An ORC system driven by phase change energy storage and LNG cold energy

Abstract

This invention discloses an ORC system driven by phase change energy storage and LNG cold energy. A heat exchanger is installed in the LNG cold energy utilization unit. Both the solar heating unit and the organic Rankine cycle unit are connected to the heat exchanger in the LNG cold energy utilization unit. The solar heating unit and the organic Rankine cycle unit are interconnected. All three units are connected to the energy storage structure unit. The solar heating unit and the LNG cold energy utilization unit provide heat and cold sources to the organic Rankine cycle unit, respectively. The organic Rankine cycle unit stores the working fluid. The expander, working fluid pump, and LNG cold energy utilization unit are all connected to the condenser. This invention, based on phase change energy storage and LNG cold energy drive, optimizes the heating system and fluid thermal storage equipment, and achieves full utilization of LNG cold energy, thereby improving the system's flexibility and stability and significantly increasing energy utilization efficiency.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of energy saving of comprehensive energy system, and particularly relates to a phase change energy storage and LNG cold energy driven ORC system. BACKGROUND

[0002] With the sharp increase in the consumption of fossil energy, energy shortage has become one of the common problems faced by mankind, and thus renewable energy needs to be developed vigorously. As a kind of abundant renewable energy, solar energy has broad application prospects. Since solar energy can be directly developed and utilized, more and more heating systems adopt solar energy as the energy supply energy. However, due to the influence of natural conditions such as day and night, season, weather and the like, the utilization rate of solar heating is not high, and the system is not stable enough, and thus the design of the solar heating system needs to be optimized and improved.

[0003] With the rapid development of cold chain logistics, data centers and the like, the demand for cold energy is also increasing. As a new cold source, LNG cold energy can meet the diversified demand of the market. In the LNG liquefaction process, the temperature of LNG is about -162 DEG C, and this low-temperature characteristic makes LNG release cold energy, which can be used for various cooling and refrigeration applications. Utilizing the cold energy of LNG can effectively improve the energy utilization efficiency and reduce the cost. However, in the conventional cold energy storage, problems such as small heat storage capacity, large heat release temperature fluctuation and slow reaction speed often occur, which leads to the loss of LNG cold energy and low utilization efficiency, and thus the heat storage unit needs to be optimized and improved. SUMMARY

[0004] In order to solve the problems in the background art, the purpose of the present application is to provide a phase change energy storage and LNG cold energy driven ORC (organic Rankine cycle) system, so as to solve the problems of small heat storage capacity, large volume, large thermal inertia and unstable output of the heating system, and make full use of LNG cold energy, so as to greatly improve the energy utilization rate.

[0005] The technical scheme adopted by the present application is as follows:

[0006] The system comprises a solar heating unit, an energy storage structure unit, an LNG cold energy utilization unit and an organic Rankine cycle unit. The LNG cold energy utilization unit is provided with a heat exchanger. The solar heating unit and the organic Rankine cycle unit are connected with the heat exchanger in the LNG cold energy utilization unit. The solar heating unit and the organic Rankine cycle unit are connected. The solar heating unit, the LNG cold energy utilization unit and the organic Rankine cycle unit are connected with the energy storage structure unit. The solar heating unit and the LNG cold energy utilization unit provide heat source and cold source for the organic Rankine cycle unit respectively. The organic Rankine cycle unit stores working medium.

[0007] The solar heat supply unit comprises a solar heat collector, a heat storage heat exchanger and a heat source pump, one end of the solar heat collector and the heat storage heat exchanger are connected, the other end of the heat storage heat exchanger is connected with a phase change heat accumulator in the energy storage structure unit, the outlet of the heat storage heat exchanger is connected with the inlet of the heat source pump, the outlet of the heat source pump is connected with an organic Rankine cycle unit, the inlet of the heat storage heat exchanger is connected with an LNG cold energy utilization unit.

