Water heat storage type multi-stage heating power generation energy storage system

Abstract

A water heat storage type multi-stage heating power generation energy storage system comprises a multi-stage cooling cold storage system, a multi-stage heating heat storage system, a compressor, an expansion machine, a hydraulic power generator, a working medium pump, a circulating working medium and connecting pipelines among the multi-stage cooling cold storage system, the multi-stage heating heat storage system, the compressor, the expansion machine, the hydraulic power generator, the working medium pump and the circulating working medium. The compressor and expansion power generation circulation absorbs heat from the low-temperature heat exchanger, and the heat is released to the high-temperature heat exchanger after being boosted by the compressor to drive the hydraulic power generator to generate power. And the heat of the high-temperature heat exchanger is expanded to do work so as to drive the generator. According to the design, gradient utilization and efficient conversion of heat energy are achieved, and the overall energy storage and power generation efficiency is improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of energy storage, and particularly relates to a water thermal storage type multi-stage heating power generation energy storage system. Background Art

[0002] In the current technical field of energy storage and power generation, how to efficiently utilize energy and reduce energy loss has always been a research hotspot and difficulty. Traditional heat exchange systems often have problems such as low heat exchange efficiency and large temperature difference losses, resulting in a large amount of energy waste during the energy storage and power generation processes. In addition, key equipment such as compressors will generate a large amount of waste heat during operation. If it cannot be effectively recovered and utilized, it will not only increase the energy consumption of the system, but also have an adverse impact on the stable operation of the equipment.

[0003] To solve the above problems, the utility model proposes an innovative technical solution, which combines the design of a multi-stage heat exchanger and waste heat recovery technology. The design of the multi-stage heat exchanger realizes efficient heat exchange under a small temperature difference by optimizing the structural layout of the heat exchanger, significantly reducing the energy loss during energy storage and power generation. At the same time, the utility model also cleverly utilizes waste heat recovery technology to recover the high-temperature waste heat generated during the operation of equipment such as compressors and reuse it for preheating the power generation system, realizing the cascade utilization of energy and further improving the overall energy efficiency of the system. Summary of the Invention

[0004] The utility model provides a water thermal storage type multi-stage heating power generation energy storage system, which can realize heat exchange under a small temperature difference, reduce the heat conduction temperature difference, increase the heat storage temperature difference, and at the same time reduce the energy consumption of the water pump.

[0005] Specifically described as follows: A water thermal storage type multi-stage heating power generation energy storage system includes a multi-stage cooling and cold storage system, a multi-stage heating and heat storage system, a compressor, an expander, a hydraulic generator, a working fluid pump, a circulating working fluid, and the connecting pipes between them;

[0006] The multi-stage cooling and cold storage system includes a high-temperature cold water storage tank, a low-temperature cold water storage tank, a first cold water pump, a plurality of low-temperature heat exchangers, four valves, a cold storage medium, and the connecting pipes between them; the cold storage medium channels of the plurality of low-temperature heat exchangers are connected in series with each other, and then connected between the low-temperature cold water storage tank and the first cold water pump; the first cold water pump is connected between the low-temperature heat exchanger and the high-temperature cold water storage tank; two valves are installed between the inlet / outlet of the first cold water pump and the high-temperature cold water storage tank; two valves are installed between the inlet / outlet of the first cold water pump and the low-temperature heat exchanger;

[0007] The multi-stage heating heat storage system includes a high-temperature hot water storage tank, a low-temperature hot water storage tank, a first hot water pump, a plurality of high-temperature heat exchangers corresponding one by one to a plurality of low-temperature heat exchangers in the multi-stage cooling heat storage system, four valves, a heat storage medium, and the connecting pipes between them; the heat storage medium channels of the plurality of high-temperature heat exchangers are connected in series and then connected between the high-temperature cold water storage tank and the first hot water pump; the first hot water pump is connected between the high-temperature heat exchanger and the low-temperature cold water storage tank; two valves are installed between the inlet / outlet of the first hot water pump and the low-temperature cold water storage tank; two valves are installed between the inlet / outlet of the first hot water pump and the high-temperature heat exchanger.

