsystem 110 to become the heated first working fluid.

After step a) is performed, the electric power generation system 1000 performs step b). Step b) comprises operating the electric power generation system 1000 in a first mode of operation. In this first mode of operation, the primary flow loop 101 flows the heated first working fluid through the primary turbine-generator 120 to extract thermal energy from the heated first working fluid to generate electricity for the electrical grid 2000. This is done by forcing the heated, high pressure, first working fluid through stationary nozzles or stator blades and onto rotor blades which generates rotational energy that the generator 122 then converts into electricity. This step may further comprise isolating the bypass branch 200 from the primary flow loop 101 to prevent flow of the heated first working fluid through the bypass branch 200.

After step b) is performed, the electric power generation system 1000 may perform step c). Step c) comprises operating the electric power generation system 1000 in a second mode of operation. During the second mode of operation, the bypass branch 200 is no longer isolated from the primary flow loop 101, and a first portion of the heated first working fluid is diverted through a first fluid pathway 301 of a thermal energy storage subsystem 300 via a bypass branch 200 before it can enter the primary turbine-generator 120. Diverting this first portion of the heated working fluid through the first fluid pathway 301 allows the thermal mass composition M of the thermal energy storage subsystem 300 to absorb thermal energy from the first portion of the heated first working fluid for storage.

The method for operating the electric power generation system 1000 may further comprise a step d) which is performed after step c). Step d) comprises operating the electric power generation system 1000 in a third operation mode. During the third mode of operation, the electric power generation system 1000 performs three sub-steps. In the first sub-step d-1), a substantial entirety of the heated first working fluid flows through the primary turbine-generator 120 to extract thermal energy from the heated first working fluid to generate a first amount of electricity for the electrical grid 2000. In the second sub-step d-2), the second working fluid flows through the second fluid 302 pathway of the thermal energy storage subsystem 300 so that the second working fluid absorbs the stored thermal energy from the thermal mass composition M to form the heated second working fluid. In the third sub-step d-3), the heated second working fluid flows through the auxiliary turbine-generator 420 to extract thermal energy from the heated second working fluid to generate a second amount of electricity for the electrical grid 2000. Each of these sub-steps may be performed simultaneously or sequentially depending on the operating requirements of the electric power generation system 1000.

While this method is being performed by the electric power generation system 1000, the control subsystem 500 selects between the first, second, and third modes of operation based on electricity demand of the electrical grid 2000 relative to a maximum amount of electricity output that can be generated by the primary turbine-generator 120 when the substantial entirety of the heated first working fluid flows through the primary flow loop. The maximum about of electricity output that the primary turbine-generator 120 will be referred to as the primary turbine-generator's 120 capacity. In the electrical grid 2000 is a widespread or regional electric grid, the control subsystem 500 may switch between the first, second, and third modes of operation based on the time of day, stored history of electricity demand, or by manual decision of an operator of the electric power generation system 1000.

FIG. 4 provides an illustration of what mode of operation the electric power generation system 1000 is operating in based on the electricity demand relative to the capacity of the primary turbine-generator 120. Moving from left to right, when the electricity demand is less than 85% of the capacity of the primary turbine generator 120, the primary turbine-generator 120 is in an excess electricity supply state and the control subsystem 500 operates the electric power generation system 1000 in the second mode. In one embodiment, the excess electricity supply state may be a state in which the output capacity (i.e. the maximum electricity generation of) the primary turbine-generator 120 is greater than the electricity being demanded from the electrical grid 2000. Thought of another way, and in another embodiment, the excess electricity supply state may be a state in which the amount of electricity that can be outputted by the primary turbine-generator 120 when the entire volume of the heated first working fluid exiting the primary thermal energy input subsystem 110 exceeds the electricity being demanded by the electrical grid 2000. In still another embodiment, the excess electricity supply state may be a state in which the amount of electricity that is generated by the primary turbine-generator 120 exceeds the electricity being demanded by the electrical grid 2000. Furthermore, while a threshold of less than 85% electricity demand to electricity output capacity of the primary turbine generator 120 is exemplified, it is to be understood that the invention is not limited to any specific threshold or range and the parameters for switching between the first, second, and third modes may be set by the plant operations engineers or other qualified persons.

