A combined heat and pressure potential energy storage cogeneration system and method

Abstract

The application discloses a kind of heat energy and pressure potential energy combined energy storage heat and power cogeneration system and method, it is stored up to compress low-temperature low-pressure carbon dioxide into high-temperature high-pressure supercritical state when energy storage, simultaneously, part heat energy released in compression is stored in high-temperature heat storage material.Electricity generation uses the pressure potential energy of supercritical carbon dioxide to drive expander to work and generate electricity when electricity generation, and the condensed carbon dioxide after expansion enters low-pressure storage heat exchanger, and the heat energy released is stored in low-temperature heat storage material.Carbon dioxide absorbs the heat energy in high-temperature heat storage material when expansion, so that heat energy is converted into pressure potential energy, and then converted into mechanical energy and electric energy.Energy storage process initial stage, low-temperature heat storage material can also be directly transferred to high-temperature heat storage material by using heat pump to store heat energy.The system can also supply heat to the outside, and can realize heat and power cogeneration.

Description

Technical Field

[0001] This invention belongs to the field of energy storage technology, specifically relating to a combined thermal energy and pressure potential energy storage cogeneration system and method. Background Technology

[0002] To achieve the goals of carbon peaking and carbon neutrality, it is necessary to vigorously develop renewable energy power generation such as wind and solar power. However, renewable energy is characterized by instability and intermittency, and must be combined with energy storage to form a stable energy supply. However, existing energy storage technologies all have various drawbacks. For example, electrochemical energy storage technology has safety issues, is limited by resource conditions, requires the use of natural resources for raw materials, is non-renewable, cannot be sustainably developed indefinitely, and will also impose a burden on the environment.

[0003] Pumped storage technology requires special geographical conditions to build reservoirs and dams, making site selection difficult, and the construction period is long and the investment is large.

[0004] Existing compressed air energy storage and compressed carbon dioxide energy storage technologies suffer from large heat losses, low energy conversion efficiency, and require artificially synthesized working fluids, which can cause various environmental problems and burdens.

[0005] In view of the above factors, a combined thermal energy and pressure potential energy storage cogeneration system and method is specially designed. The system uses a heat pump to directly transfer the thermal energy in the low-temperature thermal storage material to the high-temperature thermal storage material for storage, which can provide heat to the outside and realize cogeneration. Summary of the Invention

[0006] The purpose of this invention is to provide a combined thermal energy and pressure potential energy storage system and method for cogeneration, in order to solve the problems mentioned in the background art.

[0007] The objective of this invention is achieved through the following technical solution: a combined thermal energy and pressure potential energy storage cogeneration system, comprising an expander, wherein the inlet of the expander is connected to a high-pressure carbon dioxide storage heat exchanger via a valve, the outlet of the high-pressure carbon dioxide storage heat exchanger is connected to a low-pressure carbon dioxide storage heat exchanger via a valve, the inlet of the high-pressure carbon dioxide storage heat exchanger is connected to a carbon dioxide compressor via a valve, and the outlet is connected to the expander via a valve; the inlet of the low-pressure carbon dioxide storage heat exchanger is connected to the expander via a valve, and the outlet is connected to the carbon dioxide compressor via a valve; the inlet of the carbon dioxide compressor is connected to the low-pressure carbon dioxide storage heat exchanger via a valve, and the outlet is connected to the high-pressure carbon dioxide storage heat exchanger via a valve.

[0008] The low-temperature thermal storage tank is filled with low-temperature thermal storage material. It is equipped with a low-pressure carbon dioxide storage heat exchanger and a heat pump evaporator, which exchange heat with the low-temperature thermal storage material.

[0009] The high-temperature heat storage tank is filled with high-temperature heat storage material. It is equipped with a high-pressure carbon dioxide storage heat exchanger, a heat pump energy storage heat exchanger, and a high-temperature heating heat exchanger, which exchange heat with the high-temperature heat storage material.

[0010] Low-temperature thermal energy storage materials are filled into low-temperature thermal energy storage tanks to store low-temperature thermal energy and exchange heat with low-pressure carbon dioxide storage heat exchangers and heat pump evaporators. High-temperature thermal energy storage materials are filled into low-temperature thermal energy storage tanks to store high-temperature thermal energy and exchange heat with high-pressure carbon dioxide storage heat exchangers, heat pump energy storage heat exchangers, and high-temperature heating heat exchangers.

