Reversible power generation and heat pump system based on Stirling cycle

Abstract

The present invention discloses a reversible power generation and heat pump system based on Stirling cycle, comprising: a first liquid piston system including a first hydraulic cylinder, a first and a second pressure vessel, a second liquid piston system including a second hydraulic cylinder, a third and a fourth pressure vessel; a first and a second gas piston cylinder, a reversible power device and a multi-stage heat exchange device. The operation process of this system based on Stirling cycle consists of four processes: low-temperature isothermal compression, isochoric heating, high-temperature isothermal expansion and isochoric cooling, while the working principle of the heat pump system is the reverse process of Stirling cycle, and its operation process includes four processes: high-temperature isothermal compression, isochoric cooling, low-temperature isothermal expansion and isochoric heating. Isochoric heating and isochoric cooling use a multi-stage heat exchange device for heat exchange, so that the temperature of the gas increases or decreases during the equal volume migration process, so as to realize the heat recovery process and improve the thermal efficiency. The system of the present invention uses liquid temperature difference to generate electricity, and provides a power generation system with sustainable power generation.

Description

Technical Field

[0001] The present invention belongs to the technical field of compressed air energy storage, and in particular relates to a reversible power generation and heat pump system based on a Stirling cycle. Background Art

[0002] With the development of the power system, new power generation technologies such as solar power generation and waste heat power generation are gaining more and more attention. Solar thermal power generation technology is a technology that uses a large number of reflectors to focus direct solar light, heat the working fluid, and generate high-temperature and high-pressure steam to drive the steam turbine to generate electricity.

[0003] In terms of natural resources, my country is very rich in geothermal resources. However, except for a few medium and high temperature hot water resources used for power generation, the rest are mainly used for building heating, hot spring health care, breeding and planting, etc. On the other hand, in the industrial and living fields, there are a large number of liquids and flue gases containing waste heat and residual heat. These heats are of low taste and quality, and the feasibility of utilization is low. With the continuous progress of social sciences and the continuous development of process requirements for industrial compressed air, some occasions often put forward requirements for temperature and pressure changes of compressed air. For example, in the field of compressed air energy storage technology, when compressed air is stored, low-temperature and low-pressure gas is easy to store; when compressed air is used for power generation, the use of high-temperature and high-pressure gas for power generation can improve the power generation efficiency.

[0004] Most of the existing technologies are based on the Carnot cycle process. Compared with the Carnot cycle process, the Stirling cycle process has a much lower gas pressure after heating than the Carnot cycle process under the same isothermal compression ratio, and has a smaller pressure resistance requirement for the equipment and is less difficult to manufacture. Summary of the invention

[0005] The present invention proposes a reversible power generation and heat pump system based on the Stirling cycle, which generates electricity by using the temperature difference between the liquid in the first temperature range of the first liquid piston cylinder and the liquid in the second temperature range of the second liquid piston cylinder, and provides a power generation system that can generate electricity sustainably. Compared with the Carnot cycle process, for the Stirling cycle process under the same isothermal process compression ratio, the gas pressure after heating is much smaller than that of the Carnot cycle process, and the pressure resistance requirement of the equipment is small, and the actual manufacturing difficulty of the equipment is small.

[0006] A reversible power generation and heat pump system based on Stirling cycle, comprising:

[0007] First to fourth pressure vessels (1, 2, 3, 4), first and second hydraulic cylinders (5, 6), first and second gas piston cylinders (7, 8), first to fourth reversible power devices (9, 10, 11, 12), first and second multi-stage heat exchange devices (13, 14); the first and second pressure vessels (1, 2) are configured to store liquid and gas with a first temperature range, and the third and fourth pressure vessels (3, 4) are configured to store liquid and gas with a second temperature range;

[0008] The first hydraulic cylinder (5) and the first and second pressure vessels (1, 2) form a first liquid piston system for a low-temperature isothermal compression process, wherein the first piston in the first hydraulic cylinder (5) pushes the liquid in the first temperature range in the first hydraulic cylinder (5) into the first pressure vessel (1) or the second pressure vessel (2) to compress the first gas; the second hydraulic cylinder (6) and the third and fourth pressure vessels (3, 4) form a second liquid piston system for a high-temperature isothermal expansion process, wherein the second piston of the second hydraulic cylinder (6) moves under the expansion action of the second gas and drives the fourth reversible power device (12) through a second piston rod connected thereto;

[0009] The low temperature port of the first multi-stage heat exchange device (13) is connected to one of the first and second pressure vessels (1, 2) through valve control, and the high temperature port is connected to one of the third and fourth pressure vessels (3, 4) through valve control; the low temperature port of the second multi-stage heat exchange device (14) is connected to one of the first and second pressure vessels (1, 2) through valve control, and the high temperature port is connected to one of the third and fourth pressure vessels (3, 4) through valve control;

[0010] The first gas piston cylinder (7) and the second gas piston cylinder (8) are respectively used alternately to drive the isochoric heating process and the isochoric cooling process; the first gas piston cylinder (7) is arranged on a pipeline connecting the low-temperature port of the first multi-stage heat exchange device (13) with the first pressure vessel (1) and the second pressure vessel (2) to control the isochoric migration of the gas, and the second gas piston cylinder (8) is arranged on a pipeline connecting the low-temperature port of the second multi-stage heat exchange device (14) with the first pressure vessel (1) and the second pressure vessel (2) to control the isochoric migration of the gas.

[0011] Furthermore, the system includes four Stirling cycle processes, namely:

[0012] In the first process, the low temperature port of the first multi-stage heat exchange device (13) is connected to the first pressure vessel (1) through valve control, and the high temperature port is connected to the fourth pressure vessel (4). The fourth reversible power device (12) controls the movement of the first gas piston rod in the first gas piston cylinder (7) so that the gas in the fourth pressure vessel (4) is isochoricly cooled and migrates to the first pressure vessel (1) through the first multi-stage heat exchange device (13);

[0013] In the second process, the low temperature port of the first multi-stage heat exchange device (13) is connected to the first pressure vessel (1) through valve control, and the high temperature port is connected to the third pressure vessel (3); the low temperature port of the second multi-stage heat exchange device (14) is connected to the second pressure vessel (2) through valve control, and the high temperature port is connected to the fourth pressure vessel (4); the fourth reversible power device (12) controls the movement of the first gas piston rod in the first gas piston cylinder (7) so that the gas in the third pressure vessel (3) is transferred to the first pressure vessel (1) through isochoric cooling by the first multi-stage heat exchange device (13); the second reversible power device (10) controls the movement of the second gas piston rod in the second gas piston cylinder (8) so that the gas in the second pressure vessel (2) isochoric heating by the second multi-stage heat exchange device (14) and isochoric transferring to the fourth pressure vessel (4);

[0014] In the third process, the low temperature port of the second multi-stage heat exchange device (14) is connected to the second pressure vessel (2) through valve control, and the high temperature port is connected to the third pressure vessel (3). The second reversible power device (10) controls the movement of the second gas piston rod in the second gas piston cylinder (8) so that the gas in the third pressure vessel (3) is isochorically cooled and migrates to the second pressure vessel (2) through the second multi-stage heat exchange device (14);

[0015] In the fourth process, the low temperature port of the first multi-stage heat exchange device (13) is connected to the first pressure vessel (1) through valve control, and the high temperature port is connected to the third pressure vessel (3); the low temperature port of the second multi-stage heat exchange device (14) is connected to the second pressure vessel (2) through valve control, and the high temperature port is connected to the fourth pressure vessel (4); the fourth reversible power device (12) controls the movement of the first gas piston rod in the first gas piston cylinder (7) so that the gas in the first pressure vessel (1) is isochorically heated and migrated to the third pressure vessel (3) through the first multi-stage heat exchange device (13); the second reversible power device (10) controls the movement of the second gas piston rod in the second gas piston cylinder (8) so that the gas in the fourth pressure vessel (4) is isochorically cooled and migrated to the second pressure vessel (2) through the second multi-stage heat exchange device (14).

