Refrigerating and heating circulation system coupled with carbon dioxide energy storage

Abstract

The invention provides a refrigeration and heat supply circulation system coupled with carbon dioxide energy storage, and relates to the technical field of energy storage circulation, energy storage circulation is carried out based on conversion of a carbon dioxide critical state by taking carbon dioxide as a working medium, and cold and hot self-circulation in the refrigeration and heat supply circulation system is carried out through heat exchange. The cold and heat storage module is coupled to the carbon dioxide energy storage sub-module through the energy storage heat exchanger to conduct internal heat exchange of the refrigeration and heat supply circulation system, and heat exchange is conducted through the combination of the carbon dioxide energy storage sub-module and external energy. The refrigeration and heat supply module is coupled to the carbon dioxide sub energy storage module through the refrigeration and heat supply heat exchanger to conduct heat exchange between the refrigeration and heat supply circulation system and the outside, and the problems that an energy storage circulation system is low in energy utilization rate, large in environmental influence, low in system efficiency and unstable in energy utilization are solved. And the effects of improving the system efficiency, ensuring the stability of energy supply of the whole system and realizing zero carbonization of the technology are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage cycle, and in particular to a refrigeration and heating cycle system coupled with carbon dioxide energy storage. Background Art

[0002] With the changes in the global energy structure and the increase in environmental protection needs, the use of clean energy for efficient energy conversion and storage has become a hot topic in research and industry. In the field of energy conversion, especially in refrigeration and heating systems, traditional systems that rely on fossil fuels are gradually being replaced by systems driven by renewable energy. However, due to the high dependence and instability of renewable energy sources such as wind and solar energy, how to effectively store these energies and release them efficiently when needed has become a technical challenge. In addition, although current energy storage systems, such as pumped storage and compressed air energy storage, have shown potential in some commercial applications, they are often restricted by geographical location, and the equipment is large in size and low in energy density, making them unsuitable for widespread promotion. In addition, traditional refrigeration and heating systems often use working fluids such as Freon, which are not only harmful to the environment, but also aggravate global warming. Although some technologies have proposed the use of carbon dioxide as a working fluid for energy storage cycles, their technical directions are relatively scattered. At the same time, in existing refrigeration and heating technologies, the energy conversion efficiency is usually limited by the limitations of the working fluids used and the technology, and it is impossible to truly achieve storage and use integration, cooling and heating integration, resulting in high equipment investment costs and long payback periods, which is not conducive to the economic benefits and stable and continuous operation of the overall system.

[0003] In summary, existing energy storage cycle systems often have technical problems such as low energy utilization, large environmental impact, low system efficiency and unstable energy utilization, which in turn limits the wide application and economic benefits of the system. Summary of the invention

[0004] The present application provides a refrigeration and heating cycle system coupled with carbon dioxide energy storage, which is used to solve the technical problems of low energy utilization, large environmental impact, low system efficiency and unstable energy utilization in existing energy storage cycle systems, thereby limiting the wide application and economic benefits of the system.

[0005] The present application provides a refrigeration and heating cycle system coupled with carbon dioxide energy storage, the system comprising:

[0006] The carbon dioxide sub-energy storage module is used to use carbon dioxide as a working fluid and perform energy storage cycle based on the transition of the critical state of carbon dioxide; the cold and heat storage module is used to perform cold and heat self-circulation within the refrigeration and heating cycle system through heat exchange; the first coupling heat exchange module is used to couple the cold and heat storage module to the carbon dioxide sub-energy storage module through an energy storage heat exchanger to perform internal heat exchange of the refrigeration and heating cycle system; the refrigeration and heating module is used to combine the carbon dioxide sub-energy storage module to exchange heat with external energy; the second coupling heat exchange module is used to couple the refrigeration and heating module to the carbon dioxide sub-energy storage module through a refrigeration and heating heat exchanger to perform heat exchange between the refrigeration and heating cycle system and the outside.

[0007] The present application proposes a refrigeration and heating cycle system coupled with carbon dioxide energy storage, which uses carbon dioxide as a working fluid and performs energy storage cycle based on the transition of the critical state of carbon dioxide; performs cold and hot self-circulation inside the refrigeration and heating cycle system through heat exchange; couples the cold and heat storage module to the carbon dioxide sub-energy storage module through an energy storage heat exchanger to perform internal heat exchange in the refrigeration and heating cycle system; combines the carbon dioxide sub-energy storage module to exchange heat with external energy; couples the refrigeration and heating module to the carbon dioxide sub-energy storage module through a refrigeration and heating heat exchanger to perform heat exchange between the refrigeration and heating cycle system and the outside, thereby solving the technical problems of low energy utilization rate, large environmental impact, low system efficiency and unstable energy utilization in the existing energy storage cycle system, thereby limiting the wide application and economic benefits of the system. By using carbon dioxide as a working fluid, efficient storage and release of energy is achieved. At the same time, through the highly integrated optimization of the system, the operating cost is reduced and the environmental compatibility of the system is improved, and true zero-carbon emissions and efficient energy utilization are achieved, thereby greatly reducing the initial investment and redundancy of equipment, improving system efficiency, and ensuring the stability of the overall system energy supply and the technical effect of achieving zero carbonization. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 A schematic diagram of the structure of a refrigeration and heating cycle system coupled with carbon dioxide energy storage provided in an embodiment of the present application;

[0009] Figure 2 A schematic diagram of the energy flow structure of a refrigeration and heating cycle system coupled with carbon dioxide energy storage provided in an embodiment of the present application.

