Heat pump type energy storage system and heat pump type energy storage method

Abstract

The invention provides a heat pump type energy storage system and a heat pump type energy storage method. The heat pump type energy storage system comprises a first working medium library and a second working medium library, a second working medium library; the energy storage module comprises an energy storage flow path, a heat storage loop and a heat storage device, and the energy storage flow path enables the energy storage working medium output by the first working medium library to convert electric energy into pressure energy of the energy storage working medium after being compressed by a positive Brayton cycle, cooled by heat exchange with a first heat exchanger and cooled and liquefied by a first cooler in the energy storage flow path; the heat storage loop and the heat storage device enable electric energy to be converted into heat energy of a first heat storage medium, and energy storage is achieved. And the energy release module comprises an energy release flow path, the energy release flow path and the heat storage device enable pressure energy of the energy storage working medium and heat energy of the first heat storage medium to be converted into electric energy together, energy release is achieved, the energy storage efficiency of the system is fundamentally improved, the electricity storage quantity and the electricity generation quantity are improved, and the electricity peak clipping and valley filling effect is improved.

Description

Technical Field

[0001] The present application relates to the field of energy storage technology, and in particular to a heat pump type energy storage system and a heat pump type energy storage method. Background Art

[0002] Heat pump energy storage is a new type of long-term, large-scale energy storage technology route with broad development prospects. Heat pump energy storage is mainly based on the Brayton thermodynamic cycle and heat storage technology. It has similar technical principles and system components to compressed working fluid energy storage (such as compressed air energy storage and compressed carbon dioxide energy storage). Since heat pump energy storage converts electrical energy into thermal energy for storage, heat pump energy storage has more advantages than compressed working fluid energy storage in terms of energy density, site selection flexibility, and construction cost. However, the energy storage circuit of the heat pump energy storage system is a reverse Brayton cycle heat pump circuit, and the energy release circuit is a positive Brayton cycle heat engine circuit. Both circuits have large irreversible losses. After the losses are superimposed, the energy storage efficiency of the entire system is low, at around 50%, which is not conducive to the commercial application of the technology. Summary of the invention

[0003] In view of this, the present application provides a heat pump type energy storage system, which improves energy storage efficiency. In addition, the present application also provides a heat pump type energy storage method applicable to the above heat pump type energy storage system.

[0004] In order to achieve the above objectives, this application provides the following technical solutions:

[0005] A heat pump type energy storage system, comprising:

[0006] The first working fluid reservoir is used to store energy storage working fluid in a gas-liquid-solid mixed state;

[0007] A second working fluid reservoir, used for storing the energy storage working fluid in liquid state;

[0008] The energy storage module comprises an energy storage flow path, a heat storage circuit and a heat storage device, wherein the energy storage flow path comprises a first compressor, a heat path of a first heat exchanger and a first cooler connected in series in sequence, wherein the inlet of the first compressor is connected to the outlet of the first working fluid reservoir, and the outlet of the first cooler is connected to the inlet of the second working fluid reservoir, so that the energy storage working fluid output from the first working fluid reservoir is compressed in the energy storage flow path by a positive Brayton cycle, cooled by heat exchange with the first heat exchanger, and cooled and liquefied by the first cooler, and then the electrical energy is converted into the pressure energy of the energy storage working fluid; the heat storage circuit comprises The cold circuit of the first heat exchanger, the second compressor, the hot circuit of the second heat exchanger, the first expander and the cold circuit of the first heat exchanger are sequentially connected in series, a circulating working medium flows in the heat storage circuit, a first heat storage medium is stored in the heat storage device, and the heat storage device is connected to the cold circuit of the second heat exchanger, so that the circulating working medium is sequentially expanded by a reverse Brayton cycle, heated by heat exchange with the first heat exchanger, compressed by a reverse Brayton cycle, and cooled by heat exchange with the second heat exchanger in the heat storage circuit, so that electrical energy is converted into thermal energy of the first heat storage medium, thereby realizing energy storage;

[0009] The energy release module includes an energy release flow path, which includes a cold path of a third heat exchanger, a cold path of a fourth heat exchanger, a second expander, a hot path of the third heat exchanger and a second cooler connected in series in sequence, the inlet of the cold path of the third heat exchanger is connected to the outlet of the second working fluid reservoir, the outlet of the second cooler is connected to the inlet of the first working fluid reservoir, and the heat storage device is connected to the hot path of the fourth heat exchanger, so that the energy storage working fluid is vaporized, heated by heat exchange with the fourth heat exchanger, and expanded by a positive Brayton cycle, so that the pressure energy of the energy storage working fluid and the thermal energy of the first heat storage medium are converted into electrical energy together to achieve energy release.

