A combined cooling, heating and power energy storage system using compression heat

Abstract

The present invention discloses a combined cooling, heating, and power energy storage system utilizing compression heat. The system includes a working medium circuit, a heat storage medium circuit, an absorption refrigeration circuit, and an ejector refrigeration circuit. The system requires no additional energy during energy storage and release. The system couples absorption refrigeration and ejector refrigeration to increase cooling capacity for users, and is equipped with multiple heat exchangers to increase heat capacity for users, simultaneously meeting users' needs for cooling, heating, and power supply, thus providing a wide range of applications. The turbine and compressor are arranged in multiple stages, each followed by a heat exchanger, improving both turbine and heat exchanger efficiency. The multiple circuits in the system can be flexibly arranged according to actual needs. The system of the present invention can achieve combined cooling, heating, and power generation, and has the advantages of simple operating conditions, high energy conversion efficiency, and minimal geographical requirements, resulting in high economic benefits.

Description

Technical Field

[0001] The present invention belongs to the technical field of energy storage, and in particular relates to a combined cooling, heating and power energy storage system utilizing compression heat. Background Art

[0002] From ancient times to the present, all human activities have relied on energy. From food, clothing, housing, transportation, to entertainment and recreation, all consume a certain amount of energy, directly or indirectly. With changes in production and lifestyles and the development of industry, energy demand has increased year by year. Against the backdrop of peaks and valleys in energy demand and the randomness, intermittency, and volatility of renewable energy sources such as wind power and photovoltaics, energy storage technology has attracted worldwide attention.

[0003] Energy storage systems can shift peaks and valleys by scheduling electricity over time, effectively resolving the conflict between continuous power generation and intermittent electricity demand. This ensures stable operation of electricity across the generation, grid, and user sides, while also facilitating the integration and deployment of renewable energy. Current energy storage systems primarily include physical energy storage (pumped hydro, compressed gas storage, flywheel storage, etc.), chemical energy storage (lead-acid batteries, redox flow batteries, lithium-ion batteries, etc.), and electromagnetic energy storage (superconducting electromagnetic energy storage, supercapacitor storage, etc.). Physical storage offers large capacity and long lifespan, but site selection is highly dependent on geographical conditions, making equipment miniaturization difficult. Chemical storage has a simple structure and fast response, but also has a short lifespan and lower safety and reliability. Electromagnetic storage offers fast charge and discharge and a high number of cycles, but suffers from high investment costs and certain self-discharge losses. Furthermore, current energy storage systems are relatively limited in functionality and cannot meet user needs for heating and cooling.

[0004] Therefore, there is an urgent need to develop an energy storage system that has a simple structure, has low requirements on geographical conditions, and can simultaneously meet the various needs of users. Summary of the Invention

[0005] In response to the shortcomings of the existing technology, the present invention provides a trigeneration energy storage system for cooling, heating and electricity using compression heat, which can simultaneously meet users' various needs for cooling, heating and electricity, and can achieve comprehensive and efficient utilization of energy. It has the advantages of simple structure, large energy storage capacity and high energy conversion efficiency.

[0006] The present invention is achieved by adopting the following technical solutions:

[0007] A combined cooling, heating and power energy storage system utilizing compression heat, comprising a gas storage device, a compressor, a liquid storage device, a turbine, an evaporator, a heat storage tank and a cold storage tank;

[0008] The gas storage device stores a gaseous working medium. During the energy storage process, the working medium flows out of the gas storage device and is compressed into a high-temperature, high-pressure gas by a compressor driven by the electrical energy to be stored. The gas is then isobarically cooled to a liquid state and stored in the liquid storage device. During the energy release process, the liquid working medium flows out of the liquid storage device and isobarically heated to a gaseous state. The gas expands and performs work in the turbine, which drives the generator to generate electricity. After passing through the turbine, the working medium returns to the gas storage device, thus forming a working medium circuit.

[0009] The cold storage tank stores a heat storage medium with a lower temperature. During the energy storage process, the heat storage medium flows out from the outlet of the cold storage tank and exchanges heat with the high-temperature and high-pressure working medium at the compressor outlet. After absorbing the heat of the working medium, it is converted into a heat storage medium with a higher temperature and stored in the heat storage tank. During the energy release process, the heat storage medium flows out from the outlet of the heat storage tank and exchanges heat with the working medium entering the turbine. After transferring the heat to the working medium, it is converted into a heat storage medium with a lower temperature and returns to the cold storage tank, thus forming a heat storage medium loop.

