Carnot cell cold, heat, electricity and fresh water combined supply system based on waste heat utilization

Abstract

The invention discloses a carnot cell cold, heat, electricity and fresh water combined supply system based on waste heat utilization. The system comprises a dual-pressure condensation heat pump cycle device, a heat storage cycle device, an organic Rankine cycle device, a lithium bromide absorption type refrigeration cycle device, a multi-stage flash evaporation seawater desalination device and a photovoltaic power generation device. Wherein the dual-pressure condensation heat pump circulating device is respectively connected with the heat storage circulating device, the lithium bromide absorption type refrigeration circulating device, the photovoltaic power generation device and the multi-stage flash evaporation seawater desalting device; the heat storage circulating device is also connected with the organic Rankine cycle device; the lithium bromide absorption type refrigeration circulating device is also connected with the multi-stage flash evaporation seawater desalting device; and the dual-pressure condensation heat pump circulating device is used for increasing the temperature of the waste heat so as to meet the operation requirements of the lithium bromide absorption type refrigeration circulating device or the multi-stage flash evaporation seawater desalting device. A large number of low-grade waste heat resources generated in industrial production are effectively utilized, and supply and demand matching of electric energy is adjusted.

Description

Technical Field

[0001] The present invention relates to the technical field of integrated energy systems, and in particular to a Carnot battery cold, heat, electricity and fresh water co-supply system based on waste heat utilization. Background Art

[0002] According to the survey, my country's low-grade waste heat resources account for more than 60% of the total waste heat loss. Low-grade waste heat can be divided into solid (<400℃), gas (<200℃) and liquid (<90℃) forms. Among them, liquid low-grade waste heat is difficult to be directly and effectively utilized, but it is very suitable as a heat source for heat pumps for other purposes. Taking the Beijing-Tianjin-Tangshan Industrial Base in my country as an example, a large amount of low-grade waste heat has not been effectively utilized, and a large amount of electricity is also required for industrial production. In addition, the region has distinct seasons, requiring cooling in summer and heating in winter, and the region lacks fresh water resources, but is close to the ocean. A large amount of low-grade waste heat (such as liquid below 90°C) generated in the industrial process is often not effectively utilized, resulting in energy waste. According to relevant research, low-grade waste heat accounts for more than 60% of the total waste heat loss, especially in industrial bases such as Beijing-Tianjin-Tangshan, this problem is particularly prominent.

[0003] Renewable energy (such as solar energy and wind energy) is intermittent and unstable, resulting in an imbalance between electricity supply and demand; traditional energy storage technologies (such as battery energy storage) are costly and short-lived, making it difficult to meet large-scale energy storage needs. Existing multi-energy cogeneration systems can often only meet single or a few energy needs and lack comprehensive solutions. For example, existing cogeneration systems may only provide electricity and heat energy, but cannot meet the needs of cooling energy and fresh water at the same time.

[0004] Therefore, it is an urgent problem for those skilled in the art to propose a Carnot battery cold, hot, electric and fresh water cogeneration system based on waste heat utilization to solve the difficulties existing in the prior art. Summary of the invention

[0005] The purpose of the present invention is to provide a Carnot battery cold, hot, electric and fresh water co-generation system based on waste heat utilization, which effectively utilizes a large amount of low-grade waste heat resources generated in industrial production and better regulates the supply and demand matching of electric energy.

