CN116317177A

CN116317177A - Carbon dioxide energy storage system capable of adapting to wide energy storage pressure range and control method thereof

Info

Publication number: CN116317177A
Application number: CN202310247850.0A
Authority: CN
Inventors: 谢永慧; 汪晓勇; 王鼎; 孙磊; 郭永亮; 张荻; 杨彪; 陈强; 王林
Original assignee: Baihe New Energy Technology Shenzhen Co ltd
Current assignee: Baihe New Energy Technology Shenzhen Co ltd
Priority date: 2023-03-07
Filing date: 2023-03-07
Publication date: 2023-06-23

Abstract

The invention provides a carbon dioxide energy storage system capable of adapting to a wide energy storage pressure range and a control method thereof, and belongs to the technical field of energy storage. The carbon dioxide energy storage system suitable for the wide energy storage pressure range comprises an air storage, an energy storage component, a carbon dioxide condenser, an energy storage container, an energy release component, a control module and a variable temperature cold source component, wherein the air storage, the energy storage component, the carbon dioxide condenser, the energy storage container and the energy release component are sequentially connected in a closed loop mode. The control module is used for controlling the variable temperature cold source assembly to output a cooling medium with corresponding working parameters according to the state parameters of the gas-phase carbon dioxide output by the energy storage assembly; the carbon dioxide condenser is used for enabling gaseous carbon dioxide flowing through the carbon dioxide condenser to be condensed into a liquid phase under the cooling of a cooling medium provided by the variable temperature cold source component. The carbon dioxide energy storage system adaptable to the wide energy storage pressure range can adapt to different energy storage pressures.

Description

Carbon dioxide energy storage system capable of adapting to wide energy storage pressure range and control method thereof

Technical Field

The invention relates to the technical field of energy storage, in particular to a carbon dioxide energy storage system adaptable to a wide energy storage pressure range and a control method thereof.

Background

The carbon dioxide gas-liquid phase-change energy storage technology has the advantages of simple structure, flexible arrangement, higher energy storage efficiency and the like. The gas-liquid phase-change carbon dioxide energy storage system utilizes redundant electric power to compress gaseous carbon dioxide at normal temperature and normal pressure in the energy storage process, then condenses the gaseous carbon dioxide into medium-pressure liquid carbon dioxide which is stored in a storage tank, and most of the liquid carbon dioxide is condensed by adopting warm water. When external power is insufficient or the running load of the compressor is actually required to be reduced (such as matching peak shaving), at the moment, the carbon dioxide pressure is reduced due to insufficient output of the compressor, or the working state of the compressor deviates from the design working condition in the starting process of the compressor, and when the carbon dioxide pressure at the outlet of the compressor does not reach the energy storage pressure, the situation that normal-temperature water cannot condense medium-pressure gaseous carbon dioxide, the system efficiency is reduced and even normal running cannot be realized can occur.

It should be noted that the information of the present invention in the above background section is only for enhancing the understanding of the background of the present invention and thus may include information that does not form the prior art that is already known to those of ordinary skill in the art.

Disclosure of Invention

The invention aims to overcome at least one defect of the prior art, and provides a carbon dioxide energy storage system capable of adapting to a wide energy storage pressure range and a control method thereof, so that the range of the energy storage pressure adapted to the carbon dioxide energy storage system is widened, different energy storage pressure requirements can be met, the application range of the system is further improved, and the energy storage efficiency and the energy utilization rate of the system are improved.

According to a first aspect of the invention, there is provided a carbon dioxide energy storage system adaptable to a wide energy storage pressure range, comprising a gas storage, an energy storage assembly, a carbon dioxide condenser, an energy storage container and an energy release assembly connected in a closed loop in sequence, and comprising a control module and a variable temperature cold source assembly; the outlet of the gas storage is connected with the inlet of the energy storage component, the outlet of the energy storage component is connected with the inlet of the carbon dioxide channel of the carbon dioxide condenser, and the outlet of the carbon dioxide channel of the carbon dioxide condenser is connected with the inlet of the energy storage container; the outlet of the energy storage container is connected with the inlet of the energy release assembly, and the outlet of the energy release assembly is connected with the inlet of the gas storage;

the control module is used for controlling the variable temperature cold source assembly to output a cooling medium with corresponding working parameters according to the state parameters of the gas-phase carbon dioxide output by the energy storage assembly; the carbon dioxide condenser is used for enabling gaseous carbon dioxide flowing through the carbon dioxide condenser to be condensed into a liquid phase under the cooling of a cooling medium provided by the variable temperature cold source component.

According to one embodiment of the present invention, the state parameter of the gaseous carbon dioxide output by the energy storage component includes an energy storage pressure of the gaseous carbon dioxide;

The control module is used for controlling the variable temperature cold source assembly to output a cooling medium with corresponding temperature to the carbon dioxide condenser according to the energy storage pressure of the gas-phase carbon dioxide output by the energy storage assembly.

According to one embodiment of the invention, the state parameters of the gas-phase carbon dioxide output by the energy storage component further comprise the flow rate and the temperature of the gas-phase carbon dioxide;

the control module is used for controlling the variable temperature cold source assembly to output a cooling medium with corresponding flow to the carbon dioxide condenser according to the flow and the temperature of the gas-phase carbon dioxide output by the energy storage assembly.

According to one embodiment of the invention, the energy storage assembly comprises one or more energy storage heat exchange units connected in series or in parallel, each energy storage heat exchange unit comprises a carbon dioxide compressor and a carbon dioxide heat exchanger, and an outlet of the carbon dioxide compressor is connected with a carbon dioxide inlet of the carbon dioxide heat exchanger; the carbon dioxide compressor in the energy storage heat exchange unit at the initial end is connected with the gas storage, the carbon dioxide heat exchanger in the energy storage heat exchange unit at the tail end is connected with the carbon dioxide condenser, and the energy storage pressure of the gas-phase carbon dioxide output by the energy storage component is the pressure of the carbon dioxide at the tail end at the carbon dioxide compressor outlet of the energy storage heat exchange unit, the carbon dioxide outlet of the carbon dioxide heat exchanger or the inlet of the carbon dioxide channel of the carbon dioxide condenser.

According to one embodiment of the invention, the variable temperature heat sink assembly comprises a heat supplying portion and a cooling portion;

the cooling part is used for providing a cooling medium for the carbon dioxide condenser;

the refrigeration part is used for controlling the temperature of the cooling medium provided to the carbon dioxide condenser under the control of the control module.

According to one embodiment of the present invention, the refrigeration part includes a refrigerant compressor, a refrigerant condenser, a refrigerant expansion valve, and a refrigerant evaporator; an outlet of the refrigerant compressor is connected with an inlet of a refrigerant channel of the refrigerant condenser, an outlet of the refrigerant channel of the refrigerant condenser is connected with an inlet of the refrigerant expansion valve, an outlet of the refrigerant expansion valve is connected with an inlet of a refrigerant channel of the refrigerant evaporator, and an outlet of the refrigerant channel of the refrigerant evaporator is connected with an inlet of the refrigerant compressor;

the cooling part comprises a first pipeline and a second pipeline; the inlet of the first pipeline is connected with the outlet of the cooling medium channel of the refrigerant evaporator, the outlet of the first pipeline is connected with the inlet of the cooling medium channel of the carbon dioxide condenser, the inlet of the second pipeline is connected with the outlet of the cooling medium channel of the carbon dioxide condenser, and the outlet of the second pipeline is connected with the inlet of the cooling medium channel of the refrigerant evaporator.

According to one embodiment of the invention, the control module is configured to: and controlling the opening degree of the refrigerant expansion valve according to the energy storage pressure of the gas-phase carbon dioxide output by the energy storage component.

According to one embodiment of the invention, the refrigeration section further comprises a flow control valve located between the refrigerant expansion valve and the refrigerant evaporator;

the control module is configured to control the opening degree of the flow control valve according to the flow rate of the gas-phase carbon dioxide output by the energy storage component.

According to one embodiment of the invention, the variable temperature heat sink assembly comprises a refrigerant compressor, a refrigerant condenser and a refrigerant expansion valve;

the inlet of the refrigerant compressor is connected with the outlet of the cooling medium channel of the carbon dioxide condenser, the outlet of the refrigerant compressor is connected with the inlet of the refrigerant channel of the refrigerant condenser, the outlet of the refrigerant channel of the refrigerant condenser is connected with the inlet of the refrigerant expansion valve, and the outlet of the refrigerant expansion valve is connected with the inlet of the cooling medium channel of the carbon dioxide condenser;

the control module is configured to control the opening degree of the refrigerant expansion valve according to the pressure of the gas-phase carbon dioxide output by the energy storage assembly.

