Heat storage device and system and control method

Abstract

The invention discloses a heat storage device and system and a control method, and relates to the technical field of power system energy storage. The heat storage device comprises a heat storage body, and the outer side of the heat storage body is coated with a heat preservation layer. The heating unit is arranged in the heat accumulator and can heat the heat accumulator after being electrified; one end of the control circuit is connected with a power supply and the other end is connected with the heating unit; the adjusting unit is connected with the control circuit and can transmit signals to the control circuit and adjust the heating power of the heating unit. According to the heat storage device and system and the control method, large-scale long-time energy storage can be achieved, and the energy storage efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of power system energy storage, and in particular to a heat storage device, system and control method. Background Art

[0002] The installed capacity of renewable energy sources such as wind and solar energy has grown rapidly, and they have become an important part of the power system. However, the intermittent and random characteristics of renewable energy have brought new challenges, making the supply and demand balance of the power system more complicated and having a significant impact on the stability and economic operation of the power grid.

[0003] As one of the key means to solve the above problems, energy storage technology is becoming increasingly important. It can not only smooth out the fluctuations of renewable energy and ensure the continuity and reliability of power supply, but also provide auxiliary services such as frequency regulation and voltage support, thereby enhancing the flexibility and stability of the entire power system. The application range of energy storage systems is wide, covering all aspects of power production. From power smoothing on the power generation side to demand response on the user side, energy storage technology plays an indispensable role.

[0004] However, traditional energy storage technologies, such as pumped storage, compressed air storage and flywheel storage, cannot achieve large-scale, long-term energy storage and have low energy storage efficiency. Summary of the invention

[0005] The purpose of the present invention is to provide a heat storage device, system and control method to solve the problems existing in the above-mentioned prior art, so as to achieve large-scale long-term energy storage and improve energy storage efficiency.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] The present invention provides a heat storage device, comprising: a heat storage body, the outer side of which is coated with a heat insulation layer, the heat insulation layer is arranged outside the heat storage body, and is used to reduce heat loss and improve heat storage efficiency; a heating unit, which is arranged in the heat storage body and can heat the heat storage body after being powered on; a control circuit, one end of which is connected to a power supply and the other end is connected to the heating unit; an adjustment unit, which is connected to the control circuit and can transmit a signal to the control circuit and adjust the heating power of the heating unit, so that the adjustment unit realizes the fine adjustment of the electromagnetic heating power, and can make full use of low-price electricity for efficient heat storage during the off-peak period at night. The present invention uses the electrothermal conversion technology coupled with electromagnetic induction and high-temperature radiation, and uses the control circuit with IGBT as the core to achieve efficient heating and temperature control of the cast iron heat storage medium, which is particularly suitable for large-scale and long-term heat storage using valley electricity.

[0008] The present invention selects materials with high specific heat capacity and high density as heat storage media, such as cast iron. Such materials can store a large amount of heat energy in a small space. Cast iron not only has a high heat capacity, but also has good thermal conductivity and high temperature resistance, which makes it an ideal heat storage material. Multiple cast iron bodies are closely arranged to form a heat storage module, which further increases the heat storage capacity per unit volume.

[0009] Secondly, the use of efficient heating technology, such as electromagnetic induction heating, can quickly convert electrical energy into heat energy and store it in the thermal storage body. Electromagnetic induction heating is more efficient than traditional resistance heating because it generates heat directly in the thermal storage body, reducing energy loss during heat conduction. At the same time, the control circuit works in conjunction with the adjustment unit to accurately adjust the heating power as needed to ensure that the temperature of the thermal storage body is maintained within the optimal range, thereby improving energy storage efficiency.

[0010] In addition, good insulation measures are also one of the key factors to ensure heat storage. Coating a layer of efficient insulation material on the outside of the heat storage body can significantly reduce heat loss, maintain the high temperature inside the heat storage body, and extend the energy storage time. In this way, without increasing the physical size of the heat storage body, the heat storage capacity of the overall system can be effectively improved.

[0011] Preferably, the heat storage body is a block-shaped cast iron body with high magnetic permeability, a plurality of the cast iron bodies are arranged in sequence, a heating hole is opened at one end of the cast iron body, and the heating unit is arranged in the cast iron body.