[0010] A further improvement of the present invention is that the compressor adopts a multi-stage arrangement, and a heat exchanger is arranged after each compressor stage.

[0011] A further improvement of the present invention is that the turbine adopts a multi-stage coaxial arrangement, and a heat exchanger is arranged before each turbine stage. The first-stage heat exchanger is used to evaporate the liquid working medium into gas, and the remaining heat exchangers are used to increase the working medium temperature at the turbine inlet.

[0012] A further improvement of the present invention is that, in the heat storage medium circuit, the heat storage medium flowing out of the heat exchanger before the low-temperature stage turbine directly enters the cold storage tank, and the heat storage medium flowing out of the heat exchanger before the high-temperature stage turbine enters the same pipeline and enters the heat supply heat exchanger. The waste heat of the heat storage medium is used to provide heat to the user, and then returns to the cold storage tank after passing through the heat supply heat exchanger.

[0013] A further improvement of the present invention is that, in the heat storage medium circuit, an absorption refrigeration circuit is arranged between the heat storage tank and the pre-turbine heat exchanger to meet the user's demand for cooling capacity.

[0014] A further improvement of the present invention is that, in the heat storage medium circuit, an absorption refrigeration generator is arranged between the heat storage tank and the heat exchanger before the turbine. The heat storage medium in the heat storage tank serves as the working heat source of the absorption refrigeration, providing the heat required for the evaporation of the refrigerant in the absorption refrigeration circuit.

[0015] A further improvement of the present invention is that, in the absorption refrigeration circuit, a heat exchanger is arranged between the generator and the evaporator.

[0016] A further improvement of the present invention is that, in the working medium circuit, an ejection refrigeration circuit is arranged between the last stage turbine and the gas storage device to further meet the user's demand for cooling capacity.

[0017] A further improvement of the present invention is that the working medium is ammonia or carbon dioxide.

[0018] A further improvement of the present invention is that the heat storage medium is thermal oil;

[0019] In the working medium circuit, a steam generator for jet refrigeration is arranged between the last stage turbine and the gas storage device. The working medium after passing through the turbine serves as the working heat source of the jet refrigeration, providing the heat required for the evaporation of the refrigerant in the jet refrigeration circuit.

[0020] In the working medium circuit, a heat exchanger is arranged between the steam generator and the gas storage device, which uses the waste heat of the working medium flowing out of the steam generator to provide heat to users, further improving energy utilization and increasing the heating capacity of the system.

[0021] The present invention has at least the following beneficial technical effects:

[0022] 1. The present invention discloses a combined cooling, heating, and power energy storage system that utilizes heat of compression. By introducing a heat storage medium circuit, the heat of compression generated during the compression of the working medium is stored and used to heat the working medium to a gaseous state, providing a working heat source for the absorption refrigeration circuit. The working heat source required for the ejection refrigeration circuit is the working medium after passing through the turbine. During the energy storage process, the system only needs to provide the electrical energy to be stored. During the energy release process, the heat required is completely provided by the heat storage medium, requiring no additional energy and simplifying the system's operating conditions.

[0023] 2. The present invention discloses a combined cooling, heating, and power energy storage system utilizing heat of compression. The energy storage system simultaneously couples absorption refrigeration and ejection refrigeration to provide cooling to users. The heat storage medium flowing out of the first-stage pre-turbine heat exchanger flows directly into the cold storage tank. The heat storage medium flowing out of the remaining pre-turbine heat exchangers flows into the same pipeline, passes through the heat exchanger, and then returns to the cold storage tank after providing heat to the user. A heat exchanger is arranged between the steam generator and the gas storage device, utilizing the waste heat of the working medium to provide heat to the user. The energy storage system of the present invention fully utilizes the heat of the working medium and the heat storage medium, achieving high energy utilization and overall system efficiency. It can also meet users' diverse needs for cooling, heating, and power supply, and has a wide range of applications.

