Integration of waste heat with pumped thermal energy storage

Abstract

Disclosed herein is a technique by which the round trip efficiency ("RTE") of a pumped thermal energy storage system can be improved without generating a significant negative impact on the performance of a heat engine or heat pump at the cost of sacrificing the other. More specifically, the technique does not sacrifice the thermal efficiency of a heat engine (-) ) to increase the coefficient of performance ("COP") of the heat pump, and vice versa. The disclosed technology is achieved by using a low-temperature heat reservoir at a higher temperature than the power generation cycle during the charging process. The low-temperature heat reservoirs are "separated", i.e. Their temperature and utilization are independent of each other.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the following: U.S. Provisional Application No. 63 / 443,775, filed February 7, 2023, and U.S. Non-Provisional Patent Application No. 18 / 433,722, filed February 6, 2024, entitled “Integration of Waste Heat and Pumped Thermal Energy Storage”, with the same inventors, the contents of which are incorporated herein by reference for all purposes, including priority. Technical Field

[0003] This disclosure relates to a pumped thermal energy storage (“PTES”) system, and more specifically, to a technique for improving the round-trip efficiency (“RTE”) of a PTEES system. Background Technology

[0004] Pumped thermal energy storage (“PTES”) systems, also known as electrothermal energy storage systems, are used to store and generate energy. A PTES system typically consists of a configurable thermodynamic cycle in which thermal energy is transferred between a high-temperature heat reservoir and a low-temperature heat reservoir via a working fluid in a working fluid loop. A PTES typically operates in at least two cycles – a charging cycle and a power generation cycle. During the charging cycle, the PTES functions as a heat pump, and during the power generation cycle, it operates as a heat engine.

[0005] During the "charging" working cycle, the thermodynamic cycle (i.e., the nominally positive heat pump cycle) can be used to increase the thermal energy in the high-temperature heat storage. In some cases, an electric motor can be used to drive a compressor, which increases the pressure and temperature of the working fluid, thereby transferring and storing the thermal energy in the fluid in the high-temperature heat storage through the use of a high-temperature heat exchanger or through direct contact between the fluid and the heat medium in the heat storage. After heat is transferred to the high-temperature heat storage, the fluid can expand through a turbine, generating shaft work, which can be used to drive a gas compressor. This expansion of the working fluid reduces its pressure and temperature. After leaving the turbine, the working fluid can transfer heat from the low-temperature heat storage. The working fluid can then return to approximately its initial state (e.g., pressure and temperature).

[0006] In the "power generation" working cycle, the directions of fluid and heat circulation are reversed. A pump increases the pressure of the working fluid and moves it through a high-temperature heat exchanger or through direct contact between the fluid and the heat medium in the heat reservoir, transferring heat from the high-temperature heat reservoir to the working fluid. The heated working fluid expands through a turbine, generating shaft work. The turbine's shaft work may exceed the compressor's work, and the excess work can be converted into electrical energy by a generator and distributed to the power grid connected to the generator. After turbine expansion, the working fluid can be cooled by a cryogenic heat exchanger connected to a cryogenic heat reservoir before entering the pump. Upon leaving the cryogenic heat exchanger, the working fluid can return to approximately its initial state (i.e., pressure and temperature). Summary of the Invention

[0007] This document discloses a technique for improving the round-trip efficiency ("RTE") of a pumped thermal energy storage system by altering the coefficient of performance ("COP") and cycle efficiency (by changing the temperature ratio of each cycle). This is achieved by using two independent cryogenic reservoirs ("LTR") at different temperatures. More specifically, the disclosed technique achieves this by using a cryogenic reservoir with a temperature higher than that of the cryogenic reservoir during the charging process. The cryogenic reservoirs are "separate" and "independent" because their temperatures and utilization are independent of each other. Generally, the separate and independent reservoirs may also differ in terms of their independent reservoir media, reservoir locations, and heat exchangers.

[0008] Therefore, in a first aspect, a method for a pumped thermal energy storage system (“PTES”) includes: circulating a working fluid through a working fluid loop; and operating the PTES via a charging cycle and a power generation cycle while circulating the working fluid. During the charging cycle, heat is transferred from a first cryogenic reservoir to the working fluid, the first cryogenic reservoir operating at a first temperature. During the power generation cycle, heat is transferred from the working fluid to a second cryogenic reservoir, the second cryogenic reservoir existing independently of the first cryogenic reservoir, separated from the first cryogenic reservoir, and operating at a second temperature below the first temperature.

[0009] In a second aspect, the pumped thermal energy storage system (“PTES”) includes: a first cryogenic heat reservoir; a second cryogenic heat reservoir; and a working fluid loop through which the working fluid circulates during operation. The working fluid loop includes: during a charging cycle, a first cryogenic heat exchanger that transfers heat from the first cryogenic heat reservoir to the working fluid, the first cryogenic heat reservoir operating at a first temperature. During a power generation cycle, the working fluid loop includes a second cryogenic heat exchanger that transfers heat from the working fluid to the second cryogenic heat reservoir during operation. The second cryogenic heat reservoir exists independently of the first cryogenic heat reservoir, is separate from the first cryogenic heat reservoir, and operates at a second temperature below the first temperature.

[0010] In the third aspect, this paper presents and describes a pumped thermal energy storage system.

[0011] In the fourth aspect, this paper presents and describes a method for use in a pumped thermal energy storage system.

[0012] The foregoing provides a brief summary of the invention to offer a basic understanding of certain aspects of the invention. This summary is not an exhaustive overview of the invention. It is not intended to identify key or essential elements of the invention, nor to limit its scope. Its sole purpose is to provide some concepts in a simplified form as an introduction to the more detailed description discussed later. Attached Figure Description

[0013] This disclosure is best understood when read in conjunction with the accompanying drawings in the following detailed description. It should be emphasized that, in accordance with industry standard practice, the various features are not drawn to scale or shown in a simplified form. In fact, for clarity of discussion, the dimensions of the various features may be arbitrarily increased or decreased.

