Sensible heat energy storage system for hot water-steam cogeneration based on alternate cooling and heating control strategy

Abstract

The invention discloses a sensible heat energy storage system and method for hot water-steam co-production based on a cooling and heating alternating control strategy, and belongs to the technical field of sensible heat energy storage. The system comprises a multi-stage water storage module composed of a cold water tank, a medium-temperature water tank and a hot water tank, a plurality of energy storage devices filled with solid-phase heat storage materials, a header, a power valve / three-way valve assembly and a steam pocket. The control module dynamically switches the flow direction of the working medium according to the energy storage device outlet temperature threshold value and the water tank liquid level threshold value. During heat charging, high-temperature steam is stored in the corresponding water tanks according to outlet temperatures in a graded mode, and the modules with the too low temperature are preheated through the medium-temperature water tanks and the high-temperature water tanks; during heat release, working media in the cold water tank and the hot water tank are alternately switched to enter the two or more energy accumulators, circulating heating is triggered in combination with the liquid level, and stable co-production of hot water and steam is achieved. Through multi-water-tank hierarchical storage and alternate cooling and heating control, two-phase flow instability is effectively inhibited, the service life of equipment is prolonged, and the stability of output parameters is improved.

Description

Technical Field

[0001] The present invention relates to a sensible heat energy storage system, and in particular to a sensible heat energy storage system for hot water-steam cogeneration based on a cold-hot alternating control strategy. Background Art

[0002] In the prior art, the sensible heat energy storage system based on high temperature resistant solid phase materials (such as gravel, graphite, steel) and shell-and-tube packed bed energy storage devices transfers the heat of the heat-carrying fluid to the energy storage material for storage through heat exchange tubes during charging, and transfers the heat in the opposite direction during heat release for reuse.

[0003] Such systems are widely used in power generation, industrial preheating and other fields, but they have significant defects: Due to the huge difference in density, compressibility and viscosity between water and water vapor, two-phase flow instability is prone to occur in the heat exchange tube, which is specifically manifested as violent oscillations in mass flow, pressure and tube wall temperature, resulting in shortened equipment life, fluctuations in outlet parameters, and unstable charging and discharging power. Although existing technologies attempt to adjust by detecting the instability boundary of two-phase flow, they are unable to fundamentally solve this problem due to the influence of dynamic changes in heat flux caused by changes in the temperature of the energy storage material. Summary of the invention

[0004] The purpose of the present invention is to address the above-mentioned problems existing in the prior art and to provide a sensible heat energy storage system for hot water-steam cogeneration based on a cold-hot alternating control strategy. Through the coordinated control of a multi-tank structure (cold water tank, medium-temperature water tank, hot water tank) and a manifold-valve assembly, combined with a dynamic path switching strategy triggered by temperature thresholds (such as 70°C, 120°C, 170°C) and liquid level thresholds (75%, 50% of full scale), the instability of two-phase flow is suppressed to achieve stable cogeneration of hot water and steam, thereby solving the problem that the existing sensible heat energy storage system is difficult to achieve stable output and cannot simultaneously and efficiently cogenerate hot water and steam due to the instability of the water-vapor two-phase flow, which causes the working fluid parameters to oscillate.

[0005] In order to achieve the above application purpose, the present invention adopts the following technical solution: A sensible heat storage system for hot water-steam cogeneration based on a cold-hot alternating control strategy comprises: The stratified water supply module includes a cold water tank, a medium-temperature water tank and a hot water tank, which are used to store working fluids at different temperatures in stages. When releasing heat, cold water and hot water alternately enter the high-temperature energy storage device to preheat the working fluid and produce steam. A plurality of energy storage devices connected in parallel with the stratified water supply module, each of which is filled with a solid-phase sensible heat storage material for exchanging heat with a heat-carrying fluid through a heat exchange tube; Multiple headers are connected to the stratified water supply module and the accumulator, and the accumulator and the steam drum through pipelines, and are used for the distribution and collection of working fluids, and for the superposition of accumulators; Multiple power valves and multiple three-way valves are arranged on the pipelines between the header and each water tank and energy storage device to dynamically adjust the flow direction of the working fluid; The steam drum is connected to the hot water tank and the header corresponding to each accumulator, and is used for steam-water separation and steam output; The control module triggers the opening and closing of the power valve and the three-way valve and the switching path according to the outlet working medium temperature threshold of the energy storage device and the liquid level threshold of the water tank, so as to realize the hot and cold alternating control in the charging stage and the heat release stage; the configuration is: In the charging stage, the working fluid is distributed to the cold water tank, the medium temperature water tank or the hot water tank according to the working fluid temperature at the outlet of the energy storage device; During the heat release stage, the working fluids from the cold water tank and the hot water tank are switched alternately to enter the energy storage device, and the flow direction of the working fluid is dynamically adjusted according to the temperature and liquid level parameters.