[0011] Furthermore, the inlet of the heat pump evaporator is connected to the cooler and the expansion valve respectively, and its outlet is connected to the heat pump compressor and the heat pump heating heat exchanger respectively, and the heat pump working fluid exchanges heat with the low temperature heat storage material.

[0012] Furthermore, the inlet of the heat pump energy storage heat exchanger is connected to the heat pump compressor, the working fluid pump, and the cooler, respectively, and its outlet is connected to the heat pump expansion valve, through which the heat pump working fluid exchanges heat with the high-temperature heat storage material.

[0013] Furthermore, the inlet of the heat pump expansion valve is connected to the heat pump energy storage heat exchanger and the heat pump heating heat exchanger, respectively, and its outlet is connected to the heat pump evaporator and cooler.

[0014] Furthermore, the inlet of the heat pump compressor is connected to the heat pump evaporator and cooler, and its outlet is connected to the heat pump energy storage heat exchanger and the heat pump heating heat exchanger.

[0015] Furthermore, the working fluid pump inlet is connected to the heat pump evaporator, and its outlet is connected to the cooler, which causes the heat pump working fluid to circulate between the heat pump evaporator and the cooler.

[0016] The cooler inlet is connected to the heat pump evaporator and the expansion valve, respectively, and its outlet is connected to the heat pump evaporator and the heat pump compressor. The heat pump working fluid can exchange heat with cold and heat sources outside the system through it.

[0017] Furthermore, the low-temperature thermal storage material includes water, an ice-water mixture, an aqueous solution containing antifreeze, or a phase change thermal storage material;

[0018] High-temperature thermal storage materials include high-temperature and high-pressure water, aqueous solutions, salts, or phase change thermal storage materials.

[0019] A method for realizing a combined thermal energy and pressure potential energy storage cogeneration system includes a main energy storage process, a power generation process, an auxiliary energy storage process, a heat dissipation process, and a heat supply process.

[0020] The main energy storage process is an adiabatic compression process: the low-temperature, low-pressure carbon dioxide in the low-pressure carbon dioxide storage heat exchanger is compressed by the compressor into a high-temperature, high-pressure supercritical state and stored in the high-pressure carbon dioxide storage heat exchanger. At the same time, the carbon dioxide in the low-pressure carbon dioxide storage heat exchanger absorbs heat from the low-temperature heat storage material placed in the low-temperature heat storage tank. On the other hand, after the compressed carbon dioxide enters the high-pressure carbon dioxide storage heat exchanger, it releases some heat. This heat is stored in the high-temperature heat storage material placed in the high-temperature heat storage tank. During this process, the electrical energy that drives the compressor is stored as the pressure potential energy of the supercritical carbon dioxide and the thermal energy of the high-temperature heat storage material.

[0021] The power generation process is an adiabatic expansion process: supercritical carbon dioxide in the high-pressure carbon dioxide storage heat exchanger drives the expander to do work and then enters the low-pressure carbon dioxide storage heat exchanger. At the same time, the carbon dioxide in the high-pressure carbon dioxide storage heat exchanger absorbs heat from the high-temperature heat storage material, and the heat energy in the high-temperature heat storage material is transferred to the carbon dioxide in the high-pressure carbon dioxide storage heat exchanger and converted into pressure potential energy. On the other hand, after the expanded carbon dioxide enters the low-pressure carbon dioxide storage heat exchanger, it condenses and releases heat, and exchanges heat with the low-temperature heat storage material in the low-temperature heat storage tank. The heat energy is stored in the low-temperature heat storage material in the low-temperature heat storage tank. This process converts the pressure potential energy of carbon dioxide and the heat energy in the high-temperature heat storage material into mechanical energy to drive the expander, and then into electrical energy.

[0022] The auxiliary energy storage process is a Carnot cycle process: when power generation ends, the temperature of the high-temperature thermal storage material decreases. In the early stage of energy storage, before its temperature rises to a certain level, the heat in the low-temperature thermal storage material is transferred to the high-temperature thermal storage material by a heat pump. The electrical energy driving the heat pump compressor and part of the thermal energy in the low-temperature thermal storage material are stored in the high-temperature thermal storage material in the form of high-temperature thermal energy.

[0023] The heat dissipation process is a heat exchange process: when the above system dissipates heat, the heat pump working fluid absorbs heat from the low-temperature heat storage material in the heat pump evaporator, and then the working fluid is pumped into the cooler for cooling. Excess heat is carried away by the external cold source of the system.