[0008] A compressor, an expander, a hydraulic generator, and a working fluid pump are installed between each corresponding low-temperature heat exchanger of the multi-stage cooling heat storage system and the high-temperature heat exchanger of the multi-stage heating heat storage system; the compressor and the expander are connected in parallel between the circulating working fluid channels of the low-temperature heat exchanger and the high-temperature heat exchanger; the hydraulic generator and the working fluid pump are connected in parallel between the circulating working fluid channels of the low-temperature heat exchanger and the high-temperature heat exchanger; in this way, the low-temperature heat exchanger, the compressor, the high-temperature heat exchanger, and the hydraulic generator are connected in the above order to form a compressor cycle system; the high-temperature heat exchanger, the expander, the low-temperature heat exchanger, and the working fluid pump are connected in the above order to form an expansion power generation system.

[0009] Further, the inlet / outlet of the circulating working fluid of the compressor is respectively connected between the circulating working fluid channel of the low-temperature heat exchanger / the circulating working fluid channel of the high-temperature heat exchanger; the outlet / inlet of the circulating working fluid of the expander is respectively connected between the circulating working fluid channel of the low-temperature heat exchanger / the circulating working fluid channel of the high-temperature heat exchanger.

[0010] Further, the inlet / outlet of the circulating working fluid of the hydraulic generator is respectively connected between the circulating working fluid channel of the high-temperature heat exchanger / the circulating working fluid channel of the low-temperature heat exchanger; the inlet / outlet of the circulating working fluid of the working fluid pump is respectively connected between the circulating working fluid channel of the low-temperature heat exchanger / the circulating working fluid channel of the high-temperature heat exchanger.

[0011] Further, a second cold water pump is provided between the high-temperature cold water storage tank and the low-temperature cold water storage tank, the inlet / outlet of the second cold water pump is respectively connected to the high-temperature cold water storage tank through valves, and the outlet / inlet of the second cold water pump is respectively connected to the low-temperature cold water storage tank through valves; a second hot water pump is provided between the high-temperature hot water storage tank and the low-temperature hot water storage tank; the inlet / outlet of the second hot water pump is respectively connected to the high-temperature hot water storage tank through valves, and the outlet / inlet of the second hot water pump is respectively connected to the low-temperature hot water storage tank through valves.

[0012] Further, a first waste heat recovery heat exchanger is also provided between the compressor / expander and the circulating working fluid channel of the high-temperature heat exchanger.

[0013] Further, the other medium channels of all the first waste heat recovery heat exchangers are connected in parallel and communicate with a first circulation pump that provides circulating power for them.

[0014] Further, a second waste heat recovery heat exchanger is also provided between the hydraulic generator / working fluid pump and the circulating working fluid channel of the high-temperature heat exchanger.

[0015] Further, the other medium channels of all the second waste heat recovery heat exchangers are connected in parallel and communicate with a second circulation pump that provides circulating power.

[0016] Further, the cold storage medium is a chloride salt, such as an aqueous solution of calcium chloride, sodium chloride, magnesium chloride or ammonium chloride; the heat storage medium is water; and the circulating working fluid is freon.

[0017] The utility model has the following advantages compared with the prior art: 1) Small temperature difference heat exchange reduces losses: The design of multi-stage low-temperature heat exchangers and high-temperature heat exchangers realizes small-temperature-difference efficient heat exchange, reduces the heat conduction temperature difference, increases the heat storage temperature difference, and significantly reduces the energy loss during the energy storage / generation process; 2) Reduces the loss of the pump: By sharing one pump in multiple stages for cold storage and heat storage, the loss is significantly reduced and the efficiency is improved; 3) Waste heat utilization improves energy efficiency: Recover the superheat of the circulating working fluid during the operation of the compressor and the heat before pressure reduction to heat the preheat before the expander does work and after the circulating working fluid is pressurized, realizing cascaded utilization of energy and improving the overall energy efficiency of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present utility model. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0019] Attached Figure 1 is a structural and principle schematic diagram of the first implementation manner of power generation of the present utility model.