[0008] The organic Rankine cycle unit comprises an evaporator, a first throttling valve, a first generator, a first expander, a working medium pump and a condenser; one inlet of the evaporator is connected with the heat source pump in the solar heat supply unit, the other inlet of the evaporator is connected with the outlet of the working medium pump, one outlet of the evaporator is connected with the LNG cold energy utilization unit through the first throttling valve, the other outlet of the evaporator is connected with the inlet of the first expander, the first expander is connected with the first generator, the first generator is connected with the phase change heat accumulator in the energy storage structure unit, the outlet of the first expander is connected with the inlet of the condenser, the outlet of the condenser is connected with the inlet of the working medium pump, and the condenser is also connected with the LNG cold energy utilization unit.

[0009] The LNG cold energy utilization unit comprises a liquefied natural gas storage tank, a liquefied natural gas pump, a second throttling valve, a heat exchanger, a second expander, a second generator, a cold storage heat exchanger and a natural gas supply device.

[0010] The outlet of the liquefied natural gas storage tank is connected with the inlet of the liquefied natural gas pump, the outlet of the liquefied natural gas pump is connected with the inlet of the second throttling valve, the outlet of the second throttling valve is connected with the inlet of the heat exchanger through the condenser in the organic Rankine cycle unit, the heat exchanger is connected with the outlet of the evaporator in the organic Rankine cycle unit through the first throttling valve in the organic Rankine cycle unit, the heat exchanger is connected with the inlet of the second expander, the heat exchanger is connected with the heat storage heat exchanger in the solar heat supply unit, the second expander is connected with the second generator, the outlet of the second expander is connected with the inlet of the cold storage heat exchanger, the outlet of the cold storage heat exchanger is connected with the phase change cold accumulator in the energy storage structure unit, and the cold storage heat exchanger is also connected with the natural gas supply device, and the natural gas supply device is used for providing liquefied natural gas for users.

[0011] The energy storage structure unit comprises a phase change heat accumulator and a phase change cold accumulator; one end of the phase change heat accumulator is connected with the heat storage heat exchanger in the solar heat supply unit, the other end of the phase change heat accumulator is connected with the first generator in the organic Rankine cycle unit, and the phase change cold accumulator is connected with the cold storage heat exchanger in the LNG cold energy utilization unit.

[0012] The solar heat collector and the heat storage heat exchanger in the solar heat supply unit are connected to form a heat collection circulation pipeline, and the outlet of the heat storage heat exchanger, the evaporator, the heat exchanger, and the inlet of the heat storage heat exchanger are sequentially connected to form a heat supply circulation pipeline, and the heat collection circulation pipeline and the heat supply circulation pipeline both store heat exchange working medium, and the heat exchange working medium includes one or more of methane, ethane, propane, butane, isobutane, ethylene, propylene, difluoromethane, trifluoromethane, difluoroethane, trifluoroethane, tetrafluoroethane, and pentafluoroethane.

[0013] The phase change heat accumulator and the phase change cold accumulator in the energy storage structure unit both store phase change materials (PCMs), and the phase change materials include one or more of salts, waxes, and petroleum hydrocarbons.

[0014] In the present application, two phase change energy storage devices are used, one is the phase change heat accumulator between the solar heat supply unit and the organic Rankine cycle unit, the organic Rankine cycle unit utilizes low-temperature heat sources to generate electricity, and the additional electric energy can be efficiently combined with the phase change energy storage device to realize the storage and stable supply of energy. In periods of insufficient solar energy, such as at night or on cloudy days, the stored energy can effectively meet the heating demand. The phase change energy storage device can provide stable heat when needed by storing or releasing heat energy during material phase change. This combination not only improves energy utilization efficiency, but also enhances the flexibility and reliability of the system. The other is the phase change cold accumulator in the energy storage structure unit, which can be used to efficiently store and utilize the cold energy of LNG. During the cold storage process, the phase change material absorbs the cold energy of LNG and undergoes phase change, thereby storing the cold energy. When the system needs to release cold energy, the phase change material releases the previously absorbed cold energy during phase change. Through this process, the system can provide stable cold energy during periods of unstable LNG supply or high demand. This not only improves the utilization efficiency of cold energy, but also reduces the immediate load on the cold energy supply system, optimizing energy use and management. This phase change energy storage method effectively balances the fluctuations in energy supply, improving the overall reliability and energy utilization efficiency of the system.