[0010] Optionally, the above-mentioned heat pump type energy storage system further includes a waste heat recovery module, which is used to absorb heat from the energy storage flow path and release heat to the energy release flow path.

[0011] Optionally, in the above-mentioned heat pump type energy storage system, the waste heat recovery module includes a first heat exchange device, a first cold tank, a first hot tank, and a second heat exchange device, the first cold tank and the first hot tank both store a second heat storage medium, the heat path of the first heat exchange device is connected between the heat path of the first heat exchanger and the first cooler, and the second heat exchange device is connected between the outlet of the second working fluid reservoir and the cold path of the third heat exchanger;

[0012] Among them, in the energy storage stage of the waste heat recovery module, the second heat storage medium flows out from the first cold tank and absorbs the heat of the energy storage working fluid in the energy storage flow path through the first heat exchange device and enters the first hot tank. In the energy release stage, the second heat storage medium flows out from the first hot tank and releases heat to the energy storage working fluid in the energy release flow path through the second heat exchange device and returns to the first cold tank.

[0013] Optionally, in the above heat pump type energy storage system, the first heat exchange device includes a plurality of fifth heat exchangers connected in series;

[0014] The second heat exchange device includes a plurality of sixth heat exchangers connected in series and arranged in one-to-one correspondence with the fifth heat exchangers.

[0015] Optionally, in the above-mentioned heat pump type energy storage system, a plurality of first heat tanks are provided, and a first heat tank is provided between each sixth heat exchanger and its corresponding fifth heat exchanger, so that the second heat storage medium absorbs the heat of the energy storage medium in stages.

[0016] Optionally, in the above-mentioned heat pump type energy storage system, the energy release flow path also includes a cooling device connected between the second cooler and the first working fluid reservoir.

[0017] Optionally, in the above-mentioned heat pump type energy storage system, the cooling device is a third expander, so as to expand the energy storage medium and cool the energy storage medium at the same time.

[0018] Optionally, in the above heat pump type energy storage system, the heat storage device includes a second cold tank and a second hot tank;

[0019] Among them, in the energy storage stage of the heat storage device, the first heat storage medium flows out of the second cold tank and enters the second hot tank after heat exchange and temperature increase with the second heat exchanger; in the energy release stage, the first heat storage medium flows out of the second hot tank and enters the second cold tank after heat exchange and temperature decrease with the fourth heat exchanger.

[0020] Optionally, in the above heat pump type energy storage system, the energy storage medium is carbon dioxide; and / or,

[0021] The circulating working medium is air, nitrogen, argon or helium; and / or,

[0022] The first heat storage medium is molten salt or heat transfer oil; and / or,

[0023] The second heat storage medium is water.

[0024] A heat pump type energy storage method, which uses any of the heat pump type energy storage systems described above, and the heat pump type energy storage method includes: when the electricity is valley, controlling the energy storage module to operate; when the electricity is peak, controlling the energy release module to operate.

[0025] The present application provides a heat pump type energy storage system, wherein the energy storage module includes an energy storage flow path, a heat storage circuit and a heat storage device, wherein the energy storage medium in the energy storage flow path is compressed, cooled and liquefied by a positive Brayton cycle, so that the electric energy is converted into the pressure energy of the energy storage medium; the heat storage circuit is connected to the energy storage flow path through a first heat exchanger, and the heat storage circuit is connected to the heat storage device through a second heat exchanger, so that the circulating medium flowing through the heat storage circuit absorbs the compression heat of the energy storage medium through the first heat exchanger after the expansion process of the reverse Brayton cycle, and releases the heat to the first heat storage medium of the heat storage device through the second heat exchanger after the compression process of the reverse Brayton cycle, so that the electric energy is converted into the thermal energy of the first heat storage medium; the energy release module includes an energy release flow path, and the energy release flow path is connected to the heat storage device through a fourth heat exchanger, so that the energy storage medium is vaporized, and absorbs the heat of the first heat storage medium through the fourth heat exchanger and undergoes the expansion process of the positive Brayton cycle, so that the pressure energy of the energy storage medium and the thermal energy of the first heat storage medium are converted into electric energy together. It can be seen that the energy storage module in the present application includes the compression process and expansion process of the reverse Brayton cycle, and the compression process of the positive Brayton cycle, and the energy release module includes the expansion process of the positive Brayton cycle. Compared with the prior art, the energy storage module includes the compression process and expansion process of the reverse Brayton cycle, and the energy release module includes the expansion process and compression process of the positive Brayton cycle. It can be seen that the energy release process of the present application has no power consumption link, only the power generation link, which fundamentally improves the energy storage efficiency of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0027] Figure 1 A schematic diagram of a heat pump type energy storage system provided in an embodiment of the present application.

