Circulating water heating control system and method based on waste heat of reclaimed water

Abstract

The invention relates to the technical field of circulating water heating control, and discloses a circulating water heating control system and method based on recycled water waste heat. The entropy calculation module calculates an available waste heat entropy based on the temperature parameter sequence and the flow parameter sequence; the quality generation module inquires a water quality thermal resistance mapping table according to the reclaimed water source type identifier, and generates a waste heat quality grading index; the demand calculation module calculates a circulating water thermal load demand index according to the difference value between the return water temperature and the water supply target temperature; the fusion analysis module fuses the waste heat quality grading index and the available waste heat entropy value to generate a reclaimed water side heat supply capacity index, and calculates a power distribution reference parameter; and the heating control module determines a valve opening adjusting instruction and a power set value of auxiliary heating equipment and generates a circulating water heating control instruction set, so that the utilization rate of recycled water is maximized while the heat supply quality is ensured, and the energy efficiency and the operation stability of the system are improved.

Description

Technical Field

[0001] This invention relates to the field of circulating water heating control technology, and more specifically, to a circulating water heating control system and method based on waste heat from reclaimed water. Background Technology

[0002] Waste heat utilization of reclaimed water refers to the energy-saving technology of extracting low-temperature heat energy from the reclaimed water discharged from urban sewage treatment plants for building heating or process heating. It is an important way to realize the energy utilization of urban sewage and carbon emission reduction.

[0003] Existing waste heat recovery systems for reclaimed water mainly employ simple control methods based on constant flow rate or constant temperature difference. They rely on experience to set fixed valve openings on the reclaimed water side and maintain circulating water temperature by controlling the start and stop of auxiliary heat sources. However, current technologies struggle to assess the impact of fluctuations in reclaimed water waste heat quality and differences in water quality on heat exchange efficiency. They cannot dynamically allocate the ratio of reclaimed water waste heat to auxiliary heat sources according to heat load demands, and they lack the ability to predict changes in reclaimed water flow rate. Furthermore, when the reclaimed water temperature drops sharply or the flow rate is interrupted, the system cannot switch to standby mode in a timely manner, leading to uncontrolled circulating water temperature and hindering safe, efficient, and stable coordinated operation. Summary of the Invention

[0004] To address the aforementioned technical problems, the purpose of this application is to provide a circulating water heating control system and method based on waste heat from reclaimed water. By calculating the waste heat quality grading index and the heat load demand index, the system achieves thermodynamic matching and optimized allocation between waste heat from reclaimed water and auxiliary heat sources. Combined with feedback closed-loop and feedforward predictive control, the system maximizes the utilization rate of reclaimed water while ensuring heating quality, thereby improving the energy efficiency and operational stability of the system.

[0005] To achieve the above objectives, the present invention provides a circulating water heating control system based on waste heat from reclaimed water, comprising: The data acquisition module is used to acquire the temperature parameter sequence and flow parameter sequence of the reclaimed water supply system, and simultaneously acquire the return water temperature, target water supply temperature and pipeline circulation flow of the circulating water system, as well as the ambient temperature and reclaimed water source type identifier. The entropy calculation module is used to calculate the available waste heat entropy value of the reclaimed water based on the temperature parameter sequence and the flow parameter sequence. The available waste heat entropy value represents the total amount of usable heat energy carried by the reclaimed water. The quality generation module is used to query a preset water quality thermal resistance mapping table based on the reclaimed water source type identifier, and generate a waste heat quality grading index by combining the stability characteristics of the temperature parameter sequence. The demand calculation module is used to calculate the circulating water heat load demand index based on the difference between the return water temperature and the target supply water temperature, combined with the pipeline circulation flow rate and pipeline heat loss characteristic parameters. The circulating water heat load demand index represents the amount of heat energy supplement required to maintain the target temperature. The fusion analysis module is used to fuse the waste heat quality classification index with the available waste heat entropy value to generate the reclaimed water side heating capacity index, and to calculate the thermodynamic matching degree between the heating capacity index and the circulating water heat load demand index to generate power allocation benchmark parameters. The heating control module is used to respond to the power distribution reference parameters, determine the valve opening adjustment command of the reclaimed water heat exchange branch and the power setting value of the auxiliary heating equipment, and generate a set of circulating water heating control commands. The set of control commands is used to coordinate the collaborative operation of reclaimed water waste heat utilization and auxiliary heat source.

[0006] Furthermore, the quality generation module is used for: The temperature parameter sequence is subjected to a sliding window standard deviation calculation, with the window length set to 5 to 10 sampling periods, to generate a temperature fluctuation index; Based on the comparison result between the temperature fluctuation index and the preset stability threshold, a temperature stability coefficient is generated. When the temperature fluctuation index is less than the preset stability threshold, the temperature stability coefficient is 1. When the temperature fluctuation index is greater than or equal to the preset stability threshold, the temperature stability coefficient is the ratio of the preset stability threshold to the temperature fluctuation index. Based on the reclaimed water source type identifier, distinguish between industrial cooling water, domestic sewage, or process condensate, and look up the corresponding thermal resistance coefficient; The waste heat quality grading index is generated by taking a weighted geometric average of the temperature stability coefficient and the thermal resistance coefficient.

[0007] Furthermore, the demand calculation module is used for: Calculate the absolute value of the difference between the target supply water temperature and the return water temperature to obtain the instantaneous temperature rise requirement, and calculate the instantaneous heat load based on the pipeline circulation flow rate and the specific heat capacity of water. Based on the thermal conductivity of the insulation layer, the outer diameter and length of the pipeline, and the ambient temperature, the friction loss rate of the pipeline is calculated. Obtain the current ambient temperature and the typical design temperature of the area where the circulating water pipe network is located, and calculate the ambient temperature difference adjustment coefficient; The circulating water heat load demand index is generated by integrating the instantaneous heat load, the heat loss rate along the pipeline, and the ambient temperature difference adjustment coefficient.