[0006] Further, the charging stage includes: When the working fluid temperature at the outlet of the energy storage device is lower than the first temperature threshold, the working fluid flows to the cold water tank; When the working fluid temperature at the outlet of the energy storage device is between the first temperature threshold and the second temperature threshold, the working fluid flows to the medium temperature water tank; When the working medium temperature at the outlet of the energy storage device is between the second temperature threshold and the third temperature threshold, the working medium flows to the hot water tank; When there is an energy storage device whose temperature is lower than the second temperature threshold or the third temperature threshold and which is not heated by high-temperature steam, the energy storage device is heated by the working fluid in the medium-temperature water tank or the high-temperature water tank (the module here refers to the use of the medium-temperature or hot water tank to preheat the module whose temperature is too low and is not heated by steam); The exothermic phase includes: The circulation of the working fluid from the water tank to the energy storage device is triggered according to the liquid level threshold, and the working fluid is redistributed to the medium-temperature water tank, the hot water tank or the external steam drum based on the outlet working fluid temperature threshold to jointly produce hot water and steam.

[0007] Further, the first temperature threshold is 70°C, the second temperature threshold is 120°C, and the third temperature threshold is 170°C.

[0008] Furthermore, the liquid level threshold of the cold water tank is 75% of the full scale, and the liquid level thresholds of the medium-temperature water tank and the hot water tank are both 50% of the full scale. When the liquid level exceeds the liquid level threshold, the corresponding power valve is triggered to open to discharge the working fluid to the external circulation pipeline.

[0009] Furthermore, the energy storage device heat release end temperature threshold is 150° C. When the average temperature is lower than the threshold, the energy storage device is switched to the next energy storage device to continue heat release.

[0010] Furthermore, the energy storage device filling material is a solid-phase sensible heat storage material, and the heat exchange tube is a copper tube or a stainless steel tube.

[0011] Furthermore, the operating pressure of the sensible heat energy storage system is 0.3MPa corresponding to heat release and 1MPa corresponding to heat charging, and the working fluid circulation path is monitored and adjusted in real time through a pressure sensor.

[0012] In order to achieve the above application purpose, the present invention also adopts the following technical solutions: A control method for a hot water-steam cogeneration sensible heat energy storage system based on a hot and cold alternating control strategy comprises the following steps: Control steps of heating stage: (a) High-temperature steam is introduced into the energy storage device to detect the outlet working fluid temperature of the energy storage device in real time; (b) According to the comparison result between the outlet working fluid temperature and the preset temperature threshold, the three-way valve path is switched to allocate the working fluid flow direction: When the outlet working fluid temperature is lower than a first temperature threshold, directing the working fluid to a cold water tank; When the outlet working fluid temperature is between the first temperature threshold and the second temperature threshold, directing the working fluid to the medium temperature water tank; When the outlet working fluid temperature is between the second temperature threshold and the third temperature threshold, directing the working fluid to the hot water tank; (c) When the liquid level in the hot water tank reaches 75% of the full scale, open the power valve corresponding to the hot water tank to discharge the working fluid into the external circulation pipeline; Exothermic stage control steps: (d) Pumping normal temperature water from the external circulation pipeline into the cold water tank, maintaining the liquid level of the cold water tank at 75% of the full scale, pumping normal temperature water from the cold water tank into the energy storage device, and monitoring the liquid levels of the medium temperature water tank and the hot water tank in real time; (e) When the liquid level of the medium temperature water tank exceeds 50% of the full scale, the power valve corresponding to the medium temperature water tank is opened to introduce the working fluid into the external circulation pipeline for heat release; (f) When the liquid level in the hot water tank exceeds 50% of the full scale, the power valve corresponding to the hot water tank is opened to transport the working fluid to the energy storage device; (g) Dynamically adjust the working fluid distribution based on the comparison between the working fluid temperature at the outlet of the energy storage device and the steam generation threshold: When the liquid level in the hot water tank continuously exceeds 50% of the full scale during the heat release stage, the three-way valve path is switched alternately at a set time cycle, so that the working medium circulation between two or more energy storage devices and the water supply system is switched between the cold water tank and the hot water tank in an alternating order; When the working fluid in the cold water tank is used to circulate with the heat storage device (high flow), the outlet working fluid is distributed to the medium temperature water tank or the hot water tank according to the module outlet temperature.

[0013] When the working fluid in the hot water tank and the heat storage are circulated (low flow), if the outlet working fluid temperature reaches or exceeds the steam generation threshold, the working fluid is transported to the steam drum for steam-water separation, the separated steam is output, and the hot water is returned to the hot water tank; If the outlet working fluid temperature is lower than the steam generation threshold, the working fluid will be redistributed to the hot water tank for circulation heating.