[0010] Explanation of the accompanying drawings: carbon dioxide sub-energy storage module 11, cold and heat storage module 12, first coupled heat exchange module 13, refrigeration and heating module 14, second coupled heat exchange module 15, third heat exchanger 10, fourth heat exchanger 20, first heat exchanger 30, second heat exchanger 40, hot water tank 50, cold water tank 60, low pressure tank 70, high pressure tank 80, energy storage compressor 90, heating compressor 100, refrigeration compressor 110, heating throttle valve 120, refrigeration throttle valve 130, condenser 140, evaporator 150, turbine machinery 160. DETAILED DESCRIPTION

[0011] In order to make the purpose, technical solutions and advantages of this application more clear, the following Figure 1 , 2 It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0012] The refrigeration and heating cycle system is a system that can provide both refrigeration and heating functions. This type of system mainly relies on thermodynamic cycles to transfer heat so that one environment can be cooled while the other is heated at the same time. The advantages of this system are high energy efficiency, multi-purpose (that is, the same system can be used for refrigeration and heating), and it is more environmentally friendly than traditional heating and cooling systems. Among the energy storage methods of the refrigeration and heating cycle system, the megawatt-level, long-term energy storage technologies that have been commercially applied are mainly pumped storage and compressed air energy storage. Carbon dioxide energy storage is a type of compressed air energy storage. The critical point of air is 3.77MPa and -140.5℃, while the critical point of carbon dioxide is only 7.39MPa and 31.4 degrees Celsius. It has more friendly critical conditions than air, and supercritical carbon dioxide has good thermophysical properties such as low viscosity and high density. Energy storage can be completed using a small and simple impeller machinery and heat transfer unit. At the same time, carbon dioxide has good thermal stability, non-toxicity, non-flammability, zero ozone depletion and other potential environmental protection characteristics, which makes it a reality to replace conventional refrigerants such as Freon and R134a. Therefore, since it is easier to achieve liquefaction than air, this application uses carbon dioxide as the working fluid for energy storage research. In addition, liquid carbon dioxide energy storage is not restricted by harsh geographical environments, and the main equipment is small in size and has a high energy storage density, which is suitable for large-scale commercial promotion on a large scale, and is more in line with the requirements of a zero-carbon technology system.

[0013] The present application embodiment provides a refrigeration and heating cycle system coupled with carbon dioxide energy storage, such as Figure 1 As shown, the system comprises:

[0014] The carbon dioxide sub-energy storage module 11 is used to use carbon dioxide as a working fluid and perform energy storage cycles based on the transition of the critical state of carbon dioxide.

[0015] The cold and heat storage module 12 is used for self-circulating cold and heat inside the refrigeration and heating cycle system through heat exchange.

[0016] The first coupling heat exchange module 13 is used to couple the cold and heat storage module to the carbon dioxide sub-energy storage module through an energy storage heat exchanger to perform internal heat exchange of the refrigeration and heating cycle system.

[0017] The cooling and heating module 14 is used to combine the carbon dioxide sub-energy storage module with external energy to exchange heat.

[0018] The second coupling heat exchange module 15 is used to couple the cooling and heating module to the carbon dioxide sub-energy storage module through a cooling and heating heat exchanger to perform heat exchange between the cooling and heating cycle system and the outside.

[0019] Furthermore, the cooling and heating heat exchanger includes a first heat exchanger 30 and a second heat exchanger 40 , and the energy storage heat exchanger includes a third heat exchanger 10 and a fourth heat exchanger 20 .