[0016] Preferably, the first to fourth pressure vessels (1, 2, 3, 4) can be used as gas delivery tanks or gas receiving tanks, wherein liquid and gas with a first temperature range in the first and second pressure vessels (1, 2) and liquid and gas with a second temperature range in the third and fourth pressure vessels (3, 4) can be moved in or out.

[0017] Preferably, the first to fourth pressure vessels (1, 2, 3, 4) are provided with heat insulating materials to be heat-insulated from the outside.

[0018] Preferably, the reversible power device (9, 10, 11, 12) has both a power generation mode and an electric mode; in the power generation mode, the reversible power devices (9, 11) are driven by the first and second liquid piston rods to generate electricity, and the reversible power devices (10, 12) are driven by the first and second gas piston rods to generate electricity; in the motor mode, the reversible power devices (9, 11) can use electric energy to drive the first and second liquid piston rods to move, and the reversible power devices (10, 12) can use electric energy to drive the first and second gas piston rods to move.

[0019] Preferably, the first and second multi-stage heat exchange devices (13, 14) adopt non-simultaneous heat recovery.

[0020] Preferably, the first and second multi-stage heat exchange devices (13, 14) are composed of a plurality of water storage tanks connected in series, each of which stores relatively full water of different temperatures.

[0021] Furthermore, when the gas needs to be heated up, the gas valve is controlled so that the gas enters through the high-temperature ports of the first and second multi-stage heat exchange devices (13, 14) and is discharged through the low-temperature ports; when the gas needs to be cooled down, the gas valve is controlled so that the gas enters through the low-temperature ports of the first and second multi-stage heat exchange devices (13, 14) and is discharged through the high-temperature ports.

[0022] Preferably, the first and second multi-stage heat exchange devices (13, 14) are surface heaters or hybrid regenerative heaters.

[0023] Specifically, the surface heater is to connect multiple water tanks filled with water in a certain temperature range in series through exhaust pipes, so that the gas that needs to be heated or cooled does not directly contact the water, and the temperature is increased or reduced by using the heat transfer capacity of the metal pipe.

[0024] Specifically, the hybrid heat recovery heating is to store water in a temperature range close to the full tank in three water tanks, and connect them in series using pipelines for migrating gas, so that the gas that needs to be heated or cooled is in direct contact with the liquid in the water tank.

[0025] Preferably, the water storage tanks of the first and second multi-stage heat exchange devices (13, 14) are provided with circulation pumps to pump liquid within a certain temperature range at the bottom of the water storage tank to the top of the water storage tank.

[0026] Specifically, during the low-temperature isothermal compression process, the first hydraulic cylinder (5), the first pressure vessel (1) and the second pressure vessel (2) all have three states: compression, migration and intake, wherein the intake state of the first pressure vessel (1) spans the first process and the second process, and the intake state of the second pressure vessel (2) spans the third process and the fourth process; during the high-temperature isothermal expansion process, the second hydraulic cylinder (6), the third pressure vessel (3) and the fourth pressure vessel (4) all have three states: migration, expansion and exhaust, wherein the exhaust state of the third pressure vessel (3) spans the second process and the third process, and the exhaust state of the fourth pressure vessel (4) spans the first process and the fourth process; during the isochoric heating process, the first gas piston cylinder (7) and the second gas piston cylinder (8) all have two states: heating and stopping; during the isochoric cooling process, the first gas piston cylinder (7) and the second gas piston cylinder (8) only have one state: cooling.

[0027] Specifically, the isothermal expansion of the gas in the third pressure vessel (3) or the fourth pressure vessel (4) drives the second temperature liquid in the third pressure vessel (3) or the fourth pressure vessel (4) to flow to the second hydraulic cylinder (6) and drives the second piston rod to move so that the reversible power device (11) generates electricity; after the isothermal expansion of the gas in the third pressure vessel (3) or the fourth pressure vessel (4), when the gas migrates from the third pressure vessel (3) or the fourth pressure vessel (4) to the first pressure vessel (1) or the second pressure vessel (2) via the second gas piston cylinder (8) in equal volume, it drives the second gas piston rod so that the reversible power device (12) generates electricity.

[0028] Specifically, during the operation of the heat pump, the first liquid piston system is used for a low-temperature isothermal expansion process. When the gas in the first or second pressure vessel is isothermally expanded at low temperature, the first temperature liquid flows from the first pressure vessel (1) or the second pressure vessel (2) to the first hydraulic cylinder (5), driving the first piston to move and pushing the reversible power device (9) to generate electricity; the second liquid piston system is used for a high-temperature isothermal compression process. After the gas in the third pressure vessel (3) or the fourth pressure vessel (4) is isothermally compressed, when the gas is transferred from the third pressure vessel (3) or the fourth pressure vessel (4) to the first pressure vessel (1) or the second pressure vessel (2) via the second gas piston cylinder (8) in equal volume, it pushes the second gas piston rod to push the reversible power device (12) to generate electricity; the first gas piston cylinder (7) and the second gas piston cylinder (8) are respectively used alternately for driving the isochoric heating process and the isochoric cooling process.

[0029] Preferably, the system further comprises a fifth pressure vessel (15) and a sixth pressure vessel (16); the lower portion of the fifth pressure vessel (15) is connected to the first hydraulic cylinder (5), and the upper portion is connected to one of the first gas piston cylinder (7) and the second gas piston cylinder (8) through a gas valve control; the lower portion of the sixth pressure vessel (16) is connected to the second hydraulic cylinder (6), and the upper portion is connected to one of the first gas piston cylinder (7) and the second gas piston cylinder (8) through a gas valve control; the fifth pressure vessel (15) stores liquid in a first temperature range, and the sixth pressure vessel (16) stores liquid in a second temperature range.

[0030] Preferably, the system further comprises a third hydraulic cylinder (17), a fourth hydraulic cylinder (18), a seventh pressure vessel (19), and an eighth pressure vessel (20); the first hydraulic cylinder (5) is connected in parallel with the third hydraulic cylinder (17), and the second hydraulic cylinder (6) is connected in parallel with the fourth hydraulic cylinder.

[0031] Preferably, the first temperature range is lower than the second temperature range. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In the drawings of the embodiments of the present invention, only the structures related to the embodiments of the present invention are involved, and other structures can refer to the general design. In the case of no conflict, the features in the same embodiment and different embodiments of the present invention can be combined with each other.