Still referring to the example of FIG. 4, when the electricity demand is between 85% and 90% of the capacity of the primary turbine-generator 120, the primary turbine generator is in a level electricity supply state and the control subsystem 500 operates the electric power generation system 1000 in the first mode. In other embodiments, the “level electricity supply state” may correspond to other ranges and/or singular thresholds as established by the plant operations engineers or other qualified persons. As such, the invention is not limited to any specific range or threshold for the term “level electricity supply state” in certain embodiments. As used herein, the “level electricity supply state” may be a state in which the primary turbine-generator 120 is meeting (i.e., not falling short of satisfying) the demand from the electrical grid 2000 but does not have the capacity to generate an overly large amount of excess electricity despite receiving full flow of the heated first working fluid from the primary thermal energy input subsystem 110.

Finally, and still referring to the example of FIG. 4, when the electricity demand is greater than 90% of the capacity of the primary turbine-generator 120, the primary turbine-generator 120 is in a deficient electricity supply state and the control subsystem 500 operates the electric power generation system in the third mode. In the deficient electricity supply state, the primary turbine-generator 120 is not meeting (or is close to not being able to safely meet) the demand from the electrical grid 2000 and the auxiliary power generation subsystem 400 will be used to meet the demand. While a threshold of greater than 90% electricity demand to electricity output capacity of the primary turbine generator 120 is exemplified as being the threshold for the “deficient electricity supply state,” it is to be understood that the invention is not limited to any specific threshold or range in this regard. For example, in another embodiment, the threshold may be when the demand is greater than 100% of the capacity. In fact, the invention is not limited to any specific range or threshold for the term “deficient electricity supply state” in certain embodiments. As used herein, the “deficient electricity supply state” may be a state in which the primary turbine-generator 120 is unable to safely and/or reliably meet the electricity demand from the electrical grid 2000 despite receiving full flow of the heated first working fluid from the primary thermal energy input subsystem 110.

The control subsystem 500 may transition the electric power generation system 1000 between the second mode, first mode, and third mode upon detecting that the electricity demand has crossed over one of the capacity thresholds discussed above by a certain amount for a certain amount of time. For example, the control subsystem may transition the electric power generation system 1000 from one mode to another when the electricity demand from the electrical grid 2000 is between +/−10%, 5%, or 1% of a given threshold for 1 hour, 30 minutes, 10 minutes, 5 minutes, 1 minute, or even 30 seconds or less. This ensures some amount of delay between the transition of one mode to the other to prevent overly frequent and inefficient switching.

When the control subsystem 500 transitions the electric power generation system 1000 between the second mode to the first mode, the control subsystem 500 may send a first signal to close the plurality of bypass valves 501 and when control subsystem transitions the electric power generation system 1000 from the second mode to the first mode, the control subsystem may send a second signal to open the plurality of bypass valves 501. Upon transitions into the third mode, the control subsystem 500 may send a third signal to the auxiliary power generation subsystem 400 to begin flowing the second working fluid through the auxiliary flow loop 401. The first, second, and third signals may be entirely electrical signals sent through wired or digital connections. In other embodiments, the first, second, and third signals may be sent through mechanical subsystems such as pneumatically actuated pipes.

Exemplary Claim Set

The following is a non-limiting list of example claims to several embodiments of the present invention.

Exemplary claim 1: A method for operating an electric power generation system operably coupled to an electrical grid, the method comprising: a) heating a first working fluid with a primary thermal energy input subsystem to form a heated first working fluid; b) during a first mode of operation of the electric power generation system, flowing the heated first working fluid through a primary turbine-generator to extract thermal energy from the heated first working fluid to generate electricity for the electrical grid, the primary thermal energy input subsystem and the primary turbine-generator being part of a primary flow loop; and c) during a second mode of operation of the electric power generation system, diverting a first portion of the heated first working fluid through a first fluid pathway of a thermal energy storage subsystem via a bypass branch before the primary turbine-generator, a thermal mass composition of the thermal energy storage subsystem absorbing thermal energy from the first portion of the heated first working fluid and storing the absorbed thermal energy.

