Thermal storage tank thermocline active regulation method and system

Abstract

The application provides a kind of thermal storage water tank thermocline active regulation method and system, belong to heat and power cogeneration thermal storage and temperature stratification control technical field, for the existing thermal storage water tank uses fixed position pumping and single thickness threshold start-stop, it is difficult to adapt to thermocline migration, and pumping process is easy to affect water balance and backwater temperature Problem, the temperature stratification and operating parameter of the present application are obtained, the boundary, thickness, position and evolution trend of thermocline are determined;According to the operating state and the position, thickness and evolution trend of thermocline, judge whether pumping is needed, and determine the target thickness, pumping position and target pumping flow when pumping is needed, transition mixed water under the constraint of water balance and mixed water transportation, and feedback correction according to the state of thermocline after pumping.The present application can improve the matching degree of pumping position and thermocline, reduce temperature stratification disturbance and control oscillation, maintain water balance and mixed water transportation safety.

Description

Technical Field

[0001] This invention belongs to the field of cogeneration thermal storage and temperature stratification control technology, specifically relating to an active regulation method and system for the inclined temperature layer of a hot water storage tank. Background Technology

[0002] Cogeneration units need to simultaneously meet the peak demand of the power grid and the heating network during operation. However, there is usually a strong coupling relationship between the unit's power generation load and heating load. With the increasing fluctuations in heating demand and grid load, it is difficult to balance power generation stability and heating continuity by simply adjusting the unit's steam extraction rate. Large hot water storage tanks can store hot water when the heating load is low or the unit has excess heat, and release the stored heat when the heating load increases. Therefore, they are widely used in the heat and power decoupling, peak heating, and peak heating processes of cogeneration units.

[0003] Hot water storage tanks typically utilize the density difference between water bodies at different temperatures to create temperature stratification. High-temperature water is located in the high-temperature side of the tank, while low-temperature water is located in the low-temperature side. A transitional zone with continuously changing temperatures exists between these two zones, commonly referred to as the thermocline. The thickness, location, and temperature gradient of the thermocline directly affect the effective volume of hot water that can be output at the set supply temperature from the hot water storage tank. During heat storage and release, the thermocline moves along the height of the tank along the direction of water inflow and outflow. When there are fluctuations in the inflow and outflow water flow, uneven water distribution, frequent switching of operating modes, or increased local water flow disturbance, the thermocline tends to thicken, further encroaching on the effective volume of the high-temperature and low-temperature stable zones, causing fluctuations in the outlet temperature of the hot water storage tank and a decrease in its effective heat storage capacity.

[0004] Existing hot water storage tanks typically suppress the mixing of hot and cold water by optimizing the structure of high-temperature and low-temperature water distribution components, reducing water flow velocity, and improving the flow field distribution within the tank. Temperature measuring points are also installed along the height of the tank to monitor the temperature distribution inside. These methods primarily focus on mitigating the formation or thickening of the thermocline, making it difficult to actively intervene in the temperature transition region after the thermocline has already abnormally thickened. Furthermore, some control methods rely mainly on the thickness of the thermocline or a single temperature difference to determine the stratification state, without comprehensively considering the upper and lower boundaries, center location, direction of movement, and thickness variation trend of the thermocline. Therefore, it is difficult to accurately distinguish between normal migration and abnormal thickening of the thermocline.

[0005] Furthermore, the position of the thermocline changes with heat storage, heat release, and operational condition switching. When using a fixed location for water extraction from the middle layer, the extraction location may deviate from the actual temperature transition zone, resulting in the extraction of water from either the high-temperature or low-temperature stable zones. Using fixed thresholds and valve start-stop methods for control can also easily lead to frequent start-stop cycles when the thermocline thickness approaches the threshold. Existing technologies lack a systematic consideration of the basis for determining the extraction flow rate, extraction duration, and extraction location, failing to adequately incorporate constraints such as the allowable temperature rise of the heating network's cold water, the transport capacity of the extraction pipeline, water flow disturbance within the tank, and the water balance of the hot water storage tank. Improperly setting the extraction flow rate not only makes it difficult to thin the thermocline but may also cause changes in the tank's liquid level, water entrapment in the stable zone, increased return water temperature, and further deterioration of temperature stratification.

[0006] Therefore, the existing control methods for the inclined temperature layer of hot water storage tanks still have problems such as incomplete state characterization, mismatch between the extraction location and the inclined temperature layer location, lack of constraints on the extraction flow rate, lack of distinction between control rules for different operating modes, and inability to effectively feed the control results back to the subsequent control process. These problems make it difficult to meet the heat storage and peak heating demand of cogeneration units under continuous variable operating conditions. Summary of the Invention

[0007] The present invention aims to solve at least one of the technical problems existing in the prior art, and provides a method and system for active regulation of the inclined temperature layer of a hot water storage tank.

[0008] This invention provides a method for actively regulating the inclined temperature layer of a hot water storage tank, comprising the following steps: S1: Obtain operating parameters used to characterize the operating status of the hot water storage tank; S2: Determine the position and thickness of the inclined temperature layer in the current control cycle based on the temperature distribution along the height of the hot water storage tank in the operating parameters, and obtain the evolution trend of the inclined temperature layer based on the position and thickness of the inclined temperature layer in the previous multiple consecutive control cycles. S3: Determine the operating status of the hot water storage tank based on the operating parameters, and determine whether it is necessary to extract transition mixed water from the inclined temperature layer based on the operating status, the position, thickness, and evolution trend of the inclined temperature layer; and, when extraction is required, determine the target thickness and extraction position of the inclined temperature layer, determine the target extraction flow rate based on the deviation of the current thickness of the inclined temperature layer from the target thickness, and limit the target extraction flow rate to a range within which the hot water storage tank can maintain water balance and the water temperature of the transition mixed water after it flows into the cold water pipeline of the heating network does not exceed the allowable value; S4: Extract the transition mixed water from the inclined temperature layer according to the extraction location and the target extraction flow rate and transport it to the heating network cold water pipeline, and adjust the inlet and outlet water flow rates of the hot water storage tank according to the actual extraction flow rate; S5: Based on the temperature distribution after extraction, redetermine the position and thickness of the inclined temperature layer, adjust the extraction position according to the redetermined position of the inclined temperature layer, and adjust the target extraction flow rate according to the deviation of the redetermined thickness of the inclined temperature layer from the target thickness. Extraction is stopped when the redetermined thickness is not higher than the target thickness and no longer increases, or when the hot water storage tank cannot maintain water balance, or when the water temperature of the cold water pipeline of the heating network exceeds the allowable value.

[0009] Furthermore, determining the position and thickness of the inclined temperature layer includes: identifying a high-temperature stable region, a low-temperature stable region, and a temperature transition region between them based on the temperature change with detection height in the temperature distribution; determining the boundary positions between the temperature transition region and the high-temperature stable region and the low-temperature stable region as the upper boundary and the lower boundary, respectively; determining the intermediate height between the upper boundary and the lower boundary as the position of the inclined temperature layer; and determining the height difference between the upper boundary and the lower boundary as the thickness of the inclined temperature layer.

[0010] Specifically, determining the evolution trend of the oblique temperature layer includes: comparing the center position and thickness of the oblique temperature layer determined in multiple consecutive control cycles, determining the movement direction of the oblique temperature layer based on the change in the center position, and determining a thickening trend, a thinning trend, or a stable trend based on the change in the thickness of the oblique temperature layer.

[0011] Specifically, the operating states include heat storage state, heat release state, static state, and operating condition switching state. Each operating state has a start threshold and a stop threshold, and the start threshold corresponding to the same operating state is greater than the stop threshold. When the thickness of the thermocline reaches the start threshold corresponding to the current operating state, or when it is determined from the evolution trend that the thickness will reach the start threshold within a preset time, it is determined that the transition mixed water needs to be extracted, and the stop threshold corresponding to the operating state is determined as the target thickness. When the thickness of the thermocline is not higher than the target thickness and no longer increases, it is determined that the thermocline has reached the target state.

[0012] Preferably, based on the center position of the inclined temperature layer, from a plurality of controlled extraction layers spaced apart along the height direction of the hot water storage tank, the controlled extraction layer located between the upper and lower boundaries of the inclined temperature layer and closest to the center position is selected, and the height of the selected controlled extraction layer is determined as the extraction position; when the boundary of the inclined temperature layer moves so that the selected controlled extraction layer is no longer located between the upper and lower boundaries, the process switches to another controlled extraction layer located between the updated upper and lower boundaries of the inclined temperature layer and closest to the updated center position; in this specification, the extraction layer among the plurality of extraction layers spaced apart along the height direction of the hot water storage tank that can be independently controlled in its connection state by a branch regulating valve is referred to as a controlled extraction layer.

[0013] Specifically, the basic drainage flow rate is determined based on the difference between the thickness of the inclined temperature layer and the target thickness, as well as the target control time. The basic drainage flow rate is then limited based on the allowable temperature rise of the heating network cold water pipeline, the conveying capacity of the drainage pipeline, the temperature stratification requirements inside the tank, and the inlet and outlet water regulation capacity of the hot water storage tank. The limited basic drainage flow rate is then determined as the target drainage flow rate.

[0014] Furthermore, the position and thickness of the inclined temperature layer are re-determined according to a preset control and evaluation cycle. The extraction position is adjusted based on the re-determined position, and the target extraction flow rate is adjusted based on the deviation of the re-determined thickness from the target thickness. The extraction flow rate is also adjusted based on the deviation between the actual extraction flow rate and the target extraction flow rate. Extraction is stopped when the thickness of the inclined temperature layer is not higher than the target thickness and no longer increases, or when the actual extraction flow rate continues to deviate from the target extraction flow rate and exceeds the allowable range, or when the liquid level of the hot water storage tank exceeds the allowable range.

