Polygeneration energy storage system and method for hydrogen production by coupling solar energy with LNG (Liquefied Natural Gas) cold energy

Abstract

The invention relates to the technical field of solar heat utilization, and discloses a solar energy coupling LNG cold energy hydrogen production poly-generation energy storage system and method, and the system comprises a solar photovoltaic unit, a water electrolysis hydrogen production unit, a refrigeration and heating unit and a heat pump electricity storage unit; the solar photovoltaic unit comprises an electric energy part and a photo-thermal part, an outlet of the electric energy part is connected with the water electrolysis hydrogen production unit, and water electrolysis hydrogen production and storage are driven through electric quantity; the surplus electric quantity of the electric energy part is connected with the heat pump electricity storage unit to store the electric quantity; a first outlet of the photo-thermal part is connected with the refrigerating and heating unit, and an outlet of the refrigerating and heating unit is connected with the heat pump electricity storage unit, provides external heat energy for the heat pump electricity storage unit and is connected with the solar photovoltaic unit through the heat pump electricity storage unit. Combined supply of multiple energy products is achieved, the comprehensive utilization efficiency of multiple energy sources is improved, irreversible loss in the process is reduced, and the energy storage efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of solar thermal utilization, and in particular to a multi-generation energy storage system and method for producing hydrogen by coupling solar energy with LNG cold energy. Background Art

[0002] As a clean, universal and "unlimited" renewable energy source, the development of solar energy is of great significance to my country's construction of an efficient, clean and low-carbon energy supply system; LNG is environmentally friendly, non-toxic and inexpensive. Utilizing the cold energy of its gasification process can help improve energy utilization efficiency and promote the sustainable development of the ecological environment and the economy.

[0003] Under the established dual-carbon strategic goals, multi-energy-driven cogeneration technology has received increasing attention. The energy system of green electricity hydrogen production coupled with cogeneration can provide abundant energy products, and its development has the functions of enhancing energy supply capacity, saving resources and improving the environment. As an important part of the current power system regulation, energy storage plays a very positive role in improving the continuous energy supply of renewable energy. Heat pump energy storage technology, as a representative energy storage technology, can store electrical energy as thermal energy and convert it back to electrical energy during peak electricity consumption. The characteristics of this technology are long service life, high energy density and relatively low maintenance cost. It is a very promising energy storage system.

[0004] In recent years, many scholars at home and abroad have conducted extensive research on the polygeneration technology driven by multi-energy complementarity, which also covers energy forms such as solar energy and LNG. However, the research found that in the design process of the energy system, how to effectively develop various forms of energy, realize the joint supply of multiple energy products, improve the comprehensive utilization efficiency of multiple energy sources, and reduce the irreversible losses of the process still needs in-depth research. Therefore, based on the good development potential of polygeneration technology driven by multi-energy complementarity in the energy field, how to construct an appropriate cycle configuration to efficiently develop solar energy and couple the use of LNG cold energy has become a technical problem that researchers in this field need to solve urgently. Summary of the invention

[0005] The present invention aims to provide a multi-generation energy storage system and method for producing hydrogen by coupling solar energy with LNG cold energy, so as to effectively develop various forms of energy, realize the joint supply of various energy products, improve the comprehensive utilization efficiency of multiple energy sources, and reduce the irreversible losses of the process.

[0006] To achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a solar energy coupled LNG cold energy hydrogen production polygeneration energy storage system and method. This scheme improves energy storage efficiency and effectively improves energy utilization efficiency. The system includes a solar photovoltaic unit, a water electrolysis hydrogen production unit, a refrigeration and heating unit, and a heat pump power storage unit;

[0007] The solar photovoltaic unit includes an electric energy part and a photothermal part. The outlet of the electric energy part is connected to the water electrolysis hydrogen production unit, and the electric energy drives the water electrolysis to produce hydrogen and store it; the surplus electric energy of the electric energy part is connected to the heat pump power storage unit to store the electric energy; the first outlet of the photothermal part is connected to the refrigeration and heating unit, and the outlet of the refrigeration and heating unit is connected to the heat pump power storage unit to provide external heat energy for the heat pump power storage unit, and is connected to the solar photovoltaic unit via the heat pump power storage unit;

[0008] It also includes an LNG cold energy unit, which is connected to the heat pump power storage unit. The LNG cold energy unit converts the thermal energy in the heat pump power storage unit into electrical energy, and converts the LNG in the LNG cold energy unit into NG output.