[0014] Figure 1A and Figure 1B PTEES systems in charging cycles and power generation cycles according to one or more embodiments are shown respectively.

[0015] Figure 2A and Figure 2B High-temperature heat exchangers comprising a high-temperature heat reservoir consisting of two fluid tanks and low-temperature heat exchangers comprising a low-temperature heat reservoir consisting of two fluid tanks are shown in some embodiments.

[0016] Figure 3A and Figure 3B A PTEES recycling system is shown in a charging cycle and a power generation cycle according to one or more embodiments.

[0017] Figure 4 It is based on one or more examples of this disclosure that can be used for configuration Figure 1A-Figure 1B and / or Figures 3A-3B The flow control system of the PTES system.

[0018] While the disclosed technology can have various modifications and alternatives, the accompanying drawings illustrate specific embodiments described in detail herein by way of example. However, it should be understood that the description of specific embodiments herein is not intended to limit the claims to the specific forms disclosed, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the appended claims. Detailed Implementation

[0019] Illustrative examples of the subject matter of the following claims will now be disclosed. For clarity, this specification does not describe all features of an actual implementation. It should be understood that during the development of any such actual implementation, many implementation-specific decisions may be made to achieve the developer's specific goals, such as complying with system-related and business-related constraints, which will vary from implementation to implementation. Furthermore, it should be understood that although such development work is complex and time-consuming, it is a routine task for those skilled in the art after reading this disclosure.

[0020] Therefore, in the charging cycle, heat is added to the working fluid from the low-temperature heat reservoir (“LTR”) and removed from the working fluid to the high-temperature heat reservoir (“HTR”). And, in the power generation cycle, heat is added to the working fluid from the high-temperature heat reservoir and removed from the working fluid to the low-temperature heat reservoir. PTEES systems typically use low-temperature heat resources to provide heat to the heat pump in the charging cycle. Typically, the same heat resource is used by the heat engine to dissipate heat in the power generation cycle. The heat resource can be stored in engineered heat reservoirs (e.g., closed heat reservoirs such as fluid tanks) or natural heat reservoirs (e.g., ambient air).

[0021] The quality factor of a heat pump is the coefficient of performance ("COP"), defined as the energy product (high-temperature heat, Q). h The quality factor of a heat engine is its thermal efficiency (η), defined as the ratio of the energy product (net work, W) to the energy cost (high-temperature heat, Q). h The ratio of COP to η. The overall quality factor of the PTES system is the round-trip efficiency (“RTE”), defined as the product of COP and η.

[0022] According to Carnot's principle, COP increases as the temperature ratio (Th / Tc) of the high-temperature and low-temperature reservoirs decreases. Conversely, η increases with decreasing T. h / T c Increases with increasing demand. In PTEES systems, heat pumps and heat engines typically share the same heat storage. Therefore, reducing T... h Or increase T c It is expected that COP will increase while η will decrease. Similarly, increasing T h Or lower T c It is expected that COP will decrease while η will increase. Overall, a change in heat sink temperature that is beneficial to the performance of one cycle will impair the performance of another cycle, thus reducing the overall impact on RTE.

[0023] A simplified numerical model of the PTES system can be considered, where the charging and power generation processes are represented by imperfect Carnot heat pumps and Carnot heat engines:

[0024]

[0025] The "C" factor represents the actual performance of the cycle relative to the Carnot ideal. The RTE can be expressed as the mathematical product of the two terms mentioned above:

[0026]

[0027] Because of T c,chg >T c,gen We can represent T c,chg =T c,gen +ΔT. Substitute into the above formula, and assume ΔT≤T h -T c,gen We can get

[0028]

[0029] For the baseline case, where ΔT = 0, RTE bl =C hp C gen ,so

[0030]

[0031] For example, in T h -T c,gen If the temperature of the charging heat source is 300K and the temperature of the charging heat source is 15K higher than that of the power generation heat source, the expected improvement in RTE is 5%, or from 60% to 63% of the baseline RTE.

[0032] An example of this is a PTEES system located in the same site as an existing closed-cycle power plant. Most closed-cycle power plants, such as nuclear power plants, coal-fired power plants, concentrated solar power plants, or combined cycle gas turbine power plants, use steam as the working fluid to convert high-temperature thermal energy into mechanical energy and generate electricity using turbines. To end the steam cycle, the low-pressure steam at the turbine exhaust port must condense back into a liquid state.

[0033] The heat recovered from this process is typically at a temperature below the steam turbine inlet temperature, but at least 15°C or more higher than the ambient air temperature, in order to transfer waste heat to the surrounding environment. In the published concept, a PTE system would utilize this waste heat as a heat source during the charging process. Later, the PTE system would generate electricity and release heat into the surrounding environment, thus achieving a higher RTE than a standalone PTE system that charges from surrounding resources.

[0034] Power plants can be a source of waste heat, with potential sources including turbine condensate or cooling tower water. In addition, many industrial plants (such as oil refineries, paper mills, and cement plants) have significant waste heat sources. Broadly speaking, if the waste heat source is warmer than the surrounding air, a PTE system can utilize it to increase COP without compromising η, resulting in a net increase in RTE.

[0035] For power plants using steam cycles in cold climates, the impact can be even greater than in the previous examples. If the heat source temperature comes from the steam condenser, the temperature is constant to avoid ice buildup in the cooling tower, and the lower ambient temperature will increase ΔT even more. Another benefit is that extracting heat from the heat source can also reduce parasitic cooling loads (e.g., cooling tower fan operation) on the steam cycle.