Exemplary claim 2: The method according to exemplary claim 1 further comprising: during a third mode of operation of the electric power generation system: d-1) flowing a substantial entirety of the heated first working fluid through the primary turbine-generator to extract thermal energy from the heated first working fluid to generate a first amount of electricity for the electrical grid; and d-2) flowing a second working fluid through a second fluid pathway of the thermal energy storage subsystem so that the second working fluid absorbs the stored thermal energy from the thermal mass composition to form a heated second working fluid; d-3) flowing the heated second working fluid through an auxiliary turbine-generator to extract thermal energy from the heated second working fluid to generate a second amount of electricity for the electrical grid, the second fluid pathway of the thermal energy storage subsystem and the auxiliary turbine-generator being part of an auxiliary flow loop.

Exemplary claim 3: The method according to claim 2 wherein the electric power generation system comprises a control subsystem, the control subsystem configured to select between the first, second, and third modes of operation based on an electricity demand of the electrical grid.

Exemplary claim 4: The method according to exemplary claim 3 wherein the control subsystem is configured to select between the first, second, and third modes of operation based on the electricity demand of the electrical grid relative to a maximum amount of electricity output that can be generated by the primary turbine-generator when the substantial entirety of the heated first working fluid flows through the primary flow loop.

Exemplary claim 5: The method according to exemplary claim 3 wherein the control subsystem is configured to: operate the electric power generation system in the second mode when the primary turbine-generator is in an excess electricity supply state; operate the electric power generation system in the third mode when the primary turbine-generator is in a deficient electricity supply state; and operate the electric power generation system in the first mode when the primary turbine-generator is in a level electricity supply state.

Exemplary claim 6: The method according to any one of exemplary claims 1 to 5, wherein step c) further comprises, during the second mode of operation of the electrical power generation system, flowing a remaining portion of the heated first working fluid through the primary turbine-generator to extract thermal energy from the second portion of the heated first working fluid to generate electricity.

Exemplary claim 7: The method according to any one of exemplary claim 2, wherein the electric power generation system comprises a control subsystem, the control subsystem configured to select between the first and second modes of operation based on an electricity demand of the electrical grid relative to a maximum amount of electricity output that can be generated by the primary turbine-generator when the substantial entirety of the heated first working fluid flows through the primary flow loop; and wherein the control subsystem is configured to: (i) operate the electric power generation system in the first mode of operation when the primary turbine-generator is in a level electricity supply state; and (ii) operate the electric power generation system in the second mode of operation when the primary turbine-generator is in an excess electricity supply state.

Exemplary claim 8: The method according to any one of exemplary claims 1 to 7, wherein step b) further comprises isolating the bypass branch from the primary flow loop to prevent flow of the heated first working fluid through the bypass branch.

Exemplary claim 9: The method according to any one of claims 1 to 8, wherein the bypass branch comprises a bypass branch inlet fluidly coupled to the primary flow loop at a first position and a bypass branch outlet fluidly coupled to the primary flow loop at a second position, the first and second positions selected so that the first portion of the heated working fluid from the primary thermal energy input subsystem does not undergo expansion that drives the primary turbine-generator.

Exemplary claim 10: The method according to any one of exemplary claims 1 to 9 wherein the first fluid pathway of the thermal energy storage subsystem comprises a first set of heat exchange tubes at least partially embedded in the thermal mass composition.

Exemplary claim 11: The method according to exemplary claim 2 wherein the first fluid pathway of the thermal energy storage subsystem comprises a first set of heat exchange tubes at least partially embedded in the thermal mass composition; wherein the second fluid pathway of the thermal energy storage subsystem comprises a second set of heat exchange tubes at least partially embedded in the thermal mass composition, the first and second sets of heat exchange tubes being fluidly isolated from one another; and wherein the thermal energy storage subsystem comprises an insulated vessel having an internal cavity containing the thermal mass composition.

Exemplary claim 12: The method according to exemplary claim 2 wherein the bypass branch and the auxiliary flow loop are fluidly isolated from one another.

