Battery system and photo-thermal power station coupled power system and operation method thereof

Abstract

The invention relates to the technical field of new energy power generation and energy storage, and discloses a battery system and photo-thermal power station coupled electric power system and an operation method thereof. In the system, the battery system comprises a high-temperature heat exchanger, a motor, a compressor, an expansion machine and a condenser, the compressor, the high-temperature heat exchanger, the expansion machine and the condenser are sequentially communicated, and the condenser is communicated with the compressor; the motor is electrically connected with the compressor; the heat collection and absorption module comprises a heliostat field and a heat absorber, and the heliostat field is used for reflecting sunlight to the heat absorber; the fused salt heat storage module comprises a hot fused salt tank, a hot salt pump, a cold fused salt tank and a cold salt pump; the hot fused salt tank, the hot salt pump, the fused salt heat exchanger, the cold fused salt tank and the cold salt pump are communicated in sequence; the battery system further comprises a surplus power supply device electrically connected with the motor. The problem that in the prior art, the overall heating efficiency of fused salt is difficult to improve is solved.

Description

Technical Field

[0001] This invention relates to the field of new energy power generation and energy storage technology, specifically a power system coupled with a battery system and a solar thermal power plant, and its operation method. Background Technology

[0002] The proportion of new energy sources, represented by wind power and solar power, in the power system has increased dramatically. Large-scale new energy bases are usually located in remote areas with low local load levels and limited transmission capacity. In addition, the inherent intermittency and volatility of wind and solar power generation lead to a serious problem of "wind and solar curtailment".

[0003] Tower-type concentrated solar power (CSP) plants, as a new energy technology that simultaneously generates electricity and stores large-capacity energy (typically molten salt thermal energy), are an important solution for improving the grid's ability to absorb new energy sources. They focus solar energy through collectors to heat molten salt, and the thermal energy stored in the high-temperature molten salt can be used for continuous power generation. However, traditional CSP plants rely entirely on solar energy for energy storage; at night or on cloudy or rainy days, their molten salt thermal energy storage system cannot replenish the heat, limiting their continuous power generation capacity.

[0004] Carnot battery systems, also known as heat pump energy storage systems, are an emerging large-scale physical energy storage technology. The principle is to use electricity to drive a heat pump when there is a power surplus, converting low-grade heat energy into high-grade heat energy and storing it; when electricity is needed, the stored heat energy is used to generate electricity through a heat engine. Carnot battery systems have advantages such as large scale, long lifespan, and good environmental performance; however, they typically operate as independent units, with a single coupling method with existing renewable energy power generation facilities, leaving room for further improvement in overall system efficiency and flexibility.

[0005] Currently, there is no solution that can deeply couple the Carnot battery system with the molten salt system of a tower solar thermal power plant and flexibly switch the operating mode (series / parallel) according to the time period to maximize the absorption of wind and solar curtailment and improve the overall efficiency of the system.

[0006] The existing technology has the following shortcomings: (1) It is difficult to improve the overall heating efficiency of molten salt and reduce energy consumption by using different operating modes at different times; (2) It is difficult to overcome the limitation that the heat storage source of tower solar thermal power plants relies solely on solar energy, thus making it difficult to achieve all-weather, multi-source complementary heating of the heat storage system; (3) It is difficult to efficiently and on a large scale absorb the curtailed wind and solar power from large-scale new energy bases. Summary of the Invention

[0007] To overcome the shortcomings of existing technologies, this invention provides a power system coupled with a solar thermal power plant and its operation method, which solves the problems of difficulty in improving the overall heating efficiency of molten salt in existing technologies.

[0008] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: A power system coupled to a battery system and a solar thermal power plant includes an interconnected battery system and a solar thermal power plant, and also includes a molten salt heat exchanger, a heat exchanger inlet valve, a heat exchanger bypass valve, and a heat exchanger main valve. The solar thermal power plant includes interconnected heat collection and absorption modules and a molten salt heat storage module. in: The battery system includes a high-temperature heat exchanger, a motor, a compressor, an expander, and a condenser. The compressor, high-temperature heat exchanger, expander, and condenser are connected in sequence. The condenser is connected to the compressor, and the motor is electrically connected to the compressor. The heat collection and absorption module includes a heliostat field and a heat absorber. The heliostat field is used to reflect sunlight to the heat absorber. The molten salt thermal storage module includes a hot molten salt tank, a hot salt pump, a cold molten salt tank, and a cold salt pump, which are connected in sequence. The cold salt pump, cold salt pump outlet valve, heat absorber, and hot molten salt tank are connected in sequence. The node between the cold salt pump and the cold salt pump outlet valve, the heat exchanger inlet valve, and the high-temperature heat exchanger are connected in sequence. The high-temperature heat exchanger, the heat exchanger main valve, the node between the cold salt pump outlet valve and the heat absorber, the heat absorber, and the hot molten salt tank are connected in sequence. The high-temperature heat exchanger bypass valve, the node between the heat absorber and the hot molten salt tank, and the hot molten salt tank are connected in sequence. The battery system also includes a spare power supply unit that is electrically connected to the motor.

