Composite gradient heat pump power storage system and method based on double-bed three-bin structure

Abstract

The invention discloses a composite gradient heat pump power storage system and method based on a double-bed three-bin structure. Comprising a heat storage and heat exchange module, a cold storage and heat exchange module, an electricity storage heat pump module and a discharge heat pump module. And each of the heat storage and exchange module and the cold storage and exchange module comprises two heat exchange beds and three stockpiling bins. And the two heat exchange beds are respectively a moving bed and a fluidized bed. In the electricity storage state and the discharge state, the gas in the moving bed and the energy storage particles are subjected to countercurrent flow heat exchange through direct contact; and the gas in the fluidized bed and the energy storage particles are subjected to uniform mixing fluidization heat exchange. The heat storage temperature of the energy storage particles is increased through countercurrent flow heat exchange of the moving bed, the gas temperature after heat exchange is kept stable on the basis of the uniform heat exchange characteristic of the fluidized bed, and the heat pump module is effectively prevented from being damaged. The gas working medium is in direct contact with the energy storage particles in the bed body for heat exchange, and the problems that the energy grade is reduced due to secondary heat exchange, heat exchange pipelines are abraded by the particles, and the service life of an electricity storage system is shortened are solved.

Description

Technical Field

[0001] The present technology belongs to the field of heat pump power storage technology, and specifically relates to a composite gradient heat pump power storage system and method based on a double-bed three-compartment structure. Background Art

[0002] With the widespread adoption of renewable energy, power systems are facing intermittent and unstable power systems. To address these issues and improve power system stability and energy efficiency, energy storage technology has become a key research direction. Heat pump energy storage technology, which converts electrical energy into thermal energy for storage and then releases it as needed, offers a promising solution.

[0003] The heat pump energy storage technology based on the gas Brayton cycle is an example. The current heat and cold storage temperatures of heat pump energy storage technology are very extreme, which cannot be supported by the phase change energy storage particles currently on the market. Only sensible heat exchange energy storage technology can be used. Common sensible heat storage technologies include fixed bed, moving bed, fluidized bed and guide trough heat exchange energy storage technology with a similar principle to the moving bed.

[0004] Currently, heat pump energy storage systems commonly use fixed-bed technology, where gas passes through a bed of fixed solid energy storage particles to transfer heat. However, this technology offers the lowest energy storage density and heat transfer efficiency among all technologies, and its heat transfer controllability is also the worst, limiting its commercial adoption.

[0005] Although the moving bed technology has slightly improved the heat transfer efficiency, the heat transfer controllability is still poor, so it is rarely used in heat pump power storage systems; the guide channel heat transfer energy storage technology with a similar principle (liquid is discharged from one channel and flows into another empty channel after heat exchange) has improved the controllability of heat transfer, but this improvement requires the addition of a gas-liquid heat exchanger, which results in heat transfer losses. On the other hand, the high-temperature molten salt material that matches it is not mature and is highly corrosive to metals. The system economy and safety are poor, and there is still a gap from practical application.

[0006] Among the above technologies, fluidized bed technology is mature and has the highest heat transfer efficiency and the best heat transfer control capability due to its strong mixing effect between the gas and solid phases. However, precisely because the heat transfer of the fluidized bed is too strong, the outlet temperatures of the gas and solid phases are very close, making it difficult to achieve countercurrent heat transfer. The gas and solid phase temperatures tend to be consistent, which means that if a higher heat storage temperature is required, the gas outlet temperature after heat exchange will also be higher, and the energy utilization rate in the gas is very low. A large number of fluidized beds need to be connected in series to achieve the countercurrent heat transfer that can be achieved by a single fixed bed or moving bed. Therefore, fluidized bed technology has not been applied in heat pump power storage systems.

[0007] From the perspective of the entire system, ensuring the stability of the compressor and expander inlet gas parameters is an important condition for the stable operation of the entire system. However, the currently commonly used fixed bed technology and the slightly evolved fluidized bed technology require changing the outlet gas volume to control the heat exchange process, which is not conducive to the efficiency of the expander and compressor. The heat exchange process equilibrium time is relatively long, and the outlet gas temperature is also unstable. Summary of the Invention

[0008] The present invention aims to provide a composite gradient heat pump energy storage system based on a dual-bed, three-compartment structure. Taking the heat storage process as an example, this novel "dual-bed, three-compartment" system utilizes a moving bed to maintain a high solid-phase heat storage temperature at the outlet (or, in other words, countercurrent flow creates a wide temperature difference between the solid and gas phase outlets, allowing for sufficient heat absorption), while a fluidized bed ensures stable gas phase parameters at the outlet. This overcomes significant drawbacks of energy storage technology in heat pump energy storage systems. On the one hand, the moving bed achieves countercurrent heat exchange, widening the temperature difference between the solid and gas phase outlets, ensuring both a high heat storage temperature and full utilization of the heat in the gas. On the other hand, the gas parameters at the moving bed outlet are unstable, so a fluidized bed is added in series after it. This fully utilizes the enhanced heat exchange, continuous operation, and strong controllability of fluidized bed technology, improving the system's heat exchange efficiency, energy storage density, and control accuracy, ensuring stable parameters of the heat pump energy storage system and maintaining high storage and discharge efficiency.

[0009] In its first aspect, the present invention provides a composite gradient heat pump power storage system and method based on a dual-bed, three-bin structure. The system comprises a heat storage and heat exchange module, a cold storage and heat exchange module, an electric storage heat pump module, and a discharge heat pump module. Both the heat storage and cold storage heat exchange modules comprise two heat exchange beds and three stacking bins. The two heat exchange beds are a moving bed and a fluidized bed, respectively. The three stacking bins are a first stacking bin, a second stacking bin, and a third stacking bin.

[0010] In the heat storage and heat exchange module, the temperature gradient of the energy storage particles stored in the first, second, and third silos increases. In the cold storage and heat exchange module, the temperature gradient of the energy storage particles stored in the first, second, and third silos decreases.

[0011] In both the storage and discharge states, the energy storage particles maintain a conveying direction, flowing from the fluidized bed, through the second silo, and toward the moving bed. The gas maintains a flow direction from the fluidized bed toward the moving bed. In the moving bed, the gas and energy storage particles undergo direct countercurrent heat exchange. The gas flow rate in the fluidized bed is controlled to fluidize the energy storage particles, allowing for uniform mixing and fluidized heat exchange. This maintains a stable output airflow temperature from the fluidized bed, improving system stability and preventing damage to the storage and discharge heat pump modules due to input gas temperature fluctuations.

[0012] In the energy storage state, the energy storage particles in the third silo are transported to the fluidized bed; the energy storage particles output from the moving bed are transported to the first silo. The third silo, fluidized bed, second silo, moving bed, and first silo in the heat storage and cold storage modules are sequentially connected, forming a material storage path for transporting the energy storage particles. The gas and solid phases in the heat storage and cold storage modules directly contact and exchange heat within the bed, storing heat or cold. Specifically, the heat storage module stores heat, while the cold storage module stores cold. The moving bed uses countercurrent heat exchange to achieve an ideal, high-quality temperature for the energy storage particles, significantly reducing the gas outlet temperature (to fully absorb heat or cold). The gas flow rate in the fluidized bed exceeds the critical fluidization velocity, allowing for uniform mixing of the gas and energy storage particles through fluidized heat exchange. This fluidized heat exchange is sufficient and quickly reaches equilibrium, improving the efficiency of heat exchange during the energy storage process. The temperature of the fluidized bed's output airflow is also kept stable, enhancing system stability and preventing damage to the energy storage heat pump module.