[0012] Preferably, the heating unit is a coil, which is fixed in the heating hole and connected to the control circuit. The heating unit uses the principle of electromagnetic induction to cause the nonlinear changing current in the high-temperature coil to generate eddy current in the cast iron body, thereby converting electrical energy into thermal energy.

[0013] Preferably, the control circuit includes a rectifier circuit, a choke coil, a resonant capacitor and an IGBT chip; the input end of the rectifier circuit is connected to an AC power supply, and the output end is connected to the choke coil, the choke coil is connected to the resonant capacitor and the IGBT chip in turn, the IGBT chip is electrically connected to the heating unit, and the IGBT chip can receive the signal of the adjustment unit and adjust the output power to the heating unit. The IGBT chip, the rectifier circuit, the choke coil, and the resonant capacitor form an electrothermal conversion main oscillation circuit to realize power-controlled electromagnetic eddy current heating and resistance radiation heating technology; the rectifier circuit generally consists of four diodes to form a bridge rectifier, and a special rectifier module can also be used. Its main function is to convert the input AC power into unidirectional pulsating DC power, in preparation for subsequent DC-AC conversion or direct power supply to the load. Construct a square wave width control circuit, the square wave width increases, the IGBT chip path time increases, and the output power increases accordingly; the square wave width decreases, the IGBT chip path time shortens, and the output power decreases accordingly. This control method not only avoids the risk of IGBT burning caused by the ferromagnetic temperature exceeding the Curie temperature and the ferromagnetism being greatly reduced during electromagnetic eddy current heating, but also avoids the problem of burning of joints or weak parts caused by excessive current at the moment of cold start during resistive radiation heating, providing important basic technical support for high-temperature heat storage.

[0014] Square wave width control adjusts the output power by changing the duty cycle of the signal. The controller compares the actual temperature fed back by the temperature sensor with the preset temperature, calculates the required heating power, and generates the corresponding PWM signal. This signal is sent to the IGBT chip, and the IGBT quickly switches the conduction state according to the high and low levels of the signal. The longer the high level time, the higher the duty cycle, the greater the average current obtained by the heating unit, and the higher the heating power; conversely, the lower the duty cycle, the lower the heating power. The whole process forms a closed-loop control system. The temperature sensor continuously monitors and feeds back the actual temperature, and the controller continuously adjusts the duty cycle of the PWM signal to ensure that the actual temperature is close to the preset value. This control method can not only achieve precise power regulation, but also improve the response speed and control accuracy of the system. In this way, even if the volume of the heat storage body is limited, the temperature inside it can be efficiently managed and adjusted, thereby realizing large-scale heat storage.

[0015] Preferably, a temperature sensor is further included, wherein the temperature sensor is arranged in the heat storage body and connected to the adjustment unit, and the temperature sensor is used to detect the temperature inside the heat storage body and transmit the temperature signal to the adjustment unit, and adjust the output power of the control circuit accordingly to achieve closed-loop control of the temperature.

[0016] The present invention also provides a heat storage system, comprising a pipeline and the heat storage device as described above; the heat storage body is provided with a plurality of cavities arranged in parallel, the pipeline enters from the first cavity at one end of the heat storage body, and after reciprocating through the plurality of cavities in sequence, exits from the last cavity at the other end of the heat storage body, the entry end of the pipeline is connected to a water tank through a water inlet pipe and a circulating pump, and the exit end is connected to a steam turbine, and the steam turbine is connected to the water tank through a return pipe; the steam turbine is connected to the user end through a transmission line.

[0017] Preferably, the pipeline includes a first bypass and a second bypass, the second bypass reciprocates through the plurality of cavity diameters in sequence, the second bypass is provided with a first regulating valve and a second regulating valve in sequence near the first cavity diameter, the first bypass is arranged outside the heat storage body, and one end of the first bypass is connected to the second bypass located between the first regulating valve and the second regulating valve, and the other end of the first bypass is connected to the second bypass near the last cavity diameter through the first bypass valve.

[0018] Preferably, it also includes an intermediate pipeline, which is located outside the heat storage body and is provided with a second bypass valve. One end of the intermediate pipeline is connected to the second bypass located between the first regulating valve and the second regulating valve, and the other end is connected to the second bypass located at any cavity diameter between the first cavity diameter and the last cavity diameter.