[0024] 3. The present invention provides a combined cooling, heating, and power energy storage system that utilizes compression heat. The compressor is arranged in a multi-stage configuration, and the turbine is arranged in a multi-stage coaxial configuration. A heat exchanger is arranged after each compressor stage to transfer the heat of the working medium to the heat storage medium. This not only reduces the work required to compress the working medium to the same pressure, but also allows for more gas to be compressed while consuming the same amount of electrical energy. Furthermore, compared to a single heat exchanger, the multi-heat exchanger model has a higher heat exchange efficiency. A heat exchanger is arranged before each turbine stage. Except for the first-stage pre-turbine heat exchanger, which is used to heat the liquid working medium into a gaseous state, the remaining heat exchangers serve the purpose of reheating, thereby improving the efficiency of the turbine and the heat exchanger. The multi-stage compressor configuration, the multi-stage coaxial turbine configuration, and the multi-stage heat exchange increase the amount of heat exchange between the working medium circuit and the heat storage medium circuit, resulting in high efficiency in energy storage and release for the system.

[0025] 4. The present invention provides a combined cooling, heating and power energy storage system utilizing compression heat. The system includes a working medium circuit, a heat storage medium circuit, an absorption refrigeration circuit and an ejection refrigeration circuit. The equipment in each circuit can be flexibly arranged according to actual needs, and the system has low requirements on geographical conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the structure of a combined cooling, heating and power energy storage system using compression heat proposed by the present invention.

[0027] Description of reference numerals:

[0028] 1. Gas storage device; 2. First-stage compressor; 3. Second-stage compressor; 4. Third-stage compressor; 5. First heat exchanger; 6. Second heat exchanger; 7. Third heat exchanger; 8. First condenser; 9. Liquid storage device; 10. First-stage turbine; 11. Second-stage turbine; 12. Third-stage turbine; 13. Fourth heat exchanger; 14. Fifth heat exchanger; 15. Sixth heat exchanger; 16. Steam generator; 17. Seventh heat exchanger; 18. Heat storage tank; 19. Generator; 20. Eighth heat exchanger; 21. First throttle valve; 22. First evaporator; 23. Absorber; 24. Solution pump; 25. Second throttle valve; 26. Ninth heat exchanger; 27. Tenth heat exchanger; 28. Cold storage tank; 29. ​​Second condenser; 30. Third throttle valve; 31. Second evaporator; 32. Ejector. DETAILED DESCRIPTION

[0029] To make the purpose, technical effects, and technical solutions of the embodiments of the present invention more clear, the present invention is described in detail below with reference to the embodiments and drawings. The scope of protection of the present invention is not limited to the embodiments, and any modifications made by those skilled in the art within the scope defined by the claims also fall within the scope of protection of the present invention.

[0030] See also Figure 1In one embodiment of the present invention, a combined cooling, heating, and power energy storage system utilizing heat of compression uses carbon dioxide as the working medium, thermal oil as the heat storage medium, ammonia as the absorption refrigerant, and water as the injection refrigerant. The system includes a carbon dioxide circuit assembly, a thermal oil circuit assembly, an absorption refrigeration circuit assembly, and an injection refrigeration circuit assembly.

[0031] The carbon dioxide circuit assembly specifically includes:

[0032] The outlet of the gas storage device 1 is connected to the inlet of the first-stage compressor 2, the inlet of the first-stage compressor 2 is connected to the inlet of the first flow channel of the first heat exchanger 5, the outlet of the first flow channel of the first heat exchanger 3 is connected to the inlet of the second-stage compressor 3, the outlet of the second-stage compressor 3 is connected to the inlet of the first flow channel of the second heat exchanger 6, the outlet of the first flow channel of the second heat exchanger 6 is connected to the inlet of the third-stage compressor 4, the outlet of the third-stage compressor 4 is connected to the inlet of the first flow channel of the third heat exchanger 7, the outlet of the first flow channel of the third heat exchanger 7 is connected to the inlet of the first condenser 8, the outlet of the first condenser 8 is connected to the inlet of the liquid storage device 9, and the outlet of the liquid storage device 9 is connected to the inlet of the second flow channel of the fourth heat exchanger 13 The second flow channel outlet of the fourth heat exchanger 13 is connected to the inlet of the first-stage turbine 10, the outlet of the first-stage turbine 10 is connected to the second flow channel inlet of the fifth heat exchanger 14, the second flow channel outlet of the fifth heat exchanger 14 is connected to the inlet of the second-stage turbine 11, the outlet of the second-stage turbine 11 is connected to the second flow channel inlet of the sixth heat exchanger 15, the second flow channel outlet of the sixth heat exchanger 15 is connected to the inlet of the third-stage turbine 12, the outlet of the third-stage turbine 12 is connected to the second flow channel inlet of the steam generator 16, the second flow channel outlet of the steam generator 16 is connected to the first flow channel inlet of the seventh heat exchanger 17, and the first flow channel outlet of the seventh heat exchanger 17 is connected to the inlet of the gas storage device 1.