[0009] The beneficial effects of this invention are: Its innovative coupling method lies in the following: the high-temperature heat exchanger of the battery system is connected to the molten salt circuit of the solar thermal power plant via pipelines and valves. By switching the valves, the battery system and the collector can operate in two modes: parallel and series. In series mode, the battery system absorbs curtailed wind and solar power to preheat the molten salt, and then solar energy is used to reheat the preheated molten salt to the rated operating temperature. In parallel mode, the battery system can operate independently, absorbing curtailed wind and solar power and heating the molten salt to the rated operating temperature. This invention reduces the energy consumption of the battery system and improves system economy: In series mode, the battery system only needs to preheat the molten salt to an intermediate temperature, rather than directly heating it to the rated operating temperature. The heat pump operates in this temperature range, and its coefficient of performance (COP) is much higher than that of direct heating to the rated operating temperature, meaning that more heat energy can be stored with the same amount of electrical energy consumed, resulting in better overall system economy. This invention improves the efficiency and flexibility of solar thermal power plants: In series mode, by utilizing waste electricity to preheat molten salt, the heat load required for the absorber to heat the molten salt from ambient temperature to the target temperature is reduced, thus improving the solar energy collection efficiency and enabling the generation of more high-grade thermal energy under the same sunshine conditions. Simultaneously, the power plant's thermal storage capacity is no longer constrained by sunshine hours, significantly enhancing dispatch flexibility. This invention greatly enhances the capacity for renewable energy absorption: This invention enables the battery system to absorb not only nighttime waste electricity but also effectively utilize daytime waste electricity, achieving full-hour absorption of wind and solar waste electricity and significantly improving the overall absorption rate of large-scale renewable energy bases. This invention achieves multi-energy complementarity and system integration: This invention deeply integrates solar energy (solar thermal) and electrical energy (battery system) through a unified molten salt thermal storage system, achieving true multi-energy complementarity and system integration, improving equipment utilization and reliability.

[0010] Based on the above technical solution, the present invention can be further improved as follows.

[0011] As a preferred technical solution, the battery system is a Carnot battery system, and the surplus power supply device includes one or two of the following: a photovoltaic power generation module electrically connected to the motor, and a wind turbine generator electrically connected to the motor.

[0012] The beneficial effects of adopting the above-mentioned preferred technical solution are: The Carnot battery system has the advantages of high-efficiency energy conversion, long-term storage, and low cost. Photovoltaic power generation modules and wind turbines are commonly used solar power generation and wind power generation equipment, respectively. They have high deployment efficiency and facilitate the large-scale application of this invention.

[0013] As a preferred technical solution, the solar thermal power plant also includes a steam turbine power generation module. The steam turbine power generation module includes a high-pressure cylinder of the steam turbine, a medium and low-pressure cylinder of the steam turbine, a condenser, a condensate pump, a low-pressure heater, a deaerator, a feedwater pump, a high-pressure heater, and a molten salt heat exchanger connected in sequence. The molten salt heat exchanger is connected to the high-pressure cylinder of the steam turbine, the high-pressure cylinder of the steam turbine is connected to the high-pressure heater, the condenser is connected to the low-pressure heater, and the deaerator is connected to the high-pressure heater. It also includes a generator electrically connected to the medium and low-pressure cylinder of the steam turbine.

[0014] The beneficial effects of adopting the above-mentioned preferred technical solution are: Steam turbine generator modules facilitate the use of steam to absorb heat and generate electricity, further improving energy efficiency.

[0015] As a preferred technical solution, a solar thermal power plant is one or more of the following: tower solar thermal power plant, trough solar thermal power plant, Fresnel solar thermal power plant, and dish solar thermal power plant.

[0016] The beneficial effects of adopting the above-mentioned preferred technical solution are: Tower-type solar thermal power plants have high concentration ratios and high photothermal conversion efficiency. Their receivers have small heat dissipation areas, further optimizing the energy concentration process and offering advantages such as long-term energy storage and stable power generation. Parabolic trough-type solar thermal power plants have the advantages of flexible power generation adjustment and the ability to quickly respond to grid frequency regulation needs. Fresnel-type solar thermal power plants have the advantages of simple structure, low initial investment and operation and maintenance costs, and high land utilization. Dish-type solar thermal power plants have the advantages of high energy conversion efficiency, easy modular design, and clean and environmentally friendly operation.

[0017] Based on the above technical solutions, the present invention also provides a method for operating a power system coupled with a battery system and a solar thermal power plant.

[0018] The operation method of the power system coupled with the battery system and the solar thermal power plant includes the following steps: The molten salt in the molten salt tank is first pumped into the high-temperature heat exchanger of the Carnot battery system by a cold salt pump; The surplus power supply provides power to the motor, which drives the compressor to do work, and the compressor drives the expander to do work, preheating the molten salt in the high-temperature heat exchanger to an intermediate temperature; The preheated molten salt in the high-temperature heat exchanger enters the absorber through the main valve of the heat exchanger; The heliostat field reflects sunlight into the absorber to reheat the molten salt, bringing the temperature of the molten salt to the rated operating temperature. Molten salt that has reached its rated operating temperature is stored in a hot molten salt tank or used directly for power generation.

[0019] The beneficial effects of this invention are: This facilitates the effective utilization of surplus solar energy when it exists, significantly improving the overall absorption rate of large-scale new energy bases.

[0020] Based on the above technical solution, the present invention can be further improved as follows.

[0021] As a preferred technical solution, the intermediate temperature range is 300℃-400℃, and the rated operating temperature range is 550℃-570℃.

[0022] The beneficial effects of adopting the above-mentioned preferred technical solution are: This scope allows the present invention to cover commonly used molten salt types, making it applicable to a wide range of scenarios.

[0023] The operation method of the power system coupled with the battery system and the solar thermal power plant includes the following steps: Some or all of the molten salt in the cold molten salt tank enters the high-temperature heat exchanger sequentially through the cold salt pump and the heat exchanger inlet valve. as well as, The surplus power supply provides power to the motor, which drives the compressor to do work, and the compressor drives the expander to do work, heating the molten salt in the high-temperature heat exchanger to the rated operating temperature. Molten salt heated to the rated operating temperature enters the hot molten salt tank through the heat exchanger bypass valve; Molten salt that has reached its rated operating temperature is stored in a hot molten salt tank or used directly for power generation.