[0024] The heating process is a heat exchange process: the return water is heated by the heat pump heat exchanger, which is another condenser of the heat pump, and the heat energy obtained comes from the heat pump system.

[0025] Furthermore, the specific process of auxiliary energy storage is as follows: the working fluid absorbs the low-temperature heat energy in the low-temperature heat storage material in the heat pump evaporator, and after evaporation, it is compressed by the heat pump compressor and enters the heat pump energy storage heat exchanger, where the heat is transferred to the high-temperature heat storage material and stored.

[0026] Furthermore, during operation, the heat pump system uses a heat pump evaporator as the evaporator to obtain a low-temperature heat source from the low-temperature heat storage material, or uses the aforementioned cooler as the evaporator to obtain a low-temperature heat source from an external heat source.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0028] In operation, the heat pump system of this invention can use a heat pump evaporator as the evaporator to obtain a low-temperature heat source from a low-temperature thermal storage material, or it can use the aforementioned cooler as the evaporator to obtain a low-temperature heat source from an external heat source. If the return water can reach the required temperature after being heated by the heat pump system, it is directly supplied with heat. If it cannot reach the required temperature, it enters a high-temperature heat exchanger for heating, obtaining heat from the high-temperature thermal storage material and raising its temperature before being supplied with heat.

[0029] This invention stores energy by compressing low-temperature, low-pressure carbon dioxide into a high-temperature, high-pressure supercritical state, while simultaneously storing some of the heat energy released during compression in a high-temperature thermal storage material. During power generation, the pressure potential energy of the supercritical carbon dioxide drives an expander to generate electricity. The expanded carbon dioxide then enters a low-pressure storage heat exchanger and condenses, releasing heat energy stored in the low-temperature thermal storage material. As the carbon dioxide expands, it absorbs heat energy from the high-temperature thermal storage material, converting the heat energy into pressure potential energy, which in turn is converted into mechanical and electrical energy. In the initial stage of the energy storage process, a heat pump can be used to directly transfer heat energy from the low-temperature thermal storage material to the high-temperature thermal storage material. The system can also supply heat externally, enabling combined heat and power (CHP).

[0030] This invention relates to a system and method for combined thermal and pressure potential energy storage and cogeneration using transcritical carbon dioxide cycle. This not only improves energy conversion efficiency, but also uses natural working fluids, eliminating the need for artificial synthesis and achieving complete environmental friendliness. Furthermore, the energy storage scale is unlimited, allowing for both small-scale modular storage and large-scale energy storage. This invention also enables cogeneration, providing a new pathway for achieving carbon peaking and carbon neutrality in the heating sector. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the energy storage function in Embodiment 1 of the present invention;

[0032] Figure 2 This is a schematic diagram illustrating the energy storage and heating functions of Embodiment 2 of the present invention. Detailed Implementation

[0033] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0034] like Figure 1-2As shown, a combined thermal energy and pressure potential energy storage cogeneration system includes an expander. The inlet of the expander is connected to a high-pressure carbon dioxide storage heat exchanger via a valve. The outlet of the high-pressure carbon dioxide storage heat exchanger is connected to a low-pressure carbon dioxide storage heat exchanger via a valve. The inlet of the high-pressure carbon dioxide storage heat exchanger is connected to a carbon dioxide compressor via a valve, and the outlet is connected to the expander via a valve. The inlet of the low-pressure carbon dioxide storage heat exchanger is connected to the expander via a valve, and the outlet is connected to the carbon dioxide compressor via a valve. The inlet of the carbon dioxide compressor is connected to the low-pressure carbon dioxide storage heat exchanger via a valve, and the outlet is connected to the high-pressure carbon dioxide storage heat exchanger via a valve.

[0035] The low-temperature thermal storage tank is filled with low-temperature thermal storage material. It is equipped with a low-pressure carbon dioxide storage heat exchanger and a heat pump evaporator, which exchange heat with the low-temperature thermal storage material.

[0036] The high-temperature thermal storage tank is filled with high-temperature thermal storage material. It is equipped with a high-pressure carbon dioxide storage heat exchanger, a heat pump energy storage heat exchanger, and a high-temperature heating heat exchanger, which exchange heat with the high-temperature thermal storage material.