[0014] Furthermore, in the charging stage, multiple energy storage devices are charged in sequence according to a preset order, and the working fluid with an outlet temperature higher than the temperature threshold is collected into a medium-temperature water tank or a hot water tank, and the medium-temperature and hot water tanks are used to preheat the modules with too low temperatures; in the heat release stage, multiple energy storage devices are connected in parallel through a header and a water supply tank, and the working fluid path is dynamically allocated according to the temperature difference of the working fluid at the outlet of each energy storage device. When the hot water tank and the cold water tank are used to alternately provide circulating working fluid for heat release, the steam drum is used to continuously output steam, and the medium-temperature water tank outputs hot water.

[0015] Further, the first temperature threshold is 70°C, the second temperature threshold is 120°C, the third temperature threshold is 170°C, and the steam generation threshold is 133°C.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. Solve the problem of two-phase flow instability: By lowering the temperature of the heat exchange tube wall of the accumulator during the cold water preheating stage (e.g., from 330°C to below 110°C), the normal heat flux of the tube wall during hot water steam production is reduced. Experiments have shown that the standard deviation of the outlet pressure is reduced by 50%, significantly weakening parameter oscillations to achieve a more stable supply of steam to the outside world.

[0017] 2. Achieve efficient co-production of hot water and steam: The medium-temperature water tank directly provides stable hot water ≤133°C (output when the liquid level is ≥50%), and the steam drum separates high-quality steam (temperature ≥133°C), realizing dual-product output and expanding application scenarios.

[0018] 3. Modular expansion and efficient charging and discharging Energy storage devices can be stacked infinitely and flexibly configured in series / parallel through headers; when charging, they are stored according to temperature levels (such as 70℃→120℃→170℃ thresholds), and when releasing heat, high-temperature energy storage devices are used to produce steam first, thereby improving energy utilization efficiency.

[0019] 4. Extend the service life of equipment: The hot and cold alternating control strategy (such as switching the working fluid path in a 10-minute cycle) avoids local overheating of the energy storage device and weakens the water vapor impact corrosion and pipeline vibration caused by the oscillation of the working fluid pressure and flow parameters in the tube, thereby increasing the service life of the tube. The system cycle life can be increased to more than twice that of the existing technology.

[0020] 4. Parameter adaptive optimization: The charging and discharging thermal pressure (0.3MPa / 1MPa) is linked to the temperature threshold for control, ensuring that the working fluid circulation path matches the thermodynamic properties of the material, significantly improving the charging and discharging energy efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic structural diagram of an embodiment of the present invention; Figure 2 It is a curve diagram of the fluctuation of parameters in the tube when hot water is used to directly release energy in the prior art; Figure 3 It is a curve diagram of the standard deviation of the outlet pressure fluctuation versus time interval of the prior art; Figure 4 is a curve diagram of the fluctuation of the parameters in the tube when the cold and hot energy are released alternately in the embodiment of the present invention; Figure 5 4 is a curve diagram showing the change of the standard deviation of the outlet pressure fluctuation with the time interval according to an embodiment of the present invention.

[0022] In the figure, 1, 24, 26—working medium circulation pumps; 2, 7, 30, 37, 39—inlet and outlet of external working medium circulation pipeline; 3, 10, 11, 12, 13, 14, 15, 16, 17, 18, 31, 32, 33, 34, 35, 36—power valve; 4—Cold water tank (normal temperature water tank); 5—Medium temperature water tank; 6—hot water tank (high temperature water tank); 8, 9, 20, 22, 23, 25—power three-way valve; 19—first energy storage device inlet header; 21—Xth energy storage device inlet header; 27—first energy storage device; 28—Xth energy storage device; 29—the first energy storage device outlet header; 38—steam drum; 40—Xth energy storage device outlet header; 41—Liquid level sensor; 42—Pressure sensor. DETAILED DESCRIPTION

[0023] The following will be combined with the accompanying 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 belong to the scope of protection of the present invention.

[0024] Those skilled in the art should understand that, in the disclosure of the present invention, the orientation or position relationship indicated by terms such as "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientation or position relationship shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the above terms should not be understood as limiting the present invention.

[0025] Example 1 like Figure 1 As shown, the sensible heat storage system for hot water-steam cogeneration based on the cold-hot alternating control strategy includes: 1. Stratified water supply module Cold water tank 4: stores normal temperature water (≤70°C) and is not limited to water, but can be other working fluids. It is connected to the inlet and outlet 2 of the external working fluid circulation pipeline and the energy storage device (27, 28) through the power valve (3, 13, 14), and is also connected to the medium temperature water tank 5 through the pipeline and the power valve 11. The energy storage device (27, 28) here does not refer to two energy storage devices (the same below), but the first energy storage device 27 and the Xth energy storage device 28. The number of energy storage devices can be infinitely stacked.