[0008] Furthermore, the fusion analysis module is used for: The ratio of the available waste heat entropy value to the circulating water heat load demand index is calculated to obtain the supply-demand ratio. The supply-demand ratio is then limited. When the supply-demand ratio is greater than 1, the value is 1. When the supply-demand ratio is less than 0, the value is 0. When the supply-demand ratio is between 0 and 1, the original value is maintained. Obtain the logarithmic mean temperature difference and heat transfer coefficient of the reclaimed water heat exchanger, calculate the maximum theoretical heat transfer of the heat exchanger, compare the maximum theoretical heat transfer with the available waste heat entropy value, and generate a heat exchange efficiency constraint coefficient. The heat exchange efficiency constraint coefficient is the minimum value between the ratio of the two and 1. Based on the degree of deviation between the current ambient temperature and the standard operating temperature, a climate regulation factor is generated; The supply-demand ratio, heat exchange efficiency constraint coefficient, and climate regulation factor are weighted and fused to generate power allocation benchmark parameters.

[0009] Furthermore, the fusion analysis module is used for: Obtain the current opening position of the regulating valve in the reclaimed water heat exchange branch and the valve flow characteristic curve, wherein the flow characteristic curve includes linear characteristic, equal percentage characteristic or fast opening characteristic; The product of the power allocation reference parameter and the circulating water heat load demand index is used as the target heat load to be borne by the reclaimed water side. Based on the target heat load, specific heat capacity of reclaimed water and inlet / outlet temperature difference in the temperature parameter sequence, calculate the required reclaimed water flow rate adjustment; Based on the valve flow characteristic curve, the reclaimed water flow rate adjustment is mapped to the theoretical valve opening. The difference between the theoretical valve opening and the current opening position is calculated to generate the opening adjustment increment, which is limited by the valve's maximum allowable adjustment rate, and the final opening adjustment command is generated.

[0010] Furthermore, the heating control module is used for: Determine the maximum effective heat exchange threshold of the reclaimed water heat exchange branch, wherein the maximum effective heat exchange threshold is set by the reclaimed water flow rate and the minimum allowable discharge temperature of the reclaimed water. The circulating water heat load demand index is compared with the maximum effective heat exchange threshold. When the circulating water heat load demand index is less than or equal to the maximum effective heat exchange threshold, the power setting value of the auxiliary heating equipment is set to zero. When the circulating water heat load demand index is greater than the maximum effective heat exchange threshold, the difference between the circulating water heat load demand index and the maximum effective heat exchange threshold is used to obtain the auxiliary heat load gap. Based on the real-time efficiency curve of the auxiliary heating equipment, the optimal operating power point corresponding to the auxiliary heat load gap is queried. The optimal operating power point is the minimum power value on the efficiency curve that is closest to the auxiliary heat load gap and not less than the auxiliary heat load gap. The optimal operating power point is used as the power setting value.

[0011] Furthermore, it also includes: Instruction optimization module, used for: Obtain the reclaimed water flow scheduling plan and the heat load forecast curve of the circulating water system for future time periods; Based on the statistical characteristics of the reclaimed water flow scheduling plan and historical temperature parameter sequences, the prospective available waste heat entropy value is calculated using the moving average method. Based on the aforementioned heat load forecast curve and pipeline heat loss characteristic parameters, the forward heat load demand index is calculated. Based on the matching relationship between the prospective available waste heat entropy value and the prospective heat load demand index, a feedforward control command sequence is generated; Calculate the time interval between the current moment and the corresponding moment in the feedforward control command sequence, and generate a time decay weight, wherein the time decay weight decays exponentially with the time interval; The feedforward control command sequence is weighted and fused with the current control command according to the time decay weight to generate the optimized control command.

[0012] Furthermore, it also includes: The anomaly detection module is used to determine whether the waste heat source of reclaimed water is abnormal.

[0013] Furthermore, the anomaly detection module is used for: The temperature parameter sequence of the reclaimed water supply system is continuously monitored. When the temperature value of multiple consecutive sampling cycles is lower than the minimum usable temperature threshold of reclaimed water, it is determined to be an abnormal condition of the waste heat source of reclaimed water. In response to the abnormal operating condition of the waste heat source, the standby heating mode is triggered, the opening adjustment command is forcibly set to zero, and the reclaimed water heat exchange branch is shut down. Increase the power setting of the auxiliary heating equipment to meet the calculated value of the circulating water heat load demand index; An alarm signal for an abnormal waste heat source is generated, and a timer is started. When the duration of the abnormality exceeds the preset switching delay, the control mode is permanently switched to pure auxiliary heating mode until a manual reset command is received.

[0014] To achieve the above objectives, the present invention also provides a circulating water heating control method based on waste heat from reclaimed water, comprising: Acquire the temperature and flow parameter sequences of the reclaimed water supply system, simultaneously collect the return water temperature, target supply temperature, and pipeline circulation flow of the circulating water system, and collect the ambient temperature and reclaimed water source type identifier. The available waste heat entropy value of the reclaimed water is calculated based on the temperature parameter sequence and the flow rate parameter sequence. The available waste heat entropy value represents the total amount of usable heat energy carried by the reclaimed water. Based on the reclaimed water source type identifier, a preset water quality thermal resistance mapping table is queried, and combined with the stability characteristics of the temperature parameter sequence, a waste heat quality grading index is generated. Based on the difference between the return water temperature and the target supply water temperature, and combined with the pipeline circulation flow rate and pipeline heat loss characteristic parameters, the circulating water heat load demand index is calculated. The circulating water heat load demand index represents the amount of heat energy required to maintain the target temperature. The waste heat quality classification index is fused with the available waste heat entropy value to generate a reclaimed water side heating capacity index. The heating capacity index is then thermodynamically matched with the circulating water heat load demand index to generate power allocation benchmark parameters. In response to the power allocation reference parameters, the valve opening adjustment command of the reclaimed water heat exchange branch and the power setting value of the auxiliary heating equipment are determined, and a circulating water heating control command set is generated. The control command set is used to coordinate the collaborative operation of reclaimed water waste heat utilization and auxiliary heat source.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention discloses a circulating water heating control system and method based on waste heat from reclaimed water. A data acquisition module obtains temperature and flow data from the reclaimed water supply system; an entropy calculation module calculates the available waste heat entropy based on temperature and flow parameter sequences; a quality generation module queries a water quality thermal resistance mapping table based on the reclaimed water source type identifier to generate a waste heat quality grading index; a demand calculation module calculates the circulating water heat load demand index based on the difference between the return water temperature and the target supply water temperature; a fusion analysis module merges the waste heat quality grading index and the available waste heat entropy to generate a reclaimed water-side heating capacity index and calculates power allocation benchmark parameters; and a heating control module determines valve opening adjustment commands and auxiliary heating equipment power setpoints to generate a circulating water heating control command set, ensuring heating quality while maximizing reclaimed water utilization and improving system energy efficiency and operational stability. Attached Figure Description