[0020] Specifically, the present application proposes a refrigeration and heating cycle system using carbon dioxide as a working fluid. The system realizes energy storage and release through efficient energy storage and heat exchange mechanisms, and meets the dual requirements of environmental protection and energy efficiency. The system mainly includes five core modules, namely, a carbon dioxide sub-energy storage module, a cold and heat storage module, a first coupled heat exchange module, a refrigeration and heating module, and a second coupled heat exchange module. Among them, the core function of the carbon dioxide sub-energy storage module is to use carbon dioxide as a working fluid to store and release energy through the change of its physical properties under the critical state. In this module, carbon dioxide crosses its critical point during the compression and expansion process to achieve high efficiency of energy conversion. The transition of this critical state allows carbon dioxide to store a large amount of energy with a small volume change, thereby improving the energy storage density and the overall energy efficiency of the system. The cold and heat storage module uses an energy storage heat exchanger to perform cold and hot self-circulation inside the system. In this process, the thermal energy of carbon dioxide is used for cooling or heating, depending on the operating mode of the system. The design of the cold and heat storage module enables the system to flexibly adjust the output of cold and heat in different seasons and environmental conditions, avoiding additional cold source and heat source replenishment, improving the system energy storage efficiency, increasing the overall economy, and meeting different user needs. The function of the first coupling heat exchange module is to couple the cold and heat storage module with the carbon dioxide sub-energy storage module through the energy storage heat exchanger, namely the third heat exchanger 10 and the fourth heat exchanger 20. In this step, the third heat exchanger 10 is responsible for providing the heat of the hot water flowing out of the hot water tank 50 to the carbon dioxide sub-energy storage module so that the low-temperature and low-pressure carbon dioxide gas released from the low-pressure tank 70 is heated. The heated carbon dioxide gas takes away the heat so that the hot water becomes cold water and flows to the cold water tank; and the role of the fourth heat exchanger 20 is opposite to that of the third heat exchanger 10, which is to take away the heat in the carbon dioxide sub-energy storage module. The cooling and heating module combines the carbon dioxide sub-energy storage module with external energy for heat exchange, which is realized by the first heat exchanger 30 and the second heat exchanger 40. In the heating mode, the first heat exchanger 30 cools down the high-temperature and high-pressure carbon dioxide gas in the carbon dioxide sub-energy storage module, releasing its high-temperature energy to achieve the purpose of heating; in the cooling mode, the second heat exchanger 40 is used to absorb external heat and provide it to the high-pressure and low-temperature carbon dioxide liquid in the carbon dioxide sub-energy storage module for heat exchange to achieve the purpose of cooling. The second coupling heat exchange module is responsible for further coupling the cooling and heating module with the carbon dioxide sub-energy storage module through the cooling and heating heat exchanger to optimize the heat exchange efficiency of the entire system. This design ensures that the system can operate efficiently and stably under different operating conditions, while minimizing the loss of heat and cold. Through the above steps, not only the energy utilization efficiency is significantly improved, but also an environmentally friendly cooling and heating solution is realized, meeting the needs of modern society for efficient and environmentally friendly energy systems.

[0021] Furthermore, the carbon dioxide sub-energy storage module 11 includes a low-pressure tank 70, a third heat exchanger 10, an energy storage compressor 90, a first heat exchanger 30, a high-pressure tank 80, a second heat exchanger 40, a turbine 160 and a fourth heat exchanger 20 connected in sequence, and the energy storage cycle process includes:

[0022] The low-temperature and low-pressure carbon dioxide gas released from the low-pressure tank 70 is heated by the third heat exchanger 10, and the heated medium-temperature and low-pressure carbon dioxide gas is pressurized by the energy storage compressor 90 to obtain high-temperature and high-pressure carbon dioxide gas.

[0023] The high-temperature and high-pressure carbon dioxide gas is cooled by the first heat exchanger 30, and the cooled high-pressure and low-temperature carbon dioxide liquid is stored in the high-pressure tank 80 to obtain storage energy.

[0024] The high-pressure and low-temperature carbon dioxide liquid flowing out of the high-pressure tank 80 is heated by the second heat exchanger 40 to obtain high-temperature and high-pressure carbon dioxide gas.

[0025] The high-temperature and high-pressure carbon dioxide gas entering the turbine machinery 160 drives the steam turbine to generate electricity, releases the stored energy, and obtains low-pressure and medium-temperature carbon dioxide gas.

[0026] The low-pressure and medium-temperature carbon dioxide gas is cooled by the fourth heat exchanger 20 to obtain low-temperature and low-pressure carbon dioxide gas, which is then stored in the low-pressure tank 70 .

[0027] Optionally, the carbon dioxide sub-energy storage module includes a low-pressure tank 70, a third heat exchanger 10, an energy storage compressor 90, a first heat exchanger 30, a high-pressure tank 80, a second heat exchanger 40, a turbine 160 and a fourth heat exchanger 20 connected in sequence. The specific energy storage cycle process is that the low-temperature and low-pressure carbon dioxide gas released from the low-pressure tank 70 is first sent to the third heat exchanger 10. In this heat exchanger, the carbon dioxide gas is heated to medium temperature by hot water sent from the hot water tank 50. The heated medium-temperature and low-pressure carbon dioxide gas is then sent to the energy storage compressor 90, where the gas is compressed, and the temperature and pressure are significantly increased, and it is transformed into a high-temperature and high-pressure state. The high-temperature and high-pressure carbon dioxide gas processed by the compressor then flows into the first heat exchanger 30. In the first heat exchanger 30, the high-temperature gas is cooled and condensed into a liquid state. The heat released in this process can be discharged to the outside by the system, that is, to provide heat for the heating unit. The cooled high-pressure and low-temperature carbon dioxide liquid is stored in the high-pressure tank 80, and the energy is stored in the form of compressed liquid. When the system needs to release energy, the low-temperature and high-pressure carbon dioxide liquid stored in the high-pressure tank 80 will be sent to the second heat exchanger 40, where it will be heated again and converted back to a high-temperature and high-pressure gas state, wherein the heating and heating process is carried out by absorbing external heat through the refrigeration unit. Subsequently, this high-temperature and high-pressure gas enters the turbine machinery 160 to drive the steam turbine to generate electricity, thereby effectively releasing the stored energy. The mechanical energy generated by the rotation of the turbine machinery 160 can be converted into electrical energy and supplied to the system or the external power grid. Finally, the low-pressure and medium-temperature carbon dioxide gas after energy release flows into the fourth heat exchanger 20, where it is further cooled to a low-temperature and low-pressure state by heat exchange with the cold water flowing out of the cold water tank 60, completing the energy release cycle. The cooled gas is stored back in the low-pressure tank 70 to prepare for the next round of energy storage cycle. This coherent process not only ensures the efficient use of energy, but also minimizes the loss of energy during the conversion process, thereby improving the economy and environmental protection of the overall system.