[0015] Another aspect of the present invention provides an active temperature regulation system for a hot water storage tank, comprising: Hot water storage tanks are used to contain hot water and create temperature stratification. A high-temperature water distribution component is installed at the top of the hot water storage tank and connected to the high-temperature water inlet and outlet pipelines to guide high-temperature water into or out of the hot water storage tank. A low-temperature water distribution assembly is installed at the bottom of the hot water storage tank and connected to the low-temperature water inlet and outlet pipelines to guide low-temperature water into or out of the hot water storage tank. The inlet and outlet water regulating components are connected to the high-temperature water inlet and outlet pipes and the low-temperature water inlet and outlet pipes, respectively, and are used to regulate the inlet and outlet water flow of the hot water storage tank; A temperature detection component is provided along the height of the hot water storage tank to obtain the temperature distribution along the height of the hot water storage tank. The middle layer extraction assembly is located within the active range of the inclined temperature layer and has multiple controlled extraction layers spaced apart along the height direction of the hot water storage tank, for extracting transitional mixed water from the controlled extraction layers corresponding to the height range of the inclined temperature layer; The extraction pipeline is connected to the middle layer extraction assembly and is used to transport the transition mixed water; A flow regulation structure is installed on the pumping pipeline to regulate the pumping flow rate of the transition mixed water; A flow detection structure is installed on the pumping pipeline to detect the actual pumping flow rate of the transition mixed water; A mixed water receiving pipeline is connected to both the extraction pipeline and the unit heat exchange circuit, and is used to transport the transition mixed water to the unit heat exchange circuit; in this embodiment, the mixed water receiving pipeline is formed by the heating network cold water pipeline, the flow regulation structure adopts a flow regulating valve, and the flow detection structure adopts a flow sensor; and The control unit is connected to the inlet / outlet water regulating component, the temperature detection component, the middle layer pumping component, the flow regulating structure, and the flow detection structure, respectively. It is used to determine the current sloped temperature layer state, the sloped temperature layer evolution trend, and the target sloped temperature layer state based on the temperature distribution and the operating status of the hot water storage tank. Under the constraints of water balance conditions and mixed water transport conditions, it selects a controlled pumping layer and determines the target pumping flow rate based on the current sloped temperature layer state and the target sloped temperature layer state. It then pumps the transition mixed water according to the target pumping flow rate and coordinates the inlet / outlet water flow rates of the hot water storage tank based on the actual pumping flow rate. Finally, it corrects the selected controlled pumping layer and the target pumping flow rate based on the updated current sloped temperature layer state after pumping. The operating status of the hot water storage tank is determined based on the working status of the inlet / outlet water regulating component, which at least characterizes the fluid transport direction in the high-temperature water inlet / outlet pipeline and the low-temperature water inlet / outlet pipeline.

[0016] Furthermore, the middle-layer extraction assembly includes a plurality of annular extraction pipes spaced apart along the height direction of the hot water storage tank. The plurality of annular extraction pipes respectively constitute the plurality of controlled extraction layers. Each annular extraction pipe has a plurality of extraction holes spaced apart along the circumference and is connected to the extraction pipeline via an extraction branch equipped with a branch regulating valve. The branch regulating valve is connected to the control unit, and the temperature detection assembly is provided with temperature detection points at heights corresponding to the plurality of annular extraction pipes.

[0017] Specifically, the low-temperature water inlet and outlet pipelines are connected to the heating network cold water pipelines. The inlet and outlet water regulating assembly includes a cold water pump installed on the heating network cold water pipeline, and the pumping pipeline is connected to the inlet side of the cold water pump. The pumping pipeline is equipped with a flow regulating valve, a flow sensor, and an anti-backflow structure. The anti-backflow structure is used to prevent water in the heating network cold water pipeline from flowing back into the pumping pipeline. The control unit adjusts the flow regulating valve according to the deviation between the actual pumping flow rate detected by the flow sensor and the target pumping flow rate.

[0018] The beneficial effects of this invention are as follows: This invention identifies the boundaries, thickness, location, and evolution trend of the thermocline, determines whether drainage is necessary based on the operating status of the hot water storage tank, identifies the target thickness, and selects a controlled drainage layer matching the height range of the thermocline. Simultaneously, it determines the drainage flow rate under constraints of the allowable temperature rise of the heating network chilled water, pipeline transport capacity, internal tank temperature stratification, and water balance. The drainage location and flow rate are then corrected based on feedback from the temperature distribution after drainage. This reduces the accidental drainage of water in stable temperature zones and the disturbance to temperature stratification during drainage, suppresses control oscillations, maintains the liquid level in the hot water storage tank and ensures the safety of mixed water transport, and allows the heat carried by the transition mixed water to continue entering the unit's heat exchange circuit for utilization, which is beneficial for restoring effective temperature stratification and effective heat storage volume. Attached Figure Description

[0019] Figure 1 This is a flowchart illustrating the steps of an active temperature control method for a hot water storage tank according to a specific embodiment of the present invention. Figure 2 This is a schematic diagram of the structure and pipeline connection of an active temperature control system for a hot water storage tank according to a specific embodiment of the present invention.

[0020] Among them, 1 is a hot water pump, 2 is a first electrically controlled regulating valve, 3 is an upper water distributor, 4 is a hot water storage tank, 5 is a cold water pump, 6 is a second electrically controlled regulating valve, 7 is a flow sensor, 8 is an anti-backflow check valve, 9 is an intermediate water distributor, 10 is a third electrically controlled regulating valve, 11 is a lower water distributor, 12 is a temperature sensor, 13 is a heating network cold water pipeline, and 14 is a pumping pipeline. Detailed Implementation

[0021] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] like Figure 1 As shown in the figure, a method for active regulation of the inclined temperature layer in a hot water storage tank provided by a specific embodiment of the present invention includes the following steps: S1: Obtain operating parameters used to characterize the operating status of the hot water storage tank; S2: Determine the position and thickness of the inclined temperature layer in the current control cycle based on the temperature distribution along the height of the hot water storage tank in the operating parameters, and obtain the evolution trend of the inclined temperature layer based on the position and thickness of the inclined temperature layer in the previous multiple consecutive control cycles. S3: Determine the operating status of the hot water storage tank based on the operating parameters, and determine whether it is necessary to extract transition mixed water from the inclined temperature layer based on the operating status, the position, thickness, and evolution trend of the inclined temperature layer; and, when extraction is required, determine the target thickness and extraction position of the inclined temperature layer, determine the target extraction flow rate based on the deviation of the current thickness of the inclined temperature layer from the target thickness, and limit the target extraction flow rate to a range within which the hot water storage tank can maintain water balance and the water temperature of the transition mixed water after it flows into the cold water pipeline of the heating network does not exceed the allowable value; S4: Extract the transition mixed water from the inclined temperature layer according to the extraction location and the target extraction flow rate and transport it to the heating network cold water pipeline, and adjust the inlet and outlet water flow rates of the hot water storage tank according to the actual extraction flow rate; S5: Based on the temperature distribution after extraction, redetermine the position and thickness of the inclined temperature layer. Adjust the extraction position according to the redetermined position of the inclined temperature layer, and adjust the target extraction flow rate according to the deviation of the redetermined thickness of the inclined temperature layer from the target thickness. Extraction is stopped when the redetermined thickness is not higher than the target thickness and no longer increases, or when the hot water storage tank cannot maintain water balance, or when the water temperature of the cold water pipeline in the heating network exceeds the allowable value. The target thickness is determined based on the current operating state of the hot water storage tank. The heat storage state, heat release state, static state, and operating condition switching state correspond to the start-up threshold and stop threshold, respectively. When it is determined that transitional mixed water needs to be extracted, the stop threshold corresponding to the current operating state is determined as the target thickness. When the operating state of the hot water storage tank changes, the target thickness is redetermined based on the changed operating state.

[0023] In one embodiment, the operating parameters include temperature data obtained by the temperature detection component at different detection heights, the flow direction and flow rate of high-temperature and low-temperature water in the hot water storage tank, the liquid level of the hot water storage tank, the actual pumping flow rate of the transition mixed water, and the cold water temperature, cold water flow rate, and pipeline pressure in the mixed water receiving pipeline. These operating parameters are updated according to a control cycle to determine the temperature stratification state, operating state, and transition mixed water delivery state of the hot water storage tank at the same time reference. In this embodiment, the position of the inclined temperature layer is represented by the intermediate height between the upper and lower boundaries of the inclined temperature layer; the height range of the inclined temperature layer refers to the height interval between the upper and lower boundaries of the inclined temperature layer. The target state of the inclined temperature layer includes at least a thickness that is not higher than the target thickness and does not increase further, where the target thickness is the stop threshold corresponding to the current operating state. The mixed water receiving pipeline is composed of the cold water pipeline 13 of the heating network connected to the unit's heat exchange circuit.