[0016] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 A schematic diagram of the circulating water heating control system based on waste heat from reclaimed water is shown in an embodiment of the present invention. Figure 2 A schematic flowchart of a circulating water heating control method based on waste heat from reclaimed water is shown in an embodiment of the present invention. Detailed Implementation

[0017] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0018] In the description of this application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0019] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0020] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0021] The following is a description of preferred embodiments of the present invention in conjunction with the accompanying drawings.

[0022] like Figure 1 As shown, embodiments of the present invention disclose a circulating water heating control system based on waste heat from reclaimed water, comprising: The data acquisition module is used to acquire the temperature parameter sequence and flow parameter sequence of the reclaimed water supply system, and simultaneously acquire the return water temperature, target water supply temperature and pipeline circulation flow of the circulating water system, as well as the ambient temperature and reclaimed water source type identifier. The entropy calculation module is used to calculate the available waste heat entropy value of the reclaimed water based on the temperature parameter sequence and the flow parameter sequence. The available waste heat entropy value represents the total amount of usable heat energy carried by the reclaimed water. The quality generation module is used to query a preset water quality thermal resistance mapping table based on the reclaimed water source type identifier, and generate a waste heat quality grading index by combining the stability characteristics of the temperature parameter sequence. The demand calculation module is used to calculate the circulating water heat load demand index based on the difference between the return water temperature and the target supply water temperature, combined with the pipeline circulation flow rate and pipeline heat loss characteristic parameters. The circulating water heat load demand index represents the amount of heat energy supplement required to maintain the target temperature. The fusion analysis module is used to fuse the waste heat quality classification index with the available waste heat entropy value to generate the reclaimed water side heating capacity index, and to calculate the thermodynamic matching degree between the heating capacity index and the circulating water heat load demand index to generate power allocation benchmark parameters. The heating control module is used to respond to the power distribution reference parameters, determine the valve opening adjustment command of the reclaimed water heat exchange branch and the power setting value of the auxiliary heating equipment, and generate a set of circulating water heating control commands. The set of control commands is used to coordinate the collaborative operation of reclaimed water waste heat utilization and auxiliary heat source.

[0023] In this embodiment, the reclaimed water supply system refers to the reclaimed water reuse network after secondary treatment at the municipal wastewater treatment plant. Temperature parameter sequences are collected by temperature sensors installed at the reclaimed water inlet and outlet, with a sampling period of 1 minute, and recorded as time-series data. Flow parameter sequences are obtained through electromagnetic flow meters, with units of cubic meters per hour. The circulating water system refers to the building heating or process cooling water system. The return water temperature refers to the temperature returned after heat dissipation at the terminal, and the target supply temperature refers to the setpoint to be maintained (e.g., 45°C). The network circulation flow rate is obtained through feedback from the circulating water pump speed or a flow meter. Ambient temperature is obtained through an outdoor weather station or building exterior wall temperature sensors. The reclaimed water source type identifier is used to distinguish between industrial cooling water, domestic sewage, or process condensate, as different sources have different water quality characteristics. The usable waste heat entropy value is obtained by calculating the product of the reclaimed water flow rate, specific heat capacity, and inlet / outlet temperature difference, characterizing the total amount of heat energy recoverable per unit time.

[0024] In some embodiments of this application, the quality generation module is used for: The temperature parameter sequence is subjected to a sliding window standard deviation calculation, with the window length set to 5 to 10 sampling periods, to generate a temperature fluctuation index; Based on the comparison result between the temperature fluctuation index and the preset stability threshold, a temperature stability coefficient is generated. When the temperature fluctuation index is less than the preset stability threshold, the temperature stability coefficient is 1. When the temperature fluctuation index is greater than or equal to the preset stability threshold, the temperature stability coefficient is the ratio of the preset stability threshold to the temperature fluctuation index. Based on the reclaimed water source type identifier, distinguish between industrial cooling water, domestic sewage, or process condensate, and look up the corresponding thermal resistance coefficient; The waste heat quality grading index is generated by taking a weighted geometric average of the temperature stability coefficient and the thermal resistance coefficient.

[0025] In this embodiment, the sliding window standard deviation calculation refers to taking temperature data from the most recent 5 to 10 sampling times (i.e., 5 to 10 minutes) and calculating the statistical standard deviation of these data. The larger the standard deviation, the more drastic the temperature fluctuation and the less stable the waste heat quality. The preset stability threshold is set based on the historical operating data of the reclaimed water system. For example, if it is set to 2℃, when the standard deviation is less than 2℃, the temperature is considered stable, and the temperature stability coefficient is 1.0; when the standard deviation is 4℃, the stability coefficient is 0.5. The thermal resistance coefficient is obtained by querying a preset mapping table. Industrial cooling water has a lower salt content and turbidity, so the thermal resistance coefficient is set to 0.0003 square Kelvin per watt; domestic sewage contains more organic matter and suspended solids, so the thermal resistance coefficient is set to 0.0005 square Kelvin per watt; process condensate has the best water quality, so the thermal resistance coefficient is set to 0.0001 square Kelvin per watt. The weighted geometric mean is calculated as follows: Waste heat quality grading index = temperature stability coefficient to the power of 0.6 multiplied by the reciprocal of thermal resistance coefficient to the power of 0.4, then divided by the normalization factor to ensure the result is between 0 and 1. The closer the index is to 1, the better the waste heat quality of the reclaimed water (stable temperature and clean water quality), and the closer it is to 0, the worse the quality (large temperature fluctuations or easy scaling).