[0019] Preferably, a desuperheater is provided at a position of the pipeline close to the steam turbine.

[0020] The present invention also provides a heat storage system control method, comprising the steps of: a temperature sensor detecting the temperature of the heat storage body and transmitting the signal to a regulating unit;

[0021] When the temperature inside the heat storage body is lower than the preset temperature threshold, the regulating unit increases the heating power through the control circuit to increase the heat storage capacity of the heat storage body;

[0022] When it is detected that the temperature inside the heat storage body is higher than a preset temperature threshold, the regulating unit reduces the heating power through the control circuit to reduce the heat storage amount of the heat storage body;

[0023] When it is detected that the temperature inside the heat storage body reaches a predetermined temperature value, the regulating unit controls the heating unit to stop working through the control circuit.

[0024] Compared with the prior art, the present invention has achieved the following technical effects:

[0025] The heat storage device provided by the present invention adopts a cast iron body with high magnetic permeability, which has a better heat storage effect. The outside of the heat storage device is coated with a thermal insulation layer to avoid heat loss and can store energy for a long time. When needed, the energy stored in the heat storage device can heat the liquid to form steam, and the steam is transported to the steam turbine to generate electricity, thereby realizing the release and utilization of energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 is a schematic diagram of a heat storage system of the present invention;

[0028] Figure 2 is a schematic diagram of the heat storage device and the regulating unit of the present invention;

[0029] Figure 3 It is a schematic diagram of the cast iron body assembly and coil arrangement of the present invention;

[0030] Figure 4 is a schematic diagram of a cast iron body of the present invention;

[0031] Figure 5 is a schematic diagram of the coil of the present invention;

[0032] Figure 6 It is a 5h average temperature distribution curve of a single cast iron body of the heat storage body of the present invention.

[0033] In the figure: 1-heat storage body; 11-cast iron body; 111-cavity diameter; 12-insulation layer; 13-pipeline; 131-first regulating valve; 132-second regulating valve; 133-first bypass valve; 134-second bypass valve; 135-first bypass; 136-second bypass; 14-temperature sensor; 2-heating unit; 21-coil; 22-desuperheater; 3-control circuit; 31-IGBT chip; 32-rectifier circuit; 33-choke coil; 34-resonant capacitor; 4-regulating unit; 5-steam turbine; 6-user. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] The purpose of the present invention is to provide a heat storage device, system and control method to solve the problems existing in the above-mentioned prior art, so as to achieve large-scale long-term energy storage and improve energy storage efficiency.

[0036] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0037] Energy storage technology can not only smooth out the fluctuations of renewable energy and ensure the continuity and reliability of power supply, but also provide auxiliary services such as frequency regulation and voltage support, thereby enhancing the flexibility and stability of the entire power system. The application range of energy storage systems is wide, covering all aspects of power production, from power smoothing on the power generation side to demand response on the user side, energy storage technology plays an indispensable role.

[0038] However, traditional energy storage technologies, such as pumped storage, compressed air storage and flywheel storage, face the problems of high cost, low efficiency and slow response speed in large-scale and long-term energy storage. In order to solve this problem, the first purpose of the present invention is to provide a thermal storage device that converts electrical energy into thermal energy for storage, which can realize long-term and large-scale energy storage, such as Figure 1 to Figure 5 As shown, its structure includes a heat storage body 1, and a heat preservation layer 12 is coated on the outside of the heat storage body 1 to reduce heat loss and improve heat storage efficiency; a heating unit 2 is arranged in the heat storage body 1, and can heat the heat storage body 1 after power is turned on to realize the energy storage function; a control circuit 3 is connected to the power supply at one end and connected to the heating unit 2 at the other end; an adjustment unit 4 is connected to the control circuit 3, and can transmit a signal to the control circuit 3 and adjust the heating power of the heating unit 2, so that the adjustment unit 4 realizes the fine adjustment of the electromagnetic heating power, and can make full use of low-price electricity for efficient heat storage during the off-peak period at night. The present invention realizes efficient heating and temperature control of the heat storage medium of the heat storage body 1 through the electrothermal conversion technology coupled with electromagnetic induction and high-temperature radiation, and uses a control circuit with IGBT as the core, which is particularly suitable for large-scale and long-term heat storage using valley electricity.