[0024] Specifically, the operating state of the hot water storage tank is determined based on the fluid transport direction in the high-temperature water inlet / outlet pipes and the low-temperature water inlet / outlet pipes. When high-temperature water enters from the top of the hot water storage tank and low-temperature water flows out from the bottom, it is determined to be in a heat storage state; when low-temperature water enters from the bottom of the hot water storage tank and high-temperature water flows out from the top, it is determined to be in a heat release state; when there is no flow in either the high-temperature or low-temperature water inlet / outlet pipes that would cause net charging and heat release in the hot water storage tank, it is determined to be in a static state; when the fluid transport direction, inlet / outlet water flow rate, or valve operating state changes from one operating state to another, it is determined to be in a condition switching state. It should be noted that the operating state of the hot water storage tank is used to determine the current temperature stratification requirements and the target state of the inclined temperature layer, and does not necessarily indicate that the current operating state allows for the extraction of transitional mixed water. Whether extraction is allowed should also be determined based on the operating direction of the cold water pump 5, the pressure at the confluence of the extraction pipe 14 and the cold water pipe 13 of the heating network, and the transport state of the mixed water receiving pipe. The control unit generates a target pumping flow rate greater than zero only when the pumping line 14 has a delivery pressure differential from the middle pumping assembly to the heating network chilled water line 13.

[0025] Furthermore, the water balance condition is used to limit the difference between the total inflow, total outflow, and transitional mixed water pumping rate of the hot water storage tank per unit time, so that the liquid level in the hot water storage tank is maintained within the allowable range. Let the total inflow rate of the hot water storage tank be... The total outflow rate, excluding the flow rate of the transition mixed water pumping, is The actual pumping flow rate is Then the rate of change of volume of the hot water storage tank satisfies:

[0026] The control unit adjusts the inlet and outlet water flow rates of the hot water storage tank to keep the volume change rate within the range corresponding to the allowable fluctuation range of the liquid level. The mixed water delivery conditions limit the flow direction, receiving temperature, delivery flow rate, and available pressure differential during the transition mixed water delivery process. When the mixed water receiving pipeline lacks sufficient temperature, flow rate, or delivery pressure differential to receive the transition mixed water, pumping is not performed or ongoing pumping is stopped. In the heat storage state, the pumped amount of transition mixed water is included in the total outflow of the hot water storage tank, and the control unit correspondingly reduces the low-temperature water outflow rate at the bottom of the tank or increases the high-temperature water inflow rate at the top. In the heat release state, the control unit correspondingly increases the low-temperature water inflow rate at the bottom of the tank or decreases the high-temperature water outflow rate at the top. In the static state, pumping is only performed when there is makeup water matching the temperature of the stable temperature zone being entered, and the makeup water flow rate can compensate for the actual pumping flow rate. The adjustment method is determined by the current operating state and the flow requirements on the heating side, and is constrained by maintaining the liquid level of the hot water storage tank and the predetermined heating flow rate.

[0027] Based on the above basic implementation method, a high-temperature stable zone, a low-temperature stable zone, and a temperature transition zone are identified according to the temperature sequence in the height direction of the hot water storage tank. The upper boundary and lower boundary of the inclined temperature layer are determined according to the boundary positions between the temperature transition zone and the high-temperature stable zone and the low-temperature stable zone, respectively. The center position and thickness of the inclined temperature layer are determined according to the upper boundary and the lower boundary of the inclined temperature layer.

[0028] Furthermore, using the bottom of the hot water storage tank as the origin of the height coordinate system, the effective temperature data obtained by the temperature detection component are arranged into a temperature sequence according to the detection height from low to high. ,in, Indicates the first The temperature detection position is located at the height of the bottom of the hot water storage tank. This indicates the water temperature at the temperature detection location. A high-temperature stability zone is determined based on continuous detection locations located at the top of the tank where temperature changes are gradual. The representative high-temperature temperature is then determined based on the effective temperature data within this stable zone. The low-temperature stability zone is determined based on continuous monitoring locations at the bottom of the tank where temperature changes are gradual, and the representative low-temperature temperature is determined based on the effective temperature data within the low-temperature stability zone. .

[0029] Furthermore, starting from the high-temperature stable zone, the temperature at each detection location is determined sequentially downwards. When the boundary temperature difference threshold is reached, the height of the upper boundary of the thermocline is determined based on the detection location and its adjacent detection locations. ; Determine the temperature of each detection location sequentially upwards from the low-temperature stable zone, when When the boundary temperature difference threshold is reached, the lower boundary height of the thermocline is determined based on the detection location and its adjacent detection locations. When the detection location does not coincide with the boundary, the boundary height is determined by interpolation based on the temperature and height of adjacent detection locations. (Temperature layer thickness) and central position Determine them according to the following formulas respectively:

[0030] thus, This represents the temperature of the high-temperature stability region. This represents the temperature of the low-temperature stable region. Indicates the first Temperature at each temperature detection location Indicates the height of the upper boundary of the thermocline. Indicates the height of the lower boundary of the thermocline. Indicates the thickness of the thermocline. This indicates the midpoint between the upper and lower boundaries of the thermocline, i.e., the position of the thermocline. To verify the continuity of the temperature transition zone, the temperature gradient between adjacent detection locations is calculated:

[0031] When the temperature at a set of consecutive detection locations falls between the high-temperature representative temperature and the low-temperature representative temperature, and the temperature gradient between adjacent detection locations reaches the temperature transition zone criterion, the height range corresponding to this set of detection locations is defined as the temperature transition zone. The boundary temperature difference criterion and the temperature gradient criterion are used together to exclude localized temperature abrupt changes at individual detection locations within the high-temperature stable zone or the low-temperature stable zone.

[0032] During data preprocessing, temperature data undergoes measurement range verification, adjacent control cycle variation verification, and adjacent detection height consistency verification. When data from a single temperature detection location is abnormal while data from its upper and lower adjacent detection locations are valid, the abnormal data is interpolated and replaced based on the data from the adjacent detection locations. When data from multiple consecutive temperature detection locations is abnormal, or when the valid temperature data is insufficient to determine the high-temperature stable zone, low-temperature stable zone, and temperature transition zone, the slope temperature layer identification result for this control cycle is marked as invalid. The pumping flow rate is not started or increased based on this identification result, and the previous valid control state is maintained or pumping is stopped.

[0033] In one specific embodiment, determining the evolution trend of the oblique temperature layer includes: comparing the center position and thickness of the oblique temperature layer determined in multiple consecutive control cycles, determining the movement direction of the oblique temperature layer based on the change in the center position, and determining a thickening trend, a thinning trend, or a stable trend based on the change in the thickness of the oblique temperature layer.

[0034] In this embodiment, the first The center position and thickness of the hydrothermal layer determined in each control cycle are denoted as follows: and Based on the effective identification results of multiple consecutive control cycles, the rate of change of the position and thickness of the thermocline were determined:

[0035] In the formula, The number of consecutive control cycles participating in the comparison. To control the cycle duration, the rate of position change is... The positive or negative sign is used to characterize the upward or downward movement of the thermocline and the rate of thickness change. The positive or negative sign is used to characterize whether the thermocline is thickening or thinning.

[0036] Furthermore, to avoid frequent changes in the evolution trend of the inclined temperature layer due to temperature measurement fluctuations, separate judgment ranges for position change and thickness change are set. When the position change does not exceed the judgment range, the position of the inclined temperature layer is determined to be stable; when the thickness change does not exceed the judgment range, the inclined temperature layer is determined to be in a stable trend. Only when the change direction is consistent across multiple consecutive control cycles, or when the total change determined based on multiple consecutive control cycles exceeds the corresponding judgment range, is the movement direction or thickness change trend of the inclined temperature layer updated. In the heat storage state, the downward movement of the inclined temperature layer as high-temperature water enters from the top of the tank is expected migration; in the heat release state, the upward movement of the inclined temperature layer as low-temperature water enters from the bottom of the tank is expected migration; in the static state, the continuous movement of the center position of the inclined temperature layer or the continuous increase in thickness indicates a change in temperature stratification; in the operating condition switching state, the evolution trend of the inclined temperature layer is re-determined after the inflow and outflow water flows stabilize and multiple effective temperature distributions are obtained. Therefore, the movement of the inclined temperature layer itself is not directly used as a trigger condition for pumping, but is judged together with the thickness change, the movement direction, and the stratification requirements corresponding to the current operating state.

[0037] In another specific embodiment, the operating states include a heat storage state, a heat release state, a static state, and a condition switching state. Each operating state has a start threshold and a stop threshold, and the start threshold corresponding to the same operating state is greater than the stop threshold. When the thickness of the thermocline reaches the start threshold corresponding to the current operating state, or when it is determined that the thickness will reach the start threshold within a preset control period based on the evolution trend of the thermocline, it is determined that transition mixed water needs to be extracted, and the stop threshold corresponding to this operating state is determined as the target thickness. When the thickness of the thermocline is not higher than the target thickness and no longer increases, it is determined that the thermocline has reached the target state.

[0038] In this embodiment, the heat storage state, heat release state, static state, and operating condition switching state are each configured with start-up and stop thresholds adapted to the corresponding water flow direction and temperature stratification characteristics. The thresholds for each operating state are set independently, with the start-up threshold for the same operating state being higher than the stop threshold, thus creating a hysteresis range between starting and stopping pumping. When the thermocline thickness is within this hysteresis range, the current control state is maintained to avoid frequent opening and closing of the branch regulating valves due to fluctuations in the thermocline thickness around a single threshold.

[0039] Specifically, when the inclined temperature layer has not yet reached the start-up threshold corresponding to the current operating state, but it is determined based on the thickness change rate that the inclined temperature layer will reach the start-up threshold within a preset control period, a control target for the inclined temperature layer is generated in advance. The predicted thickness can be determined by the sum of the current inclined temperature layer thickness and the increment of the thickness change rate within the preset control period. The target state of the inclined temperature layer includes at least the thickness not exceeding the stop threshold corresponding to the current operating state and the thickness no longer increasing; when the center position of the inclined temperature layer exceeds the coverage range of the middle layer extraction component or the temperature gradient has not recovered to the stratification requirements corresponding to the current operating state, control is maintained or the extraction position is switched, and control is not terminated based on a single thickness measurement result; in the state of operating condition switching, when the flow direction in the high-temperature water inlet / outlet pipe or the low-temperature water inlet / outlet pipe is not yet stable, extraction is not started based on the change in the inclined temperature layer position in a single control cycle; the control unit maintains the original control level, reduces the target extraction flow rate, or suspends extraction, and re-determines the start-up threshold, stop threshold, and inclined temperature layer target state based on the new operating state after the flow direction stabilizes.