[0028] Furthermore, the cold and heat storage module 12 includes a hot water tank 50, a third heat exchanger 10, a cold water tank 60 and a fourth heat exchanger 20 connected in sequence, and the cold and hot self-circulation process includes:

[0029] The cold water flowing out of the cold water tank 60 absorbs heat and is heated by the fourth heat exchanger 20 to obtain heated hot water, which is then stored in the hot water tank 50 .

[0030] The hot water flowing out of the hot water tank 50 is cooled by the third heat exchanger 10 to obtain cooled cold water, which is then returned to the cold water tank 60 .

[0031] Exemplarily, the cold and heat storage module is designed to realize the cold and heat self-circulation in the refrigeration and heating cycle system, thereby improving the energy efficiency of the system and the economy of operation. The module is composed of a hot water tank 50, a third heat exchanger 10, a cold water tank 60 and a fourth heat exchanger 20 connected in sequence. It specifically includes a cold water heating process and a hot water cooling process. In the cold water heating process, in the initial stage, cold water flows out of the cold water tank 60 and enters the fourth heat exchanger 20. In the fourth heat exchanger 20, the cold water absorbs heat and the temperature gradually increases. In this process, the design of the heat exchanger ensures the efficient transfer of heat energy, so that the cold water is effectively converted into hot water. The heated hot water is then sent to the hot water tank 50 for storage, ready for the next step of heat energy use or further energy conversion. In the hot water cooling process, hot water flows out of the hot water tank 50 and enters the third heat exchanger 10. In this heat exchanger, the hot water releases heat, causing the water temperature to drop. The function of the third heat exchanger is to use its efficient heat exchange capacity to transfer the heat energy in the hot water, thereby reducing the water temperature and converting it into cold water. This step can flexibly replenish the energy in the carbon dioxide sub-energy storage module. Through the above-mentioned cold and hot self-circulation process, the cold and heat storage module effectively manages the flow of thermal energy in the system, enabling the system to maintain efficient energy utilization when switching between cooling and heating modes. At the same time, the design of this module takes into account the maximum recovery and recycling of energy, ensuring that the system can achieve continuous and stable operation without increasing additional energy consumption. Therefore, the cold and heat storage module not only improves the efficiency of energy use, but also meets the environmental protection requirements of energy conservation and emission reduction, and is suitable for modern refrigeration and heating systems that require efficient energy management.

[0032] Further, the cooling and heating module 14 includes a heating unit and a cooling unit, wherein the heating unit includes a heating compressor 100, a condenser 140, a heating throttle valve 120 and a first heat exchanger 30 connected in sequence, and the heat exchange process in the heat exchange with external energy includes:

[0033] The heating compressor 100 pressurizes and raises the temperature of carbon dioxide gas at normal temperature and pressure to obtain high-temperature and high-pressure carbon dioxide gas.

[0034] The high-temperature and high-pressure carbon dioxide gas is sent to the condenser 140 to release heat and heat up to obtain high-pressure and low-temperature carbon dioxide liquid, and the high-pressure and low-temperature carbon dioxide is reduced in pressure and cooled by the heating throttle valve 120, and combined with the first heat exchanger 30 to absorb heat and heat up to obtain carbon dioxide gas at normal temperature and pressure.

[0035] The carbon dioxide gas at normal temperature and pressure is continuously fed into the heating compressor 100 .