[0024] The beneficial effects of this invention are: This facilitates the effective utilization of surplus wind energy in situations where there is surplus wind energy but no surplus solar energy, significantly improving the overall absorption rate of large-scale new energy bases.

[0025] As a preferred technical solution, the operation also includes the following steps: Part or all of the molten salt in the cold molten salt tank enters the heat absorber sequentially through the cold salt pump and the cold salt pump outlet valve; The molten salt in the absorber is heated to the rated operating temperature and then enters the hot molten salt tank; Molten salt that has reached its rated operating temperature is stored in a hot molten salt tank or used directly for power generation.

[0026] The beneficial effects of adopting the above-mentioned preferred technical solution are: This facilitates the effective utilization of surplus wind energy in situations where there is excess wind energy and a small amount of solar energy that has been curtailed, significantly improving the overall absorption rate of large-scale new energy bases.

[0027] As a preferred technical solution, the rated operating temperature range is 550℃-570℃.

[0028] The beneficial effects of adopting the above-mentioned preferred technical solution are: This scope allows the present invention to cover commonly used molten salt types, making it applicable to a wide range of scenarios.

[0029] The operation method of the power system coupled with the battery system and the solar thermal power plant includes the following steps: Water is heated into steam in a molten salt heat exchanger; Steam flows sequentially through the high-pressure cylinder of the turbine, the intermediate and low-pressure cylinder of the turbine, the condenser, the condensate pump, the low-pressure heater, the deaerator, the feedwater pump, and the high-pressure heater before returning to the molten salt heat exchanger. When the steam passes through the intermediate and low-pressure cylinder of the turbine, a portion of the steam is fed into the generator to drive the generator to generate electricity.

[0030] The beneficial effects of this invention are: Steam turbine generator modules facilitate the use of steam to absorb heat and generate electricity, further improving energy efficiency.

[0031] Compared with the prior art, the present invention has the following advantages: (1) Reduce the energy consumption of the Carnot battery system and improve the system economy: In the series mode, the Carnot battery system only needs to preheat the molten salt to an intermediate temperature (such as 300-400℃) instead of directly heating it to the rated high temperature. The heat pump operates in this temperature range, and its coefficient of performance (COP) is much higher than that of the direct heating to 565℃, which means that more heat energy can be stored for the same amount of electrical energy, and the overall system economy is better.

[0032] (2) Improve the efficiency and flexibility of solar thermal power plants: In series mode, the use of surplus electricity to preheat molten salt reduces the heat load required for the absorber to heat the molten salt from ambient temperature to the target temperature, thereby improving the solar energy collection efficiency and enabling the generation of more high-grade thermal energy under the same sunshine conditions. At the same time, the thermal storage capacity of the power plant is no longer constrained by sunshine hours, and the scheduling flexibility is greatly enhanced.

[0033] (3) Greatly enhance the capacity for new energy consumption: This invention enables the Carnot battery system to not only consume abandoned electricity at night, but also to effectively utilize abandoned electricity during the day, achieving 24-hour all-time consumption of abandoned wind and solar power, and significantly improving the overall consumption rate of new energy bases.

[0034] (4) Realize multi-energy complementarity and system integration: This invention deeply integrates two energy forms, solar energy (photothermal) and electrical energy (Carnot battery system), and stores and releases them in a unified manner through a set of molten salt thermal storage system, realizing true multi-energy complementarity and system integration, and improving the utilization rate and reliability of the equipment.

[0035] (5) This invention meets the requirements of energy conservation and emission reduction, has a wide range of applications, and has good commercial prospects. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the structure of a power system coupled with a solar thermal power plant, as described in this invention.

[0037] The labels and their corresponding names in the attached diagram: 1-Absorber, 2-Hot molten salt tank, 3-Hot salt pump, 4-Molten salt heat exchanger, 5-High pressure cylinder of steam turbine, 6-Medium and low pressure cylinder of steam turbine, 7-Generator, 8-Condenser, 9-Condensate pump, 10-Low pressure heater, 11-Deaerator, 12-Feed water pump, 13-High pressure heater, 14-Cold molten salt tank, 15-Cold salt pump, 16-Cold salt pump outlet valve, 17-Heat exchanger inlet valve, 18-Heat exchanger bypass valve, 19-Heat exchanger main valve, 20-High temperature heat exchanger, 21-Motor, 22-Compressor, 23-Expander, 24-Condenser, 25-Photovoltaic power generation module, 26-Wind turbine, 27-Heliostat field, 28-Sun. Detailed Implementation