[0028] exist Figure 1 middle:

[0029] 1. First working fluid reservoir; 2. Second working fluid reservoir; 3. Energy storage module; 4. Energy release module; 5. Waste heat recovery module;

[0030] 31. Energy storage flow path; 32. Heat storage circuit; 33. Heat storage device;

[0031] 311. a first compressor; 312. a first cooler;

[0032] 321, a first heat exchanger; 322, a second compressor; 323, a second heat exchanger; 324, a first expander;

[0033] 331, second cold tank; 332, second hot tank;

[0034] 41. Energy release flow path;

[0035] 411, third heat exchanger; 412, fourth heat exchanger; 413, second expander; 414, second cooler; 415, cooling device;

[0036] 51. Fifth heat exchanger; 52. First cold tank; 53. First hot tank; 54. Sixth heat exchanger. DETAILED DESCRIPTION

[0037] The present application provides a heat pump type energy storage system, which improves energy storage efficiency. In addition, the present application also provides a heat pump type energy storage method applicable to the above heat pump type energy storage system.

[0038] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0039] like Figure 1 As shown, an embodiment of the present application provides a heat pump type energy storage system, including: a first working fluid reservoir 1, a second working fluid reservoir 2, an energy storage module 3 and an energy release module 4, wherein the first working fluid reservoir 1 is used to store energy storage working fluid in a gas-liquid-solid mixed state, the second working fluid reservoir 2 is used to store liquid energy storage working fluid, the energy storage module 3 includes an energy storage flow path 31, a heat storage circuit 32 and a heat storage device 33, the heat storage circuit 32 is connected to the energy storage flow path 31 and the heat storage device 33 respectively, and the energy release module 4 includes an energy release flow path 41.

[0040] More specifically, the energy storage circuit 31 includes a first compressor 311, a first heat exchanger 321 and a first cooler 312 connected in series in sequence. The inlet of the first compressor 311 is connected to the outlet of the first working fluid reservoir 1, and the outlet of the first cooler 312 is connected to the inlet of the second working fluid reservoir 2, so that the energy storage working fluid output from the first working fluid reservoir 1 is compressed in the energy storage circuit 31 by the positive Brayton cycle, cooled by heat exchange with the first heat exchanger 321, and cooled and liquefied by the first cooler 312, and the electrical energy is converted into the pressure energy of the energy storage working fluid; the heat storage circuit 32 includes a first heat exchanger 321 connected in series in sequence. The heat storage device 33 includes a cold circuit, a second compressor 322, a hot circuit of the second heat exchanger 323, a first expander 324 and a cold circuit of the first heat exchanger 321. A circulating working fluid flows in the heat storage circuit 32. The first heat storage medium is stored in the heat storage device 33. The heat storage device 33 is connected to the heat storage circuit 32 through the cold circuit of the second heat exchanger 323, so that the circulating working fluid is sequentially expanded by the reverse Brayton cycle, heated by heat exchange with the first heat exchanger 321, compressed by the reverse Brayton cycle, and cooled by heat exchange with the second heat exchanger 323 in the heat storage circuit 32, so that the electrical energy is converted into the thermal energy of the first heat storage medium, thereby realizing energy storage.

[0041] The energy release flow path 41 includes a cold circuit of a third heat exchanger 411, a cold circuit of a fourth heat exchanger 412, a second expander 413, a hot circuit of the third heat exchanger 411 and a second cooler 414 which are connected in series in sequence. The inlet of the cold circuit of the third heat exchanger 411 is connected to the inlet of the second working fluid reservoir 2, the outlet of the second cooler 414 is connected to the inlet of the first working fluid reservoir 1, and the heat storage device 33 is connected to the hot circuit of the fourth heat exchanger 412, so that the energy storage working fluid is vaporized, heated by heat exchange with the fourth heat exchanger 412, and expanded by a positive Brayton cycle, so that the pressure energy of the energy storage working fluid and the thermal energy of the first heat storage medium are converted into electrical energy together to realize energy release.