[0036] Further, the refrigeration and heating module is mainly composed of a heating unit and a refrigeration unit, wherein the heating unit includes a heating compressor 100, a condenser 140, a heating throttle valve 120 and a first heat exchanger 30 connected in sequence. Specifically, the operation of the heating unit starts with the heating compressor 100, which compresses and heats the carbon dioxide gas at normal temperature and pressure. Through this process, the temperature and pressure of the carbon dioxide gas increase significantly and change to a high temperature and high pressure state. This step is the key to the energy conversion process because it provides the necessary thermal energy basis for subsequent heat exchange. Next, the high temperature and high pressure carbon dioxide gas is sent to the condenser 140. In the condenser 140, the carbon dioxide gas releases heat to the outside, and the temperature of the carbon dioxide decreases during this heat release process, and a phase change occurs at the same time, from a gaseous state to a liquid state. The heat released in this process can be used for building heating or other thermal energy needs, realizing a useful conversion of energy. The high-pressure and low-temperature carbon dioxide liquid treated by the condenser 140 enters the heating throttle valve 120, at which time the throttle valve is decompressed and cooled, and the carbon dioxide is further cooled and ready to enter the first heat exchanger 30. In the first heat exchanger 30, the carbon dioxide liquid absorbs the heat inside the carbon dioxide sub-energy storage module, heats up and re-gasifies into carbon dioxide gas at normal temperature and pressure. This step not only recovers the residual heat energy in the system, but also provides conditions for the re-compression and circulation of the carbon dioxide gas. Subsequently, the heated carbon dioxide gas at normal temperature and pressure is sent to the heating compressor 100 again, and a new round of energy compression and heating process is restarted, forming a closed-loop cycle to ensure the continuous utilization and conversion efficiency of energy. Through the above process, the heating unit can efficiently recover and recycle heat energy, optimize the overall energy utilization efficiency, and reduce environmental impact. In addition, the system design takes into account the continuity and stability of energy conversion, ensuring that the heating unit can operate stably under various operating conditions and meet diverse thermal energy needs.

[0037] Further, the refrigeration unit includes a refrigeration compressor 110, a second heat exchanger 40, a refrigeration throttle valve 130 and an evaporator 150 connected in sequence, and the refrigeration exchange process in the heat exchange with external energy includes:

[0038] The carbon dioxide gas at normal temperature and pressure is compressed by the refrigeration compressor 110 to obtain high-temperature and high-pressure carbon dioxide gas.

[0039] The high-temperature and high-pressure carbon dioxide gas is subjected to heat release and temperature reduction in the second heat exchanger 40 to obtain high-pressure and low-temperature carbon dioxide liquid.

[0040] The high-pressure and low-temperature carbon dioxide is decompressed and cooled by the refrigeration throttle valve 130 , and the evaporator 150 is used to absorb heat and cool the outside to obtain carbon dioxide gas at normal temperature and pressure, which is continuously fed into the refrigeration compressor 110 .

[0041] Specifically, the refrigeration unit is used to effectively perform a refrigeration cycle to achieve cooling and heat management of the environment. The refrigeration unit includes a refrigeration compressor 110, a second heat exchanger 40, a refrigeration throttle valve 130 and an evaporator 150 connected in sequence. Specifically, the first link of the refrigeration cycle is the refrigeration compressor 110, in which carbon dioxide gas at normal temperature and pressure is compressed. In this process, the pressure and temperature of the carbon dioxide gas increase significantly and turn into a high temperature and high pressure state. This step is the power source of the entire refrigeration cycle, providing the necessary high energy state gas for subsequent heat energy transfer and cooling. After that, the high temperature and high pressure carbon dioxide gas then flows into the second heat exchanger 40. Here, carbon dioxide releases heat and achieves temperature reduction through heat exchange with the carbon dioxide sub-energy storage module. In this process, carbon dioxide changes from gas to liquid and becomes high pressure and low temperature carbon dioxide liquid. The key to the design of the second heat exchanger 40 is the high efficiency heat exchange capacity to ensure that heat can be quickly and effectively removed from carbon dioxide. The cooled and condensed carbon dioxide liquid is then decompressed by the refrigeration throttle valve 130, so that the carbon dioxide liquid evaporates rapidly while the pressure is reduced, and the temperature is further reduced. The function of the refrigeration throttle valve 130 is to control the flow rate and pressure of carbon dioxide and optimize the thermodynamic efficiency of the evaporation process. In the evaporator 150, the decompressed carbon dioxide evaporates by absorbing heat from the environment, and the cold effect generated by this process is used to cool the environment or provide services for other refrigeration needs. While the carbon dioxide gas absorbs heat, the ambient heat is effectively reduced to achieve the purpose of refrigeration. Finally, the evaporated carbon dioxide gas at normal temperature and pressure is circulated back to the refrigeration compressor 110 to restart a new round of compression and circulation process. Through the above-mentioned continuous refrigeration process, the refrigeration unit not only achieves efficient heat extraction and environmental cooling, but also maximizes energy utilization and system economy through closed-loop circulation design. In addition, the system ensures the stability and continuity of the refrigeration effect by precisely controlling the operation and interaction of each component, and is suitable for various application scenarios requiring efficient refrigeration.

[0042] Furthermore, the heat exchange process of the first coupling heat exchange module 13 includes:

[0043] Based on the third heat exchanger 10 , the low-temperature and low-pressure carbon dioxide gas delivered from the low-pressure tank 70 is heated by the hot water delivered from the hot water tank 50 .

[0044] Based on the fourth heat exchanger 20 , the low-pressure and medium-temperature carbon dioxide gas after energy release is cooled down by the cold water delivered from the cold water tank 60 .