[0033] Figure 1 A schematic structural diagram of a reversible power generation and heat pump system based on a Stirling cycle provided in one embodiment of the present invention;

[0034] Figures 2A-2D Schematic diagram of four operation processes of a reversible power generation and heat pump system based on Stirling cycle according to one embodiment of the present invention, wherein Figure 2A This is a schematic diagram of the operation of the first process. Figure 2B is the operation diagram of the second process, Figure 2C This is the operation diagram of the third process. Figure 2D is a schematic diagram of the operation of the fourth process;

[0035] Figures 3A-3E The following are two schematic structural diagrams of a multi-stage heat exchange device for a reversible power generation and heat pump system based on a Stirling cycle according to an embodiment of the present invention; Figure 3A , Figure 3B For surface heaters, Figure 3C It is a hybrid regenerative heater. Figure 3D For fixed plate and tube heat exchanger, Figure 3E This is the working principle diagram of the heat transfer process of the heat storage body;

[0036] Figure 4A structural diagram of a reversible power generation and heat pump system based on a Stirling cycle with an external heat exchange implementation structure provided according to an embodiment of the present invention;

[0037] Figure 5 A schematic diagram of the structure of a reversible power generation and heat pump system based on a Stirling cycle with a three-state continuous operation structure provided according to an embodiment of the present invention. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical scheme and advantages of the implementation of the present invention clearer, the technical scheme in the embodiment of the present invention will be described in more detail below in conjunction with the drawings in the embodiment of the present invention. In the drawings, the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The described embodiments are part of the embodiments of the present invention, not all of the embodiments. The embodiments described below with reference to the drawings are exemplary and are intended to be used to explain the present invention, and cannot be understood as limitations on the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present invention. In the drawings of the embodiments of the present invention, only the structures involved in the embodiments of the present invention are involved, and other structures can refer to the general design. In the absence of conflict, the features in the same embodiment and different embodiments of the present invention can be combined with each other.

[0039] Unless otherwise defined, the technical or scientific terms used in the present invention shall have the usual meanings understood by persons with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. Words such as "include" or "comprise" and the like mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connect" or "connected" and the like are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect.

[0040] At present, the conventional solar thermal power generation technology is not efficient, and the utilization efficiency of solar energy is low. On the other hand, the taste and quality of liquids and flue gases containing waste heat and residual heat in the industrial and living fields are not high, and the feasibility of utilization is low; most of them are discarded, which not only causes waste of resources, but also pollutes the environment. Similarly, except for a few medium and high temperature hot water resources used for power generation, the rest of my country's geothermal resources are mainly used for building heating, hot spring health care, and breeding and planting. A large amount of geothermal resources lack direct heat demand and are therefore idle and wasted. Therefore, the present invention aims to effectively utilize these heat sources and use these energy sources for power generation at the same time, which can reduce the waste of resources and reduce pollution.

[0041] Figure 1 FIG. 1 is a schematic diagram of a reversible power generation and heat pump system based on a Stirling cycle according to an embodiment of the present invention. Figure 1 As shown, the first pressure vessel 1 and the second pressure vessel 2 are configured to store liquids and gases in a first temperature range; the third pressure vessel 3 and the fourth pressure vessel 4 are configured to store liquids and gases in a second temperature range; the first hydraulic cylinder 5 connects the first pressure vessel 1 and the second pressure vessel 2 to form a first liquid piston system, and the second hydraulic cylinder 6 connects the third pressure vessel 3 and the fourth pressure vessel 4 to form a second liquid piston system. Four processes are set to form a Stirling cycle. The low-temperature port of the first multi-stage heat exchange device 13 is connected to one of the first pressure vessel 1 and the second pressure vessel 2 through valve control, and the high-temperature port is connected to one of the third pressure vessel 3 and the fourth pressure vessel 4 through valve control; the low-temperature port of the second multi-stage heat exchange device 14 is connected to one of the first pressure vessel 1 and the second pressure vessel 2 through valve control, and the high-temperature port is connected to one of the third pressure vessel 3 and the fourth pressure vessel 4 through valve control; the first gas piston cylinder 7 is set at the low-temperature port of the first multi-stage heat exchange device 13 and the first pressure vessel 1 and the second pressure vessel The pipeline connected to the pressure vessel 2 is used to control the isovolumetric migration of gas. The second gas piston cylinder 8 is arranged on the pipeline connected to the low temperature port of the second multi-stage heat exchange device 14 and the first pressure vessel 1 and the second pressure vessel 2 to control the isovolumetric migration of gas. The first hydraulic cylinder 5 is provided with a first liquid piston and a first liquid piston rod connected thereto. The second hydraulic cylinder 6 is provided with a second liquid piston and a second liquid piston rod connected thereto. The first gas piston cylinder 7 is provided with a first gas piston and a first gas piston rod connected thereto. The second gas piston cylinder 8 is provided with a second gas piston and a second gas piston rod connected thereto. The first liquid piston pushes the liquid in the first temperature range in the first hydraulic cylinder 5 into the first pressure vessel 1 or the second pressure vessel 2 to compress the first gas. The first gas piston is configured to move under the expansion of the second gas to drive the fourth reversible power device 12.

[0042] FIG2 is a schematic diagram of four Stirling cycle processes in a reversible power generation and heat pump system based on the Stirling cycle according to an embodiment of the present invention, wherein the gas valve and the liquid valve are shaded to indicate that the valve is open, and the unshaded valve is closed. The arrows represent the flow direction of the liquid in the pipeline, and the gray arrows represent the flow direction of the gas in the pipeline.

[0043] Figure 2A: is a schematic diagram of the operation of the first process. At the beginning of the black process, the first pressure vessel 1 is full of liquid, the second pressure vessel 2 is full of gas, the volume of gas in the third pressure vessel 3 is V1, and the volume of gas in the fourth pressure vessel 4 is V2. Open the liquid valves F1, F4, F5, F8 and the gas valves F9, F15, F18, F19. In the first process, the first pressure vessel 1 is in the intake state, the second pressure vessel 2 is in the compression state, the second gas piston cylinder 8 is in the stop state, the third pressure vessel 3 is in the expansion state, the fourth pressure vessel 4 is in the migration state, and the first gas piston cylinder 7 is in the working state; the first reversible power device 9 is in the motor state to drive the first liquid piston rod to move and press the liquid in the first temperature range in the first hydraulic cylinder 5 into the second pressure vessel 2. The liquid in the first temperature range isothermally compresses the gas in the second pressure vessel 2, and the first pressure vessel 1 also presses the liquid in the first temperature range in the first pressure vessel 1 into the first liquid pressure cylinder 5 due to continuous intake of gas, until the volume of gas in the first pressure vessel 1 becomes V2, and the gas in the second pressure vessel 2 is isothermally compressed. compression, and the final volume is V1; while isothermally compressed in the second pressure vessel 2, the high-temperature and high-pressure second gas is isothermally expanded in the third pressure vessel 3, and at the same time, the liquid in the second temperature range in the third pressure vessel 3 is pressed into the second hydraulic cylinder 6, and hydraulic pressure is applied to the second hydraulic cylinder 6 to push the second liquid piston rod to move and drive the third reversible power device 11 to generate electricity; the second temperature liquid in the second hydraulic cylinder 6 is therefore also pressed into the fourth pressure vessel 4 until the fourth pressure vessel 4 is full of liquid; the second gas in the fourth pressure vessel 4 is also exhausted under the push of the second temperature liquid in the second hydraulic cylinder 6, and this second gas is cooled by the multi-stage heat exchange device 13 and then migrated to the first pressure vessel 1 through the first gas piston cylinder 7 with equal volume, and during the migration process, it pushes the first gas piston rod of the first gas piston cylinder 7 to move, so that the fourth reversible power device 12 generates electricity.