According to a second aspect of the present invention, there is provided a control method of a carbon dioxide energy storage system adaptable to a wide range of storage pressures, comprising:

in an energy storage stage, the energy storage component and the carbon dioxide condenser work to compress and condense the gas-phase carbon dioxide in the gas storage into liquid-phase carbon dioxide, and store the liquid-phase carbon dioxide in the energy storage container; the control module controls the variable temperature cold source assembly to output a cooling medium with corresponding working parameters according to the state parameters of the gas-phase carbon dioxide in the energy storage assembly so as to ensure that the gas-phase carbon dioxide flowing through the carbon dioxide condenser is condensed to a liquid phase.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention as claimed.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and together with the description, serve to explain the principles of the invention. It is evident that the drawings in the following description are only some embodiments of the present invention and that other drawings may be obtained from these drawings without inventive effort for a person of ordinary skill in the art.

FIG. 1 is a schematic diagram of a carbon dioxide energy storage system adaptable to a wide range of storage pressures in accordance with an embodiment of the present invention.

Fig. 2 is a schematic diagram illustrating interaction between an energy storage component and a control module according to an embodiment of the present invention.

Fig. 3 is a schematic diagram illustrating interaction between an energy storage component and a control module according to an embodiment of the present invention.

FIG. 4 is a schematic diagram of a carbon dioxide energy storage system adaptable to a wide range of storage pressures in accordance with an embodiment of the present invention.

FIG. 5 is a schematic diagram of a carbon dioxide energy storage system adaptable to a wide range of storage pressures in accordance with an embodiment of the present invention.

FIG. 6 is a schematic diagram of a carbon dioxide energy storage system adaptable to a wide range of storage pressures in accordance with an embodiment of the present invention.

FIG. 7 is a schematic diagram of a carbon dioxide energy storage system adaptable to a wide range of storage pressures in accordance with an embodiment of the present invention.

FIG. 8 is a schematic diagram of a carbon dioxide energy storage system adaptable to a wide range of storage pressures in accordance with an embodiment of the present invention.

FIG. 9 is a schematic diagram of a carbon dioxide energy storage system adaptable to a wide range of storage pressures in accordance with an embodiment of the present invention.

FIG. 10 is a schematic diagram of a carbon dioxide energy storage system adaptable to a wide range of storage pressures in accordance with an embodiment of the present invention.

Detailed Description

Example embodiments will now be described more fully with reference to the accompanying drawings. However, the exemplary embodiments can be embodied in many forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the example embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and thus detailed descriptions thereof will be omitted. Furthermore, the drawings are merely schematic illustrations of the present invention and are not necessarily drawn to scale.

The terms "a," "an," "the," "said" and "at least one" are used to indicate the presence of one or more elements/components/etc.; the terms "comprising" and "having" are intended to be inclusive and mean that there may be additional elements/components/etc. in addition to the listed elements/components/etc.; the terms "first," "second," and "third," etc. are used merely as labels, and do not limit the number of their objects.

The embodiment of the invention provides a carbon dioxide energy storage system capable of adapting to a wide energy storage pressure range, referring to fig. 1, the carbon dioxide energy storage system capable of adapting to the wide energy storage pressure range comprises a gas storage 1, an energy storage assembly 100, a carbon dioxide condenser 7, an energy storage container 8 and an energy release assembly 200 which are sequentially connected in a closed loop, and comprises a control module 18 and a variable temperature cold source assembly 300; the outlet of the gas storage 1 is connected with the inlet of the energy storage assembly 100, the outlet of the energy storage assembly 100 is connected with the inlet of the carbon dioxide channel of the carbon dioxide condenser 7, and the outlet of the carbon dioxide channel of the carbon dioxide condenser 7 is connected with the inlet of the energy storage container 8; the outlet of the energy storage container 8 is connected with the inlet of the energy release assembly, and the outlet of the energy release assembly is connected with the inlet of the gas storage 1; wherein, the control module 18 is configured to control the variable temperature cold source assembly 300 to output a cooling medium corresponding to the working parameter according to the state parameter of the gas-phase carbon dioxide output by the energy storage assembly 100; the carbon dioxide condenser 7 is configured to condense the gaseous carbon dioxide flowing through the carbon dioxide condenser 7 into a liquid phase under the cooling of the cooling medium provided by the variable temperature heat sink assembly 300.

In the energy release phase, the energy release assembly 200 operates to expand the carbon dioxide from the energy storage container 8 to generate electricity and store the expanded gas phase carbon dioxide in the gas storage 1. During the energy storage phase, the energy storage assembly 100 may be operated to compress the gaseous carbon dioxide in the gas reservoir 1; the compressed gaseous carbon dioxide may be condensed into liquid carbon dioxide by a carbon dioxide condenser 7 and flowed into an energy storage vessel 8 for storage. Therefore, the carbon dioxide energy storage system which can adapt to the wide energy storage pressure range can release energy to generate power in the electricity utilization peak time, and can utilize surplus electric power to store energy in the electricity utilization valley time so as to achieve the effects of peak regulation and valley filling.

In the related art, normally, normal temperature water is used to condense the gaseous carbon dioxide flowing through the carbon dioxide condenser 7. However, if the compressor in the energy storage assembly 100 is not powered enough, such as low valley power or the power of the compressor in the energy storage assembly 100 needs to be reduced in conjunction with peak shaving, or the working state of the compressor deviates from the design working condition during the start-up of the compressor, the pressure of the gaseous carbon dioxide flowing into the carbon dioxide channel of the carbon dioxide condenser 7 will be reduced, which will result in the condensation temperature of the gaseous carbon dioxide being reduced, so that the gaseous carbon dioxide is at risk of not being fully condensed. In other words, in the prior art, the carbon dioxide energy storage system is designed according to the determined energy storage pressure, the range of the applicable energy storage pressure is narrower, and when the pressure of the gas-phase carbon dioxide is insufficient due to the fact that the power of the energy storage component 100 is insufficient or the working state of the compressor deviates from the design working condition, etc., the pressure of the gas-phase carbon dioxide is easily reduced to be out of the range of the applicable energy storage pressure of the carbon dioxide energy storage system, so that the system efficiency of the carbon dioxide energy storage system is reduced and even cannot normally run.

In an embodiment of the present invention, a carbon dioxide energy storage system adaptable to a wide range of storage pressures includes a control module 18 and a variable temperature heat sink assembly 300. Unlike the related art, the control module 18 can control the working state of the variable temperature cold source assembly 300 according to the state parameter of the gas-phase carbon dioxide in the energy storage assembly 100, so as to avoid the problem that the carbon dioxide flowing into the carbon dioxide condenser 7 cannot be sufficiently condensed and liquefied due to insufficient cooling capacity or insufficient cooling medium temperature provided by the variable temperature cold source assembly 300. In other words, the carbon dioxide energy storage system capable of adapting to the wide energy storage pressure range according to the embodiment of the invention can control the variable temperature cold source assembly 300 through the control module 18, and the variable temperature cold source assembly 300 outputs a cooling medium adapted to the condensation temperature requirement of the carbon dioxide condenser 7, so that the low energy storage pressure gas phase carbon dioxide of the carbon dioxide energy storage system capable of adapting to the wide energy storage pressure range can be condensed into a liquid phase for storage in the energy storage container 8. Therefore, the energy storage pressure range adapted to the carbon dioxide energy storage system adaptable to the wide energy storage pressure range is greatly expanded, the characteristic of adapting to the wide energy storage pressure range is provided, the carbon dioxide energy storage system adaptable to the wide energy storage pressure range can further maintain higher energy storage efficiency, normal operation is guaranteed, and the flexibility of the carbon dioxide energy storage system adaptable to the wide energy storage pressure range is improved.