[0042] It can be seen that the energy storage module 3 in the present application includes the compression process and expansion process of the reverse Brayton cycle, and the compression process of the positive Brayton cycle, and the energy release module 4 includes the expansion process of the positive Brayton cycle. Compared with the prior art, the energy storage module 3 includes the compression process and expansion process of the reverse Brayton cycle, and the energy release module 4 includes the expansion process and compression process of the positive Brayton cycle. It can be seen that the energy release process of the present application has no power consumption link, only the power generation link, which fundamentally improves the energy storage efficiency of the system, and under the condition that the installed power of the compressor and the expander is the same, the system's energy storage capacity during energy storage and the power generation during energy release are greatly improved, which is beneficial to power peak shaving.

[0043] In the heat pump type energy storage system of the present application, the positive Brayton cycle composed of the compression process and the expansion process of the energy storage working fluid is divided into independent compression process (assuming that the compression work consumption is Wc1) and expansion process (assuming that the expansion work is Wt1), which are performed in the energy storage and energy release stages respectively, so that the system includes the reverse Brayton cycle of the circulating working fluid (assuming that the compression work consumption is Wc2 and the expansion work is Wt2) and the compression process of the energy storage working fluid in the energy storage stage; according to the original heat pump type energy storage method, the energy storage efficiency η1=(Wt1-Wc1) / (Wc2-Wt2), but according to the method of the present invention, the energy storage efficiency η2=Wt1 / (Wc2-Wt2+Wc1), then:

[0044] η1-η2=[Wc1·(Wt1+Wt2-Wc1-Wc2)] / [(Wc2-Wt2)(Wc2-Wt2+Wc1)], because from the perspective of the entire system, Wt1+Wt2 is the total output work, and Wc1+Wc2 is the total input work. Because there will be losses, (Wt1+Wt2-Wc1-Wc2)<0, so η1<η2, that is, the present application can improve the energy storage efficiency of heat pump type energy storage. At the same time, it can be seen that the system's storage capacity increases by Wc1 during energy storage, and the power generation increases by Wc1 during energy release, thereby achieving a better effect of power peak shaving and valley filling.

[0045] Furthermore, it also includes a waste heat recovery module 5, which is used to absorb the heat of the energy storage flow path 31 and release the heat to the energy release flow path 41 to achieve full utilization of energy, avoid energy waste, and improve energy storage efficiency.

[0046] Furthermore, the waste heat recovery module 5 includes a first heat exchange device, a first cold tank 52, a first hot tank 53 and a second heat exchange device. The first cold tank 52 and the first hot tank 53 both store a second heat storage medium. The heat path of the first heat exchange device is connected between the heat path of the first heat exchanger 321 and the first cooler 312, and the second heat exchange device is connected between the second working fluid reservoir 2 and the cold path of the third heat exchanger 411; wherein, in the energy storage stage of the waste heat recovery module 5, the second heat storage medium flows out of the first cold tank 52 and absorbs the heat of the energy storage working fluid in the energy storage path 31 through the first heat exchange device and enters the first hot tank 53; in the energy release stage, the second heat storage medium flows out of the first hot tank 53 and releases heat to the energy storage working fluid in the energy release path 41 through the second heat exchange device and returns to the first cold tank 52. It can be seen that the composition of the waste heat recovery module 5 is simple, the heat recovery method is simple and reliable, and an efficient and low-cost heat recovery method is achieved.

[0047] Furthermore, the first heat exchange device includes a plurality of fifth heat exchangers 51 connected in series; the second heat exchange device includes a plurality of sixth heat exchangers 54 connected in series, and is arranged one-to-one with the fifth heat exchangers 51. By connecting a plurality of heat exchangers in series, cascade utilization of heat can be achieved, that is, the high-temperature fluid is gradually cooled down through a plurality of heat exchangers, while the low-temperature fluid is gradually heated up, thereby improving thermal efficiency and improving energy utilization efficiency.

[0048] There are multiple first heat tanks 53, and a first heat tank 53 is arranged between each sixth heat exchanger 54 and its corresponding fifth heat exchanger 51, so that the second heat storage medium absorbs the heat of the energy storage medium in stages.