[0038] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0039] The principles and features of the present invention are described below. The embodiments given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0040] Example 1 like Figure 1 As shown, a power system coupled with a battery system and a solar thermal power plant includes an interconnected battery system and a solar thermal power plant, as well as a molten salt heat exchanger 4, a heat exchanger inlet valve 17, a heat exchanger bypass valve 18, and a heat exchanger main valve 19. The solar thermal power plant includes interconnected heat collection and absorption modules and a molten salt heat storage module. in: The battery system includes a high-temperature heat exchanger 20, a motor 21, a compressor 22, an expander 23, and a condenser 24. The compressor 22, the high-temperature heat exchanger 20, the expander 23, and the condenser 24 are connected in sequence. The condenser 24 is connected to the compressor 22, and the motor 21 is electrically connected to the compressor 22. The heat collection and absorption module includes a heliostat field 27 and a heat absorber 1. The heliostat field 27 is used to reflect sunlight to the heat absorber 1. The molten salt thermal storage module includes a hot molten salt tank 2, a hot salt pump 3, a cold molten salt tank 14, and a cold salt pump 15, which are connected in sequence. The cold salt pump 15, the cold salt pump outlet valve 16, the heat absorber 1, and the hot molten salt tank 2 are connected in sequence. The node between the cold salt pump 15 and the cold salt pump outlet valve 16, the heat exchanger inlet valve 17, and the high-temperature heat exchanger 20 are connected in sequence. The high-temperature heat exchanger 20, the heat exchanger main valve 19, the node between the cold salt pump outlet valve 16 and the heat absorber 1, the heat absorber 1, and the hot molten salt tank 2 are connected in sequence. The high-temperature heat exchanger 20, the heat exchanger bypass valve 18, the node between the heat absorber 1 and the hot molten salt tank 2, and the hot molten salt tank 2 are connected in sequence. The battery system also includes a spare power supply device that is electrically connected to the motor 21.

[0041] The beneficial effects of this invention are: Its innovative coupling method lies in the fact that the high-temperature heat exchanger of the battery system is connected to the molten salt circuit of the solar thermal power plant through pipelines and valves. By switching the valves, the battery system and the collector can operate in two modes: parallel and series. 1) Series operation mode: The battery system absorbs curtailed wind and solar power to preheat the molten salt, and then solar energy is used to reheat the preheated molten salt to the rated operating temperature. 2) Parallel operation mode: The battery system can operate independently, absorbing curtailed wind and solar power and heating the molten salt to the rated operating temperature. This invention reduces the energy consumption of the battery system and improves the system's economy: In the series mode, the battery system only needs to preheat the molten salt to an intermediate temperature, rather than directly heating it to the rated operating temperature. The heat pump operates in this temperature range, and its coefficient of performance (COP) is much higher than that of directly heating to the rated operating temperature, meaning that more heat energy can be stored with the same amount of electrical energy consumed, resulting in better overall system economy. This invention improves the efficiency and flexibility of solar thermal power plants: In series mode, by utilizing waste electricity to preheat molten salt, the heat load required for the absorber to heat the molten salt from ambient temperature to the target temperature is reduced, thus improving the solar energy collection efficiency and enabling the generation of more high-grade thermal energy under the same sunshine conditions. Simultaneously, the power plant's thermal storage capacity is no longer constrained by sunshine hours, significantly enhancing dispatch flexibility. This invention greatly enhances the absorption capacity of new energy sources: This invention enables the battery system to absorb not only nighttime waste electricity but also effectively utilize daytime waste electricity, achieving 24-hour absorption of wind and solar waste electricity and significantly improving the overall absorption rate of large-scale new energy bases. This invention achieves multi-energy complementarity and system integration: This invention deeply integrates solar energy (solar thermal) and electrical energy (battery system) through a unified molten salt thermal storage system, achieving true multi-energy complementarity and system integration, improving equipment utilization and reliability.

[0042] Based on the above technical solution, the present invention can be further improved as follows.

[0043] As a preferred technical solution, the battery system is a Carnot battery system, and the surplus power supply device includes one or two of the following: a photovoltaic power generation module 25 electrically connected to the motor 21, and a wind turbine 26 electrically connected to the motor 21.

[0044] The beneficial effects of adopting the above-mentioned preferred technical solution are: The Carnot battery system has the advantages of high-efficiency energy conversion, long-cycle storage, and low cost. The photovoltaic power generation module 25 and the wind turbine 26 are commonly used solar power generation and wind power generation equipment, respectively. They have high deployment efficiency and are convenient for large-scale application of the present invention.

[0045] As a preferred technical solution, the solar thermal power plant also includes a steam turbine power generation module. The steam turbine power generation module includes a high-pressure cylinder 5, a medium- and low-pressure cylinder 6, a condenser 8, a condensate pump 9, a low-pressure heater 10, a deaerator 11, a feedwater pump 12, a high-pressure heater 13, and a molten salt heat exchanger 4 connected in sequence. The molten salt heat exchanger 4 is connected to the high-pressure cylinder 5, the high-pressure cylinder 5 is connected to the high-pressure heater 13, the condenser 8 is connected to the low-pressure heater 10, and the deaerator 11 is connected to the high-pressure heater 13. It also includes a generator 7 that is electrically connected to the medium- and low-pressure cylinder 6 of the steam turbine.

[0046] The beneficial effects of adopting the above-mentioned preferred technical solution are: Steam turbine generator modules facilitate the use of steam to absorb heat and generate electricity, further improving energy efficiency.

[0047] As a preferred technical solution, a solar thermal power plant is one or more of the following: tower solar thermal power plant, trough solar thermal power plant, Fresnel solar thermal power plant, and dish solar thermal power plant.

[0048] The beneficial effects of adopting the above-mentioned preferred technical solution are: Tower-type solar thermal power plants have high concentration ratios and high photothermal conversion efficiency. Their receivers have small heat dissipation areas, further optimizing the energy concentration process and offering advantages such as long-term energy storage and stable power generation. Parabolic trough-type solar thermal power plants have the advantages of flexible power generation adjustment and the ability to quickly respond to grid frequency regulation needs. Fresnel-type solar thermal power plants have the advantages of simple structure, low initial investment and operation and maintenance costs, and high land utilization. Dish-type solar thermal power plants have the advantages of high energy conversion efficiency, easy modular design, and clean and environmentally friendly operation.

[0049] Based on the above technical solutions, the present invention also provides a method for operating a power system coupled with a battery system and a solar thermal power plant.