[0033] The thermal oil circuit assembly specifically includes:

[0034] The outlet of the heat storage tank 18 is connected to the first flow channel inlet of the generator 19, the first flow channel outlet of the generator 19 is connected to the first flow channel inlets of the fourth heat exchanger 13, the fifth heat exchanger 14, and the sixth heat exchanger 15, the first flow channel outlet of the fourth heat exchanger 13 is connected to the inlet of the cold storage tank 27, the first flow channel outlets of the fifth heat exchanger 14 and the sixth heat exchanger 15 are connected to the second flow channel inlet of the tenth heat exchanger 27, the second flow channel outlet of the tenth heat exchanger 27 is connected to the inlet of the cold storage tank 28, the outlet of the cold storage tank 28 is connected to the second flow channel inlets of the first heat exchanger 5, the second heat exchanger 6, and the third heat exchanger 7, and the second flow channel outlets of the first heat exchanger 5, the second heat exchanger 6, and the third heat exchanger 7 are connected to the inlet of the heat storage tank 18.

[0035] The absorption refrigeration circuit assembly specifically includes:

[0036] The second flow channel outlet of the generator 19 is connected to the first flow channel inlet of the ninth heat exchanger 26 and the second flow channel inlet of the eighth heat exchanger 20, the first flow channel outlet of the ninth heat exchanger 26 is connected to the inlet of the absorber 23, the second flow channel outlet of the eighth heat exchanger 20 is connected to the second flow channel inlet of the first evaporator 22, the second flow channel outlet of the first evaporator 22 is connected to the inlet of the absorber 23, the outlet of the absorber 23 is connected to the inlet of the solution pump 24, the outlet of the solution pump 24 is connected to the second flow channel inlet of the ninth heat exchanger 26, and the second flow channel outlet of the ninth heat exchanger 26 is connected to the second flow channel inlet of the generator 19.

[0037] The ejection refrigeration circuit assembly specifically comprises:

[0038] The outlet of the second condenser 29 is connected to the first flow channel inlet of the second evaporator 31 and the first flow channel inlet of the steam generator 16. The first flow channel outlet of the second evaporator 31 is connected to the mixing chamber inlet of the ejector 32. The first flow channel outlet of the steam generator 16 is connected to the nozzle inlet of the ejector 32. The outlet of the diffusion chamber of the ejector 32 is connected to the inlet of the second condenser 29.

[0039] A first throttle valve 21 is provided between the outlet of the second flow channel of the eighth heat exchanger 20 and the inlet of the second flow channel of the first evaporator 22 .

[0040] A second throttle valve 25 is provided between the outlet of the first flow channel of the ninth heat exchanger 26 and the inlet of the absorber 23 .

[0041] A third throttle valve 30 is provided between the outlet of the second condenser 29 and the inlet of the first flow channel of the second evaporator 31 .

[0042] An embodiment of the present invention provides a combined cooling, heating, and power energy storage system utilizing compression heat. The system includes an energy storage process and an energy release process, specifically including the following steps:

[0043] During the energy storage process, gaseous carbon dioxide flows out of the gas storage device 1 and enters the multi-stage compressors 2, 3, and 4 in sequence for compression. Heat exchangers 5, 6, and 7 are arranged after each stage of the compressor to transfer the heat of the carbon dioxide to the thermal oil. The carbon dioxide is then condensed into liquid by isobaric cooling in the condenser 8 and stored in the liquid storage device 9. The thermal oil with a lower temperature is stored in the cold storage tank 28. After passing through the heat exchangers 5, 6, and 7, the temperature is increased and stored in the heat storage tank 28, thus completing the energy storage process.