[0026] The medium temperature water tank 5 stores working fluids at 70°C to 120°C and is connected to the energy storage device (27, 28) and the inlet and outlet 7 of the external working fluid circulation pipeline through the power valves (10, 15, 16). It is also connected to the power three-way valve 8 and is connected to the hot water tank 6 through the power valve 12 and the pipeline.

[0027] Hot water tank 6: stores working fluid at 120°C to 170°C, and is connected to the energy storage device (27, 28) through the power valve (17, 18, 9), and is also connected to the steam drum 38 and the power three-way valve 9 respectively.

[0028] 2. Energy storage module Energy accumulators (27, 28): filled with graphite (or gravel, refractory bricks), with built-in copper tubes (diameter 18 mm, length 1.5 m), stacked through inlet headers (19, 21) and outlet headers (29, 40). The inlet headers (19, 21) and outlet headers (29, 40) here do not refer to two headers respectively, but the first energy accumulator inlet header 19 and the X-th energy accumulator inlet header 21, as well as the first energy accumulator outlet header 29 and the X-th energy accumulator outlet header 40. Each energy accumulator is provided with an inlet header and an outlet header.

[0029] Inlet header and outlet header: distribute the working fluid to each accumulator to achieve modular expansion. For example, the first accumulator inlet header 19 is connected to the cold water tank 4, the medium temperature water tank 5 and the hot water tank 6 through power valves (13, 15, 17). The X-th accumulator inlet header 21 is connected to the cold water tank 4, the medium temperature water tank 5 and the hot water tank 6 through power valves (14, 16, 18). The first accumulator outlet header 29 is connected to the external working fluid circulation pipeline inlet and outlet 30, the steam drum 38 and the power three-way valve 8 through power valves (31, 32, 33). The X-th accumulator outlet header 40 is connected to the external working fluid circulation pipeline inlet and outlet 37, the steam drum 38 and the power three-way valve 9 through power valves (34, 35, 36).

[0030] 3. Valves and steam drums Power valves (3, 10-18, 31-36): control the on / off and flow direction of the working fluid (e.g., power valves 13-18 control the path from the cold water tank to the energy storage device). The number of power valves increases as the number of energy storage devices increases. Power valve 31 is connected to the inlet and outlet 30 of the external working fluid circulation pipeline, and power valve 34 is connected to the inlet and outlet 37 of the external working fluid circulation pipeline.

[0031] Power three-way valve (8, 9, 20, 22, 23, 25): switch the working fluid diversion path (such as power three-way valve 23 and power three-way valve 20 control the working fluid at the outlet of the energy storage device to the cold water tank), Figure 1 In the figure, the power three-way valve 8 is respectively connected to the power valve 33, the medium-temperature water tank 5 and the hot water tank 6, the power three-way valve 8 is respectively connected to the power valve 36, the medium-temperature water tank 5 and the hot water tank 6, the power three-way valve 20 is respectively connected to the first accumulator inlet header 19, the working fluid circulation pump 24 and the power three-way valve 23, the power three-way valve 22 is respectively connected to the X-th accumulator inlet header 21, the working fluid circulation pump 26 and the power three-way valve 25, the power three-way valve 23 is respectively connected to the first accumulator 27, the working fluid circulation pump 24 and the power three-way valve 20, and the power three-way valve 25 is respectively connected to the X-th accumulator 28, the working fluid circulation pump 26 and the power three-way valve 22.

[0032] Steam drum 38: connected to the hot water tank 6 and the accumulator outlet header (29, 40), separates steam (≥133°C) and hot water (≤133°C), and is also connected to the inlet and outlet 39 of the external working medium circulation pipeline to provide steam to the outside.

[0033] Working fluid circulation pump (1, 24, 6): as a power source, it can drive the working fluid to flow, such as the working fluid circulation pump 1 is connected to the cold water tank 4, the two ends of the working fluid circulation pump 24 are respectively connected to the power three-way valve 23 and the power three-way valve 20, and the two ends of the working fluid circulation pump 26 are respectively connected to the power three-way valve 22 and the power three-way valve 25.

[0034] 4. Control module The integrated temperature sensor (monitoring the inlet and outlet of the energy storage device and the water tank temperature), the liquid level sensor 41 (water tank liquid level) and the pressure sensor 42 (system pressure 1MPa charging / 0.3MPa discharging) dynamically adjust the valve state through the logic algorithm. The pressure sensor 42, the temperature sensor 41, the exhaust valve, the drain valve, the safety valve and other instruments are arranged in accordance with the conventional thermal system layout.