[0039] Specifically, the regulating unit 4 is mainly responsible for monitoring the system status and adjusting the power of the heating unit 2 as needed to ensure that the temperature in the heat storage body 1 is maintained within the ideal range. The regulating unit 4 includes a known existing core controller (such as a microprocessor or PLC), which receives data from devices such as temperature sensors and decides how to adjust the power of the heating unit 2 based on preset known mature algorithms or control logic. The signal processing module of the controller converts the analog signal sent by the sensor into a digital signal so that the controller can read and process the data. Once the controller determines the required heating power, it sends instructions to the control circuit through the output driver module, which may be a pulse width modulation (PWM) controller or an interface circuit that communicates directly with the IGBT chip.

[0040] The connection between the regulating unit 4 and the control circuit 3 is usually achieved through electrical wiring. The regulating unit 4 calculates the required heating power based on the real-time temperature information obtained from the temperature sensor and the preset target temperature range, and then generates a corresponding control signal to transmit to the IGBT chip in the control circuit 3. The IGBT chip changes its conduction time according to the received signal, thereby accurately adjusting the electric energy supplied to the heating unit 2 to control the heating process. In this way, the regulating unit 4 generates appropriate control instructions by monitoring and analyzing the temperature, and executes these instructions through the control circuit to form a closed-loop control system, which helps to improve the energy storage efficiency and ensure the safe operation of the entire system.

[0041] In order to improve the heat storage efficiency, the heat storage body 1 of this embodiment is a block-shaped cast iron body 11, which has a high magnetic permeability. Multiple cast iron bodies 11 are arranged in sequence to form a complete heat storage body module. A heating hole is opened at one end of the cast iron body 11. The heating unit 2 uses a coil 21, which is a high-temperature coil and can achieve normal operation at high temperatures. The coil 21 is fixed in the heating hole, and the coil 21 is connected to the control circuit 3. The heating unit 2 uses the principle of electromagnetic induction to make the nonlinear changing current in the high-temperature coil generate eddy currents in the cast iron body 11. These eddy currents encounter the cast iron body 11 and generate heat based on the resistance of the cast iron body 11 material, thereby converting electrical energy into thermal energy. In this case, the coil is usually made of high-temperature resistant materials and is designed to withstand high-temperature working environments; by using the cast iron body 11 as a heat storage medium and combining efficient electromagnetic heating technology, a fast and stable heat storage process can be achieved, the heat storage efficiency can be improved, and the operating cost can be reduced.

[0042] After the inside of the heat storage body 1 is heated to a certain temperature by electromagnetic induction, it begins to radiate heat to the outside in the form of thermal radiation. As the temperature rises, the surface of the heat storage body 1 will emit more energy in the form of electromagnetic waves such as infrared rays. In the heat storage device, once the cast iron body 11 is heated to a sufficiently high temperature, it will become an effective heat radiation source, transferring heat to the surrounding environment or a specific target. The electromagnetic induction heating of the present invention first quickly increases the temperature of the heat storage body 1. When the heat storage body 1 reaches a certain temperature, it begins to significantly release heat by thermal radiation, and heats the medium in the pipes passing through the heat storage body 1 by radiation heating. This means that the heat storage body 1 not only heats water or other media by contact heat transfer, but also transfers energy to the surrounding space by radiation. In order to effectively combine these two heating methods, the present invention uses materials with high magnetic permeability and good thermal conductivity (such as cast iron), which can ensure high efficiency of electromagnetic induction heating and effectively store and release heat. In addition, the shape and layout of the heat storage body 1 also need to be optimized so that the thermal radiation can evenly cover the object to be heated. Good insulation reduces unnecessary heat loss, allowing more heat to be used to directly heat the target medium or to be effectively transferred by radiation.