[0050] The operation method of the power system coupled with the battery system and the solar thermal power plant includes the following steps: The molten salt in the cold molten salt tank 14 is first pumped into the high-temperature heat exchanger 20 of the Carnot battery system by the cold salt pump 15; The surplus power supply device provides electrical energy to the motor 21, the motor 21 drives the compressor 22 to do work, and the compressor drives the expander 23 to do work, preheating the molten salt in the high temperature heat exchanger 20 to the intermediate temperature. The preheated molten salt in the high-temperature heat exchanger 20 enters the absorber 1 through the heat exchanger main valve 19; The heliostat field 27 reflects sunlight into the absorber 1 to reheat the molten salt, so that the temperature of the molten salt reaches the rated operating temperature. Molten salt that has reached its rated operating temperature is stored in hot molten salt tank 2 or used directly for power generation.

[0051] The beneficial effects of this invention are: This facilitates the effective utilization of surplus solar energy when it exists, significantly improving the overall absorption rate of large-scale new energy bases.

[0052] Based on the above technical solution, the present invention can be further improved as follows.

[0053] As a preferred technical solution, the intermediate temperature range is 300℃-400℃, and the rated operating temperature range is 550℃-570℃.

[0054] The beneficial effects of adopting the above-mentioned preferred technical solution are: This scope allows the present invention to cover commonly used molten salt types, making it applicable to a wide range of scenarios.

[0055] The operation method of the power system coupled with the battery system and the solar thermal power plant includes the following steps: Part or all of the molten salt in the cold molten salt tank 14 enters the high-temperature heat exchanger 20 sequentially via the cold salt pump 15 and the heat exchanger inlet valve 17. as well as, The spare power supply device provides electrical energy to the motor 21, the motor 21 drives the compressor 22 to do work, and the compressor drives the expander 23 to do work, heating the molten salt in the high temperature heat exchanger 20 to the rated operating temperature. Molten salt heated to the rated operating temperature enters the hot molten salt tank 2 through the heat exchanger bypass valve 18; Molten salt that has reached its rated operating temperature is stored in hot molten salt tank 2 or used directly for power generation.

[0056] The beneficial effects of this invention are: This facilitates the effective utilization of surplus wind energy in situations where there is surplus wind energy but no surplus solar energy, significantly improving the overall absorption rate of large-scale new energy bases.

[0057] As a preferred technical solution, the operation also includes the following steps: Part or all of the molten salt in the cold molten salt tank 14 enters the heat absorber 1 in sequence through the cold salt pump 15 and the cold salt pump outlet valve 16; The molten salt in absorber 1 is heated to the rated operating temperature and then enters the hot molten salt tank 2; Molten salt that has reached its rated operating temperature is stored in hot molten salt tank 2 or used directly for power generation.

[0058] The beneficial effects of adopting the above-mentioned preferred technical solution are: This facilitates the effective utilization of surplus wind energy in situations where there is excess wind energy and a small amount of solar energy that has been curtailed, significantly improving the overall absorption rate of large-scale new energy bases.

[0059] As a preferred technical solution, the rated operating temperature range is 550℃-570℃.

[0060] The beneficial effects of adopting the above-mentioned preferred technical solution are: This scope allows the present invention to cover commonly used molten salt types, making it applicable to a wide range of scenarios.

[0061] The operation method of the power system coupled with the battery system and the solar thermal power plant includes the following steps: Water is heated into steam in molten salt heat exchanger 4; Steam passes sequentially through the high-pressure cylinder 5 of the steam turbine, the intermediate and low-pressure cylinder 6 of the steam turbine, the condenser 8, the condensate pump 9, the low-pressure heater 10, the deaerator 11, the feedwater pump 12, and the high-pressure heater 13 before returning to the molten salt heat exchanger 4. When steam passes through the intermediate and low-pressure cylinder 6 of the steam turbine, the intermediate and low-pressure cylinder 6 inputs a portion of the steam to the generator 7 to drive the generator 7 to generate electricity.

[0062] The beneficial effects of this invention are: Steam turbine generator modules facilitate the use of steam to absorb heat and generate electricity, further improving energy efficiency.

[0063] Example 2 like Figure 1 As shown, based on Example 1, this example provides a more detailed implementation method.

[0064] This invention aims to address the shortcomings of existing technologies by providing a coupling system and method for a tower-type concentrated solar power (CSP) plant (which can also be a trough-type, Fresnel-type, or dish-type CSP plant) and a Carnot battery system (also known as a thermal battery system). The core technical problem it addresses is: 1. How to improve the overall heating efficiency of molten salt and reduce energy consumption by optimizing the system coupling method and adopting different operating modes at different times.

[0065] 2. How to overcome the limitation that tower solar thermal power plants rely solely on solar energy for heat storage and achieve all-weather, multi-source complementary heating of the heat storage system.

[0066] 3. How to more efficiently and on a larger scale absorb the curtailed wind and solar power from large-scale new energy bases.

[0067] To solve the above-mentioned technical problems, the embodiments of the present invention adopt the following technical solutions: Its innovative coupling method is as follows: the high-temperature heat exchanger of the Carnot battery system is connected to the molten salt circuit of the solar thermal power plant through pipelines and valves. By switching the valves, the Carnot battery system and the collector can form two operating modes: parallel and series.

[0068] The operating method includes: 1. Series operation mode (in cases where there is surplus solar energy that is wasted: for example, during periods of daylight): (1) The system switches to series mode. The molten salt in the cold molten salt tank 14 is first pumped into the high-temperature heat exchanger 20 of the Carnot battery system by the cold salt pump 15. At this time, the Carnot battery system operates in "charging" mode, consuming the power of the abandoned wind and solar power to drive the motor 21, which drives the compressor 22 and the expander 23 to do work, and the heat energy of the low-grade heat source is used to preheat the molten salt.

