Temperature swing heat storage source water heat releasing system and control method thereof

Abstract

The application provides a control method of a variable-temperature heat storage source water heat release system, which comprises the following steps: obtaining a temperature correction value of desalted water at an outlet of a steam-water mixer, a desalted water temperature at an outlet of a heat exchanger, a measured flow of bypass desalted water of the heat exchanger, and a pressure, a temperature and a flow of the desalted water at an inlet of the desalted water; calculating a enthalpy correction value of the desalted water at the outlet of the steam-water mixer, an enthalpy value of the desalted water at the inlet of the desalted water and an enthalpy value of the desalted water or steam at the outlet of the heat exchanger; calculating a flow correction value of the bypass desalted water of the heat exchanger according to the enthalpy correction value, the enthalpy value of the desalted water, the enthalpy value of the desalted water or steam and the flow of the desalted water at the inlet; taking a deviation between the measured flow and the flow correction value as an input to perform a PID operation, obtaining a opening degree instruction change amount of a bypass flow regulating valve of the heat exchanger, adjusting the regulating valve according to the change amount, and realizing the control of the system. The application can eliminate the adverse effects caused by large inertia of the system and realize the basic function of stable heat energy output of the system.

Description

Technical Field

[0001] This application relates to the field of thermal storage systems and control technology, and in particular to a variable temperature thermal storage source water heat release system and its control method. Background Technology

[0002] Molten salt thermal energy storage is one of the most widely used thermal energy storage technologies. It stores and releases thermal energy through heat exchange between liquid molten salt and other flowing media. Because molten salt thermal energy storage is a sensible heat storage technology, the temperature of the molten salt changes continuously during system operation, altering the operating conditions of the heat exchangers and heat transfer media. The traditional solution is to use a "dual-tank" molten salt thermal energy storage technology, which determines the cold and hot end temperatures of the molten salt to ensure stable system operation. However, this solution requires a large system footprint and has low utilization of the thermal storage medium. With the continuous development of energy storage technology, its application scenarios are becoming increasingly diversified, and the industry's demand for simplified systems and stable operation is growing.

[0003] To reduce the risk of molten salt blockage in the system, "single-tank" molten salt thermal storage technology, characterized by reducing the amount of molten salt used and narrowing the flow range of molten salt, has gradually developed. In this typical system, during the heat release process, demineralized water is introduced into the molten salt heat exchanger to absorb heat and raise its temperature, or to evaporate and release heat. At this time, the temperature of the molten salt continuously decreases, causing a steam-water phase change at the system outlet, which is detrimental to the stable operation of the surrounding systems. Summary of the Invention

[0004] This application aims to at least partially address one of the technical problems in the related art.

[0005] Therefore, the first objective of this application is to propose a control method for a variable-temperature thermal energy storage water heat release system. This method solves the technical problem of unstable operation in existing molten salt-steam-water storage heat release systems due to the significant influence of molten salt temperature changes on the outlet phase and temperature of the heat exchange medium. By setting up a steam-water mixer and a bypass flow regulating valve for the heat exchanger, combined with an efficient cascade PID control strategy, the phase and temperature of the heat extraction medium during the heat release process are not affected by changes in the molten salt temperature. This achieves the basic function of stabilizing the phase and temperature of the heat exchange medium during the heat release process, minimizing interference from various internal and external factors, ensuring stable output heat energy, and facilitating the stable operation of peripheral systems.

[0006] The second objective of this application is to propose a variable-temperature thermal energy storage water-based heat release system.

[0007] The third objective of this application is to propose a computer device.

[0008] The fourth objective of this application is to provide a non-transitory computer-readable storage medium.

[0009] To achieve the above objectives, the first aspect of this application proposes a control method for a variable-temperature thermal energy storage water heat release system, comprising: acquiring the temperature correction value of the demineralized water at the outlet of the steam-water mixer, the temperature of the demineralized water at the outlet of the heat exchanger, the measured flow rate of the demineralized water in the bypass of the heat exchanger, and the pressure, temperature, and flow rate of the demineralized water at the inlet of the demineralized water; calculating the enthalpy correction value of the demineralized water at the outlet of the steam-water mixer based on the temperature correction value and the pressure of the demineralized water at the inlet, and calculating the demineralized water at the inlet of the demineralized water based on the pressure and temperature of the demineralized water at the inlet of the demineralized water. Enthalpy: By determining the relationship between the demineralized water temperature at the heat exchanger outlet and the saturation temperature of the demineralized water under pressure at the inlet, the enthalpy of the demineralized water or steam at the heat exchanger outlet is calculated. Based on the enthalpy correction value, the enthalpy of the demineralized water, the enthalpy of the demineralized water or steam, and the flow rate of the demineralized water at the inlet, the flow rate correction value of the demineralized water in the heat exchanger bypass is calculated. The deviation between the measured flow rate and the flow rate correction value is used as input for PID calculation to obtain the change in the opening command of the heat exchanger bypass flow control valve. The control valve is adjusted according to the change to achieve system control.

[0010] Optionally, in one embodiment of this application, obtaining the temperature correction value of the demineralized water at the outlet of the soda mixer includes:

[0011] Obtain the measured temperature and preset temperature of the demineralized water at the outlet of the steam-water mixer;

[0012] The deviation between the measured temperature and the preset temperature is used as input for secondary PID calculation to obtain the calculation result. The calculation result is summed with the preset temperature to obtain the temperature correction value of the demineralized water at the outlet of the steam-water mixer.