[0020] Attached Figure 2 is a structural and principle schematic diagram of the second implementation manner of power generation of the present utility model.

[0021] Attached Figure 3 is a structural and principle schematic diagram of the third implementation manner of power generation of the present utility model Figure 1 .

[0022] Attached Figure 4 is a structural and principle schematic diagram of the third implementation manner of power generation of the present utility model Figure 2 .

[0023] The meanings represented by the serial numbers in the above figures are as follows: 1 low-temperature heat exchanger; 2 compressor; 3 expander; 4 high-temperature heat exchanger; 5 hydraulic generator; 6 working fluid pump; 7 first waste heat recovery heat exchanger; 8 second waste heat recovery heat exchanger; 9 high-temperature cold water storage tank; 10 low-temperature cold water storage tank; 111 first cold water pump; 112 second cold water pump; 12 high-temperature hot water storage tank; 13 low-temperature hot water storage tank; 141 first hot water pump; 142 second hot water pump; 151 first circulation pump; 161 second circulation pump; 171-174 first valve-fourth valve; 191-206 fifth valve-twentieth valve. Embodiment

[0024] To make the objectives, technical solutions and advantages of the present utility model clearer, the technical solutions of the present utility model will be described in detail below.

[0025] Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments.

[0026] All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without any creative efforts fall within the scope of protection of the present utility model. To make the embodiments easier to understand, multiple embodiments or implementation methods are provided below to illustrate the relevant devices, modules, and functions of the present utility model.

[0027] To enable the readers of this embodiment to quickly understand the implementation mode of the present utility model, the working principle of the present utility model will be described below.

[0028] Embodiment 1

[0029] As shown in the Figure 1 accompanying drawings, a water energy storage type multi-stage heat generation and energy storage system includes a multi-stage cooling and cold storage system, a multi-stage heating and heat storage system, a compressor 2, an expander 3, a hydraulic generator 5, a working fluid pump 6, four valves 171-174, a circulating working fluid, and the connecting pipes therebetween.

[0030] The multi-stage cooling and cold storage system includes a high-temperature cold water storage tank 9, a low-temperature cold water storage tank 10, a first cold water pump 111, a plurality of low-temperature heat exchangers 1, four valves 191-194, a cold storage medium, and the connecting pipes therebetween; the bottom end of the high-temperature cold water tank 9 is communicated with one end of the cold storage medium channel of the first-stage low-temperature heat exchanger 1, the other end of the cold storage medium channel of the first-stage low-temperature heat exchanger 1 is communicated with one end of the cold storage medium channel of the second-stage low-temperature heat exchanger 1, the other end of the cold storage medium channel of the second-stage low-temperature heat exchanger 1 is communicated with one end of the cold storage medium channel of the third-stage low-temperature heat exchanger 1, and so on in this order until it is connected to one end of the cold storage medium channel of the last-stage low-temperature heat exchanger 1. The other end of the cold storage medium channel of the last-stage low-temperature heat exchanger 1 is communicated with the inlet / outlet of the first cold water pump 111 through the valve 193 / valve 194; the outlet / inlet of the first cold water pump 111 is communicated with the bottom end of the low-temperature cold water storage tank 10 through the valve 192 / valve 191.

[0031] The cold storage medium is an aqueous solution of chloride salts, such as aqueous solutions of calcium chloride, sodium chloride, magnesium chloride, and ammonium chloride.