Specifically, the carbon dioxide energy storage system capable of adapting to the wide energy storage pressure range provided by the embodiment of the invention can be controlled by adopting the following control method to enlarge the energy storage pressure range adapted to the carbon dioxide energy storage system capable of adapting to the wide energy storage pressure range:

in the energy storage phase, the energy storage assembly 100 and the carbon dioxide condenser 7 operate to compress and condense the gaseous carbon dioxide in the gas storage 1 into liquid carbon dioxide and store in the energy storage container 8; the control module 18 controls the working state of the variable temperature cold source assembly 300 according to the state parameter of the gaseous carbon dioxide output by the energy storage assembly 100, and further controls the variable temperature cold source assembly to output a cooling medium with a corresponding working parameter, so as to ensure that the gaseous carbon dioxide flowing through the carbon dioxide condenser 7 is condensed to a liquid phase.

In one embodiment of the present invention, referring to FIG. 1, the carbon dioxide energy storage system adaptable to a wide range of storage pressures further includes a carbon dioxide evaporator 9 positioned between the energy storage vessel 8 and the energy release assembly 200; the carbon dioxide inlet of the carbon dioxide evaporator 9 is connected with the outlet of the energy storage container 8, and the carbon dioxide outlet of the carbon dioxide evaporator 9 is connected with the inlet of the energy release assembly 200. In the energy release stage, the liquid-phase carbon dioxide in the energy storage container 8 can flow into a carbon dioxide channel of the carbon dioxide evaporator 9, and the liquid-phase carbon dioxide is heated in the carbon dioxide evaporator 9 to be evaporated to form gas-phase carbon dioxide; the energy release assembly 200 operates to expand the gaseous carbon dioxide to generate electricity and store the expanded gaseous carbon dioxide in the gas storage 1.

The structure, principles and effects of a carbon dioxide energy storage system adaptable to a wide energy storage pressure range according to embodiments of the present invention are further explained and illustrated below with reference to the accompanying drawings.

In one embodiment of the present invention, the energy storage assembly 100 further includes a detector, configured to acquire a status parameter of the gaseous carbon dioxide output by the energy storage assembly 100 and send the status parameter to the control module 18, so that the control module 18 controls the working state of the variable temperature cold source assembly 300 according to the acquired status parameter of the gaseous carbon dioxide. Alternatively, the number of the detectors may be one or more, and the kinds of the detectors may be one or more, so as to meet the state parameters of the gas-phase carbon dioxide required for obtaining. For example, when the status parameter comprises the flow rate of gaseous carbon dioxide, the detector may comprise a flow meter; when the status parameter comprises the temperature of the gaseous carbon dioxide, the detector may comprise a thermometer; when the state parameter comprises the stored energy pressure of the gaseous carbon dioxide, the detector may comprise a pressure gauge.

In one embodiment of the invention, the state parameter of the gaseous carbon dioxide output by the energy storage assembly comprises the energy storage pressure of the gaseous carbon dioxide; the control module 18 is configured to control the variable temperature cold source assembly 300 to output a cooling medium with a corresponding temperature to the carbon dioxide condenser 7 according to the energy storage pressure of the gas-phase carbon dioxide output by the energy storage assembly. In other words, variable temperature cold source assembly 300 is a variable temperature cold source under the control of control module 18; when the compressor output of the energy storage assembly 100 is insufficient or the energy storage pressure of the gaseous carbon dioxide is changed due to other reasons, the variable temperature heat sink assembly 300 can provide cooling mediums with different temperatures for the carbon dioxide condenser 7 under the control of the control module 18, so as to ensure that the gaseous carbon dioxide is condensed in the carbon dioxide condenser 7. The control module 18 may control the refrigeration state of the variable temperature cold source assembly 300 according to the energy storage pressure of the carbon dioxide to control the temperature of the cooling medium provided to the carbon dioxide condenser 7 by the variable temperature cold source assembly 300, so as to ensure that the gas-phase carbon dioxide in the carbon dioxide condenser 7 can be cooled to or below the condensation temperature. This may enable the temperature of the cooling medium provided by variable temperature heat sink assembly 300 to be matched to the condensation temperature of the gaseous carbon dioxide, thereby ensuring that the gaseous carbon dioxide in carbon dioxide condenser 7 can be condensed. Alternatively, the control module 18 may determine the condensation temperature of the carbon dioxide based on the stored energy pressure of the carbon dioxide.

In one example, the control module 18 may cause the temperature of the cooling medium provided to the carbon dioxide condenser 7 to be lower than the determined condensation temperature of carbon dioxide by controlling the cooling state of the variable temperature heat sink assembly 300, for example, causing the temperature of the cooling medium provided to the carbon dioxide condenser 7 to be 3-10 ° lower than the determined condensation temperature of carbon dioxide.

In one embodiment of the invention, the status parameters of the gaseous carbon dioxide include the flow rate of the carbon dioxide and the storage pressure of the carbon dioxide. The control module 18 is configured to control the variable temperature cold source assembly 300 to output a cooling medium with a corresponding temperature and flow rate to the carbon dioxide condenser 7 according to the flow rate and the energy storage pressure of the gas-phase carbon dioxide output by the energy storage assembly. For example, the control module 18 controls the flow and temperature conditions of the variable temperature heat sink assembly 300 such that the cooling medium provides cooling to meet the cooling required for condensation of gaseous carbon dioxide. This can make the flow rate of the cooling medium provided by the variable temperature cold source assembly 300 match the flow rate of the gaseous carbon dioxide, avoid insufficient liquefaction of the gaseous carbon dioxide caused by insufficient flow rate of the cooling medium provided by the variable temperature cold source assembly 300, and avoid waste caused by excessive flow rate of the cooling medium provided by the variable temperature cold source assembly 300.

Further, the state parameters of the gaseous carbon dioxide comprise the flow rate of the carbon dioxide, the energy storage pressure of the carbon dioxide and the temperature of the carbon dioxide; the control module 18 is configured to control the variable temperature heat sink assembly to output a cooling medium with a corresponding flow rate to the carbon dioxide condenser according to the flow rate and the temperature of the gas-phase carbon dioxide output by the energy storage assembly 100. For example, the control module 18 may determine the condensation temperature of the gaseous carbon dioxide based on the stored energy pressure of the gaseous carbon dioxide, and may determine the exotherm of the gaseous carbon dioxide in the carbon dioxide condenser 7 during condensation based on the temperature and condensation temperature of the gaseous carbon dioxide output by the energy storage assembly, and the flow rate of the carbon dioxide. Based on the determined amount of heat release from the gaseous carbon dioxide, control module 18 may control at least one of the cooling state and/or the flow state of variable temperature heat sink assembly 300, for example, both the cooling state and the flow state, such that the heat absorption power of the cooling medium provided by variable temperature heat sink assembly 300 to carbon dioxide condenser 7 can meet the heat release power requirements of the gaseous carbon dioxide.

In some embodiments of the invention, the energy storage assembly 100 comprises one or more energy storage heat exchange units 110 connected in series or in parallel, each comprising a carbon dioxide compressor 101 (e.g. carbon dioxide first compressor 3 in fig. 5, or e.g. carbon dioxide first compressor 3, carbon dioxide first compressor 5 in fig. 6, 8, 10) and a carbon dioxide heat exchanger 102 (e.g. carbon dioxide first heat exchanger 4 in fig. 5, or e.g. carbon dioxide first heat exchanger 4, carbon dioxide second heat exchanger 6 in fig. 6, 8, 10), the outlet of the carbon dioxide compressor 101 being connected to the carbon dioxide inlet of the carbon dioxide heat exchanger 102; the carbon dioxide compressor 101 in the initial energy storage heat exchange unit 110 is connected with the gas storage 1, the carbon dioxide heat exchanger 102 in the final energy storage heat exchange unit 110 is connected with the carbon dioxide condenser 7, and the energy storage pressure of the gas phase carbon dioxide output by the energy storage component is the pressure of the carbon dioxide at the outlet of the carbon dioxide compressor of the final energy storage heat exchange unit, the pressure of the carbon dioxide at the carbon dioxide outlet of the carbon dioxide heat exchanger, or the pressure of the carbon dioxide at the inlet of the carbon dioxide channel of the carbon dioxide condenser.