[0026] The beneficial effects of the above technical solution are: real-time monitoring of reclaimed water temperature stability through sliding window standard deviation, introduction of the influence of water quality on heat exchange performance through water quality thermal resistance mapping table, and comprehensive evaluation of waste heat quality through weighted geometric average, providing a scientific basis for subsequent power allocation and avoiding the problem of heat exchange efficiency decline caused by water quality deterioration or temperature fluctuation.

[0027] In some embodiments of this application, the demand calculation module is used for: Calculate the absolute value of the difference between the target supply water temperature and the return water temperature to obtain the instantaneous temperature rise requirement, and calculate the instantaneous heat load based on the pipeline circulation flow rate and the specific heat capacity of water. Based on the thermal conductivity of the insulation layer, the outer diameter and length of the pipeline, and the ambient temperature, the friction loss rate of the pipeline is calculated. Obtain the current ambient temperature and the typical design temperature of the area where the circulating water pipe network is located, and calculate the ambient temperature difference adjustment coefficient; The circulating water heat load demand index is generated by integrating the instantaneous heat load, the heat loss rate along the pipeline, and the ambient temperature difference adjustment coefficient.

[0028] In this embodiment, the instantaneous heat load is calculated by multiplying the circulation flow rate (e.g., 100 cubic meters per hour) by the specific heat capacity of water (4.2 kJ / kg Kelvin) by the temperature rise requirement (5°C), and then dividing by the time conversion factor of 3.6 to obtain 583 kW. The characteristic parameters of the pipeline heat loss include the thermal conductivity of the insulation layer (e.g., 0.03 W / m Kelvin for polyurethane foam), the outer diameter of the pipe (e.g., 0.2 m), and the length of the pipeline (e.g., 500 m). The heat loss rate is calculated using the cylindrical wall heat conduction formula, combined with the temperature difference between the ambient temperature (e.g., -5°C) and the water temperature inside the pipe (average 42.5°C) to obtain the heat loss per unit pipe length, which is then multiplied by the total length to obtain the total heat loss power (e.g., 50 kW). Typical design temperatures are determined based on local meteorological parameters; for example, the typical design temperature for heating areas in northern China is -10℃. The environmental temperature difference adjustment coefficient is calculated by multiplying the absolute value of the difference between the current ambient temperature (-5℃) and the design temperature (-10℃) (5℃) by the adjustment coefficient (e.g., 10 kW per degree Celsius), resulting in an adjustment of 50 kW. The circulating water heat load demand index is calculated by adding the immediate heat load (583 kW) to the network heat loss (50 kW) and the environmental temperature difference adjustment (50 kW), totaling 683 kW, representing the total amount of heat energy required to maintain the target temperature.

[0029] The beneficial effects of the above technical solution are as follows: by calculating the instantaneous heat load, pipeline heat loss and ambient temperature difference adjustment respectively, the various heat demands of the circulating water system are fully considered; by introducing pipeline heat loss characteristic parameters, the energy loss during long-distance transportation is quantified; and by adjusting the ambient temperature difference, the impact of outdoor temperature changes on the heat load is adapted, making the heat load calculation more accurate and avoiding insufficient heating due to underestimation or energy waste due to overestimation.

[0030] In some embodiments of this application, the fusion analysis module is used for: The ratio of the available waste heat entropy value to the circulating water heat load demand index is calculated to obtain the supply-demand ratio. The supply-demand ratio is then limited. When the supply-demand ratio is greater than 1, the value is 1. When the supply-demand ratio is less than 0, the value is 0. When the supply-demand ratio is between 0 and 1, the original value is maintained. Obtain the logarithmic mean temperature difference and heat transfer coefficient of the reclaimed water heat exchanger, calculate the maximum theoretical heat transfer of the heat exchanger, compare the maximum theoretical heat transfer with the available waste heat entropy value, and generate a heat exchange efficiency constraint coefficient. The heat exchange efficiency constraint coefficient is the minimum value between the ratio of the two and 1. Based on the degree of deviation between the current ambient temperature and the standard operating temperature, a climate regulation factor is generated; The supply-demand ratio, heat exchange efficiency constraint coefficient, and climate regulation factor are weighted and fused to generate power allocation benchmark parameters.

[0031] In this embodiment, the available waste heat entropy value is multiplied by the waste heat quality grading index to obtain the reclaimed water side heating capacity index. The supply-demand ratio is calculated by dividing the available waste heat entropy value (e.g., 800 kW) by the heat load demand index (e.g., 683 kW), resulting in 1.17. After limiting processing, it is taken as 1.0, indicating that the reclaimed water waste heat is sufficient. Limiting processing (also known as limiting, clipping, or saturation processing) refers to a data processing method that forcibly restricts the value within a preset upper and lower limit range. For example: if the value is too high (exceeding the upper limit) → it is forcibly reduced to the upper limit value; if the value is too low (below the lower limit) → it is forcibly increased to the lower limit value; if the value is within the range → it remains unchanged. The logarithmic mean temperature difference is calculated based on the inlet and outlet temperatures of reclaimed water (e.g., 20℃ inlet, 15℃ outlet) and the inlet and outlet temperatures of circulating water (e.g., 40℃ inlet, 45℃ outlet), and is approximately 9.8 Kelvin; the heat transfer coefficient is set according to the heat exchanger model and scaling conditions, such as 3000 watts per square meter of Kelvin; the maximum theoretical heat transfer is the heat transfer coefficient multiplied by the heat exchange area (e.g., 50 square meters) multiplied by the logarithmic mean temperature difference, and is approximately 1470 kilowatts; the heat exchange efficiency constraint coefficient is the smaller value of 1470 and 800, 800 divided by the available waste heat entropy value 800, resulting in 1.0, indicating that the heat exchanger capacity is sufficient. The standard operating temperature is set at 20℃, the current ambient temperature is -5℃, and the deviation is 25℃; the climate adjustment factor is calculated by multiplying the arithmetic square root of the deviation (5) by the proportional coefficient (e.g., 0.02), resulting in 0.1, which characterizes the impact of cold weather on heat exchange efficiency. When weighted, the supply-demand ratio has a weight of 40%, the heat exchange efficiency constraint coefficient has a weight of 40%, and the climate regulation factor has a weight of 20%. The power allocation benchmark parameter is calculated by multiplying the supply-demand ratio and the constraint coefficient and then dividing by the square root of the climate regulation factor. After normalization, it is 0.95, which means that the reclaimed water should bear 95% of the heat load.