[0006] To achieve the above object, the present invention provides the following solutions: A Carnot battery cold, heat, electricity and fresh water cogeneration system based on waste heat utilization, comprising a dual-pressure condensing heat pump circulation device, a heat storage circulation device, an organic Rankine cycle device, a lithium bromide absorption refrigeration circulation device, a multi-stage flash evaporation seawater desalination device and a photovoltaic power generation device; wherein the dual-pressure condensing heat pump circulation device is connected to the heat storage circulation device, the lithium bromide absorption refrigeration circulation device, the photovoltaic power generation device and the multi-stage flash evaporation seawater desalination device respectively; the heat storage circulation device is also connected to the organic Rankine cycle device, and the lithium bromide absorption refrigeration circulation device is also connected to the multi-stage flash evaporation seawater desalination device; Double-pressure condensing heat pump circulation device, used to increase the temperature of waste heat through two-stage compression and condensation to meet the operating requirements of lithium bromide absorption refrigeration cycle device or multi-stage flash evaporation seawater desalination device; The heat storage cycle device is used to store the heat energy boosted by the dual-pressure condensing heat pump cycle device and drive the organic Rankine cycle device to generate electricity during peak electricity consumption periods; Organic Rankine cycle device, used to generate electricity using the heat energy released in the heat storage cycle device, providing more electricity to the demand side; A lithium bromide absorption refrigeration cycle device is used to utilize the heat provided by the dual-pressure condensing heat pump cycle device to provide cooling capacity to the outside world; Photovoltaic power generation device, used to generate electricity, part of which is directly supplied to the demand side, and the other part is supplied to the dual-pressure condensing heat pump circulation device to support the operation of the system; The multi-stage flash desalination device is used to desalinate seawater using the heat provided by the dual-pressure condensing heat pump cycle.

[0007] Preferably, the dual-pressure condensing heat pump circulation device includes a first heat exchanger, a low-pressure compressor, a second heat exchanger, a high-pressure compressor, a third heat exchanger, and a first circulation pump; wherein the first heat exchanger, the second heat exchanger, and the third heat exchanger are connected in parallel in sequence, a low-pressure compressor is provided on the first pipeline connecting the first heat exchanger and the second heat exchanger, and a second throttle valve is provided on the second pipeline connecting the first heat exchanger and the second heat exchanger; a high-pressure compressor is provided on the first pipeline connecting the second heat exchanger and the third heat exchanger, and a first throttle valve is provided on the second pipeline connecting the second heat exchanger and the third heat exchanger; the second heat exchanger is also connected to the first circulation pump.

[0008] Preferably, after the working fluid in the first heat exchanger absorbs the heat of low-grade waste heat, it flows to the second heat exchanger and the high-pressure compressor respectively after passing through the low-pressure compressor; the high-pressure compressor recompresses the working fluid and transmits it to the third heat exchanger; the first throttle valve reduces the pressure of the working fluid at the outlet of the third heat exchanger; the second throttle valve further reduces the pressure of the working fluid mixed at the outlet of the first throttle valve and the outlet of the second heat exchanger, and finally the working fluid returns to the first heat exchanger.

[0009] Preferably, the organic Rankine cycle device includes a fourth heat exchanger, an expander, a fifth heat exchanger, and a second circulation pump connected in sequence; the working fluid absorbs heat in the fourth heat exchanger and flows to the expander, and the working fluid expands and generates electricity in the expander and is cooled through the fifth heat exchanger, and finally returns to the fourth heat exchanger through the second circulation pump.

[0010] Preferably, the heat storage cycle device includes a high-temperature tank and a low-temperature tank, the high-temperature tank is connected to the third heat exchanger and the fourth heat exchanger, respectively, and the low-temperature tank is connected to the third heat exchanger and the fourth heat exchanger, respectively; the heat storage medium in the high-temperature tank and the low-temperature tank is water, and the water absorbs the heat of the working fluid in the third heat exchanger and is stored in the high-temperature tank; during peak electricity consumption, the heat energy in the high-temperature tank is released to drive the organic Rankine cycle device to generate electricity, and the water flows to the low-temperature tank after heat exchange in the fourth heat exchanger, and then returns to the third heat exchanger.

[0011] Preferably, the lithium bromide absorption refrigeration cycle device includes a generator, an eighth heat exchanger, a seventh heat exchanger, an absorber, a third circulation pump, a sixth heat exchanger, and a generator connected in sequence; wherein the sixth heat exchanger is also connected to the absorber, a third throttle valve is provided on the pipeline between the sixth heat exchanger and the absorber, and a fourth throttle valve is provided on the pipeline between the eighth heat exchanger and the seventh heat exchanger.