[0009] The principles and advantages of this solution are:

[0010] Generally speaking, in the utilization of solar energy, using solar energy to produce hydrogen and peak load for power generation is a common method. The energy conversion efficiency of solar energy to produce hydrogen is relatively high, but due to equipment limitations, the energy conversion efficiency of existing solar power generation devices is very low, so it can only be used as an auxiliary means in the field of power generation. Actual research has found that the use of multi-module cogeneration can effectively improve the energy utilization rate of solar energy.

[0011] Applying solar energy to the LNG gasification process can effectively improve the energy utilization efficiency of solar energy. The heat energy generated by solar energy can directly serve as the heat source for LNG gasification, while the large amount of cold energy generated by LNG gasification can achieve more efficient power generation.

[0012] Therefore, this scheme adopts solar photovoltaic / thermal energy devices to directly convert solar energy into electrical energy and thermal energy, wherein the electrical energy can directly drive the proton exchange membrane to electrolyze water to produce hydrogen, and the surplus electricity will be stored through the heat pump power storage cycle; wherein the thermal energy can drive the absorption refrigeration cycle to generate cold or provide heat through plate exchange, and at the same time, the heat pump power storage cycle is connected in series as an external heat source, thereby improving the energy storage efficiency and effectively improving the energy utilization efficiency.

[0013] Among them, the refrigeration and heating circulation unit and the heat pump power storage unit are directly connected together through a three-way valve and a heat exchanger. The intermediate medium heat transfer oil of the refrigeration and heating unit serves as the heat source of the heat pump power storage unit. The heat pump power storage unit and the LNG cold energy unit are directly connected, thereby realizing the interconnection and utilization of multiple energy sources, improving energy utilization, and reducing energy loss.

[0014] In addition, the existing LNG cold energy power generation system is generally an independent system, and the power generation efficiency is closely related to the temperature of the heat source. In this scheme, solar energy is coupled to the LNG cold energy power generation system. On the one hand, the temperature of the heat source is increased without increasing power consumption, thereby increasing the power generation efficiency; on the other hand, compared with the independent operation of the two systems, the number of equipment in the combined system is less, thus reducing the device cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic structural diagram of the polygeneration and energy storage system for producing hydrogen by coupling solar energy with LNG cold energy according to the present invention.

[0016] Figure 2 It is a schematic flow chart of the polygeneration and energy storage method of producing hydrogen by coupling solar energy with LNG cold energy according to the present invention. DETAILED DESCRIPTION

[0017] The following is further described in detail through specific implementation methods:

[0018] Reference numerals in the drawings of the specification include: solar photovoltaic unit 01;

[0019] Water electrolysis hydrogen production unit: water heater 02, proton exchange membrane electrolyzer 03, oxygen separator 04, hydrogen storage tank 05, first three-way valve 06;

[0020] Refrigeration and heating unit: generator 07, first condenser 08, first throttle valve 09, evaporator 10, absorber 11, first pump 12, solution heat exchanger 13, second throttle valve 14, second three-way valve 15, first heat exchanger 16;

[0021] Heat pump power storage unit: heat pump circulation evaporator 17, compressor 18, second condenser 19, third throttle valve 20, high temperature storage tank 21, second pump 22, low temperature storage tank 23, third pump 24, power generation circulation evaporator 25, turbine 26, power generation circulation condenser 27, working fluid pump 28;

[0022] LNG cold energy unit: LNG cold energy storage tank 29, booster pump 30, second heat exchanger 31, LNG turbine 32.

[0023] Embodiment 1

[0024] This embodiment is basically as shown in the attached Figure 1As shown, the solar energy coupled LNG cold energy hydrogen production multi-generation energy storage system and method uses solar photovoltaic / thermal energy devices to directly convert solar energy into electrical energy and thermal energy, wherein the electrical energy can directly drive the proton exchange membrane electrolyzer 03 to electrolyze water to produce hydrogen, and the surplus electricity will be stored through the heat pump power storage unit cycle; wherein the thermal energy can drive the refrigeration and heating unit cycle to generate cold or heat through plate exchange, and at the same time connect the heat pump power storage cycle in series as an external heat source, so as to improve the energy storage efficiency. The system includes a solar photovoltaic unit, a water electrolysis hydrogen production unit, a refrigeration and heating unit, a heat pump power storage unit and an LNG cold energy unit.