[0037] Low-temperature thermal energy storage materials are filled into low-temperature thermal energy storage tanks to store low-temperature thermal energy and exchange heat with low-pressure carbon dioxide storage heat exchangers and heat pump evaporators. High-temperature thermal energy storage materials are filled into low-temperature thermal energy storage tanks to store high-temperature thermal energy and exchange heat with high-pressure carbon dioxide storage heat exchangers, heat pump energy storage heat exchangers, and high-temperature heating heat exchangers. Specific Implementation Example 1:

[0039] The working process of a combined thermal energy and pressure potential energy storage cogeneration system includes four sub-processes: main energy storage, power generation, auxiliary energy storage, and heat dissipation. Figure 1 As shown:

[0040] Main energy storage process: Fifth valve 175 and sixth valve 176 are opened, first valve 171 and second valve 172 are closed, and carbon dioxide compressor 4 operates, continuously drawing and compressing carbon dioxide from low-pressure carbon dioxide storage heat exchanger 3 and pumping it into high-pressure carbon dioxide storage heat exchanger 2. During this process, carbon dioxide absorbs heat from low-temperature heat storage material 6 through low-pressure carbon dioxide storage heat exchanger 3 and releases heat to high-temperature heat storage material 8 through high-pressure carbon dioxide storage heat exchanger 2. This process converts the electrical energy driving the compressor and some of the thermal energy in low-temperature heat storage material 6 into the pressure potential energy of carbon dioxide and the thermal energy in high-temperature heat storage material, which are then stored. The temperature and pressure of carbon dioxide in high-pressure carbon dioxide storage heat exchanger 2 increase, and the temperature of high-temperature heat storage material 8 in high-temperature heat storage tank 7 also increases.

[0041] Power generation process: First valve 171 and second valve 172 open, fifth valve 175 and sixth valve 176 close. Carbon dioxide from the high-pressure carbon dioxide storage heat exchanger 2 continuously flows into the low-pressure carbon dioxide storage heat exchanger 3 due to the pressure difference, driving the expander 1 to perform work. This process converts the pressure potential energy of the carbon dioxide in the high-pressure carbon dioxide storage heat exchanger 2 and part of the thermal energy in the high-temperature heat storage material 8 into the mechanical energy of the expander, which can then be converted into electrical energy. The temperature and pressure of the carbon dioxide in the high-pressure carbon dioxide storage heat exchanger 2 decrease, and the temperature of the high-temperature heat storage material 8 in the high-temperature heat storage tank 7 also decreases.

[0042] Auxiliary energy storage process: At the end of the power generation process, the temperature of the high-temperature thermal storage material 8 in the high-temperature thermal storage tank 7 decreases. In the early stage of the main energy storage process, before the temperature of the high-temperature thermal storage material 8 rises to a certain level, a heat pump system can be used to transfer some of the heat from the low-temperature thermal storage material 6 in the low-temperature thermal storage tank 5 to the high-temperature thermal storage material 8 in the high-temperature thermal storage tank 7. The electrical energy driving the heat pump compressor 12 and some of the thermal energy from the low-temperature thermal storage material 6 are stored in the high-temperature thermal storage material 8 in the form of high-temperature thermal energy. The specific process is as follows: third valve 173, third... Valve 174, valve 177, valve 178, valve 1715, and valve 1716 are opened, while valve 179, valve 1710, valve 1711, and valve 1712 are closed. The heat pump working fluid absorbs the low-temperature heat energy from the low-temperature heat storage material 6 in the heat pump evaporator 9, and after evaporation, it enters the heat pump compressor 12. After being compressed by the heat pump compressor 12, it enters the heat pump energy storage heat exchanger 10, where the heat is transferred to the high-temperature heat storage material 8 and stored.

[0043] Heat dissipation process: All equipment and pipes in the above system are externally insulated. As the system continues to operate, the heat inside the system will increase due to friction loss and other reasons, and it will be necessary to dissipate some of the heat when necessary.

[0044] During the heat dissipation process, valves 174, 179, 1710, 1711, and 1712 are opened, while valves 173, 1715, and 1716 are closed. The heat pump working fluid absorbs heat from the low-temperature heat storage material 6 in the heat pump evaporator 9, and is then pumped into the cooler 14 by the working fluid pump 13. After exchanging heat with the external cold source, it returns to the heat pump evaporator 9, forming a closed-loop cycle. Specific Implementation Example 2:

[0046] A combined thermal energy and pressure potential energy storage cogeneration system includes an expander 1, whose inlet is connected to a high-pressure carbon dioxide storage heat exchanger 2 via a valve, and whose outlet is connected to a low-pressure carbon dioxide storage heat exchanger 3 via a valve. Its function is to use the carbon dioxide expansion process to drive rotation, which can drive a generator to generate electricity.