[0013] Optionally, in one embodiment of this application, the enthalpy correction value of the demineralized water at the outlet of the steam-water mixer is calculated based on the temperature correction value and the demineralized water pressure at the inlet, and the enthalpy value of the demineralized water at the inlet is calculated based on the demineralized water pressure and temperature at the inlet, including:

[0014] Based on the temperature correction value and the inlet demineralized water pressure, the enthalpy correction value of the demineralized water at the outlet of the steam-water mixer is calculated using the water enthalpy calculation formula.

[0015] The enthalpy of the demineralized water at the inlet is calculated using the water enthalpy calculation formula based on the pressure and temperature of the demineralized water at the inlet.

[0016] The formula for calculating the enthalpy of water is as follows:

[0017] h = f1(p, t)

[0018] Where h represents the enthalpy of water, f1 represents the enthalpy function of water, p represents the pressure of water, and t represents the temperature of water.

[0019] Optionally, in one embodiment of this application, the enthalpy of the demineralized water or steam at the heat exchanger outlet is calculated by determining the relationship between the demineralized water temperature at the heat exchanger outlet and the saturation temperature under the demineralized water pressure at the inlet, including:

[0020] The saturation temperature of the steam and water at the inlet demineralized water pressure is obtained based on the inlet demineralized water pressure.

[0021] Determine the relative values ​​of the demineralized water temperature and the steam-water saturation temperature at the heat exchanger outlet.

[0022] If the temperature of the demineralized water at the heat exchanger outlet is greater than the steam-water saturation temperature, the steam enthalpy value is calculated using the steam enthalpy calculation formula to obtain the steam enthalpy value at the heat exchanger outlet.

[0023] If the temperature of the demineralized water at the heat exchanger outlet is lower than the steam-water saturation temperature, the enthalpy of the demineralized water at the heat exchanger outlet is calculated using the water enthalpy calculation formula.

[0024] Optionally, in one embodiment of this application, the enthalpy of the demineralized water at the heat exchanger outlet is calculated using the water enthalpy calculation formula and expressed as follows:

[0025] h3 = f1(p0, t3)

[0026] Where h3 represents the enthalpy of the demineralized water at the heat exchanger outlet, f1 represents the enthalpy function of water, p0 represents the pressure of the demineralized water at the inlet, and t3 represents the temperature of the demineralized water at the heat exchanger outlet.

[0027] The enthalpy of the demineralized water at the heat exchanger outlet, calculated using the steam enthalpy calculation formula, is expressed as follows:

[0028] h3 = f2(p0, t3)

[0029] Where h3 represents the enthalpy of the demineralized water at the heat exchanger outlet, f2 represents the steam enthalpy function, p0 represents the demineralized water pressure at the inlet, and t3 represents the demineralized water temperature at the heat exchanger outlet.

[0030] Optionally, in one embodiment of this application, the formula for calculating the flow correction value of the heat exchanger bypass demineralized water is expressed as follows:

[0031]

[0032] Where q2′ represents the flow correction value of the demineralized water bypass of the heat exchanger, q0 represents the flow rate of the demineralized water at the inlet, h4′ represents the enthalpy correction value, h3 represents the enthalpy value of the demineralized water or steam, and h0 represents the enthalpy value of the demineralized water.

[0033] To achieve the above objectives, a second aspect of this application provides a variable-temperature thermal energy storage water-based heat release system, comprising: a thermal energy storage medium and heat exchanger, a steam-water mixer, and a bypass flow regulating valve, wherein...

[0034] The heat storage medium and heat exchanger are respectively connected to the first branch of the demineralized water inlet and the heat exchanger outlet pipeline, and are used for heat exchange between the demineralized water and the molten salt, absorbing heat for phase change vaporization or heating.

[0035] The steam-water mixer is connected to the second branch of the demineralized water inlet, the heat exchanger outlet pipe, and the steam-water mixer outlet pipe, respectively. It is used to mix and exchange heat between the steam-water medium introduced through the heat exchanger outlet pipe and the demineralized water introduced through the second branch of the demineralized water inlet, and then lead it out through the steam-water mixer outlet pipe.

[0036] The bypass flow regulating valve is installed on the second branch of the demineralized water inlet and is used to regulate the flow rate of demineralized water entering the steam-water mixer.

[0037] Optionally, in one embodiment of this application, the first branch of the demineralized water inlet and the second branch of the demineralized water inlet are connected to the demineralized water inlet pipeline, and the system further includes:

[0038] The first data acquisition module is equipped with a demineralized water inlet pressure measuring point, a demineralized water inlet temperature measuring point, and a demineralized water inlet flow measuring point at the demineralized water inlet pipeline, which are used to collect the pressure, temperature, and flow rate of the demineralized water at the demineralized water inlet.

[0039] The second acquisition module sets up a heat exchanger bypass flow measurement point after the bypass flow regulating valve of the second branch of the demineralized water inlet, which is used to collect the measured flow of demineralized water in the bypass of the heat exchanger.

[0040] The third acquisition module sets up a heat exchanger outlet temperature measuring point at the heat exchanger outlet pipeline to collect the demineralized water temperature at the heat exchanger outlet.

[0041] The fourth data acquisition module sets up a temperature measuring point at the outlet of the steam-water mixer to collect the measured temperature of the demineralized water at the outlet of the steam-water mixer.

[0042] To achieve the above objectives, a third aspect of this application provides a computer device including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the control method for the variable temperature thermal energy storage water heat release system described in the above embodiment.