[0040] In another specific embodiment, based on the center position of the inclined temperature layer, from a plurality of controlled extraction layers spaced apart along the height direction of the hot water storage tank, the controlled extraction layer located between the upper and lower boundaries of the inclined temperature layer and closest to the center position is selected, and the height of the selected controlled extraction layer is determined as the extraction position; when the boundary of the inclined temperature layer moves so that the selected controlled extraction layer is no longer located between the upper and lower boundaries, the system switches to another controlled extraction layer located between the updated upper and lower boundaries of the inclined temperature layer and closest to the updated center position.

[0041] Furthermore, the height of the multiple controlled extraction layers covers the activity range of the inclined temperature layer in heat storage, heat release, and operating condition switching states. The height interval between adjacent controlled extraction layers is determined by the minimum inclined temperature layer thickness that needs to be identified and controlled, ensuring that at least one controlled extraction layer exists between the upper and lower boundaries of the inclined temperature layer when it is within its normal activity range. Each controlled extraction layer is connected to the extraction pipeline 14 via an independent extraction branch, thereby allowing the control unit to individually control the connection status between each controlled extraction layer and the extraction pipeline 14.

[0042] Specifically, the control unit only opens the branch regulating valve connected to the selected controlled pumping layer and closes the branch regulating valves corresponding to the other controlled pumping layers, so that the pumping flow is concentrated on the temperature transition zone of the thermocline. While the current controlled pumping layer is still located between the upper and lower boundaries of the thermocline, it remains connected. When the thermocline moves and causes the current controlled pumping layer to enter a high-temperature or low-temperature stable zone, the current controlled pumping layer is closed, and the system switches to another controlled pumping layer that is still located between the upper and lower boundaries of the thermocline and is closest to the center of the thermocline. When there is no controlled pumping layer located between the upper and lower boundaries of the thermocline, pumping stops to avoid drawing water from the high-temperature or low-temperature stable zone.

[0043] In another specific embodiment, the basic pumping flow rate is determined based on the difference between the thickness of the inclined temperature layer and the target thickness corresponding to the target state of the inclined temperature layer, as well as the target adjustment time. The upper limit of the pumping flow rate is determined based on the allowable temperature rise of the mixed water receiving pipeline, the conveying capacity of the pumping pipeline 14, and the allowable pumping flow rate for maintaining the temperature stratification inside the tank. The smaller value between the basic pumping flow rate and the upper limit of the pumping flow rate is determined as the target pumping flow rate.

[0044] Furthermore, the volume of the transition zone that needs to be regulated is determined based on the difference between the current thickness and the target thickness of the thermocline. For a hot water storage tank with a cross-sectional area that remains constant along the height direction, the cross-sectional area of ​​the hot water storage tank is denoted as... The current thickness of the thermocline is denoted as The target thickness is denoted as The volume of the transition region that needs to be regulated. Determined according to the following formula:

[0045] Based on the target adjustment time Determine the basic pumping flow rate:

[0046] The basic pumping flow rate is used as the initial set value for the pumping flow rate, and is subsequently corrected based on changes in the thermocline. The calculated result of the transition zone volume is not directly regarded as the final amount of water that needs to be pumped out. For hot water storage tanks whose cross-sectional area varies with height, the transition zone volume that needs to be adjusted is determined by integrating the cross-sectional area of ​​the tank between the current boundary and the target boundary of the thermocline along the height.

[0047] Specifically, the flow rate and temperature of the cold water upstream of the pumping point in the mixed water receiving pipeline are respectively denoted as... and The pumping flow rate and temperature of the transition mixed water are denoted as follows: and The temperature of the mixed water Determined according to the following formula:

[0048] When the maximum allowable receiving temperature of the unit's heat exchange circuit is At that time, Not higher than .when At that time, the upper limit of the pumping flow rate is determined by the allowable temperature rise. satisfy:

[0049] when Has reached or exceeded When this occurs, the pumping of transition mixed water into the mixed water receiving pipeline is stopped; the upper limit of the flow rate corresponding to the conveying capacity of the pumping pipeline 14 is denoted as... The maximum flow rate allowed to maintain temperature stratification within the tank is denoted as The aforementioned The upper limit of the pumping flow rate is determined based on the total flow area of ​​the pumping holes in the controlled pumping layer, the allowable pumping velocity, and the allowable inlet and outlet flow velocities of the high-temperature and low-temperature water distribution components. The upper limit of the pumping flow rate, determined by the inlet and outlet water regulation capacity of the hot water storage tank under the current operating conditions, is denoted as... The aforementioned The target discharge flow rate is determined based on the increase in inflow rate and the reduction in other outflow rates that the hot water storage tank can handle, and is used to limit the net outflow from the hot water storage tank caused by the extraction of transitional mixed water; the target discharge flow rate is determined according to the following formula and modified as follows:

[0050] When the temperature of the transition mixed water does not constitute a receiving temperature limit, it shall not be used. As a limiting condition for the current control cycle; when the inlet and outlet water regulation capacity of the hot water storage tank is sufficient to compensate for the basic pumping flow, it is not subject to... The base pumping flow rate is further reduced. Excessive pumping flow rate can easily entrain water from high-temperature or low-temperature stable zones, causing temperature stratification disturbances; insufficient pumping flow rate cannot achieve a identifiable control effect within the target control time. Therefore, the control unit adjusts the flow regulation structure based on the deviation between the actual and target pumping flow rates, and corrects the target pumping flow rate through subsequent feedback from the thermocline state.

[0051] In another specific embodiment, the position and thickness of the inclined thermosphere are re-determined according to a preset control evaluation cycle. The extraction position is adjusted based on the re-determined position, and the target extraction flow rate is adjusted based on the deviation of the re-determined thickness from the target thickness. The deviation between the actual extraction flow rate and the target extraction flow rate is used to adjust the opening of the flow regulation structure and is not directly used as the basis for changing the target extraction flow rate. Extraction is stopped when the thickness of the inclined thermosphere is not higher than the target thickness and no longer increases, or when the actual extraction flow rate continues to deviate from the target extraction flow rate and exceeds the allowable range, or when the liquid level in the hot water storage tank exceeds the allowable range.

[0052] Furthermore, the preset control evaluation cycle includes multiple temperature sampling cycles, which are longer than the response time required for the flow regulation structure to complete one opening adjustment. At the end of each control evaluation cycle, the control unit re-determines the upper boundary, lower boundary, center position, and thickness of the thermocline, and compares the updated thermocline thickness deviation, center position change, and thickness change trend with the results of the previous control evaluation cycle. When the thermocline thickness decreases towards the target thickness and the temperature stratification does not worsen, the current controlled extraction layer and target extraction flow rate are maintained; when the actual extraction flow rate does not reach the target extraction flow rate, the flow regulation structure is adjusted first; when the actual extraction flow rate has reached the target extraction flow rate but the thermocline has not thinned, the target extraction flow rate is increased within the upper limit of the extraction flow rate or the control extraction layer is switched to a position closer to the center of the thermocline.

[0053] Specifically, when the thickness of the inclined temperature layer continues to increase after drainage, the temperature gradient decreases, or the ranges of the high-temperature stable zone and the low-temperature stable zone shrink simultaneously, it is determined that drainage has an adverse effect on temperature stratification, and the target drainage flow rate is reduced; if the situation does not improve after reducing the target drainage flow rate, drainage is stopped. When the temperature detection data is insufficient to re-determine the inclined temperature layer state, the deviation between the actual drainage flow rate and the target drainage flow rate continues to exceed the allowable range of flow control, the temperature of the mixed water receiving pipeline exceeds the limit, the drainage drive pressure differential is insufficient, backflow occurs, or the liquid level of the hot water storage tank exceeds the allowable range, the control level is no longer increased, and drainage is stopped. The above abnormal judgments are used to limit state identification, flow correction, and drainage execution, and are not considered as independent interlocking processes unrelated to inclined temperature layer control; the current inclined temperature layer state continuously meeting the inclined temperature layer target state means that within multiple consecutive control evaluation cycles, the inclined temperature layer thickness is not higher than the target thickness, the inclined temperature layer thickness does not show an increasing trend, and the center position of the inclined temperature layer is within the coverage range of the middle layer drainage component or the allowable position range corresponding to the current operating state. Once the above conditions are met, the control unit gradually reduces the target pumping flow rate and closes the corresponding branch regulating valves to avoid fluctuations in pipeline flow caused by sudden cessation of pumping.