[0032] The beneficial effects of the above technical solution are: the heat transfer capacity limitation of the heat exchanger itself is considered by the heat exchange efficiency constraint coefficient; the nonlinear influence of ambient temperature on heat exchange performance is introduced by the climate adjustment factor; and the power allocation benchmark parameters that comprehensively consider the sufficiency of heat source, equipment capacity and climate conditions are generated by weighted fusion, so as to realize the priority utilization of waste heat from reclaimed water and the precise supplementation of auxiliary heat source.

[0033] In some embodiments of this application, the fusion analysis module is used for: Obtain the current opening position of the regulating valve in the reclaimed water heat exchange branch and the valve flow characteristic curve, wherein the flow characteristic curve includes linear characteristic, equal percentage characteristic or fast opening characteristic; The product of the power allocation reference parameter and the circulating water heat load demand index is used as the target heat load to be borne by the reclaimed water side. Based on the target heat load, specific heat capacity of reclaimed water and inlet / outlet temperature difference in the temperature parameter sequence, calculate the required reclaimed water flow rate adjustment; Based on the valve flow characteristic curve, the reclaimed water flow rate adjustment is mapped to the theoretical valve opening. The difference between the theoretical valve opening and the current opening position is calculated to generate the opening adjustment increment, which is limited by the valve's maximum allowable adjustment rate, and the final opening adjustment command is generated.

[0034] In this embodiment, the current opening position of the regulating valve is obtained through feedback from the valve positioner, such as a current opening of 50%. The flow characteristic curve is determined according to the valve model. The equal percentage characteristic means that for every 1% increase in opening, the flow rate increases exponentially, which is suitable for precise adjustment. The required reclaimed water flow rate is calculated by multiplying the target heat load (649 kW) by 3.6, dividing by the specific heat capacity (4.2 kJ / kg Kelvin), and dividing by the inlet and outlet temperature difference (5°C), resulting in approximately 111 cubic meters per hour. According to the equal percentage characteristic curve, if the current flow rate is 80 cubic meters per hour, the corresponding opening is 50%, and the target flow rate is 111 cubic meters per hour, the corresponding opening is 65%. Therefore, the theoretical valve opening is 65%. The opening adjustment increment is 65% minus 50%, which equals 15%. This is limited by the valve's maximum allowable adjustment rate (e.g., 10% per minute). If the calculation cycle is 1 minute, the actual adjustment increment is 10%, and the final opening command is 60%. The next cycle continues to adjust to 65% to avoid hydraulic shock.

[0035] The beneficial effects of the above technical solution are as follows: by introducing the valve flow characteristic curve, a precise correspondence between opening degree and flow rate is established; the target load on the reclaimed water side is determined by multiplying the power distribution reference parameter and the heat load demand index, realizing on-demand adjustment; the pipeline system is protected by limiting the adjustment rate, avoiding water hammer or pressure fluctuations caused by sudden flow changes, and achieving smooth and stable flow control.

[0036] In some embodiments of this application, the heating control module is used for: Determine the maximum effective heat exchange threshold of the reclaimed water heat exchange branch, wherein the maximum effective heat exchange threshold is set by the reclaimed water flow rate and the minimum allowable discharge temperature of the reclaimed water. The circulating water heat load demand index is compared with the maximum effective heat exchange threshold. When the circulating water heat load demand index is less than or equal to the maximum effective heat exchange threshold, the power setting value of the auxiliary heating equipment is set to zero. When the circulating water heat load demand index is greater than the maximum effective heat exchange threshold, the difference between the circulating water heat load demand index and the maximum effective heat exchange threshold is used to obtain the auxiliary heat load gap. Based on the real-time efficiency curve of the auxiliary heating equipment, the optimal operating power point corresponding to the auxiliary heat load gap is queried. The optimal operating power point is the minimum power value on the efficiency curve that is closest to the auxiliary heat load gap and not less than the auxiliary heat load gap. The optimal operating power point is used as the power setting value.

[0037] In this embodiment, the minimum allowable discharge temperature of reclaimed water refers to the temperature limit (e.g., 10°C) that the reclaimed water must not fall below after heat exchange, to protect downstream reuse processes or prevent pipeline freezing. The maximum effective heat exchange threshold is calculated by multiplying the reclaimed water flow rate (e.g., 200 cubic meters per hour) by the specific heat capacity (4.2 kJ / kg Kelvin), multiplying the temperature difference (10°C) between the inlet temperature (20°C) and the minimum allowable discharge temperature (10°C), and then dividing by 3.6 to obtain 2333 kW, representing the theoretically maximum recoverable heat. That is, (200 4.2 10) / 3.6. When the circulating water heat load demand index is 683 kW (less than 2333 kW), the auxiliary heating equipment power is set to 0, and the load is entirely borne by reclaimed water; when the demand index is 3000 kW (greater than 2333 kW), the auxiliary heat load gap is 3000 minus 2333 equals 667 kW. The real-time efficiency curve of the auxiliary heating equipment (such as a gas boiler) records the thermal efficiency at different load rates, such as 85% efficiency at 30% load rate, 90% efficiency at 50% load rate, and 88% efficiency at 80% load rate; the optimal operating power point is selected from the power range closest to and not less than 667 kW. For example, if the boiler rated power is 1000 kW, then a 70% load rate of 700 kW is selected, which satisfies the demand gap while ensuring high efficiency.