[0043] To achieve the above objectives, a fourth aspect of this application provides a non-transitory computer-readable storage medium that, when the instructions in the storage medium are executed by a processor, can perform a control method for a variable-temperature thermal energy storage water heat release system.

[0044] The variable-temperature thermal energy storage water heat release system and its control method, computer equipment, and non-transitory computer-readable storage medium of this application embodiment solve the technical problem of unstable system operation caused by the large influence of molten salt temperature changes on the outlet phase state and temperature of the heat exchange medium in existing molten salt-steam-water heat release systems. By setting up a steam-water mixer and a bypass flow regulating valve for the heat exchanger, combined with an efficient cascade PID control strategy, the phase state and temperature of the heat extraction medium during the heat release process are not affected by the molten salt temperature changes. This achieves the basic function of stabilizing the phase state and temperature of the heat exchange medium during the heat release process, minimizes the interference of various internal and external factors, ensures stable output heat energy of the system, and facilitates the stable operation of peripheral systems.

[0045] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0046] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0047] Figure 1 A flowchart of a control method for a variable temperature thermal energy storage water heat release system provided in Embodiment 1 of this application;

[0048] Figure 2 This is a control logic flowchart of the control method for the variable temperature thermal energy storage water heat release system according to an embodiment of this application;

[0049] Figure 3 This is a schematic diagram of the structure of a variable temperature thermal energy storage water heat release system provided in Embodiment 2 of this application;

[0050] Figure 4 This is a simplified structural diagram of the variable temperature thermal energy storage source water heat release system according to an embodiment of this application. Detailed Implementation

[0051] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0052] The following description, with reference to the accompanying drawings, describes a variable-temperature thermal energy storage source water heat release system and its control method according to embodiments of this application.

[0053] Figure 1 This is a flowchart of a control method for a variable temperature thermal energy storage water heat release system provided in Embodiment 1 of this application.

[0054] like Figure 1 As shown, the control method for the variable-temperature thermal energy storage water heat release system includes the following steps:

[0055] Step 101: Obtain the temperature correction value of the demineralized water at the outlet of the steam-water mixer, the temperature of the demineralized water at the outlet of the heat exchanger, the measured flow rate of the demineralized water in the bypass of the heat exchanger, and the pressure, temperature and flow rate of the demineralized water at the inlet of the demineralized water.

[0056] Step 102: Calculate the enthalpy correction value of the demineralized water at the outlet of the steam-water mixer based on the temperature correction value and the demineralized water pressure at the inlet, and calculate the enthalpy value of the demineralized water at the inlet based on the demineralized water pressure and temperature at the inlet.

[0057] Step 103: By determining the relationship between the demineralized water temperature at the heat exchanger outlet and the saturation temperature under the demineralized water pressure at the inlet, the enthalpy of the demineralized water or steam at the heat exchanger outlet is calculated.

[0058] Step 104: Calculate the flow correction value of the demineralized water bypass based on the enthalpy correction value, the enthalpy value of the demineralized water or steam, and the flow rate of the demineralized water at the inlet.

[0059] Step 105: The deviation between the measured flow rate and the flow correction value is used as input for PID calculation to obtain the change in the opening command of the heat exchanger bypass flow control valve. The control valve is adjusted according to the change to achieve system control.

[0060] The control method for the variable temperature heat storage source water heat release system in this application embodiment obtains the temperature correction value of the demineralized water at the outlet of the steam-water mixer, the temperature of the demineralized water at the outlet of the heat exchanger, the measured flow rate of the demineralized water in the bypass of the heat exchanger, and the pressure, temperature, and flow rate of the demineralized water at the inlet of the demineralized water. Based on the temperature correction value and the pressure of the demineralized water at the inlet, the enthalpy correction value of the demineralized water at the outlet of the steam-water mixer is calculated, and based on the pressure and temperature of the demineralized water at the inlet, the enthalpy value of the demineralized water at the inlet is calculated. By determining the relationship between the temperature of the demineralized water at the outlet of the heat exchanger and the saturation temperature under the pressure of the demineralized water at the inlet, the enthalpy value of the demineralized water or steam at the outlet of the heat exchanger is calculated. Based on the enthalpy correction value, the enthalpy value of the demineralized water, the enthalpy value of the demineralized water or steam, and the flow rate of the demineralized water at the inlet, the flow rate correction value of the demineralized water in the bypass of the heat exchanger is calculated. The deviation between the measured flow rate and the flow rate correction value is used as input for PID calculation to obtain the change in the opening command of the bypass flow control valve. The control valve is adjusted according to the change to achieve system control. Therefore, this method can solve the technical problem of unstable operation in existing molten salt-steam-water storage heat release systems due to the significant influence of molten salt temperature changes on the outlet phase and temperature of the heat exchange medium. By setting up a steam-water mixer and a bypass flow regulating valve for the heat exchanger, combined with an efficient cascade PID control strategy, the phase and temperature of the heat extraction medium during the heat release process are not affected by changes in the molten salt temperature. This achieves the basic function of stabilizing the phase and temperature of the heat exchange medium during the heat release process, minimizing interference from various internal and external factors, ensuring stable output heat energy, and facilitating the stable operation of peripheral systems.

[0061] This application employs cascaded PID control. The secondary PID operator calculates the corrected value for the mixer outlet temperature, while the primary PID operator outputs the opening of the heat exchanger bypass flow control valve. This mitigates the adverse effects of system inertia to a certain extent and provides a rapid response to any deviation from the final target value. Furthermore, by adjusting the bypass demineralized water flow through the bypass flow control valve, this application enables the steam-water mixer to automatically match the system operating conditions when the temperature of the heat storage medium changes, maintaining a constant outlet demineralized water temperature and ensuring stable system heat output load.