[0054] In one specific embodiment, a hot water storage tank inclined temperature layer active control system is provided, comprising: Hot water storage tanks are used to contain hot water and create temperature stratification. A high-temperature water distribution component is installed at the top of the hot water storage tank and connected to the high-temperature water inlet and outlet pipelines to guide high-temperature water into or out of the hot water storage tank. A low-temperature water distribution assembly is installed at the bottom of the hot water storage tank and connected to the low-temperature water inlet and outlet pipelines to guide low-temperature water into or out of the hot water storage tank. The inlet and outlet water regulating components are connected to the high-temperature water inlet and outlet pipes and the low-temperature water inlet and outlet pipes, respectively, and are used to regulate the inlet and outlet water flow of the hot water storage tank; A temperature detection component is provided along the height of the hot water storage tank to obtain the temperature distribution along the height of the hot water storage tank. The middle layer extraction assembly is located within the active range of the inclined temperature layer and has multiple controlled extraction layers spaced apart along the height direction of the hot water storage tank, for extracting transitional mixed water from the controlled extraction layers corresponding to the height range of the inclined temperature layer; The extraction pipeline is connected to the middle layer extraction assembly and is used to transport the transition mixed water; A flow regulation structure is installed on the pumping pipeline to regulate the pumping flow rate of the transition mixed water; A flow detection structure is installed on the pumping pipeline to detect the actual pumping flow rate of the transition mixed water; A mixed water receiving pipeline, connected to both the extraction pipeline and the unit heat exchange circuit, is used to transport the transition mixed water to the unit heat exchange circuit; and The control unit is connected to the inlet / outlet water regulating component, temperature detection component, middle layer pumping component, flow regulating structure, and flow detection structure, respectively. It is used to determine the current sloped temperature layer state, sloped temperature layer evolution trend, and sloped temperature layer target state based on the temperature distribution and the operating status of the hot water storage tank. Under the constraints of water balance and mixed water delivery conditions, it selects a controlled pumping layer and determines the target pumping flow rate based on the current sloped temperature layer state and the target sloped temperature layer state. It then pumps the transition mixed water according to the target pumping flow rate and coordinates the inlet / outlet water flow rates of the hot water storage tank based on the actual pumping flow rate. Finally, it corrects the selected controlled pumping layer and the target pumping flow rate based on the updated current sloped temperature layer state after pumping. In this embodiment, the flow regulating structure uses a flow regulating valve, specifically a second electrically controlled regulating valve 6, installed on the pumping pipeline 14; the flow detection structure uses a flow sensor 7; and the mixed water receiving pipeline is composed of the heating network cold water pipeline 13. The low-temperature water inlet and outlet pipelines are connected to the heating network cold water pipeline 13. The inlet and outlet water regulating component includes a cold water pump 5 installed on the heating network cold water pipeline 13, and the pumping pipeline 14 is connected to the inlet side of the cold water pump 5.

[0055] In this embodiment, the control unit is composed of a power plant DCS control system. The temperature detection component, inlet / outlet water regulation component, intermediate layer pumping component, and flow regulation structure are connected to the DCS control system via signal lines or an industrial communication network. The temperature detection component provides the control unit with temperature data at different detection heights; the inlet / outlet water regulation component provides the control unit with the inlet and outlet water flow rates and directions of the hot water storage tank; the intermediate layer pumping component provides the control unit with the connectivity status of the controlled pumping layer; and the flow regulation structure receives pumping flow rate regulation commands output by the control unit.

[0056] Specifically, the control unit determines the height range of the inclined temperature layer based on the temperature distribution obtained by the temperature detection component, selects the controlled extraction layer in the middle layer extraction component according to this height range, and connects the selected controlled extraction layer to the extraction pipeline 14 through the corresponding branch regulating valve; the flow regulation structure adjusts the delivery flow rate of the transition mixed water according to the target extraction flow rate, and the inlet and outlet water regulation component compensates the inlet and outlet water flow rates of the hot water storage tank according to the actual extraction flow rate. The temperature distribution after extraction is again fed back to the control unit by the temperature detection component, thus forming a closed loop of inclined temperature layer status identification, transition mixed water extraction, and regulation result feedback between the temperature detection component, the middle layer extraction component, the extraction pipeline 14, the flow regulation structure, and the inlet and outlet water regulation component.

[0057] In one specific embodiment, the middle-layer extraction assembly includes a plurality of annular extraction pipes spaced apart along the height direction of the hot water storage tank. The plurality of annular extraction pipes respectively constitute the plurality of controlled extraction layers. Each annular extraction pipe has a plurality of extraction holes spaced apart along the circumference and is connected to the extraction pipeline 14 via an extraction branch equipped with a branch regulating valve. The branch regulating valve is connected to the control unit, and the temperature detection assembly is provided with temperature detection points at heights corresponding to the plurality of annular extraction pipes.

[0058] Furthermore, each annular extraction pipe is arranged along the cross-sectional direction of the hot water storage tank, and multiple extraction holes are distributed circumferentially along the annular extraction pipe. The opening direction of the extraction holes is set to the horizontal direction, so that the transitional mixed water enters the annular extraction pipe from different circumferential positions of the same controlled extraction layer, reducing vertical flow and temperature stratification disturbances caused by local concentrated extraction. The extraction branches of each annular extraction pipe converge into the same extraction pipeline 14, and the branch regulating valves on each extraction branch remain independently controlled.

[0059] Furthermore, the temperature detection component sets temperature detection points at the installation height of each annular extraction pipe or at adjacent positions above and below the installation height to determine whether the annular extraction pipe is currently in the high-temperature stable zone, low-temperature stable zone, or temperature transition zone. The control unit only connects the annular extraction pipe located in the temperature transition zone to the extraction pipeline 14. When the center of the inclined temperature layer is located between two annular extraction pipes, the annular extraction pipe that is still located between the upper and lower boundaries of the inclined temperature layer and has a small height difference from the center position is selected; when the height difference between the two annular extraction pipes and the center position is the same, the currently connected annular extraction pipe that is still located in the temperature transition zone is maintained to reduce the number of branch regulating valve switching times.

[0060] In one specific embodiment, the low-temperature water inlet / outlet pipeline is connected to the heating network cold water pipeline, and the mixed water receiving pipeline is connected to the heating network cold water pipeline; the inlet / outlet water regulating component includes a cold water pump 5 installed on the heating network cold water pipeline, and the connection position of the pumping pipeline 14 to the heating network cold water pipeline is located on the inlet side of the cold water pump 5; the pumping pipeline 14 is provided with the flow regulating structure, the flow detection structure, and the anti-backflow structure, the anti-backflow structure is used to prevent water in the heating network cold water pipeline from flowing back to the pumping pipeline 14, the flow detection structure is connected to the control unit, and the control unit adjusts the flow regulating structure according to the deviation between the actual pumping flow rate and the target pumping flow rate.

[0061] Specifically, during operation, the cold water pump 5 generates a suction pressure at its inlet side that is lower than the pressure at the middle layer of the hot water storage tank's pumping position. The pressure difference between the middle layer of the hot water storage tank's pumping position and the inlet side of the cold water pump 5 constitutes the driving force for pumping out the transitional mixed water. The pressure at the selected controlled pumping layer within the hot water storage tank is denoted as... The pressure at the connection point between the extraction pipe 14 and the cold water pipe of the heating network is recorded as . The pressure loss along and in local areas of the extraction pipeline 14 is denoted as... The opening pressure difference of the anti-backflow structure is denoted as Then, the following conditions must be met when performing the extraction:

[0062] The pumping drive pressure difference is formed when the operating direction of the cold water pump 5 causes the merging point of the pumping pipeline 14 and the heating network cold water pipeline 13 to be located on the inlet side of the cold water pump 5. The tank pressure at the selected controlled extraction layer, the The pressure at the inlet side of the cold water pump 5, where the water is drawn into the pump, is... To account for the pressure losses along the pipe and in the local area caused by the pumping pipeline 14, the flow regulation structure, and the flow detection structure under the current target pumping flow rate, the... To prevent backflow, the pressure differential at the start of the structure is controlled. When this pressure differential condition is met, the transition mixed water flows sequentially through the controlled pumping layer, pumping branch, pumping pipeline 14, and the anti-backflow structure into the heating network chilled water pipeline, and is then transported to the unit's heat exchange circuit by the chilled water pump 5. This embodiment does not require a separate pumping pump. When the chilled water pump 5 stops operating, or when the operating direction of the chilled water pump 5 changes so that the merging position of the pumping pipeline 14 cannot form the aforementioned pumping drive pressure differential, the control unit determines that the mixed water delivery conditions are not met, sets the target pumping flow rate to zero, and closes the flow regulation structure and the corresponding branch regulating valve. At this time, the anti-backflow structure prevents water in the heating network chilled water pipeline 13 from entering the middle-layer pumping assembly and the hot water storage tank 4 via the pumping pipeline 14.

[0063] Furthermore, the allowed flow direction of the anti-backflow structure is from the middle-layer extraction assembly to the heating network cold water pipeline, and it is located near the heating network cold water pipeline in the extraction pipeline 14. When the cold water pump 5 stops operating, the pressure on the inlet side of the cold water pump 5 increases, or the pressure in the heating network cold water pipeline is higher than the pressure at the middle-layer extraction position of the hot water storage tank, the anti-backflow structure closes, preventing the heating network cold water from entering the extraction pipeline 14 and the hot water storage tank. The control unit adjusts the flow regulation structure according to the actual extraction flow detected by the flow detection structure; when the opening of the flow regulation structure increases but the actual extraction flow still cannot reach the target extraction flow, it is determined that the current extraction drive pressure difference is insufficient, and the branch regulating valve and the flow regulation structure are closed, without forcibly extracting by continuously increasing the valve opening; the mixed water receiving pipeline constitutes the transmission path for the transition mixed water to enter the heating network cold water pipeline from the extraction pipeline 14 and to the unit heat exchange circuit. The junction of the extraction pipeline 14 and the heating network chilled water pipeline is located at the inlet side of the chilled water pump 5, allowing the transition mixed water to mix with the heating network chilled water first, and then be sent into the unit's heat exchange circuit by the chilled water pump 5. The heat carried by the transition mixed water is not directly discharged from the thermal system, but enters the unit's heat exchange circuit with the mixed chilled water to continue participating in heat exchange; its mixing temperature is limited according to the aforementioned heat balance relationship.