[0013] During the discharge state, the energy storage particles in the first silo are transported to the fluidized bed; the energy storage particles output by the moving bed are transported to the third silo. The first silo, fluidized bed, second silo, moving bed, and third silo in the heat storage and cold storage modules are sequentially connected, forming a material energy release path for transporting the energy storage particles. The gas and solid phases in the heat storage and cold storage modules come into direct contact within the bed, releasing heat or cold from the energy storage particles. Specifically, the heat storage module releases heat, while the cold storage module releases cold. Countercurrent heat exchange in the moving bed significantly increases the gas outlet temperature and significantly reduces the solid outlet temperature (sufficient heat or cold release). The gas flow rate in the fluidized bed exceeds the critical fluidization velocity, allowing for uniform mixing of the gas and energy storage particles through fluidized heat exchange.

[0014] In an ideal Carnot cycle, a high-temperature reservoir and a low-temperature reservoir are required, and the temperature difference between the two drives the cycle. The greater the temperature difference between the two, the closer the power storage process is to a 100% efficient Carnot cycle. Therefore, the higher the system's heat storage temperature and the lower the cold storage temperature, the higher the efficiency of the power storage system. The present invention distinguishes between a moving bed and a fluidized bed based on the direct contact heat exchange of a highly efficient fluidized bed. The gas velocity in the moving bed is controlled below the critical fluidization velocity, and countercurrent heat exchange is performed, which increases the temperature difference between heat storage and cold storage, thereby improving the power storage efficiency. At the same time, the gas velocity in the fluidized bed is controlled above the critical fluidization velocity. While fully exchanging heat, the airflow output temperature of the heat storage heat exchange module and the cold storage heat exchange module is also controlled within the ideal range, preventing the compressor and expander from operating in an inefficient range or even being damaged due to frequently fluctuating gas parameters.

[0015] Preferably, the energy storage heat pump module includes an energy storage compressor, an energy storage expander, and an electric motor. The discharge heat pump module includes a discharge compressor, a discharge expander, and a generator. The rotating shafts of the energy storage compressor and the energy storage expander are coaxially fixed and connected to the output shaft of the electric motor. The rotating shafts of the discharge compressor and the discharge expander are coaxially fixed and connected to the input shaft of the generator.

[0016] Preferably, the gas outlet of the fluidized bed is connected to a dust collector.

[0017] Preferably, in the electricity storage state, the output port of the electricity storage compressor, the moving bed and fluidized bed in the heat storage and heat exchange module, the electricity storage expander, the moving bed and fluidized bed in the cold storage and heat exchange module, and the input port of the electricity storage compressor are connected in sequence to form an electricity storage gas circulation loop.

[0018] In the discharge state, the output port of the discharge compressor, the moving bed in the heat storage and heat exchange module, the fluidized bed, the discharge expander, the moving bed in the cold storage and heat exchange module, the fluidized bed, and the input port of the discharge compressor are connected in sequence to form a discharge gas circulation loop.

[0019] Preferably, a switching control module is further included, which includes a plurality of three-way valves; the flow path of the gas is controlled to switch between the power storage gas circulation loop and the power storage gas circulation loop by controlling the conduction paths of the three-way valves.

[0020] Preferably, the gas outlet and particle feed port of the moving bed are both arranged at the top; the gas input port and particle discharge port of the moving bed are both arranged at the bottom.

[0021] Preferably, the gas outlet and particle feed port of the fluidized bed are both located at the top; the gas input and particle discharge port of the fluidized bed are both located at the bottom. A porous solid particle distributor is provided at the top of the fluidized bed's inner cavity; the solid particle distributor is connected to the particle feed port of the fluidized bed. A porous gas distributor is provided at the bottom of the fluidized bed's inner cavity; the gas distributor is connected to the gas outlet.

[0022] Preferably, the gas inlet of the fluidized bed is provided with a fan, which can supplement the gas flow during the system startup phase or when the gas volume is insufficient, and help to quickly establish a balance.

[0023] Preferably, the composite gradient heat pump power storage system also includes a power storage regenerative device, wherein the power storage regenerative device is provided with a first heat exchange channel and a second heat exchange channel for mutually exchanging heat. The first heat exchange channel is connected in series to the input pipe of the power storage expander; the second heat exchange channel is connected in series to the input pipe of the power storage compressor. During the power storage process, the gas before entering the power storage expander and the gas before entering the power storage compressor exchange heat in countercurrent, fully utilizing waste heat and cold to preheat the compressor inlet gas and precool the expander inlet gas, thereby improving the system's power storage efficiency.

[0024] Preferably, a multi-stage spoiler is provided inside the moving bed, on which a wave-shaped spoiler is provided to enhance gas-solid heat exchange in the bed.

[0025] Preferably, one or more gas dryers are connected to the gas pipelines connecting the heat storage and heat exchange module, the cold storage and heat exchange module, the electric storage heat pump module and the discharge heat pump module to prevent water freezing and damaging the energy storage particles during the low-temperature process.

[0026] Preferably, a stirrer is provided in the second silo; the stirrer is used to evenly mix the energy storage particles in the second silo with the original energy storage particles in the second silo, so that during the discharge process, the energy storage particles with relatively high / low temperature at the fluidized bed outlet are evenly mixed with the original particles, thereby improving the energy storage quality.

[0027] In a second aspect, the present invention provides a composite gradient heat pump power storage method based on a dual-bed, three-compartment structure, which uses the aforementioned composite gradient heat pump power storage system. The method is as follows: During the electricity storage process, the switching control module controls the conduction of the electricity storage gas circulation loop. The gas is compressed and heated in the electricity storage compressor, and the gas flows along the electricity storage gas circulation loop; the heat storage heat exchange module and the cold storage heat exchange module both transport energy storage particles along the third pile silo, fluidized bed, second pile silo, moving bed, and first pile silo. In the moving bed, the gas and energy storage particles exchange heat in a countercurrent manner; in the fluidized bed, the gas and energy storage particles exchange heat in a fluidized state, so that the gas is output at a stable temperature. After heat exchange, the energy storage particles in the fluidized bed are stored in the second pile silo; after heat exchange, the energy storage particles in the moving bed are stored in the first pile silo, and the electrical energy is stored in the form of heat and cold.

[0028] During the discharge process, the switching control module controls the conduction of the discharge gas circulation loop. The gas flows along the discharge gas circulation loop; the heat storage and heat exchange modules and the cold storage and heat exchange modules transport energy storage particles along the first pile silo, fluidized bed, second pile silo, moving bed, and third pile silo. In the moving bed, the gas and energy storage particles exchange heat in a countercurrent manner; in the fluidized bed, the gas and energy storage particles fluidize and exchange heat, so that the gas is output at a stable temperature. After heat exchange, the energy storage particles in the fluidized bed are stored in the second pile silo; after heat exchange, the energy storage particles in the moving bed are stored in the third pile silo; the gas with a higher temperature after heat exchange drives the electric storage expander to work on the electric motor and output electrical energy.