[0062] When the system outlet demineralized water temperature setpoint is changed, any changes in system parameters can be mitigated by autonomously adjusting the temperature and phase of the outlet demineralized water to stabilize the system's operating conditions. Furthermore, if the parameters of the demineralized water introduced into the system change, the control system can autonomously correct and adjust relevant valve positions to stabilize the outlet demineralized water temperature. When external systems require changes to the system's heat release load (i.e., changing the outlet demineralized water temperature), only the temperature setpoint needs to be modified. This allows for efficient and autonomous adjustment, quickly changing the outlet demineralized water temperature to meet the needs of external systems. While the heat storage medium in this application is molten salt, the related system and control method are applicable to all heat storage media with similar physical properties to molten salt. Regardless of whether the heat storage medium is temperature-stable or unstable during operation, this application can achieve stable external heat energy output. In summary, the system and control method of this application are practically feasible in industrial production. Their design, installation, use, and maintenance are simple, the technical requirements are appropriate, and they possess the prospects and conditions for large-scale application.

[0063] Further, in this embodiment of the application, obtaining the temperature correction value of the demineralized water at the outlet of the soda mixer includes:

[0064] Obtain the measured temperature and preset temperature of the demineralized water at the outlet of the steam-water mixer;

[0065] The deviation between the measured temperature and the preset temperature is used as input for secondary PID calculation to obtain the calculation result. The calculation result is summed with the preset temperature to obtain the temperature correction value of the demineralized water at the outlet of the steam-water mixer.

[0066] Further, in this embodiment, the enthalpy correction value of the demineralized water at the outlet of the steam-water mixer is calculated based on the temperature correction value and the demineralized water pressure at the inlet, and the enthalpy value of the demineralized water at the inlet is calculated based on the demineralized water pressure and temperature at the inlet, including:

[0067] Based on the temperature correction value and the inlet demineralized water pressure, the enthalpy correction value of the demineralized water at the outlet of the steam-water mixer is calculated using the water enthalpy calculation formula.

[0068] The enthalpy of the demineralized water at the inlet is calculated using the water enthalpy calculation formula based on the pressure and temperature of the demineralized water at the inlet.

[0069] The formula for calculating the enthalpy of water is as follows:

[0070] h = f1(p, t)

[0071] Where h represents the enthalpy of water, f1 represents the enthalpy function of water, p represents the pressure of water, and t represents the temperature of water.

[0072] Further, in this embodiment of the application, the enthalpy of the demineralized water or steam at the heat exchanger outlet is calculated by determining the relationship between the demineralized water temperature at the heat exchanger outlet and the saturation temperature under the demineralized water pressure at the inlet, including:

[0073] The saturation temperature of the steam and water at the inlet demineralized water pressure is obtained based on the inlet demineralized water pressure.

[0074] Determine the relative values ​​of the demineralized water temperature and the steam-water saturation temperature at the heat exchanger outlet.

[0075] If the temperature of the demineralized water at the heat exchanger outlet is greater than the steam-water saturation temperature, the steam enthalpy value is calculated using the steam enthalpy calculation formula to obtain the steam enthalpy value at the heat exchanger outlet.

[0076] If the temperature of the demineralized water at the heat exchanger outlet is lower than the steam-water saturation temperature, the enthalpy of the demineralized water at the heat exchanger outlet is calculated using the water enthalpy calculation formula.

[0077] Furthermore, in this embodiment of the application, the enthalpy of the demineralized water at the heat exchanger outlet is calculated using the water enthalpy calculation formula and expressed as follows:

[0078] h3 = f1(p0, t3)

[0079] Where h3 represents the enthalpy of the demineralized water at the heat exchanger outlet, f1 represents the enthalpy function of water, p0 represents the pressure of the demineralized water at the inlet, and t3 represents the temperature of the demineralized water at the heat exchanger outlet.

[0080] The enthalpy of the demineralized water at the heat exchanger outlet, calculated using the steam enthalpy calculation formula, is expressed as follows:

[0081] h3 = f2(p0, t3)

[0082] Where h3 represents the enthalpy of the demineralized water at the heat exchanger outlet, f2 represents the steam enthalpy function, p0 represents the demineralized water pressure at the inlet, and t3 represents the demineralized water temperature at the heat exchanger outlet.

[0083] Furthermore, in the embodiments of this application, the calculation formula for the flow correction value of the heat exchanger bypass demineralized water is expressed as follows:

[0084]

[0085] Where q2′ represents the flow correction value of the demineralized water bypass of the heat exchanger, q0 represents the flow rate of the demineralized water at the inlet, h4′ represents the enthalpy correction value, h3 represents the enthalpy value of the demineralized water or steam, and h0 represents the enthalpy value of the demineralized water.

[0086] The control method for the variable-temperature thermal energy storage water heat release system in this application requires real-time acquisition of data on demineralized water inlet pressure, temperature, and flow rate, heat exchanger bypass flow rate, heat exchanger outlet temperature, and mixer outlet temperature. Automatic adjustment is achieved through a cascade PID control strategy. The specific control steps are as follows:

[0087] 1) Based on the measured temperature t4 of the demineralized water at the mixer outlet and the set temperature t 4sp The correction value t4′ of the demineralized water temperature at the mixer outlet is obtained through PID calculation.