[0012] Preferably, the multi-stage flash seawater desalination device comprises a seawater desalinator and a fresh water storage tank connected in sequence.

[0013] Preferably, it also includes a heating heat exchanger, which is connected to the multi-stage flash desalination device via a third rotary valve; when heating, the third rotary valve is opened, and the heating heat exchanger utilizes the heat of the refrigerant at the outlet of the multi-stage flash desalination device.

[0014] Preferably, a first rotary valve is provided on the pipeline between the dual-pressure condensing heat pump circulation device and the lithium bromide absorption refrigeration circulation device, and a second rotary valve is provided on the pipeline between the dual-pressure condensing heat pump circulation device and the multi-stage flash evaporation seawater desalination device.

[0015] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects: The present invention provides a Carnot battery cold, heat, electricity and fresh water cogeneration system based on waste heat utilization. Unlike the traditional cogeneration system coupled heat pump, it adopts a dual-pressure condensing heat pump subsystem to achieve different energy outputs according to temperature classification. Compared with multiple independent single-stage heat pumps, this subsystem can reduce the area of ​​the heat exchanger, and the working fluid is compressed in two stages, which can effectively reduce the exhaust pressure of the compressor, thereby reducing the cost of the system. Considering that the system is in the form of thermal energy drive and its geographical location, refrigeration and water production use lithium bromide absorption refrigeration cycle and multi-stage flash seawater desalination system respectively, and Carnot battery energy storage technology is used to better balance power supply and load. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0017] Figure 1 A structural diagram of a Carnot battery cold, hot, electric and fresh water co-generation system based on waste heat utilization provided by the present invention; Among them, 1-first heat exchanger, 2-low-pressure compressor, 3-second heat exchanger, 4-high-pressure compressor, 5-third heat exchanger, 6-first throttle valve, 7-second throttle valve, 8-first circulation pump, 9-high-temperature tank, 10-low-temperature tank, 11-fourth heat exchanger, 12-expander, 13-fifth heat exchanger, 14-second circulation pump, 15-first rotary valve, 16-generator, 17-sixth heat exchanger, 18-third circulation pump, 19-absorber, 20-third throttle valve, 21-seventh heat exchanger, 22-fourth throttle valve, 23-eighth heat exchanger, 24-second rotary valve, 25-seawater desalination device, 26-fresh water storage tank, 27-third rotary valve, 28-heating heat exchanger, 29-photovoltaic power generation device. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0020] like Figure 1 As shown, the present invention provides a Carnot battery cold, heat, electricity and fresh water cogeneration system based on waste heat utilization, including a dual-pressure condensing heat pump circulation device, a heat storage circulation device, an organic Rankine cycle device, a lithium bromide absorption refrigeration circulation device, a multi-stage flash evaporation seawater desalination device and a photovoltaic power generation device; wherein the dual-pressure condensing heat pump circulation device is connected to the heat storage circulation device, the lithium bromide absorption refrigeration circulation device, the photovoltaic power generation device, and the multi-stage flash evaporation seawater desalination device respectively; the heat storage circulation device is also connected to the organic Rankine cycle device, and the lithium bromide absorption refrigeration circulation device is also connected to the multi-stage flash evaporation seawater desalination device; Double-pressure condensing heat pump circulation device, used to increase the temperature of waste heat through two-stage compression and condensation to meet the operating requirements of lithium bromide absorption refrigeration cycle device or multi-stage flash evaporation seawater desalination device; The heat storage cycle device is used to store the heat energy boosted by the dual-pressure condensing heat pump cycle device and drive the organic Rankine cycle device to generate electricity during peak electricity consumption periods; Organic Rankine cycle device, used to generate electricity using the heat energy released in the heat storage cycle device, providing more electricity to the demand side; A lithium bromide absorption refrigeration cycle device is used to utilize the heat provided by the dual-pressure condensing heat pump cycle device to provide cooling capacity to the outside world; Photovoltaic power generation device 29, used to generate electricity, a part of which is directly supplied to the demand side, and the other part is supplied to the dual-pressure condensing heat pump circulation device to support the operation of the system; The multi-stage flash desalination device is used to desalinate seawater using the heat provided by the dual-pressure condensing heat pump cycle.