[0047] The high-pressure carbon dioxide storage heat exchanger 2 has its inlet connected to the carbon dioxide compressor 4 via a valve, and its outlet connected to the expander 1 via a valve. Its function is to store high-pressure carbon dioxide and exchange heat with the high-temperature heat storage material 8.

[0048] The low-pressure carbon dioxide storage heat exchanger 3 has its inlet connected to the expander 1 via a valve and its outlet connected to the carbon dioxide compressor 4 via a valve. Its function is to store low-pressure carbon dioxide and exchange heat with the low-temperature heat storage material 6.

[0049] The carbon dioxide compressor 4 has its inlet connected to the low-pressure carbon dioxide storage heat exchanger 3 via a valve, and its outlet connected to the high-pressure carbon dioxide storage heat exchanger 2 via a valve. Its function is to compress carbon dioxide.

[0050] The low-temperature heat storage tank 5 is filled with low-temperature heat storage material 6. The low-pressure carbon dioxide storage heat exchanger 3 and the heat pump evaporator 9 are both built into it and exchange heat with the low-temperature heat storage material 6.

[0051] Low-temperature thermal energy storage material 6 is filled in the low-temperature thermal energy storage tank 5 to store low-temperature thermal energy and exchange heat with the low-pressure carbon dioxide storage heat exchanger 3 and the heat pump evaporator 9.

[0052] The high-temperature heat storage tank 7 is filled with high-temperature heat storage material 8. The high-pressure carbon dioxide storage heat exchanger 2, the heat pump energy storage heat exchanger 10, and the high-temperature heating heat exchanger 16 are all built into it and exchange heat with the high-temperature heat storage material 8.

[0053] High-temperature heat storage material 8 is filled into low-temperature heat storage tank 7 to store high-temperature heat energy and exchange heat with high-pressure carbon dioxide storage heat exchanger 2, heat pump energy storage heat exchanger 10, and high-temperature heating heat exchanger 16.

[0054] The heat pump evaporator 9 has its inlet connected to the cooler 14 and the expansion valve 11 via valves, and its outlet connected to the heat pump compressor 12 and the heat pump heating heat exchanger 15 via valves. The heat pump working fluid can exchange heat with the low-temperature heat storage material 6 through it.

[0055] The heat pump energy storage heat exchanger 10 has its inlet connected to the heat pump compressor 12, the working fluid pump 13 and the cooler 14 through valves, and its outlet connected to the expansion valve 11 through a valve. The heat pump working fluid can exchange heat with the high-temperature heat storage material 8 through it.

[0056] The heat pump expansion valve 11 has its inlet connected to the heat pump energy storage heat exchanger 10 and the heat pump heating heat exchanger 15 via valves, and its outlet connected to the heat pump evaporator 9 and the cooler 14 via valves. Its main function is to throttle the heat pump working fluid.

[0057] The heat pump compressor 12 has its inlet connected to the heat pump evaporator 9 and the cooler 14 via valves, and its outlet connected to the heat pump energy storage heat exchanger 10 and the heat pump heating heat exchanger 15 via valves. Its main function is to compress the heat pump working fluid.

[0058] The working fluid pump 13 has its inlet connected to the heat pump evaporator 9 via a valve, and its outlet connected to the cooler 14 via a valve. Its main function is to drive the heat pump working fluid to circulate between the heat pump evaporator 9 and the cooler 14.

[0059] The cooler 14 has its inlet connected to the heat pump evaporator 9 and the heat pump expansion valve 11 via valves, and its outlet connected to the heat pump evaporator 9 and the heat pump compressor 12 via valves. The heat pump working fluid can exchange heat with cold and heat sources outside the system through it.

[0060] The heat exchanger 15 for heat pump heating has its inlet connected to the heat pump compressor 12 via a valve, and its outlet connected to the heat pump expansion valve 11 via a valve. Its function is to use the heat pump system to heat the return water for heating.

[0061] The high-temperature heating heat exchanger 16 is used to heat the return water of the heating system using the high-temperature heat storage material 8.