[0088] The specific control process for this step is as follows:

[0089] 1a) The measured temperature t4 of the demineralized water at the mixer outlet and the set temperature t 4sp The deviation is used as the input to the sub-PID operation to calculate the output;

[0090] 1b) Set the temperature t of the demineralized water at the mixer outlet. 4sp The result is summed with the output of the PID calculation obtained in step 1a), and the sum is used as the correction value t4′ for the demineralized water temperature at the mixer outlet.

[0091] 2) Based on the temperature correction value t4′ of the demineralized water at the mixer outlet and the steam-water side pressure p0 of the system, the enthalpy correction value h4′ of the demineralized water at the mixer outlet is obtained using the water enthalpy calculation formula f1.

[0092] The medium that outputs heat energy in the system, i.e., the pressure on the steam-water side, remains consistent with the inlet pressure of the demineralized water, which is p0. The function h is calculated based on the enthalpy of water. 水 =f1(p 水 , t 水 ), and we can calculate h4′=f1(p0,t4′).

[0093] 3) Determine the temperature of the demineralized water at the heat exchanger outlet, t3, relative to the saturation temperature t under the system steam-water side pressure p0. 0s Based on the relationship, the enthalpy h3 of the water or steam at the heat exchanger outlet is calculated using the water enthalpy calculation formula f1 or the steam enthalpy calculation formula f2.

[0094] The specific control process for this step is as follows:

[0095] 3a) Obtain the steam-water saturation temperature t at the system outlet demineralized water pressure p0. 0s ;

[0096] 3b) Compare the demineralized water temperature t3 at the heat exchanger outlet with the steam-water saturation temperature t 0s Size relationship;

[0097] 3c) When t3 > t 0sThis indicates that a phase change occurs in the medium at the heat exchanger outlet, producing steam, and the function h is calculated based on the enthalpy of the steam. 蒸汽 =f2(p 蒸汽 , t 蒸汽 The enthalpy of the steam at the heat exchanger outlet, h3 = f2(p0, t3), is calculated.

[0098] 3d) When t3 < t 0s This indicates that the medium at the heat exchanger outlet has not undergone a phase change and remains in a liquid state. Therefore, based on the enthalpy function of water, the enthalpy of the demineralized water at the heat exchanger outlet, h3 = f1(p0, t3), can be obtained.

[0099] 4) Based on the system inlet demineralized water temperature t0 and the system steam-water side pressure p0, the system inlet demineralized water enthalpy h0 is obtained using the water enthalpy calculation formula f1.

[0100] The enthalpy of the deionized water at the system inlet can be calculated using the function h0 = f1(p0, t0), where p0 and t0 are real-time monitoring data values ​​of the system.

[0101] 5) Based on the above calculated values ​​h4′, h3, h0, and the measured value q0 of the demineralized water inlet flow rate, the correction value q2′ of the heat exchanger bypass demineralized water flow rate is calculated.

[0102] Based on the calculation results obtained from the above steps, the correction value q2′ for the bypass demineralized water flow rate of the heat exchanger is obtained using the following formula:

[0103]

[0104] Where q0 is the real-time monitoring data value of the system.

[0105] 6) The deviation between the measured flow rate q2 and the corrected flow rate q2′ of the bypass demineralized water is used as the input value for PID calculation. The output of the PID calculation is used as the change in the opening command of the bypass flow control valve of the heat exchanger. The control valve is adjusted to complete the control of the variable temperature heat storage source water heat release system.

[0106] When any operating parameter in the system changes, this cascade PID control strategy can autonomously adjust and converge to achieve stable operation. This application simplifies the variable-temperature thermal energy storage source water heat release system by setting bypass flow regulating valves for the steam-water mixer and heat exchanger. Simultaneously, by combining the deviation between the bypass flow correction value and the real-time value obtained from cascade PID calculations, closed-loop control of the bypass regulating valve is achieved, which to some extent eliminates the adverse effects of large system inertia. Furthermore, it provides a rapid response to any deviation from the final target value, realizing the basic function of stable thermal energy output. This system and control technology ensure that the phase state and temperature of the heat extraction medium are unaffected by changes in the molten salt temperature during the heat release process, minimizing interference from various internal and external factors.

[0107] Figure 2 This is a control logic flowchart of the control method for the variable temperature thermal energy source water heat release system according to an embodiment of this application.

[0108] like Figure 2 As shown, based on the high-temperature water temperature t4 at the mixer outlet and the high-temperature water temperature setpoint t 4sp The corrected value t4′ of the demineralized water temperature at the mixer outlet is obtained through PID calculation; based on the corrected value t4′ of the demineralized water temperature at the mixer outlet and the demineralized water inlet pressure p0, the corrected value h4′ of the enthalpy of the demineralized water at the mixer outlet is obtained using the water enthalpy calculation formula f1; the saturation temperature t3 at the heat exchanger outlet and the demineralized water inlet pressure p0 are compared. 0s Based on the relationship, the enthalpy h3 of the heat exchanger outlet water or steam is calculated using the water enthalpy calculation formula f1 or the steam enthalpy calculation formula f2. According to the demineralized water inlet temperature t0 and the demineralized water inlet pressure p0, the system inlet demineralized water enthalpy h0 is obtained using the water enthalpy calculation formula f1. Based on the above calculated values ​​h4′, h3, h0, and the demineralized water inlet flow rate q0, the heat exchanger bypass demineralized water flow correction value q2′ is calculated. The deviation between the flow rate q2 after the bypass regulating valve and the correction flow rate q2′ is used as the input value for PID calculation. The output of the PID calculation is used as the change in the opening command of the heat exchanger bypass flow regulating valve to adjust the regulating valve, thereby completing the control of the variable temperature heat storage source water heat release system.