[0025] Solar photovoltaic unit 01 is a solar photovoltaic / thermal device. After absorbing sunlight and converting it, it can include an electrical energy part and a photothermal part. The outlet of the electrical energy part is connected to the water electrolysis hydrogen production unit, and the electricity is used to drive the water electrolysis hydrogen production and storage. The surplus electricity of the electrical energy part is connected to the heat pump power storage unit to store the electricity.

[0026] The first outlet of the photothermal part is connected to the refrigeration and heating unit, and the outlet of the refrigeration and heating unit is connected to the heat pump power storage unit to provide external heat energy for the heat pump power storage unit, and is connected to the heat pump power storage unit and the solar photovoltaic unit via the heat pump power storage unit. The LNG cold energy unit is connected to the heat pump power storage unit, and the heat energy in the heat pump power storage unit is converted into electrical energy through the LNG cold energy unit, and the LNG in the LNG cold energy unit is converted into NG output.

[0027] In this embodiment, as shown in the attached Figure 1 As shown, the solar photovoltaic unit is connected to the proton exchange membrane electrolyzer 03, and directly drives the proton exchange membrane electrolyzer 03 to electrolyze water to produce hydrogen. The water electrolysis hydrogen production unit includes a water heater 02, the outlet of the water heater 02 is connected to the inlet of the proton exchange membrane electrolyzer 03; the oxygen outlet of the proton exchange membrane electrolyzer 03 is connected to the inlet of the oxygen separator 04, and the hydrogen outlet of the proton exchange membrane electrolyzer 03 is connected to the inlet of the hydrogen storage tank 05.

[0028] The water outlet of the oxygen separator 04 is connected to the inlet of the proton exchange membrane electrolyzer 03 after merging with the outlet flow of the water heater 02, and the oxygen outlet of the oxygen separator 04 is connected to other equipment.

[0029] The refrigeration and heating unit includes a refrigeration part and a heating part. Among them, the refrigeration part includes a generator 07, and the photothermal part of the solar photovoltaic unit is connected to the high temperature side inlet of the generator 07 through the first three-way valve 06. The first low temperature side outlet of the generator 07 is connected to the high temperature side inlet of the first condenser 08. The high temperature side outlet of the first condenser 08 is connected to the inlet of the first throttle valve 09, and the outlet of the first throttle valve 09 is connected to the low temperature side inlet of the evaporator 10. The low temperature side outlet of the evaporator 10 is connected to the first high temperature side inlet of the absorber 11, and the high temperature side outlet of the absorber 11 is connected to the inlet of the first pump 12, and the outlet of the first pump 12 is connected to the low temperature side inlet of the solution heat exchanger 13, and the low temperature side outlet of the solution heat exchanger 13 is connected to the low temperature side inlet of the generator 07.

[0030] At the same time, the second low-temperature side outlet of the generator 07 is connected to the high-temperature side inlet of the solution heat exchanger 13, the high-temperature side outlet of the solution heat exchanger 13 is connected to the inlet of the second throttle valve 14, and the outlet of the second throttle valve 14 is connected to the second high-temperature side inlet of the absorber 11.

[0031] The heating part includes a second three-way valve 15 connected to the high-temperature side outlet of the generator 07, the first outlet of the second three-way valve 15 is connected to the high-temperature side inlet of the first heat exchanger 16, the high-temperature side inlet of the first heat exchanger 16 is connected to the first inlet of the second three-way valve 15, the second outlet of the second three-way valve 15 is connected to the heat pump power storage unit, and is connected to the inlet of the photothermal part through the heat pump power storage unit.

[0032] The heat pump power storage unit includes a heat pump circulation evaporator 17, the low-temperature side outlet of the heat pump circulation evaporator 17 is connected to the inlet of a compressor 18, the compressor 18 is directly driven by the surplus electricity of the electric energy part, the outlet of the compressor 18 is connected to the high-temperature side inlet of the second condenser 19, the high-temperature side outlet of the second condenser 19 is connected to the inlet of the third throttle valve 20, and the outlet of the third throttle valve 20 is connected to the low-temperature side inlet of the heat pump circulation evaporator 17.