[0032] The multi-stage heating and heat storage system includes a high-temperature hot water storage tank 12, a low-temperature hot water storage tank 13, a first hot water pump 141, a multi-stage high-temperature heat exchanger 4 corresponding one-to-one to the plurality of low-temperature heat exchangers 1 in the multi-stage cooling and cold storage system, four valves 199-202, a heat storage medium, and the connecting pipes therebetween; the bottom end of the high-temperature hot water storage tank 12 is communicated with one end of the heat storage medium channel of the first-stage high-temperature heat exchanger 4, the other end of the heat storage medium channel of the first-stage high-temperature heat exchanger 4 is communicated with one end of the heat storage medium channel of the second-stage high-temperature heat exchanger 4, the other end of the heat storage medium channel of the second-stage high-temperature heat exchanger 4 is communicated with one end of the heat storage medium channel of the third-stage high-temperature heat exchanger 4, and so on in this order until it is connected to one end of the energy storage medium channel of the last-stage high-temperature heat exchanger 4. The other end of the heat storage medium channel of the last-stage high-temperature heat exchanger 4 is communicated with the inlet / outlet of the first hot water pump 141 through the valve 201 / valve 202; the outlet / inlet of the first hot water pump 141 is communicated with the bottom end of the low-temperature hot water storage tank 13 through the valve 200 / valve 199.

[0033] The heat storage medium is water.

[0034] A compressor 2, an expander 3, a hydraulic generator 5, a working fluid pump 6, and four valves 171-174 are installed between each corresponding low-temperature heat exchanger 1 of the multi-stage cooling and cold storage system and the high-temperature heat exchanger 4 of the multi-stage heating and heat storage system.

[0035] The compressor 2 and the expander 3 are connected in parallel between the circulating working fluid channels of the low-temperature heat exchanger 1 and the high-temperature heat exchanger 4; the circulating working fluid inlet / outlet of the compressor 2 is respectively connected between the circulating working fluid channels of the low-temperature heat exchanger 1 / the high-temperature heat exchanger 4; the circulating working fluid outlet / inlet of the expander 3 is respectively connected between the circulating working fluid channels of the low-temperature heat exchanger 1 / the high-temperature heat exchanger 4.

[0036] The hydraulic generator 5 and the working fluid pump 6 are connected in parallel between the other ends of the circulating working fluid channels of the low-temperature heat exchanger 1 and the high-temperature heat exchanger 4; the circulating working fluid inlet / outlet of the hydraulic generator 5 is respectively connected between the circulating working fluid channels of the high-temperature heat exchanger 4 / the low-temperature heat exchanger 1; the circulating working fluid inlet / outlet of the working fluid pump 6 is respectively connected between the circulating working fluid channels of the low-temperature heat exchanger 1 / the high-temperature heat exchanger 4.

[0037] The valve 171 / valve 172 is respectively installed on the branch where the compressor 2 is located / the branch where the expander 3 is located.

[0038] The valve 173 / valve 174 is respectively installed on the branch where the working fluid pump 6 is located / the branch where the hydraulic generator 5 is located.

[0039] In this way, the low-temperature heat exchanger 1, the compressor 2, the valve 171, the high-temperature heat exchanger 4, the valve 174, and the hydraulic generator 5 are connected in the above order to form a compressor cycle system; the high-temperature heat exchanger 4, the valve 172, the expander 3, the low-temperature heat exchanger 1, the working fluid pump 6, and the valve 173 are connected in the above order to form an expansion power generation system.

[0040] The circulating working fluid is Freon.

[0041] The working cycle process of this embodiment is divided into an energy storage process and a power generation process.