Exemplary claim 13: An electric power generation system comprising: a primary electric power generation subsystem comprising a primary flow loop containing a first working fluid, the primary flow loop comprising a primary thermal energy input subsystem configured to add thermal energy to a first working fluid flowing through the primary loop to form a heated first working fluid and a primary turbine-generator configured to extract thermal energy from the heated first working fluid to generate electricity: a thermal energy storage subsystem containing a thermal mass composition; a bypass branch comprising, in fluid coupling; a bypass branch inlet fluidly coupled to the primary flow loop to receive a first portion of the heated first working fluid before the primary turbine-generator; a first fluid pathway of the thermal energy storage subsystem configured to transfer thermal energy from the heated first working fluid flowing through the first fluid pathway to the thermal mass composition for storage; and a bypass branch outlet fluidly coupled to the primary flow loop downstream of the primary turbine-generator; and a control subsystem configured to alternate between fluidly coupling and fluidly isolating the bypass branch to and from the primary flow loop based on an electricity demand of an electrical grid.

Exemplary claim 14: The electrical power generation system according to exemplary claim 13 further comprising an auxiliary electric power generation subsystem comprising an auxiliary turbine-generator, the auxiliary turbine-generator being part of an auxiliary flow loop which comprises a second fluid pathway of the thermal energy storage subsystem, the auxiliary flow loop configured to flow a second working fluid through the second fluid pathway of the thermal energy storage subsystem to absorb thermal energy from the thermal mass composition to form a heated second working fluid and then flow the heated second working fluid to the auxiliary turbine-generator to extract thermal energy from the heated second working fluid to generate electricity.

Exemplary claim 15: The electrical power generation system according to exemplary claim 14 wherein the bypass branch and the auxiliary flow loop are fluidly isolated from one another.

Exemplary claim 16: The electrical power generation system according to any one of exemplary claims 14 to 15 wherein the first fluid pathway of the thermal energy storage subsystem is formed by a first set of heat exchange tubes at least partially embedded in the thermal mass composition; wherein the second fluid pathway of the thermal energy storage subsystem is formed by a second set of heat exchange tubes at least partially embedded in the thermal mass composition; and wherein the thermal energy storage subsystem comprises an insulated vessel having an internal cavity containing the thermal mass composition.

Exemplary claim 17: The electrical power generation system according to any one of exemplary claims 14 to 16 wherein the thermal mass composition comprises a mixture of phase change material and a metallic powder.

Exemplary claim 18: The electric power generation system according to any one of exemplary claims 14 to 17 wherein the control subsystem is configured to activate the auxiliary electric power generation subsystem when the primary electric power generation subsystem is in a deficient electricity supply state.

Exemplary claim 19: The electric power generation system according to any one of exemplary claims 13 to 18 wherein the control subsystem is configured to fluidly couple the bypass branch to the primary flow loop to allow the first portion of the heated first working fluid to flow through the bypass branch and heat the thermal mass composition when the primary electric power generation subsystem is in an excess electricity supply state.

Exemplary claim 20: The electric power generation system according to any one of exemplary claims 13 to 19 wherein the control subsystem is configured to fluidly isolate the bypass branch from the primary flow loop to prevent the heated first working fluid from flowing through the bypass branch when the primary electric power generation subsystem is in a deficient electricity supply state or in a level electricity supply state.

Exemplary claim 21: The electric power generation system according to any one of exemplary claims 14 to 20 wherein the control subsystem is configured to deactivate the auxiliary electric power generation subsystem when the primary electric power generation subsystem is in a level electricity supply state or in an excess electricity supply state.

Exemplary claim 22: The electrical power generation system according to any one of exemplary claims 13 to 21 wherein the control subsystem comprises bypass branch valves operably coupled to the bypass branch.

Exemplary claim 23: The electric power generation system according to any one of exemplary claims 13 to 22 wherein the primary thermal energy input subsystem is a steam generator powered by nuclear fuel or fossil fuel.

Exemplary claim 24: The electric power generation system according to any one of exemplary claims 14 to 23, wherein the primary flow loop further comprises a primary condenser downstream of the primary turbine-generator and the auxiliary flow loop further comprises an auxiliary condenser downstream of the auxiliary turbine-generator, the primary condenser configured to form a condensed first working fluid from the first working fluid after the first working fluid exits the primary turbine-generator and the auxiliary condenser configured to form a condensed second working fluid from the second working fluid after the second working fluid exits the auxiliary turbine-generator.