[0064] In one specific implementation, such as Figure 2 As shown, the upper water distributor 3 is located at the top of the hot water storage tank 4, the lower water distributor 11 is located at the bottom of the hot water storage tank 4, and the middle water distributor 9 is located in the middle temperature transition zone of the hot water storage tank 4. The upper water distributor 3, the lower water distributor 11, and the middle water distributor 9 all adopt an annular porous structure arranged along the cross-sectional direction of the hot water storage tank 4, so that the water flows in a dispersed manner along the circumference, reducing the disturbance of local concentrated water inflow or pumping to the temperature stratification inside the tank.

[0065] Hot water pump 1 is connected to upper water distributor 3 via high-temperature water inlet and outlet pipes. A first electrically controlled regulating valve 2 is located between hot water pump 1 and upper water distributor 3 to regulate the flow rate of high-temperature water into and out of hot water storage tank 4. In heat storage mode, high-temperature water enters the upper part of hot water storage tank 4 through the first electrically controlled regulating valve 2 and upper water distributor 3 under the action of hot water pump 1. In heat release mode, the high-temperature water in the upper part of hot water storage tank 4 is transported outwards through upper water distributor 3, first electrically controlled regulating valve 2, and high-temperature water inlet and outlet pipes.

[0066] The cold water pump 5 is connected to the lower water distributor 11 via the heating network cold water pipeline 13. The third electrically controlled regulating valve 10 is located between the cold water pump 5 and the lower water distributor 11 to regulate the flow rate of low-temperature water entering and exiting the hot water storage tank 4. In the heat storage state, the low-temperature water at the bottom of the hot water storage tank 4 is transported outward through the lower water distributor 11, the heating network cold water pipeline 13, and the third electrically controlled regulating valve 10. In the heat release state, the low-temperature water enters the lower part of the hot water storage tank 4 under the action of the cold water pump 5 through the third electrically controlled regulating valve 10, the heating network cold water pipeline 13, and the lower water distributor 11.

[0067] The intermediate water distributor 9 is connected to one end of the extraction and discharge pipeline 14, and the other end of the extraction and discharge pipeline 14 is connected to the heating network cold water pipeline 13. The connection point between the extraction and discharge pipeline 14 and the heating network cold water pipeline 13 is located on the inlet side of the cold water pump 5, and between the third electrically controlled regulating valve 10 and the lower water distributor 11, so that when the cold water pump 5 is running, it can form a suction pressure at the outlet of the extraction and discharge pipeline 14 that is lower than the tank pressure at the height of the intermediate water distributor 9.

[0068] Along the direction of the transition mixed water flowing from the intermediate water distributor 9 to the heating network cold water pipeline 13, the pumping pipeline 14 is sequentially equipped with an anti-backflow check valve 8, a flow sensor 7, and a second electrically controlled regulating valve 6. The permissible flow direction of the anti-backflow check valve 8 is from the intermediate water distributor 9 to the heating network cold water pipeline 13, which is used to prevent water in the heating network cold water pipeline 13 from flowing back to the intermediate water distributor 9 and the hot water storage tank 4 through the pumping pipeline 14; the flow sensor 7 is used to detect the actual pumping flow rate in the pumping pipeline 14; the second electrically controlled regulating valve 6 is used to adjust the on / off state of the pumping pipeline 14 and the pumping flow rate of the transition mixed water.

[0069] When the chilled water pump 5 is running, a suction pressure is formed at the inlet side of the chilled water pump 5. When the pressure difference between the tank pressure at the height of the intermediate water distributor 9 and the pressure at the location where the pumping pipe 14 merges into the chilled water pipe 13 of the heating network is greater than the sum of the flow resistance of the pumping pipe 14 and the opening pressure difference of the anti-backflow check valve 8, the transition mixed water in the middle of the hot water storage tank 4 enters the chilled water pipe 13 of the heating network in sequence through the intermediate water distributor 9, the anti-backflow check valve 8, the flow sensor 7, and the second electrically controlled regulating valve 6, and is then transported to the heat exchange circuit of the unit by the chilled water pump 5.

[0070] Temperature sensors 12 are spaced apart along the height of the hot water storage tank 4 to detect the water temperature at different heights within the tank. The detection positions of the temperature sensors 12 at least cover the high-temperature stable zone, the active range of the thermocline, and the low-temperature stable zone, enabling the control unit to determine the upper boundary, lower boundary, center position, and thickness of the thermocline based on temperature data from different detection heights.

[0071] Hot water pump 1, first electrically controlled regulating valve 2, cold water pump 5, second electrically controlled regulating valve 6, flow sensor 7, third electrically controlled regulating valve 10, and temperature sensor 12 are respectively connected to the control unit. Temperature sensor 12 sends temperature data along the height of hot water storage tank 4 to the control unit, and flow sensor 7 sends the actual pumping flow rate to the control unit. The control unit controls the opening of the second electrically controlled regulating valve 6 according to the slope temperature layer status and the actual pumping flow rate, and coordinates the operating status of the first electrically controlled regulating valve 2, the third electrically controlled regulating valve 10, hot water pump 1, and cold water pump 5 according to the actual pumping flow rate to maintain the water balance of hot water storage tank 4. Figure 2 The diagram illustrates the connection between the intermediate water distributor 9 and the extraction / discharge assembly and the extraction / discharge pipeline 14. In an embodiment with multiple controlled extraction / discharge layers, multiple intermediate water distributors 9 are spaced apart along the height of the hot water storage tank 4, and each intermediate water distributor 9 is connected to the extraction / discharge pipeline 14 via an extraction / discharge branch equipped with a branch regulating valve. The control unit opens the branch regulating valve of the corresponding intermediate water distributor 9 according to the height range of the inclined temperature layer, and closes the branch regulating valves of the remaining intermediate water distributors 9. Multiple intermediate water distributors 9 and their extraction / discharge branches... Figure 2 Not all of them are shown in the text.

[0072] In one specific implementation, the hot water storage tank is in a heat storage state. High-temperature water enters the upper part of the hot water storage tank through high-temperature water inlet and outlet pipes and high-temperature water distribution components, while low-temperature water flows out from the lower part of the hot water storage tank through low-temperature water distribution components and low-temperature water inlet and outlet pipes. As the heat storage process continues, the high-temperature stable zone expands downward from the upper part of the hot water storage tank, and the thermocline migrates downward along the height direction of the hot water storage tank.

[0073] The temperature detection component collects water temperature data at different heights in the hot water storage tank according to a preset sampling cycle, and sends the temperature data along with the corresponding detection height to the control unit. The control unit simultaneously acquires the flow direction and flow rate in the high-temperature water inlet and outlet pipes and the low-temperature water inlet and outlet pipes, the liquid level in the hot water storage tank, the actual drainage flow rate in the drainage pipe 14, and the cold water temperature, cold water flow rate, and pipe pressure in the heating network cold water pipes.

[0074] Using the bottom of the hot water storage tank as the origin of the height coordinate system, the effective temperature data obtained by the temperature detection component are arranged from low to high according to the detection height to form a temperature sequence. The control unit determines the high-temperature stable zone based on data from multiple consecutive temperature detection locations on the upper part of the hot water storage tank, and determines the representative high-temperature temperature based on the effective temperature data within the high-temperature stable zone. The low-temperature stability zone is determined based on data from multiple consecutive temperature monitoring locations at the bottom of the hot water storage tank, and the representative low-temperature temperature is determined based on the effective temperature data within the low-temperature stability zone. .

[0075] The control unit sequentially judges the temperature at each temperature detection location from the high-temperature stable zone downwards, and when the high temperature represents the temperature... With the detection temperature When the difference between the two reaches the boundary temperature difference threshold, the height of the upper boundary of the thermocline is determined based on the temperature detection location and its adjacent temperature detection locations. Starting from the low-temperature stable zone, determine the temperature at each temperature detection location sequentially upwards. When the detection temperature... Low temperature represents temperature When the difference between the two reaches the boundary temperature difference threshold, the lower boundary height of the thermocline is determined based on the temperature detection location and its adjacent temperature detection locations. When the boundary of the thermocline is located between two adjacent temperature detection locations, the corresponding boundary height is determined by interpolation based on the temperature and height of the two adjacent temperature detection locations. Thermotropic layer thickness and central position Determine them according to the following formulas respectively:

[0076] The control unit also calculates the temperature gradient between adjacent temperature detection locations and determines whether the temperature transition zone is continuous based on the temperature gradients of multiple consecutive temperature detection locations. When a single temperature detection location exceeds the measurement range, experiences abrupt changes in adjacent cycles, or is significantly inconsistent with the adjacent detection locations above and below, the data at that temperature detection location is identified as abnormal data, and interpolation is performed based on the valid data from the adjacent detection locations above and below. When the data from multiple consecutive temperature detection locations is abnormal and the upper and lower boundaries of the slope temperature layer cannot be determined, the slope temperature layer identification result for the current control cycle is marked as invalid, and the pumping flow rate is not started or increased based on this identification result.

[0077] The control unit compares the position and thickness of the thermocline determined in multiple consecutive control cycles. The current control cycle is denoted as the [number missing]. Each control cycle, the center position and thickness of the thermocline are denoted as follows: and The rate of change of the position and thickness of the thermocline is determined based on the identification results of the current control cycle and the previous control cycle. When the center position of the thermocline gradually decreases with the control cycle, it is determined that the thermocline is moving downward; when the thickness of the thermocline gradually increases with the control cycle, it is determined that the thermocline is in a thickening trend.