[0042] The working principle of the energy storage process is as follows: Start the compressor 2, valve 171, valve 174, hydraulic generator 5, valve 191, first cold water pump 111, valve 194, valve 199, valve 202 and first hot water pump 141. The compressor cycle system connected as above, including the low-temperature heat exchanger 1, compressor 2, valve 171, high-temperature heat exchanger 4, valve 174, and hydraulic generator 5, all starts the refrigeration operation. The circulating refrigerant exchanges heat with the cold storage medium in the low-temperature heat exchanger 1, the temperature of the circulating refrigerant rises, and the temperature of the cold storage medium drops. The heated circulating refrigerant enters the compressor 2 and is compressed into a high-temperature and high-pressure gaseous state for circulation. It enters the high-temperature heat exchanger 4 to exchange heat with the heat storage medium. The heat storage medium absorbs the heat of the circulating refrigerant, and the circulating refrigerant after releasing heat becomes a low-temperature and high-pressure circulating refrigerant. The low-temperature and high-pressure circulating refrigerant directly enters the hydraulic generator 5 for power generation to achieve energy recovery and then is discharged, completing the compressor cycle. At the same time, driven by the first cold water pump 111, the cold storage medium in the high-temperature cold water tank 9 first enters the first-stage low-temperature heat exchanger 1 to exchange heat with the circulating refrigerant to complete a small temperature difference cooling, then enters the second-stage low-temperature heat exchanger 1 to exchange heat with the circulating refrigerant to complete a second small temperature difference cooling, and finally enters the last-stage low-temperature heat exchanger 1 for the last small temperature difference cooling to reach the set temperature, and then is stored in the low-temperature cold water storage tank 10 for use in the power generation process. At the same time, driven by the first hot water pump 141, the heat storage medium in the low-temperature hot water storage tank 13 first enters the last-stage high-temperature heat exchanger 4 to exchange heat with the circulating refrigerant for a small temperature difference heating, and after the heat storage medium is heated, it enters the second-to-last-stage high-temperature heat exchanger 4 to exchange heat with the circulating refrigerant for a second small temperature difference heating, and finally enters the first-stage high-temperature heat exchanger 4 for the last small temperature difference heating. After multiple small-scale temperature increases in the whole process, the high-temperature heat storage medium is stored in the high-temperature hot water storage tank 12. The above cycle is repeated continuously to complete the storage of cold and heat in the compressor cycle.

[0043] The working principle of the power generation process is as follows: Start the expander 3, valve 172, valve 173, working fluid pump 6, valve 192, valve 193, first cold water pump 111, valve 200, valve 201 and first hot water pump 141. The expansion power generation system connected in the order of the high-temperature heat exchanger 4, valve 172, expander 3, low-temperature heat exchanger 1, working fluid pump 6 and valve 173 starts power generation. The working fluid pump 6 sucks in the low-temperature and low-pressure liquid circulating working fluid from the low-temperature heat exchanger 1. Through the change in the pump cavity volume caused by its movement, the low-temperature and low-pressure liquid circulating working fluid is compressed into a low-temperature and high-pressure liquid circulating working fluid and enters the high-temperature heat exchanger 4 to exchange heat with the heat storage medium. The circulating working fluid absorbs the heat of the heat storage medium and becomes a high-temperature and high-pressure circulating working fluid to drive the expander 3 to do work and generate electricity. The circulating working fluid after doing work by the expander 3 enters the low-temperature heat exchanger 1 and is quickly cooled by the cold water in the low-temperature heat exchanger 1 to become a low-temperature and low-pressure liquid circulating working fluid for the next cycle of power generation. Such a cycle repeats continuously to complete the continuous power supply.

[0044] Through the design of the multi-stage low-temperature heat exchanger 1 and high-temperature heat exchanger 4, small temperature difference heat exchange is realized during energy storage and power generation, reducing losses.