[0062] The working process of a combined thermal energy and pressure potential energy storage cogeneration system includes five sub-processes: main energy storage, power generation, auxiliary energy storage, heat dissipation, and heating. Figure 2 As shown:

[0063] Main energy storage process: Fifth valve 175 and sixth valve 176 are opened, first valve 171 and second valve 172 are closed, and carbon dioxide compressor 4 operates, continuously drawing and compressing carbon dioxide from low-pressure carbon dioxide storage heat exchanger 3 and pumping it into high-pressure carbon dioxide storage heat exchanger 2. During this process, carbon dioxide absorbs heat from low-temperature heat storage material 6 through low-pressure carbon dioxide storage heat exchanger 3 and releases heat to high-temperature heat storage material 8 through high-pressure carbon dioxide storage heat exchanger 2. This process converts the electrical energy driving the compressor and some of the thermal energy in low-temperature heat storage material 6 into the pressure potential energy of carbon dioxide and the thermal energy in high-temperature heat storage material, which are then stored. The temperature and pressure of carbon dioxide in high-pressure carbon dioxide storage heat exchanger 2 increase, and the temperature of high-temperature heat storage material 8 in high-temperature heat storage tank 7 also increases.

[0064] Power generation process: First valve 171 and second valve 172 open, fifth valve 175 and sixth valve 176 close. Carbon dioxide from the high-pressure carbon dioxide storage heat exchanger 2 continuously flows into the low-pressure carbon dioxide storage heat exchanger 3 due to the pressure difference, driving the expander 1 to perform work. This process converts the pressure potential energy of the carbon dioxide in the high-pressure carbon dioxide storage heat exchanger 2 and part of the thermal energy in the high-temperature heat storage material 8 into the mechanical energy of the expander, which can then be converted into electrical energy. The temperature and pressure of the carbon dioxide in the high-pressure carbon dioxide storage heat exchanger 2 decrease, and the temperature of the high-temperature heat storage material 8 in the high-temperature heat storage tank 7 also decreases.

[0065] Auxiliary energy storage process: At the end of the power generation process, the temperature of the high-temperature thermal storage material 8 in the high-temperature thermal storage tank 7 decreases. In the early stage of the main energy storage process, before the temperature of the high-temperature thermal storage material 8 rises to a certain level, a heat pump system can be used to transfer some of the heat from the low-temperature thermal storage material 6 in the low-temperature thermal storage tank 5 to the high-temperature thermal storage material 8 in the high-temperature thermal storage tank 7. The electrical energy driving the heat pump compressor 12 and some of the thermal energy from the low-temperature thermal storage material 6 are stored in the high-temperature thermal storage material 8 in the form of high-temperature thermal energy. The specific process is as follows: third valve 173, fourth valve 174, seventh valve 177, 178, 15, 1715, and 1616 are open; 179, 10, 1710, 11, 1711, 12, 13, and 1414 are closed. The heat pump working fluid absorbs the low-temperature heat energy from the low-temperature heat storage material 6 in the heat pump evaporator 9, evaporates, and enters the heat pump compressor 12. After being compressed by the heat pump compressor 12, it enters the heat pump energy storage heat exchanger 10, where the heat is transferred to the high-temperature heat storage material 8 and stored.

[0066] Heat dissipation process: All equipment and pipes in the above system are externally insulated. As the system continues to operate, the heat inside the system will increase due to friction loss and other reasons, and it will be necessary to dissipate some of the heat when necessary.

[0067] During the heat dissipation process, valves 174, 179, 1710, 1711, and 1712 are opened, while valves 179, 1715, and 1716 are closed. The heat pump working fluid absorbs heat from the low-temperature heat storage material 6 in the heat pump evaporator 9, and is then pumped into the cooler 14 by the working fluid pump 13. After exchanging heat with the external cold source, it returns to the heat pump evaporator 9, forming a closed-loop cycle.

[0068] Heating process:

[0069] If the heat pump system obtains low-temperature thermal energy from the low-temperature thermal storage material 6, then the third valve 173, the fourth valve 174, the thirteenth valve 1713, the fourteenth valve 1714, the fifteenth valve 1715, and the sixteenth valve 1716 are opened, and the seventh valve 177, the eighth valve 178, the ninth valve 179, the tenth valve 1710, the eleventh valve 1711, and the twelfth valve 1712 are closed. The heat pump working fluid absorbs heat and evaporates in the heat pump evaporator 9, then enters the heat pump compressor 12 to be compressed, and then enters the heat pump heating heat exchanger 15 to heat the heating return water. After passing through the heat pump expansion valve 11 for throttling, it returns to the heat pump evaporator 9, forming a heat pump cycle.