[0015] For the LNG cold energy utilization unit, mainly by liquefied natural gas tank, liquefied natural gas pump, throttle valve and heat exchanger, expander, generator, cold storage heat exchanger is constituted, the liquefied natural gas pump is extracted from the liquefied natural gas tank and is transported to the next link to liquid LNG, improve the liquid LNG pressure, make liquid LNG in the cold energy recovery or energy conversion process can flow and handle smoothly, throttle valve controls flow by adjusting valve opening, realizes accurate pressure regulation and flow control, then enters the condenser as cold source heat exchange, the cold energy of LNG is transferred to the medium needing cooling, produces refrigeration effect, because liquefied natural gas LNG has huge cold energy potential, ORC system cannot absorb all the cold energy generated, leading to the cold energy cannot be effectively utilized, the LNG is changed into high temperature and high pressure natural gas after secondary heat exchange of heat exchanger, high temperature, high pressure working gas is driven by expander, and mechanical energy is converted into internal energy, drives generator to generate electricity, the gaseous working medium discharged into the expander becomes low-temperature working medium, and then enters the cold storage heat exchanger to exchange heat and increase temperature, and the cold energy is stored in the phase change cold storage device for user air conditioning side, and finally the gaseous natural gas discharged from the cold storage heat exchanger is adjusted in pressure, metered, and added with odor, and then enters the natural gas pipeline for user (i.e. natural gas supply equipment) to use, thus a complete LNG cold energy utilization "electricity, cold and gas three-in-one supply" system is formed.

[0016] For the organic Rankine cycle unit, main components include evaporator, generator, expander, working medium pump and condenser, when external solar energy is sufficient, the heat energy of the evaporator is mainly provided by the solar energy heating unit, when solar energy is insufficient, additional electric energy generated by the organic Rankine cycle unit can be stored in the phase change energy storage device for use in the heat exchange process. Liquid working medium is heated to a gaseous state by the evaporator, thereby providing high-temperature and high-pressure gas for the expander. The high-temperature and high-pressure working gas (working fluid) is converted into mechanical energy by the expander, and then returns to the condenser. At this time, the cold energy provided by the LNG cold energy utilization unit serves as the cold source of the condenser, cools and converts the fluid into a liquid state. Under the push of the working medium pump, the fluid returns to the evaporator from the condenser, completing a complete cycle.

[0017] The present application mainly uses phase change energy storage and LNG cold energy driving as the main body, and effectively solves the problems of small heat storage capacity, large volume, large thermal inertia and unstable output of common heating systems by optimizing the setting of the heating system and the fluid heat storage device, and greatly improves the energy utilization rate by fully utilizing the LNG cold energy source.

[0018] The present application has the following advantages:

[0019] 1、The system of the present application utilizes phase change heat storage and cold storage devices to store energy. Phase change materials can store a large amount of heat energy during the phase change process. Compared with traditional energy storage methods, it has higher energy density. Moreover, phase change energy storage is carried out at a specific temperature, which can provide stable temperature output. During periods of high demand, the stored cold or heat can be released, which helps to balance the load of the power grid and reduce the pressure of peak electricity consumption. This energy storage technology provides an efficient and reliable thermal energy management solution.

[0020] 2、The present application adopts a multi-heat source supply system, combines additional electric energy generated by the solar energy and ORC (Organic Rankine Cycle) system, and heats through the heat exchange device. This design ensures that heat energy can still be effectively utilized during peak demand periods, thereby improving the flexibility and stability of the system.

[0021] 3、The present application utilizes the low-temperature characteristics of liquefied natural gas (LNG) to achieve efficient storage and utilization of cold energy. By cooling the working medium and storing cold energy, it can be released for power generation or refrigeration during peak demand periods. Combined with the production of electricity, cooling and natural gas, it constitutes an efficient "electricity, cooling and gas tri-generation" system. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 The figure is a schematic diagram of the ORC system of the present application.