In one embodiment of the present invention, referring to fig. 2 and 3, the energy storage assembly 100 includes a plurality of energy storage heat exchange units 110 sequentially cascaded (in series), and any one of the energy storage heat exchange units 110 includes a carbon dioxide compressor 101 and a carbon dioxide heat exchanger 102; the carbon dioxide heat exchanger 102 has a carbon dioxide passage. In the same energy-storage heat exchange unit 110, the outlet of the carbon dioxide compressor 101 is connected with the carbon dioxide inlet of the carbon dioxide heat exchanger 102. Between two adjacent energy storage heat exchange units 110, the outlet of the carbon dioxide channel of the carbon dioxide heat exchanger 102 of the upper stage is connected with the inlet of the carbon dioxide compressor 101 of the lower stage; an inlet of the carbon dioxide compressor 101 of the first-stage energy-storage heat exchange unit 110 is connected with an outlet of the gas storage 1, and an outlet of a carbon dioxide channel of the carbon dioxide heat exchanger 102 of the last-stage energy-storage heat exchange unit 110 is connected with an inlet of a carbon dioxide channel of the carbon dioxide condenser 7. In this way, the carbon dioxide pressure at the outlet of each carbon dioxide compressor 101 increases stepwise. In one example, the energy storage pressure of the carbon dioxide is the pressure of the carbon dioxide at the outlet of the carbon dioxide compressor 101 (e.g. shown in fig. 3) of the energy storage heat exchange unit 110 of the last stage, or the pressure of the carbon dioxide at the outlet of the carbon dioxide channel of the carbon dioxide heat exchanger 102 (e.g. shown in fig. 2), or the pressure of the carbon dioxide at the inlet of the carbon dioxide channel of the carbon dioxide condenser 7 (e.g. shown in fig. 2, 3). In this way, the pressure of the carbon dioxide at the outlet of the carbon dioxide compressor 101 or the outlet of the carbon dioxide heat exchanger 102 of the energy storage heat exchange unit 110 of the last stage is substantially the same as the pressure of the carbon dioxide in the gas phase at the inlet of the carbon dioxide passage of the carbon dioxide condenser 7.

In the examples of fig. 2 and 3, an example is illustrated in which the energy storage assembly 100 includes two-stage and three-stage energy storage heat exchange units 110 in series. It will be appreciated that the energy storage assembly 100 includes more than four stages of energy storage heat exchange units 110 as desired.

For example, in the carbon dioxide energy storage system capable of adapting to a wide energy storage pressure range shown in fig. 6, the energy storage assembly 100 includes two-stage energy storage heat exchange units 110 connected in series, that is, a carbon dioxide first compressor 3, a carbon dioxide first heat exchanger 4, a carbon dioxide second compressor 5, and a carbon dioxide second heat exchanger 6 connected in series in order. The inlet of the carbon dioxide first compressor 3 is connected with the outlet of the gas storage 1, the outlet of the carbon dioxide first compressor 3 is connected with the inlet of the carbon dioxide channel of the carbon dioxide first heat exchanger 4, the outlet of the carbon dioxide channel of the carbon dioxide first heat exchanger 4 is connected with the inlet of the carbon dioxide second compressor 5, the outlet of the carbon dioxide second compressor 5 is connected with the inlet of the carbon dioxide channel of the carbon dioxide second heat exchanger 6, and the outlet of the carbon dioxide channel of the carbon dioxide second heat exchanger 6 is connected with the inlet of the carbon dioxide channel of the carbon dioxide condenser 7.

In another embodiment of the present invention, the energy storage assembly 100 may comprise only one energy storage heat exchange unit 110, i.e. one carbon dioxide compressor 101 and one carbon dioxide heat exchanger 102. For example, in the carbon dioxide energy storage system shown in fig. 5, which can accommodate a wide range of storage pressures, the storage heat exchange unit comprises a carbon dioxide first compressor 3 and a carbon dioxide first heat exchanger 4. An inlet of the carbon dioxide first compressor 3 is connected with an outlet of the gas storage 1, an outlet of the carbon dioxide first compressor 3 is connected with an inlet of a carbon dioxide channel of the carbon dioxide first heat exchanger 4, and an outlet of the carbon dioxide channel of the carbon dioxide first heat exchanger 4 is connected with an inlet of a carbon dioxide channel of the carbon dioxide condenser 7. In the example of fig. 5, the control module 18 may obtain a status parameter of the gaseous carbon dioxide at the outlet of the carbon dioxide first compressor 3. It will be appreciated that in further examples, the control module 18 may also obtain a status parameter of the gaseous carbon dioxide at the outlet of the carbon dioxide channel of the carbon dioxide first heat exchanger 4.

In one embodiment of the present invention, referring to fig. 4, the variable temperature heat sink assembly 300 includes a cooling portion 310 and a refrigerating portion 320. The cooling part is used for providing a cooling medium for the carbon dioxide condenser 7; the refrigeration part is used for controlling the temperature of the cooling medium supplied to the carbon dioxide condenser 7 under the control of the control module 18. In this embodiment, the refrigerating section is used for refrigerating to cool down the cooling medium, and the cooled down cooling medium may be introduced into the cooling medium passage of the carbon dioxide condenser 7 for cooling down the gas phase carbon dioxide in the carbon dioxide passage of the carbon dioxide condenser 7. For example, as shown in fig. 4, the cooling portion may provide a cooling medium (labeled LB1 in fig. 4) having a first temperature to the cooling portion, and the cooling portion may control the temperature of the cooling medium flowing through the cooling portion under the control of the control module 18 to flow out the cooling medium (labeled LB2 in fig. 4) having a second temperature; the cooling section causes the cooling medium having the second temperature to flow into the cooling medium passage of the carbon dioxide condenser 7 for heat exchange, and the cooling medium (denoted by LB3 in fig. 4) having the third temperature flows out of the carbon dioxide condenser 7. The second temperature is lower than the first temperature when the refrigerating part 320 operates to cool down the cooling medium flowing therethrough. Of course, if the refrigeration section is not operating, the second temperature is substantially equal to the first temperature.

In some examples, when the temperature of the cooling medium (first temperature) is able to meet the temperature required for the carbon dioxide condenser 7 to condense the gaseous carbon dioxide, the refrigeration part may be inactive under the control of the control module 18, i.e. the second temperature is equal to the first temperature; the cooling section causes a cooling medium to flow into the carbon dioxide passage of the carbon dioxide condenser 7 for cooling down the carbon dioxide in the gas phase under the control of the control module 18. When the temperature of the cooling medium (first temperature) cannot meet the temperature required for the carbon dioxide condenser 7 to condense the carbon dioxide in the gas phase, the refrigerating part may be operated under the control of the control module 18 so as to lower the temperature of the cooling medium to a temperature required for the carbon dioxide condenser 7 to condense the carbon dioxide in the gas phase (i.e., second temperature). Therefore, the refrigerating part and the cooling part do not need to work synchronously, but work according to the working condition requirement, so that the running time of the refrigerating part can be reduced, the overall power consumption of the refrigerating part can be reduced, the power consumption of a carbon dioxide energy storage system applicable to a wide energy storage pressure range can be further reduced, and the energy storage efficiency can be improved.

Further, referring to fig. 5, the cooling portion may be provided with a reservoir 24, such as a water tank. When the cooling section is operated, the cooling medium in the reservoir 24 may be caused to flow into the cooling medium passage of the carbon dioxide condenser 7. The cooling medium in the cooling section may flow through the cooling section before flowing from the cooling section to the carbon dioxide condenser 7. The refrigeration section is not operated when the temperature of the cooling medium in the cooling section can meet the demand. When the temperature of the cooling medium in the cooling portion is not satisfactory, the cooling portion may be operated such that the cooling medium flowing through the cooling portion is cooled to a satisfactory temperature.

Further, the cooling medium flowing through the carbon dioxide condenser 7 may be returned to the reservoir 24, so that the cooling medium is recycled. Alternatively, the cooling medium in the liquid storage 24 may be used as a heat source of other parts in the carbon dioxide energy storage system that can adapt to a wide energy storage pressure range, for example, as a heat source of the carbon dioxide evaporator 9, so as to achieve heat recovery and reduce the temperature thereof, which illustrates that the carbon dioxide evaporator 9 has a carbon dioxide channel and a heat source channel, one end of the liquid storage 24 is connected to an inlet of the heat source channel of the carbon dioxide evaporator 9, and the other end of the liquid storage 24 is connected to an outlet of the heat source channel of the carbon dioxide evaporator 9. During the energy storage, the cooling medium which has been warmed up and passed through the carbon dioxide condenser 7 is stored in the reservoir 24. Upon release of energy, the cooling medium stored in the reservoir 24 enters the heat source channel of the carbon dioxide evaporator 9 to heat the carbon dioxide flowing through the carbon dioxide channel of the carbon dioxide evaporator 9.

In one example, the cooling medium may be water.