[0044] During the energy release process, liquid carbon dioxide flows out of the liquid storage device 9, absorbs heat from the thermal oil in the fourth heat exchanger 13, vaporizes, and then enters the first-stage turbine 10 to expand and perform work. It passes through the fifth heat exchanger 14, the second-stage turbine 11, the sixth heat exchanger 15, and the third-stage turbine 12 in sequence. The fifth heat exchanger 14 and the sixth heat exchanger 15 play a reheating role. After passing through the turbine stage, it flows into the steam generator 16 to provide a working heat source for the jet refrigeration. After flowing out of the steam generator 16, it enters the seventh heat exchanger 17 to provide heat to the user, and finally returns to the gas storage device 1.

[0045] In the heat transfer oil circuit, high-temperature heat transfer oil flows out of the heat storage tank 18, passes through the generator 19, and then enters the fourth heat exchanger 13, the fifth heat exchanger 14, and the sixth heat exchanger 15. Since the low-temperature carbon dioxide liquid needs to be vaporized in the fourth heat exchanger 13, the outlet heat transfer oil temperature is relatively low. Therefore, the heat transfer oil directly returns to the cold storage tank 28 after flowing out of the fourth heat exchanger 13. The fifth heat exchanger 14 and the sixth heat exchanger 15 play a reheating role, and the outlet heat transfer oil still has a certain temperature. Therefore, the heat transfer oil flows out of the fifth heat exchanger 14 and the sixth heat exchanger 15 into the same pipeline, supplies heat to users in the tenth heat exchanger 27, and then returns to the cold storage tank 28.

[0046] In the absorption refrigeration circuit, heat from the heat transfer oil is absorbed in the generator 19, and the ammonia in the ammonia solution evaporates into ammonia vapor, enters the eighth heat exchanger 20 and condenses into liquid. At the same time, the heat released during the condensation process is used to supply heat to the user. After the liquid ammonia flows out of the eighth heat exchanger 20, it is re-depressurized to the evaporation pressure through the first throttle valve 21, and enters the first evaporator 22 to absorb heat at the user end, provide cooling to the user, and is activated to ammonia vapor; the ammonia solution remaining in the generator 19 after the generation process is reduced to the evaporation pressure after passing through the ninth heat exchanger 26 and the second throttle valve 25 and enters the absorber, absorbs the low-pressure ammonia vapor flowing out of the first evaporator 22 and then returns to the initial concentration, and then passes through the solution pump 24 and the ninth heat exchanger 26 in sequence and returns to the generator 19, thereby completing the absorption refrigeration circuit.

[0047] In the jet refrigeration circuit, after the liquid water flows out of the second condenser 29, a part of it enters the steam generator 16 to absorb the heat of the carbon dioxide gas and is converted into high-temperature steam, and then enters the nozzle of the ejector 32 for adiabatic expansion, and forms a local low-pressure area at the nozzle outlet; the other part enters the second evaporator 31 after being reduced in pressure by the third throttle valve 30, absorbs the heat from the user end in the second evaporator 31 and is converted into low-pressure water vapor. At the same time, it is sucked into the mixing chamber in the ejector by the suction effect of the low-pressure area at the nozzle outlet, and finally is ejected from the diffusion chamber and returns to the second condenser 29 to be converted into liquid water again, thereby completing the jet refrigeration circuit.

[0048] This energy storage system introduces a thermal oil circuit to store the compression heat generated during the compression of carbon dioxide during energy storage, and uses it to heat the carbon dioxide into a gaseous state during the energy release process, providing a working heat source for the absorption refrigeration circuit. The working heat source required for the injection refrigeration circuit is carbon dioxide gas with a certain temperature after passing through the turbine. During the energy storage process, the system only needs to provide the electrical energy to be stored, and the heat required during the energy release process is completely provided by the thermal oil, without the need for additional energy. The system drives the generator through the turbine to provide electrical energy to the user, provides heat to the user through the seventh heat exchanger 17, the eighth heat exchanger 20 and the tenth heat exchanger 27, and provides cooling to the user through the first evaporator 22 and the second evaporator 31, thereby realizing the trigeneration of heat, cooling and electricity of the system to meet the various needs of users. At the same time, the multiple circuits of the system can be flexibly arranged, reducing the limitations of geographical conditions.