[0045] Optionally, the first coupled heat exchange module is a high-efficiency heat exchange system, which aims to achieve temperature regulation and energy recycling of carbon dioxide gas by optimizing thermal energy management. The core of the design of this module is to use the temperature difference between hot water and cold water to heat and cool carbon dioxide gas through the third heat exchanger 10 and the fourth heat exchanger 20, thereby improving the energy efficiency and performance of the overall system. In the early stage of the operation of the first coupled heat exchange module, hot water is transported from the hot water tank 50 to the third heat exchanger 10. At this time, the third heat exchanger 10 acts as an intermediary for heat energy transfer, and uses the heat energy stored in the hot water to heat the low-temperature and low-pressure carbon dioxide gas transported from the low-pressure tank 70. In this process, the carbon dioxide gas absorbs heat from the hot water, causing its temperature to rise, thereby increasing the gas energy, providing the necessary conditions for subsequent energy conversion and utilization. At the same time, the fourth heat exchanger 20 undertakes the task of cooling. At this stage, the cold water transported from the cold water tank 60 is introduced into the fourth heat exchanger 20. When the low-pressure medium-temperature carbon dioxide gas after energy release flows through the fourth heat exchanger 20, the cold water it encounters absorbs the heat stored in the gas, causing the temperature of the carbon dioxide to drop. This cooling process not only helps stabilize the temperature of the system, but also provides a low-temperature environment for the recycling of carbon dioxide. By heating the carbon dioxide gas with hot water and cooling it with cold water, the temperature of the gas is efficiently adjusted, and the energy utilization efficiency is also optimized. Through such a design, the first coupled heat exchange module not only realizes the efficient recovery and reuse of energy, but also ensures the energy demand and environmental adaptability of the entire system at different working stages, thereby significantly improving the overall performance and economic benefits of the system.

[0046] Furthermore, the heat exchange process of the second coupling heat exchange module 15 includes:

[0047] Based on the first heat exchanger 30 , the high-temperature and high-pressure carbon dioxide gas coming out of the energy storage compressor 90 is cooled by the carbon dioxide whose pressure and temperature are reduced by the heating throttle valve 120 .

[0048] Based on the second heat exchanger 40 , the high-pressure and high-temperature carbon dioxide gas pressurized and heated by the refrigeration compressor 110 heats and heats the high-pressure and low-temperature carbon dioxide liquid coming out of the high-pressure tank 80 .

[0049] Furthermore, the second coupled heat exchange module includes two core heat exchange processes, namely, a cooling process based on the first heat exchanger 30 and a heating process based on the second heat exchanger 40, which aims to optimize the performance of the entire refrigeration and heating system. In the cooling process based on the first heat exchanger 30, the carbon dioxide gas after decompression and cooling is reduced by the heating throttle valve 120. This part of the gas has been reduced in temperature and pressure by decompression in the previous heating cycle. These low-temperature carbon dioxide gases then flow to the first heat exchanger 30 to cool the high-temperature and high-pressure carbon dioxide gas coming out of the energy storage compressor 90. This high-temperature and high-pressure gas contains a large amount of thermal energy. Through heat exchange with the low-temperature gas, heat release and temperature reduction are achieved, which optimizes energy management and reduces heat loss of the system. In the heating process based on the second heat exchanger 40, the high-pressure and high-temperature carbon dioxide gas generated by the pressurization and temperature increase of the refrigeration compressor 110 is used to heat the high-pressure and low-temperature carbon dioxide liquid stored in the high-pressure tank 80. The key to this step is to use the heat energy generated from the refrigeration unit and transfer it to the low-temperature carbon dioxide liquid through the second heat exchanger 40 to increase its temperature and potentially re-gasify it, thereby preparing for the next energy release process. The effective combination of these two heat exchange processes ensures the optimal performance of the system in terms of thermal energy management, so that heat energy can be recovered and reused to the maximum extent in the system, rather than simply lost or consumed. In this way, the second coupled heat exchange module not only improves the efficiency of energy use, but also reduces the environmental impact of the energy conversion process. Overall, the module significantly improves the overall energy efficiency and reliability of the cooling and heating system through meticulous and precise temperature and pressure control.

[0050] Furthermore, the turbine machinery 160 is connected to the heating compressor 100 and the refrigeration compressor 110 respectively, so as to provide power supply to the heating compressor 100 and the refrigeration compressor 110 .