[0109] Figure 3 This is a schematic diagram of a variable temperature heat storage source water heat release system provided in Embodiment 2 of this application.

[0110] like Figure 3 As shown, the variable temperature heat storage source water-based heat release system includes: a heat storage medium and heat exchanger, a steam-water mixer, and a bypass flow regulating valve, wherein...

[0111] The heat storage medium and heat exchanger 1 are respectively connected to the first branch of the demineralized water inlet and the heat exchanger outlet pipeline, and are used for heat exchange between the demineralized water and the molten salt, absorbing heat for phase change vaporization or heating.

[0112] The steam-water mixer 2 is connected to the second branch of the demineralized water inlet, the heat exchanger outlet pipe and the steam-water mixer outlet pipe respectively. It is used to mix and exchange heat between the steam-water medium introduced through the heat exchanger outlet pipe and the demineralized water introduced through the second branch of the demineralized water inlet, and then lead it out through the steam-water mixer outlet pipe.

[0113] Bypass flow regulating valve 3 is installed on the second branch of the demineralized water inlet and is used to regulate the flow rate of demineralized water entering the steam-water mixer.

[0114] The variable-temperature thermal energy storage water-based heat release system of this application includes: a thermal energy storage medium and a heat exchanger, a steam-water mixer, and a bypass flow regulating valve. The thermal energy storage medium and the heat exchanger are connected to the first branch of the demineralized water inlet and the heat exchanger outlet pipe, respectively, for heat exchange between the demineralized water and molten salt, absorbing heat for phase change vaporization or temperature increase. The steam-water mixer is connected to the second branch of the demineralized water inlet, the heat exchanger outlet pipe, and the steam-water mixer outlet pipe, respectively, for mixing and heat exchange between the steam-water medium introduced through the heat exchanger outlet pipe and the demineralized water introduced through the second branch of the demineralized water inlet, and then leading out through the steam-water mixer outlet pipe. The bypass flow regulating valve is installed on the second branch of the demineralized water inlet and is used to regulate the flow rate of the demineralized water entering the steam-water mixer. Therefore, this method can solve the technical problem of unstable operation in existing molten salt-steam-water storage heat release systems due to the significant influence of molten salt temperature changes on the outlet phase and temperature of the heat exchange medium. By setting up a steam-water mixer and a bypass flow regulating valve for the heat exchanger, combined with an efficient cascade PID control strategy, the phase and temperature of the heat extraction medium during the heat release process are not affected by changes in the molten salt temperature. This achieves the basic function of stabilizing the phase and temperature of the heat exchange medium during the heat release process, minimizing interference from various internal and external factors, ensuring stable output heat energy, and facilitating the stable operation of peripheral systems.

[0115] The variable-temperature thermal energy storage water-based heat release system of this application can maintain a stable outlet water temperature through autonomous adjustment even when the temperature of the thermal energy storage medium is constantly changing. Furthermore, it is more user-friendly than external systems, better adaptable to various internal and external influencing factors, and maximizes the stability of the system's operating state. The variable-temperature thermal energy storage water-based heat release system of this application has a reasonable design and simple operation control, enriching the application scenarios of molten salt thermal energy storage technology and expanding its application prospects.

[0116] The variable-temperature thermal energy storage water-based heat release system of this application includes: a thermal energy storage medium and a heat exchanger, a steam-water mixer, a bypass flow regulating valve, and necessary connecting pipelines. Simultaneously, this application mainly includes measuring points for demineralized water inlet pressure, demineralized water inlet temperature, demineralized water inlet flow rate, heat exchanger bypass flow rate, heat exchanger outlet temperature, and mixer outlet temperature to conduct real-time monitoring of the system.

[0117] This application introduces a variable-temperature thermal energy storage source water-based heat release system where the demineralized water is divided into two paths. One path enters the molten salt thermal energy storage heat exchanger to absorb heat and increase its temperature; the other path is a bypass path, which, after passing through a flow regulating valve, mixes with the outlet medium of the molten salt heat exchanger in a steam-water mixer. The outlet of the steam-water mixer is the demineralized water that has absorbed heat and increased its temperature, serving as the medium through which the system releases heat. When the temperature of the molten salt in the molten salt thermal energy storage heat exchanger is high, the demineralized water entering the heat exchanger absorbs heat and vaporizes. At this time, the flow rate of the demineralized water in the bypass regulating valve is increased, allowing the steam and bypass demineralized water to exchange heat and mix in the mixer, ensuring a stable outlet temperature for the high-temperature demineralized water, which remains in the liquid phase. When the temperature of the molten salt in the molten salt thermal energy storage heat exchanger is low, the demineralized water entering the heat exchanger absorbs heat and increases its temperature, but does not vaporize. At this time, the flow rate of the demineralized water in the bypass regulating valve is decreased, allowing the high-temperature water and bypass demineralized water to exchange heat and mix in the mixer, similarly maintaining a stable outlet temperature for the demineralized water. Under any operating condition, by adjusting the flow rate of the bypass regulating valve, the operating conditions in the steam-water mixer can be changed, maintaining a stable system outlet water temperature without phase change. Therefore, the water heat release process of the variable temperature heat storage source water heat release system of this application is not affected by changes in molten salt temperature.