[0033] At the same time, the low-temperature side outlet of the second condenser 19 is connected to the inlet of the high-temperature storage tank 21, the outlet of the high-temperature storage tank 21 is connected to the inlet of the second pump 22, the outlet of the second pump 22 is connected to the high-temperature side inlet of the power generation circulation evaporator 25, the high-temperature side outlet of the power generation circulation evaporator 25 is connected to the inlet of the low-temperature storage tank 23, the outlet of the low-temperature storage tank 23 is connected to the inlet of the third pump 24, and the outlet of the third pump 24 is connected to the low-temperature side inlet of the second condenser 19.

[0034] The low-temperature side outlet of the power generation cycle evaporator 25 is connected to the inlet of the turbine 26 , the outlet of the turbine 26 is connected to the high-temperature side inlet of the power generation cycle condenser 27 , the high-temperature side outlet of the power generation cycle condenser 27 is connected to the inlet of the working fluid pump 28 , and the outlet of the working fluid pump 28 is connected to the low-temperature side inlet of the power generation cycle evaporator 25 .

[0035] The LNG cold energy unit includes an LNG cold energy storage tank 29, the outlet of the LNG cold energy storage tank 29 is connected to the inlet of the booster pump 30, the outlet of the booster pump 30 is connected to the low-temperature side inlet of the power generation cycle condenser 27, the low-temperature side outlet of the power generation cycle condenser 27 is connected to the low-temperature side inlet of the second heat exchanger 31, the low-temperature side outlet of the second heat exchanger 31 is connected to the inlet of the LNG turbine 32, the outlet of the LNG turbine 32 is connected to the LNG receiving station equipment, driving the LNG turbine 32 to generate electricity, converting it into NG and entering the receiving station or related equipment, finally completing the entire system cycle.

[0036] This scheme adopts technologies such as solar photovoltaic / thermal, water electrolysis hydrogen production, absorption refrigeration, heat pump power storage and LNG power generation to construct a multi-generation-energy storage cycle coupled with multiple energy sources. The use of solar photovoltaic / thermal technology can efficiently utilize solar energy resources, realize hydrogen production and storage, and store surplus electricity at the same time, effectively improving energy utilization efficiency; in response to the problem of variable energy demand on the user side, light-thermal driven refrigeration and heating can effectively provide various forms of energy, and at the same time, the tail end heat energy is supplied to the heat pump power storage unit as input, realizing the cascade utilization of energy, and further effectively improving the overall energy utilization efficiency of the system; the LNG part is used as a cold source on the power generation side of the heat pump power storage unit, effectively reducing the operating temperature zone of the entire heat pump power storage unit, and coupling LNG cold energy further enriches the supply of system energy products and reduces the irreversible loss of the LNG gasification process. The hydrogen production multi-generation-energy storage system driven by solar energy and coupled with LNG cold energy of the present invention has high energy utilization efficiency and energy product supply, which is of great significance to the development and utilization of multi-energy coupling.

[0037] In the prior art, although solar power generation technology has made significant progress, it is limited by the equipment and technology limitations of solar power generation devices, resulting in low efficiency in the conversion of existing solar energy. Therefore, it can generally only be used as an auxiliary means in the field of solar power generation. In order to improve the conversion efficiency of solar energy, the current main approach is to set up separate energy conversion modules for different power generation needs and application scenarios to improve the utilization rate of solar energy. However, the separately designed modules need to be equipped with corresponding operating equipment, which makes them more expensive, and the other energy generated needs to be converted or stored separately, resulting in resource loss and waste.

[0038] Even if some energy sources can be used in combination, they are based on limited scenarios, such as combining the hydrogen production part to improve the comprehensive utilization rate of solar energy in different fields as much as possible, but its utilization efficiency has always been difficult to break through. At the same time, since LNG cold energy power generation involves multiple technical links, these links require a high degree of technical integration and coordination. Therefore, the general LNG cold energy power generation system is an independent system to better adapt to the characteristics of this cold energy and improve the utilization and recovery efficiency. Under the premise of improving efficiency, it is generally not considered to be used in combination. This solution adopts a multi-module co-production method to further break through the bottleneck of solar energy utilization efficiency, while overcoming the inherent LNG cold energy power generation system model, applying solar energy to the gasification process of LNG, directly serving as a heat source for LNG gasification, and making full use of the cold energy generated by LNG to achieve more efficient cycle power generation and improve the comprehensive utilization efficiency of solar energy.