[0045] A liquid storage tank for the circulating working fluid (not shown in the figure at this location) is also provided between the low-temperature heat exchanger 1 and the hydraulic generator 5 / working fluid pump 6, which is used for the stable liquid supply of the entire circulation system to keep the system running stably. Embodiment 2

[0046] Please refer to Figure 2 As shown, a second cold water pump 112 is provided between the high-temperature cold water storage tank 9 and the low-temperature cold water storage tank 10. The inlet / outlet of the second cold water pump 112 is respectively connected to the high-temperature cold water storage tank 9 through valves 195 / valve 196, and the outlet / inlet of the second cold water pump 112 is respectively connected to the low-temperature cold water storage tank 10 through valves 198 / valve 197; a second hot water pump 142 is provided between the high-temperature hot water storage tank 12 and the low-temperature hot water storage tank 13; the inlet / outlet of the second hot water pump 142 is respectively connected to the high-temperature hot water storage tank 12 through valves 203 and valve 204, and the outlet / inlet of the second hot water pump 142 is respectively connected to the low-temperature hot water storage tank 13 through valves 205 and valve 206. The function of the second cold water pump 112 is to be responsible for transferring the cold storage medium between the high-temperature cold water storage tank 9 and the low-temperature cold water storage tank 10; the function of the second hot water pump 142 is to be responsible for transferring the heat storage medium between the high-temperature hot water storage tank 12 and the low-temperature hot water storage tank 13.

[0047] Compared with the first embodiment, during the energy storage process, when the cold storage medium in the high-temperature cold water storage tank 9 is refrigerated by the multi-stage low-temperature heat exchanger 1 and all transferred to the low-temperature cold water storage tank 10 but still cannot reach the set temperature, the second cold water pump 112 and the second hot water pump 142 are turned on to transfer the cold storage medium in the low-temperature cold water storage tank 10 to the high-temperature cold water storage tank 9, and the heat storage medium in the high-temperature hot water storage tank 12 is transferred to the low-temperature hot water storage tank 13. Then, it is circulated again according to the working principle of the first embodiment, so that the cold storage medium and the heat storage medium reach a predetermined stability.

[0048] During the power generation process, when all the cold storage medium in the low-temperature cold water storage tank 10 is transferred to the high-temperature cold water storage tank 9 and all the heat storage medium in the high-temperature hot water storage tank 12 is transferred to the low-temperature hot water storage tank 13, the second cold water pump 112 and the second hot water pump 142 are turned on to transfer the cold storage medium in the high-temperature cold water storage tank 9 to the low-temperature cold water storage tank 10, and the heat storage medium in the low-temperature hot water storage tank 13 is transferred to the high-temperature hot water storage tank 12. Then, it is circulated again according to the power generation working principle of the first embodiment to complete the second power generation.

[0049] In this design, the addition of the second cold water pump 112 and the second hot water pump 142 can mainly reduce the number of stages of the low-temperature heat exchanger 1 and the high-temperature heat exchanger 4, achieve multiple cycles, and reach the same energy storage and power generation effects as the multi-stage low-temperature heat exchanger 1 and the high-temperature heat exchanger 4. Embodiment Three

[0050] As Figure 3 and Figure 4 shown, compared with the first and second embodiments, a first waste heat recovery heat exchanger 7 is further provided between the compressor 2 or the expander 3 and the circulating working fluid passage of the high-temperature heat exchanger 4; during the compressor cycle, the first waste heat recovery heat exchanger 7 is used to recover the heat of the superheated part of the circulating working fluid at the outlet of the compressor 2; during the expansion power generation, the heat recovered by the first waste heat recovery heat exchanger 7 during the compressor cycle is used to heat the circulating working fluid about to enter the expander 3, further increasing the temperature of the circulating working fluid for expansion power generation.

[0051] A second waste heat recovery heat exchanger 8 is further provided between the hydraulic generator 5 and the working fluid pump 6 and the circulating working fluid passage of the high-temperature heat exchanger 4; during the compressor cycle, the second waste heat recovery heat exchanger 8 is used to recover the heat of the circulating working fluid coming out of the high-temperature heat exchanger 4; during the expansion power generation, the heat recovered by the second waste heat recovery heat exchanger 8 during the compressor cycle is used for preheating the circulating working fluid before it enters the high-temperature heat exchanger 4.