[0070] If the heat pump system obtains low-temperature heat energy from an external heat source, then valves 111, 1212, 1313, 1414, 1515, and 1616 are opened, while valves 177, 188, 199, 1010, 313, and 414 are closed. The heat pump working fluid absorbs heat and evaporates in the cooler 14, then enters the heat pump compressor 12 to be compressed, and then enters the heat pump heat exchanger 15 to heat the return water. After passing through the heat pump expansion valve 11, it returns to the heat pump evaporator 9, forming a heat pump cycle.

[0071] If only a heat pump system is used for heating, then valves 1717 and 1718 are opened, and valves 1719, 1720, 1721, and 1722 are closed. The return water is heated directly by the heat pump heat exchanger 15.

[0072] If the return water cannot reach the required temperature after being heated by the heat pump heat exchanger, then valves 1717 and 1718 are opened, and valves 1719, 1720, 1721, and 1722 are closed. The return water is then heated by the heat pump heat exchanger 15 and then enters the high-temperature heat exchanger 16 for further heating. It then obtains heat from the high-temperature heat storage material and raises its temperature before being used for heating.

[0073] If the heat pump system cannot work to heat, and can only be heated by the high-temperature heat storage material 8, then the twentieth valve 1720, the twenty-first valve 1721, and the twenty-second valve 1722 will be opened, the seventeenth valve 1717 and the eighteenth valve 1718 will be opened, and the nineteenth valve 1719 will be closed. The heating return water will be directly supplied with heat after being heated by the high-temperature heating heat exchanger 16.

[0074] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0075] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for realizing combined thermal energy and pressure potential energy storage for cogeneration, characterized in that: The combined thermal energy and pressure potential energy storage cogeneration system includes an expander. The inlet of the expander is connected to a high-pressure carbon dioxide storage heat exchanger via a valve. The outlet of the high-pressure carbon dioxide storage heat exchanger is connected to a low-pressure carbon dioxide storage heat exchanger via a valve. The inlet of the high-pressure carbon dioxide storage heat exchanger is connected to a carbon dioxide compressor via a valve, and the outlet is connected to the expander via a valve. The inlet of the low-pressure carbon dioxide storage heat exchanger is connected to the expander via a valve, and the outlet is connected to the carbon dioxide compressor via a valve. The inlet of the carbon dioxide compressor is connected to the low-pressure carbon dioxide storage heat exchanger via a valve, and the outlet is connected to the high-pressure carbon dioxide storage heat exchanger via a valve. The low-temperature thermal storage tank is filled with low-temperature thermal storage material. It is equipped with a low-pressure carbon dioxide storage heat exchanger and a heat pump evaporator, which exchange heat with the low-temperature thermal storage material. The high-temperature heat storage tank is filled with high-temperature heat storage material. It is equipped with a high-pressure carbon dioxide storage heat exchanger, a heat pump energy storage heat exchanger, and a high-temperature heating heat exchanger, which exchange heat with the high-temperature heat storage material. Low-temperature thermal energy storage material is filled into a low-temperature thermal energy storage tank to store low-temperature thermal energy and exchange heat with a low-pressure carbon dioxide storage heat exchanger and a heat pump evaporator. High-temperature thermal energy storage material is filled into a low-temperature thermal energy storage tank to store high-temperature thermal energy and exchange heat with a high-pressure carbon dioxide storage heat exchanger, a heat pump energy storage heat exchanger, and a high-temperature heating heat exchanger. The inlet of the heat pump evaporator is connected to the cooler and the expansion valve respectively, and its outlet is connected to the heat pump compressor and the heat pump heating heat exchanger respectively. The heat pump working fluid exchanges heat with the low-temperature heat storage material. The inlet of the heat pump energy storage heat exchanger is connected to the heat pump compressor, the working fluid pump and the cooler respectively, and its outlet is connected to the heat pump expansion valve. The heat pump working fluid exchanges heat with the high-temperature heat storage material. The inlet of the heat pump expansion valve is connected to the heat pump energy storage heat exchanger and the heat pump heating heat exchanger, respectively, and its outlet is connected to the heat pump evaporator and the cooler. The application method of realizing the combined energy storage and cogeneration system of thermal energy and pressure potential energy includes the main energy storage process, the power generation process, the auxiliary energy storage process, the heat dissipation process, and the heat supply process; The main energy storage process is an adiabatic compression process: the low-temperature, low-pressure carbon dioxide in the low-pressure carbon dioxide storage heat exchanger is compressed by the compressor into a high-temperature, high-pressure supercritical state and stored in the high-pressure carbon dioxide storage heat exchanger. At the same time, the carbon dioxide in the low-pressure carbon dioxide storage heat exchanger absorbs heat from the low-temperature heat storage material placed in the low-temperature heat storage tank. On the other hand, after the compressed carbon dioxide enters the high-pressure carbon dioxide storage heat exchanger, it releases some heat. This heat is stored in the high-temperature heat storage material placed in the high-temperature heat storage tank. During this process, the electrical energy that drives the compressor is stored as the pressure potential energy of the supercritical carbon dioxide and the thermal energy of the high-temperature heat storage material. The power generation process is an adiabatic expansion process: supercritical carbon dioxide in the high-pressure carbon dioxide storage heat exchanger drives the expander to do work and then enters the low-pressure carbon dioxide storage heat exchanger. At the same time, the carbon dioxide in the high-pressure carbon dioxide storage heat exchanger absorbs heat from the high-temperature heat storage material, and the heat energy in the high-temperature heat storage material is transferred to the carbon dioxide in the high-pressure carbon dioxide storage heat exchanger and converted into pressure potential energy. On the other hand, after the expanded carbon dioxide enters the low-pressure carbon dioxide storage heat exchanger, it condenses and releases heat, and exchanges heat with the low-temperature heat storage material in the low-temperature heat storage tank. The heat energy is stored in the low-temperature heat storage material in the low-temperature heat storage tank. This process converts the pressure potential energy of carbon dioxide and the heat energy in the high-temperature heat storage material into mechanical energy to drive the expander, and then into electrical energy. The auxiliary energy storage process is a Carnot cycle process: when power generation ends, the temperature of the high-temperature thermal storage material decreases. In the early stage of energy storage, before its temperature rises to a certain level, the heat in the low-temperature thermal storage material is transferred to the high-temperature thermal storage material by a heat pump. The electrical energy driving the heat pump compressor and part of the thermal energy in the low-temperature thermal storage material are stored in the high-temperature thermal storage material in the form of high-temperature thermal energy. The heat dissipation process is a heat exchange process: when the above system dissipates heat, the heat pump working fluid absorbs heat from the low-temperature heat storage material in the heat pump evaporator, and then the working fluid is pumped into the cooler for cooling. Excess heat is carried away by the external cold source of the system. The heating process is a heat exchange process: the return water is heated by the heat pump heat exchanger, which is another condenser of the heat pump, and the heat energy obtained comes from the heat pump system.