[0035] Example 2 Based on the same concept, this embodiment provides a control method for a sensible heat energy storage system based on a hot water-steam cogeneration control strategy based on a cold-hot alternating control strategy. When the heat storage system is in operation, there are two working fluid circulation paths in the charging and discharging processes. The following processes are the circulation paths of the working fluid and valve control cases when the system is charging and discharging heat: 1. When charging, the system operating pressure is 1MPa: 1. High-temperature superheated steam (1MPa 300℃) enters the first energy storage device 27 from the inlet and outlet of the external working medium circulation pipeline 30; 1.1 If the outlet temperature after passing through the first accumulator 27 is lower than 70°C, it will enter the cold water tank 4 through the power three-way valve 23 → power three-way valve 20 → first accumulator inlet manifold 19 → power valve 13; 1.2 If the outlet temperature after passing through the first accumulator 7 is lower than 120°C and higher than 70°C, it will enter the medium temperature water tank 5 through the power three-way valve 23 → power three-way valve 20 → first accumulator inlet manifold 19 → power valve 15; 1.3 If the outlet temperature after passing through the first accumulator 7 is lower than 170°C and higher than 120°C, it will enter the hot water tank 6 through the power three-way valve 23 → power three-way valve 20 → first accumulator inlet manifold 19 → power valve 17; 1.4 If the temperature of the medium temperature water tank 5 is higher than the temperature of the Xth energy accumulator 28, the working fluid enters the inlet and outlet 37 of the external working fluid circulation pipeline from the medium temperature water tank 5 through the power valve 16 → the Xth energy accumulator inlet header 21 → the power three-way valve 22 → the working fluid circulation pump 26 → the power three-way valve 25 → the Xth energy accumulator 28 → the Xth energy accumulator outlet header 40 → the power valve 34; 1.5 If the temperature of the hot water tank 6 is higher than the temperature of the X-th accumulator 28 and the power valve 16 is not opened, the working fluid flows from the hot water tank 6 through the power valve 18 → the X-th accumulator inlet header 21 → the power three-way valve 22 → the working fluid circulation pump 26 → the power three-way valve 25 → into the X-th accumulator 28; if the outlet temperature of the X-th accumulator 28 is higher than 40°C, it flows through the X-th accumulator outlet header 40 → the power valve 36 → the power three-way valve 9 into the medium-temperature water tank; if the outlet temperature of the accumulator is lower than 40°C, it flows through the header-power valve 34 into the inlet and outlet 37 of the external working fluid circulation pipeline; 2. If the outlet temperature after passing through the first energy accumulator 27 is higher than 170°C, the high-temperature steam enters the Xth energy accumulator 28 from the inlet and outlet 37 of the external working medium circulation pipeline of the Xth energy accumulator 28; 2.1 If the outlet temperature after passing through the Xth accumulator 27 is lower than 70°C, it will enter the cold water tank 4 through the power three-way valve 25 → power three-way valve 22 → the Xth accumulator inlet header 21 → power valve 14; 2.2 If the outlet temperature after passing through the Xth accumulator 27 is lower than 120°C and higher than 70°C, it will enter the medium temperature water tank 5 through the power three-way valve 25 → power three-way valve 22 → the Xth accumulator inlet header 21 → power valve 16; 2.3 If the outlet temperature after passing through the first accumulator 27 is lower than 170°C and higher than 120°C, it will enter the hot water tank 6 through the power three-way valve 25 → power three-way valve 22 → first accumulator inlet manifold 21 → power valve 18; 3. If the liquid level in the hot water tank 6 exceeds 75% of the full scale, the power valve 12 opens; if the liquid level in the medium temperature water tank 5 exceeds 75% of the full scale, the power valve 11 opens; if the liquid level in the cold water tank 4 exceeds 75% of the full scale, the power valve 3 opens, and the cold working fluid provides cold water to the external working fluid circulation pipeline through the inlet and outlet 2 of the external working fluid circulation pipeline.

[0036] 4. If the outlet temperature of the high-temperature steam exceeds 170°C after passing through the Xth accumulator 28, the heat charging is completed.

[0037] The number of energy storage devices in this system can be infinite. According to the charging logic provided in this case, the energy storage devices are charged in sequence.