[0038] The beneficial effects of the above technical solution are as follows: the utilization boundary of waste heat of reclaimed water is clarified by the maximum effective heat exchange threshold, avoiding excessive extraction that leads to excessively low reclaimed water temperature; the auxiliary heat source can be started and stopped on demand by comparing with the demand index; and the auxiliary heat source is ensured to operate in the high-efficiency range by querying the real-time efficiency curve, avoiding low-load low-efficiency or high-load overload operation, thus improving the overall energy efficiency of the system.

[0039] In some embodiments of this application, it also includes: Instruction optimization module, used for: Obtain the reclaimed water flow scheduling plan and the heat load forecast curve of the circulating water system for future time periods; Based on the statistical characteristics of the reclaimed water flow scheduling plan and historical temperature parameter sequences, the prospective available waste heat entropy value is calculated using the moving average method. Based on the aforementioned heat load forecast curve and pipeline heat loss characteristic parameters, the forward heat load demand index is calculated. Based on the matching relationship between the prospective available waste heat entropy value and the prospective heat load demand index, a feedforward control command sequence is generated; Calculate the time interval between the current moment and the corresponding moment in the feedforward control command sequence, and generate a time decay weight, wherein the time decay weight decays exponentially with the time interval; The feedforward control command sequence is weighted and fused with the current control command according to the time decay weight to generate the optimized control command.

[0040] In this embodiment, the duration of the future time period is set to 30 minutes to 2 hours. The reclaimed water flow scheduling plan comes from the wastewater treatment plant's scheduling plan or the usage plan of upstream users, such as the flow rate increasing from 200 cubic meters per hour to 300 cubic meters per hour in the next hour. The heat load forecast curve is generated based on weather forecasts and building thermal inertia models, such as the predicted heat load increasing from 683 kW to 800 kW in the next 30 minutes. The forward-looking waste heat entropy value can be calculated based on the flow rate of the scheduling plan and the historical average temperature difference (e.g., 5°C), such as the entropy value corresponding to a future flow rate of 300 cubic meters per hour being 1750 kW. The forward-looking heat load demand index is calculated based on the forecast curve and the heat loss of the pipeline network, such as 800 kW in the next 30 minutes. The matching relationship is used to calculate the supply-demand ratio, such as 1750 divided by 800 equals 2.19, with a limit of 1.0, indicating sufficient waste heat, and the feedforward instruction is to maintain the current opening or appropriately reduce the auxiliary heat source. The time decay weight uses an exponential function; for example, the weight is 0.5 when the time interval is 30 minutes, 0.25 when it is 60 minutes, and the weight is higher for the closer the future. Weighted fusion refers to merging the feedforward instruction (such as 70% opening) with the current instruction (such as 65%) according to the weights. For example, if the weights are each 50%, the optimized instruction will be 67.5%, which realizes the early response to future changes.

[0041] The beneficial effects of the above technical solution are as follows: by introducing reclaimed water scheduling and heat load prediction, feedforward regulation of control is realized, which makes up for the lag of feedback control; prediction noise is smoothed by the moving average method; the reliability of short-term prediction is higher than that of long-term prediction by the time decay weight; and the weighted fusion of feedforward and feedback realizes the organic combination of current control and future prediction, thereby improving the system's response speed and stability to load changes.

[0042] In some embodiments of this application, it also includes: The anomaly detection module is used to determine whether the waste heat source of reclaimed water is abnormal.

[0043] In some embodiments of this application, the anomaly detection module is used for: The temperature parameter sequence of the reclaimed water supply system is continuously monitored. When the temperature value of multiple consecutive sampling cycles is lower than the minimum usable temperature threshold of reclaimed water, it is determined to be an abnormal condition of the waste heat source of reclaimed water. In response to the abnormal operating condition of the waste heat source, the standby heating mode is triggered, the opening adjustment command is forcibly set to zero, and the reclaimed water heat exchange branch is shut down. Increase the power setting of the auxiliary heating equipment to meet the calculated value of the circulating water heat load demand index; An alarm signal for an abnormal waste heat source is generated, and a timer is started. When the duration of the abnormality exceeds the preset switching delay, the control mode is permanently switched to pure auxiliary heating mode until a manual reset command is received.

[0044] In this embodiment, continuous monitoring refers to sampling every 1 minute. An anomaly is triggered when the temperature is below the minimum usable temperature threshold (e.g., 12°C) for three consecutive sampling cycles (i.e., 3 minutes), preventing malfunctions caused by momentary fluctuations. In standby heating mode, the reclaimed water side valve is forcibly closed (0% opening) to prevent low-temperature reclaimed water from entering the heat exchanger and affecting the circulating water temperature. The auxiliary heat source power is set to the smaller of the heat load demand index (e.g., 683 kW) and 80% of the rated power (e.g., 800 kW), i.e., 683 kW, ensuring that demand is met while retaining a 20% margin. Anomaly alarm signals are sent to maintenance personnel via audible and visual alarms and SMS notifications. The preset switching delay is set to 30 minutes. If the reclaimed water temperature does not recover to above the threshold within 30 minutes, the system is permanently switched to pure auxiliary heating mode to prevent repeated switching from causing system instability. Manual reset is required after confirming fault resolution.

[0045] The beneficial effects of the above technical solution are: continuous monitoring and delayed judgment avoid erroneous switching caused by instantaneous temperature fluctuations; forced closure of the reclaimed water branch prevents cold shock to the system from the low-temperature medium; and permanent switching and manual reset mechanisms ensure system safety under abnormal operating conditions and avoid the risks that may be brought about by automatic recovery.