[0078] In this embodiment, the downward movement of the thermocline is consistent with the expected movement direction under thermal storage conditions; therefore, pumping is not initiated separately due to the downward movement of the thermocline. When the thickness of the thermocline reaches the activation threshold corresponding to the thermal storage state, or when it is determined based on the rate of change of the thermocline thickness that the thickness will reach the activation threshold within a preset control period, the control unit determines that the current thermocline state does not meet the stratification requirements corresponding to the thermal storage state and generates a target state for the thermocline. The target state includes a thermocline thickness that is not higher than the stop threshold corresponding to the thermal storage state and the thickness no longer increasing, wherein the activation threshold is greater than the stop threshold.

[0079] The control unit is based on the current upper boundary height of the thermocline. Lower boundary height and central position From multiple controlled extraction layers spaced at intervals along the height of the hot water storage tank, the layer located at the upper boundary height is selected. and lower boundary height Between and closest to the center position The system identifies the controlled drainage layer and determines its height as the drainage position. The control unit opens the branch regulating valve connected to the selected controlled drainage layer and keeps the branch regulating valves corresponding to other controlled drainage layers closed to limit water extraction from the high-temperature stable zone and the low-temperature stable zone.

[0080] The control unit determines the thickness of the current thermocline. Target thickness corresponding to the target state of the thermocline The difference between the two values ​​determines the basic pumping flow rate. For a cross-sectional area of... For a constant cross-section hot water storage tank, the volume of the transition zone needs to be adjusted. Determined according to the following formula:

[0081] The target adjustment time is denoted as Basic pumping flow rate Determined according to the following formula:

[0082] The basic pumping flow rate is used to form the initial pumping flow rate setpoint and is not directly used as the unconstrained execution flow rate. The control unit further limits the basic pumping flow rate based on the allowable temperature rise of the heating network chilled water, the conveying capacity of the pumping pipeline 14, the allowable pumping flow rate for maintaining temperature stratification inside the tank, and the inlet and outlet water flow rates that can be compensated under thermal storage conditions.

[0083] Specifically, the flow rate and temperature of the cold water pumped into the upstream location of the heating network's cold water pipeline are respectively denoted as... and The pumping flow rate and temperature of the transition mixed water are denoted as follows: and The mixing temperature after the transition water is incorporated. Determined according to the following formula:

[0084] The control unit limits the target pumping flow rate to control the mixing temperature. The temperature shall not exceed the allowable receiving temperature of the unit's heat exchange circuit. The control unit will also compare the basic pumping flow rate with the upper limit of the flow rate corresponding to the conveying capacity of the pumping pipeline 14, the upper limit of the flow rate allowed for temperature stratification inside the tank, and the upper limit of the flow rate allowed for water balance in the hot water storage tank, and determine the minimum value among the basic pumping flow rate and each upper limit of the flow rate as the target pumping flow rate.

[0085] The connection point between the extraction pipeline 14 and the cold water pipeline of the heating network is located on the inlet side of the cold water pump 5. When the cold water pump 5 is running, a suction pressure is formed on its inlet side that is lower than the pressure at the selected controlled extraction layer in the hot water storage tank. When the difference between the pressure at the selected controlled extraction layer and the pressure on the inlet side of the cold water pump 5 is greater than the sum of the pressure loss of the extraction pipeline 14 and the opening pressure difference of the anti-backflow structure, the transition mixed water enters the extraction pipeline 14 from the controlled extraction layer under the action of the pressure difference and flows into the cold water pipeline of the heating network. In this embodiment, the suction pressure formed on the inlet side of the cold water pump 5 is used to provide the extraction driving force, and no separate extraction pump is installed.

[0086] The control unit activates the flow regulation structure based on the target pumping flow rate and adjusts the opening of the flow regulation structure based on the actual pumping flow rate detected by the flow detection structure. When the actual pumping flow rate is less than the target pumping flow rate, the opening of the flow regulation structure is increased within the upper limit of the pumping flow rate; when the actual pumping flow rate is greater than the target pumping flow rate, the opening of the flow regulation structure is decreased. If the opening of the flow regulation structure is increased but the actual pumping flow rate still cannot reach the target pumping flow rate, it is determined that the pumping drive pressure difference formed on the inlet side of the chilled water pump 5 is insufficient, and pumping stops.

[0087] During the pumping process, the influent flow rate of the high-temperature water is recorded as follows: The flow rate of the low-temperature water outlet at the bottom of the hot water storage tank is recorded as... The actual pumping flow rate is recorded as The control unit adjusts the low-temperature water outlet flow rate according to the following formula:

[0088] With the high-temperature water inlet flow rate remaining constant, the control unit reduces the low-temperature water outlet flow rate based on the actual pumping flow rate, ensuring that the low-temperature water outlet flow rate meets the following requirements:

[0089] Therefore, the amount of transition mixed water pumped out is included in the total outflow of the hot water storage tank, keeping the total inflow and outflow of the hot water storage tank balanced. When the liquid level in the hot water storage tank still deviates, the control unit further corrects the low-temperature water outflow rate based on the liquid level deviation.

[0090] At the end of each preset control evaluation cycle, the temperature detection component re-acquires the temperature distribution along the height of the hot water storage tank, and the control unit re-determines the upper boundary, lower boundary, center position, and thickness of the inclined temperature layer. The re-determination of the inclined temperature layer position and thickness after drainage uses the same inclined temperature layer identification method as before drainage, i.e., re-identifying the high-temperature stable zone, low-temperature stable zone, and temperature transition zone based on the updated temperature distribution, determining the upper and lower boundaries of the inclined temperature layer, and recalculating the position and thickness of the inclined temperature layer based on these boundaries. When the updated inclined temperature layer thickness gradually approaches the target thickness and the rate of thickness change decreases, the current controlled drainage layer is maintained, and the target drainage flow rate is gradually reduced based on the thickness deviation.

[0091] When the updated thermocline thickness does not decrease and the actual pumping flow rate is lower than the target pumping flow rate, the control unit prioritizes adjusting the opening of the flow regulation structure. When the actual pumping flow rate has reached the target pumping flow rate but the thermocline thickness still does not decrease, the target pumping flow rate is increased within the allowable range of each flow rate limit. When the selected controlled pumping layer moves downward with the thermocline and is no longer located between the upper and lower boundaries of the thermocline, the control unit closes the branch regulating valve corresponding to the current controlled pumping layer and switches to another controlled pumping layer located between the upper and lower boundaries of the updated thermocline and closest to the updated center position.

[0092] When the updated temperature gradient layer thickness continues to increase, or when pumping causes both the high-temperature and low-temperature stable zones to shrink simultaneously, the control unit determines that pumping is adversely affecting temperature stratification and reduces the target pumping flow rate. If reducing the target pumping flow rate does not improve the situation, pumping is stopped. The control unit stops pumping when the mixing temperature exceeds the allowable receiving temperature of the unit's heat exchange circuit, the hot water tank level exceeds the allowable range, the pumping drive differential pressure is insufficient, the actual pumping flow rate remains abnormal, the temperature detection data is insufficient to identify the temperature gradient layer, or the anti-backflow structure malfunctions.

[0093] When the thickness of the inclined temperature layer does not exceed the stop threshold corresponding to the thermal storage state for multiple consecutive control evaluation cycles, and the thickness of the inclined temperature layer no longer increases, it is determined that the current inclined temperature layer state continuously meets the target state. The control unit gradually reduces the target pumping flow rate, closes the flow regulation structure and the current branch regulating valve, and ends this active control of the inclined temperature layer. When the hot water storage tank switches from the thermal storage state to the heat release state, the static state, or the operating condition switching state, the control unit does not continue to use the inclined temperature layer target state corresponding to the thermal storage state, but instead redetermines the stratification requirements and the inclined temperature layer target state based on the changed operating state.

[0094] In this embodiment, the extraction location is selected based on the altitude range of the thermocline. The extraction flow rate is simultaneously constrained by thermocline state deviation, the heating network's cold water receiving capacity, pipeline transport capacity, tank disturbance, and water balance. The temperature distribution after extraction is used to provide feedback correction for the extraction location and target extraction flow rate, thus forming a closed-loop process of thermocline state identification, control target generation, controlled extraction, and control effect feedback. The above embodiment is for illustrative purposes only and does not represent the attainment of specific field operation data or quantitative results.