[0023] In the figure, 1 is a solar collector, 2 is a heat storage heat exchanger, 3 is a heat source pump, 4 is an evaporator, 5 is a first throttling valve, 6 is a first generator, 7 is a first expander, 8 is a working medium pump, 9 is a condenser, 10 is a phase change heat accumulator, 11 is a liquefied natural gas storage tank, 12 is a liquefied natural gas pump, 13 is a second throttling valve, 14 is a heat exchanger, 15 is a second expander, 16 is a second generator, 17 is a cold storage heat exchanger, 18 is a phase change cold accumulator, and 19 is a natural gas supply device. DETAILED DESCRIPTION

[0024] The present application will be described in detail below in conjunction with specific implementation cases. The following implementation cases will help those skilled in the art to further understand the present application, but do not limit the present application in any form.

[0025] As Figure 1As shown, the ORC system comprises a solar heat supply unit, an energy storage structure unit, an LNG cold energy utilization unit and an organic Rankine cycle unit, the LNG cold energy utilization unit is provided with a heat exchanger 14, the solar heat supply unit and the organic Rankine cycle unit are connected with the heat exchanger 14 in the LNG cold energy utilization unit, the solar heat supply unit and the organic Rankine cycle unit are connected, the solar heat supply unit, the LNG cold energy utilization unit and the organic Rankine cycle unit are connected with the energy storage structure unit, the solar heat supply unit and the LNG cold energy utilization unit provide heat source and cold source for the organic Rankine cycle unit respectively, and the working medium is stored in the organic Rankine cycle unit.

[0026] The solar heat supply unit is connected with the heat source pump 3, the heat source pump 3 drives the heat energy to exchange heat with the low-temperature fluid through the evaporator 4, and then the heat energy exchanges heat with the liquefied natural gas (LNG) through the first throttling valve 5, and the working medium flows into the solar collector 1 again after the heat exchange, thereby forming a heat supply circulation pipeline; the LNG cold energy utilization unit is connected with the phase change cold storage device 18, the generator and the natural gas production, thereby forming a complete LNG cold energy utilization "electricity, cold and gas combined supply" system.

[0027] The solar heat supply unit is composed of the solar collector 1, the heat storage heat exchanger 2 and the heat source pump 3, the solar collector 1 and the heat storage heat exchanger 2 correspond to form a solar heat collection circulation pipeline through the phase change cold storage device 10, and the high-temperature and high-pressure fluid obtaining heat from the solar collector 1 enters the evaporator 4 along the heat supply circulation pipeline under the driving of the heat source pump 3, exchanges heat with the low-temperature fluid in the organic Rankine cycle unit pipeline as a heat source, and the fluid of the solar heat supply unit still has part of heat energy after the heat exchange, needs to pass through the throttling valve 5 to control the fluid flow, exchanges heat with the LNG in the heat exchanger 14 for the second time to improve the overall efficiency of the system, and finally returns to the heat collection circulation pipeline to form a heat supply circulation.

[0028] The solar heat supply unit comprises the solar collector 1, the heat storage heat exchanger 2 and the heat source pump 3, one end of the solar collector 1 and the heat storage heat exchanger 2 is connected, the heat storage heat exchanger 2 is arranged to make the solar collector 1 and the heat storage heat exchanger 2 form a heat collection circulation pipeline, the other end of the heat storage heat exchanger 2 is connected with the phase change cold storage device 10 in the energy storage structure unit, the outlet of the heat storage heat exchanger 2 is connected with the inlet of the heat source pump 3, the outlet of the heat source pump 3 is connected with the inlet of the evaporator 4 in the organic Rankine cycle unit, and the inlet of the heat storage heat exchanger 2 is connected with the heat exchanger 14 in the LNG cold energy utilization unit.

[0029] The organic Rankine cycle unit comprises an evaporator 4, a first throttling valve 5, a first generator 6, a first expander 7, a working medium pump 8 and a condenser 9; one inlet of the evaporator 4 is connected with the outlet of the heat source pump 3 in the solar heat supply unit, another inlet of the evaporator 4 is connected with the outlet of the working medium pump 8, one outlet of the evaporator 4 is connected with the heat exchanger 14 in the LNG cold energy utilization unit through the first throttling valve 5, another outlet of the evaporator 4 is connected with the inlet of the first expander 7, the first expander 7 is connected with the first generator 6, the first generator 6 is connected with the phase change heat accumulator 10 in the energy storage structure unit, the outlet of the first expander 7 is connected with the inlet of the condenser 9, the outlet of the condenser 9 is connected with the inlet of the working medium pump 8, and the condenser 9 is also connected with the heat exchanger 14 and the second throttling valve 13 in the LNG cold energy utilization unit.

[0030] In the circulation process of the organic Rankine cycle unit, the outlet of the working medium pump 8 is sequentially connected with the evaporator 4, the first expander 7 and the inlet of the condenser 9, and the inlet of the condenser 9 is connected with the inlet of the working medium pump 8, so that the working medium pump 8 pushes the working medium from the condenser 9 back to the evaporator 4, thereby forming a complete cycle. The additional electric energy generated in the second generator 6 of the organic Rankine cycle unit is stored in the phase change heat accumulator 10, so as to meet the heat supply demand in the period of insufficient solar energy.

[0031] The outlet of the working medium pump 8 is connected with the inlet of the evaporator 4, so as to deliver the heat exchange working medium into the evaporator 4, absorb the heat energy from the solar heat supply unit, and become high-pressure and high-temperature working medium; the outlet of the evaporator 4 is connected with the inlet of the expander 7, the high-temperature and high-pressure working medium enters the expander 7 to expand and do work, thereby driving the generator 6 to generate additional electric energy; the generator 6 is connected with the phase change heat accumulator 10, the additional electric energy generated by the generator 6 is stored in the phase change heat accumulator 10, so as to be used as a heat source when the illumination is insufficient; the outlet of the expander 7 is connected with the inlet of the condenser 9, the working medium after expanding and doing work in the expander 7 enters the condenser 9 to be cooled. The cold energy in the condenser 9 comes from the low-temperature LNG in the liquefied natural gas storage tank 11; the outlet of the condenser 9 is connected with the working medium pump 8. The gaseous working medium cooled by the condenser 9 becomes liquid, and then flows into the working medium pump 8 for pressure processing, and finally is sent to the evaporator 4.

[0032] The LNG cold energy utilization unit comprises a liquefied natural gas storage tank 11, a liquefied natural gas pump 12, a second throttling valve 13, a heat exchanger 14, a second expander 15, a second generator 16, a cold storage heat exchanger 17 and a natural gas supply device 19.

[0033] The outlet of the liquefied natural gas storage tank 11 is connected with the inlet of the liquefied natural gas pump 12, the outlet of the liquefied natural gas pump 12 is connected with the inlet of the second throttling valve 13, the outlet of the second throttling valve 13 is connected with the inlet of the heat exchanger 14 through the condenser 9 in the organic Rankine cycle unit, specifically, the outlet of the second throttling valve 13 is connected with one inlet of the condenser 9, one outlet of the condenser 9 is connected with the inlet of the heat exchanger 14, the heat exchanger 14 is connected with the outlet of the evaporator 4 in the organic Rankine cycle unit through the first throttling valve 5 in the organic Rankine cycle unit, the heat exchanger 14 is connected with the inlet of the second expander 15, the heat exchanger 14 is connected with the heat storage heat exchanger 2 in the solar heat supply unit, the second expander 15 is connected with the second generator 16, the outlet of the second expander 15 is connected with the inlet of the cold storage heat exchanger 17, the outlet of the cold storage heat exchanger 17 is connected with the phase change cold storage 18 in the energy storage structure unit, the cold storage heat exchanger 17 is also connected with the natural gas supply device 19, and the natural gas supply device 19 is used for providing the liquefied natural gas for users.

[0034] The outlet of the heat storage heat exchanger 2 is connected with the inlet of the heat source pump 3, the evaporator 4, the first throttling valve 5 and the heat exchanger 14 in sequence, and the outlet of the heat exchanger 14 is connected with the inlet of the heat storage heat exchanger 2 again, so as to form a complete heat supply circulation pipeline.

[0035] The low-temperature high-pressure LNG in the liquefied natural gas storage tank 11 is discharged from the liquefied natural gas storage tank 11 by the liquefied natural gas pump 12 through pressure difference, and then the outcoming LNG is adjusted in flow by the second throttling valve 13, and then enters the condenser 9 of the organic Rankine cycle unit as a cold source to cool the circulating working medium, and the temperature of the LNG after heat exchange is slightly increased, but still contains a large amount of cold energy; the LNG from the condenser 9 enters the heat exchanger 14 to exchange heat with the heat energy from the solar heat supply unit, and the LNG after heat exchange becomes high-temperature high-pressure natural gas. The high-temperature high-pressure natural gas enters the expander 15 to do work, converts the internal energy into mechanical energy, and drives the generator 16 to generate electric energy.

[0036] The energy storage structure unit includes the phase change heat storage 10 and the phase change cold storage 18; one end of the phase change heat storage 10 is connected with the heat storage heat exchanger 2 in the solar heat supply unit, the other end of the phase change heat storage 10 is connected with the first generator 6 in the organic Rankine cycle unit, and the phase change cold storage 18 is connected with the cold storage heat exchanger 17 in the LNG cold energy utilization unit.

[0037] The solar collector 1 and the heat storage heat exchanger 2 in the solar heat supply unit are connected to form a heat collection circulation pipeline, and the heat storage heat exchanger 2 outlet, the heat source pump 3, the evaporator 4, the first throttling valve 5, the heat exchanger 14, and the heat storage heat exchanger 2 inlet are sequentially connected to form a heat supply circulation pipeline, and the heat collection circulation pipeline and the heat supply circulation pipeline both store heat exchange working medium, and the heat exchange working medium includes one or more of methane, ethane, propane, butane, isobutane, ethylene, propylene, difluoromethane, trifluoromethane, difluoroethane, trifluoroethane, tetrafluoroethane, and pentafluoroethane.

[0038] The phase change heat accumulator 10 and the phase change cold accumulator 18 in the energy storage structure unit both store phase change materials PCM, and the phase change materials include one or more of salts, waxes, and petroleum hydrocarbons.