[0069] (2) The preheated molten salt then enters the tower absorber 1 through the main valve 19 of the heat exchanger, and is heated a second time by the solar energy 28 to quickly reach the rated operating temperature (e.g., 565℃).

[0070] (3) Finally, the high-temperature molten salt is stored in the hot molten salt tank 2 or used directly for power generation.

[0071] 2. Parallel operation mode (for situations where there is surplus wind energy: for example, windy periods at night when there is no sunshine or on cloudy days): A. Wind curtailment scenarios where there is surplus wind energy but no surplus solar energy: for example, applicable to windy periods at night when there is no sunshine; (1) The system switches to parallel mode. The Carnot battery system and tower receiver 1 operate independently: (2) Carnot battery system: part (or all) of the molten salt in the cold molten salt tank 14 is pumped by the cold salt pump 15 into the high temperature heat exchanger 20 through the heat exchanger inlet valve 17; at this time, the Carnot battery system is operating in the "charging" mode, consuming the curtailed wind and solar power to drive the motor 21, drive the compressor 22 and the expander 23 to do work, heat the molten salt to the rated working temperature (e.g., 565℃), and enter the hot molten salt tank 2 through the heat exchanger bypass valve 18; B. Situations where there is surplus wind energy and a small amount of solar energy available for wind curtailment: for example, windy periods on cloudy days; (3) While performing (1) and (2), due to the presence of certain light, the heat absorber can also independently heat another part of the molten salt: part (or all) of the molten salt in the cold molten salt tank 14 is heated to the rated working temperature (e.g., 565℃) by the cold salt pump 15 through the cold salt pump outlet valve 16 and then enters the hot molten salt tank 2.

[0072] The two portions of molten salt, heated to their rated temperatures by the Carnot battery system and the heat collection and absorption module respectively, are stored together in the molten salt tank 2 for subsequent continuous power generation.

[0073] Preferably, the operation of this invention not only relies on simple mode switching, but also on a multi-level, adaptive intelligent control strategy to ensure that the system always operates in the optimal state. The system's mode switching is automatically completed by the central control system, which intelligently decides and controls the opening and closing status of the valves based on parameters such as solar radiation intensity, wind and solar power curtailment signals, and grid dispatch instructions.

[0074] The present invention has the following advantages: (1) Reduce the energy consumption of the Carnot battery system and improve the system economy: In the series mode, the Carnot battery system only needs to preheat the molten salt to an intermediate temperature (such as 300-400℃) instead of directly heating it to the rated high temperature. The heat pump operates in this temperature range, and its coefficient of performance (COP) is much higher than that of the direct heating to 565℃, which means that more heat energy can be stored for the same amount of electrical energy, and the overall system economy is better.

[0075] (2) Improve the efficiency and flexibility of solar thermal power plants: In series mode, the use of surplus electricity to preheat molten salt reduces the heat load required for the absorber to heat the molten salt from ambient temperature to the target temperature, thereby improving the solar energy collection efficiency and enabling the generation of more high-grade thermal energy under the same sunshine conditions. At the same time, the thermal storage capacity of the power plant is no longer constrained by sunshine hours, and the scheduling flexibility is greatly enhanced.

[0076] (3) Greatly enhance the capacity for new energy consumption: This invention enables the Carnot battery system to not only consume abandoned electricity at night, but also to effectively utilize abandoned electricity during the day, achieving 24-hour all-time consumption of abandoned wind and solar power, and significantly improving the overall consumption rate of new energy bases.

[0077] (4) Realize multi-energy complementarity and system integration: This invention deeply integrates two energy forms, solar energy (photothermal) and electrical energy (Carnot battery system), and stores and releases them in a unified manner through a set of molten salt thermal storage system, realizing true multi-energy complementarity and system integration, and improving the utilization rate and reliability of the equipment.

[0078] (5) This invention meets the requirements of energy conservation and emission reduction, has a wide range of applications, and has good commercial prospects.

[0079] Example 3 like Figure 1 As shown, this embodiment provides a more detailed implementation method based on Embodiments 1 and 2.

[0080] This system consists of a tower-type solar thermal power plant and a Carnot battery system coupled together.

[0081] The tower-type solar thermal power plant includes a heat collection and absorption module, a molten salt thermal storage module, a steam turbine power generation module, a molten salt heat exchanger 4, a cold salt pump outlet valve 16, a heat exchanger inlet valve 17, a heat exchanger bypass valve 18, and a heat exchanger main valve 19. It uses two media (molten salt and steam). ① Molten salt heat absorption, release and storage process: Low temperature molten salt in cold molten salt tank 14 → cold salt pump 15 → cold salt pump outlet valve 16 → sunlight 28 reflected by heliostat field 27 to absorber 1 to heat molten salt → hot molten salt tank 2 → hot salt pump 3 → water is heated to high temperature and high pressure steam in molten salt heat exchanger 4 → cold molten salt tank 14; ② Steam heat absorption and power generation process: Water is heated into high-temperature and high-pressure steam in molten salt heat exchanger 4 → high-pressure cylinder 5 of steam turbine, medium and low-pressure cylinder 6 of steam turbine... high-pressure heater 13 → molten salt heat exchanger 4; high-temperature and high-pressure steam → medium and low-pressure cylinder 6 of steam turbine → generator 7.