In one example, the control module 18 may also receive the temperature of the cooling medium flowing into the cooling portion to determine whether to activate the cooling portion based on the temperature of the cooling medium. In other words, the cooling portion has a temperature detector for detecting the temperature of the cooling medium (first temperature) before flowing into the cooling portion and feeding back temperature information to the control module 18. The control module 18 may determine whether to activate the cooling portion to cool the cooling medium flowing through the cooling portion based on temperature information (first temperature) fed back by the cooling portion.

In one example, the cooling section is further provided with a driving pump, and the control module 18 may also control the flow rate of the driving pump, i.e. the flow rate of the cooling medium, in accordance with the amount of heat released from the carbon dioxide in the gas phase in the carbon dioxide condenser 7. Therefore, the flow of the cooling medium, the flow of the driving pump and the flow of the gaseous carbon dioxide are matched, and the situation that the flow of the driving pump is too large or too small is avoided, so that the power of the driving pump is accurately controlled is realized. This can avoid unnecessary power consumption due to too large a flow rate of the drive pump, and can avoid insufficient liquefaction of the carbon dioxide in the gas phase in the carbon dioxide condenser 7 due to too small a flow rate of the drive pump. It will be appreciated that the lower the storage pressure of the gaseous carbon dioxide, the lower the required condensing temperature; correspondingly, the lower the temperature of the cooling medium is required. The larger the flow rate of the gas-phase carbon dioxide, the larger the amount of heat released by the gas-phase carbon dioxide during condensation, and the larger the flow rate of the cooling medium.

In one example, variable temperature heat sink assembly 300 is capable of providing carbon dioxide condenser 7 with a cooling medium of 0-20℃ (e.g., cold water of 0-20℃) capable of meeting the energy storage pressure requirement of 4MPa to 7MPa. Thus, the energy storage pressure range adapted to the carbon dioxide energy storage system adaptable to the wide energy storage pressure range can be 4MPa to 7MPa.

In one embodiment of the present invention, referring to fig. 5, the cooling part includes a first pipe and a second pipe; the inlet of the first pipeline and the outlet of the second pipeline are connected with the refrigerating part, the outlet of the first pipeline is connected with the inlet of the cooling medium channel of the carbon dioxide condenser 7, and the inlet of the second pipeline is connected with the outlet of the cooling medium channel of the carbon dioxide condenser 7. Alternatively, the reservoir may be provided on the second conduit. In this way, the cooling medium flowing out of the carbon dioxide condenser 7 can flow into the liquid reservoir 24 for cooling; the cooling medium flowing out of the reservoir 24 may flow through the refrigerating section and then into the carbon dioxide condenser 7.

Alternatively, the reservoir may comprise a first reservoir and a second reservoir in series; the inlet of the first liquid reservoir is connected with the outlet of the cooling medium channel of the carbon dioxide condenser 7, the outlet of the first liquid reservoir is connected with the inlet of the second liquid reservoir, and the outlet of the second liquid reservoir is connected with the refrigerating part. A control valve is arranged between the first liquid reservoir and the second liquid reservoir. In one example, during the energy storage phase, the cooling medium in the second reservoir is at a lower temperature (first temperature), which can flow through the refrigeration section before flowing into the carbon dioxide condenser 7 for cooling the gaseous carbon dioxide. The temperature of the cooling medium flowing out of the carbon dioxide condenser 7 (third temperature) is high, which may be stored in the first reservoir. Therefore, the cooling medium flowing into the refrigeration part can be kept at a lower temperature, and further the starting of the refrigeration part is avoided or the power consumption of the refrigeration part during the starting is reduced. Further, the cooling medium stored in the first reservoir has a relatively high temperature, and may be used as a heat source (e.g., as a heat source of the carbon dioxide evaporator 9) to cool, and the cooled cooling medium may flow into the first reservoir to serve as a cold source of the carbon dioxide condenser 7.

It is understood that when the cooling portion is provided with the driving pump, the driving pump may be provided in the first pipe or in the second pipe. In one example, the drive pump is disposed between the second reservoir and the refrigeration portion, or the drive pump is disposed in the first conduit.

In one embodiment of the present invention, referring to fig. 5, the refrigerating part includes a refrigerant compressor 20, a refrigerant condenser 21, a refrigerant expansion valve 22, and a refrigerant evaporator 23. The refrigerant condenser 21 has a refrigerant passage, and the refrigerant evaporator 23 has a refrigerant passage and a cooling medium passage. The outlet of the refrigerant compressor 20 is connected to the inlet of the refrigerant passage of the refrigerant condenser 21, the outlet of the refrigerant passage of the refrigerant condenser 21 is connected to the inlet of the refrigerant expansion valve 22, the outlet of the refrigerant expansion valve 22 is connected to the inlet of the refrigerant passage of the refrigerant evaporator 23, and the outlet of the refrigerant passage of the refrigerant evaporator 23 is connected to the inlet of the refrigerant compressor 20. The cooling part comprises a first pipeline and a second pipeline; the inlet of the first pipeline is connected with the outlet of the cooling medium channel of the refrigerant evaporator 23, the outlet of the first pipeline is connected with the inlet of the cooling medium channel of the carbon dioxide condenser 7, the inlet of the second pipeline is connected with the outlet of the cooling medium channel of the carbon dioxide condenser 7, and the outlet of the second pipeline is connected with the inlet of the cooling medium channel of the refrigerant evaporator 23.

When the refrigerating part works, the liquid-phase refrigerant passes through the refrigerant expansion valve 22, expands and reduces pressure and then enters the refrigerant channel of the refrigerant evaporator 23; the liquid-phase refrigerant exchanges heat with the cooling medium flowing through the cooling medium channel of the refrigerant evaporator 23 in the refrigerant channel of the refrigerant evaporator 23 to raise the temperature, so that the temperature of the cooling medium is lowered; in this process, the liquid phase refrigerant may absorb heat to evaporate into a gas phase refrigerant. The gas-phase refrigerant can be compressed and pressurized by the refrigerant compressor 20, and then enters a refrigerant channel of the refrigerant condenser 21 to exchange heat and cool, and is condensed into liquid-phase refrigerant. In this way, the cooling portion may be operated to cool the cooling medium flowing through the refrigerant passage of the refrigerant evaporator 23. When the refrigerating section operates under the control of the control module 18, the operation state of any one or more of the refrigerant compressor 20, the refrigerant condenser 21, the refrigerant expansion valve 22 and the refrigerant evaporator 23 thereof may be controlled by the control module 18, thereby achieving control of the refrigerating temperature and the refrigerating speed (refrigerating power).

In one example, the control module 18 is configured to: the opening degree of the refrigerant expansion valve 22 is controlled according to the pressure of the carbon dioxide. In this way, by controlling the opening degree of the refrigerant expansion valve 22, the pressure of the refrigerant in the refrigerant evaporator 23 can be controlled, and further, the evaporation pressure of the refrigerant can be controlled, thereby realizing the control of the evaporation temperature of the refrigerant in the refrigerant evaporator 23. By controlling the evaporation temperature in the refrigerant, control of the temperature of the cooling medium flowing through the refrigerant evaporator 23 can be achieved so that the temperature of the cooling medium flowing out of the refrigerant evaporator 23 can meet the temperature required for condensing the gaseous carbon dioxide in the carbon dioxide condenser 7. It will be appreciated that when the pressure of the refrigerant output from the refrigerant compressor 20 is constant, the adjustment of the refrigerant evaporating pressure can be achieved by adjusting the opening degree of the refrigerant expansion valve 22.

In one example, referring to fig. 6, the refrigeration section further includes a flow valve flow control valve 31 located between the refrigerant expansion valve 22 and the refrigerant evaporator 23. The control module 18 is configured to control the opening degree of the flow control valve 31 according to the flow rate of the carbon dioxide. In this way, by controlling the opening of the flow rate control valve 31, the flow rate of the refrigerant flowing into the refrigerant evaporator 23, and thus the cooling rate (cooling power) of the cooling portion, can be controlled so that the cooling rate of the cooling portion matches the flow rate of carbon dioxide. This can avoid the risk that the gas-phase carbon dioxide in the carbon dioxide condenser 7 cannot be sufficiently liquefied due to insufficient cooling speed of the cooling part, and can also avoid the waste caused by excessive cooling capacity due to excessively high cooling speed (excessively high cooling power) of the cooling part.