[0021] Furthermore, the dual-pressure condensing heat pump circulation device includes a first heat exchanger 1, a low-pressure compressor 2, a second heat exchanger 3, a high-pressure compressor 4, a third heat exchanger 5, and a first circulation pump 8; wherein the first heat exchanger 1, the second heat exchanger 3, and the third heat exchanger 5 are connected in parallel in sequence, the low-pressure compressor 2 is arranged on the first pipeline connecting the first heat exchanger 1 and the second heat exchanger 3, and the second throttle valve 7 is arranged on the second pipeline connecting the first heat exchanger 1 and the second heat exchanger 3; the high-pressure compressor 4 is arranged on the first pipeline connecting the second heat exchanger 3 and the third heat exchanger 5, and the first throttle valve 6 is arranged on the second pipeline connecting the second heat exchanger 3 and the third heat exchanger 5; the second heat exchanger 3 is also connected to the first circulation pump 8.

[0022] Specifically, the photovoltaic power generation device 29 is respectively connected to the low-pressure compressor 2 and the high-pressure compressor 4 in the dual-pressure condensing heat pump circulation device. Part of the electric energy of the photovoltaic power generation device 29 can be directly supplied to the demand side, and the remaining electric energy is supplied to the low-pressure compressor 2 and the high-pressure compressor 4 connected thereto.

[0023] Furthermore, after the working fluid in the first heat exchanger 1 absorbs the heat of the low-grade waste heat, it flows to the second heat exchanger 3 and the high-pressure compressor 4 respectively after passing through the low-pressure compressor; the high-pressure compressor 4 recompresses the working fluid and transmits it to the third heat exchanger 5; the first throttle valve 6 reduces the pressure of the working fluid at the outlet of the third heat exchanger 5; the second throttle valve 7 further reduces the pressure of the working fluid mixed at the outlet of the first throttle valve 6 and the outlet of the second heat exchanger 3, and finally the working fluid returns to the first heat exchanger 1.

[0024] Furthermore, the organic Rankine cycle device includes a fourth heat exchanger 11, an expander 12, a fifth heat exchanger 13, and a second circulation pump 14 connected in sequence; the working fluid absorbs heat in the fourth heat exchanger 11 and flows to the expander 12. After the working fluid expands and generates electricity in the expander 12, it is cooled by the fifth heat exchanger 13 and finally returns to the fourth heat exchanger 11 through the second circulation pump 14.

[0025] Furthermore, the heat storage cycle device includes a high-temperature tank 9 and a low-temperature tank 10. The high-temperature tank 9 is connected to the third heat exchanger 5 and the fourth heat exchanger 11, respectively, and the low-temperature tank 10 is connected to the third heat exchanger 5 and the fourth heat exchanger 11, respectively; the heat storage medium in the high-temperature tank 9 and the low-temperature tank 10 is water, and the water absorbs the heat of the working fluid in the third heat exchanger 5 and is stored in the high-temperature tank 9; during peak electricity consumption, the heat energy in the high-temperature tank 9 is released to drive the organic Rankine cycle device to generate electricity, and the water flows to the low-temperature tank 10 after heat exchange through the fourth heat exchanger 11, and then returns to the third heat exchanger 5.