[0044] Figure 2BSchematic diagram of the operation of the second process. In the second process, open the liquid valves F1, F4, F5, F8 and the gas valves F9, F12, F13, F16, F18, F19, F21, F24. During the operation of the second process, the first pressure vessel 1 is in the intake state, the second pressure vessel 2 is in the removal state, the first gas piston cylinder 7 is in the working state, the third pressure vessel 3 is in the removal state, the fourth pressure vessel 4 is in the intake state, and the second gas piston cylinder 8 is in the working state; the first reversible power device 9 drives the first liquid piston rod to move to press the liquid in the first temperature range in the first hydraulic cylinder 5 into the second pressure vessel 2, and remove the gas in the second pressure vessel 2 into the second gas piston cylinder 8; the second reversible power device 10 It is in the electric state and drives the first gas piston rod to move the gas in the second gas piston cylinder 8 through the multi-stage heat exchange device 14 to transfer the gas to the fourth pressure vessel 4 by isochoric temperature increase, so that the liquid in the second temperature range in the fourth pressure vessel 4 is pressed into the second hydraulic cylinder 6, and then the second liquid piston rod is driven to move and the third reversible power device 11 is determined to generate electricity. At the same time, the liquid in the second temperature range in the second hydraulic cylinder 6 enters the third pressure vessel 3, and the second gas in the third pressure vessel 3 is discharged. After cooling through the multi-stage heat exchange device 13, it is transferred from the first gas piston cylinder 7 to the first pressure vessel 1 by isochoric volume. During the migration process, it drives the second gas piston rod in the first gas piston cylinder 7 to move and the fourth reversible power device 12 is generated. Finally, the first pressure vessel 1 is full of gas, the second pressure vessel 2 is full of liquid, the gas volume in the third pressure vessel 3 is V2, and the gas volume in the fourth pressure vessel 4 is V1.

[0045] Figure 2CSchematic diagram of the operation of the third process. In the third process, open the liquid valves F1, F4, F5, F8 and the gas valves F12, F14, F21, F24. During the operation of the third process, the first pressure vessel 1 is in a compressed state, the second pressure vessel 2 is in an intake state, the first gas piston cylinder 7 is in a stopped state, the third pressure vessel 3 is in a migration state, the fourth pressure vessel 4 is in an expansion state, and the second gas piston cylinder 8 is in a working state; the first reversible power device 9 is in a motor rotation state and drives the first liquid piston rod to move to press the liquid in the first temperature range in the first hydraulic cylinder 5 into the first pressure vessel 1, and the liquid in the first temperature range isothermally compressed in the first pressure vessel 1; the second pressure vessel 2 also presses the liquid in the first temperature range in the second pressure vessel 2 into the first liquid pressure cylinder 5 due to continuous intake of gas, until the volume of the gas in the second pressure vessel 2 is V2, and the gas in the first pressure vessel 1 is V3. The volume of the existing gas after isothermal compression is V1; while isothermally compressed in the first pressure vessel 1, the high-temperature and high-pressure gas is isothermally expanded in the fourth pressure vessel 4, and at the same time, the liquid in the second temperature range in the fourth pressure vessel 4 is pressed into the second hydraulic cylinder 6, and hydraulic pressure is applied to the second hydraulic cylinder 6 to push the second liquid piston rod to move and drive the third reversible power device 11 to generate electricity; the liquid in the second temperature range in the second hydraulic cylinder 6 is therefore also pressed into the third pressure vessel 3 until the third pressure vessel 3 is full of liquid, and the gas in the third pressure vessel 3 is also exhausted under the push of the liquid in the second temperature range in the second hydraulic cylinder 6, and this gas is cooled by the multi-stage heat exchange device 14 and then migrated to the second pressure vessel 2 through the second gas piston cylinder 8 with equal volume, and during the migration process, it pushes the second gas piston rod of the second gas piston cylinder 8 to move and drives the second reversible power device 10 to generate electricity.

[0046] Figure 2DIt is a schematic diagram of the operation of the fourth process. In the fourth process, the liquid valves F1, F4, F5, F8 and the gas valves F9, F12, F13, F16, F18, F19, F21, F24 are opened; during the operation of the fourth process, the first pressure vessel 1 is in a migration state, the second pressure vessel 2 is in an intake state, the first gas piston cylinder 7 is in a working state, the third pressure vessel 3 is in an intake state, the fourth pressure vessel 4 is in a migration state, and the second gas piston cylinder 8 is in a working state; the first reversible power device 9 drives the first liquid piston rod to move to press the liquid in the first temperature range in the first hydraulic cylinder 5 into the first pressure vessel 1, and migrate the gas in the first pressure vessel 1 into the first gas piston cylinder 7, and the fourth reversible power device 12 is in a The electric state drives the second gas piston rod to move the gas in the first gas piston cylinder 7 to the third pressure vessel 3 through the multi-stage heat exchange device 13, so that the liquid in the second temperature range in the third pressure vessel 3 is pressed into the second hydraulic cylinder 6, and then the second liquid piston rod is driven to move and drive the third reversible power device 11 to generate electricity; at the same time, the liquid in the second temperature range in the second hydraulic cylinder 6 enters the fourth pressure vessel 4, so that the gas in the fourth pressure vessel 4 is discharged, and after cooling by the multi-stage heat exchange device 14, the second gas piston cylinder 8 is moved to the second pressure vessel 2 in equal volume, and during the migration process, the second gas piston rod in the second gas piston cylinder 8 is driven to move and drive the second reversible power device 10 to generate electricity. Finally, the first pressure vessel 1 is full of liquid, the second pressure vessel 2 is full of gas, the volume of gas in the third pressure vessel 3 is V1, and the volume of gas in the fourth pressure vessel 4 is V2. The working process of the heat pump system is the reverse process of the Stirling cycle.

[0047] In this embodiment, the system for reversible power generation using liquid temperature difference can realize continuous power generation through the above-mentioned device, and generate electricity by using the temperature difference between the liquid with a lower temperature in the first temperature range and the liquid with a higher temperature in the second temperature range. It should be noted that the distinction between the first gas and the second gas is only to more clearly illustrate the working principle of the system for power generation using liquid temperature difference provided by the present invention, and the specific components of the first gas and the second gas can be the same; in addition, the first gas has a low temperature and low pressure state, and also has a high temperature and high pressure state, and the second gas has a high temperature and high pressure state, and also has a low temperature and low pressure state, and the present invention does not limit this. In addition, the above-mentioned liquid with a first temperature range can be directly a liquid containing waste heat and residual heat in geothermal resources or industrial and living fields, so as to directly utilize the above-mentioned thermal energy for power generation, or it can be a liquid heated by the above-mentioned geothermal resources or industrial and living fields containing waste heat and residual heat, flue gas with waste heat or residual heat, or solar energy and other energy sources. It is worth noting that, due to the high temperatures of the third pressure vessel and the fourth pressure vessel, the work done by the isothermal expansion of the high-temperature and high-pressure gas is greater than the work done by compressing the low-temperature and low-pressure gas. Therefore, the system for power generation using liquid temperature difference provided in this embodiment uses the compression and expansion of gas as a medium to realize the utilization of thermal energy and power generation, and does not require additional high-pressure gas. Of course, the present invention includes but is not limited to this. If there is high-pressure gas or high-temperature and high-pressure gas that can be utilized in the use environment, the high-pressure gas or high-temperature and high-pressure gas can also be connected to the system for power generation using liquid temperature difference provided in this embodiment for utilization.