In one example, the refrigerant may be an organic refrigerant, and in particular may be selected from the group consisting of R22, R410a, R404a, and the like, to meet refrigeration and environmental requirements.

In one example, the refrigerant condenser 21 may be an air-cooled condenser that may cool down a gas-phase refrigerant located in the refrigerant passage with air such that the gas-phase refrigerant is condensed into a liquid-phase refrigerant.

In another example, the refrigerant condenser 21 may be a water-cooled condenser that may cool the gas-phase refrigerant in the refrigerant passage with water (e.g., normal temperature water or cold water) so that the gas-phase refrigerant is condensed into a liquid-phase refrigerant.

In still other embodiments, referring to fig. 7 and 8, the variable temperature heat sink assembly 300 may include a refrigerant compressor 20, a refrigerant condenser 21, and a refrigerant expansion valve 22. Wherein the refrigerant condenser 21 has a cooling medium passage. An inlet of the refrigerant compressor 20 is connected to an outlet of the cooling medium passage of the carbon dioxide condenser 7, an outlet of the refrigerant compressor 20 is connected to an inlet of the refrigerant passage of the refrigerant condenser 21, an outlet of the refrigerant passage of the refrigerant condenser 21 is connected to an inlet of the refrigerant expansion valve 22, and an outlet of the refrigerant expansion valve 22 is connected to an inlet of the cooling medium passage of the carbon dioxide condenser 7. The control module 18 is configured to control the opening of the refrigerant expansion valve 22 in accordance with the pressure of the carbon dioxide. In this embodiment, the liquid-phase cooling medium may be depressurized by post-expansion of the refrigerant expansion valve 22, and enter the cooling medium passage of the carbon dioxide condenser 7 as a low-temperature cooling medium to exchange heat with the gas-phase carbon dioxide in the carbon dioxide passage of the carbon dioxide condenser 7. In the heat exchange process in the carbon dioxide condenser 7, the gas-phase carbon dioxide in the carbon dioxide channel is cooled down and condensed into liquid-phase carbon dioxide; the low-temperature cooling medium in the cooling medium passage absorbs heat to evaporate into a gas-phase cooling medium and serves as a temperature-increasing cooling medium. The temperature-increasing cooling medium is compressed and pressurized by the refrigerant compressor 20, and the compressed and pressurized refrigerant compressor 20 is cooled to a liquid-phase cooling medium by a cooling medium passage of the refrigerant condenser 21.

The liquid-phase cooling medium is expanded and depressurized by the refrigerant expansion valve 22 and then enters the cooling medium channel of the carbon dioxide condenser 7, and the opening degree of the refrigerant expansion valve 22 determines the pressure in the cooling medium channel of the carbon dioxide condenser 7, and the pressure is the evaporation pressure of the cooling medium in the cooling medium channel. The evaporation pressure of the cooling medium determines the evaporation temperature at which the cooling medium evaporates into the gas phase, which evaporation temperature needs to be lower than the condensation temperature of the gas phase carbon dioxide in the carbon dioxide channels of the carbon dioxide condenser 7 in order to be able to condense the gas phase carbon dioxide. In this embodiment, the control module 18 can control the evaporation temperature of the liquid-phase cooling medium when it exchanges heat with the vapor-phase carbon dioxide in the cooling medium passage by controlling the opening degree of the refrigerant expansion valve 22, thereby ensuring that the vapor-phase carbon dioxide can be completely condensed.

In one example, referring to fig. 8, the variable temperature heat sink assembly 300 further includes a flow control valve 31 positioned between the refrigerant expansion valve 22 and the carbon dioxide condenser 7. The control module 18 is further configured to control the opening of the flow control valve 31 in accordance with the flow rate of the carbon dioxide. Thus, by controlling the opening of the flow control valve 31, the flow rate of the liquid-phase cooling medium flowing into the cooling medium passage of the carbon dioxide condenser 7 can be controlled, and the cooling capacity of the cooling portion can be controlled so that the cooling capacity of the cooling portion matches the heat absorption capacity at the time of condensing the carbon dioxide in the gas phase.

In one embodiment of the present invention, referring to fig. 4, a first control valve 29 may be further provided between the energy storage assembly 100 and the air reservoir 1. Thus, by controlling the opening or closing of the first control valve 29, it is possible to control whether a passage between the gas storage 1 and the energy storage assembly 100 is formed. In one example, during the energy release phase, the first control valve 29 may be closed to enable the gas reservoir 1 to store gaseous carbon dioxide.

In one embodiment of the present invention, referring to fig. 6, a preheater 2 may be provided between the energy storage assembly 100 and the air reservoir 1. In the energy storage stage, when the gas-phase carbon dioxide with lower temperature and pressure in the gas storage 1 flows through the preheater 2 and then flows into the energy storage assembly 100; the gaseous carbon dioxide may be heated up as it flows through the preheater 2.

In one embodiment of the invention, a fourth control valve 32 is arranged between the outlet of the energy storage container 8 and the inlet of the carbon dioxide channel of the carbon dioxide evaporator 9. By controlling the opening or closing of the fourth control valve 32, it is possible to control whether the liquid-phase carbon dioxide in the energy storage container 8 can flow into the carbon dioxide evaporator 9.

In an embodiment of the present invention, the energy release assembly 200 includes at least one stage of energy release heat exchange unit; each energy-releasing heat exchange unit is connected in series between the carbon dioxide evaporator 9 and the gas storage 1 through a pipeline. The energy-releasing heat exchange unit includes a turbine (e.g., turbine 13 in fig. 5, or turbine 11, turbine 13 in fig. 6, 8, 10, for example) and an energy-releasing heat exchanger (e.g., energy-releasing heat exchanger 12 in fig. 5, or energy-releasing heat exchanger 10, energy-releasing heat exchanger 12 in fig. 6, 8, 10, for example). Wherein the turbine comprises a turbine and a generator driven by the turbine. The energy release heat exchanger is provided with a carbon dioxide channel. In the same energy release heat exchange unit, the inlet of the turbine is connected with the outlet of the carbon dioxide channel of the energy release heat exchanger. When the energy-releasing heat exchanger works, the gas-phase carbon dioxide can flow through the carbon dioxide channel of the energy-releasing heat exchanger to be heated, and the heated gas-phase carbon dioxide expands when flowing through the energy-releasing heat exchanger to drive the turbine to generate electricity.

In one embodiment of the present invention, referring to FIG. 5, the energy release assembly 200 comprises an energy release heat exchange unit, the energy release assembly 200 comprising a turbine 13 and an energy release heat exchanger 12; the inlet of the carbon dioxide channel of the energy release heat exchanger 12 is connected with the outlet of the carbon dioxide channel of the carbon dioxide evaporator 9, the inlet of the turbine 13 is connected with the outlet of the carbon dioxide channel of the energy release heat exchanger 12, and the outlet of the turbine 13 is connected with the inlet of the gas storage 1. In the energy release phase, the gas phase carbon dioxide flowing through the carbon dioxide channels of the energy release heat exchanger 12 can be heated by the heat exchange medium in the heat exchange medium channels of the energy release heat exchanger 12; the heated gas-phase carbon dioxide flows into the turbine 13 to expand so as to push the turbine 13 to rotate, and then the generator connected with the turbine 13 is driven to generate electricity.

In another embodiment of the present invention, referring to fig. 6, the energy release assembly 200 includes a plurality of energy release heat exchange units cascaded in sequence. Wherein, the energy release heat exchanger 10 of the first stage energy release heat exchange unit has an inlet of a carbon dioxide channel connected with an outlet of a carbon dioxide channel of the carbon dioxide evaporator 9; the outlet of the turbine 13 of the final stage energy-releasing heat exchange unit is connected with the inlet of the gas storage 1; in the adjacent two-stage energy release heat exchange units, the outlet of the turbine 11 of the upper-stage energy release heat exchange unit is connected with the inlet of the carbon dioxide channel of the energy release heat exchanger 12 of the lower-stage energy release heat exchange unit. In the example of fig. 6, the energy release assembly 200 includes two cascaded energy release heat exchange units. It is understood that in other examples of embodiments of the invention, the energy release assembly 200 may also include three or more stages of energy release heat exchange units.

In one embodiment of the present invention, referring to fig. 6, a carbon dioxide cooler 14 is further provided between the energy release assembly 200 and the gas storage 1, and the gaseous carbon dioxide flowing out of the energy release assembly 200 is further cooled to normal temperature and pressure when flowing through the carbon dioxide cooler 14, and then stored in the gas storage 1. In this way, the gas-phase carbon dioxide flowing out of the energy release assembly 200 can be stored in the gas storage 1 after being cooled, so as to be beneficial to the operation safety of the gas storage 1.