[0038] 2. When releasing heat, the system operating pressure is 0.3MPa: 1. Normal temperature water enters the cold water tank 4 from the power valve 3 at the inlet and outlet 2 of the external working medium circulation pipeline, and the liquid level of the cold water tank 4 is kept at 75% of the full scale. After the liquid level is reached, the cold working medium passes through the power valve 13 → header → No. 20 power three-way valve → working medium circulation pump 24 → power three-way valve 23 and enters the first energy storage device 27; 1.1 If the outlet temperature of the first accumulator 27 is lower than 110°C, the working fluid enters the medium temperature water tank 5 through the first accumulator outlet manifold 29 → power valve 33 → power three-way valve 8; 1.2 If the liquid level of the medium temperature water tank 5 exceeds 50% of the full scale, the power valve 10 opens, and the medium temperature water tank 5 can provide hot water to the external working medium circulation pipeline through the external working medium circulation pipeline inlet and outlet 7; 1.3 If the outlet temperature of the first accumulator 27 is higher than 110°C and lower than 133°C, the working fluid enters the hot water tank 6 through the first accumulator outlet manifold 29 → power valve 33 → power three-way valve 8; 2. If the liquid level in the hot water tank 6 is higher than 50% of the full scale, the working fluid in the cold water tank 4 and the working fluid in the hot water tank 6 are fixedly alternated at a period of 120 seconds. The cold working fluid flows at a high flow rate (2000 kg / h) and the hot working fluid flows at a low flow rate (300 kg / h) periodically and alternately through the power valve 13 and the power valve 17 or the power valves 14 and 18 → the first accumulator inlet manifold 19 or the Xth accumulator inlet manifold 21 → the No. 20 power three-way valve or the No. 22 power three-way valve → the working fluid circulation pump 24 or 26 → the power three-way valve 23 or 25 to enter the first accumulator 27 or the Xth accumulator 28.

[0039] 2.1 If the first energy storage device is in the cold working medium cycle of the cycle, the Xth energy storage device is in the hot working medium (steam production) cycle of the cycle; 2.1.1 If the outlet temperature of the first accumulator 27 is lower than 110°C, the working fluid enters the medium temperature water tank 5 through the first accumulator outlet manifold 29 → power valve 33 → power three-way valve 8; 2.1.2 If the outlet temperature of the first accumulator 27 is higher than or equal to 110°C and lower than 133°C, the working fluid enters the hot water tank 6 through the first accumulator outlet manifold 2 → power valve 33 → power three-way valve 8; 2.1.3 If the outlet temperature of the Xth accumulator 27 is higher than or equal to 133°C, the working fluid passes through the Xth accumulator outlet header 40 → power valve 35 and enters the steam drum 38 for steam-water separation; 2.1.4 The hot water in the drum 38 re-enters the hot water tank 6; 2.1.5 The steam in the steam drum 38 enters the inlet and outlet 39 of the external working medium circulation pipeline to provide steam to the outside world; 2.1.6 If the outlet temperature of the Xth accumulator 27 is lower than 133°C, the working fluid enters the hot water tank through the Xth accumulator outlet manifold 40 → power valve 36 → power three-way valve 9; 3. If the average temperature of the first energy storage device 27 is lower than 150°C, the first energy storage device 27 stops releasing heat, and the Xth energy storage device starts to release heat alternately with other energy storage devices in the system until the number of energy storage devices with a temperature higher than 150°C in the system is less than 2, and the system stops releasing heat.

[0040] When two or more energy storage devices release heat according to the hot-cold alternating control strategy, the number of energy storage devices may be an even number or an odd number.

[0041] This case provides a heat energy release process in accordance with the cold and hot alternating logic in the order of energy storage devices, in which the steam-water separation process in the steam drum is the same as that of common thermal equipment. The core innovation of the present invention is that in the second step, two or more energy storage devices are used to release heat according to the control logic of alternating cold and hot working media, and three water tanks of normal temperature (cold) - medium temperature - high temperature (hot) are set in the system, thereby suppressing the occurrence of two-phase flow instability in the steam production process, and continuously providing steam with more stable export parameters to the outside world; and while generating steam, the medium-temperature water tank 5 is used to provide hot water with a temperature below 133°C to the outside world.

[0042] In order to verify the technical effect of the hot and cold alternating heat release strategy in the present invention, Figure 2 As shown, the size is 0.15*0.15*1.5m, graphite is used as the heat storage material, and a packed bed with a copper tube of 18mm in diameter and 1.5m in length is built horizontally. The heat release starting temperature is 330℃. Under normal working conditions, steam generation and heat release continue after the module is charged. Figure 2 The fluctuation curves of the outlet pressure, mass flow rate and inlet temperature of the packed bed when 95℃ hot water is used as the working fluid for heat release at normal pressure are shown. It can be seen that obvious parameter fluctuations are caused by the instability of the two-phase flow. Figure 3 A curve of the standard deviation of the outlet pressure changing with time is calculated every 60 seconds.