[0036] Now turn to the attached image. Figure 1A and Figure 1B The PTEES system 100 is shown during charging cycle 103 and power generation cycle 106, respectively. Those skilled in the art will understand that although shown in two different figures, Figure 1A Charging cycle 103 and Figure 1B The power generation cycle 106 in the system represents two different configurations of a single PTES system 100 (not shown otherwise). This configuration includes controlling the flow rate of the working fluid through the working fluid loop by operating a flow control valve in a manner more fully disclosed below.

[0037] Those skilled in the art should understand that Figure 1A and Figure 1B Some details have been omitted. For example, any particular implementation will include various sensors to measure, for example, temperature, pressure, and flow rate at various points in the working fluid circuit. Omitted features may also include inlets, outlets, pressure relief valves, and power connections. These omitted features are common and well-known in the art and can be routinely implemented. Therefore, those skilled in the art will recognize their applicability and readily implement these omitted details upon reading this disclosure. Therefore, these details have been omitted for clarity and to avoid obscuring the claims made below.

[0038] Now back Figure 1A In the charging cycle 103, the working fluid circuit 109a includes a low-temperature heat exchange 112, a compression process 115, a high-temperature heat exchange 118, and an expansion process 121. When the PTE S100 is in this configuration, it can be referred to as a "heat pump". This configuration of the working fluid circuit 109 can be referred to as the "charging configuration" or "heat pump configuration" of the PTE S100. The working fluid in the embodiments shown in this specification is carbon dioxide (CO2), but alternative embodiments may use alternative working fluids.

[0039] The compression process 115 is downstream of the cryogenic heat exchange 112 and upstream of the high-temperature heat exchange 118. Among other functions, the compression process 115 provides the power to circulate the working fluid through the working fluid circuit 109a during the charging cycle 103. The compression process 115 revolves around the operation of the compression device 124. The compression device 124 may be a compressor. Examples of suitable compressors include, but are not limited to, reciprocating compressors, centrifugal compressors, and scroll compressors. Those skilled in the art will recognize upon reading this disclosure that other types of compressors may be applicable to various embodiments, including devices with equivalent structures performing the disclosed functions. The compression process 115 receives the working fluid from the cryogenic exchange 112, compresses the working fluid to increase its temperature and pressure, and discharges the working fluid to the high-temperature heat exchange 118.

[0040] The expansion process 121 is downstream of the high-temperature heat exchange 118 and upstream of the low-temperature heat exchange 112. The expansion process 121 revolves around the operation of an expansion device 127 (e.g., an expander). Examples of suitable expanders include, but are not limited to, adiabatic expansion valves or mechanical expanders, depending on the embodiment. A mechanical expander may be, for example, a turbine. Those skilled in the art will recognize upon reading this disclosure that other types of expanders may be applicable to various embodiments, including devices with equivalent structures performing the disclosed functions. The expansion process 121 receives working fluid from the high-temperature exchange 118, expands the working fluid to reduce its temperature and pressure, and discharges the working fluid to the low-temperature exchange 112.

[0041] High-temperature heat exchange 118 facilitates heat exchange between the working fluid and the high-temperature heat storage HTRc. A first exchange medium (not shown separately) circulates between the high-temperature heat storage HTRc and the high-temperature heat exchanger HTXc. The first exchange medium circulates through a line 130 on a first side 133 of the high-temperature heat exchanger HTXc. The working fluid enters the high-temperature heat exchanger HTXc from the compression process 115 and exits from the second side 136 of the high-temperature heat exchanger HTXc to the expansion process 121. In the high-temperature heat exchanger HTXc, heat is exchanged from the working fluid to the first exchange medium and stored in the high-temperature heat storage HTRc.

[0042] A high-temperature thermal storage unit (HTRc) may be a designed, closed thermal storage unit, much like a fluid tank. A closed thermal storage unit may include a heat transfer medium, such as sand or gravel, concrete, encapsulated phase change material, bulk phase change material, or a combination thereof. Notably, in some embodiments, the high-temperature thermal storage unit (HTRc) may include two fluid tanks, HTR1 and HTR2, such as... Figure 2A As shown.

[0043] The cryogenic heat exchanger 112 exchanges heat between the working fluid and the cryogenic heat storage unit LTRc. A second exchange medium (not shown separately) circulates between the cryogenic heat storage unit LTRc and the cryogenic heat exchanger LTXc. The second exchange medium circulates through a line 139 on one side 142 of the cryogenic heat exchanger LTXc. The working fluid enters the cryogenic heat exchanger LTXc from the expansion process 121 and exits from its second side 145 to the compression process 115. In the cryogenic heat exchanger LTXc, heat from the cryogenic heat storage unit LTRc is exchanged from the second exchange medium to the working fluid.

[0044] A cryogenic thermal storage unit (LTRc) can be an engineered thermal storage unit or a natural thermal storage unit. If carefully designed, a cryogenic thermal storage unit (LTRc) may be a closed thermal storage unit, like a fluid tank. A closed thermal storage unit may include a heat transfer medium, such as sand or gravel, concrete, encapsulated phase change material, bulk phase change material, or a combination thereof. If it is a natural thermal storage unit, the cryogenic thermal storage unit (LTRc) may be, for example, an ambient atmosphere or a geothermal storage unit. Notably, in some embodiments, the cryogenic thermal storage unit (LTRc) may include two fluid tanks, LTR1 and LTR2, such as... Figure 2B As shown.