In some embodiments of the invention, the adaptable wide range of storage pressure carbon dioxide storage system further includes a heat exchange assembly. Referring to fig. 9 and 10, the heat exchange assembly includes a cold storage tank 15 and a heat storage tank 16; the heat exchange medium in the cold storage tank 15 can flow through the energy storage assembly 100 to cool the gas-phase carbon dioxide in the energy storage assembly 100, and flows into the heat storage tank 16 after absorbing heat and raising temperature in the energy storage assembly 100. The heat exchange medium in the heat storage tank 16 can flow through the energy release assembly 200 to heat the gaseous carbon dioxide in the energy release assembly 200 and flow into the cold storage tank 15 after releasing heat and cooling. In one example, referring to fig. 10, the carbon dioxide first heat exchanger 4, the carbon dioxide second heat exchanger 6 in the energy storage assembly 100 has heat exchange medium channels, and the heat exchange medium in the cold storage tank 15 flows into the heat exchange medium channels of the carbon dioxide first heat exchanger 4, the carbon dioxide second heat exchanger 6 to exchange heat with the gas phase carbon dioxide located in the carbon dioxide channels of the carbon dioxide first heat exchanger 4, the carbon dioxide second heat exchanger 6. The energy release heat exchanger 10 and the energy release heat exchanger 12 in the energy release assembly 200 are provided with heat exchange medium channels, and the heat exchange medium in the heat storage tank 16 flows into the heat exchange medium channels of the energy release heat exchanger 10 and the energy release heat exchanger 12 so as to exchange heat with gas-phase carbon dioxide in the carbon dioxide channels of the energy release heat exchanger 10 and the energy release heat exchanger 12.

In this way, during the energy storage phase, the heat exchange medium in the cold storage tank 15 may flow through the energy storage assembly 100, specifically through the heat exchange medium channels of the carbon dioxide first heat exchanger 4 and the carbon dioxide second heat exchanger 6 of the energy storage assembly 100; in this way, the gaseous carbon dioxide flowing through the carbon dioxide channels of the carbon dioxide first heat exchanger 4 and the carbon dioxide second heat exchanger 6 can be cooled down, and the heat exchange medium flowing through the heat exchange medium channels of the carbon dioxide first heat exchanger 4 and the carbon dioxide second heat exchanger 6 can be heated and stored in the heat storage tank 16. In this way, in the energy storage stage, the carbon dioxide energy storage system which can adapt to a wide energy storage pressure range can realize compression energy storage and heat recovery. In the energy release phase, the heat exchange medium in the heat storage tank 16 may flow through the energy release assembly 200, specifically, the heat exchange medium channels of the energy release heat exchanger 10 and the energy release heat exchanger 12 of the energy release assembly 200, so as to supply heat to the gas-phase carbon dioxide flowing through the carbon dioxide channels of the energy release heat exchanger 10 and the energy release heat exchanger 12, and the heat exchange medium flowing through the heat exchange medium channels of the energy release heat exchanger 10 and the energy release heat exchanger 12 may be cooled and then stored in the cold storage tank 15. In this way, in the energy release stage, the carbon dioxide energy storage system which can adapt to a wide energy storage pressure range can realize energy release power generation and cold energy recovery.

In one embodiment of the invention, see fig. 10, a second control valve 30 is arranged between the outlet of the cold storage tank 15 and the inlets of the heat exchange medium channels of the carbon dioxide first heat exchanger 4, the carbon dioxide second heat exchanger 6. In this way, whether the heat exchange medium of low temperature can be supplied to the carbon dioxide first heat exchanger 4 and the carbon dioxide second heat exchanger 6 by the cold storage tank 15 can be controlled by opening or closing the second control valve 30.

In one embodiment of the present invention, referring to fig. 10, a third control valve 33 is provided between the outlet of the heat storage tank 16 and the inlets of the heat exchange medium channels of the energy releasing

heat exchanger

10, 12. In this way, it is possible to control whether the heat storage tank 16 can supply high-temperature heat exchange medium to the energy

release heat exchanger

10, 12 by opening or closing the third control valve 33.

In one embodiment of the present invention, referring to fig. 10, a driving pump may be provided on a flow path of the heat exchange medium flowing from the cold storage tank 15 to the heat storage tank 16 (particularly, on a pipe of the flow path). In the energy storage phase, the drive pump may be operated so that the heat exchange medium in the cold storage tank 15 flows into the heat storage tank 16 via the heat exchange medium channels of the carbon dioxide first heat exchanger 4 and the carbon dioxide second heat exchanger 6.

In one embodiment of the present invention, referring to fig. 10, a driving pump may be provided on a flow path of the heat exchange medium flowing from the heat storage tank 16 to the cold storage tank 15 (particularly, on a pipe of the flow path). In the energy release phase, the driving pump can be made to work so that the heat exchange medium in the heat storage tank 16 flows into the cold storage tank 15 through the heat exchange medium channels of the energy release heat exchanger 10 and the energy release heat exchanger 12.

In one embodiment of the present invention, referring to fig. 10, a heat exchange medium cooler 17 may be disposed between the outlets of the heat exchange medium channels of the energy release heat exchanger 10 and the energy release heat exchanger 12 and the inlet of the cold storage tank 15, and the heat exchange medium cooler 17 may further cool the heat exchange medium flowing out of the energy release heat exchanger 10 and the energy release heat exchanger 12, and reduce the temperature of the heat exchange medium stored in the cold storage tank 15.

As follows, an exemplary operation of the carbon dioxide energy storage system of the present invention adaptable to a wide range of storage pressures will be described with reference to the carbon dioxide energy storage system of fig. 6. In this example, the reservoir 24 is a water tank and the variable temperature heat sink assembly 300 may be a chiller subsystem.

When the user is in the electricity consumption valley, the fourth control valve 32 and the third control valve 33 are closed, the first control valve 29, the second control valve 30 and the flow control valve 31 are opened, and the energy storage part of the carbon dioxide energy storage system with a wide energy storage pressure range can be adapted to work. The carbon dioxide with normal temperature and normal pressure enters the carbon dioxide first compressor 3 after being heated in the preheater 2 by the gas storage 1, the low-valley electric power drives the carbon dioxide first compressor 3 to compress the carbon dioxide, the compressed carbon dioxide enters the carbon dioxide first heat exchanger 4 to exchange heat and cool, heat is transferred to a heat exchange medium from the cold storage tank 15, the cooled carbon dioxide enters the carbon dioxide second compressor 5, the low-valley electric power drives the carbon dioxide second compressor 5 to compress the carbon dioxide to the energy storage pressure, the carbon dioxide second compressor 5 gives an energy storage pressure signal (namely the energy storage pressure of the gaseous carbon dioxide) to the control module 18, the control module 18 calculates the condensation temperature of the gaseous carbon dioxide according to the energy storage pressure of the gaseous carbon dioxide, and sends a gaseous carbon dioxide condensation temperature instruction to the cold water unit subsystem (serving as the variable temperature cold source assembly 300), the high-pressure carbon dioxide coming out from the carbon dioxide second compressor 5 then enters the carbon dioxide second heat exchanger 6 to exchange heat and cool, the heat is transferred to the heat exchange medium coming from the cold storage tank 15, and then enters the carbon dioxide condenser 7, the cold water unit subsystem generates low-temperature water with required temperature according to the gaseous carbon dioxide condensation temperature instruction, the gaseous carbon dioxide condensation temperature instruction is condensed to the low-temperature water, and the gaseous carbon dioxide and the low-temperature is stored in the liquid carbon dioxide container 8.

The subsystem of the water chiller and the energy storage part work simultaneously. The refrigerant is compressed by the refrigerant compressor 20 and then enters the refrigerant condenser 21 to be condensed into liquid-phase refrigerant, the high-pressure liquid-phase refrigerant enters the refrigerant expansion valve 22 to be throttled and expanded, finally the refrigerant enters the refrigerant evaporator 23 to exchange heat with water from the water tank (serving as the liquid storage 24), the refrigerant absorbs heat and evaporates into gas-phase refrigerant and then enters the refrigerant compressor 20 again, the water in the water tank absorbs heat and reduces temperature to generate low-temperature water, and the low-temperature water enters the carbon dioxide condenser 7 to absorb heat and raise temperature to provide cold energy for gas-phase carbon dioxide condensation. The water after absorbing heat and raising temperature is returned to the water tank (as the reservoir 24). The operation of supplying the carbon dioxide condenser 7 with cold is completed.