[0082] It is worth noting that in the field of steam turbine power generation, the high pressure, medium pressure, and low pressure in this section only indicate the relative levels of internal pressure of the components. These are technical terms and do not specify a temperature range. Therefore, this section should not be interpreted as a description of "unclear pressure range".

[0083] Preferably, the high-pressure cylinder 5 of the steam turbine has a steam inlet, a steam extraction port and a steam exhaust port. The steam inlet is connected to the molten salt heat exchanger 4, the steam extraction port is connected to the high-pressure heater 13, and the steam exhaust port is connected to the steam inlet of the intermediate and low-pressure cylinder 6 of the steam turbine. The steam turbine's low-pressure cylinder 6 has a steam inlet, a steam extraction port (intermediate-pressure extraction port and low-pressure extraction port), and a steam exhaust port. The steam inlet is connected to the exhaust port of the steam turbine's high-pressure cylinder 5, the low-pressure extraction port is connected to the low-pressure heater 10, the intermediate-pressure cylinder extraction port is connected to the deaerator 11, and the exhaust port is connected to the condenser 8.

[0084] The Carnot battery system consists of a high-temperature heat exchanger 20, a motor 21, a compressor 22, an expander 23, and a condenser 24. The medium can be CO2, air, argon, etc., and the main process is as follows: The photovoltaic power generation module 25 and the wind turbine 26 drive the motor 21, which in turn drives the compressor 22 and the expander 23 to rotate and perform work. The medium is compressed to a high temperature and high pressure state by the compressor 22 → the medium enters the high temperature heat exchanger 20 to heat the molten salt → the medium enters the expander 23 to become a low temperature and low pressure state → it enters the condenser 24 to absorb heat → compressor 22.

[0085] Specific implementation methods: (1) Series mode: When the control system detects curtailed solar power, it automatically switches to series mode. The Carnot battery system is started, and the curtailed solar power (photovoltaic power generation module 25, wind turbine 26) drives the motor 21. Molten salt in the cold molten salt tank 14 is pumped into the high-temperature side heat exchanger 20 of the Carnot battery system and preheated to the intermediate temperature. Subsequently, the molten salt enters the absorber 1, is further heated by solar energy to the rated temperature, and is then stored in the hot molten salt tank 2.

[0086] (2) Parallel mode: The control system switches to parallel mode. The Carnot battery system operates independently and continuously absorbs the curtailed wind power. It directly heats the cold molten salt at 290°C to 565°C and stores it in the hot molten salt tank, so that the solar thermal power plant can continue to store the heat energy required for power generation even when there is no sunshine at night or insufficient sunshine on cloudy days, thus achieving stable power generation around the clock.

[0087] This invention may have the following characteristics: 1. The high-temperature side heat exchanger 20 is connected to the molten salt circuit of the tower solar thermal power plant through a pipeline with valves (heat exchanger inlet valve 17, heat exchanger bypass valve 18, and heat exchanger main valve 19), so that the Carnot battery system can heat the molten salt in parallel or in series with the absorber 1. 2. By controlling the opening and closing states of the valves (cold salt pump outlet valve 16, heat exchanger inlet valve 17, heat exchanger bypass valve 18, and heat exchanger main valve 19), the operating mode can be flexibly switched: when operating in series, the molten salt flows through the Carnot battery system and then through the absorber 1; when operating in parallel, the molten salt flows directly through the Carnot battery system. 3. Includes the following modes: (1) Series operation mode: the Carnot battery system is used to consume the curtailed wind and solar power to preheat the molten salt, and then the solar energy is used to reheat the preheated molten salt to the rated temperature. (2) Parallel operation mode: The Carnot battery system can work independently, absorbing the curtailed wind and solar power and heating the molten salt to the rated temperature; 4. The switching of operating modes is automatically controlled by the central control system, which receives solar irradiance, wind and solar power curtailment signals and grid dispatch instructions as input parameters; 5. In the series operation mode, the Carnot battery system preheats the molten salt to an intermediate temperature between 300°C and 400°C; 6. The Carnot battery system further includes a heat engine cycle unit for converting stored thermal energy into electrical energy output when the power grid requires it.

[0088] As described above, the present invention can be implemented well.

[0089] In the description of this invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0090] In the description of this invention, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0091] In the description of this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0092] In the description of this invention, although embodiments of the invention have been shown and described herein, it is to be understood that the above embodiments are exemplary and should not be construed as limiting the invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this invention.

[0093] In the description of this invention, all features disclosed in all embodiments of this specification, or steps in all methods or processes implied in the disclosure, may be combined and / or extended or replaced in any way, except for mutually exclusive features and / or steps.