2. The method for realizing combined thermal energy and pressure potential energy storage and cogeneration according to claim 1, characterized in that, The inlet of the heat pump compressor is connected to the heat pump evaporator and cooler, and its outlet is connected to the heat pump energy storage heat exchanger and the heat pump heating heat exchanger.

3. The method for realizing combined thermal energy and pressure potential energy storage and cogeneration according to claim 2, characterized in that, The working fluid pump inlet is connected to the heat pump evaporator, and its outlet is connected to the cooler, which causes the heat pump working fluid to circulate between the heat pump evaporator and the cooler. The cooler inlet is connected to the heat pump evaporator and the expansion valve, respectively, and its outlet is connected to the heat pump evaporator and the heat pump compressor. The heat pump working fluid exchanges heat with the cold and heat sources outside the system through it.

4. The method for realizing combined thermal energy and pressure potential energy storage and cogeneration according to claim 3, characterized in that, The low-temperature thermal storage material includes phase change thermal storage material, and the high-temperature thermal storage material includes phase change thermal storage material.

5. The method for realizing combined thermal energy and pressure potential energy storage and cogeneration according to claim 4, characterized in that, The specific process of auxiliary energy storage is as follows: the working fluid absorbs the low-temperature heat energy in the low-temperature heat storage material in the heat pump evaporator, and after evaporation, it is compressed by the heat pump compressor and enters the heat pump energy storage heat exchanger to transfer the heat to the high-temperature heat storage material and store it.

6. The method for realizing combined thermal energy and pressure potential energy storage and cogeneration according to claim 5, characterized in that, In operation, the heat pump system uses a heat pump evaporator as the evaporator to obtain a low-temperature heat source from a low-temperature heat storage material, or uses the aforementioned cooler as the evaporator to obtain a low-temperature heat source from an external heat source.

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