[0039] Embodiment 2

[0040] In this embodiment, a method for producing hydrogen from solar energy coupled with LNG cold energy is provided, which is applied to the polygeneration and storage system for producing hydrogen from solar energy coupled with LNG cold energy in the first embodiment, as shown in the attached Figure 2 As shown, including:

[0041] Solar energy conversion and storage: The solar photovoltaic unit absorbs solar energy, generates electricity to drive the water electrolysis hydrogen production unit to produce and store hydrogen. At the same time, the photothermal part drives the refrigeration and heating unit and provides heat energy for the heat pump power storage unit.

[0042] First, the solar photovoltaic unit, i.e., the solar photovoltaic / thermal collection device, absorbs sunlight from the outside. The electricity generated by the photovoltaic part directly drives the electrolysis of water to produce hydrogen. The water is heated in the water heater 02 and then enters the proton exchange membrane electrolyzer 03 to be electrolyzed into hydrogen and oxygen. The hydrogen is directly stored in the hydrogen storage tank 05, and the oxygen part flows through the oxygen separator 04, wherein the water part will be recycled into the proton exchange membrane electrolyzer 03, and the oxygen part will be separated from the oxygen separator 04 and used for other purposes.

[0043] The cooling and heating unit driven by solar thermal is a closed cycle. The heat transfer oil heated by solar energy flows out of the solar photovoltaic unit 01, and is split through the first three-way valve 06. Part of the heat energy drives the absorption refrigeration cycle to provide cooling; the other flow directly passes through the first heat exchanger 16 to provide heating. The two flows converge at the second three-way valve 15, and then serve as a heat source to provide external heat energy for the energy storage cycle of the heat pump power storage unit, and finally return to the solar photovoltaic unit 01 after the heat exchange process of the heat pump cycle evaporator 17.

[0044] Thermal energy storage and conversion: the heat pump power storage unit converts surplus electricity into thermal energy and stores it through an intermediate heat storage medium. When needed, the heat is released and converted into electrical energy.

[0045] In this embodiment, the conversion of electrical energy into thermal energy is as follows: the heat pump power storage unit stores the surplus electricity of the electrical energy part, and this part of electricity directly drives the compressor 18 to operate, and further increase the pressure of the organic working fluid heated by the heat pump circulation evaporator 17, and enters the second condenser 19 after being pressurized by the compressor 18, and transfers the heat energy to the intermediate heat storage medium. The organic working fluid after releasing the heat becomes a high-pressure and low-temperature state, and then reduces the pressure through the third throttle valve 20 and flows back to the heat pump circulation evaporator 17, thereby realizing the conversion of electrical energy into thermal energy.

[0046] The intermediate heat storage medium comes out of the low temperature storage tank 23, is pressurized by the third pump 24, and enters the second condenser 19 to be heated, and then the high temperature medium enters the high temperature storage tank 21 to be stored. In the energy release stage, the energy storage medium flows out of the high temperature storage tank 21, is pressurized by the second pump 22, enters the power generation cycle evaporator 25 to release heat energy, and then flows back to the low temperature storage tank 23. In this embodiment, the intermediate heat storage medium can generally be water.

[0047] The conversion of heat energy into electrical energy is as follows: the organic working fluid in the power generation cycle is heated to a high temperature and high pressure state in the power generation cycle evaporator 25, enters the turbine 26 to generate mechanical work and drives the generator to supply power, and the exhaust gas at the outlet of the turbine 26 is cooled by LNG in the power generation cycle condenser 27, and then pressurized by the working fluid pump 28 and returns to the power generation cycle evaporator 25, thereby realizing the conversion of heat energy into electrical energy.

[0048] LNG utilization and power generation, through the LNG cold energy unit to absorb heat in the system and generate electricity, convert LNG into NG and enter the receiving station equipment, completing the system cycle.

[0049] LNG is pumped out from the LNG cold energy storage tank 29 by the booster pump 30, absorbs part of the heat in the power generation cycle condenser 27, and then absorbs heat in the second heat exchanger 31, and finally drives the LNG turbine 32 to generate electricity, and is converted into NG and enters the receiving station or related equipment, finally completing the entire system cycle.