[0051] Specifically, the turbine machinery 160 (i.e., turbine) is used to effectively connect and provide power support to the heating compressor 100 and the refrigeration compressor 110 in the system. The main function of the turbine machinery 160 is to convert the kinetic energy of the high-pressure and high-temperature carbon dioxide gas into mechanical energy, and further into electrical energy. In this system, the turbine machinery 160 is used to receive the energy-releasing gas from the energy storage subsystem. These high-temperature and high-pressure carbon dioxide gases drive the turbine to rotate, and the generated mechanical energy is converted into electricity through the generator. The electricity generated is not directly supplied to the external power grid, but is preferentially used to drive the heating compressor 100 and the refrigeration compressor 110 in the system. This internal power recycling significantly improves energy efficiency and reduces dependence on external power resources. The compressor is directly supported by the internally generated electricity, maintaining a high degree of energy self-sufficiency and operating efficiency. At the same time, by directly connecting the turbine machinery 160 to the heating and refrigeration compressors, the energy conversion process of the system is more compact and efficient. This design not only optimizes energy flow and reduces energy loss, but also adjusts the working efficiency of the compressor by precisely controlling the output of the turbine machinery to ensure that the best energy efficiency ratio can be achieved under different working conditions. By using the turbomachine 160 as a power source connected to the heating and cooling compressors, a closed-loop energy management system is effectively implemented, which not only improves energy efficiency but also enhances the environmental sustainability of the system.

[0052] Based on the technical solutions of the above embodiments, the refrigeration and heating cycle system coupled with carbon dioxide energy storage provided by the present application has the following technical effects:

[0053] 1. Improve the system energy storage efficiency: The carbon dioxide sub-storage module is combined with the cold and heat storage module through the energy storage heat exchanger to realize the system's cold and hot self-circulation, avoid additional cold and heat source replenishment, improve the system's energy storage efficiency, and increase overall economy.

[0054] 2. Achieve true zero-carbonization of energy storage, cooling and heating: By connecting to external renewable resources such as wind and solar power, the carbon dioxide sub-energy storage module realizes the use of green electricity. When the user has heating and cooling needs, the green electricity is released through the energy storage system as power for cooling and heating.

[0055] 3. Reconstruction of green energy supply mode: The working fluid for cooling and heating is carbon dioxide, which abandons the traditional fossil energy supply methods such as chlorofluorocarbons and coal-fired boilers.

[0056] 4. Green and stable operation of the cooling and heating systems: The power supply for the cooling and heating systems comes from the energy release process of the energy storage system, which not only avoids the instability of heating and cooling caused by direct external green electricity, but also avoids the increase in costs caused by grid electricity consumption.

[0057] 5. Since carbon dioxide is used as the working fluid, the refrigeration and heating equipment is compact as a whole, and can better ensure heating efficiency in extreme weather conditions compared to air source heat pumps. At the same time, each module has a simple structure and high integration, and can be quickly applied on a large scale.

[0058] In summary, the refrigeration and heating cycle system coupled with carbon dioxide energy storage provided in the present application not only improves the overall efficiency of the carbon dioxide energy storage system, but also realizes green, zero-carbon, stable, low-cost and high-efficiency refrigeration and heating, effectively addresses a series of problems existing in existing cold and heat storage technologies, and realizes efficient storage and release of energy. At the same time, through highly integrated optimization of the system, it reduces operating costs and improves the environmental compatibility of the system.

[0059] The above specific implementation manner does not constitute a limitation to the protection scope of the present application. It should be understood by those skilled in the art that various modifications, combinations and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application. In some cases, the actions or steps recorded in the present application can be performed in an order different from that in the embodiment and can still achieve the desired results. In addition, the process depicted in the accompanying drawings does not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

Claims

1. A refrigeration and heating cycle system coupled with carbon dioxide energy storage, characterized in that: The system comprises: The carbon dioxide sub-energy storage module is used to use carbon dioxide as a working fluid and perform energy storage cycles based on the transition of the critical state of carbon dioxide; The cold and heat storage module is used to carry out the cold and heat self-circulation inside the refrigeration and heating cycle system through heat exchange; A first coupling heat exchange module is used to couple the cold and heat storage module to the carbon dioxide sub-energy storage module through an energy storage heat exchanger to perform internal heat exchange in a refrigeration and heating cycle system; A cooling and heating module, used for exchanging heat with external energy in combination with the carbon dioxide sub-energy storage module; The second coupling heat exchange module is used to couple the refrigeration and heating module to the carbon dioxide sub-energy storage module through a refrigeration and heating heat exchanger to perform heat exchange between the refrigeration and heating cycle system and the outside.

2. A refrigeration and heating cycle system coupled with carbon dioxide energy storage as claimed in claim 1, characterized in that: The cooling and heating heat exchanger comprises a first heat exchanger (30) and a second heat exchanger (40), and the energy storage heat exchanger comprises a third heat exchanger (10) and a fourth heat exchanger (20).