[0048] In a preferred embodiment, Figure 1 As shown, in order to better achieve isothermal compression of the low-temperature and low-pressure first gas in the first pressure vessel 1 and the second pressure vessel 2, the first pressure vessel 1 may include a first circulation pump, and the second pressure vessel 2 may include a second circulation pump. The bottoms of the first pressure vessel 1 and the second pressure vessel 2 are respectively connected to the tops of the first pressure vessel 1 and the second pressure vessel 2, so as to pump the liquid in the first temperature range at the bottom of the first pressure vessel 1 and the second pressure vessel 2 to the tops of the first pressure vessel 1 and the second pressure vessel 2, so as to better achieve heat exchange between the liquid in the first temperature range and the first gas.

[0049] The reversible power device in the present invention has both a power generation mode and an electric mode, and can use electric energy to reversely drive the piston rod to move. In the power generation mode, the reversible power device is driven by the piston rod to generate electricity; in the motor mode, the reversible power device can use electric energy to reversely drive the piston rod to move. The reversible power device can be composed of a linear generator or a crank generator; it can also be an electric cylinder that is a mixture of a motor and a lead screw; it can also be realized by a virtual pumped storage composed of a hydraulic cylinder, a water pump, and a water turbine.

[0050] As a preferred embodiment, Figure 1 As shown, in order to better achieve isothermal expansion of the high-temperature and high-pressure second gas in the third pressure vessel 3 and the fourth pressure vessel 4, the third pressure vessel 3 may include a third circulation pump, and the fourth pressure vessel 4 may include a fourth circulation pump, so as to connect the bottoms of the third pressure vessel 3 and the fourth pressure vessel 4 to the tops of the third pressure vessel 3 and the fourth pressure vessel 4, respectively, so as to pump the liquid in the second temperature range at the bottom of the third pressure vessel 3 and the fourth pressure vessel 4 to the tops of the third pressure vessel 3 and the fourth pressure vessel 4, so as to better achieve heat exchange between the liquid in the second temperature range and the second gas.

[0051] Heat recovery is the transfer of heat from one medium to another. The multi-stage heat exchange device is essentially a heat storage device that stores heat and exchanges heat when the gas passes through. Figure 3 is a schematic diagram of the structure of a multi-stage heat exchange device in a reversible power generation and heat pump system based on a Stirling cycle according to an embodiment of the present invention. Figure 3A and Figure 3B For surface heaters, Figure 3C It is a hybrid regenerative heater. The two groups of heat exchange devices are respectively composed of a plurality of water storage tanks connected in series, each of which stores relatively full water at different temperatures. The low temperature port of the first multi-stage heat exchange device 13 is connected to one of the first pressure vessel 1 and the second pressure vessel 2 through valve control, and the high temperature port is connected to one of the third pressure vessel 3 and the fourth pressure vessel 4 through valve control; the low temperature port of the second multi-stage heat exchange device 14 is connected to one of the first pressure vessel 1 and the second pressure vessel 2 through valve control, and the high temperature port is connected to one of the third pressure vessel 3 and the fourth pressure vessel 4 through valve control. The multi-stage heat exchange devices 13 and 14 realize the isochoric heating and isochoric cooling processes in the Stirling cycle. After one cycle, the order of the two multi-stage heat exchange devices 13 and 14 is changed by the valve, so that the multi-stage heat exchange device that heated up in the previous cycle is changed to cooling, and the multi-stage heat exchange device that cooled down in the previous cycle is changed to heating, thereby improving the utilization rate of the device.

[0052] Surface heaters connect multiple water tanks filled with water in a certain temperature range in series through exhaust pipes, so that the gas that needs to be heated or cooled does not come into direct contact with the water, and the heat transfer capacity of the metal pipe is used to heat or cool the gas. Due to the heat transfer resistance of the metal, the heated gas cannot reach the saturation temperature of the water, so its thermal economy is lower than that of the hybrid regenerative heater, but the regenerative heating system it forms is simple, easy to operate, and has a small workload. Figure 3B The pipe adopts a curved structure, which increases the contact time between the gas and the pressure vessel, making the heat exchange more sufficient.

[0053] A regenerative heater in which the heating water and the heated gas are directly mixed is a hybrid regenerative heater, such as Figure 3C As shown. In the hybrid regenerative heater, three water tanks are used to store water in a temperature range close to the full tank, and are connected in series using a gas transfer pipeline, so that the gas that needs to be heated or cooled is in direct contact with the liquid in the water tank. The advantages of this heater are good heat transfer effect, the gas temperature can reach the saturation temperature under the pressure of the heating water, simple structure and low cost; the disadvantage is that when the water tank is full of liquid, adding gas will bring out part of the water due to the presence of a certain volume of gas, which is not conducive to use.

[0054] Figure 3D It is a fixed plate and tube heat exchanger. Plate heat exchanger is an ideal equipment for heat exchange between liquid and liquid, liquid and steam. It is a new type of high-efficiency heat exchanger made of a series of metal sheets with a certain corrugated shape. Plate heat exchanger is a heat exchanger made of thin metal plates pressed into heat exchange plates with a certain corrugated shape, then stacked and fastened with plywood and bolts. Thin rectangular channels are formed between various plates, and heat exchange is carried out through half a plate. The working fluid flows through the narrow and tortuous channel formed between the two plates. The cold and hot fluids pass through the flow channel in turn, and there is an interlayer plate in the middle to separate the fluids, and heat is exchanged through this plate. The structure and heat exchange principle of the plate heat exchanger determine that it has the characteristics of compact structure, small footprint, high heat transfer efficiency, large operational flexibility, wide application range, small heat loss, easy installation and cleaning.

[0055] Figure 3E The working principle diagram of the heat transfer process of the heat storage body. The heat storage body is installed in the heat storage chamber or directly in the burner. It is one of the key components in the heat storage combustion system. The temperature benefit and thermal efficiency of the heat storage heat exchange system directly depend on the performance of the heat storage body. There are three main types of heat storage bodies: honeycomb ceramics, heat storage balls and heat storage tubes. Honeycomb ceramic heat storage bodies are currently the most important heat storage body materials because of their small size, light weight, large specific surface area, high refractoriness and large heat transfer capacity. As shown in the figure, the working principle of the heat transfer process of the honeycomb ceramic heat storage body is that when the flue gas flows through the honeycomb body, the flue gas transfers its own heat to the honeycomb body, the honeycomb body stores heat, and the temperature gradually increases; when the cold fluid flows through, the cold fluid obtains heat from the honeycomb body, and the temperature of the honeycomb body gradually decreases. This is repeated to form a non-steady-state heat transfer process. In this way, the combustion-supporting air passing through the honeycomb body reaches a predetermined high temperature, and the flue gas passing through drops to a predetermined low temperature, and the honeycomb body transfers the sensible heat in the high-temperature flue gas to the combustion-supporting air.