[0049] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0050] The above only illustrates the embodiments of the present invention, but does not constitute the entire protection scope of the present invention. Ordinary technicians in the field can still modify or replace the specific implementation methods of the present invention. Any modifications or equivalent replacements that do not depart from the spirit and scope of the present invention are within the scope of protection of the claims of the present invention to be approved.

Claims

1. A combined cooling, heating and power energy storage system utilizing compression heat, characterized in that: Including gas storage device, compressor, liquid storage device, turbine, evaporator, heat storage tank and cold storage tank; The gas storage device stores a gaseous working medium. During the energy storage process, the working medium flows out of the gas storage device and is compressed into a high-temperature, high-pressure gas by a compressor driven by the electrical energy to be stored. The gas is then isobarically cooled to a liquid state and stored in the liquid storage device. During the energy release process, the liquid working medium flows out of the liquid storage device and isobarically heated to a gaseous state. The gas expands and performs work in the turbine, which drives the generator to generate electricity. After passing through the turbine, the working medium returns to the gas storage device, thus forming a working medium circuit. The cold storage tank stores a low-temperature heat storage medium. During the energy storage process, the heat storage medium flows out of the cold storage tank outlet and exchanges heat with the high-temperature and high-pressure working medium at the compressor outlet. After absorbing the heat of the working medium, it is converted into a higher-temperature heat storage medium and stored in the heat storage tank. During the energy release process, the heat storage medium flows out of the heat storage tank outlet and exchanges heat with the working medium entering the turbine. After transferring heat to the working medium, it is converted into a lower-temperature heat storage medium and returns to the cold storage tank, thus forming a heat storage medium loop. The compressor adopts a multi-stage arrangement, and a heat exchanger is arranged after each compressor stage; The turbine adopts a multi-stage coaxial arrangement, with heat exchangers arranged before each turbine stage. The first-stage heat exchanger is used to evaporate the liquid working medium into gas, and the remaining heat exchangers are used to increase the working medium temperature at the turbine inlet; In the heat storage medium circuit, the heat storage medium flowing out of the heat exchanger before the low-temperature stage turbine directly enters the cold storage tank, and the heat storage medium flowing out of the heat exchanger before the high-temperature stage turbine enters the same pipeline and enters the heat supply heat exchanger. The waste heat of the heat storage medium is used to provide heat to the user, and then returns to the cold storage tank after passing through the heat supply heat exchanger. In the heat storage medium circuit, an absorption refrigeration circuit is arranged between the heat storage tank and the pre-turbine heat exchanger to meet the user's demand for cooling capacity; In the heat storage medium circuit, an absorption refrigeration generator is arranged between the heat storage tank and the heat exchanger before the turbine. The heat storage medium in the heat storage tank is the working heat source of the absorption refrigeration, providing the heat required for the evaporation of the refrigerant in the absorption refrigeration circuit; In the working medium circuit, an ejection refrigeration circuit is arranged between the last stage turbine and the gas storage device to further meet the user's demand for cooling capacity.

2. The cooling, heating and power trigeneration energy storage system utilizing compression heat according to claim 1, characterized in that: In an absorption refrigeration circuit, a heat exchanger is arranged between the generator and the evaporator.

3. The cooling, heating and power trigeneration energy storage system using compression heat according to claim 1, characterized in that: The working medium is ammonia or carbon dioxide.

4. The cooling, heating and power trigeneration energy storage system utilizing compression heat according to claim 1, characterized in that: The heat storage medium is thermal oil; In the working medium circuit, a steam generator for jet refrigeration is arranged between the last stage turbine and the gas storage device. The working medium after passing through the turbine serves as the working heat source of the jet refrigeration, providing the heat required for the evaporation of the refrigerant in the jet refrigeration circuit. In the working medium circuit, a heat exchanger is arranged between the steam generator and the gas storage device, which uses the waste heat of the working medium flowing out of the steam generator to provide heat to users, further improving energy utilization and increasing the heating capacity of the system.

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