3. A refrigeration and heating cycle system coupled with carbon dioxide energy storage as claimed in claim 2, characterized in that: The carbon dioxide sub-energy storage module comprises a low-pressure tank (70), a third heat exchanger (10), an energy storage compressor (90), a first heat exchanger (30), a high-pressure tank (80), a second heat exchanger (40), a turbine (160) and a fourth heat exchanger (20) which are connected in sequence. The energy storage cycle process comprises: The low-temperature and low-pressure carbon dioxide gas released from the low-pressure tank (70) is heated by the third heat exchanger (10), and the heated medium-temperature and low-pressure carbon dioxide gas is pressurized by the energy storage compressor (90) to obtain high-temperature and high-pressure carbon dioxide gas; The high-temperature and high-pressure carbon dioxide gas is cooled by a first heat exchanger (30), and the cooled high-pressure and low-temperature carbon dioxide liquid is stored in a high-pressure tank (80) to obtain storage energy; The high-pressure and low-temperature carbon dioxide liquid flowing out of the high-pressure tank (80) is heated by a second heat exchanger (40) to obtain high-temperature and high-pressure carbon dioxide gas; The high-temperature and high-pressure carbon dioxide gas entering the turbine machinery (160) drives a steam turbine to generate electricity, releases the stored energy, and obtains low-pressure and medium-temperature carbon dioxide gas; The low-pressure and medium-temperature carbon dioxide gas is cooled by the fourth heat exchanger (20) to obtain low-temperature and low-pressure carbon dioxide gas, which is then stored in the low-pressure tank (70).

4. A refrigeration and heating cycle system coupled with carbon dioxide energy storage as claimed in claim 3, characterized in that: The cold and heat storage module comprises a hot water tank (50), a third heat exchanger (10), a cold water tank (60) and a fourth heat exchanger (20) which are connected in sequence, and the cold and heat self-circulation process comprises: The cold water flowing out of the cold water tank (60) is subjected to heat absorption and temperature raising by the fourth heat exchanger (20) to obtain heated hot water, which is then stored in the hot water tank (50); The hot water flowing out of the hot water tank (50) is cooled by releasing heat through the third heat exchanger (10) to obtain cooled cold water, which is then returned to the cold water tank (60).

5. A refrigeration and heating cycle system coupled with carbon dioxide energy storage as claimed in claim 4, characterized in that: The cooling and heating module comprises a heating unit and a cooling unit, wherein the heating unit comprises a heating compressor (100), a condenser (140), a heating throttle valve (120) and a first heat exchanger (30) connected in sequence, and the heat exchange process in the heat exchange with external energy comprises: The carbon dioxide gas at normal temperature and pressure is pressurized and heated by a heating compressor (100) to obtain high-temperature and high-pressure carbon dioxide gas; The high-temperature and high-pressure carbon dioxide gas is sent to a condenser (140) to release heat and increase temperature to obtain high-pressure and low-temperature carbon dioxide liquid, and the high-pressure and low-temperature carbon dioxide is decompressed and cooled by a heating throttle valve (120), and combined with a first heat exchanger (30) to absorb heat and increase temperature to obtain carbon dioxide gas at normal temperature and pressure; The carbon dioxide gas at normal temperature and pressure is continuously fed into the heating compressor (100).

6. A refrigeration and heating cycle system coupled with carbon dioxide energy storage as claimed in claim 5, characterized in that: The refrigeration unit comprises a refrigeration compressor (110), a second heat exchanger (40), a refrigeration throttle valve (130) and an evaporator (150) which are connected in sequence, and the refrigeration exchange process in the heat exchange with external energy comprises: Compressing carbon dioxide gas at normal temperature and pressure by means of a refrigeration compressor (110) to obtain high-temperature and high-pressure carbon dioxide gas; In a second heat exchanger (40), the high-temperature and high-pressure carbon dioxide gas is subjected to heat release and temperature reduction to obtain a high-pressure and low-temperature carbon dioxide liquid; The high-pressure and low-temperature carbon dioxide is decompressed and cooled by a refrigeration throttle valve (130), and external heat absorption and refrigeration are performed based on an evaporator (150) to obtain carbon dioxide gas at normal temperature and pressure, which is continuously fed into the refrigeration compressor (110).

7. A refrigeration and heating cycle system coupled with carbon dioxide energy storage as claimed in claim 4, characterized in that: The heat exchange process of the first coupled heat exchange module includes: Based on the third heat exchanger (10), the low-temperature and low-pressure carbon dioxide gas delivered from the low-pressure tank (70) is heated by the hot water delivered from the hot water tank (50); Based on the fourth heat exchanger (20), the low-pressure medium-temperature carbon dioxide gas after energy release is cooled down by the cold water delivered from the cold water tank (60).

8. A refrigeration and heating cycle system coupled with carbon dioxide energy storage as claimed in claim 6, characterized in that: The heat exchange process of the second coupled heat exchange module includes: Based on the first heat exchanger (30), the carbon dioxide after decompression and temperature reduction through the heating throttle valve (120) is used to cool down the high-temperature and high-pressure carbon dioxide gas coming out of the energy storage compressor (90); Based on the second heat exchanger (40), the high-pressure and high-temperature carbon dioxide gas pressurized and heated by the refrigeration compressor (110) heats and raises the temperature of the high-pressure and low-temperature carbon dioxide liquid coming out of the high-pressure tank (80).

9. A refrigeration and heating cycle system coupled with carbon dioxide energy storage as claimed in claim 6, characterized in that: The turbine machine (160) is connected to the heating compressor (100) and the refrigeration compressor (110) respectively, and is used to provide power supply to the heating compressor (100) and the refrigeration compressor (110).

Images