[0043] In a specific embodiment, the control circuit of the intelligent control system 3It includes a rectifier circuit 32, a choke coil 33, a resonant capacitor 34 and an IGBT chip 31; the input end of the rectifier circuit 32 is connected to an AC power source, and the output end is connected to a choke coil 33, the choke coil 33 is connected to a resonant capacitor 34 and an IGBT chip 31 in turn, the IGBT chip 31 is electrically connected to the heating unit 2, and the IGBT chip 31 can receive a signal from the adjustment unit 4 and adjust the output power to the heating unit 2. The AC power source is converted into DC power by the rectifier circuit 32, and the rectifier circuit 32 is usually composed of a diode bridge, which is used to convert the AC power provided by the power grid into DC power and provide a stable working voltage for the subsequent circuit. The DC power output from the rectifier circuit 32 will pass through the choke coil 33. The function of the choke coil 33 is filtering, that is, smoothing the fluctuations in the current. At the same time, it can also limit the rate of change of the current, and it also has a certain effect on preventing electromagnetic interference. After the choke coil 33, a resonant capacitor 34 will be added to the circuit. The resonant capacitor 34 and the choke coil 33 together form an LC resonant circuit, which can produce a resonance effect at a specific frequency, thereby improving the efficiency of electromagnetic heating. The specific value of the resonant capacitor needs to be selected according to the actual application requirements to achieve the best resonance effect. Intelligent control systems are mature technologies used to achieve intelligent management and control of heat storage devices. Sensors such as temperature sensors monitor the temperature inside the heat storage body in real time. The controller (usually a microprocessor or PLC) receives these data and generates corresponding control signals according to the preset control algorithm. The control circuit includes components such as rectifier circuits, choke coils, resonant capacitors and IGBT chips, which are responsible for converting the control signals sent by the controller into actual power output and adjusting the working state of the heating unit. Actuators such as IGBT chips adjust the power output of the heating unit according to the instructions of the control circuit.

[0044] During operation, the DC power after the above treatment will be sent to the IGBT chip 31. IGBT is an insulated gate bipolar transistor, which is a power semiconductor device that can switch quickly to achieve precise control of the heating power. The working state (on or off) of the IGBT is controlled by the pulse signal sent by the control circuit 3, and then the power supplied to the load (such as the heating element) is adjusted. The adjustment unit 5 realizes the fine adjustment of the electromagnetic heating power, usually running during the low period at night, and the IGBT chip is directly connected to the adjustment unit. As the core control element of the control circuit 3, the IGBT realizes the fine adjustment of the heating power by receiving the control signal (usually a PWM signal) from the adjustment unit 4. In other words, the adjustment unit 4 indirectly controls the power output of the heating system by changing the duty cycle of the signal sent to the IGBT. The design of the entire control circuit 3 follows the order from power input to final power output, and the components are closely connected to each other to jointly complete the power adjustment task in the electromagnetic heating process.

[0045] In order to achieve controllable temperature of the heat storage body 1, a temperature sensor 14 is provided in the heat storage body 1. The temperature sensor 14 is connected to the adjustment unit 4. The temperature sensor 14 is used to detect the temperature inside the heat storage body 1 and transmit the temperature signal to the adjustment unit 4, and adjust the output power of the control circuit 3 accordingly to achieve closed-loop control of the temperature. The adjustment unit 4 decides how to adjust the heating power according to the temperature signal provided by the temperature sensor 14. Specifically, the temperature sensor 14 is installed in the heat storage body 1, monitors the temperature of the heat storage body 1 in real time, and converts the temperature data into an electrical signal. These signals are transmitted to the adjustment unit 4, and the control algorithm (such as a PID controller) built into the adjustment unit 4 processes and analyzes these data. The control algorithm is a known prior art and does not belong to the protection scope of the present invention, so it will not be described in detail. The adjustment unit 4 calculates the required heating power adjustment amount based on the difference between the current temperature and the preset target temperature.

[0046] The regulating unit 4 generates corresponding control signals (such as PWM signals) and sends these signals to the control circuit 3. The IGBT chip or other switching device in the control circuit 3 adjusts the power output of the heating unit 2 according to the received control signal. If the heating power needs to be increased, the regulating unit 4 will send a PWM signal with a higher duty cycle; if the heating power needs to be reduced, a PWM signal with a lower duty cycle will be sent. Therefore, the whole process is that the temperature sensor 14 detects the temperature and transmits the signal to the regulating unit 4, the regulating unit 4 calculates the required heating power adjustment according to the temperature signal, and generates a control signal to send to the control circuit 3, and the control circuit 3 adjusts the power output of the heating unit 2 according to these signals, thereby realizing accurate control of the temperature of the heat storage body 1. In this way, the regulating unit 4 is responsible for decision-making and generating control instructions, while the control circuit 3 is responsible for executing these instructions to ensure that the heating power is accurately adjusted.