[0118] Furthermore, in this embodiment, the first branch of the demineralized water inlet and the second branch of the demineralized water inlet are connected to the demineralized water inlet pipeline, and the system further includes:

[0119] The first data acquisition module is equipped with a demineralized water inlet pressure measuring point, a demineralized water inlet temperature measuring point, and a demineralized water inlet flow measuring point at the demineralized water inlet pipeline, which are used to collect the pressure, temperature, and flow rate of the demineralized water at the demineralized water inlet.

[0120] The second acquisition module sets up a heat exchanger bypass flow measurement point after the bypass flow regulating valve of the second branch of the demineralized water inlet, which is used to collect the measured flow of demineralized water in the bypass of the heat exchanger.

[0121] The third acquisition module sets up a heat exchanger outlet temperature measuring point at the heat exchanger outlet pipeline to collect the demineralized water temperature at the heat exchanger outlet.

[0122] The fourth data acquisition module sets up a temperature measuring point at the outlet of the steam-water mixer to collect the measured temperature of the demineralized water at the outlet of the steam-water mixer.

[0123] Figure 4 This is a simplified structural diagram of the variable temperature thermal energy storage source water heat release system according to an embodiment of this application.

[0124] like Figure 4 As shown, the variable temperature heat storage source water heat release system includes: heat storage medium and heat exchanger (1), steam-water mixer (2), bypass flow regulating valve (3) and other main equipment, and is connected by system pipelines such as demineralized water inlet pipe (4), heat exchanger outlet pipe (5), and mixer outlet pipe (6). The system is also equipped with necessary operating status monitoring sensors such as demineralized water inlet pressure measuring point (7), demineralized water inlet temperature measuring point (8), demineralized water inlet flow measuring point (9), heat exchanger bypass flow measuring point (10), heat exchanger outlet temperature measuring point (11), and mixer outlet temperature measuring point (12).

[0125] In this application, the heat-absorbing medium is introduced into the system through the demineralized water inlet pipe (4) and then split into the heat storage medium and heat exchanger (1) branch and the bypass flow regulating valve (3) branch. The demineralized water exchanges heat with the molten salt in the heat storage medium and heat exchanger (1), absorbing heat and undergoing phase change vaporization or temperature rise. Another branch of demineralized water enters the steam-water mixer (2) after being adjusted by the bypass flow regulating valve (3). The steam-water medium after absorbing heat enters the steam-water mixer (2) through the heat exchanger outlet pipe (5) and mixes and exchanges heat with the demineralized water introduced through the bypass, and then exits the system through the mixer outlet pipe (6).

[0126] This application installs a demineralized water inlet pressure measuring point (7), a demineralized water inlet temperature measuring point (8), and a demineralized water inlet flow measuring point (9) at the demineralized water inlet pipeline (4) to obtain real-time data of brine inlet pressure p0, temperature t0, and flow rate q0, respectively. A heat exchanger bypass flow measuring point (10) is installed after the bypass flow regulating valve (3) to obtain the heat exchanger bypass demineralized water flow rate q2. A heat exchanger outlet temperature measuring point (11) is installed at the heat exchanger outlet pipeline (5) to obtain the heat exchanger outlet medium temperature t3. A mixer outlet temperature measuring point (12) is installed at the mixer outlet pipeline (6) to obtain the system outlet demineralized water temperature t4.

[0127] When the system is running, if the temperature of the molten salt in the heat storage medium and heat exchanger (1) is high, the temperature t3 of the medium in the outlet pipe (5) of the heat exchanger will be high, and phase change vaporization may even occur. At this time, the flow rate q2 of the demineralized water entering the steam-water mixer (2) is increased by the bypass flow regulating valve (3) so that the medium at the system outlet is in the liquid phase and the temperature t4 remains stable. As the heat release process of the system proceeds, the temperature of the molten salt in the heat storage medium and heat exchanger (1) gradually decreases. At this time, it is necessary to continuously reduce the flow rate q2 of the demineralized water entering the steam-water mixer (2) by the bypass flow regulating valve (3) and maintain the temperature t4 stable.

[0128] To implement the above embodiments, this application also proposes a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the control method for the variable temperature thermal storage source water heat release system described in the above embodiments.

[0129] To implement the above embodiments, this application also proposes a non-transitory computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the control method of the variable temperature thermal energy storage source water heat release system of the above embodiments.

[0130] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0131] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0132] Any process or method description in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more executable instructions for implementing custom logic functions or processes, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of this application pertain.

[0133] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0134] It should be understood that various parts of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented using software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0135] Those skilled in the art will understand that all or part of the steps of the methods in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.

[0136] Furthermore, the functional units in the various embodiments of this application can be integrated into a processing module, or each unit can exist physically separately, or two or more units can be integrated into a module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0137] The storage medium mentioned above can be a read-only memory, a disk, or an optical disk, etc. Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of this application.