Exemplary claim 25: The electric power generation system according to exemplary claim 24 wherein the primary flow loop further comprises a primary preheater downstream of the primary condenser, the primary preheater being fluidly coupled to the primary turbine-generator, and the auxiliary flow loop further comprises an auxiliary preheater downstream of the auxiliary condenser, the auxiliary preheater fluidly coupled to the auxiliary turbine-generator, the primary preheater configured to use a portion of the first working fluid flowing through the primary turbine-generator to add thermal energy to the condensed first working fluid and the auxiliary preheater configured to use a portion of the second working fluid flowing through the auxiliary turbine-generator to add thermal energy to the condensed second working fluid.

Exemplary claim 26: A method for operating an electric power generation system comprising: a) heating a first working fluid via a primary thermal energy input subsystem to form a heated first working fluid; and b) flowing a first portion of the heated first working fluid through a primary flow loop to a primary turbine-generator to extract thermal energy from the first portion of the first working fluid to generate electricity while flowing a second portion of the heated first working fluid through a bypass branch to heat a thermal mass composition in a thermal energy storage vessel.

Exemplary claim 27: The method according to exemplary claim 26 wherein step b) is performed upon the primary turbine-generator reaching an excess electricity supply state.

Exemplary claim 28: The method according to any one of exemplary claims 26 to 27 further comprising: c) upon the primary turbine-generator reaching a level electricity supply state or a deficient electricity supply state, stopping flow of the second portion of the heated first working fluid through the bypass branch and flowing an entirety of the heated first working fluid through the primary flow loop to the primary turbine-generator.

Exemplary claim 29: The method according to any one of exemplary claims 26 to 27 further comprising: d) upon the primary turbine-generator reaching a deficient electricity supply state, flowing a second working fluid through an auxiliary flow loop to the thermal energy storage vessel to transfer thermal energy from the thermal mass composition to the second working fluid to create a heated second working fluid and then flowing the heated second working fluid to an auxiliary turbine-generator.

Exemplary claim 30: An electric power generation system operably coupled to an electrical grid, the electric power generation system comprising: a primary flow loop comprising a thermal energy input subsystem and a primary turbine-generator, the primary flow loop configured to flow a first working fluid from the thermal energy input subsystem to the primary turbine-generator to generate electricity; a bypass branch fluidly coupled to a thermal energy storage subsystem, the bypass branch coupled to the primary flow loop downstream of the thermal energy input subsystem; an auxiliary flow loop comprising an auxiliary turbine-generator, the auxiliary flow loop passing through the thermal energy storage subsystem and configured to flow a second working fluid to the auxiliary turbine-generator to generate electricity; and a control subsystem operably coupled to the primary flow loop, the bypass branch, and the auxiliary flow loop, the control subsystem being configured to divert at least a portion of the first working fluid from the primary flow loop to the bypass branch when the electricity generated by the primary turbine-generator is in an excess electricity supply state.

Exemplary claim 31: A method for operating an electric power generation system comprising: a) flowing a first working fluid through a primary flow loop of a primary electric power generation subsystem configured to produce electricity via the first working fluid undergoing a first Rankine cycle in the primary flow loop; b) upon the primary electric power generation subsystem being in a excess electricity supply state, diverting at least a first portion of the first working fluid to a thermal energy storage to heat a thermal mass composition in a thermal energy storage vessel.

While the foregoing description and drawings represent exemplary embodiments of the present disclosure, it will be understood that various additions, modifications and substitutions may be made therein without departing from the spirit and scope and range of equivalents of the accompanying claims. In particular, it will be clear to those skilled in the art that the present invention may be embodied in other forms, structures, arrangements, proportions, sizes, and with other elements, materials, and components, without departing from the spirit or essential characteristics thereof. In addition, numerous variations in the methods/processes described herein may be made within the scope of the present disclosure. One skilled in the art will further appreciate that the embodiments may be used with many modifications of structure, arrangement, proportions, sizes, materials, and components and otherwise, used in the practice of the disclosure, which are particularly adapted to specific environments and operative requirements without departing from the principles described herein. The presently disclosed embodiments are therefore to be considered in all respects as illustrative and not restrictive. The appended claims should be construed broadly, to include other variants and embodiments of the disclosure, which may be made by those skilled in the art without departing from the scope and range of equivalents.