[0047] The energy storage systems known to the inventors are often unable to meet the needs of modern power systems for fast response and high-precision frequency control in terms of the rotational inertia and primary frequency regulation capabilities required by the power system.

[0048] Rotational inertia is the basis for the stable operation of the power system. It can buffer instantaneous power fluctuations and avoid drastic changes in frequency. With the reduction of the proportion of traditional synchronous generators, the total inertia of the system has decreased, posing a threat to the frequency stability and dynamic performance of the power system. Primary frequency regulation is an important mechanism for the power system to automatically adjust the frequency deviation. It requires the energy storage system to respond quickly to frequency changes, adjust the output power in time, and maintain the system frequency within the allowable range.

[0049] Therefore, the development of new energy storage technologies, especially energy storage systems that can provide rotational inertia and primary frequency regulation capabilities in large-scale, long-term energy storage, has become an urgent problem to be solved in the current power industry. Based on this, the second purpose of the present invention is to propose an energy storage system customized for the needs of the power system, aiming to improve the rotational inertia and primary frequency regulation capabilities. When the grid frequency fluctuates, the adjustment unit 4 in the present invention can quickly detect these changes and adjust the power output of the heating unit 2 through the control circuit 3. For example, when the frequency drops, the heating power can be reduced to release more electrical energy to supply the grid; conversely, when the frequency rises, the heating power can be increased to absorb excess electrical energy, thereby achieving improved rotational inertia and primary frequency regulation capabilities. The heat storage system includes a pipeline and the above heat storage device; a plurality of parallel cavities 111 are provided on the heat storage body, the pipeline enters from the first cavity 111 at one end of the heat storage body 1, and after reciprocating through the plurality of cavity 111 in sequence, exits from the last cavity 111 at the other end of the heat storage body 1, the pipeline entry end is connected to the water tank through the water inlet pipe and the circulating pump, and the exit end is connected to the steam turbine 5, and the steam turbine 5 is connected to the water tank through the return pipe; the steam turbine 5 is connected to the user 6 through the transmission line, during the off-peak period at night, the AC power source heats the heat storage body 1 to realize the conversion of electrical energy into thermal energy and realize energy storage, during the peak period during the day, liquid can be introduced into the pipeline, the liquid is heated to high-temperature steam when flowing through the heat storage body, the steam is transported to the steam turbine 5 to realize power generation, and the electricity is transported to the user 6, realizing the utilization of the energy stored in the heat storage body 1.

[0050] In order to enable the heat storage body 1 to fully contact with the pipeline, improve the heating efficiency of the medium in the pipeline, and be able to adjust the heating degree of the medium in the pipeline at any time as needed, the pipeline of this embodiment includes a first bypass 135 and a second bypass 136, the second bypass 136 sequentially reciprocates through multiple cavity diameters 111, and the second bypass 136 is sequentially provided with a first regulating valve 131 and a second regulating valve 132 near the first cavity diameter 111. The first bypass 135 is arranged outside the heat storage body 1, and one end of the first bypass 135 is connected to the second bypass 136 located between the first regulating valve 131 and the second regulating valve 132, and the other end of the first bypass 135 is connected to the second bypass 136 near the last cavity diameter 111 through the first bypass valve 133. The steam flow is controlled by controlling the opening of the first regulating valve 131. The circulating pump transports the liquid to the second bypass 136 through the water inlet pipe. The first regulating valve 131 and the second regulating valve 132 are opened, and other valves are closed, so that the liquid completely flows through the second bypass 136 and is then output to the steam turbine. The liquid in the pipeline can fully contact with the heat storage body to absorb heat.

[0051] When a higher steam temperature is not required, the steam flow direction is controlled by closing the second regulating valve 132 and opening the first regulating valve 131 and the first bypass valve 133, so that the liquid in the pipeline is heated by the first cavity 111 of the thermal storage body 1, enters the first bypass 135 outside the thermal storage body 1, and then directly enters the steam turbine 5 after passing through the last cavity 111 of the thermal storage body 1, so as to achieve fine temperature control, that is, under the high temperature condition of 700°C, by opening the first bypass valve 133 and closing the second regulating valve 132, the steam is guided to bypass the thermal storage body 1 to avoid overheating. When the temperature drops to 500°C, by closing the first bypass valve 133 and opening the first regulating valve 131 and the second regulating valve 132, the steam flows through the main body of the thermal storage body 1 to maximize the absorption of heat.