[0045] In the illustrated embodiment, the cryogenic heat reservoir LTRc can alternatively be a waste heat source—i.e., heat generated by another process. Waste heat sources can include waste heat, low-value heat, or low-grade heat, or heat from other processes that has a minor impact on the original process but is not entirely waste heat. For example, a power plant can be a waste heat source in its turbine exhaust stream. Possible source locations in a power plant might include turbine condensate or cooling tower water. Furthermore, many industrial plants (such as oil refineries, paper mills, and cement plants) have significant waste heat sources. This waste heat can be captured from the medium that can be used in the cryogenic heat reservoir LTRc in the illustrated embodiment.

[0046] In the illustrated embodiment, the cryogenic heat storage unit (LTRc) can be the ambient atmosphere. As mentioned above, broadly speaking, if the waste heat source is warmer than the ambient air, the PTE system can utilize it to increase the Co-op without compromising η, resulting in a net increase in RTE. Therefore, in the illustrated embodiment, the ambient atmosphere is colder than the waste heat source (and has less thermal energy). In some embodiments, the ambient atmosphere temperature may be 5°C or more lower than the waste heat source.

[0047] Refer again Figure 1ADuring the “charging” operating cycle, the thermal energy in the high-temperature heat reservoir increases. Compression process 115 increases the pressure and temperature of the working fluid. High-temperature heat exchange 118 transfers thermal energy to the high-temperature heat reservoir HTRc and stores it. After the heat is transferred to the high-temperature heat reservoir HTRc, the working fluid expands through expansion process 121, thereby reducing the pressure and temperature of the working fluid. After leaving expansion process 121, the working fluid passes through low-temperature heat exchange 112. Low-temperature heat exchange 112 transfers heat from the low-temperature heat reservoir LTRc to the working fluid. After leaving low-temperature heat exchange 112, the working fluid returns to approximately its initial state (e.g., pressure and temperature).

[0048] Now back Figure 1B In the power generation cycle 106, the working fluid loop 109b includes a low-temperature heat exchange 150, a compression process 153, a high-temperature heat exchange 156, and an expansion process 159. In this configuration, the PTES100 operates as a heat engine. This configuration of the working fluid loop 109b may be referred to as the "power generation configuration," "emission configuration," or "heat engine configuration" of the PTES100. The working fluid in the embodiments shown in this specification is still carbon dioxide (CO2), but alternative embodiments may use alternative working fluids.

[0049] The compression process 153 is downstream of the low-temperature heat exchange 150 and upstream of the high-temperature heat exchange 156. Among other functions, the compression process 153 provides the power to circulate the working fluid through the working fluid circuit 109b during the power generation cycle 106. The compression process 153 is performed in relation to the operation of the compression unit 162.

[0050] Compression device 162 may be a pump or a gas-phase compressor. Examples of suitable compression devices include, but are not limited to, centrifugal pumps, positive displacement pumps, centrifugal compressors, and axial flow compressors. Those skilled in the art will recognize upon reading this disclosure that other types of compression devices may be applicable to various embodiments, including devices with equivalent structures performing the disclosed functions. Compression process 153 receives working fluid from cryogenic exchange 150, compresses the working fluid to increase its temperature and pressure, and discharges the working fluid to high-temperature heat exchange 156.

[0051] The expansion process 159 is downstream of the high-temperature heat exchange 156 and upstream of the low-temperature heat exchange 150. The expansion process 159 takes place around the operation of an expansion device 165 (e.g., an expander). Examples of suitable expanders include, but are not limited to, mechanical expanders, depending on the embodiment. A mechanical expander may be, for example, a turbine. Those skilled in the art will recognize upon reading this disclosure that other types of expanders may be applicable to various embodiments, including devices with equivalent structures performing the disclosed functions. The expansion process 159 receives working fluid from the high-temperature exchange 156, expands the working fluid to reduce its temperature and pressure, and discharges the working fluid to the low-temperature exchange 150.

[0052] High-temperature heat exchange 156 facilitates heat exchange between the working fluid and the high-temperature heat storage HTRg. A first exchange medium (not shown separately) circulates between the high-temperature heat storage HTRg and the high-temperature heat exchanger HTXg. The first exchange medium circulates through a line 168 on a first side 171 of the high-temperature heat exchanger HTXg. The working fluid enters the high-temperature heat exchanger HTXg from the compression process 153 and exits from the second side 173 of the high-temperature heat exchanger HTXg to the expansion process 159. In the high-temperature heat exchanger HTXg, heat is exchanged from the high-temperature heat storage HTRg to the working fluid via the first exchange medium.

[0053] A high-temperature thermal storage unit (HTRg) can be a designed, closed thermal storage unit, much like a fluid tank. The closed thermal storage unit can include a heat transfer medium, such as sand or gravel, concrete, encapsulated phase change material, bulk phase change material, or a combination thereof. Notably, in some embodiments, the high-temperature thermal storage unit (HTRg) can include two fluid tanks, HTR1 and HTR2, like... Figure 2A It is the same as the high-temperature heat storage HTRc shown for charging cycles.

[0054] The cryogenic heat exchanger 150 exchanges heat between the working fluid and the cryogenic heat storage unit LTRg. A second exchange medium (not shown separately) circulates between the cryogenic heat storage unit LTRg and the cryogenic heat exchanger LTXg. The second exchange medium circulates through a line 174 on one side 177 of the cryogenic heat exchanger LTXg. The working fluid enters the cryogenic heat exchanger LTXg from the expansion process 159 and exits from its second side 180 to the compression process 153. In the cryogenic heat exchanger LTXg, heat from the working fluid is exchanged from the second exchange medium to the cryogenic heat storage unit LTRg.