[0050] This solution can efficiently utilize solar energy and LNG cold energy resources, realize the cogeneration of cold, heat, hydrogen and electricity and energy storage, complete the comprehensive and cascade utilization of energy, and effectively improve the overall energy utilization efficiency of the system; coupling LNG cold energy further enriches the supply of system energy products and reduces the irreversible loss of LNG gasification process. This solution is driven by solar energy and coupled with LNG cold energy. The hydrogen production polygeneration-energy storage system has high energy utilization efficiency and energy product supply, which is of great significance to the development and utilization of multi-energy coupling.

[0051] The above is only an embodiment of the present invention, and the common knowledge such as the known specific technical solutions and / or characteristics in the solution is not described in detail here. It should be pointed out that for those skilled in the art, without departing from the technical solution of the present invention, several modifications and improvements can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A solar energy coupled LNG cold energy hydrogen production and storage system, characterized by: It includes solar photovoltaic unit, water electrolysis hydrogen production unit, refrigeration and heating unit and heat pump power storage unit; The solar photovoltaic unit includes an electric energy part and a photothermal part. The outlet of the electric energy part is connected to the water electrolysis hydrogen production unit, and the electric energy drives the water electrolysis to produce hydrogen and store it; the surplus electric energy of the electric energy part is connected to the heat pump power storage unit to store the electric energy; the first outlet of the photothermal part is connected to the refrigeration and heating unit, and the outlet of the refrigeration and heating unit is connected to the heat pump power storage unit to provide external heat energy for the heat pump power storage unit, and is connected to the solar photovoltaic unit via the heat pump power storage unit; It also includes an LNG cold energy unit, which is connected to the heat pump power storage unit. The LNG cold energy unit converts the thermal energy in the heat pump power storage unit into electrical energy, and converts the LNG in the LNG cold energy unit into NG output.

2. The solar energy coupled LNG cold energy hydrogen production and storage system according to claim 1 is characterized by: The water electrolysis hydrogen production unit comprises a water heater, the outlet of the water heater is connected to the inlet of the proton exchange membrane electrolyzer; the oxygen outlet of the proton exchange membrane electrolyzer is connected to the inlet of the oxygen separator, the water outlet of the oxygen separator is connected to the inlet of the proton exchange membrane electrolyzer after merging with the outlet flow of the water heater; the oxygen outlet of the oxygen separator is connected to other equipment; the hydrogen outlet of the proton exchange membrane electrolyzer is connected to the inlet of the hydrogen storage tank; the solar photovoltaic unit is connected to the proton exchange membrane electrolyzer, and drives the proton exchange membrane electrolyzer to electrolyze water to produce hydrogen.

3. The solar energy coupled LNG cold energy hydrogen production and storage system according to claim 1 is characterized by: The refrigeration and heating unit includes a refrigeration part and a heating part; the refrigeration part includes a generator, and the photothermal part of the solar photovoltaic unit is connected to the high-temperature side inlet of the generator through a first three-way valve; the first low-temperature side outlet of the generator is connected to the high-temperature side inlet of the first condenser, the high-temperature side outlet of the first condenser is connected to the inlet of the first throttle valve, the outlet of the first throttle valve is connected to the low-temperature side inlet of the evaporator, the low-temperature side outlet of the evaporator is connected to the first high-temperature side inlet of the absorber, the high-temperature side outlet of the absorber is connected to the inlet of the first pump, the outlet of the first pump is connected to the low-temperature side inlet of the solution heat exchanger, and the low-temperature side outlet of the solution heat exchanger is connected to the low-temperature side inlet of the generator; the second low-temperature side outlet of the generator is connected to the high-temperature side inlet of the solution heat exchanger, the high-temperature side outlet of the solution heat exchanger is connected to the inlet of the second throttle valve, and the outlet of the second throttle valve is connected to the second high-temperature side inlet of the absorber.

4. The solar energy coupled LNG cold energy hydrogen production and storage system according to claim 3 is characterized by: The heat supply part includes a second three-way valve connected to the high-temperature side outlet of the generator, the first outlet of the second three-way valve is connected to the high-temperature side inlet of the first heat exchanger, the high-temperature side inlet of the first heat exchanger is connected to the first inlet of the second three-way valve, the second outlet of the second three-way valve is connected to the heat pump power storage unit, and is connected to the inlet of the photothermal part through the heat pump power storage unit.