[0052] In order to further control the temperature, an intermediate pipeline is further provided in a preferred embodiment. The intermediate pipeline is located outside the heat storage body 1, and a second bypass valve 134 is provided on the intermediate pipeline 1. One end of the intermediate pipeline is connected to the second bypass 136 located between the first regulating valve 131 and the second regulating valve 132, and the other end is connected to the second bypass 136 located at any cavity diameter 111 between the first cavity diameter 111 and the last cavity diameter 111. By opening the first regulating valve 131 and the second bypass valve 134, and closing the second regulating valve 132 and the first bypass valve 133, the liquid in the pipeline flows through the second bypass 136 in the cavity diameter 111 of the front half of the heat storage body 1 and is heated, and then enters the second bypass 136 in the cavity diameter 111 of the rear half of the heat storage body 1 through the intermediate pipeline, that is, it does not pass through the second bypass 136 in the cavity diameter 111 in the middle of the heat storage body 1, which plays a partial heating function, thereby adjusting the temperature of the steam.

[0053] On the basis of the above scheme, the present invention also provides a heat storage system control method, comprising the following steps: the temperature sensor 14 detects the temperature of the heat storage body and transmits the signal to the regulating unit 4; when the temperature inside the heat storage body 1 is lower than a preset temperature threshold, the regulating unit 4 increases the heating power through the control circuit to increase the heat storage capacity of the heat storage body 1; when it is detected that the temperature inside the heat storage body 1 is higher than the preset temperature threshold, the regulating unit 4 reduces the heating power through the control circuit 3 to reduce the heat storage capacity of the heat storage body 1; when it is detected that the temperature inside the heat storage body 1 reaches a predetermined temperature value, the regulating unit 4 controls the heating unit 2 to stop working through the control circuit 3.

[0054] Specifically, a desuperheater 22 is further provided between the second bypass 136 and the steam turbine 5. The structure of the desuperheater 22 is a known technology and will not be described in detail. When the operating temperature of the heat storage body 1 is as high as 700°C, in order to prevent the outlet steam from being overheated due to the excessively high temperature of the heat storage body 1, the steam is introduced into the first bypass 135 by opening the first bypass valve 133 and closing the second regulating valve 131, avoiding the intervention of the desuperheater 22, thereby effectively preventing the excessive transfer of heat from the heat storage body 1 to the steam while maintaining the steam outlet temperature at the design threshold, thereby ensuring the safe and stable operation of the system.

[0055] When the operating temperature of the heat storage body 1 drops to 500°C, in order to ensure that the outlet steam can still reach the preset superheated state, at this time, the first bypass valve 133 is closed and the first regulating valve 131 is opened to allow the steam to flow through the heat storage body 1 to absorb the heat of the heat storage body to the maximum extent. At the same time, within this temperature range, the steam flow rate is finely controlled by opening the desuperheater 22 to achieve effective control of the outlet steam temperature to ensure that it meets the design requirements.

[0056] When the working temperature of the heat storage body 1 is between 500℃ and 700℃, the research focuses on realizing precise control of the steam parameters at the outlet of the heat storage body 1. In specific operation, by precisely coordinating the opening of the first bypass valve 133, the second bypass valve 134 and the first regulating valve 131, and timely activating the water spray of the desuperheater 22, the saturated steam flowing into the heat storage body 1 is diverted and the heat absorption is finely regulated, thereby realizing stable control of the outlet steam temperature of the heat storage body 1 to ensure that it always meets the design standards.

[0057] In order to effectively control the temperature of superheated steam, improve the ability of steam turbine 5 to participate in primary frequency modulation, and ensure the safety of steam turbine 5, two sets of hybrid desuperheaters 22 are set, which are respectively placed at the front end of the steam outlet and the front end of the steam turbine 5, and directly spray the steam low-temperature water into the superheated steam flow to reduce its super-high temperature, providing double insurance for the stable operation of steam turbine 5.