[0026] Specifically, the heat storage cycle device is connected to the dual-pressure condensing heat pump cycle device through the third heat exchanger 5; the heat storage cycle device is connected to the organic Rankine cycle device through the fourth heat exchanger 11; Furthermore, the lithium bromide absorption refrigeration cycle device includes a generator 16, an eighth heat exchanger 23, a seventh heat exchanger 21, an absorber 19, a third circulation pump 18, a sixth heat exchanger 17, and a generator 16 which are connected in sequence; wherein the sixth heat exchanger 17 is also connected to the absorber 19, a third throttle valve 20 is provided on the pipeline between the sixth heat exchanger 17 and the absorber 19, and a fourth throttle valve 22 is provided on the pipeline between the eighth heat exchanger 23 and the seventh heat exchanger 21.

[0027] Specifically, the refrigerant of the lithium bromide absorption refrigeration cycle device is water, and the absorbent is lithium bromide; the refrigerant evaporates and absorbs heat in the seventh heat exchanger 21, thereby providing cold to the outside. The refrigerant then enters the absorber 19 and is absorbed by the absorbent, thereby forming a dilute solution, which is then sent to the generator 16 after passing through the third circulation pump 18 and the sixth heat exchanger 17. The solution is heated in the generator 16 to generate steam and becomes a concentrated solution. The steam is condensed through the eighth heat exchanger 23 and then returns to the seventh heat exchanger 21 through the fourth throttle valve 22, while the concentrated solution passes through the sixth heat exchanger 17 to exchange heat with the dilute solution and then returns to the absorber 19 through the third throttle valve 20.

[0028] Furthermore, the multi-stage flash desalination device comprises a desalinator 25 and a fresh water storage tank 26 connected in sequence. The multi-stage flash desalination device produces water using the heat of the coolant at the outlet of the generator 16; the desalinator 25 is connected to the fresh water storage tank 26 to store fresh water.

[0029] Furthermore, the system also includes a heating heat exchanger 28, which is connected to the multi-stage flash desalination device via a third rotary valve 27; when heating, the third rotary valve 27 is opened, and the heating heat exchanger 28 utilizes the heat of the refrigerant at the outlet of the multi-stage flash desalination device.

[0030] Furthermore, a first rotary valve 15 is provided on the pipeline between the dual-pressure condensing heat pump circulation device and the lithium bromide absorption refrigeration circulation device, and a second rotary valve 24 is provided on the pipeline between the dual-pressure condensing heat pump circulation device and the multi-stage flash evaporation seawater desalination device.

[0031] In a specific embodiment, the Carnot battery cold, heat, electricity and fresh water cogeneration system based on waste heat utilization includes two typical working conditions in summer and winter. According to the corresponding season, the different subsystems or cycles are controlled by the rotary valve to operate in conjunction with each other to meet the supply on the demand side; Summer: the first rotary valve 15 is opened, the second rotary valve 24 is closed, the third rotary valve 27 is closed, and the system is operated jointly by the dual-pressure condensing heat pump circulation device, the heat storage circulation device, the organic Rankine cycle device, the lithium bromide absorption refrigeration circulation device, the multi-stage flash water desalination device and the photovoltaic power generation device 29 to provide power supply, energy storage, water production and refrigeration; Winter: the first rotary valve 15 is closed, the second rotary valve 24 is opened, and the third rotary valve 27 is opened. The system is jointly operated by a dual-pressure condensing heat pump circulation device, a heat storage circulation device, an organic Rankine cycle device, a multi-stage flash water desalination device, a heating heat exchanger 28 and a photovoltaic power generation device 29 to provide power supply, energy storage, water production and heating.