[0029] The present invention has the following beneficial effects.

[0030] The present invention provides a heat storage / cold exchange module with a dual-bed, three-compartment structure. During the energy storage process, the solid discharge temperature of the moving bed is controlled to the target heat storage / cold temperature T1 (e.g., 500°C / -100°C). Countercurrent heat exchange in the moving bed widens the temperature difference between the solid phase outlet and the gas phase outlet, ensuring sufficient absorption of heat / cold from the gas and storage at higher / lower temperatures. However, the gas outlet temperature of the moving bed is difficult to precisely control. Therefore, a fluidized bed is connected in series with the module to control its exhaust temperature to the target temperature T2 (e.g., 100°C / 10°C). The fluidized bed exhibits intense heat exchange and a short equilibrium time. Simply controlling the feed and discharge rates effectively maintains stable gas temperatures at the energy storage expander and compressor inlets, improving system stability and ensuring efficiency. During the discharge process, the moving bed in this dual-bed, three-compartment structure acts as a countercurrent heat storage bed, achieving a higher heat storage temperature and lower gas outlet temperature through countercurrent heat exchange. The fluidized bed, acting as a gas phase parameter control bed, precisely controls the outlet gas temperature, ensuring system stability.

[0031] The present invention utilizes the two beds to play a complementary role in the energy storage and discharge processes, giving full play to the advantages of the fluidized bed's efficient heat exchange and easy process control, thereby achieving stable outlet gas temperature. As a result, there is no need to control the outlet gas temperature by adjusting the air volume during the cold and heat storage processes, thereby maintaining the gas flow rate within the optimal range for achieving particle fluidization, thus avoiding unnecessary efficiency losses while maintaining efficient heat exchange.

[0032] The dual-bed, three-bin heat storage / cold exchange module of this invention features three storage bins with temperature gradients. While providing efficient heat exchange, the unidirectional flow and temporary storage of energy storage particles maintains the particle temperature within both beds within a stable range, enabling precise control of the module's outlet temperature. Furthermore, the cascade heat exchange design significantly improves energy efficiency and avoids waste heat and cold losses during operation of the heat pump power storage system.

[0033] The present invention uses gaseous working fluid to directly contact and exchange heat with the energy storage particles in the bed, stores the absorbed heat / cold in the energy storage particles in the form of sensible heat, and directly moves it out of the bed into the stockpile bin; there is no need to arrange secondary heat exchange pipes in the bed for indirect heat exchange, thus avoiding the problems of energy grade reduction caused by secondary heat exchange, particle wear of heat exchange pipes, and shortened life of the power storage system.

[0034] The present invention utilizes the advantage of the fluidized bed that can continuously load and unload, designs a continuous feeding and unloading circulation system, realizes the continuous feeding and unloading control through a rotary valve, and transports materials through an insulated conveyor belt. It can continuously transfer the energy storage particles carrying heat / cold to the corresponding stacking bin. The energy storage particles in the stacking bin are compactly stacked, which greatly improves the energy storage density compared to the fixed bed technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 Schematic diagram of the flow of gas and energy storage particles during the electricity storage process of the present invention.

[0036] Figure 2 Schematic diagram of the flow of gas and energy storage particles during the discharge process of the present invention.

[0037] Figure 3 It is a structural schematic diagram of the moving bed in the present invention.

[0038] Figure 4 Schematic diagram of the structure of the fluidized bed in the present invention.

[0039] Figure 5 It is a structural schematic diagram of the material storage bin in the present invention.

[0040] Figure 1: 1. heat storage heat exchange module; 1-1. first heat storage pile silo; 1-2. heat storage moving bed; 1-3. second heat storage pile silo; 1-4. heat storage fluidized bed; 1-5. third heat storage pile silo; 2. cold storage heat exchange module; 2-1. first cold storage pile silo; 2-2. cold storage moving bed; 2-3. second cold storage pile silo; 2-4. cold storage fluidized bed; 2-5. third cold storage pile silo; 3. electric storage heat pump module; 3-1. electric storage compressor; 3-2. electric storage expander; 3-3. electric motor; 4. discharge heat exchange module Pump module; 4-1, discharge compressor; 4-2, discharge expander; 4-3, generator; 5, first dust collector; 6, second dust collector; 7, energy storage and heat recovery device; 8, agitator; 9, first three-way valve; 10, second three-way valve; 11, third three-way valve; 12, fourth three-way valve; A1, moving bed gas inlet; A2, moving bed gas outlet; B1, moving bed feed inlet; B2, moving bed energy storage outlet; B3, discharge outlet; C1, fluidized bed gas inlet; C2, fluidized bed gas outlet. D1, fluidized bed outlet; D2, fluidized bed energy storage feed inlet; E1, silo inlet; E2, silo outlet. DETAILED DESCRIPTION

[0041] The present invention will be further described below with reference to the accompanying drawings.

[0042] like Figure 1 and Figure 2 As shown, a composite gradient heat pump power storage system based on a dual-bed, three-compartment structure includes a heat storage and heat exchange module 1, a cold storage and heat exchange module 2, an electric storage heat pump module 3, a discharge heat pump module 4, a dust removal module, and a switching control module. The electric storage heat pump module 3 includes an electric storage compressor 3-1, an electric storage expander 3-2, and an electric motor 3-3. The rotating shafts of the electric storage compressor 3-1 and the electric storage expander 3-2 are coaxially fixed and connected to the output shaft of the electric motor 3-3. The discharge heat pump module 4 includes a discharge compressor 4-1, a discharge expander 4-2, and a generator 4-3. The rotating shafts of the discharge compressor 4-1 and the discharge expander 4-2 are coaxially fixed and connected to the input shaft of the generator 4-3.

[0043] like Figure 3 and Figure 4 As shown, the heat storage and heat exchange module 1 and the cold storage and heat exchange module 2 have the same structure, each comprising three stacking silos and two heat exchange beds; the two heat exchange beds are a moving bed and a fluidized bed, respectively. The moving bed has two gas interfaces and three particle interfaces. The two gas interfaces are the moving bed gas inlet A1 and the moving bed gas outlet A2. The three particle interfaces include the moving bed feed inlet B1, the moving bed electricity storage outlet B2, and the moving bed discharge outlet B3. The moving bed gas inlet A1, the moving bed electricity storage outlet B2, and the moving bed discharge outlet B3 are located at the bottom of the moving bed; the moving bed gas outlet A2 and the moving bed feed inlet B1 are both located at the top of the moving bed. The fluidized bed has two gas interfaces and three particle interfaces. The two gas interfaces are the fluidized bed gas inlet C1 and the fluidized bed gas outlet C2. The three particle interfaces include the fluidized bed outlet D1, the fluidized bed electricity storage feed inlet D2, and the fluidized bed discharge feed inlet D3. The fluidized bed gas inlet C1 and fluidized bed outlet D1 are both arranged at the bottom of the fluidized bed, and the fluidized bed gas outlet C2, fluidized bed electricity storage feed port D2, and fluidized bed discharge feed port D3 are all arranged at the top of the fluidized bed.