[0058] The heat storage body is composed of multiple cast iron bodies arranged in sequence. Figure 6 As shown, it is a 5h average temperature distribution curve of a single cast iron body of the heat storage body 1. The number of cast iron bodies 11 is relatively large and multiple cast iron bodies are distributed adjacent to each other, so that the temperature reduction area is gradually balanced by the temperature increase area, and the temperature distribution of each cast iron body 11 will eventually present a quasi-uniform distribution state. After a single cast iron body 11 is heated by the coil 21, the temperature gradually decreases from the initial time 0h, 1h, 2h, 3h, 4h and 5h, and after 5h it decreases from 700℃ to 419℃, and the temperature drop rate gradually slows down, with the temperature drop amplitude every 1h being 102.57℃, 64.5℃, 47.52℃, 36.83℃, and 29.48℃. As shown Figure 6 Shown is the 5h average temperature distribution curve of a single cast iron body.

[0059] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A heat storage device, characterized in that: include: A heat storage body, the outer side of which is coated with a heat-insulating layer; A heating unit is disposed in the heat storage body and can heat the heat storage body after being powered on; A control circuit, one end of which is connected to a power source, and the other end of which is connected to the heating unit; The regulating unit is connected to the control circuit, and can transmit a signal to the control circuit and regulate the heating power of the heating unit.

2. The heat storage device according to claim 1, characterized in that: The heat storage body is a block-shaped cast iron body, a plurality of the cast iron bodies are arranged in sequence, a heating hole is opened at one end of the cast iron body, and the heating unit is arranged in the cast iron body.

3. The heat storage device according to claim 1, characterized in that: The heating unit is a coil, the coil is fixed in the heating hole, and the coil is connected to the control circuit.

4. The heat storage device according to claim 1, characterized in that: The control circuit includes a rectifier circuit, a choke coil, a resonant capacitor and an IGBT chip; the input end of the rectifier circuit is connected to an AC power supply, and the output end is connected to the choke coil, the choke coil is connected to the resonant capacitor and the IGBT chip in sequence, the IGBT chip is electrically connected to the heating unit, and the IGBT chip can receive a signal from the adjustment unit and adjust the output power to the heating unit.

5. The heat storage device according to claim 1, characterized in that: It also includes a temperature sensor, which is arranged in the heat storage body and connected to the adjustment unit.

6. A heat storage system, characterized in that: It comprises a pipeline and a heat storage device as claimed in any one of claims 1 to 5; the heat storage body is provided with a plurality of cavities arranged in parallel, the pipeline enters from the first cavity at one end of the heat storage body, and after successively reciprocating through the plurality of cavities, exits from the last cavity at the other end of the heat storage body, the entry end of the pipeline is connected to a water tank through a water inlet pipe and a circulating pump, and the exit end is connected to a steam turbine, and the steam turbine is connected to the water tank through a return pipe; the steam turbine is connected to the user end through a transmission line.

7. The thermal storage system according to claim 6, characterized in that: The pipeline includes a first bypass and a second bypass, the second bypass reciprocates through the multiple cavity diameters in sequence, the second bypass is provided with a first regulating valve and a second regulating valve in sequence near the first cavity diameter, the first bypass is arranged outside the heat storage body, and one end of the first bypass is connected to the second bypass located between the first regulating valve and the second regulating valve, and the other end of the first bypass is connected to the second bypass near the last cavity diameter through the first bypass valve.

8. The thermal storage system according to claim 7, characterized in that: It also includes an intermediate pipeline, which is located outside the heat storage body and is provided with a second bypass valve. One end of the intermediate pipeline is connected to the second bypass located between the first regulating valve and the second regulating valve, and the other end is connected to the second bypass located at any cavity diameter between the first cavity diameter and the last cavity diameter.

9. The thermal storage system according to claim 7, characterized in that: A desuperheater is provided at a position of the pipeline close to the steam turbine.

10. A thermal storage system control method, characterized in that: Includes steps: The temperature sensor detects the temperature of the heat storage body and transmits the signal to the regulating unit; When the temperature inside the heat storage body is lower than the preset temperature threshold, the regulating unit increases the heating power through the control circuit to increase the heat storage capacity of the heat storage body; When it is detected that the temperature inside the heat storage body is higher than a preset temperature threshold, the regulating unit reduces the heating power through the control circuit to reduce the heat storage amount of the heat storage body; When it is detected that the temperature inside the heat storage body reaches a predetermined temperature value, the regulating unit controls the heating unit to stop working through the control circuit.

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