[0049] In a certain example of the present application, the waste heat recovery module 5 includes a first cold tank 52, three first hot tanks 53, three fifth heat exchangers 51, and three sixth heat exchangers 54. A first hot tank 53 is arranged between each fifth heat exchanger 51 and each sixth heat exchanger 54. For the convenience of explanation, the three fifth heat exchangers 51 and the three sixth heat exchangers 54 are named according to the flow direction of the second heat storage medium. The heat exchanger that the second heat storage medium first enters is named the upstream heat exchanger, and the heat exchanger that the second heat storage medium enters last is the downstream heat exchanger. The heat exchanger located between the upstream heat exchanger and the downstream heat exchanger is the midstream heat exchanger. Then, the three fifth heat exchangers 51 are named the upstream fifth heat exchanger, the midstream fifth heat exchanger, and the downstream fifth heat exchanger, and the three sixth heat exchangers 54 are named the upstream sixth heat exchanger, the midstream sixth heat exchanger, and the downstream sixth heat exchanger. The sixth heat exchanger, wherein the upstream fifth heat exchanger is connected to the downstream sixth heat exchanger, the midstream fifth heat exchanger is connected to the midstream sixth heat exchanger, and the downstream fifth heat exchanger is connected to the upstream sixth heat exchanger. At the same time, the first heat tank 53 connected between the upstream fifth heat exchanger and the downstream sixth heat exchanger is named the upstream first heat tank, the first heat tank 53 connected between the midstream fifth heat exchanger and the midstream sixth heat exchanger is named the midstream first heat tank, and the first heat tank 53 connected between the downstream fifth heat exchanger and the upstream sixth heat exchanger is named the midstream first heat tank.

[0050] In the energy storage stage, the second heat storage medium is output from the first cold tank 52, and after absorbing heat through the upstream fifth heat exchanger, it is divided into two paths, one path is input to the upstream first hot tank, and the other path is divided into two paths after absorbing heat through the midstream fifth heat exchanger, one path is input to the midstream first hot tank, and the other path is input to the downstream first hot tank after absorbing heat through the downstream fifth heat exchanger; in the energy release stage, the second heat storage medium is output from the downstream first hot tank, and after releasing heat through the upstream sixth heat exchanger, it is merged with the second heat storage medium output from the midstream first hot tank and input to the midstream sixth heat exchanger after releasing heat, and then merged with the second heat storage medium output from the upstream first hot tank and input to the first cold tank 52, thereby realizing the step-by-step recovery and utilization of heat, avoiding heat loss, and improving the thermal efficiency of the system.

[0051] In some optional embodiments, the energy release flow path 41 also includes a cooling device 415 connected between the second cooler 414 and the first working fluid reservoir 1. After being cooled by the second cooler 414, the energy storage working fluid enters the cooling device 415 again for cooling. It can be seen that two cooling mechanisms are selected on the energy release flow path 41. This method makes the layout of the cooling device 415 and the second cooler 414 more flexible, and the selection of the cooling device 415 and the second cooler 414 is more flexible.

[0052] Furthermore, the cooling device 415 is a third expander, which can expand the energy storage medium while cooling the energy storage medium, thereby further improving the power generation efficiency.

[0053] In some optional embodiments, the heat storage device 33 includes a second cold tank 331 and a second hot tank 332; wherein, in the energy storage stage of the heat storage device 33, the first heat storage medium flows out of the second cold tank 331 and enters the second hot tank 332 after heat exchange and temperature increase with the second heat exchanger 323; in the energy release stage, the first heat storage medium flows out of the second hot tank 332 and enters the second cold tank 331 after heat exchange and temperature decrease with the fourth heat exchanger 412. This heat recovery method is simple, reliable and highly efficient.

[0054] In some optional embodiments, the energy storage working fluid is carbon dioxide, which makes the cost of the energy storage working fluid low, and realizes the resource utilization and long-term storage of carbon dioxide, with excellent comprehensive benefits; and / or, the circulating working fluid is air, nitrogen, argon or helium; and / or, the first heat storage medium is molten salt or heat transfer oil; and / or, the second heat storage medium is water, which is normal pressure water, so that the heat storage cost is low.

[0055] In addition, the present application also provides a heat pump type energy storage method, including: when the electricity is off-peak, controlling the energy storage module 3 to operate; when the electricity is peak, controlling the energy release module 4 to operate.