[0046] To further illustrate the technical concept of this invention, the technical solution of this invention will now be described in conjunction with specific application scenarios.

[0047] Correspondingly, such as Figure 2 As shown, this application also provides a circulating water heating control method based on waste heat from reclaimed water, including: S110: Obtain the temperature parameter sequence and flow parameter sequence of the reclaimed water supply system, simultaneously collect the return water temperature, target water supply temperature and pipeline circulation flow of the circulating water system, and collect the ambient temperature and reclaimed water source type identifier. S120: Calculate the available waste heat entropy value of the reclaimed water based on the temperature parameter sequence and flow rate parameter sequence. The available waste heat entropy value represents the total amount of usable heat energy carried by the reclaimed water. S130: Based on the reclaimed water source type identifier, query the preset water quality thermal resistance mapping table, and combine it with the stability characteristics of the temperature parameter sequence to generate a waste heat quality grading index. S140: Based on the difference between the return water temperature and the target supply water temperature, and combined with the pipeline circulation flow rate and pipeline heat loss characteristic parameters, calculate the circulating water heat load demand index, which represents the amount of heat energy required to maintain the target temperature. S150: The waste heat quality classification index is fused with the available waste heat entropy value to generate the reclaimed water side heating capacity index, and the heating capacity index is thermodynamically matched with the circulating water heat load demand index to generate power distribution benchmark parameters. S160: In response to the power allocation reference parameters, determine the valve opening adjustment command of the reclaimed water heat exchange branch and the power setting value of the auxiliary heating equipment, and generate a set of circulating water heating control commands. The set of control commands is used to coordinate the collaborative operation of reclaimed water waste heat utilization and auxiliary heat source.

[0048] In the description of the above embodiments, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0049] Although the invention has been described above with reference to embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of the invention. In particular, as long as there is no structural conflict, the features in the embodiments disclosed in this invention can be combined with each other in any way. The fact that not all of these combinations are described in this specification is merely for the sake of brevity and resource conservation.

[0050] It will be understood by those skilled in the art that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A circulating water heating control system based on waste heat from reclaimed water, characterized in that, include: The data acquisition module is used to acquire the temperature parameter sequence and flow parameter sequence of the reclaimed water supply system, and simultaneously acquire the return water temperature, target water supply temperature and pipeline circulation flow of the circulating water system, as well as the ambient temperature and reclaimed water source type identifier. The entropy calculation module is used to calculate the available waste heat entropy value of the reclaimed water based on the temperature parameter sequence and the flow parameter sequence. The available waste heat entropy value represents the total amount of usable heat energy carried by the reclaimed water. The quality generation module is used to query a preset water quality thermal resistance mapping table based on the reclaimed water source type identifier, and generate a waste heat quality grading index by combining the stability characteristics of the temperature parameter sequence. The demand calculation module is used to calculate the circulating water heat load demand index based on the difference between the return water temperature and the target supply water temperature, combined with the pipeline circulation flow rate and pipeline heat loss characteristic parameters. The circulating water heat load demand index represents the amount of heat energy supplement required to maintain the target temperature. The fusion analysis module is used to fuse the waste heat quality classification index with the available waste heat entropy value to generate the reclaimed water side heating capacity index, and to calculate the thermodynamic matching degree between the heating capacity index and the circulating water heat load demand index to generate power allocation benchmark parameters. The heating control module is used to respond to the power distribution reference parameters, determine the valve opening adjustment command of the reclaimed water heat exchange branch and the power setting value of the auxiliary heating equipment, and generate a set of circulating water heating control commands. The set of control commands is used to coordinate the collaborative operation of reclaimed water waste heat utilization and auxiliary heat source.

2. The circulating water heating control system based on waste heat from reclaimed water according to claim 1, characterized in that, The quality generation module is used for: The temperature parameter sequence is subjected to a sliding window standard deviation calculation, with the window length set to 5 to 10 sampling periods, to generate a temperature fluctuation index; Based on the comparison result between the temperature fluctuation index and the preset stability threshold, a temperature stability coefficient is generated. When the temperature fluctuation index is less than the preset stability threshold, the temperature stability coefficient is 1. When the temperature fluctuation index is greater than or equal to the preset stability threshold, the temperature stability coefficient is the ratio of the preset stability threshold to the temperature fluctuation index. Based on the reclaimed water source type identifier, distinguish between industrial cooling water, domestic sewage, or process condensate, and look up the corresponding thermal resistance coefficient; The waste heat quality grading index is generated by taking a weighted geometric average of the temperature stability coefficient and the thermal resistance coefficient.

3. The circulating water heating control system based on waste heat from reclaimed water according to claim 1, characterized in that, The demand calculation module is used for: Calculate the absolute value of the difference between the target supply water temperature and the return water temperature to obtain the instantaneous temperature rise requirement, and calculate the instantaneous heat load based on the pipeline circulation flow rate and the specific heat capacity of water. Based on the thermal conductivity of the insulation layer, the outer diameter and length of the pipeline, and the ambient temperature, the friction loss rate of the pipeline is calculated. Obtain the current ambient temperature and the typical design temperature of the area where the circulating water pipe network is located, and calculate the ambient temperature difference adjustment coefficient; The circulating water heat load demand index is generated by integrating the instantaneous heat load, the heat loss rate along the pipeline, and the ambient temperature difference adjustment coefficient.

4. The circulating water heating control system based on waste heat from reclaimed water according to claim 1, characterized in that, The fusion analysis module is used for: The ratio of the available waste heat entropy value to the circulating water heat load demand index is calculated to obtain the supply-demand ratio. The supply-demand ratio is then limited. When the supply-demand ratio is greater than 1, the value is 1. When the supply-demand ratio is less than 0, the value is 0. When the supply-demand ratio is between 0 and 1, the original value is maintained. Obtain the logarithmic mean temperature difference and heat transfer coefficient of the reclaimed water heat exchanger, calculate the maximum theoretical heat transfer of the heat exchanger, compare the maximum theoretical heat transfer with the available waste heat entropy value, and generate a heat exchange efficiency constraint coefficient. The heat exchange efficiency constraint coefficient is the minimum value between the ratio of the two and 1. Based on the degree of deviation between the current ambient temperature and the standard operating temperature, a climate regulation factor is generated; The supply-demand ratio, heat exchange efficiency constraint coefficient, and climate regulation factor are weighted and fused to generate power allocation benchmark parameters.