[0094] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Based on the technical essence of the present invention, any simple modifications, equivalent substitutions, and improvements made to the above embodiments within the spirit and principles of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A power system coupled with a battery system and a solar thermal power plant, characterized in that, The battery system includes a battery system, a photo-thermal power station, a molten salt heat exchanger (4), a heat exchanger inlet valve (17), a heat exchanger bypass valve (18), a heat exchanger main valve (19), the photo-thermal power station includes a heat collecting and absorbing module, a molten salt heat storage module, and the heat collecting and absorbing module is communicated with each other; Wherein: The battery system includes a high-temperature heat exchanger (20), a motor (21), a compressor (22), an expander (23), and a condenser (24), the compressor (22), the high-temperature heat exchanger (20), the expander (23), and the condenser (24) are sequentially communicated, the condenser (24) is communicated with the compressor (22), and the motor (21) is electrically connected with the compressor (22); The heat collecting and absorbing module includes a heliostat field (27) and a heat absorber (1), and the heliostat field (27) is used for reflecting sunlight to the heat absorber (1); The molten salt heat storage module includes a hot molten salt tank (2), a hot salt pump (3), a cold molten salt tank (14), and a cold salt pump (15), and the hot molten salt tank (2), the hot salt pump (3), the molten salt heat exchanger (4), the cold molten salt tank (14), and the cold salt pump (15) are sequentially communicated; The cold salt pump (15), a cold salt pump outlet valve (16), the heat absorber (1), and the hot molten salt tank (2) are sequentially communicated, a node between the cold salt pump (15) and the cold salt pump outlet valve (16), the heat exchanger inlet valve (17), and the high-temperature heat exchanger (20) are sequentially communicated, the high-temperature heat exchanger (20), the heat exchanger main valve (19), a node between the cold salt pump outlet valve (16) and the heat absorber (1), the heat absorber (1), and the hot molten salt tank (2) are sequentially communicated, the high-temperature heat exchanger (20), the heat exchanger bypass valve (18), a node between the heat absorber (1) and the hot molten salt tank (2), and the hot molten salt tank (2) are sequentially communicated; The battery system further includes a surplus power supply device electrically connected with the motor (21).

2. The power system of claim 1, wherein, The battery system is a Carnot battery system, and the surplus power supply device includes one or both of the following: a photovoltaic power generation module (25) electrically connected with the motor (21) and a wind turbine generator (26) electrically connected with the motor (21).

3. The power system of claim 2, wherein, The photo-thermal power station further includes a steam turbine power generation module, and the steam turbine power generation module includes a steam turbine high-pressure cylinder (5), a steam turbine medium-low pressure cylinder (6), a condenser (8), a condensate pump (9), a low-pressure heater (10), a deaerator (11), a feed water pump (12), a high-pressure heater (13), and the molten salt heat exchanger (4) are sequentially communicated, the molten salt heat exchanger (4) is communicated with the steam turbine high-pressure cylinder (5), the steam turbine high-pressure cylinder (5) is communicated with the high-pressure heater (13), the condenser (8) is communicated with the low-pressure heater (10), the deaerator (11) is communicated with the high-pressure heater (13), and the steam turbine medium-low pressure cylinder (6) is electrically connected with a generator (7).

4. The power system of any one of claims 1 to 3, wherein the battery system is coupled to a solar thermal power plant. The photo-thermal power station is one or more of the following: a tower type photo-thermal power station, a trough type photo-thermal power station, a Fresnel type photo-thermal power station, and a dish type photo-thermal power station.

5. A method for operating a power system coupled with a solar thermal power plant as described in any one of claims 1 to 4, characterized in that, The operation includes the following steps: The molten salt in the cold molten salt tank (14) is first pumped into the high-temperature heat exchanger (20) of the Carnot battery system by the cold salt pump (15); The surplus power supply device provides power for the motor (21), the motor (21) drives the compressor (22) to work, and the compressor drives the expander (23) to work, preheats the molten salt in the high-temperature heat exchanger (20) to an intermediate temperature; The preheated molten salt in the high-temperature heat exchanger (20) enters the heat absorber 1 through the heat exchanger main path valve (19); The heliostat field (27) reflects sunlight into the heat absorber (1) to heat the molten salt for the second time, so that the temperature of the molten salt reaches the rated working temperature; The molten salt reaching the rated working temperature is stored in the hot molten salt tank (2) or directly used for power generation.

6. The method of claim 5, wherein the battery system is coupled to a thermal power plant. The intermediate temperature ranges from 300°C to 400°C, and the rated working temperature ranges from 550°C to 570°C.

7. A method for operating a power system coupled with a solar thermal power plant as described in any one of claims 1 to 4, characterized in that, The operation includes the following steps: Part or all of the molten salt in the cold molten salt tank (14) enters the high-temperature heat exchanger (20) in turn through the cold salt pump (15) and the heat exchanger inlet valve (17); And, The surplus power supply device provides power for the motor (21), the motor (21) drives the compressor (22) to work, and the compressor drives the expander (23) to work, preheats the molten salt in the high-temperature heat exchanger (20) to an intermediate temperature; The preheated molten salt in the high-temperature heat exchanger (20) enters the heat absorber 1 through the heat exchanger main path valve (19); The molten salt reaching the rated working temperature is stored in the hot molten salt tank (2) or directly used for power generation.

8. The method of claim 7, wherein the battery system is coupled to a thermal power plant. The operation includes the following steps: Part or all of the molten salt in the cold molten salt tank (14) enters the high-temperature heat exchanger (20) in turn through the cold salt pump (15) and the heat exchanger inlet valve (17); The molten salt in the heat absorber (1) is heated to the rated working temperature and then enters the hot molten salt tank (2); The molten salt reaching the rated working temperature is stored in the hot molten salt tank (2) or directly used for power generation.

9. The method of claim 7 or 8, wherein the battery system is coupled to a thermal power plant. The rated working temperature ranges from 550°C to 570°C.

10. The method of claim 3 or 4, wherein the battery system is coupled to a power system of a solar thermal power plant. The operation includes the following steps: Water is heated into water vapor in the molten salt heat exchanger (4); The water vapor returns to the molten salt heat exchanger (4) in turn through the high-pressure cylinder (5) of the steam turbine, the medium-low pressure cylinder (6) of the steam turbine, the condenser (8), the condensate pump (9), the low-pressure heater (10), the deaerator (11), the feed water pump (12), and the high-pressure heater (13); wherein when the water vapor passes through the medium-low pressure cylinder (6) of the steam turbine, the medium-low pressure cylinder (6) of the steam turbine inputs part of the water vapor to the generator (7) to drive the generator (7) to generate electricity.

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