[0044] In some embodiments, a porous solid particle distributor is provided at the top of the fluidized bed's inner cavity; the solid particle distributor is connected to the fluidized bed's electricity storage inlet D2 and the fluidized bed's discharge inlet D3. Preferably, a porous gas distributor is provided at the bottom of the fluidized bed's inner cavity; the gas distributor is connected to the fluidized bed's gas inlet C1. The solid particle distributor and the liquid distributor are used to optimize the flow and contact between the gas and solid phases, enhancing heat exchange.

[0045] Both moving beds and fluidized beds exchange heat through direct contact between energy storage particles and gaseous media; the difference is that the energy storage particles in the fluidized bed are fluidized under the airflow, and the energy storage particles and gaseous media are evenly mixed for heat exchange; while the energy storage particles in the moving bed exchange heat with the gaseous medium in countercurrent flow.

[0046] During operation, the gas flow rates in the moving bed and fluidized bed are different. When designing the bed structure of the moving bed and fluidized bed, the gas flow rate is controlled by controlling the furnace size according to the designed compressor flow rate. For the moving bed, it is necessary to ensure that the gas input flow rate is lower than the critical fluidization velocity of the energy storage particles. v 0; In this embodiment, the gas input flow rate in the moving bed is preferably 0.3 v 0. For fluidized beds, the gas input velocity must be higher than the critical fluidization velocity, so that the particles in the bed are in a fluidized state (specifically, the particles are constantly floating and rolling in the flowing air flow), which enhances heat exchange. The flow rate is generally designed to be 1.2 v 0~1.5 v 0 (preferably 1.2 v 0).

[0047] Therefore, the moving bed is designed to have a larger cross-sectional area and a larger bed diameter, while the fluidized bed is designed to have a smaller cross-sectional area and a smaller bed diameter. The bed height requires further confirmation through numerical simulation; in this example, the height-to-diameter ratio of the fluidized bed is set to (1-3):1, while the height-to-diameter ratio of the moving bed is set to (5-10):1, resulting in a larger moving bed overall.

[0048] like Figure 5 As shown, the three stacking silos are the first, second, and third stacking silos, and each of the three stacking silos is provided with a silo input port E1 and a silo output port E2. The silo input port E1 is located at the top of the silo, and the silo output port E2 is located at the bottom of the silo.

[0049] During the storage and discharge process, the energy storage particles in the moving bed undergo countercurrent heat exchange with the gas. Due to the characteristics of countercurrent heat exchange, the temperature of the particles output by the moving bed can be higher than the gas temperature, allowing the moving bed to complete the main heat exchange process with a large temperature difference. However, the gas output temperature of the moving bed is difficult to accurately control. The temperature difference between the gas input temperature and the energy storage input temperature in the fluidized bed is small, so the heat exchange capacity is small. However, the energy storage particles entering the fluidized state are evenly mixed with the gas, and sufficient heat exchange occurs, making the gas output temperature of the fluidized bed very close to the gas input temperature, thereby controlling the gas output temperature of the fluidized bed within a stable range, avoiding damage to the compressor and expander due to excessive changes in the speed and amplitude of the gas temperature input.

[0050] Due to the difference in the flow direction of the energy storage particles during storage and discharge, the temperature input into the second pile silo is different during storage and discharge; therefore, a stirrer 8 is provided in the second pile silo to quickly and evenly mix the energy storage particles of different temperatures in the second pile silo, so that the temperature of the energy storage particles at different positions in the second pile silo is uniform.

[0051] The silo output port E2 of the third silo, the fluidized bed discharge feed port D3 and fluidized bed discharge port D1 of the fluidized bed, the silo input port E1 and silo output port E2 of the second silo, the moving bed feed port B1 and moving bed storage discharge port B2 of the moving bed, and the silo input port E1 of the first silo are connected in sequence to form a material energy storage path (see Figure 1 ).

[0052] The silo output port E2 of the first silo, the fluidized bed energy storage feed port D2 and the fluidized bed discharge port D1 of the fluidized bed, the silo input port E1 and the silo output port E2 of the second silo, the moving bed feed port B1 and the moving bed discharge discharge port B3 of the moving bed are connected in sequence to form a material energy release path (see Figure 2 ).

[0053] In the heat storage and heat exchange module 1, the moving bed and the fluidized bed are respectively recorded as the heat storage moving bed 1-2 and the heat storage fluidized bed 1-4; the first stacking silo, the second stacking silo, and the third stacking silo are respectively recorded as the first heat storage stacking silo 1-1, the second heat storage stacking silo 1-3, and the third heat storage stacking silo 1-5.

[0054] During the electricity storage process, the energy storage particles flow in the order of the third heat storage pile silo 1-5, the heat storage fluidized bed 1-4, the second heat storage pile silo 1-3, the heat storage moving bed 1-2, and the first heat storage pile silo 1-1, and the temperature of the energy storage particles increases gradually; the high-temperature gas passes through the heat storage fluidized bed 1-4 and the heat storage moving bed 1-2 in turn, storing heat in the energy storage particles.

[0055] As an example of optional temperature settings, during the energy storage process, the energy storage particle input temperature of the thermal storage moving beds 1-2 is 200°C, the energy storage particle output temperature is 500°C, the gas input temperature is 520°C, and the gas output temperature is 320°C. For the thermal storage fluidized beds 1-4, the energy storage particle input temperature is 100°C, the energy storage particle output temperature is 200°C, the gas input temperature is 320°C, and the gas output temperature is 210°C. The gas input temperature on the high-temperature side of the thermal storage regeneration unit (the heat exchange channel connected to thermal storage heat exchange module 1) is 210°C, and the high-temperature gas output temperature is 10°C. The gas input temperature on the low-temperature side of the thermal storage regeneration unit (the heat exchange channel connected to cold storage heat exchange module 2) is -5°C, and the high-temperature gas output temperature is 195°C.

[0056] During the discharge process, the energy storage particles flow in the order of the first heat storage pile silo 1-1, the heat storage fluidized bed 1-4, the second heat storage pile silo 1-3, the heat storage moving bed 1-2, and the second heat storage pile silo 1-3, and the temperature of the energy storage particles decreases gradually; the low-temperature gas absorbs heat and increases in temperature by passing through the heat storage fluidized bed 1-4 and the heat storage moving bed 1-2 in turn; As an example of optional temperature settings, the energy storage particle input temperature of the thermal storage moving bed 1-2 during the power storage process is between 200°C and 410°C, the energy storage particle output temperature is 100°C, the gas input temperature is 90°C, and the gas output temperature is 190-400°C; the energy storage particle input temperature of the thermal storage fluidized bed 1-4 is 500°C, the energy storage particle output temperature is 495°C, the gas input temperature is 190-400°C, and the gas output temperature is 490°C. In the cold storage heat exchange module 2, the moving bed and the fluidized bed are respectively recorded as the cold storage moving bed 2-2 and the cold storage fluidized bed 2-4; the first stack silo, the second stack silo, and the third stack silo are respectively recorded as the first cold storage stack silo 2-1, the second cold storage stack silo 2-3, and the third cold storage stack silo 2-5; During the electricity storage process, the energy storage particles flow in the order of the third cold storage pile silo 2-5, the cold storage fluidized bed 2-4, the second cold storage pile silo 2-3, the cold storage moving bed 2-2, and the first cold storage pile silo 2-1, and the temperature of the energy storage particles decreases gradually; the low-temperature gas passes through the cold storage fluidized bed 2-4 and the cold storage moving bed 2-2 in turn, storing the cold energy in the energy storage particles.