[0043] like Figure 4 As shown in the figure, the fluctuation curve of the parameters in the tube is that the heat is released by using the cold and hot alternating energy release scheme with an alternating cycle of 180s. The time ratio of the cold water preheating and the hot water steam production process is 1:1. Figure 5 The standard deviation of the outlet pressure when the outlet pressure fluctuates in each hot water heat release cycle during hot water steam production. The X-axis is the sequence number of each alternating cycle sorted by time. During the cold water preheating stage, the cold water valve is opened, the water flow increases, the hot water steam production circulation pipeline is switched to the bypass, and the hot water flow increases; when hot water steam is produced, its pipeline is switched to the steam production circulation path, the hot water flow decreases and steam production begins, and the cold water valve is closed.

[0044] By comparison Figure 5 and Figure 3 It can be seen that the standard deviation of the outlet pressure is reduced by 50% in the early stage of energy release when using the hot and cold alternating scheme of the present invention.

[0045] The parts not described in detail in the present invention are prior art, so the present invention does not describe them in detail.

[0046] It is to be understood that the term "one" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element may be one, while in another embodiment, the number of the element may be multiple, and the term "one" should not be understood as a limitation on the quantity.

[0047] Although more professional terms are used in this article, the possibility of using other terms is not excluded. These terms are used only to more conveniently describe and explain the essence of the present invention; interpreting them as any additional restrictions is contrary to the spirit of the present invention.

[0048] The present invention is not limited to the above-mentioned optimal implementation mode. Anyone can derive other various forms of products under the inspiration of the present invention. However, no matter what changes are made in the shape or structure, all technical solutions that are the same or similar to the present invention fall within the protection scope of the present invention.

Claims

1. A hot water-steam cogeneration sensible heat energy storage system based on a hot and cold alternating control strategy, characterized in that: include: The stratified water supply module includes a cold water tank, a medium-temperature water tank and a hot water tank, which are used to store working fluids at different temperatures in stages. When releasing heat, cold water and hot water alternately enter the high-temperature energy storage device to preheat the working fluid and produce steam. A plurality of energy storage devices connected in parallel with the stratified water supply module, each of which is filled with a solid-phase sensible heat storage material for exchanging heat with a heat-carrying fluid through a heat exchange tube; Multiple headers are connected to the stratified water supply module and the accumulator, and the accumulator and the steam drum through pipelines, and are used for the distribution and collection of working fluids, and for the superposition of accumulators; A plurality of power valves and a plurality of three-way valves are arranged on the pipeline between the manifold and each water tank and energy storage device, and are used to dynamically adjust the flow direction of the working medium; The steam drum is connected to the hot water tank and the header corresponding to each accumulator, and is used for steam-water separation and steam output; The control module triggers the opening and closing of the power valve and the three-way valve and the switching path according to the outlet working medium temperature threshold of the energy storage device and the liquid level threshold of the water tank, so as to realize the hot and cold alternating control in the charging stage and the heat release stage; the configuration is as follows: In the charging stage, the working fluid is distributed to the cold water tank, the medium temperature water tank or the hot water tank according to the working fluid temperature at the outlet of the energy storage device; During the heat release stage, the working fluids from the cold water tank and the hot water tank are switched alternately to enter the energy storage device, and the flow direction of the working fluid is dynamically adjusted according to the temperature and liquid level parameters.

2. The sensible heat storage system for hot water-steam cogeneration based on the hot and cold alternating control strategy according to claim 1 is characterized in that: The heating stage includes: When the working fluid temperature at the outlet of the energy storage device is lower than the first temperature threshold, the working fluid flows to the cold water tank; When the working fluid temperature at the outlet of the energy storage device is between the first temperature threshold and the second temperature threshold, the working fluid flows to the medium temperature water tank; When the working medium temperature at the outlet of the energy storage device is between the second temperature threshold and the third temperature threshold, the working medium flows to the hot water tank; When there is an energy storage device whose temperature is lower than the second temperature threshold or the third temperature threshold and which is not charged with high-temperature steam, the energy storage device is charged with the working fluid in the medium-temperature water tank or the high-temperature water tank; The exothermic stage includes: The circulation of the working fluid from the water tank to the energy storage device is triggered according to the liquid level threshold, and the working fluid is redistributed to the medium-temperature water tank, the hot water tank or the external steam drum based on the outlet working fluid temperature threshold to jointly produce hot water and steam.

3. The sensible heat storage system for hot water-steam cogeneration based on the hot and cold alternating control strategy according to claim 2 is characterized in that: The first temperature threshold is 70°C, the second temperature threshold is 120°C, and the third temperature threshold is 170°C.