[0052] The other medium channels of all the first waste heat recovery heat exchangers 7 are connected in parallel and communicated with the first circulating pump 151, and the first circulating pump 151 provides circulating power for them.

[0053] All the other medium channels of the second waste heat recovery heat exchanger 8 are connected in parallel and communicated with the second circulation pump 161; the second circulation pump 161 provides the circulation power for it.

[0054] Through the design of the first waste heat recovery heat exchanger 7, the heat of the superheated part of the circulating working medium at the outlet of the compressor 2 is recovered, and at the same time, it can be used for heating the circulating working medium during the expansion power generation process to further increase the temperature of the circulating working medium; through the design of the second waste heat recovery heat exchanger 8, the heat of the circulating working medium coming out of the high-temperature heat exchanger 4 in the compressor cycle is recovered, and at the same time, it can be used for preheating the circulating working medium during the expansion power generation process.

[0055] As described above, the other medium (waste heat recovery medium) channel of the second waste heat recovery heat exchanger 8 is communicated with the other medium (waste heat recovery medium) channel of the first waste heat recovery heat exchanger 7. Through the combined design of the first waste heat recovery heat exchanger 7 and the second waste heat recovery heat exchanger 8, during the compressor cycle, the waste heat recovery medium first passes through the second waste heat recovery heat exchanger 8 to recover the heat of the circulating working medium coming out of the high-temperature heat exchanger 4, then enters the first waste heat recovery heat exchanger 7 to recover the heat of the superheated part of the circulating working medium at the outlet of the compressor 2 again, and finally is stored; during the expansion power generation cycle, the stored high-temperature waste heat recovery medium first exchanges heat with the circulating working medium in another channel through the first waste heat recovery heat exchanger 7 to further increase the temperature of the circulating working medium. After the temperature of the waste heat recovery medium drops, it enters the second waste heat recovery heat exchanger 8 to be used for preheating the circulating working medium during the expansion power generation cycle. Finally, the waste heat recovery medium is stored again after the temperature drops again.

[0056] The operation of other components in this embodiment is the same as that in the first embodiment and the second embodiment.

[0057] The above-mentioned low-temperature heat exchanger, high-temperature heat exchanger, and two waste heat recovery heat exchangers are all countercurrent heat exchangers.

[0058] In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0059] It can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A water heat storage type multi-stage heating power generation energy storage system, characterized in that: It includes a multi-stage cooling cold storage system, a multi-stage heating heat storage system, a compressor, an expander, a hydraulic generator, a working fluid pump, a circulating working fluid and connecting pipes therebetween; The multi-stage cooling cold storage system includes a high-temperature cold water storage tank, a low-temperature cold water storage tank, a first cold water pump, a plurality of low-temperature heat exchangers, four valves, a cold storage medium and connecting pipes therebetween; the cold storage medium channels of the plurality of low-temperature heat exchangers are connected in series with each other and then connected between the low-temperature cold water storage tank and the first cold water pump; the first cold water pump is connected between the low-temperature heat exchanger and the high-temperature cold water storage tank; two valves are installed between the inlet / outlet of the first cold water pump and the high-temperature cold water storage tank; two valves are installed between the inlet / outlet of the first cold water pump and the low-temperature heat exchanger; The multi-stage heating heat storage system includes a high-temperature hot water storage tank, a low-temperature hot water storage tank, a first hot water pump, a plurality of high-temperature heat exchangers corresponding to the plurality of low-temperature heat exchangers in the multi-stage cooling cold storage system, four valves, a heat storage medium and connecting pipes therebetween; the heat storage medium channels of the plurality of high-temperature heat exchangers are connected in series with each other and then connected between the high-temperature cold water storage tank and the first hot water pump; the first hot water pump is connected between the high-temperature heat exchanger and the low-temperature cold water storage tank; two valves are installed between the inlet / outlet of the first hot water pump and the low-temperature cold water storage tank; two valves are installed between the inlet / outlet of the first hot water pump and the high-temperature heat exchanger; A compressor, an expander, a hydraulic generator and a working fluid pump are installed between each one-to-one corresponding low-temperature heat exchanger of the multi-stage cooling cold storage system and the high-temperature heat exchanger of the multi-stage heating heat storage system; the compressor and the expander are connected in parallel between the circulating working fluid channel of the low-temperature heat exchanger and the circulating working fluid channel of the high-temperature heat exchanger; the hydraulic generator and the working fluid pump are connected in parallel between the circulating working fluid channel of the low-temperature heat exchanger and the circulating working fluid channel of the high-temperature heat exchanger; in this way, the low-temperature heat exchanger, the compressor, the high-temperature heat exchanger and the hydraulic generator are connected in the above order to form a compressor circulation system; the high-temperature heat exchanger, the expander, the low-temperature heat exchanger and the working fluid pump are connected in the above order to form an expansion power generation system.