[0032] The Carnot battery cold, hot, electric and fresh water co-supply system based on waste heat utilization provided by the present invention comprises: a dual-pressure condensing heat pump circulation device, a heat storage circulation device, an organic Rankine cycle device, a lithium bromide absorption refrigeration circulation device, a multi-stage flash evaporation seawater desalination device and a photovoltaic power generation device; low-grade waste heat is used as a heat source for the dual-pressure condensing heat pump circulation, and the photovoltaic power generation device directly distributes part of the electric energy to the demand side, and the other part of the electric energy is respectively supplied to the low-pressure compressor 2 and the high-pressure compressor 4; a part of the working fluid at the outlet of the low-pressure compressor 2 flows to the second heat exchanger 3, and the low-grade waste heat is pressurized by the first circulation pump 8 and then heat-exchanged with the working fluid in the second heat exchanger 3, so that the temperature of the low-grade waste heat is increased, which can meet the requirements of the lithium bromide absorption refrigeration circulation device or the multi-stage flash evaporation seawater desalination device. Operation requirements: The purpose of pressurizing the circulating pump is to prevent energy loss caused by phase change during heat exchange of the refrigerant; another part of the working fluid at the outlet of the low-pressure compressor flows to the high-pressure compressor 4 for recompression, and then exchanges heat with the heat storage medium to achieve the purpose of electricity storage; during peak electricity consumption, the organic Rankine cycle device discharges to provide more electricity to the demand side; the waste heat after the temperature rises continues to drive the lithium bromide absorption refrigeration cycle device or the multi-stage flash desalination device, which is mainly divided into two typical working conditions in summer and winter; in summer, the lithium bromide absorption refrigeration cycle is first driven to produce cold capacity, and then the multi-stage flash desalination system is driven to produce fresh water; in winter, the multi-stage flash desalination device is first driven to produce fresh water, and the excess heat is then transported to the heating heat exchanger for heat exchange for heating. Therefore, the present invention can provide the cold, heat, electricity and fresh water needs in the Beijing-Tianjin-Tangshan industrial base, and effectively utilizes a large amount of low-grade waste heat resources generated in industrial production. In addition, the Carnot battery technology absorbs excess photovoltaic resources and better adjusts the supply and demand matching of electricity. Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0033] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A Carnot battery cold, heat, electricity and fresh water co-generation system based on waste heat utilization, characterized in that: It includes a dual-pressure condensing heat pump circulation device, a heat storage circulation device, an organic Rankine cycle device, a lithium bromide absorption refrigeration circulation device, a multi-stage flash seawater desalination device and a photovoltaic power generation device; wherein the dual-pressure condensing heat pump circulation device is connected to the heat storage circulation device, the lithium bromide absorption refrigeration circulation device, the photovoltaic power generation device and the multi-stage flash seawater desalination device respectively; the heat storage circulation device is also connected to the organic Rankine cycle device, and the lithium bromide absorption refrigeration circulation device is also connected to the multi-stage flash seawater desalination device; The dual-pressure condensing heat pump circulation device is used to increase the temperature of waste heat through two-stage compression and condensation to meet the operating requirements of a lithium bromide absorption refrigeration cycle device or a multi-stage flash evaporation seawater desalination device; The heat storage cycle device is used to store the heat energy boosted by the dual-pressure condensing heat pump cycle device and drive the organic Rankine cycle device to generate electricity during peak electricity consumption periods; The organic Rankine cycle device is used to generate electricity using the heat energy released in the heat storage cycle device to provide more electricity to the demand side; The lithium bromide absorption refrigeration cycle device is used to utilize the heat provided by the dual-pressure condensing heat pump cycle device to provide cooling capacity to the outside world; The photovoltaic power generation device is used to generate electrical energy, a part of which is directly supplied to the demand side, and the other part is supplied to the dual-pressure condensing heat pump circulation device to support the operation of the system; The multi-stage flash seawater desalination device is used to desalinate seawater using the heat provided by the dual-pressure condensing heat pump cycle.

2. According to claim 1, a Carnot battery cold, heat, electricity and fresh water co-generation system based on waste heat utilization is characterized in that: The dual-pressure condensing heat pump circulation device includes a first heat exchanger, a low-pressure compressor, a second heat exchanger, a high-pressure compressor, a third heat exchanger, and a first circulation pump; wherein the first heat exchanger, the second heat exchanger, and the third heat exchanger are connected in parallel in sequence, a low-pressure compressor is arranged on the first pipeline connecting the first heat exchanger and the second heat exchanger, and a second throttle valve is arranged on the second pipeline connecting the first heat exchanger and the second heat exchanger; a high-pressure compressor is arranged on the first pipeline connecting the second heat exchanger and the third heat exchanger, and a first throttle valve is arranged on the second pipeline connecting the second heat exchanger and the third heat exchanger; the second heat exchanger is also connected to the first circulation pump.