4. The sensible heat storage system for hot water-steam cogeneration based on the hot and cold alternating control strategy according to claim 2 is characterized in that: The liquid level threshold of the cold water tank is 75% of the full scale, and the liquid level thresholds of the medium-temperature water tank and the hot water tank are both 50% of the full scale. When the liquid level exceeds the liquid level threshold, the corresponding power valve is triggered to open to discharge the working fluid to the external circulation pipeline.

5. The sensible heat storage system for hot water-steam cogeneration based on the hot and cold alternating control strategy according to claim 1 is characterized in that: The energy storage device heat release end temperature threshold is 150° C. When the average temperature is lower than the threshold, the energy storage device is switched to the next energy storage device to continue heat release.

6. The sensible heat storage system for hot water-steam cogeneration based on the hot and cold alternating control strategy according to claim 1 is characterized in that: The energy storage device filling material is a solid-phase sensible heat energy storage material, and the heat exchange tube is a copper tube or a stainless steel tube.

7. The sensible heat storage system for hot water-steam cogeneration based on the hot and cold alternating control strategy according to claim 1 is characterized in that: The operating pressure of the sensible heat energy storage system is 0.3 MPa corresponding to heat release and 1 MPa corresponding to heat charging, and the working fluid circulation path is monitored and adjusted in real time through a pressure sensor.

8. The control method of the hot water-steam cogeneration sensible heat energy storage system based on the hot and cold alternating control strategy of claim 1 is characterized in that: The following steps are involved: Control steps of heating stage: (a) High-temperature steam is introduced into the energy storage device to detect the outlet working fluid temperature of the energy storage device in real time; (b) According to the comparison result between the outlet working fluid temperature and the preset temperature threshold, the three-way valve path is switched to allocate the working fluid flow direction: When the outlet working fluid temperature is lower than a first temperature threshold, directing the working fluid to a cold water tank; When the outlet working fluid temperature is between the first temperature threshold and the second temperature threshold, directing the working fluid to the medium temperature water tank; When the outlet working fluid temperature is between the second temperature threshold and the third temperature threshold, directing the working fluid to the hot water tank; (c) When the liquid level in the hot water tank reaches 75% of the full scale, open the power valve corresponding to the hot water tank to discharge the working fluid into the external circulation pipeline; Exothermic stage control steps: (d) Pumping normal temperature water from the external circulation pipeline into the cold water tank, maintaining the liquid level of the cold water tank at 75% of the full scale, pumping normal temperature water from the cold water tank into the energy storage device, and monitoring the liquid levels of the medium temperature water tank and the hot water tank in real time; (e) When the liquid level of the medium temperature water tank exceeds 50% of the full scale, the power valve corresponding to the medium temperature water tank is opened to introduce the working fluid into the external circulation pipeline for heat release; (f) When the liquid level in the hot water tank exceeds 50% of the full scale, the power valve corresponding to the hot water tank is opened to transport the working fluid to the energy storage device; (g) Dynamically adjust the working fluid distribution based on the comparison between the working fluid temperature at the outlet of the energy storage device and the steam generation threshold: When the liquid level in the hot water tank continuously exceeds 50% of the full scale during the heat release stage, the three-way valve path is switched alternately at a set time cycle, so that the working medium circulation between two or more energy storage devices and the water supply system is switched between the cold water tank and the hot water tank in an alternating order; When the working fluid in the cold water tank is used to circulate with the heat storage device, the outlet working fluid is distributed to the medium temperature water tank or the hot water tank according to the module outlet temperature; When the working fluid in the hot water tank and the heat storage device are circulated, if the outlet working fluid temperature reaches or exceeds the steam generation threshold, the working fluid is transported to the steam drum for steam-water separation, the separated steam is output, and the hot water is returned to the hot water tank; If the outlet working fluid temperature is lower than the steam generation threshold, the working fluid will be redistributed to the hot water tank for circulation heating.

9. The control method according to claim 8, characterized in that: During the charging stage, multiple energy storage devices are charged in sequence according to a preset order, and the working fluid with an outlet temperature higher than the temperature threshold is collected into a medium-temperature water tank or a hot water tank, and the medium-temperature and hot water tanks are used to preheat the modules with too low temperatures. During the heat release stage, multiple energy storage devices are connected in parallel through a header and a water supply tank, and the working fluid path is dynamically allocated according to the temperature difference of the working fluid at the outlet of each energy storage device. When the hot water tank and the cold water tank are used to alternately provide circulating working fluid for heat release, the steam drum is used to continuously output steam, and the medium-temperature water tank outputs hot water.

10. The control method according to claim 8, characterized in that: The first temperature threshold is 70°C, the second temperature threshold is 120°C, the third temperature threshold is 170°C, and the steam generation threshold is 133°C.

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