Claims

1. A method for operating an electric power generation system operably coupled to an electrical grid, the method comprising:

a) heating a first working fluid with a primary thermal energy input subsystem to form a heated first working fluid;

b) during a first mode of operation of the electric power generation system, flowing the heated first working fluid through a primary turbine-generator to extract thermal energy from the heated first working fluid to generate electricity for the electrical grid, the primary thermal energy input subsystem and the primary turbine-generator being part of a primary flow loop; and

c) during a second mode of operation of the electric power generation system, diverting a first portion of the heated first working fluid through a first fluid pathway of a thermal energy storage subsystem via a bypass branch before the primary turbine-generator, a thermal mass composition of the thermal energy storage subsystem absorbing thermal energy from the first portion of the heated first working fluid and storing the absorbed thermal energy.

2. The method according to claim 1 further comprising:

d) during a third mode of operation of the electric power generation system: d-1) flowing a substantial entirety of the heated first working fluid through the primary turbine-generator to extract thermal energy from the heated first working fluid to generate a first amount of electricity for the electrical grid; d-2) flowing a second working fluid through a second fluid pathway of the thermal energy storage subsystem so that the second working fluid absorbs the stored thermal energy from the thermal mass composition to form a heated second working fluid; and d-3) flowing the heated second working fluid through an auxiliary turbine-generator to extract thermal energy from the heated second working fluid to generate a second amount of electricity for the electrical grid, the second fluid pathway of the thermal energy storage subsystem and the auxiliary turbine-generator being part of an auxiliary flow loop.

3. The method according to claim 2, wherein the electric power generation system comprises a control subsystem, the control subsystem configured to select between the first, second, and third modes of operation based on an electricity demand of the electrical grid.

4. The method according to claim 3, wherein the control subsystem is configured to select between the first, second, and third modes of operation based on the electricity demand of the electrical grid relative to a maximum amount of electricity output that can be generated by the primary turbine-generator when the substantial entirety of the heated first working fluid flows through the primary flow loop.

5. The method according to claim 3, wherein the control subsystem is configured to:

operate the electric power generation system in the second mode when the primary turbine-generator is in an excess electricity supply state;

operate the electric power generation system in the third mode when the primary turbine-generator is in a deficient electricity supply state; and

operate the electric power generation system in the first mode when the primary turbine-generator is in a level electricity supply state.

6. The method according to claim 1, wherein step c) further comprises, during the second mode of operation of the electrical power generation system, flowing a remaining portion of the heated first working fluid through the primary turbine-generator to extract thermal energy from the remaining portion of the heated first working fluid to generate electricity.

7. The method according to claim 2, wherein the electric power generation system comprises a control subsystem, the control subsystem configured to select between the first and second modes of operation based on an electricity demand of the electrical grid relative to a maximum amount of electricity output that can be generated by the primary turbine-generator when the substantial entirety of the heated first working fluid flows through the primary flow loop; and wherein the control subsystem is configured to: (i) operate the electric power generation system in the first mode of operation when the primary turbine-generator is in a level electricity supply state; and (ii) operate the electric power generation system in the second mode of operation when the primary turbine-generator is in an excess electricity supply state.

8. The method according to claim 1, wherein step b) further comprises isolating the bypass branch from the primary flow loop to prevent flow of the heated first working fluid through the bypass branch.

9. The method according to claim 1, wherein the bypass branch comprises a bypass branch inlet fluidly coupled to the primary flow loop at a first position and a bypass branch outlet fluidly coupled to the primary flow loop at a second position, the first and second positions selected so that the first portion of the heated working fluid from the primary thermal energy input subsystem does not undergo expansion that drives the primary turbine-generator.

10. The method according to claim 1 wherein the first fluid pathway of the thermal energy storage subsystem comprises a first set of heat exchange tubes at least partially embedded in the thermal mass composition.