[0055] The cryogenic thermal storage unit (LTRg) may be an engineered thermal storage unit or a natural thermal storage unit. If the design is successful, the cryogenic thermal storage unit LTRg can be a closed thermal storage unit, such as a fluid tank, or it can be some kind of fluid flow. A closed thermal storage unit may include a heat medium, such as sand or gravel, concrete, encapsulated phase change material, bulk phase change material, or a combination thereof. If it is a natural thermal storage unit, the cryogenic thermal storage unit LTRg may be, for example, an ambient atmosphere or a geothermal storage unit. Notably, in some embodiments, the cryogenic thermal storage unit LTRg may include two fluid tanks, LTR1 and LTR2, such as... Figure 2B As shown, the low-temperature thermal storage LTRc is used in the charging cycle.

[0056] In the illustrated embodiment, the low-temperature heat reservoir LTRg can be either ambient air or a geothermal reservoir. As mentioned above, broadly speaking, if the waste heat source is warmer than the ambient air, the PTE system can utilize it to increase the COP without compromising η, resulting in a net increase in RTE. Therefore, in the illustrated embodiment, the ambient air is cooler than the waste heat source. In some embodiments, the ambient air temperature may be 5°C or more lower than the waste heat source.

[0057] In the "power generation" working cycle, the direction of fluid and heat circulation is opposite to that of the charging cycle discussed above. Compression process 153 increases the pressure of the working fluid and moves it through high-temperature heat exchange 156, which transfers heat from the high-temperature heat reservoir to the working fluid. The heated working fluid can expand through expansion process 159, for example, by generating shaft work through a turbine. The shaft work of the turbine may exceed the work of the compressor, and the excess work can be converted into electrical energy by a generator and distributed to the power grid connected to the generator. After expansion process 159, the working fluid can be cooled through low-temperature heat exchange 150 connected to low-temperature heat reservoir LTRg, and then enters compression process 153 (e.g., a pump). After leaving low-temperature heat exchange 150, the working fluid can return to approximately its initial state (i.e., pressure and temperature).

[0058] As described below, the cryogenic thermal storage units LTRc and LTRg are "separate," "independent," and operate at different temperatures. The cryogenic thermal storage units LTRc and LTRg are "separate" and "independent" because their temperatures and utilization are independent of each other. Generally, the separate and independent thermal storage units may also differ in terms of their individual thermal storage media, thermal storage locations, and heat exchangers. More specifically, the second temperature of the cryogenic thermal storage unit LTRg during the power generation cycle is at least about 5°C lower than the first temperature of the cryogenic thermal storage unit LTRc during the charging cycle. In some embodiments, the second temperature is about 15°C lower than the first temperature. Some embodiments may exhibit even larger temperature differences.

[0059] Therefore, refer to Figure 1A and Figure 1B(Combined), the PTES100 includes a first cryogenic heat reservoir LTRc; a second cryogenic heat reservoir LTRc; and working fluid circuits 109a and 109b through which the working fluid circulates during operation. Working fluid circuit 109a includes a first cryogenic heat exchanger LTXc, which transfers heat from the first cryogenic heat reservoir LTRc to the working fluid during charging cycle 103, the first cryogenic heat reservoir LTRc operating at a first temperature. During power generation cycle, working fluid circuit 109b includes a second cryogenic heat exchanger LTXg, which transfers heat from the working fluid to the second cryogenic heat reservoir LTRg during operation. The second cryogenic heat reservoir LTRg is separate from the first cryogenic heat reservoir LTRc and operates at a second temperature below the first temperature.

[0060] Furthermore, the method for using the PTES100 includes: circulating the working fluid through working fluid loops 109a and 109b, and operating the PTES100 through a charging cycle 103 and a power generation cycle 106 while circulating the working fluid. During the charging cycle 103, heat is transferred from a first cryogenic heat storage tank LTRc to the working fluid, the first cryogenic heat storage tank LTRc operating at a first temperature. In the power generation cycle, heat is transferred from the working fluid to a second cryogenic heat storage tank LTRg, the second cryogenic heat storage tank LTRg being separate from the first cryogenic heat storage tank LTRc and operating at a second temperature below the first temperature.

[0061] Those skilled in the art will understand the additional embodiments not shown in the accompanying drawings after reading this disclosure. For example, the embodiments shown herein utilize a heat exchanger for heat exchange. However, as mentioned above, some embodiments may omit the heat exchanger and achieve heat exchange through direct contact between the heat medium in the heat reservoir and the working fluid. Furthermore, this change eliminates the exchange medium in the illustrated embodiments because the heat exchange is direct rather than indirect. This may be the case, depending on the embodiment, for one or both of high-temperature and low-temperature heat exchange. It may also be the case in one or both of the charging and power generation cycles.

[0062] For example, Figure 1A-Figure 1B The PTES100 is not a recycler PTES, meaning there is no recycler in this design. Figure 3A and Figure 3BThe recovered PTES 300 is shown in charging cycle 303 and power generation cycle 306, respectively. The recovered PTES adds an internal heat exchanger to the working fluid loops 309a and 309b to transfer heat after (in working fluid loop 309a) or before (in working fluid loop 309b) the high-temperature heat exchanger (“HTX”), thereby preheating (in working fluid loop 309a) or precooling (in working fluid loop 309b) the fluid flowing out (in working fluid loop 309a) or into (in working fluid loop 309b) the low-temperature heat exchanger (“LTX”).

[0063] This internal heat exchanger is a "recovery unit" ("RCX"). By preheating the fluid medium, a higher post-compressor temperature can be achieved at a reasonable pressure ratio. The recovery-type PTES 300 includes a recovery unit RCXc in a charging cycle 303 and a recovery unit RCXg in a power generation cycle 306. It should be noted that in most embodiments, the recovery unit RCXc in the charging cycle 303 and the recovery unit RCXg in the power generation cycle 306 can be implemented using the same physical device. Figures 3A-3B The PTES 300 includes many features related to Figure 1A-Figure 1B The PTES100 is a similar component, and similar components have the same markings.