[0056] Preferably, if Figure 3CAs shown, in order to better realize the heat recovery of gas in the multi-stage heat exchange device, a circulation pump is added to the water storage tank of the multi-stage heat exchange device to connect the bottom of the water storage tank with the top of the water storage tank, so as to pump the liquid with a certain temperature range at the bottom of the water storage tank to the top of the water storage tank, so as to better realize the heat exchange between the liquid with a certain temperature in the multi-stage heat exchange device and the gas that needs to be heated or cooled, thereby improving the thermal efficiency.

[0057] The multi-stage heat exchange device in the present invention adopts non-simultaneous heat recovery. The heat recovery process includes simultaneous heat recovery and non-simultaneous heat recovery. Simultaneous heat recovery means that there are two heat exchange parts in the same device, one for heating and the other for cooling, and they are carried out simultaneously; non-simultaneous heat recovery means that the same heat recovery device is used to heat up first and then cool down. The two processes are not carried out at the same time and there is a sequence. Since heating and cooling are completed in the same heat exchange device, non-simultaneous heat recovery can ensure that the temperature of the heat exchange device is kept within a certain range, achieve heat recovery, and improve thermal efficiency.

[0058] Heat pump is a highly efficient energy-saving device that fully utilizes low-grade thermal energy. Heat can be transferred spontaneously from a high-temperature object to a low-temperature object, but not spontaneously in the opposite direction. The working principle of a heat pump is to force heat from a low-temperature object to a high-temperature object in a reverse cycle. It consumes only a small amount of reverse cycle net work to obtain a large amount of heat supply, and can effectively utilize the low-grade thermal energy that is difficult to use to achieve energy saving. During the operation of the heat pump of the system of the present invention, the first liquid piston system is used for a low-temperature isothermal expansion process. When the gas in the first pressure vessel (1) or the second pressure vessel (2) is isothermally expanded at low temperature, the first temperature liquid flows from the first pressure vessel (1) or the second pressure vessel (2) to the first hydraulic cylinder (5), driving the first piston to move and pushing the reversible power device (9) to generate electricity; the second liquid piston system is used for a high-temperature isothermal compression process. After the gas in the third pressure vessel (3) or the fourth pressure vessel (4) is isothermally compressed, when the gas is transferred from the third pressure vessel (3) or the fourth pressure vessel (4) to the first pressure vessel (1) or the second pressure vessel (2) via the first gas piston cylinder (7) in equal volume, it pushes the first gas piston rod to push the reversible power device (12) to generate electricity; the first gas piston cylinder (7) and the second gas piston cylinder (8) are respectively used alternately for driving the isochoric heating process and the isochoric cooling process.

[0059] Figure 4 A reversible power generation and heat pump system based on a Stirling cycle with an external heat exchange implementation structure is provided according to an embodiment of the present invention, such as Figure 4 As shown, the interior of the dotted box is divided into an external heat exchange implementation structure. Figure 4 The system structure is in Figure 1The fifth pressure vessel 15, the sixth pressure vessel 16, the gas valves F25, F26, F27, F28 and the liquid valves F29, F30, F31, F32 are added to the structure of the reversible power generation and heat pump system based on the Stirling cycle. The lower part of the fifth pressure vessel 15 is connected to the first hydraulic cylinder 5, and the upper part is connected to the first gas piston cylinder 7 and the second gas piston cylinder 8 through the control of the gas valve; the lower part of the sixth pressure vessel 16 is connected to the second hydraulic cylinder 6, and the upper part is connected to the first gas piston cylinder 7 and the second gas piston cylinder 8 through the control of the gas valve. The fifth pressure vessel 15 is filled with liquid in the first temperature range, and the sixth pressure vessel 16 is filled with liquid in the second temperature range. When the reversible power generation and heat pump system based on the Stirling cycle starts to operate, the liquid valves F30 and F32 are opened, so that the first hydraulic cylinder 5, the first pressure vessel 1 and the second pressure vessel 2 form a third liquid piston system, and the second hydraulic cylinder 6, the third pressure vessel 3 and the fourth pressure vessel 4 form a fourth liquid piston system. After running for a certain period of time, since it is necessary to always keep the temperatures of the liquid in the first temperature range and the liquid in the second temperature range unchanged, the liquid valves F30 and F32 are closed, and the liquid valves F29 and F31 are opened, so that the first hydraulic cylinder 5, the fifth pressure vessel 15 and the second pressure vessel 2 form a fifth liquid piston system; and the second hydraulic cylinder 6, the sixth pressure vessel 16 and the fourth pressure vessel 4 form a sixth liquid piston system.

[0060] Figure 5 The schematic diagram of the structure of a reversible power generation and heat pump system based on Stirling cycle with three-state continuous operation is provided according to an embodiment of the present invention. Figure 5 As shown, the three-state continuous operation system structure is Figure 1The third hydraulic cylinder 17, the fourth hydraulic cylinder 18, the seventh pressure vessel 19, and the eighth pressure vessel 20 are added to the reversible power generation and heat pump system based on the Stirling cycle. When connected, the first hydraulic cylinder is connected in parallel with the third hydraulic cylinder, and the second hydraulic cylinder is connected in parallel with the fourth hydraulic cylinder. That is, the first hydraulic cylinder 5 is connected to the first pressure vessel 1 and the second pressure vessel 2, the third hydraulic cylinder 17 is connected to the first pressure vessel 1 and the seventh pressure vessel 19; the second hydraulic cylinder 6 is connected to the third pressure vessel 3 and the fourth pressure vessel 4, and the fourth hydraulic cylinder 18 is connected to the second pressure vessel 3 and the eighth pressure vessel 20. The operation process of this system is basically the same as the cycle process of the reversible power generation and heat pump system based on the Stirling cycle, but due to the addition of two hydraulic cylinders and two pressure vessels, it is ensured that the first pressure vessel 1, the second pressure vessel 2 and the seventh pressure vessel 19 are respectively in the three states of migration, expansion and exhaust in one cycle, and the third pressure vessel 3, the fourth pressure vessel 4 and the eighth pressure vessel 20 are respectively in the three states of migration, expansion and exhaust in one cycle, ensuring that the reversible power generation and heat pump system of the Stirling cycle operates continuously in one cycle. The power generation process is as follows: the second gas is isothermally expanded in the third pressure vessel 3, the fourth pressure vessel 4 and the eighth pressure vessel 20, so that the second temperature liquid generates hydraulic pressure in the second hydraulic cylinder 6 or the fourth hydraulic cylinder 18 to push the second liquid piston rod or the fourth liquid piston rod to move, so that the third reversible power device or the sixth reversible power device generates power; when the second gas is cooled by the multi-stage heat exchange device and migrates from the second gas piston cylinder 8 to the first pressure vessel 1, the second pressure vessel 2 or the seventh pressure vessel 19 in equal volume, the second gas pushes the second gas piston rod of the second gas piston cylinder 8 to move during the migration process, so that the fourth reversible power device 12 generates power; when the second gas is cooled by the multi-stage heat exchange device and migrates from the first gas piston cylinder 7 to the first pressure vessel 1, the second pressure vessel 2 or the seventh pressure vessel 19 in equal volume, the first gas piston rod of the first gas piston cylinder 7 is pushed to move during the migration process, so that the second reversible power device 10 generates power.