[0057] As an example of an optional temperature setting, the energy storage particle input temperature of the cold storage moving bed 2-2 during the power storage process is 0°C, the energy storage particle output temperature is -100°C, the gas input temperature is -120°C, and the gas output temperature is -50°C; the energy storage particle input temperature of the cold storage fluidized bed 2-4 is 30°C, the energy storage particle output temperature is 0°C, the gas input temperature is -50°C, and the gas output temperature is -5°C.

[0058] During the discharge process, the energy storage particles flow in the order of the first cold storage pile silo 2-1, the cold storage fluidized bed 2-4, the second cold storage pile silo 2-3, the cold storage moving bed 2-2, and the second cold storage pile silo 2-3, and the temperature of the energy storage particles increases gradually; the gas absorbs cold energy and cools down by passing through the cold storage fluidized bed 2-4 and the cold storage moving bed 2-2 in turn.

[0059] As an example of an optional temperature setting, the energy storage particle input temperature of the cold storage moving bed 2-2 during the power storage process is between -40°C and 0°C, the energy storage particle output temperature is 30°C, the gas input temperature is 180°C, and the gas output temperature is -30~10°C; the energy storage particle input temperature of the cold storage fluidized bed 2-4 is -100°C, the energy storage particle output temperature is -95°C, the gas input temperature is -30~10°C, and the gas output temperature is -90°C.

[0060] During the storage and discharge process, the main heat exchange process is carried out in the moving bed with countercurrent heat exchange; the output gas temperature of the moving bed is unstable; while the fluidized bed stabilizes the output gas near the target value through efficient fluidization heat exchange.

[0061] The switching control module includes a first three-way valve 9, a second three-way valve 10, a third three-way valve 11, and a fourth three-way valve 12. The three flow ports of the first three-way valve 9 are respectively connected to the output port of the electric storage compressor 3-1, the moving bed gas input port A1 of the heat storage moving bed 1-2, and the output port of the discharge compressor 4-1. The three flow ports of the second three-way valve 10 are respectively connected to the input port of the discharge expander 4-2, the fluidized bed gas output port C2 of the heat storage fluidized bed 1-4, and the input port of the electric storage expander 3-2. The three flow ports of the third three-way valve 11 are respectively connected to the output port of the electric storage expander 3-2, the moving bed gas input port A1 of the cold storage moving bed 2-2, and the output port of the discharge expander 4-2. The three flow ports of the fourth three-way valve 12 are respectively connected to the input port of the discharge compressor 4-1, the fluidized bed gas output port C2 of the cold storage fluidized bed 2-4, and the input port of the electric storage compressor 3-1.

[0062] The power storage heat regeneration device 7 is provided with a first heat exchange channel and a second heat exchange channel for heat exchange with each other. The first heat exchange channel is connected in series between the second three-way valve 10 and the input port of the power storage expander 3-2; the second heat exchange channel is connected in series between the fourth three-way valve 12 and the input port of the power storage compressor 3-1. Therefore, the power storage heat regeneration device 7 can reduce the temperature difference between the gas input to the power storage compressor 3-1 and the power storage expander 3-2 through non-contact countercurrent heat exchange of gas during the power storage process, fully utilizing waste heat and waste cooling to preheat the compressor inlet gas and precool the expander inlet gas, thereby improving the system's power storage efficiency.

[0063] The dust removal module includes a first dust collector 5 and a second dust collector 6. The first dust collector 5 is provided between the second three-way valve 10 and the fluidized bed gas outlet C2 of the heat storage fluidized beds 1-4. The second dust collector 6 is provided between the fourth three-way valve 12 and the fluidized bed gas outlet C2 of the cold storage fluidized beds 2-4.

[0064] During the electricity storage process, the output port of the electricity storage compressor 3-1, the heat storage moving bed 1-2, the heat storage fluidized bed 1-4, the first dust collector 5, the first heat exchange channel in the electricity storage heat recovery device 7, the electricity storage expander 3-2, the cold storage moving bed 2-2, the cold storage fluidized bed 2-4, the second dust collector 6, the second heat exchange channel in the electricity storage heat recovery device 7, and the input port of the electricity storage compressor 3-1 are connected in sequence to form an electricity storage gas circulation loop, and the remaining gas paths are disconnected.

[0065] At the same time, the energy storage particles in the heat storage and heat exchange module 1 and the cold storage and heat exchange module 2 are all along the material energy storage path ( Figure 1 The red solid line path in the figure) is used for transportation, and the material energy release path ( Figure 1 The blue curve path in the figure) remains disconnected and stopped, specifically: the energy storage particles in the third silo enter the fluidized bed, the energy storage particles in the fluidized bed enter the second silo, the energy storage particles in the second silo enter the moving bed, and the energy storage particles in the moving bed enter the first silo; in this process, the external input electric energy drives the electric storage compressor 3-1 to operate, the electric storage compressor 3-1 compresses the gas to increase the temperature, and the heat in the heated gas is exchanged to the energy storage particles in the heat storage and heat exchange module 1; the electric storage expander 3-2 expands the gas to cool it down, and the output kinetic energy is provided to the electric storage compressor 3-1, and the cold in the cooled gas is exchanged to the energy storage particles in the cold storage and heat exchange module 2.

[0066] During the discharge process, the output port of the discharge compressor 4-1, the heat storage moving bed 1-2, the heat storage fluidized bed 1-4, the first dust collector 5, the discharge expander 4-2, the cold storage moving bed 2-2, the cold storage fluidized bed 2-4, the second dust collector 6, and the input port of the discharge compressor 4-1 are connected in sequence to form a discharge gas circulation loop, and the other gas paths are disconnected. At the same time, the energy storage particles in the heat storage heat exchange module 1 and the cold storage heat exchange module 2 are all along the material energy release path ( Figure 2 The red solid line path in the figure) transports the material and energy storage path ( Figure 2 The blue curve path in the figure) remains disconnected and stopped, specifically: the energy storage particles in the first silo enter the fluidized bed, the energy storage particles in the fluidized bed enter the second silo, the energy storage particles in the second silo enter the moving bed, and the energy storage particles in the moving bed enter the third silo; in this process, the gas absorbs heat from the energy storage particles in the heat storage and heat exchange module 1 and then releases heat and expands in the discharge expander 4-2. The kinetic energy output by the discharge expander 4-2 simultaneously drives the discharge compressor 4-1 and the generator 4-3 to operate; the generator 4-3 outputs electrical energy to the outside; the gas output by the discharge expander 4-2 enters the cold storage and heat exchange module 2, absorbs cold energy and cools down, and then is compressed by the discharge compressor 4-1 and re-enters the heat storage and heat exchange module 1 for heat exchange, completing the cycle.

[0067] In some embodiments, the air inlet velocity into the fluidized bed is controlled during both the energy storage and energy release processes. For a moving bed, the designed air inlet velocity (the average velocity in the chamber, because the gas density will change with temperature changes) is controlled within a range of 0.2 to 0.5. v 0, preferably 0.3 v 0, where v 0 is the critical fluidization velocity of the energy storage particles. This value is a conservative value widely adopted in the industry for typical particle materials such as alumina, ensuring a safe and efficient heat transfer process.