[0056] Energy storage stage: The gaseous energy storage medium output from the first working fluid reservoir 1 is pressurized and heated by the first compressor 311 to a pressure of about 8 MPa, and then the heat is transferred to the circulating working fluid through the first heat exchanger 321. The circulating working fluid is pressurized and heated by the second compressor 322 to a temperature of more than 500°C, and then the heat is transferred to the first heat storage medium through the second heat exchanger 323 for storage. The temperature of the energy storage medium output from the first heat exchanger 321 is about 100°C, and then the heat is transferred to the second heat storage medium in sections and stored through multiple fifth heat exchangers 51 connected in series, and then the heat is input into the first cooler 312 for cooling, and finally input into the second working fluid reservoir 2 for storage;

[0057] Energy release stage: the second working fluid reservoir 2 outputs the energy storage working fluid, which is sequentially preheated through multiple sixth heat exchangers 54 connected in series, heated through the third heat exchanger 411 and the fourth heat exchanger 412, input into the second expander 413 to expand and do work, then passes through the third heat exchanger 411 and multiple sixth heat exchangers 54 connected in series to release the residual heat in stages, then passes through the second cooler 414 to cool, then passes through the third expander to expand and do work, and finally enters the first working fluid reservoir 1 for storage.

[0058] The basic principles of the present application are described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, effects, etc. mentioned in the present application are only examples and not limitations, and it cannot be considered that these advantages, strengths, effects, etc. are required by each embodiment of the present application. In addition, the specific details disclosed above are only for the purpose of illustration and ease of understanding, not for limitation, and the above details do not limit the present application to being implemented by adopting the above specific details.

[0059] The block diagrams of the devices, apparatuses, equipment, and systems involved in this application are only illustrative examples and are not intended to require or imply that they must be connected, arranged, and configured in the manner shown in the block diagram. As will be appreciated by those skilled in the art, these devices, apparatuses, equipment, and systems can be connected, arranged, and configured in any manner. Words such as "including", "comprising", "having", etc. are open words, referring to "including but not limited to", and can be used interchangeably with them. The words "or" and "and" used here refer to the words "and / or" and can be used interchangeably with them, unless the context clearly indicates otherwise. The words "such as" used here refer to the phrase "such as but not limited to", and can be used interchangeably with them.

[0060] It should also be noted that in the device and apparatus of the present application, each component or each step can be decomposed and / or reassembled. Such decomposition and / or reassembly should be regarded as an equivalent solution of the present application.

[0061] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects without departing from the scope of the present application. Therefore, the present application is not intended to be limited to the aspects shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

[0062] It should be understood that the qualifiers "first", "second", "third", "fourth", "fifth" and "sixth" used in the description of the embodiments of the present application are only used to more clearly explain the technical solutions and cannot be used to limit the scope of protection of the present application.

[0063] The above description has been given for the purpose of illustration and description. In addition, this description is not intended to limit the embodiments of the present application to the forms disclosed herein. Although multiple example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions and sub-combinations thereof.

Claims

1. A heat pump type energy storage system, characterized in that: include: A first working fluid reservoir (1) is used to store energy storage working fluid in a gas-liquid-solid mixed state; A second working fluid reservoir (2) for storing the energy storage working fluid in liquid form; An energy storage module (3) comprises an energy storage flow path (31), a heat storage circuit (32) and a heat storage device (33); the energy storage flow path (31) comprises a first compressor (311), a heat path of a first heat exchanger (321) and a first cooler (312) which are sequentially connected in series; the inlet of the first compressor (311) is connected to the outlet of the first working fluid reservoir (1); the outlet of the first cooler (312) is connected to the inlet of the second working fluid reservoir (2), so that the energy storage working fluid output from the first working fluid reservoir (1) is compressed in the energy storage flow path (31) by a positive Brayton cycle, cooled by heat exchange with the first heat exchanger, and liquefied by cooling by the first cooler (312), thereby converting electrical energy into pressure energy of the energy storage working fluid; the heat storage circuit (32) comprises a first compressor (311), a first heat exchanger (321) and a first cooler (312); (32) comprises a cold circuit of the first heat exchanger (321), a second compressor (322), a hot circuit of the second heat exchanger (323), a first expander (324) and a cold circuit of the first heat exchanger (321) which are sequentially connected in series, a circulating working fluid flows in the heat storage circuit, a first heat storage medium is stored in the heat storage device (33), and the heat storage device (33) is connected to the cold circuit of the second heat exchanger (323), so that the circulating working fluid is sequentially expanded in the heat storage circuit (32) by a reverse Brayton cycle, heated by heat exchange with the first heat exchanger (321), compressed by a reverse Brayton cycle, and cooled by heat exchange with the second heat exchanger (323) in the heat storage circuit (32), so that the electrical energy is converted into the thermal energy of the first heat storage medium, thereby realizing energy storage; The energy release module (4) comprises an energy release flow path (41), wherein the energy release flow path (41) comprises a cold path of a third heat exchanger (411), a cold path of a fourth heat exchanger (412), a second expander (413), a hot path of the third heat exchanger (411) and a second cooler (414) which are connected in series in sequence, wherein the inlet of the cold path of the third heat exchanger (411) is connected to the outlet of the second working fluid reservoir (2), the outlet of the second cooler (414) is connected to the inlet of the first working fluid reservoir (1), and the heat storage device (33) is connected to the hot path of the fourth heat exchanger (412), so that the energy storage working fluid is vaporized, heated by heat exchange with the fourth heat exchanger (412), and expanded by a positive Brayton cycle, so that the pressure energy of the energy storage working fluid and the thermal energy of the first heat storage medium are converted into electrical energy together, thereby realizing energy release.