[0095] In summary, this embodiment has at least the following technical effects: This invention determines the upper and lower boundaries, thickness, and position of the inclined temperature layer based on the temperature distribution along the height of the hot water storage tank, and determines its movement direction and thickness change trend based on the state of the inclined temperature layer in multiple continuous control cycles. It can characterize temperature stratification from both spatial and evolutionary perspectives, avoiding the one-sidedness of identification caused by threshold judgment based solely on the thickness of a single inclined temperature layer. This invention determines the target state of the inclined temperature layer based on the stratification requirements corresponding to the states of heat storage, heat release, static placement, and operation switching. It also forms a hysteresis control by using a start threshold and a stop threshold. This allows for early initiation of regulation when the inclined temperature layer thickens rapidly, and also reduces the frequent start-up and shutdown of the pumping structure caused by fluctuations in the thickness of the inclined temperature layer near the threshold. This invention selects a controlled extraction layer based on the height range and center position of the thermocline, so that the extraction position is adjusted as the thermocline migrates, and restricts the extraction of water from the high-temperature stable zone and the low-temperature stable zone. This can reduce the disturbance of the stable temperature stratification inside the tank during the extraction process and improve the targeting of the extraction of transitional mixed water. This invention determines the basic pumping flow rate based on the deviation between the current state of the inclined temperature layer and the target state of the inclined temperature layer, and limits the basic pumping flow rate by utilizing the allowable temperature rise of the heating network cold water, the conveying capacity of the pumping pipeline 14, the allowable pumping flow rate of the temperature stratification inside the tank, and the water balance conditions. This can reduce the entrainment and stratification damage in the stable zone caused by excessive pumping flow rate, while avoiding the difficulty in achieving the expected target in the control process due to insufficient pumping flow rate. This invention, while pumping out the transitional mixed water, coordinates the inflow and outflow of water according to the operating status of the hot water storage tank and the actual pumping flow, thereby maintaining the stability of the water volume and liquid level in the hot water storage tank; by limiting the mixing temperature after the transitional mixed water enters, it can reduce the adverse effects of the rise in the cold water temperature of the heating network on the operation of the unit's heat exchange circuit. This invention connects the extraction pipeline 14 to the inlet side of the chilled water pump 5, utilizes the pressure difference formed at the inlet side of the chilled water pump 5 to transport the transition mixed water, and restricts the backflow of the heating network chilled water through the anti-backflow structure, eliminating the need for an independent extraction power source for the transition mixed water; the extracted transition mixed water enters the unit's heat exchange circuit through the heating network chilled water pipeline, and the heat it carries can continue to participate in heat exchange, reducing the heat loss caused by the direct discharge of the transition mixed water; This invention redetermines the stratified temperature layer state based on the temperature distribution after extraction, and corrects the controlled extraction layer and target extraction flow rate based on the deviation between the updated stratified temperature layer state and the target state. When the stratification state deteriorates, the transport conditions are not met, or the water balance is disrupted, the extraction flow rate is reduced or extraction is stopped, thereby forming a closed-loop control process of "state identification - target generation - controlled extraction - feedback correction", which is beneficial to restoring the effective temperature stratification and effective heat storage volume of the hot water storage tank.

[0096] It is understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A method for actively regulating the inclined temperature layer of a hot water storage tank, characterized in that, Includes the following steps: S1: Obtain operating parameters used to characterize the operating status of the hot water storage tank; S2: Determine the position and thickness of the inclined temperature layer in the current control cycle based on the temperature distribution along the height of the hot water storage tank in the operating parameters, and obtain the evolution trend of the inclined temperature layer based on the position and thickness of the inclined temperature layer in the previous multiple consecutive control cycles. S3: Determine the operating status of the hot water storage tank based on the operating parameters, and determine whether it is necessary to extract transition mixed water from the thermocline based on the operating status and the position, thickness and evolution trend of the thermocline. Furthermore, when extraction is required, the target thickness and extraction location of the inclined temperature layer are determined, the target extraction flow rate is determined based on the deviation of the current thickness of the inclined temperature layer from the target thickness, and the target extraction flow rate is limited to the range within which the hot water storage tank can maintain water balance and the water temperature after the transition mixed water flows into the cold water pipeline of the heating network does not exceed the allowable value. S4: Extract the transition mixed water from the inclined temperature layer according to the extraction location and the target extraction flow rate and transport it to the heating network cold water pipeline, and adjust the inlet and outlet water flow rates of the hot water storage tank according to the actual extraction flow rate; S5: Based on the temperature distribution after extraction, redetermine the position and thickness of the inclined temperature layer, adjust the extraction position according to the redetermined position of the inclined temperature layer, and adjust the target extraction flow rate according to the deviation of the redetermined thickness of the inclined temperature layer from the target thickness. Extraction is stopped when the redetermined thickness is not higher than the target thickness and no longer increases, or when the hot water storage tank cannot maintain water balance, or when the water temperature of the cold water pipeline of the heating network exceeds the allowable value.

2. The method for active regulation of the inclined temperature layer in a hot water storage tank according to claim 1, characterized in that, The determination of the position and thickness of the inclined temperature layer includes: identifying a high-temperature stable region, a low-temperature stable region, and a temperature transition region between them based on the temperature change with the detection height in the temperature distribution; determining the boundary between the temperature transition region and the high-temperature stable region and the low-temperature stable region as the upper boundary and the lower boundary, respectively; determining the intermediate height between the upper boundary and the lower boundary as the position of the inclined temperature layer; and determining the height difference between the upper boundary and the lower boundary as the thickness of the inclined temperature layer.

3. The method for active regulation of the inclined temperature layer in a hot water storage tank according to claim 1, characterized in that, The determination of the evolution trend includes: comparing the position and thickness of the thermocline in multiple consecutive control cycles, determining the movement direction of the thermocline based on the change in position, and determining a thickening trend, a thinning trend, or a stable trend based on the change in thickness.

4. The method for active regulation of the inclined temperature layer in a hot water storage tank according to claim 1, characterized in that, The operating states include heat storage state, heat release state, static state, and operating condition switching state. Each operating state has a start threshold and a stop threshold, and the start threshold corresponding to the same operating state is greater than the stop threshold. When the thickness of the thermocline reaches the start threshold corresponding to the current operating state, or when it is determined from the evolution trend that the thickness of the thermocline will reach the start threshold within a preset time, it is determined that the transition mixed water needs to be extracted, and the stop threshold corresponding to the operating state is determined as the target thickness.

5. The method for active regulation of the inclined temperature layer in a hot water storage tank according to claim 1, characterized in that, The determination of the extraction position includes: selecting, from a plurality of extraction layers spaced apart along the height direction of the hot water storage tank, the extraction layer located within the height range of the inclined temperature layer and whose height is closest to the position, and determining the height of the selected extraction layer as the extraction position; when the inclined temperature layer moves so that the selected extraction layer is no longer within the height range of the inclined temperature layer, the extraction layer is reselected according to the updated position of the inclined temperature layer.

6. The method for active regulation of the inclined temperature layer in a hot water storage tank according to claim 1, characterized in that, The determination of the target drainage flow rate includes: determining the basic drainage flow rate based on the difference between the thickness and the target thickness and the target adjustment time; limiting the basic drainage flow rate based on the allowable temperature rise of the heating network cold water pipeline, the conveying capacity of the drainage pipeline, the temperature stratification requirements inside the tank and the inlet and outlet water regulation capacity of the hot water storage tank; and determining the limited basic drainage flow rate as the target drainage flow rate.

7. The method for actively regulating the inclined temperature layer of a hot water storage tank according to any one of claims 1 to 6, characterized in that, The adjustment of the extraction position and the target extraction flow rate includes: redetermining the position and thickness of the inclined temperature layer according to a preset control evaluation cycle; adjusting the extraction position according to the redetermined position; and adjusting the target extraction flow rate according to the deviation of the redetermined thickness from the target thickness. When the thickness is not higher than the target thickness and no longer increases, or the actual extraction flow rate continues to deviate from the target extraction flow rate and exceeds the allowable range, or the liquid level of the hot water storage tank exceeds the allowable range, the extraction is stopped.

8. A hot water storage tank inclined temperature layer active control system, characterized in that, include: Hot water storage tanks are used to contain hot water and create temperature stratification. A high-temperature water distribution component is installed on the upper part of the hot water storage tank and connected to the high-temperature water inlet and outlet pipelines; A low-temperature water distribution assembly is installed at the bottom of the hot water storage tank and connected to the low-temperature water inlet and outlet pipelines; A temperature detection component is installed along the height of the hot water storage tank to detect the water temperature at different heights; The middle layer extraction assembly is located within the active height range of the inclined temperature layer and has multiple extraction layers spaced apart along the height direction of the hot water storage tank, for extracting the transition mixed water in the inclined temperature layer; The extraction pipeline is connected between the middle layer extraction assembly and the cold water pipeline of the heating network. The extraction pipeline is equipped with a flow regulating valve and a flow sensor for detecting the actual extraction flow. The inlet and outlet water regulating component is connected to the high-temperature water inlet and outlet pipeline and the low-temperature water inlet and outlet pipeline respectively, and is used to regulate the inlet and outlet water flow of the hot water storage tank. The low-temperature water inlet and outlet pipeline is connected to the heating network cold water pipeline. The inlet and outlet water regulating component includes a cold water pump installed in the heating network cold water pipeline, and the pumping pipeline is connected to the inlet side of the cold water pump. as well as The control unit is connected to the temperature detection component, the middle layer pumping component, the flow regulating valve, the flow sensor, and the inlet / outlet water regulating component, respectively. It is used to determine the operating status of the hot water storage tank and the position, thickness, and evolution trend of the inclined temperature layer based on the water temperature at different heights and the working status of the inlet / outlet water regulating component. When pumping is required, it determines the target thickness, selects the pumping layer, and determines the target pumping flow rate. It controls the middle layer pumping component to pump the transition mixed water and adjusts the inlet / outlet water flow rate according to the actual pumping flow rate. It also adjusts the selected pumping layer and the target pumping flow rate according to the temperature distribution after pumping.

9. The active temperature control system for the inclined temperature layer of a hot water storage tank according to claim 8, characterized in that, The middle-layer extraction assembly includes a plurality of annular extraction pipes spaced apart along the height direction of the hot water storage tank. Each annular extraction pipe constitutes an extraction layer and is provided with a plurality of extraction holes spaced apart circumferentially. Each annular extraction pipe is connected to the extraction pipeline through an extraction branch with a branch regulating valve, and the branch regulating valve is connected to the control unit.

10. The active temperature control system for the inclined temperature layer of a hot water storage tank according to claim 8, characterized in that, The pumping pipeline is also equipped with a one-way valve, which allows the transition mixed water to flow to the heating network cold water pipeline and prevents reverse flow. The control unit adjusts the flow regulating valve according to the deviation between the actual pumping flow rate and the target pumping flow rate.

Images