3. According to claim 2, a Carnot battery cold, heat, electricity and fresh water co-generation system based on waste heat utilization is characterized in that: After the working fluid in the first heat exchanger absorbs the heat of the low-grade waste heat, it flows to the second heat exchanger and the high-pressure compressor respectively after passing through the low-pressure compressor; the high-pressure compressor recompresses the working fluid and transmits it to the third heat exchanger; the first throttle valve reduces the pressure of the working fluid at the outlet of the third heat exchanger; the second throttle valve further reduces the pressure of the working fluid mixed at the outlet of the first throttle valve and the outlet of the second heat exchanger, and finally the working fluid returns to the first heat exchanger.

4. According to claim 3, a Carnot battery cold, heat, electricity and fresh water co-generation system based on waste heat utilization is characterized in that: The organic Rankine cycle device includes a fourth heat exchanger, an expander, a fifth heat exchanger, and a second circulation pump connected in sequence; the working fluid absorbs heat in the fourth heat exchanger and flows to the expander. After the working fluid expands and generates electricity in the expander, it is cooled through the fifth heat exchanger and finally returns to the fourth heat exchanger through the second circulation pump.

5. According to claim 4, a Carnot battery cold, heat, electricity and fresh water co-generation system based on waste heat utilization is characterized in that: The heat storage cycle device includes a high-temperature tank and a low-temperature tank, the high-temperature tank is connected to the third heat exchanger and the fourth heat exchanger respectively, and the low-temperature tank is connected to the third heat exchanger and the fourth heat exchanger respectively; the heat storage medium in the high-temperature tank and the low-temperature tank is water, and the water absorbs the heat of the working fluid in the third heat exchanger and is stored in the high-temperature tank; during peak electricity consumption, the heat energy in the high-temperature tank is released to drive the organic Rankine cycle device to generate electricity, and the water flows to the low-temperature tank after heat exchange in the fourth heat exchanger, and then returns to the third heat exchanger.

6. The Carnot battery cold, heat, electricity and fresh water co-generation system based on waste heat utilization according to claim 5 is characterized in that: The lithium bromide absorption refrigeration cycle device includes a generator, an eighth heat exchanger, a seventh heat exchanger, an absorber, a third circulation pump, a sixth heat exchanger, and a generator which are connected in sequence; wherein the sixth heat exchanger is also connected to the absorber, a third throttle valve is provided on the pipeline between the sixth heat exchanger and the absorber, and a fourth throttle valve is provided on the pipeline between the eighth heat exchanger and the seventh heat exchanger.

7. A Carnot battery cold, heat, electricity and fresh water co-generation system based on waste heat utilization according to claim 6, characterized in that: The multi-stage flash seawater desalination device comprises a seawater desalinator and a fresh water storage tank which are connected in sequence.

8. The Carnot battery cold, heat, electricity and fresh water co-generation system based on waste heat utilization according to claim 7 is characterized in that: It also includes a heating heat exchanger, which is connected to the multi-stage flash desalination device via a third rotary valve. When heating is provided, the third rotary valve is opened, and the heating heat exchanger utilizes the heat of the refrigerant at the outlet of the multi-stage flash desalination device.

9. A Carnot battery cold, heat, electricity and fresh water co-generation system based on waste heat utilization according to claim 8, characterized in that: A first rotary valve is provided on the pipeline between the dual-pressure condensing heat pump circulation device and the lithium bromide absorption refrigeration circulation device, and a second rotary valve is provided on the pipeline between the dual-pressure condensing heat pump circulation device and the multi-stage flash evaporation seawater desalination device.

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