One principle of operation of the control module 18 to control the chiller subsystem is:

the second compressor 5 (the last compressor) of carbon dioxide gives an energy storage pressure signal (i.e. a signal of the pressure of the gaseous carbon dioxide) to the control module 18, the control module 18 calculates the gaseous carbon dioxide condensation temperature according to the energy storage pressure, and sends a relevant instruction of the gaseous carbon dioxide condensation temperature to a chiller subsystem (e.g. a refrigerant evaporator 23), and the chiller subsystem (e.g. the refrigerant evaporator 23) produces the required cold energy according to the carbon dioxide condensation temperature, so as to control the water temperature after heat exchange from the water in the water tank 24, and further provide the cold energy required by the gaseous carbon dioxide condensation.

The water chiller subsystem may be an air-cooled water chiller or a water-cooled water chiller, and the refrigerant evaporator 23 determines the refrigerant evaporation pressure according to a temperature command (i.e., a corresponding refrigerant evaporation temperature) sent by the control module 18. The refrigerant evaporation pressure and the refrigerant condensation pressure control the refrigerant compressor 20, compressing the gas-phase refrigerant (the pressure is the evaporation pressure) coming out of the refrigerant evaporator 23 into the refrigerant compressor 20, so that the pressure of the gas-phase refrigerant increases to the refrigerant condensation pressure; the pressurized gas-phase refrigerant then enters the refrigerant condenser 21 to be condensed into a liquid-phase refrigerant. The refrigerant evaporation pressure and the refrigerant condensation pressure also control the opening degree of the refrigerant expansion valve 22 so that the liquid-phase refrigerant (the pressure is the condensation pressure) that comes out of the refrigerant condenser 21 and enters the refrigerant expansion valve 22 expands and reduces the pressure, and the reduced pressure is the refrigerant evaporation pressure. The refrigerant after expansion and depressurization enters the refrigerant evaporator 23 and evaporates into a gas-phase refrigerant.

The control module 18 may also obtain flow information of the gaseous carbon dioxide in the energy storage assembly 100, where the flow may be a flow of the gaseous carbon dioxide on a pipeline between the carbon dioxide second compressor 3 and the carbon dioxide first heat exchanger 4, or a flow of the gaseous carbon dioxide on a pipeline between the carbon dioxide first heat exchanger 4 and the carbon dioxide second compressor 5, or a flow of the gaseous carbon dioxide on a pipeline between the carbon dioxide second compressor 5 and the carbon dioxide second heat exchanger 6, or a flow of the gaseous carbon dioxide on a pipeline between the carbon dioxide second heat exchanger 6 and the carbon dioxide condenser 7. The control module 18 can control the opening of the third control valve 31 according to the carbon dioxide flow information, so as to control the flow of the refrigerant entering the refrigerant evaporator 23, thereby controlling the flow of the water in the water tank 24 for heat exchange circulation, and the electric quantity consumed by the subsystem of the water chiller is minimum and the circulating water quantity of the water tank 24 is minimum through the accurate matching of the carbon dioxide flow and the refrigerant flow.

When the user is in the power consumption peak, the first control valve 29, the second control valve 30, the fourth control valve 32 and the third control valve 33 are closed, and the energy release part of the carbon dioxide energy storage system with a wide energy storage pressure range can be adapted to work. The liquid-phase carbon dioxide in the energy storage container 8 enters a carbon dioxide evaporator 9 to be heated and evaporated into gas-phase carbon dioxide; the gaseous carbon dioxide enters the carbon dioxide third heat exchanger 10 to exchange heat with part of heat storage medium from the heat storage tank 16 to raise temperature, and the high-temperature and high-pressure carbon dioxide enters the carbon dioxide first turbine 11 to expand and do work to drive the generator to generate electricity. Then, the gas-phase carbon dioxide with medium temperature and medium pressure enters the carbon dioxide third heat exchanger 11 to exchange heat with the residual heat storage medium from the heat storage tank 16 to raise the temperature, and the carbon dioxide with high temperature and medium pressure enters the carbon dioxide second turbine 13 to continuously expand and do work so as to drive the generator to generate electricity. Finally, the carbon dioxide at low temperature and normal pressure is stored in the gas storage 1 after being cooled by the carbon dioxide cooler 14. The medium temperature heat exchange medium which is subjected to heat release and temperature reduction through the two heat exchangers is stored in the cold storage tank 15 after being subjected to heat release and temperature reduction through the heat exchange medium cooler 17. The expansion and heat release of the working medium are completed.

The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention herein. This application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.

Claims

1. The carbon dioxide energy storage system is characterized by comprising an air storage, an energy storage component, a carbon dioxide condenser, an energy storage container and an energy release component which are sequentially connected in a closed loop, and comprising a control module and a variable temperature cold source component; the outlet of the gas storage is connected with the inlet of the energy storage component, the outlet of the energy storage component is connected with the inlet of the carbon dioxide channel of the carbon dioxide condenser, and the outlet of the carbon dioxide channel of the carbon dioxide condenser is connected with the inlet of the energy storage container; the outlet of the energy storage container is connected with the inlet of the energy release assembly, and the outlet of the energy release assembly is connected with the inlet of the gas storage;

2. The carbon dioxide energy storage system of claim 1, wherein the state parameter of the gaseous carbon dioxide output by the energy storage assembly comprises an energy storage pressure of the gaseous carbon dioxide;

3. The carbon dioxide energy storage system of claim 2, wherein the state parameters of the gaseous carbon dioxide output by the energy storage assembly further comprise flow rate and temperature of the gaseous carbon dioxide;

4. The carbon dioxide energy storage system of claim 2, wherein the energy storage assembly comprises one or more energy storage heat exchange units connected in series or parallel, each comprising a carbon dioxide compressor and a carbon dioxide heat exchanger, an outlet of the carbon dioxide compressor being connected to a carbon dioxide inlet of the carbon dioxide heat exchanger; the carbon dioxide compressor in the energy storage heat exchange unit at the initial end is connected with the gas storage, the carbon dioxide heat exchanger in the energy storage heat exchange unit at the tail end is connected with the carbon dioxide condenser, and the energy storage pressure of the gas-phase carbon dioxide output by the energy storage component is the pressure of the carbon dioxide at the tail end at the carbon dioxide compressor outlet of the energy storage heat exchange unit, the carbon dioxide outlet of the carbon dioxide heat exchanger or the inlet of the carbon dioxide channel of the carbon dioxide condenser.

5. The adaptable wide energy storage pressure range carbon dioxide energy storage system of claim 1, wherein the variable temperature heat sink assembly includes a heat supplying portion and a cooling portion;

6. The carbon dioxide energy storage system adaptable to a wide range of stored energy pressures of claim 5, wherein the refrigeration portion includes a refrigerant compressor, a refrigerant condenser, a refrigerant expansion valve, and a refrigerant evaporator; an outlet of the refrigerant compressor is connected with an inlet of a refrigerant channel of the refrigerant condenser, an outlet of the refrigerant channel of the refrigerant condenser is connected with an inlet of the refrigerant expansion valve, an outlet of the refrigerant expansion valve is connected with an inlet of a refrigerant channel of the refrigerant evaporator, and an outlet of the refrigerant channel of the refrigerant evaporator is connected with an inlet of the refrigerant compressor;

7. The adaptable wide range of stored energy pressures carbon dioxide energy storage system of claim 6, wherein the control module is configured to: and controlling the opening degree of the refrigerant expansion valve according to the energy storage pressure of the gas-phase carbon dioxide output by the energy storage component.

8. The carbon dioxide energy storage system adaptable to a wide range of storage pressures of claim 6, wherein the refrigeration portion further includes a flow control valve between the refrigerant expansion valve and the refrigerant evaporator;

9. The adaptable wide range of stored energy pressure carbon dioxide energy storage system of claim 1, wherein the variable temperature heat sink assembly includes a refrigerant compressor, a refrigerant condenser, and a refrigerant expansion valve;

10. A method of controlling a carbon dioxide energy storage system adaptable to a wide range of storage pressures as claimed in any one of claims 1 to 9, comprising: