ORC (organic Rankine cycle) system driven by phase change energy storage and LNG (liquefied natural gas) cold energy

Abstract

The invention discloses an ORC (organic Rankine cycle) system driven by phase change energy storage and LNG (liquefied natural gas) cold energy. A heat exchanger is arranged in the LNG cold energy utilization unit, the solar heat supply unit and the organic Rankine cycle unit are both connected with the heat exchanger in the LNG cold energy utilization unit, the solar heat supply unit is connected with the organic Rankine cycle unit, and the solar heat supply unit, the LNG cold energy utilization unit and the organic Rankine cycle unit are all connected with the energy storage structure unit. The solar heat supply unit and the LNG cold energy utilization unit respectively provide a heat source and a cold source for the organic Rankine cycle unit, a working medium is stored in the organic Rankine cycle unit, and the expansion machine, the working medium pump and the LNG cold energy utilization unit are all connected with the condenser. Phase change energy storage and LNG cold energy driving are used as main bodies, a heat supply system and fluid heat storage equipment are optimized, and full utilization of LNG cold energy is realized, so that the flexibility and stability of the system are improved, and the utilization rate of the energy is greatly improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of energy conservation of integrated energy systems, and in particular relates to an ORC system driven by phase change energy storage and LNG cold energy. Background Art

[0002] With the rapid increase in the consumption of fossil energy, energy shortage has become one of the common problems faced by mankind, so it is necessary to vigorously develop renewable energy. As an abundant renewable energy, solar energy has broad application prospects. Since solar energy can be directly developed and utilized, more and more heating systems use solar energy as a power supply energy source. However, due to the influence of changes in natural conditions such as day and night, seasons, and weather, the utilization rate of solar energy heating is not high and the system is not stable enough. Therefore, it is necessary to optimize and improve the design of solar heating systems.

[0003] With the rapid development of cold chain logistics, data centers and other industries, the demand for cold energy is also increasing. As an emerging cold source, liquefied natural gas (LNG) cold energy can meet the diverse needs of the market. During the LNG liquefaction process, the temperature of LNG is about -162°C. This low temperature characteristic allows LNG to be used in a variety of cooling and refrigeration applications when it releases cold energy. Utilizing the cold energy of LNG can effectively improve energy utilization efficiency and reduce costs. However, in conventional cold energy storage, problems such as small heat storage capacity, large exothermic temperature fluctuations, and slow reaction speed are often encountered, which leads to LNG cold energy loss and low utilization efficiency. Therefore, it is necessary to optimize and improve the thermal storage unit. Summary of the invention

[0004] In order to solve the problems existing in the background technology, the purpose of the present invention is to provide an ORC (Organic Rankine Cycle) system driven by phase change energy storage and LNG cold energy, so as to solve the characteristics of the heating system with small heat storage capacity, large volume, large thermal inertia and unstable output, and make full use of LNG cold energy to greatly improve energy utilization.

[0005] The technical solution adopted by the present invention is:

[0006] The system includes a solar heating unit, an energy storage structure unit, an LNG cold energy utilization unit and an organic Rankine cycle unit. A heat exchanger is provided in the LNG cold energy utilization unit. The solar heating unit and the organic Rankine cycle unit are both connected to the heat exchanger in the LNG cold energy utilization unit. The solar heating unit and the organic Rankine cycle unit are connected to each other. The solar heating unit, the LNG cold energy utilization unit and the organic Rankine cycle unit are all connected to 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. Working fluid is stored in the organic Rankine cycle unit.

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

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

[0009] The LNG cold energy utilization unit includes a liquefied natural gas storage tank, a liquefied natural gas pump, a second throttle 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 to the inlet of the liquefied natural gas pump, the outlet of the liquefied natural gas pump is connected to the inlet of the second throttle valve, the outlet of the second throttle valve is connected to the inlet of the heat exchanger via the condenser in the organic Rankine cycle unit, the heat exchanger is connected to the outlet of the evaporator in the organic Rankine cycle unit via the first throttle valve in the organic Rankine cycle unit, the heat exchanger is connected to the inlet of the second expander, the heat exchanger is connected to the heat storage heat exchanger in the solar heating unit, the second expander is connected to the second generator, the outlet of the second expander is connected to the inlet of the cold storage heat exchanger, the outlet of the cold storage heat exchanger is connected to the phase change cold storage in the energy storage structure unit, the cold storage heat exchanger is also connected to the natural gas supply equipment, and the natural gas supply equipment is used to provide natural gas to users.

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

[0012] The solar collector and the heat storage heat exchanger in the solar heating unit are connected to form a heat collection circulation pipeline, and the heat storage heat exchanger outlet, the evaporator, the heat exchanger, and the heat storage heat exchanger inlet are connected in sequence to form a heating circulation pipeline. The heat collection circulation pipeline and the heating circulation pipeline both store heat exchange medium, and the heat exchange 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 storage device and the phase change cold storage device in the energy storage structure unit both store phase change material PCM, and the phase change material includes one or more of salts, waxes, and petroleum hydrocarbons.

[0014] Two phase change energy storage devices are used in the present invention, one is a phase change heat storage device between the solar heating unit and the organic Rankine cycle unit. The organic Rankine cycle unit uses a low-temperature heat source to generate electricity, and its additional electric energy can be efficiently combined with the phase change energy storage device to achieve energy storage and stable supply. In periods when solar energy is insufficient, such as at night or on cloudy days, this part of the stored energy can be used to effectively meet the heating demand. The phase change energy storage device can provide stable heat when needed by storing or releasing thermal energy when the material changes phase. This combination not only improves the efficiency of energy utilization, but also enhances the flexibility and reliability of the system. The other is a phase change cold storage device present in the energy storage structure unit. The phase change cold storage device 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 this cold energy. When the system needs to release cold energy, the phase change material releases the previously absorbed cold energy during the phase change process. Through this process, the system can provide stable cold energy during unstable LNG supply or peak demand periods. This not only improves the utilization efficiency of cold energy, but also reduces the immediate load on the cold energy supply system and optimizes the use and management of energy. This phase change energy storage method effectively balances the fluctuation of energy supply and improves the overall reliability and energy utilization efficiency of the system;

[0015] The LNG cold energy utilization unit is mainly composed of a liquefied natural gas storage tank, a liquefied natural gas pump, a throttle valve and a heat exchanger, an expander, a generator, and a cold storage heat exchanger. The liquefied natural gas pump extracts LNG from the liquefied natural gas storage tank and transports the liquid LNG to the next link, while increasing the pressure of the liquid LNG so that the liquid LNG can flow and be processed smoothly during the cold energy recovery or energy conversion process. The throttle valve controls the flow rate by adjusting the valve opening to achieve precise pressure regulation and flow control. After that, it enters the condenser as a cold source for heat exchange, transferring the cold energy of LNG to the medium that needs to be cooled to produce a refrigeration effect. Since liquefied natural gas LNG has huge cold energy potential, the ORC system cannot absorb all of it. The cold energy generated by the heat exchanger results in the cold energy being unable to be effectively utilized. The excess LNG cold energy needs to be further utilized. After the LNG undergoes secondary heat exchange in the heat exchanger, it becomes high-temperature and high-pressure natural gas. The high-temperature and high-pressure working fluid gas undergoes work in the expander to convert the internal energy into mechanical energy, driving the generator to generate electricity. The gaseous working fluid discharged into the expander becomes a low-temperature working fluid after work, and then enters the cold storage heat exchanger for heat exchange and temperature rise, storing its cold energy in the phase change cold storage device for use by the user's air conditioning side. Finally, the gaseous natural gas discharged from the cold storage heat exchanger enters the natural gas pipeline for use by the user (i.e., the natural gas supply equipment) after pressure regulation, metering, and odorization. Thus, a complete "electricity cooling trigeneration" system for the utilization of LNG cold energy is formed.

[0016] For the organic Rankine cycle unit, the main components include an evaporator, a generator, an expander, a working fluid pump and a condenser. When the external solar energy is sufficient, the heat energy of the evaporator is mainly provided by the solar heating unit. When the solar energy is insufficient, the 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. The liquid working fluid is heated to a vaporized state through the evaporator, thereby providing high-temperature and high-pressure gas to the expander. The high-temperature and high-pressure working fluid gas (working fluid) converts its own internal energy into mechanical energy through the expander, and then returns to the condenser. At this time, the cold energy provided by the LNG cold energy utilization unit is used as the cold source of the condenser to cool the fluid and convert it into liquid. Driven by the working fluid pump, it returns from the condenser to the evaporator to complete a complete cycle.

[0017] The present invention is based on phase change energy storage and LNG cold energy drive. By optimizing the setting of the heating system and the fluid heat storage equipment, it effectively solves the problems of small heat storage capacity, large volume, large thermal inertia and unstable output of the common heating system. It also greatly improves the energy utilization rate by making full use of LNG cold energy.

[0018] The beneficial effects of the present invention are:

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

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

[0021] 3. The present invention utilizes the low temperature characteristics of liquefied natural gas (LNG) to achieve efficient storage and utilization of cold energy. It cools the working fluid, stores cold energy, and releases it for power generation or refrigeration during peak demand periods. It combines the production of electricity, cooling and natural gas to form an efficient "electricity, cooling and gas trigeneration" system. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Schematic diagram of the ORC system of the present invention.

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

[0024] The present invention is 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 invention, but will not limit the present invention in any form.

[0025] like Figure 1As shown, the ORC system includes a solar heating unit, an energy storage structure unit, an LNG cold energy utilization unit and an organic Rankine cycle unit. A heat exchanger 14 is provided in the LNG cold energy utilization unit. The solar heating unit and the organic Rankine cycle unit are both connected to the heat exchanger 14 in the LNG cold energy utilization unit. The solar heating unit and the organic Rankine cycle unit are connected to each other. The solar heating unit, the LNG cold energy utilization unit and the organic Rankine cycle unit are all connected to 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. Working fluid is stored in the organic Rankine cycle unit.

[0026] The solar heating unit passes through the heat source pump 3, which pushes the heat energy through the evaporator 4 to exchange heat with the low-temperature fluid, and then passes through the first throttle valve 5 for secondary heat exchange with the liquefied natural gas LNG. After the heat exchange, the working fluid flows into the solar collector 1 again to form a heating circulation pipeline; the LNG cold energy utilization unit stores cold energy through the combination of the phase change cold storage device 18, the generator generates electricity, and the production of natural gas, forming a complete "electricity cooling trigeneration" system for LNG cold energy utilization.

[0027] The solar heating unit is composed of a solar collector 1, a heat storage heat exchanger 2, and a heat source pump 3. Through the arrangement of the phase change heat accumulator 10, the solar collector 1 and the heat storage heat exchanger 2 form a solar heat collection circulation pipeline respectively. Under the promotion of the heat source pump 3, the high-temperature and high-pressure fluid that obtains heat from the solar collector 1 enters the evaporator 4 along the heating circulation pipeline, and performs a heat exchange with the low-temperature fluid in the organic Rankine cycle unit pipeline as a heat source. After the heat exchange, the fluid of the solar heating unit still has some thermal energy, and the fluid flow needs to be controlled by the throttle valve 5, and enters the heat exchanger 14 for secondary heat exchange with LNG to improve the overall efficiency of the system, and finally returns to the heat collection circulation pipeline to form a heating cycle.

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

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

[0030] During the cycle of the organic Rankine cycle unit, the outlet of the working fluid pump 8 is connected to the inlet of the condenser 9 via the evaporator 4 and the first expander 7 in sequence, and the inlet of the condenser 9 is then connected to the inlet of the working fluid pump 8, so that the working fluid pump 8 pushes the working fluid from the condenser 9 back to the evaporator 4, forming a complete cycle. The additional electric energy generated by the second generator 6 of the organic Rankine cycle unit is stored in the phase change heat storage device 10 to meet the heating demand during the period when solar energy is insufficient.

[0031] The outlet of the working fluid pump 8 is connected to the inlet of the evaporator 4, and the heat exchange working fluid is transported into the evaporator 4, where it absorbs the heat energy from the solar heating unit and becomes a high-pressure and high-temperature working fluid; the outlet of the evaporator 4 is connected to the inlet of the expander 7, and the high-temperature and high-pressure working fluid enters the expander 7 to expand and work, thereby driving the generator 6 to generate additional electric energy; the generator 6 is connected to the phase change heat accumulator 10, and the additional electric energy generated by the generator 6 is stored in the phase change heat accumulator 10 for use as a heat source when the light is insufficient; the outlet of the expander 7 is connected to the inlet of the condenser 9, and the working fluid after expansion and work in the expander 7 enters the condenser 9 for cooling. 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 to the working fluid pump 8. The gaseous working fluid cooled by the condenser 9 becomes liquid, then flows into the working fluid pump 8 for pressurization, and is finally sent to the evaporator 4.

[0032] The LNG cold energy utilization unit includes a liquefied natural gas storage tank 11, a liquefied natural gas pump 12, a second throttle 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 to the inlet of the liquefied natural gas pump 12, the outlet of the liquefied natural gas pump 12 is connected to the inlet of the second throttle valve 13, the outlet of the second throttle valve 13 is connected to the inlet of the heat exchanger 14 through the condenser 9 in the organic Rankine cycle unit, specifically, the outlet of the second throttle valve 13 is connected to an inlet of the condenser 9, one outlet of the condenser 9 is connected to the inlet of the heat exchanger 14, and the heat exchanger 14 is connected to the organic Rankine cycle unit through the first throttle valve 5 in the organic Rankine cycle unit. The outlet of the evaporator 4 is connected, the heat exchanger 14 is connected to the inlet of the second expansion machine 15, the heat exchanger 14 is connected to the heat storage heat exchanger 2 in the solar heating unit, the second expansion machine 15 is connected to the second generator 16, the outlet of the second expansion machine 15 is connected to the inlet of the cold storage heat exchanger 17, the outlet of the cold storage heat exchanger 17 is connected to the phase change cold storage 18 in the energy storage structure unit, the cold storage heat exchanger 17 is also connected to the natural gas supply equipment 19, and the natural gas supply equipment 19 is used to provide natural gas to users.

[0034] The outlet of the heat storage heat exchanger 2 is connected to the inlet of the heat exchanger 14 via the heat source pump 3, the evaporator 4, the first throttle valve 5 in sequence, and the outlet of the heat exchanger 14 is connected to the inlet of the heat storage heat exchanger 2 to form a complete heating circulation pipeline.

[0035] The low-temperature and high-pressure LNG in the liquefied natural gas storage tank 11 is discharged from the liquefied natural gas storage tank 11 by the pressure difference through the liquefied natural gas pump 12. The LNG that comes out is then regulated by the second throttle valve 13, and then enters the condenser 9 of the organic Rankine cycle unit as a cold source to cool the circulating working fluid. The temperature of the LNG after heat exchange is slightly increased, but it still contains a large amount of cold energy; the LNG that comes out of the condenser 9 enters the heat exchanger 14 to exchange heat with the heat energy from the solar heating unit, and the LNG after heat exchange becomes high-temperature and high-pressure natural gas. The high-temperature and high-pressure natural gas enters the expander 15 to do work, converting its own internal energy into mechanical energy, and at the same time drives the generator 16 to generate electrical energy.

[0036] The energy storage structure unit includes a phase change heat accumulator 10 and a phase change cold accumulator 18; one end of the phase change heat accumulator 10 is connected to the heat storage heat exchanger 2 in the solar heating unit, the other end of the phase change heat accumulator 10 is connected to the first generator 6 in the organic Rankine cycle unit, and the phase change cold accumulator 18 is connected to 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 heating unit are connected to form a heat collection circulation pipeline. The outlet of the heat storage heat exchanger 2, the heat source pump 3, the evaporator 4, the first throttle valve 5, the heat exchanger 14, and the inlet of the heat storage heat exchanger 2 are sequentially connected to form a heating circulation pipeline. The heat collection circulation pipeline and the heating circulation pipeline both store heat exchange medium, and the heat exchange 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 storage device 10 and the phase change cold storage device 18 in the energy storage structure unit both store phase change material PCM, and the phase change material includes one or more of salts, waxes, and petroleum hydrocarbons.

[0039] From the above examples, it can be seen that the system of the present invention realizes the utilization of phase change energy storage and LNG cold energy drive. By setting up phase change heat storage and cold storage equipment and utilizing the heat storage and release characteristics of phase change materials, an efficient and reliable thermal energy management solution is provided, which is suitable for various scenarios requiring thermal energy storage and regulation; by adopting a multi-heat source supply system, solar energy and ORC additional electric energy are used for heating the heat exchange device, ensuring that thermal energy can be effectively utilized even when light is insufficient, which is beneficial to the continuous and stable operation of the system; by adopting LNG cold energy utilization technology, LNG cold energy is used to cool the working fluid and the ultra-low temperature characteristics of LNG cold energy are used to store cold energy so that it can be used for power generation or refrigeration when needed, which helps to improve energy utilization efficiency.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, 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 invention.

Claims

1. An ORC system driven by phase change energy storage and LNG cold energy, characterized by: The system comprises a solar heating 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 heating unit and the organic Rankine cycle unit are both connected to the heat exchanger (14) in the LNG cold energy utilization unit. The solar heating unit and the organic Rankine cycle unit are connected to each other. The solar heating unit, the LNG cold energy utilization unit and the organic Rankine cycle unit are all connected to 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 fluid.

2. According to claim 1, an ORC system driven by phase change energy storage and LNG cold energy, characterized in that: The solar thermal unit comprises a solar thermal collector (1), a heat storage heat exchanger (2) and a heat source pump (3); the solar thermal collector (1) is connected to one end of the heat storage heat exchanger (2); the other end of the heat storage heat exchanger (2) is connected to a phase change heat storage (10) in an energy storage structure unit; the outlet of the heat storage heat exchanger (2) is connected to the inlet of the heat source pump (3); the outlet of the heat source pump (3) is connected to an organic Rankine cycle unit; and the inlet of the heat storage heat exchanger (2) is connected to an LNG cold energy utilization unit.

3. The ORC system driven by phase change energy storage and LNG cold energy according to claim 1 is characterized in that: The organic Rankine cycle unit comprises an evaporator (4), a first throttle valve (5), a first generator (6), a first expander (7), a working fluid pump (8) and a condenser (9); an inlet of the evaporator (4) is connected to a heat source pump (3) in a solar heating unit, another inlet of the evaporator (4) is connected to an outlet of the working fluid pump (8), an outlet of the evaporator (4) is connected to an LNG cold energy utilization unit through a first throttle valve (5), another outlet of the evaporator (4) is connected to an inlet of a first expander (7), the first expander (7) is connected to a first generator (6), the first generator (6) is connected to a phase change heat accumulator (10) in an energy storage structure unit, the outlet of the first expander (7) is connected to an inlet of a condenser (9), the outlet of the condenser (9) is connected to an inlet of a working fluid pump (8), and the condenser (9) is also connected to the LNG cold energy utilization unit.

4. The ORC system driven by phase change energy storage and LNG cold energy according to claim 1 is characterized in that: The LNG cold energy utilization unit comprises a liquefied natural gas storage tank (11), a liquefied natural gas pump (12), a second throttle 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 to the inlet of the liquefied natural gas pump (12), the outlet of the liquefied natural gas pump (12) is connected to the inlet of the second throttle valve (13), the outlet of the second throttle valve (13) is connected to the inlet of the heat exchanger (14) via the condenser (9) in the organic Rankine cycle unit, the heat exchanger (14) is connected to the outlet of the evaporator (4) in the organic Rankine cycle unit via the first throttle valve (5) in the organic Rankine cycle unit, the heat exchanger (14) is connected to the second expansion machine (13). The heat exchanger (14) is connected to the inlet of the cold storage heat exchanger (17), the heat exchanger (14) is connected to the heat storage heat exchanger (2) in the solar heating unit, the second expander (15) is connected to the second generator (16), the outlet of the second expander (15) is connected to the inlet of the cold storage heat exchanger (17), the outlet of the cold storage heat exchanger (17) is connected to the phase change cold storage (18) in the energy storage structure unit, and the cold storage heat exchanger (17) is also connected to the natural gas supply device (19), which is used to provide natural gas to users.

5. The ORC system driven by phase change energy storage and LNG cold energy according to claim 1 is characterized in that: The energy storage structural unit comprises a phase change heat accumulator (10) and a phase change cold accumulator (18); one end of the phase change heat accumulator (10) is connected to a heat storage heat exchanger (2) in a solar heating unit, the other end of the phase change heat accumulator (10) is connected to a first generator (6) in an organic Rankine cycle unit, and the phase change cold accumulator (18) is connected to a cold storage heat exchanger (17) in an LNG cold energy utilization unit.

6. The ORC system driven by phase change energy storage and LNG cold energy according to claim 2 is characterized by: The solar collector (1) and the heat storage heat exchanger (2) in the solar heating unit are connected to form a heat collection circulation pipeline, and 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. The heat collection circulation pipeline and the heat supply circulation pipeline both store heat exchange medium, and the heat exchange medium includes one or more of methane, ethane, propane, butane, isobutane, ethylene, propylene, difluoromethane, trifluoromethane, difluoroethane, trifluoroethane, tetrafluoroethane and pentafluoroethane.

7. The ORC system driven by phase change energy storage and LNG cold energy according to claim 2 is characterized by: The phase change heat storage device (10) and the phase change cold storage device (18) in the energy storage structure unit both store phase change material PCM, and the phase change material includes one or more of salts, waxes, and petroleum hydrocarbons.

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