[0064] As mentioned above, Figure 1A The charging cycle shown and Figure 1B The configuration of the working fluid loops 109a and 109b between the power generation cycles shown can be controlled by fluid flow valves. Although such a control system is readily apparent to those skilled in the art, for the sake of completeness, Figure 4 Such a control system 400 is shown. The control system 400 may include a plurality of fluid flow valves 405 and a controller 410 that transmits control signals via wires 415.

[0065] Controller 410 includes processor-based resource 420, which may be, for example, but not limited to, a microcontroller, microprocessor, application-specific integrated circuit (“ASIC”), electrically erasable programmable read-only memory (“EEPROM”), etc. Depending on the implementation of the processor-based resource, controller 410 may also include memory 425, in which instructions (not shown) are encoded, executable by processor-based resource 420, to implement the functions of controller 410. Similarly, depending on the implementation of processor-based resource 420, memory 425 may be part of processor-based resource 420 or a separate device. For example, the instructions may be firmware stored in a memory portion of a microprocessor, or routines stored in a separate read-only or random access memory chip. Similarly, in some embodiments of processor-based resource 420 (e.g., ASIC), memory 435 may be omitted entirely.

[0066] Now for reference Figures 1A to 1B and Figure 4 (Combination), such as the controller 410, can be used to configure Figure 1A The charging cycle shown and Figure 1B The diagram shows working fluid loops 109a and 109b between the power generation cycles. The controller 410 can send control signals to the fluid flow valve 405 to control the working fluid flow rate. Therefore, to configure working fluid loop 109a for charging cycle 103, the controller 410 controls the fluid flow valve 405 to direct the working fluid to compression process 115 and expansion process 121, while simultaneously diverting the working fluid away from expansion process 159 and compression process 153. Conversely, to configure working fluid loop 109b for power generation cycle 106, the controller 410 controls the fluid flow valve 405 to direct the working fluid to expansion process 159 and compression process 153, while simultaneously diverting the working fluid away from compression process 115 and expansion process 127.

[0067] It is important to note that, according to the usage in this art, the terms "high temperature" and "low temperature" in "high-temperature heat exchange" and "low-temperature heat exchange" are defined relative to each other. That is, the term indicates that the temperature at which the heat exchange occurs in a "high-temperature heat exchange" is higher than the temperature at which the heat exchange occurs in a "low-temperature heat exchange." Some embodiments may perform high-temperature heat exchange at 350°C and low-temperature heat exchange at 20°C, with a temperature difference (a / k / a approximate temperature) of about 5°C. However, for any given embodiment, quantifying the temperatures at which these heat exchanges occur will be an implementation-specific detail, just as the temperature difference between the temperatures at which these heat exchanges occur is. In phrases referring to equipment, such as "low-temperature heat exchanger," "low-temperature heat storage," "high-temperature heat exchanger," and "high-temperature heat storage," these terms indicate a specific heat exchange using the equipment.

[0068] Furthermore, the terms "low-temperature heat exchange" and "high-temperature heat exchange" superficially imply a single temperature. Those skilled in the art will recognize upon reading this disclosure that different temperatures may exist at various points in the heat exchange. For example, the temperature at the heat exchange inlet may be one temperature, the temperature of the medium may be a second temperature, and the temperature at the outlet may be a third temperature. However, in accordance with practice in the art, for practical purposes in operation and discussion, a heat exchange may be represented or conceptualized as a single temperature. When referring to such a single temperature, this disclosure generally refers to the temperature at which the medium enters the corresponding heat exchanger from the storage tank.

[0069] The use of vague terms such as "about" or "approximately" when referring to any quantity in this specification indicates that a certain deviation from the stated quantity is permissible, provided that the actual quantity is within a certain margin of error and the overall system operates at the expected efficiency level. For example, as mentioned above, the temperature difference during low-temperature heat exchange in a power generation cycle may be at least about 5°C lower than the temperature difference during low-temperature heat exchange in a charging cycle. However, due to operating conditions, differences of ±0.1°C or greater may occur, such that the difference may be only 4.9°C or less. Such deviations are permissible as long as the overall system operates at a certain efficiency level. The same applies to any other quantity discussed or disclosed herein.

[0070] Therefore, according to the technology disclosed herein, the first cryogenic heat reservoir (i.e., the cryogenic heat reservoir for the charging cycle) exists independently, separately, and operates at a higher temperature relative to the second cryogenic heat reservoir (i.e., the cryogenic heat reservoir for the power generation cycle). One or both of the first and second cryogenic heat reservoirs can be engineered sources or natural heat reservoirs. Engineered sources can be, for example, closed heat reservoirs or heat sources from waste (e.g., low-grade or low-value) from another process. Natural heat reservoirs can be, for example, ambient atmosphere or geothermal sources.

[0071] Therefore, in a first embodiment, a method for a pumped thermal energy storage system (“PTES”) includes circulating a working fluid through a working fluid loop; and operating the PTES through a charging cycle and a power generation cycle while the working fluid is circulated. During the charging cycle, heat is transferred from a first cryogenic reservoir to the working fluid, the first cryogenic reservoir operating at a first temperature. During the power generation cycle, heat is transferred from the working fluid to a second cryogenic reservoir. The second cryogenic reservoir exists independently of the first cryogenic reservoir, is separate from the first cryogenic reservoir, and operates at a second temperature below the first temperature.

[0072] In the second embodiment, the second temperature in the first embodiment is lower than the first temperature by more than about 5°C.

[0073] In the third embodiment, the second temperature in the second embodiment is about 15°C lower than the first temperature.

[0074] In the fourth embodiment, the working fluid in the first embodiment is carbon dioxide (CO2).

[0075] In the fifth embodiment, the first low-temperature heat storage in the first embodiment is a waste heat source, while the second low-temperature heat storage is the ambient atmosphere.