[0068] For fluidized bed, the air inlet velocity is controlled at 1.2 v 0~1.5 v 0 (preferably 1.2 v 0), where v 0 is the critical fluidization velocity of the energy storage particles. This improves the heat transfer efficiency while minimizing the pressure loss, thereby ensuring the overall efficiency of the heat pump energy storage system.

[0069] In some embodiments, the circulating gas medium is a mixture of any one or more of air, argon, and helium.

[0070] In some embodiments, the energy storage particles are made of a mixture of any one or more of gravel, metal particles, and Al2O3 particles.

[0071] In some embodiments, the fluidized bed has strong adaptability to feed materials, and can accommodate both fine and coarse particles; the particle size of the energy storage particles can be selected within the range of 0.1 mm to 5 mm.

[0072] The working method of the heat pump power storage system provided in this embodiment includes a power storage method and a discharge method.

[0073] The process of the electricity storage method is as follows: In the initial state, the second heat storage stack silo 1-3 and the third heat storage stack silo 1-5 are filled with energy storage particles, and the first heat storage stack silo 1-1 is empty; the second cold storage stack silo 2-3 and the third cold storage stack silo 2-5 are filled with energy storage particles, and the first cold storage stack silo 2-1 is empty.

[0074] The gas flow path is switched by switching the control module, so that the storage gas circulation loop is open and the other gas paths are disconnected. External power is input to the motor 3-3, which drives the storage compressor 4-1 to compress the gas and drives the gas to circulate along the storage gas circulation loop. The flow rate of the gas input to the fluidized bed is v Controlled at 1.2 v 0~1.5 v 0 (preferably 1.2 v 0); among them, v0 is the critical fluidization velocity of energy storage particles.

[0075] The particle transfer units in the heat storage and heat exchange module 1 and the cold storage and heat exchange module 2 transfer the energy storage particles along the material energy storage path ( Figure 1 The solid red line path in the figure is used for transport.

[0076] In the above-mentioned electricity storage process, the gas cycle is as follows: The gas circulation loop is as follows: (1) The electric storage compressor 4-1 discharges high-temperature gas at 520°C into the heat storage moving bed 1-2, where it undergoes the first heat exchange with the energy storage particles in the heat storage moving bed 1-2. This process controls the discharge temperature to a set value, such as 500°C. The gas output from the heat storage moving bed 1-2 enters the heat storage fluidized bed 1-4 for the second heat exchange. This process controls the exhaust temperature of the heat storage fluidized bed 1-4 to a set value, such as 210°C. After two heat exchanges, the external input electrical energy is stored in the form of heat energy through the heat storage moving bed 1-2 and the heat storage fluidized bed 1-4 into the energy storage materials in the first heat storage stack silo 1-1 and the second heat storage stack silo 1-3. The gas output from the heat storage fluidized bed 1-4 is filtered by the first dust collector 5 and then enters the electric storage cycle regenerator, where it is cooled to 10°C by heat exchange and then output to the electric storage expander 3-2.

[0077] The heat storage moving bed 1-2 performs countercurrent heat exchange to improve the energy storage quality; the particles in the heat storage fluidized bed 1-4 enter a fluidized state under the action of the airflow to improve the heat exchange efficiency.

[0078] (2) After the gas is expanded and cooled in the electric storage expander 3-2, it enters the cold storage moving bed 2-2 through the third three-way valve 11 and undergoes the first heat exchange with the energy storage particles in the cold storage moving bed 2-2. This process controls the discharge temperature to a set value, such as -100°C. The gas output from the cold storage moving bed 2-2 enters the cold storage fluidized bed 2-4 for the second heat exchange. This process controls the exhaust temperature to a set value, such as -5°C. After two heat exchanges, the cold energy generated by the gas expansion is stored in the energy storage materials in the first cold storage stack silo 2-1 and the second cold storage stack silo 2-3 through the cold storage moving bed 2-2 and the cold storage fluidized bed 2-4. The gas output from the cold storage fluidized bed 2-4 is filtered by the second dust collector 6 and enters the electric storage cycle regenerator. The heat exchange raises the temperature to 195°C and is then output to the electric storage compressor 4-1, forming a closed cycle. The cold storage moving bed 2-2 performs countercurrent heat exchange to improve the energy storage quality; the particles in the cold storage fluidized bed 2-4 enter a fluidized state under the action of airflow to improve the heat exchange efficiency.

[0079] In the above-mentioned electricity storage process, the energy storage particles cycle as follows: In the heat storage and heat exchange module, the energy storage particles heat up in moving bed 1-2 through countercurrent heat exchange with the gas. In fluidized bed 1-4, the particles enter a fluidized state, where their temperature increases through fluidized heat exchange. Because the high-temperature gas enters moving bed 1-2 before entering fluidized bed 1-4, creating a cascade heat exchange process, the temperature of the energy storage particles in moving bed 1-2 is higher than that in fluidized bed 1-4. After the temperature of the energy storage particles in moving bed 1-2 reaches the set value (500°C), they are transferred to the first thermal storage silo 1-1 for storage. The energy storage particles in second thermal storage silo 1-3 (200°C) are added to moving bed 1-2. After the temperature of the energy storage particles in fluidized bed 1-4 increases, they are transferred to the second thermal storage silo 1-3 for storage. The energy storage particles in third thermal storage silo 1-5 (100°C) are added to fluidized bed 1-4.

[0080] In the cold storage and heat exchange module, the energy storage particles cool in the cold storage moving bed 2-2 through countercurrent heat exchange with the gas. In the cold storage fluidized bed 2-4, the energy storage particles enter a fluidized state, where their temperature is lowered through fluidized heat exchange. Because the low-temperature gas enters the cold storage moving bed 2-2 first and then the cold storage fluidized bed 2-4, a cascade heat exchange occurs, resulting in a lower temperature for the energy storage particles in the cold storage moving bed 2-2 than in the cold storage fluidized bed 2-4. After the temperature of the energy storage particles in the cold storage moving bed 2-2 drops to the set value (-100°C), they are transferred to the first cold storage silo 2-1 for storage. The energy storage particles (0°C) in the second cold storage silo 2-3 are added to the cold storage moving bed 2-2. After the temperature of the energy storage particles in the cold storage fluidized bed 2-4 drops, they are transferred to the second cold storage silo 2-3 for storage. The energy storage particles (30°C) in the third cold storage silo 2-5 are added to the cold storage fluidized bed 2-4.

[0081] The above-mentioned power storage process converts the input electricity into heat and cold, which are stored in high-temperature energy storage materials and low-temperature energy storage materials respectively, converting electrical energy into heat / cold energy storage.

[0082] The process of the discharge method is as follows: In the initial state, the first heat storage stack silo 1-1 and the second heat storage stack silo 1-3 are filled with energy storage particles, and the third heat storage stack silo 1-5 is empty; the first cold storage stack silo 2-1 and the second cold storage stack silo 2-3 are filled with energy storage particles, and the third cold storage stack silo 2-5 is empty.