5. The circulating water heating control system based on waste heat from reclaimed water according to claim 1, characterized in that, The fusion analysis module is used for: Obtain the current opening position of the regulating valve in the reclaimed water heat exchange branch and the valve flow characteristic curve, wherein the flow characteristic curve includes linear characteristic, equal percentage characteristic or fast opening characteristic; The product of the power allocation reference parameter and the circulating water heat load demand index is used as the target heat load to be borne by the reclaimed water side. Based on the target heat load, specific heat capacity of reclaimed water and inlet / outlet temperature difference in the temperature parameter sequence, calculate the required reclaimed water flow rate adjustment; Based on the valve flow characteristic curve, the reclaimed water flow rate adjustment is mapped to the theoretical valve opening. The difference between the theoretical valve opening and the current opening position is calculated to generate the opening adjustment increment, which is limited by the valve's maximum allowable adjustment rate, and the final opening adjustment command is generated.

6. The circulating water heating control system based on waste heat from reclaimed water according to claim 1, characterized in that, The heating control module is used for: Determine the maximum effective heat exchange threshold of the reclaimed water heat exchange branch, wherein the maximum effective heat exchange threshold is set by the reclaimed water flow rate and the minimum allowable discharge temperature of the reclaimed water. The circulating water heat load demand index is compared with the maximum effective heat exchange threshold. When the circulating water heat load demand index is less than or equal to the maximum effective heat exchange threshold, the power setting value of the auxiliary heating equipment is set to zero. When the circulating water heat load demand index is greater than the maximum effective heat exchange threshold, the difference between the circulating water heat load demand index and the maximum effective heat exchange threshold is used to obtain the auxiliary heat load gap. Based on the real-time efficiency curve of the auxiliary heating equipment, the optimal operating power point corresponding to the auxiliary heat load gap is queried. The optimal operating power point is the minimum power value on the efficiency curve that is closest to the auxiliary heat load gap and not less than the auxiliary heat load gap. The optimal operating power point is used as the power setting value.

7. The circulating water heating control system based on waste heat from reclaimed water according to claim 1, characterized in that, Also includes: Instruction optimization module, used for: Obtain the reclaimed water flow scheduling plan and the heat load forecast curve of the circulating water system for future time periods; Based on the statistical characteristics of the reclaimed water flow scheduling plan and historical temperature parameter sequences, the prospective available waste heat entropy value is calculated using the moving average method. Based on the aforementioned heat load forecast curve and pipeline heat loss characteristic parameters, the forward heat load demand index is calculated. Based on the matching relationship between the prospective available waste heat entropy value and the prospective heat load demand index, a feedforward control command sequence is generated; Calculate the time interval between the current moment and the corresponding moment in the feedforward control command sequence, and generate a time decay weight, wherein the time decay weight decays exponentially with the time interval; The feedforward control command sequence is weighted and fused with the current control command according to the time decay weight to generate the optimized control command.

8. The circulating water heating control system based on waste heat from reclaimed water according to claim 1, characterized in that, Also includes: The anomaly detection module is used to determine whether the waste heat source of reclaimed water is abnormal.

9. The circulating water heating control system based on waste heat from reclaimed water according to claim 8, characterized in that, The anomaly detection module is used for: The temperature parameter sequence of the reclaimed water supply system is continuously monitored. When the temperature value of multiple consecutive sampling cycles is lower than the minimum usable temperature threshold of reclaimed water, it is determined to be an abnormal condition of the waste heat source of reclaimed water. In response to the abnormal operating condition of the waste heat source, the standby heating mode is triggered, the opening adjustment command is forcibly set to zero, and the reclaimed water heat exchange branch is shut down. Increase the power setting of the auxiliary heating equipment to meet the calculated value of the circulating water heat load demand index; An alarm signal for an abnormal waste heat source is generated, and a timer is started. When the duration of the abnormality exceeds the preset switching delay, the control mode is permanently switched to pure auxiliary heating mode until a manual reset command is received.

10. A circulating water heating control method based on waste heat from reclaimed water, applied to the circulating water heating control system based on waste heat from reclaimed water as described in any one of claims 1-9, characterized in that, include: Acquire the temperature and flow parameter sequences of the reclaimed water supply system, simultaneously collect the return water temperature, target supply temperature, and pipeline circulation flow of the circulating water system, and collect the ambient temperature and reclaimed water source type identifier. The available waste heat entropy value of the reclaimed water is calculated based on the temperature parameter sequence and the flow rate parameter sequence. The available waste heat entropy value represents the total amount of usable heat energy carried by the reclaimed water. Based on the reclaimed water source type identifier, a preset water quality thermal resistance mapping table is queried, and combined with the stability characteristics of the temperature parameter sequence, a waste heat quality grading index is generated. Based on the difference between the return water temperature and the target supply water temperature, and combined with the pipeline circulation flow rate and pipeline heat loss characteristic parameters, the circulating water heat load demand index is calculated. The circulating water heat load demand index represents the amount of heat energy required to maintain the target temperature. The waste heat quality classification index is fused with the available waste heat entropy value to generate a reclaimed water side heating capacity index. The heating capacity index is then thermodynamically matched with the circulating water heat load demand index to generate power allocation benchmark parameters. In response to the power allocation reference parameters, the valve opening adjustment command of the reclaimed water heat exchange branch and the power setting value of the auxiliary heating equipment are determined, and a circulating water heating control command set is generated. The control command set is used to coordinate the collaborative operation of reclaimed water waste heat utilization and auxiliary heat source.

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