[0061] Preferably, the first temperature range and the second temperature range are different, and the first temperature range is lower than the second temperature range.

[0062] In a preferred embodiment, the liquid with the first temperature range can be water at room temperature. Since water at room temperature is easier to obtain and has a lower cost, using water at room temperature as the liquid in the first temperature range can reduce the cost of the system for generating electricity using liquid temperature difference.

[0063] In a preferred embodiment, the liquid with the first temperature range and the liquid with the second temperature range may be made of different substances. For example, the liquid with the second temperature range may be made of high temperature oil or high temperature molten salt, and the liquid with the first temperature range may be made of low temperature oil or water, so as to increase the temperature difference between the first temperature range and the second temperature range, thereby significantly improving the power generation efficiency.

[0064] In a preferred embodiment, the present invention utilizes a liquid temperature difference reversible power generation and heat pump system including: storing a compressed first gas; and utilizing the stored first gas to generate electricity. Therefore, in the present invention utilizes a liquid temperature difference power generation system, a portion of the work done by the isothermal expansion of the high-temperature and high-pressure gas can be used to compress the low-temperature and low-pressure gas in the first pressure vessel, and the compressed gas can be transferred to the compressed gas storage tank, so that the generated electrical energy can be stored in the form of air potential energy of compressed air during the off-peak period of electricity consumption. During peak electricity consumption, the compressed air in the compressed gas storage tank can be transferred to the first pressure vessel, and the work done by the expansion of this part of the compressed air can be used to push the first liquid piston rod to move and generate electricity, thereby achieving peak shaving and valley filling. Of course, the compressed air in the compressed gas storage tank can also be transferred to the second pressure vessel to generate electricity.

[0065] In a preferred embodiment, the liquid temperature difference reversible power generation and heat pump system of the present invention comprises: heating the liquid with the second temperature range in the second liquid pool storing the liquid with the second temperature range to keep the liquid in the second temperature range.

[0066] In a preferred embodiment, the pressure vessel in the present invention is provided with heat insulating materials to insulate it from the outside.

[0067] In a preferred embodiment, the pressure vessel in the present invention can be an internal temperature-controlled liquid piston. The internal temperature-controlled liquid piston refers to controlling the temperature change of the gas during compression or expansion by the liquid inside the liquid piston, and using heat exchange technologies such as gas storage unit technology, water storage unit technology, packed tower technology, plate tower technology, forced liquid circulation technology or heat exchange conduit in the cavity to achieve rapid heat and mass exchange.

[0068] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art who is familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A reversible power generation and heat pump system based on Stirling cycle, comprising: First to fourth pressure vessels (1, 2, 3, 4), first and second hydraulic cylinders (5, 6), first and second gas piston cylinders (7, 8), first to fourth reversible power devices (9, 10, 11, 12), first and second multi-stage heat exchange devices (13, 14); the first and second pressure vessels (1, 2) are configured to store liquid and gas with a first temperature range, and the third and fourth pressure vessels (3, 4) are configured to store liquid and gas with a second temperature range; The first hydraulic cylinder (5) and the first and second pressure vessels (1, 2) form a first liquid piston system, which is used in a low-temperature isothermal compression process. The first piston in the first hydraulic cylinder (5) pushes the liquid in the first temperature range in the first hydraulic cylinder (5) into the first pressure vessel (1) or the second pressure vessel (2) to compress the first gas; the second hydraulic cylinder (6) and the third and fourth pressure vessels (3, 4) form a second liquid piston system, which is used in a high-temperature isothermal expansion process. The second piston of the second hydraulic cylinder (6) moves under the expansion action of the second gas and drives the fourth reversible power device (12) through the second piston rod connected thereto; The low temperature port of the first multi-stage heat exchange device (13) is connected to one of the first and second pressure vessels (1, 2) through valve control, and the high temperature port is connected to one of the third and fourth pressure vessels (3, 4) through valve control; the low temperature port of the second multi-stage heat exchange device (14) is connected to one of the first and second pressure vessels (1, 2) through valve control, and the high temperature port is connected to one of the third and fourth pressure vessels (3, 4) through valve control; The first gas piston cylinder (7) and the second gas piston cylinder (8) are respectively used alternately to drive the isochoric heating process and the isochoric cooling process; the first gas piston cylinder (7) is arranged on a pipeline connecting the low-temperature port of the first multi-stage heat exchange device (13) and the first pressure vessel (1) and the second pressure vessel (2) to control the isochoric migration of the gas, and the second gas piston cylinder (8) is arranged on a pipeline connecting the low-temperature port of the second multi-stage heat exchange device (14) and the first pressure vessel (1) and the second pressure vessel (2) to control the isochoric migration of the gas; The system includes four Stirling cycle processes, namely: In the first process, the low temperature port of the first multi-stage heat exchange device (13) is connected to the first pressure vessel (1) through valve control, and the high temperature port is connected to the fourth pressure vessel (4). The fourth reversible power device (12) controls the movement of the first gas piston rod in the first gas piston cylinder (7) so that the gas in the fourth pressure vessel (4) is isochoricly cooled and migrates to the first pressure vessel (1) through the first multi-stage heat exchange device (13); In the second process, the low temperature port of the first multi-stage heat exchange device (13) is connected to the first pressure vessel (1) through valve control, and the high temperature port is connected to the third pressure vessel (3); the low temperature port of the second multi-stage heat exchange device (14) is connected to the second pressure vessel (2) through valve control, and the high temperature port is connected to the fourth pressure vessel (4); the fourth reversible power device (12) controls the movement of the first gas piston rod in the first gas piston cylinder (7) so that the gas in the third pressure vessel (3) is transferred to the first pressure vessel (1) through isochoric cooling by the first multi-stage heat exchange device (13); the second reversible power device (10) controls the movement of the second gas piston rod in the second gas piston cylinder (8) so that the gas in the second pressure vessel (2) isochoric heating by the second multi-stage heat exchange device (14) and isochoric transferring to the fourth pressure vessel (4); In the third process, the low temperature port of the second multi-stage heat exchange device (14) is connected to the second pressure vessel (2) through valve control, and the high temperature port is connected to the third pressure vessel (3). The second reversible power device (10) controls the movement of the second gas piston rod in the second gas piston cylinder (8) so that the gas in the third pressure vessel (3) is isochorically cooled and migrates to the second pressure vessel (2) through the second multi-stage heat exchange device (14); In the fourth process, the low temperature port of the first multi-stage heat exchange device (13) is connected to the first pressure vessel (1) through valve control, and the high temperature port is connected to the third pressure vessel (3); the low temperature port of the second multi-stage heat exchange device (14) is connected to the second pressure vessel (2) through valve control, and the high temperature port is connected to the fourth pressure vessel (4); the fourth reversible power device (12) controls the movement of the first gas piston rod in the first gas piston cylinder (7) so that the gas in the first pressure vessel (1) is isochorically heated and migrated to the third pressure vessel (3) through the first multi-stage heat exchange device (13); the second reversible power device (10) controls the movement of the second gas piston rod in the second gas piston cylinder (8) so that the gas in the fourth pressure vessel (4) is isochorically cooled and migrated to the second pressure vessel (2) through the second multi-stage heat exchange device (14).