11. The method according to claim 2 wherein the first fluid pathway of the thermal energy storage subsystem comprises a first set of heat exchange tubes at least partially embedded in the thermal mass composition; wherein the second fluid pathway of the thermal energy storage subsystem comprises a second set of heat exchange tubes at least partially embedded in the thermal mass composition, the first and second sets of heat exchange tubes being fluidly isolated from one another; and wherein the thermal energy storage subsystem comprises an insulated vessel having an internal cavity containing the thermal mass composition.

12. (canceled)

13. An electric power generation system comprising:

a primary electric power generation subsystem comprising a primary flow loop containing a first working fluid, the primary flow loop comprising a primary thermal energy input subsystem configured to add thermal energy to a first working fluid flowing through the primary loop to form a heated first working fluid and a primary turbine-generator configured to extract thermal energy from the heated first working fluid to generate electricity;

a thermal energy storage subsystem containing a thermal mass composition;

a bypass branch comprising, in fluid coupling: a bypass branch inlet fluidly coupled to the primary flow loop to receive a first portion of the heated first working fluid before the primary turbine-generator; a first fluid pathway of the thermal energy storage subsystem configured to transfer thermal energy from the heated first working fluid flowing through the first fluid pathway to the thermal mass composition for storage; and a bypass branch outlet fluidly coupled to the primary flow loop downstream of the primary turbine-generator; and

a control subsystem configured to alternate between fluidly coupling and fluidly isolating the bypass branch to and from the primary flow loop based on an electricity demand of an electrical grid.

14. The electrical power generation system according to claim 13 further comprising an auxiliary electric power generation subsystem comprising an auxiliary turbine-generator, the auxiliary turbine-generator being part of an auxiliary flow loop which comprises a second fluid pathway of the thermal energy storage subsystem, the auxiliary flow loop configured to flow a second working fluid through the second fluid pathway of the thermal energy storage subsystem to absorb thermal energy from the thermal mass composition to form a heated second working fluid and then flow the heated second working fluid to the auxiliary turbine-generator to extract thermal energy from the heated second working fluid to generate electricity.

15. The electrical power generation system according to claim 14, wherein the bypass branch and the auxiliary flow loop are fluidly isolated from one another.

16. The electrical power generation system according to claim 14, wherein the first fluid pathway of the thermal energy storage subsystem is formed by a first set of heat exchange tubes at least partially embedded in the thermal mass composition; wherein the second fluid pathway of the thermal energy storage subsystem is formed by a second set of heat exchange tubes at least partially embedded in the thermal mass composition; and wherein the thermal energy storage subsystem comprises an insulated vessel having an internal cavity containing the thermal mass composition.

17. (canceled)

18. The electric power generation system according to claim 14, wherein the control subsystem is configured to activate the auxiliary electric power generation subsystem when the primary electric power generation subsystem is in a deficient electricity supply state.

19. The electric power generation system according to claim 13, wherein the control subsystem is configured to fluidly couple the bypass branch to the primary flow loop to allow the first portion of the heated first working fluid to flow through the bypass branch and heat the thermal mass composition when the primary electric power generation subsystem is in an excess electricity supply state.

20. The electric power generation system according to claim 13, wherein the control subsystem is configured to fluidly isolate the bypass branch from the primary flow loop to prevent the heated first working fluid from flowing through the bypass branch when the primary electric power generation subsystem is in a deficient electricity supply state or in a level electricity supply state.

21. The electric power generation system according to claim 14, wherein the control subsystem is configured to deactivate the auxiliary electric power generation subsystem when the primary electric power generation subsystem is in a level electricity supply state or in an excess electricity supply state.

22. (canceled)

23. (canceled)

24. (canceled)

25. (canceled)

26. (canceled)

27. (canceled)

28. (canceled)

29. (canceled)

30. (canceled)

31. A method for operating an electric power generation system comprising:

a) flowing a first working fluid through a primary flow loop of a primary electric power generation subsystem configured to produce electricity via the first working fluid undergoing a first Rankine cycle in the primary flow loop; and

b) upon the primary electric power generation subsystem being in an excess electricity supply state, diverting at least a first portion of the first working fluid to a thermal energy storage to heat a thermal mass composition in a thermal energy storage vessel.