[0083] The gas flow path is switched by switching the control module, so that the discharge gas circulation loop is open and the other gas paths are disconnected. During the startup phase, external power is required to start the discharge compressor 4-1, so that the gas circulates along the discharge gas circulation loop; after the cycle is established and the gas flow rate reaches the preset speed, the external power input to the discharge compressor 4-1 is cut off; the discharge compressor 4-1 continues to operate under the drive of the discharge expander 4-2; at the same time, the particle transfer units in the heat storage and heat exchange module 1 and the cold storage and heat exchange module 2 both transfer the energy storage particles along the material energy release path ( Figure 2 The solid red line path in the figure is used for transport.

[0084] In the above-mentioned discharge process, the gas circulation and energy storage particle circulation processes are similar to the power storage process.

[0085] The gas cycle is as follows: The gas passes through the first three-way valve 9 from the outlet of the discharge compressor 4-1 (100°C) and enters the heat storage moving bed 1-2, where it undergoes a first heat exchange with the solid particles from the second heat storage silo 1-3. It then enters the heat storage fluidized bed 1-4 and undergoes a second heat exchange with the solid particles from the first heat storage silo 1-1. The gas outlet temperature is controlled to be a set value (490°C). After passing through the second three-way valve 10, the gas enters the discharge expander 4-2 to expand and perform work. After the temperature drops to 180°C, it passes through the third three-way valve 11 and enters the cold storage moving bed 2-2, where it undergoes a first heat exchange with the solid particles from the second cold storage silo 2-3. After the temperature drops, it enters the cold storage fluidized bed 2-4 and undergoes a second heat exchange with the solid particles from the first cold storage silo 2-1. After the temperature drops to the target temperature (-90°C), the gas passes through the second dust collector 6 and then the fourth three-way valve 12 to enter the discharge compressor, completing the thermodynamic cycle.

[0086] The particle cycle is as follows: In the heat storage and heat exchange module, the energy storage particles (500°C) in the first heat storage silo 1-1 enter the heat storage fluidized bed 1-4 to release heat. The temperature is reduced to 495°C through fluidized heat exchange before being added to the second heat storage silo 1-3 (initial 200°C). This residual heat is fully replenished by the agitator 8 into the energy storage particles in the second heat storage silo 1-3. The energy storage particles in the second heat storage silo 1-3 enter the heat storage moving bed 1-2, where they release heat in countercurrent with the gas. After the temperature is reduced to 100°C, they are then transferred to the third heat storage silo 1-5 for storage.

[0087] In the cold storage module, the energy storage particles (-100°C) in the first cold storage silo 2-1 enter the cold storage fluidized bed 2-4 to release cold, where their temperature rises to -95°C through fluidized heat exchange. The particles are then added to the second cold storage silo 2-3 (initial 0°C). This excess cold is then added to the energy storage particles in the second cold storage silo 2-3 via agitator 8. The energy storage particles in the second cold storage silo 2-3 enter the cold storage moving bed 2-2, where they release heat in countercurrent with the gas, raising their temperature to 30°C before entering the third cold storage silo 2-5 for storage.

[0088] Through the moving bed and fluidized bed dual-bed heat exchange system, the heat and cold stored in the power storage process are transferred to the gas working fluid. The temperature difference between the high-temperature and low-temperature heat storage materials is used to drive the gas working fluid to complete the thermodynamic cycle, output electrical energy to the outside, and convert heat / cold energy into electrical energy.

[0089] The heat stored in the heat storage and heat exchange module is released, driving the generator to operate and output electrical energy.

[0090] In some embodiments, both the moving bed and the fluidized bed are designed to be cylindrical. The diameter of the moving bed is larger than that of the fluidized bed. When designing, both storage and discharge should be considered, and the larger value should be taken into account. Taking the storage heat pump module as an example: When designing the diameter and height of the moving bed, it is assumed that alumina with a particle size of 1 mm is used as the heat storage particle, air is used as the gas working medium, the moving bed gas inlet and outlet temperatures Tgi / Tgo=520 / 320℃, the solid phase inlet and outlet temperatures Tsi / Tso=200 / 500℃, and the gas flow rate Qg=3m 3 / s.

[0091] According to the Wen&Yu formula, the critical fluidization velocity Umf is calculated as: Umf=(ρs-ρg)g(dp)2 / (1650ų)=0.55m / s Where ρg is the air density at an average temperature of 420°C, which is 0.524 kg / m 3 ; ρs is the density of alumina at an average temperature of 420°C, which is 3500 kg / m 3 dp is the particle size, which is 1 mm; g is the acceleration of gravity; ų is the air viscosity at an average temperature of 420 °C, which is 3.6x10 -5 Pa·s.

[0092] Calculate the operating gas velocity of the moving bed: Uop = 0.3 × Umf = 0.17 m / s The expressions for the cross-sectional area A and diameter D of the moving bed are as follows: A=Qg / Uop=17.65m 2 D=(4A / π) 0.5 =4.74m When designing the diameter and height of the fluidized bed, the internal air flow velocity should be slightly higher than the critical fluidization velocity, but lower than the carry-out velocity (generally more than 5 times the critical fluidization velocity). 1.2 to 1.5 times the critical fluidization velocity is preferred. At the same time, both storage and discharge operating conditions should be calculated, and the height and diameter should take the larger value.

[0093] Assume that alumina with a particle size of 1mm is used as the heat storage particle, air is the gas working medium, the fluidized bed gas inlet and outlet temperatures Tgi / Tgo=320 / 210℃, the solid phase inlet and outlet temperatures Tsi / Tso=100 / 200℃, and the gas flow rate Qg=3m 3 / s.

[0094] According to the Wen&Yu formula, the critical fluidization velocity is calculated: Umf'=(ρs'-ρg')g(dp)2 / (1650ų')=0.71m / s Where ρs' is the air density at an average temperature of 265°C, which is 0.655 kg / m 3 ρg' is the density of alumina at an average temperature of 265°C, which is 3500 kg / m 3 dp is the particle size, which is 1 mm; g is the acceleration of gravity; ų' is the air viscosity at an average temperature of 265 °C, which is 2.88x10 -5 Pa·s.

[0095] Calculate the operating gas velocity of the fluidized bed: Uop'=1.2×Umf'=0.85m / s The expressions for the cross-sectional area A' and diameter D' of the fluidized bed are as follows: A'=Qg / Uop=3.53m 2 D'=(4A / π) 0.5 =2.12m In some embodiments, the stacking bin is designed to be conical. To ensure smooth material flow, the height-to-diameter ratio is 2:3, the effective volume is selected to be 4 hours of energy storage material, and sufficient redundancy is considered.

[0096] Effective volume calculation example: Assume that alumina with a particle size of 1mm is used as the heat storage particle, air is the gas working medium, the moving bed gas inlet and outlet temperatures Tgi / Tgo=520 / 320℃, the solid phase inlet and outlet temperatures Tsi / Tso=200 / 500℃, and the gas flow rate Qg=3m 3 / s.