[0076] In the sixth embodiment, the first embodiment further includes a working fluid loop configured for charging and power generation cycles.

[0077] In the seventh embodiment, the charging cycle of the first embodiment further includes: exchanging heat between the working fluid and the first high-temperature heat storage tank; a compression process downstream of the low-temperature heat exchange and upstream of the high-temperature heat exchange; and an expansion process downstream of the high-temperature heat exchange and upstream of the low-temperature heat exchange. Furthermore, the power generation cycle further includes: exchanging heat between the working fluid and the first high-temperature heat storage tank; an expansion process downstream of the high-temperature heat exchange and upstream of the low-temperature heat exchange; and a compression process upstream of the high-temperature heat exchange and downstream of the low-temperature heat exchange.

[0078] In the eighth embodiment, the seventh embodiment further includes recovering heat from the working fluid during the charging cycle and the power generation cycle.

[0079] In the ninth embodiment, the first embodiment further includes recovering heat from the working fluid during the charging cycle and the power generation cycle.

[0080] In a tenth embodiment, the pumped thermal energy storage system (“PTES”) includes: a first cryogenic heat reservoir; a second cryogenic heat reservoir; and a working fluid loop through which the working fluid circulates during operation. The working fluid loop includes: during a charging cycle, a first cryogenic heat exchanger that transfers heat from the first cryogenic heat reservoir to the working fluid, the first cryogenic heat reservoir operating at a first temperature. During a power generation cycle, the working fluid loop includes a second cryogenic heat exchanger that transfers heat from the working fluid to the second cryogenic heat reservoir during operation. The second cryogenic heat reservoir exists independently of the first cryogenic heat reservoir, is separate from the first cryogenic heat reservoir, and operates at a second temperature below the first temperature.

[0081] In the eleventh embodiment, the second temperature in the tenth embodiment is more than about 5°C lower than the first temperature.

[0082] In the twelfth embodiment, the second temperature in the eleventh embodiment is about 15°C lower than the first temperature.

[0083] In the thirteenth embodiment, the working fluid of the tenth embodiment is carbon dioxide (CO2).

[0084] In the fourteenth embodiment, the first low-temperature heat storage in the tenth embodiment is a waste heat source, while the second low-temperature heat storage is the ambient atmosphere.

[0085] In the fifteenth embodiment, the tenth embodiment also includes a control system programmed to configure working fluid loops for charging and power generation cycles.

[0086] In the sixteenth embodiment, the control system of the fifteenth embodiment includes: a plurality of fluid flow valves; a processor-based resource; and a memory. A plurality of instructions reside in the memory, which, when executed by the processor-based resource, cause the processor-based resource to configure working fluid loops for charging and power generation cycles.

[0087] In the seventeenth embodiment, the working fluid circuit of the tenth embodiment further includes, during the charging cycle: a high-temperature heat exchange between the working fluid and the first high-temperature heat reservoir; a compression process downstream of the low-temperature heat exchange and upstream of the high-temperature heat exchange; and an expansion process downstream of the high-temperature heat exchange and upstream of the low-temperature heat exchange. During the power generation cycle, the working fluid circuit includes: a high-temperature heat exchange between the working fluid and the first high-temperature heat reservoir; an expansion process downstream of the high-temperature heat exchange and upstream of the low-temperature heat exchange; and a compression process upstream of the high-temperature heat exchange and downstream of the low-temperature heat exchange.

[0088] In the eighteenth embodiment, the seventeenth embodiment further includes a heat recovery unit for recovering heat from the working fluid in the charging cycle and the power generation cycle during operation.

[0089] In the nineteenth embodiment, the high-temperature heat storage of the seventeenth embodiment is a closed heat storage containing a heat medium selected from the group consisting of sand or gravel, concrete, encapsulated phase change material, bulk phase change material, or combinations thereof.

[0090] In the twentieth embodiment, the tenth embodiment further includes a heat recovery unit for recovering heat from the working fluid in the charging cycle and the power generation cycle during operation.

[0091] In the twenty-first embodiment, a pumped thermal energy storage system (“PTES”) is shown and described above.

[0092] In the twenty-second embodiment, a method for use in a pumped thermal energy storage system (“PTES”) is shown and described above.

[0093] Furthermore, the article “a(a)” as used herein is intended to have the usual meaning in the patent art, namely “one or more”. In this document, the word “about” when used with numerical values ​​generally indicates within the tolerances of the equipment used to produce that value, or in some instances, indicates plus or minus 10%, or plus or minus 5%, or plus or minus 1%, unless otherwise expressly stated. Additionally, the term “substantially” as used herein means the majority, or almost all, or all, or, for example, the range of about 51% to about 100%. Furthermore, the examples in this document are for illustrative purposes only and are presented for discussion purposes and not for limiting purposes.

[0094] The examples in this disclosure can also be directed to non-transitory computer-readable media that store computer-executable instructions and are executed by one or more processors of a computer that accesses the computer-readable medium. A computer-readable medium can be any available medium that is accessible to a computer. For example, such a computer-readable medium may include random access memory (“RAM”); read-only memory (“ROM”); electrically erasable, programmable, read-only memory (“EEPROM”); optical disc read-only memory (“CD-ROM”) or other optical disc storage, disk storage or other magnetic storage device, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and is accessible to a computer. Disks and optical discs as used herein include compact optical discs (“CD”), laser discs, optical discs, digital versatile optical discs (“DVD”), floppy disks, and... Optical discs, unlike magnetic disks which typically reproduce data magnetically, use lasers to reproduce data optically.