[0039] As can be seen from the above examples, the system of the present application realizes the utilization of phase change energy storage and LNG cold energy driving, and through the setting of phase change heat storage and cold storage equipment, the heat storage and release characteristics of phase change materials are utilized to provide an efficient and reliable heat energy management solution suitable for various scenes requiring heat energy storage and regulation; by adopting a multi-heat source supply system, solar energy and ORC additional electric energy are used for heating of the heat exchange device, so that heat energy can be effectively utilized even when the light is insufficient, which is conducive to the continuous and stable operation of the system; by adopting the LNG cold energy utilization technology, LNG cold energy is used to cool the working medium, and the ultra-low temperature characteristics of the LNG cold energy are used for cold energy storage, so as to be used for power generation or refrigeration when needed, which helps to improve the energy utilization efficiency.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and are not limited thereto; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent replacement to part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A phase change energy storage and LNG cold energy driven ORC system, characterized in that: the system comprises a solar heat supply unit, an energy storage structure unit, an LNG cold energy utilization unit and an organic Rankine cycle unit, a heat exchanger (14) is arranged in the LNG cold energy utilization unit, the solar heat supply unit and the organic Rankine cycle unit are connected with the heat exchanger (14) in the LNG cold energy utilization unit, the solar heat supply unit and the organic Rankine cycle unit are connected, the solar heat supply unit, the LNG cold energy utilization unit and the organic Rankine cycle unit are connected with the energy storage structure unit, the solar heat supply unit and the LNG cold energy utilization unit provide heat source and cold source for the organic Rankine cycle unit respectively, and a working medium is stored in the organic Rankine cycle unit; the solar heat supply unit comprises a solar collector (1), a heat storage heat exchanger (2) and a heat source pump (3), one end of the solar collector (1) and the heat storage heat exchanger (2) is connected, the other end of the heat storage heat exchanger (2) is connected with a phase change heat accumulator (10) in the energy storage structure unit, the outlet of the heat storage heat exchanger (2) is connected with the inlet of the heat source pump (3), the outlet of the heat source pump (3) is connected with the organic Rankine cycle unit, and the inlet of the heat storage heat exchanger (2) is connected with the LNG cold energy utilization unit; the organic Rankine cycle unit comprises an evaporator (4), a first throttling valve (5), a first generator (6), a first expander (7), a working medium pump (8) and a condenser (9); one inlet of the evaporator (4) is connected with the heat source pump (3) in the solar heat supply unit, the other inlet of the evaporator (4) is connected with the outlet of the working medium pump (8), one outlet of the evaporator (4) is connected with the LNG cold energy utilization unit through the first throttling valve (5), the other outlet of the evaporator (4) is connected with the inlet of the first expander (7), the first expander (7) is connected with the first generator (6), the first generator (6) is connected with the phase change heat accumulator (10) in the energy storage structure unit, the outlet of the first expander (7) is connected with the inlet of the condenser (9), the outlet of the condenser (9) is connected with the inlet of the working medium pump (8), and the condenser (9) is also connected with the LNG cold energy utilization unit; the LNG cold energy utilization unit comprises a liquefied natural gas storage tank (11), a liquefied natural gas pump (12), a second throttling valve (13), a heat exchanger (14), a second expander (15), a second generator (16), a cold storage heat exchanger (17) and a natural gas supply device (19). ​ The outlet of the liquefied natural gas storage tank (11) is connected with the inlet of the liquefied natural gas pump (12), the outlet of the liquefied natural gas pump (12) is connected with the inlet of the second throttling valve (13), the outlet of the second throttling valve (13) is connected with the inlet of the heat exchanger (14) through the condenser (9) in the organic Rankine cycle unit, the heat exchanger (14) is connected with the outlet of the evaporator (4) in the organic Rankine cycle unit through the first throttling valve (5) in the organic Rankine cycle unit, the heat exchanger (14) is connected with the inlet of the second expander 15, the heat exchanger (14) is connected with the heat storage heat exchanger (2) in the solar heat supply unit, the second expander (15) is connected with the second generator (16), the outlet of the second expander (15) is connected with the inlet of the cold storage heat exchanger (17), the outlet of the cold storage heat exchanger (17) is connected with the phase change cold storage (18) in the energy storage structure unit, the cold storage heat exchanger (17) is also connected with the natural gas supply device (19), and the natural gas supply device (19) is used for providing liquefied natural gas for users.

2. The phase change thermal storage and LNG cold energy driven ORC system according to claim 1, characterized in that: The energy storage structure unit includes the phase change heat storage (10) and the phase change cold storage (18); one end of the phase change heat storage (10) is connected with the heat storage heat exchanger (2) in the solar heat supply unit, the other end of the phase change heat storage (10) is connected with the first generator (6) in the organic Rankine cycle unit, and the phase change cold storage (18) is connected with the cold storage heat exchanger (17) in the LNG cold energy utilization unit.

3. The phase change thermal storage and LNG cold energy driven ORC system according to claim 1, characterized in that: The solar heat collector (1) and the heat storage heat exchanger (2) in the solar heat supply unit are connected to form a heat collection circulation pipeline, the outlet of the heat storage heat exchanger (2), the evaporator (4), the heat exchanger (14), and the inlet of the heat storage heat exchanger (2) are sequentially connected to form a heat supply circulation pipeline, and the heat collection circulation pipeline and the heat supply circulation pipeline both store heat exchange working medium.

4. The phase change thermal storage and LNG cold energy driven ORC system according to claim 1, characterized in that: The phase change heat storage (10) and the phase change cold storage (18) in the energy storage structure unit both store phase change materials PCM, and the phase change materials include one or more of salts, waxes, and petroleum hydrocarbons.

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