2. A water heat storage type multi-stage heating power generation energy storage system according to claim 1, characterized in that: The circulating working fluid inlet / outlet of the compressor is respectively connected between the circulating working fluid channel of the low-temperature heat exchanger / the circulating working fluid channel of the high-temperature heat exchanger; the circulating working fluid outlet / inlet of the expander is respectively connected between the circulating working fluid channel of the low-temperature heat exchanger / the circulating working fluid channel of the high-temperature heat exchanger.

3. A water heat storage type multi-stage heating power generation energy storage system according to claim 1, characterized in that: The circulating working fluid inlet / outlet of the hydraulic generator is respectively connected between the circulating working fluid channel of the high-temperature heat exchanger / the circulating working fluid channel of the low-temperature heat exchanger; the circulating working fluid inlet / outlet of the working fluid pump is respectively connected between the circulating working fluid channel of the low-temperature heat exchanger / the circulating working fluid channel of the high-temperature heat exchanger.

4. A water heat storage type multi-stage heating power generation energy storage system according to claim 1, characterized in that: A second cold water pump is provided between the high-temperature cold water storage tank and the low-temperature cold water storage tank, and the inlet / outlet of the second cold water pump is connected to the high-temperature cold water storage tank through a valve, and the outlet / inlet of the second cold water pump is connected to the low-temperature cold water storage tank through a valve; a second hot water pump is provided between the high-temperature hot water storage tank and the low-temperature hot water storage tank; the inlet / outlet of the second hot water pump is connected to the high-temperature hot water storage tank through a valve, and the outlet / inlet of the second hot water pump is connected to the low-temperature hot water storage tank through a valve.

5. A water heat storage type multi-stage heating power generation energy storage system according to claim 1, characterized in that: A first waste heat recovery heat exchanger is also provided between the compressor / expander and the circulating working medium channel of the high-temperature heat exchanger.

6. A water heat storage type multi-stage heating power generation energy storage system according to claim 5, characterized in that: The other medium channels of all the first waste heat recovery heat exchangers are connected in parallel and communicated with the first circulation pump that provides circulation power therefor.

7. A water heat storage type multi-stage heating, power generation and energy storage system according to claim 1, characterized in that: A second waste heat recovery heat exchanger is also provided between the hydraulic generator / working fluid pump and the circulating working fluid channel of the high-temperature heat exchanger.

8. A water heat storage type multi-stage heating, power generation and energy storage system according to claim 7, characterized in that: The other medium channels of all the second waste heat recovery heat exchangers are connected in parallel and communicated with the second circulation pump that provides circulation power.

9. A water heat storage type multi-stage heating, power generation and energy storage system according to claim 1, characterized in that: The cold storage medium is a chloride salt, such as an aqueous solution of calcium chloride, sodium chloride, magnesium chloride or ammonium chloride; the heat storage medium is water; and the circulating working fluid is Freon.

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