[0097] Calculate solid mass flow rate: Ms=Qg·ρg''·Cp,g·δTg / (Cp,s·δTs)=1.184kg / s The volume of the first silo is based on a 4-hour capacity, taking into account the typical dense packing value of 0.35 for the particle gap and the redundancy coefficient of 1.5. The volume V of the first silo is as follows: V=1.5×4×3600×Ms / ρs'' / (1-0.35)=11.2m 3 Where ρg'' is the air density at an average temperature of 420°C, which is 0.524 kg / m 3 ; ρs'' is the density of alumina at an average temperature of 420℃, which is 3500kg / m 3 ; Cp,g is the specific heat of air at an average temperature of 420℃, which is 1.13kJ / (kg·K); Cp,s is the solid density at an average temperature of 420℃, which is 1kJ / (kg·K); δTg is the gas temperature difference, which is 200℃; δTs is the solid temperature difference, which is 300℃.

[0098] This embodiment provides a heat pump energy storage system and control method based on novel fluidized bed heat storage technology. This novel "dual-bed, three-compartment" fluidized bed system overcomes significant drawbacks of fluidized bed energy storage technology in heat pump energy storage systems. On the one hand, it effectively utilizes moving bed technology for countercurrent heat exchange, achieving high-quality heat storage and a large gas inlet and outlet temperature differential (fully absorbing gas heat). On the other hand, it leverages the enhanced heat exchange, continuous operation, and precise temperature control characteristics of fluidized bed technology to improve the heat exchange efficiency and energy storage density of the heat and energy storage system, ensuring stable parameters of the heat pump energy storage system and maintaining high storage and discharge efficiency.

Claims

1. A composite gradient heat pump power storage system based on a double-bed three-compartment structure, comprising a heat storage and heat exchange module (1), a cold storage and heat exchange module (2), an electric storage heat pump module (3), and a discharge heat pump module (4); characterized in that: The heat storage and heat exchange module (1) and the cold storage and heat exchange module (2) each comprise two heat exchange beds and three stacking bins; the two heat exchange beds are a moving bed and a fluidized bed respectively; the three stacking bins are a first stacking bin, a second stacking bin and a third stacking bin respectively; In both the charging and discharging states, the energy storage particles maintain a conveying direction from the fluidized bed, through the second silo, to the moving bed, and the gas maintains a flow direction from the fluidized bed to the moving bed; the gas in the moving bed directly contacts the energy storage particles for countercurrent heat exchange; the energy storage particles in the fluidized bed enter a fluidized state, and the gas and the energy storage particles undergo fluidized heat exchange, so that the output airflow temperature of the fluidized bed remains stable; In the charging state, the energy storage particles in the third silo are transported to the fluidized bed; the energy storage particles output by the moving bed are transported to the first silo; in the discharging state, the energy storage particles in the first silo are transported to the fluidized bed; the energy storage particles output by the moving bed are transported to the third silo.

2. The composite gradient heat pump power storage system according to claim 1, characterized in that: The electricity storage heat pump module (3) includes an electricity storage compressor (3-1), an electricity storage expander (3-2) and an electric motor (3-3); the discharge heat pump module (4) includes an electricity release compressor (4-1), an electricity release expander (4-2) and a generator (4-3); the rotating shafts of the electricity storage compressor (3-1) and the electricity storage expander (3-2) are coaxially fixed and connected to the output shaft of the electric motor (3-3); the rotating shafts of the electricity release compressor (4-1) and the electricity release expander (4-2) are coaxially fixed and connected to the input shaft of the generator (4-3).

3. The composite gradient heat pump power storage system according to claim 2, characterized in that: The gas outlet of the fluidized bed is connected to a dust collector.

4. The composite gradient heat pump power storage system according to claim 2, characterized in that: In the electricity storage state, the output port of the electricity storage compressor (3-1), the moving bed and the fluidized bed in the heat storage and heat exchange module (1), the electricity storage expander (3-2), the moving bed and the fluidized bed in the cold storage and heat exchange module (2), and the input port of the electricity storage compressor (3-1) are connected in sequence to form an electricity storage gas circulation loop; In the discharge state, the output port of the discharge compressor (4-1), the moving bed in the heat storage and heat exchange module (1), the fluidized bed, the discharge expander (4-2), the moving bed in the cold storage and heat exchange module (2), the fluidized bed, and the input port of the discharge compressor (4-1) are connected in sequence to form a discharge gas circulation loop.

5. The composite gradient heat pump power storage system according to claim 4, characterized in that: It also includes a switching control module; the switching control module includes multiple three-way valves; by controlling the conduction path of the three-way valve, the flow path of the control gas is switched between the power storage gas circulation loop and the power storage gas circulation loop.

6. The composite gradient heat pump power storage system according to claim 1, characterized in that: The gas output port and the particle input port of the moving bed are both arranged at the top; the gas input port and the particle output port of the moving bed are both arranged at the bottom.

7. The composite gradient heat pump power storage system according to claim 2, characterized in that: It also includes an electric storage heat recovery device (7); the electric storage heat recovery device (7) is provided with a first heat exchange channel and a second heat exchange channel for mutually exchanging heat; the first heat exchange channel is connected in series to the input pipeline of the electric storage expander (3-2); and the second heat exchange channel is connected in series to the input pipeline of the electric storage compressor (3-1).

8. The composite gradient heat pump power storage system according to claim 1, characterized in that: One or more gas dryers are connected to the gas pipeline connecting the heat storage and heat exchange module (1), the cold storage and heat exchange module (2), the electric storage heat pump module (3) and the discharge heat pump module (4); and a stirrer (8) for mixing the energy storage particles is provided in the second silo.

9. The composite gradient heat pump power storage system according to claim 1, characterized in that: One or more gas dryers are connected to the gas pipeline connecting the heat storage and heat exchange module (1), the cold storage and heat exchange module (2), the electricity storage heat pump module (3) and the discharge heat pump module (4).

10. A composite gradient heat pump power storage method based on a dual-bed, three-compartment structure, using the composite gradient heat pump power storage system according to claim 5, characterized in that: The method is as follows: During the electricity storage process, the switching control module controls the conduction of the electricity storage gas circulation loop; the gas is compressed and heated in the electricity storage compressor (4-1), and the gas flows along the electricity storage gas circulation loop; the heat storage heat exchange module (1) and the cold storage heat exchange module (2) both transport energy storage particles along the third pile silo, the fluidized bed, the second pile silo, the moving bed, and the first pile silo; in the moving bed, the gas and the energy storage particles exchange heat in a countercurrent manner; in the fluidized bed, the gas and the energy storage particles exchange heat in a fluidized state, so that the gas is output at a stable temperature; the energy storage particles in the fluidized bed are stored in the second pile silo after heat exchange; the energy storage particles in the moving bed are stored in the first pile silo after heat exchange, and the electrical energy is stored in the form of heat and cold; During the discharge process, the switching control module controls the conduction of the discharge gas circulation loop; the gas flows along the discharge gas circulation loop; the heat storage heat exchange module (1) and the cold storage heat exchange module (2) both transport energy storage particles along the first pile silo, the fluidized bed, the second pile silo, the moving bed, and the third pile silo; in the moving bed, the gas and the energy storage particles exchange heat in a countercurrent manner; in the fluidized bed, the gas and the energy storage particles exchange heat in a fluidized manner, so that the gas is output at a stable temperature; the energy storage particles in the fluidized bed are stored in the second pile silo after heat exchange; the energy storage particles in the moving bed are stored in the third pile silo after heat exchange; the gas with a higher temperature after heat exchange drives the electric storage expander (3-2) to perform work on the motor (3-3) to output electric energy.

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