2. The heat pump type energy storage system according to claim 1, characterized in that: It also comprises a waste heat recovery module (5), wherein the waste heat recovery module (5) is used to absorb heat from the energy storage flow path (31) and release heat to the energy release flow path (41).

3. The heat pump type energy storage system according to claim 2, characterized in that: The waste heat recovery module (5) comprises a first heat exchange device, a first cold tank (52), a first hot tank and a second heat exchange device, wherein the first cold tank (52) and the first hot tank (53) both store a second heat storage medium, the heat circuit of the first heat exchange device is connected between the heat circuit of the first heat exchanger (321) and the first cooler (312), and the second heat exchange device is connected between the outlet of the second working fluid reservoir (2) and the cold circuit of the third heat exchanger (411); In the energy storage stage of the waste heat recovery module (5), the second heat storage medium flows out from the first cold tank (52) and absorbs the heat of the energy storage medium in the energy storage flow path (31) through the first heat exchange device and enters the first hot tank (53); in the energy release stage, the second heat storage medium flows out from the first hot tank (53) and releases the heat to the energy storage medium in the energy release flow path (41) through the second heat exchange device and returns to the first cold tank (52).

4. The heat pump type energy storage system according to claim 3, characterized in that: The first heat exchange device comprises a plurality of fifth heat exchangers (51) connected in series; The second heat exchange device comprises a plurality of sixth heat exchangers (54) connected in series and arranged in one-to-one correspondence with the fifth heat exchangers (51).

5. The heat pump type energy storage system according to claim 4, characterized in that: The first heat tank (53) is provided in plurality, and a first heat tank 5 (3) is provided between each sixth heat exchanger (54) and its corresponding fifth heat exchanger (51), so that the second heat storage medium absorbs the heat of the energy storage medium in stages.

6. The heat pump type energy storage system according to claim 1, characterized in that: The energy release flow path (41) further comprises a temperature reduction device (415) connected between the second cooler (414) and the first working fluid reservoir (1).

7. The heat pump type energy storage system according to claim 6, characterized in that: The cooling device (415) is a third expander, which can cool the energy storage medium while expanding the energy storage medium.

8. The heat pump type energy storage system according to claim 1, characterized in that: The heat storage device (33) comprises a second cold tank (331) and a second hot tank (332); In the energy storage stage of the heat storage device (33), the first heat storage medium flows out of the second cold tank (331) and enters the second hot tank (332) after heat exchange with the second heat exchanger (323) to increase the temperature; in the energy release stage, the first heat storage medium flows out of the second hot tank (332) and enters the second cold tank (331) after heat exchange with the fourth heat exchanger (412) to decrease the temperature.

9. The heat pump type energy storage system according to claim 3, characterized in that: The energy storage medium is carbon dioxide; and / or, The circulating working medium is air, nitrogen, argon or helium; and / or, The first heat storage medium is molten salt or heat transfer oil; and / or, The second heat storage medium is water.

10. A heat pump type energy storage method, characterized in that: The application is a heat pump type energy storage system as claimed in any one of claims 1 to 9, wherein the heat pump type energy storage method comprises: When the power is off-peak, controlling the energy storage module (3) to operate; When the electricity is at peak, the energy release module (4) is controlled to operate.

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