Claims

1. A control method for a variable-temperature thermal energy storage water-based heat release system, characterized in that, Includes the following steps: Obtain the measured temperature and preset temperature of the demineralized water at the outlet of the steam-water mixer; The deviation between the measured temperature and the preset temperature is used as input to perform secondary PID calculation to obtain the calculation result. The calculation result is summed with the preset temperature to obtain the temperature correction value of the demineralized water at the outlet of the steam-water mixer. Obtain the demineralized water temperature at the heat exchanger outlet, the measured flow rate of the demineralized water in the heat exchanger bypass, and the pressure, temperature, and flow rate of the demineralized water at the demineralized water inlet; Based on the temperature correction value and the demineralized water pressure at the demineralized water inlet, the enthalpy correction value of the demineralized water at the outlet of the steam-water mixer is calculated using the water enthalpy calculation formula. Based on the demineralized water pressure and temperature at the demineralized water inlet, the enthalpy of the demineralized water at the inlet is calculated using the water enthalpy calculation formula, which is expressed as follows: in, This represents the enthalpy of water. The function representing the enthalpy of water, Indicates water pressure, Indicates the temperature of the water; The enthalpy of the demineralized water or steam at the heat exchanger outlet is calculated by determining the relationship between the demineralized water temperature at the heat exchanger outlet and the saturation temperature of the demineralized water under the pressure at the demineralized water inlet. Based on the enthalpy correction value, the enthalpy of the demineralized water at the desalination salt inlet, the enthalpy of the demineralized water or steam at the heat exchanger outlet, and the flow rate of the demineralized water at the desalination salt inlet, the flow rate correction value of the heat exchanger bypass demineralized water is calculated. The formula for calculating the flow rate correction value of the heat exchanger bypass demineralized water is as follows: in, This indicates the flow correction value for the bypass demineralized water in the heat exchanger. This indicates the flow rate of demineralized water at the desalination inlet. This indicates the enthalpy correction value. This indicates the enthalpy of the demineralized water or steam at the heat exchanger outlet. This indicates the enthalpy value of the dehydrated salt inlet; The deviation between the measured flow rate and the flow correction value is used as input for PID calculation to obtain the change in the opening command of the heat exchanger bypass flow regulating valve. The regulating valve is adjusted according to the change to achieve control of the system.

2. The method as described in claim 1, characterized in that, The step of calculating the enthalpy of the demineralized water or steam at the heat exchanger outlet by determining the relationship between the demineralized water temperature at the heat exchanger outlet and the saturation temperature of the demineralized water under pressure at the desalination salt inlet includes: The steam-water saturation temperature at the demineralized water pressure at the demineralized water inlet is obtained based on the demineralized water pressure at the demineralized water inlet. Determine the relative values ​​of the demineralized water temperature at the heat exchanger outlet and the steam-water saturation temperature. If the temperature of the demineralized water at the outlet of the heat exchanger is greater than the steam-water saturation temperature, the enthalpy of the steam at the outlet of the heat exchanger is calculated using the steam enthalpy calculation formula. If the temperature of the demineralized water at the outlet of the heat exchanger is lower than the steam-water saturation temperature, the enthalpy of the demineralized water at the outlet of the heat exchanger is calculated using the water enthalpy calculation formula.

3. The method as described in claim 2, characterized in that, The enthalpy of the demineralized water at the heat exchanger outlet, calculated using the water enthalpy calculation formula, is expressed as follows: in, This indicates the enthalpy of the demineralized water at the heat exchanger outlet. The function representing the enthalpy of water, This indicates the pressure of the demineralized water at the desalination inlet. This indicates the temperature of the demineralized water at the heat exchanger outlet. The enthalpy of the demineralized water at the heat exchanger outlet, calculated using the steam enthalpy calculation formula, is expressed as follows: in, This indicates the enthalpy of the demineralized water at the heat exchanger outlet. Represents the enthalpy function of vapor. This indicates the pressure of the demineralized water at the desalination inlet. This indicates the temperature of the demineralized water at the heat exchanger outlet.

4. A variable-temperature thermal energy storage water-based heat release system, characterized in that, The system is used to implement the control method for the variable temperature thermal energy storage water heat release system as described in claim 1, wherein the system includes: a thermal energy storage medium and a heat exchanger, a steam-water mixer, and a bypass flow regulating valve, wherein... The heat storage medium and heat exchanger are respectively connected to the first branch of the demineralized water inlet and the heat exchanger outlet pipeline, and are used for heat exchange between the demineralized water and the molten salt, absorbing heat for phase change vaporization or heating. The steam-water mixer is connected to the second branch of the demineralized water inlet, the outlet pipe of the heat exchanger, and the outlet pipe of the steam-water mixer, respectively. It is used to mix and exchange heat between the steam-water medium introduced through the outlet pipe of the heat exchanger and the demineralized water introduced through the second branch of the demineralized water inlet, and then lead it out through the outlet pipe of the steam-water mixer. The bypass flow regulating valve is installed on the second branch of the demineralized water inlet and is used to regulate the flow rate of demineralized water entering the steam-water mixer; The first branch of the demineralized water inlet and the second branch of the demineralized water inlet are connected to the demineralized water inlet pipeline. The system also includes: The first data acquisition module is equipped with a demineralized water inlet pressure measuring point, a demineralized water inlet temperature measuring point, and a demineralized water inlet flow measuring point at the demineralized water inlet pipeline, for collecting the pressure, temperature, and flow rate of the demineralized water at the demineralized water inlet. The second acquisition module has a heat exchanger bypass flow measurement point set after the bypass flow regulating valve of the second branch of the demineralized water inlet, which is used to collect the measured flow of the demineralized water in the bypass of the heat exchanger. The third acquisition module is equipped with a heat exchanger outlet temperature measuring point at the heat exchanger outlet pipeline to collect the demineralized water temperature at the heat exchanger outlet. The fourth data acquisition module is equipped with a temperature measuring point at the outlet of the steam-water mixer to collect the measured temperature of the demineralized water at the outlet of the steam-water mixer.

5. A computer device, characterized in that, It includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, it implements the method as described in any one of claims 1-3.

6. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the method as described in any one of claims 1-3.

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