[0095] It should also be noted that the software implementation aspects of the subject matter claimed below are typically encoded on some form of program storage medium or implemented via some type of transmission medium. The program storage medium is a non-transitory medium and can be magnetic (e.g., floppy disk or hard disk) or optical disk (e.g., optical disk (read-only memory, or "CD-ROM")), which can be read-only or random access. Similarly, the transmission medium can be twisted pair, coaxial cable, optical fiber, or some other suitable transmission medium known in the art. The claimed subject matter is not limited to these aspects of any given implementation.

[0096] For purposes of explanation, specific terminology has been used in the foregoing description to provide a full understanding of this disclosure. However, those skilled in the art will understand that specific details are not required to practice the systems and methods described herein. The above description of specific examples is for illustrative and descriptive purposes only. They are not intended to be exhaustive or to limit the disclosure to the specific forms described. It will be apparent that many modifications and variations are possible in light of the foregoing teachings. These examples are shown and described in order to best explain the principles and practical application of this disclosure, thereby enabling those skilled in the art to best utilize this disclosure and the various examples, and to make various modifications to suit a particular intended use. The scope of this disclosure is intended to be defined by the claims and their equivalents.

Claims

1. A method for pumping thermal energy storage system ("PTES"), the method comprising: The working fluid is circulated through the working fluid loop; as well as PTES is operated through a charging cycle and a power generation cycle while the working fluid is circulated, wherein: During the charging cycle, heat is transferred from the first cryogenic heat reservoir to the working fluid, the first cryogenic heat reservoir operating at a first temperature; as well as During the power generation cycle, heat is transferred from the working fluid to a second cryogenic heat storage tank, wherein the second cryogenic heat storage tank is: It exists independently of the first low-temperature thermal storage facility; It is separated from the first low-temperature thermal storage; as well as It operates at a second temperature lower than the first temperature.

2. The method as described in claim 1, wherein, The second temperature is lower than the first temperature by more than about 5°C.

3. The method as described in claim 2, wherein, The second temperature is about 15°C lower than the first temperature.

4. The method of claim 1, wherein, The working fluid is carbon dioxide (CO2).

5. The method of claim 1, wherein: The first low-temperature heat storage is a waste heat source; and The second low-temperature thermal storage is in the ambient atmosphere.

6. The method of claim 1, further comprising configuring the working fluid circuit for the charging cycle and the power generation cycle.

7. The method of claim 1, wherein: The charging cycle also includes: Heat is exchanged between the working fluid and the first high-temperature heat storage; The compression process downstream of the low-temperature heat exchange and upstream of the high-temperature heat exchange; and The expansion process downstream of the high-temperature heat exchange and upstream of the low-temperature heat exchange; and The power generation cycle also includes: Heat is exchanged between the working fluid and the first high-temperature heat storage; The expansion process downstream of the high-temperature heat exchange and upstream of the low-temperature heat exchange; and The compression process upstream of the high-temperature heat exchange and downstream of the low-temperature heat exchange.

8. The method of claim 7, further comprising recovering heat from the working fluid during the charging cycle and the power generation cycle.

9. The method of claim 1, further comprising recovering heat from the working fluid during the charging cycle and the power generation cycle.

10. A pumped thermal energy storage system ("PTES"), comprising: First low-temperature thermal storage; Second low-temperature thermal storage; as well as Working fluid circuit, through which working fluid circulates during operation, the working fluid circuit comprising: During the charging cycle, a first cryogenic heat exchanger, which transfers heat from the first cryogenic heat reservoir to the working fluid during operation, the first cryogenic heat reservoir operating at a first temperature; as well as During the power generation cycle, a second cryogenic heat exchanger transfers heat from the working fluid to a second cryogenic heat storage unit, which in turn: It exists independently of the first low-temperature thermal storage facility; It is separated from the first low-temperature thermal storage; as well as It operates at a second temperature lower than the first temperature.

11. The PTES of claim 10, wherein the second temperature is lower than the first temperature by more than about 5°C.

12. The PTES of claim 11, wherein the second temperature is about 15°C lower than the first temperature.

13. The PTES of claim 10, wherein the working fluid is carbon dioxide (CO2).

14. The PTES as claimed in claim 10, wherein: The first low-temperature heat storage is a waste heat source; and The second low-temperature thermal storage is in the ambient atmosphere.

15. The PTES of claim 10, further comprising a control system programmed to configure the working fluid loop for the charging cycle and the power generation cycle.

16. The PTES of claim 15, wherein the control system comprises: Multiple fluid flow valves Processor-based resources; as well as A memory resident thereon, wherein when the instructions are executed by the processor-based resources, the processor-based resources are configured for the working fluid loops of the charging cycle and the power generation cycle.

17. The PTES of claim 10, wherein the working fluid circuit further comprises: In the charging cycle: High-temperature heat exchange between the working fluid and the first high-temperature heat storage; The compression process downstream of the low-temperature heat exchange and upstream of the high-temperature heat exchange; as well as The expansion process downstream of the high-temperature heat exchange and upstream of the low-temperature heat exchange; as well as In the power generation cycle: High-temperature heat exchange between the working fluid and the first high-temperature heat storage; The expansion process downstream of the high-temperature heat exchange and upstream of the low-temperature heat exchange; as well as The compression process upstream of the high-temperature heat exchange and downstream of the low-temperature heat exchange.

18. The PTES of claim 17, further comprising a heat recovery unit that recovers heat from the working fluid during operation in the charging cycle and the power generation cycle.

19. The PTES of claim 17, wherein the high-temperature heat storage is a closed heat storage containing a heat medium selected from the group consisting of sand or gravel, concrete, encapsulated phase change material, bulk phase change material, or combinations thereof.

20. The PTES of claim 10, further comprising a heat recovery unit that recovers heat from the working fluid during operation in the charging cycle and the power generation cycle.

21. A pumped thermal energy storage system ("PTES") as shown and described.

22. A method for use in a pumped thermal energy storage system ("PTES") as shown and described.

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