2. A reversible power generation and heat pump system based on Stirling cycle according to claim 1, characterized in that: The first to fourth pressure vessels (1, 2, 3, 4) can be used as gas delivery tanks or gas receiving tanks, wherein liquid and gas with a first temperature range in the first and second pressure vessels (1, 2) and liquid and gas with a second temperature range in the third and fourth pressure vessels (3, 4) can be moved in or out.

3. A reversible power generation and heat pump system based on Stirling cycle according to claim 1, characterized in that: The first to fourth pressure vessels (1, 2, 3, 4) are provided with heat insulation materials to be heat-insulated from the outside.

4. A reversible power generation and heat pump system based on Stirling cycle according to any one of claims 1 to 3, characterized in that: The reversible power devices (9, 10, 11, 12) have both a power generation mode and an electric mode. In the power generation mode, the reversible power devices (9, 11) are driven by the first and second liquid piston rods to generate electricity, and the reversible power devices (10, 12) are driven by the first and second gas piston rods to generate electricity. In the motor mode, the reversible power devices (9, 11) can use electric energy to drive the first and second liquid piston rods to move, and the reversible power devices (10, 12) can use electric energy to drive the first and second gas piston rods to move.

5. A reversible power generation and heat pump system based on Stirling cycle according to claim 1, characterized in that: The first and second multi-stage heat exchange devices (13, 14) use non-simultaneous heat recovery.

6. A reversible power generation and heat pump system based on Stirling cycle according to claim 1, characterized in that: The first and second multi-stage heat exchange devices (13, 14) are composed of a plurality of water storage tanks connected in series, each of which stores relatively full water of different temperatures.

7. A reversible power generation and heat pump system based on Stirling cycle according to claim 1, characterized in that: When the gas needs to be heated up, the gas valve is controlled so that the gas enters through the high-temperature ports of the first and second multi-stage heat exchange devices (13, 14) and is discharged through the low-temperature ports; when the gas needs to be cooled down, the gas valve is controlled so that the gas enters through the low-temperature ports of the first and second multi-stage heat exchange devices (13, 14) and is discharged through the high-temperature ports.

8. A reversible power generation and heat pump system based on Stirling cycle according to claim 6, characterized in that: The first and second multi-stage heat exchange devices (13, 14) are surface heaters or hybrid regenerative heaters.

9. A reversible power generation and heat pump system based on Stirling cycle according to claim 8, characterized in that: The surface heater is a series of water tanks filled with water in a certain temperature range connected in series through exhaust pipes, so that the gas that needs to be heated or cooled does not come into direct contact with the water, and the heat transfer capacity of the metal pipe is used to heat or cool the gas.

10. A reversible power generation and heat pump system based on Stirling cycle according to claim 8, characterized in that: The hybrid heat recovery heater stores water in a temperature range close to that of a full tank in three water tanks, and connects them in series using pipelines for transferring gas, so that the gas that needs to be heated or cooled is in direct contact with the liquid in the water tanks.

11. A reversible power generation and heat pump system based on Stirling cycle according to claim 6, characterized in that: The water storage tanks of the first and second multi-stage heat exchange devices (13, 14) are provided with circulating pumps to pump liquid with a certain temperature range at the bottom of the water storage tank to the top of the water storage tank.

12. The reversible power generation and heat pump system based on Stirling cycle according to claim 1, characterized in that: During the low-temperature isothermal compression process, the first hydraulic cylinder (5), the first pressure vessel (1) and the second pressure vessel (2) all have three states: compression, migration and intake. The intake state of the first pressure vessel (1) spans the first process and the second process, and the intake state of the second pressure vessel (2) spans the third process and the fourth process. During the high-temperature isothermal expansion process, the second hydraulic cylinder (6), the third pressure vessel (3) and the fourth pressure vessel (4) all have three states: migration, expansion and exhaust. The exhaust state of the third pressure vessel (3) spans the second process and the third process, and the exhaust state of the fourth pressure vessel (4) spans the first process and the fourth process. During the isochoric heating process, the first gas piston cylinder (7) and the second gas piston cylinder (8) all have two states: heating and stopping. During the isochoric cooling process, the first gas piston cylinder (7) and the second gas piston cylinder (8) only have one state: cooling.

13. A reversible power generation and heat pump system based on Stirling cycle according to claim 1, characterized in that: The isothermal expansion of the gas in the third pressure vessel (3) or the fourth pressure vessel (4) drives the second temperature liquid in the third pressure vessel (3) or the fourth pressure vessel (4) to flow to the second hydraulic cylinder (6) and drives the second piston rod to move so that the reversible power device (11) generates electricity; after the isothermal expansion of the gas in the third pressure vessel (3) or the fourth pressure vessel (4), when the gas migrates from the third pressure vessel (3) or the fourth pressure vessel (4) to the first pressure vessel (1) or the second pressure vessel (2) by the same volume through the second gas piston cylinder (8), the gas drives the second gas piston rod so that the reversible power device (12) generates electricity.

14. The reversible power generation and heat pump system based on Stirling cycle according to claim 1, characterized in that: During the operation of the heat pump, the first liquid piston system is used for a low-temperature isothermal expansion process. When the gas in the first or second pressure vessel is isothermally expanded at low temperature, the first temperature liquid flows from the first pressure vessel (1) or the second pressure vessel (2) to the first hydraulic cylinder (5), driving the first piston to move and pushing the reversible power device (9) to generate electricity; the second liquid piston system is used for a high-temperature isothermal compression process. After the gas in the third pressure vessel (3) or the fourth pressure vessel (4) is isothermally compressed, when the gas is transferred from the third pressure vessel (3) or the fourth pressure vessel (4) to the first pressure vessel (1) or the second pressure vessel (2) in equal volume through the second gas piston cylinder (8), the second gas piston rod is pushed to push the reversible power device (12) to generate electricity; the first gas piston cylinder (7) and the second gas piston cylinder (8) are alternately used for driving the isochoric heating process and the isochoric cooling process.

15. The reversible power generation and heat pump system based on Stirling cycle according to claim 1, characterized in that: The system further comprises a fifth pressure container (15) and a sixth pressure container (16); the fifth pressure container (15) is connected to the first hydraulic cylinder (5) at the bottom, and is connected to one of the first gas piston cylinder (7) and the second gas piston cylinder (8) at the top through a gas valve control; the sixth pressure container (16) is connected to the second hydraulic cylinder (6) at the bottom, and is connected to one of the first gas piston cylinder (7) and the second gas piston cylinder (8) at the top through a gas valve control; the fifth pressure container (15) stores liquid in a first temperature range, and the sixth pressure container (16) stores liquid in a second temperature range.

16. The reversible power generation and heat pump system based on Stirling cycle according to claim 1, characterized in that: The system further comprises a third hydraulic cylinder (17), a fourth hydraulic cylinder (18), a seventh pressure vessel (19), and an eighth pressure vessel (20); the first hydraulic cylinder (5) is connected in parallel with the third hydraulic cylinder (17), and the second hydraulic cylinder (6) is connected in parallel with the fourth hydraulic cylinder.

17. A reversible power generation and heat pump system based on Stirling cycle according to any one of claims 1, 2 or 12, characterized in that: The first temperature range is lower than the second temperature range.

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