5. The solar energy coupled LNG cold energy hydrogen production and storage system according to claim 1 is characterized by: The heat pump power storage unit includes a heat pump circulation evaporator, the low-temperature side outlet of the heat pump circulation evaporator is connected to the inlet of the compressor, the compressor is driven by the surplus power of the electric energy part, the outlet of the compressor is connected to the high-temperature side inlet of the second condenser, the high-temperature side outlet of the second condenser is connected to the inlet of the third throttle valve, and the outlet of the third throttle valve is connected to the low-temperature side inlet of the heat pump circulation evaporator.

6. The solar energy coupled LNG cold energy hydrogen production and storage system according to claim 5 is characterized by: It also includes a low-temperature side outlet of the second condenser connected to the inlet of the high-temperature storage tank, the outlet of the high-temperature storage tank is connected to the inlet of the second pump, the outlet of the second pump is connected to the high-temperature side inlet of the power generation cycle evaporator, the high-temperature side outlet of the power generation cycle evaporator is connected to the inlet of the low-temperature storage tank, the outlet of the low-temperature storage tank is connected to the inlet of the third pump, and the outlet of the third pump is connected to the low-temperature side inlet of the second condenser.

7. The solar energy coupled LNG cold energy hydrogen production and storage system according to claim 6 is characterized by: It also includes a low-temperature side outlet of the power generation cycle evaporator connected to the inlet of the turbine, the outlet of the turbine connected to the high-temperature side inlet of the power generation cycle condenser, the high-temperature side outlet of the power generation cycle condenser connected to the inlet of the working fluid pump, and the outlet of the working fluid pump connected to the low-temperature side inlet of the power generation cycle evaporator.

8. The solar energy coupled LNG cold energy hydrogen production and storage system according to claim 7 is characterized by: The LNG cold energy unit includes an LNG cold energy storage tank, the outlet of the LNG cold energy storage tank is connected to the inlet of the booster pump, the outlet of the booster pump is connected to the low-temperature side inlet of the power generation cycle condenser, the low-temperature side outlet of the power generation cycle condenser is connected to the low-temperature side inlet of the second heat exchanger, the low-temperature side outlet of the second heat exchanger is connected to the inlet of the LNG turbine, and the outlet of the LNG turbine is connected to the LNG receiving station equipment.

9. A method for producing hydrogen from solar energy coupled with LNG cold energy and storing energy, characterized in that: The polygeneration energy storage system for producing hydrogen by solar energy coupled with LNG cold energy as described in any one of claims 1 to 8 comprises: Solar energy conversion and storage: The solar photovoltaic unit absorbs solar energy, generates electricity to drive the water electrolysis hydrogen production unit to produce and store hydrogen. At the same time, the photothermal part drives the refrigeration and heating unit and provides heat energy for the heat pump power storage unit. Thermal energy storage and conversion: the heat pump power storage unit converts the surplus electricity into thermal energy and stores it through an intermediate heat storage medium. When needed, the heat is released and converted into electrical energy. LNG utilization and power generation, through the LNG cold energy unit to absorb heat in the system and generate electricity, convert LNG into NG and enter the receiving station equipment, completing the system cycle.

10. The method for producing hydrogen from solar energy coupled with LNG cold energy and storing energy according to claim 9, characterized in that: In thermal energy storage and conversion, The conversion of electrical energy into thermal energy is as follows: the surplus electricity of the electrical energy part drives the compressor to operate, further increasing the pressure of the organic working fluid heated by the heat pump circulation evaporator, and then entering the second condenser after being pressurized by the compressor, transferring the heat energy to the intermediate heat storage medium, and the organic working fluid after releasing the heat becomes a high-pressure and low-temperature state, and then passes through the third throttle valve to reduce the pressure and flow back to the heat pump circulation evaporator; The conversion of heat energy into electrical energy is as follows: the organic working fluid is heated to a high temperature and high pressure state in the power generation cycle evaporator, enters the turbine to generate mechanical work and drives the generator to provide power; the exhaust gas at the turbine outlet is cooled by LNG in the power generation cycle condenser, and then pressurized by the working fluid pump and returns to the power generation cycle evaporator.

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