Wind energy heating unit control method and system utilizing waste heat of circulating water of thermal power plant

Abstract

The invention discloses a wind energy heating unit control method and system utilizing waste heat of circulating water of a thermal power plant. A control method for a wind energy heating unit utilizing waste heat of circulating water of a thermal power plant is characterized in that a fan is used for driving a heat pump to heat the temperature of hot water on a user side after a circulating water system of the thermal power plant enters a heat exchanger, and the hot water is used by a heat user. The flow of cooling water entering the evaporator is adjusted, and it is guaranteed that the flow meets the heating capacity requirement of the air heating unit; heat storage or heat release of a heat storage tank is controlled, specifically, heat storage or heat release is adjusted according to the return water temperature of a heat user on the basis of heat balance within a short time, and the change of the return water temperature of the heat user is stabilized; and controlling the output of the wind-heat unit, wherein the wind-heat unit adjusts the output of the wind-heat unit according to the return water temperature of the heat user on the basis of heat balance within a long time. The system can replace or reduce steam extraction of a thermal power generating unit, meanwhile, wind energy is used for heat supply, and clean energy heat supply is achieved.

Description

Technical Field

[0001] This invention relates to the field of waste heat from circulating water in thermal power plants and wind power heating units, and in particular to a control method and system for wind power heating units that utilize waste heat from circulating water in thermal power plants. Background Technology

[0002] The circulating water in thermal power units serves to cool the condenser. After absorbing heat from the condenser, the relatively low-temperature cooling water enters a cooling tower for further cooling before returning to the condenser, or it is directly discharged into an external river. Although the temperature of the cooling water increases after absorbing heat from the condenser, it remains low and is considered low-grade heat, which generally cannot be effectively utilized again.

[0003] my country has abundant wind energy resources with the potential for large-scale development. However, due to the fluctuating and intermittent nature of wind energy, the most pressing issue accompanying the large-scale grid connection of new energy sources is the difficulty in completely resolving the grid integration contradiction, which seriously affects the improvement of wind power efficiency and profitability.

[0004] In April 2020, the state proposed prioritizing the development of local decentralized and distributed renewable energy resources, and vigorously promoting distributed renewable electricity, heat, and gas to enable users to directly utilize them locally. Emphasis was placed on non-electrical uses of renewable energy, such as heating, to significantly increase the proportion of renewable energy in clean heating in northern regions, thereby promoting a greater role for non-electrical uses of renewable energy in my country's energy transition.

[0005] Therefore, based on "utilization of waste heat from circulating water in thermal power plants" and "heating from wind turbine units", and in accordance with the principles of "energy matching and scientific energy use", the high-quality mechanical energy generated by wind turbines and the low-quality waste heat from thermal power plants are effectively integrated to promote the synergistic and diversified application of new energy sources and meet the comprehensive energy supply needs of demonstration buildings. Summary of the Invention

[0006] This invention provides a control method and system for a wind-powered heating unit utilizing waste heat from the circulating water in a thermal power plant. The circulating water outlet temperature of the cooling condenser in a thermal power plant's circulating water system is low, representing low-grade heat. This invention utilizes a fan-driven heat pump to elevate this low-grade heat to high-grade heat. After entering the heat exchanger, the heat pump heats the hot water on the user's side for consumption. This system can replace or reduce steam extraction from thermal power units while simultaneously utilizing wind power for heating, achieving clean energy heating.

[0007] The technical solution adopted in this invention is as follows: To achieve the above objectives, the present invention provides a control method and system for a wind power heating unit that utilizes the waste heat of circulating water in a thermal power plant, applicable to the control of wind power heating units that utilize the waste heat of circulating water in a thermal power plant.

[0008] A control method for a wind-powered heating unit utilizing waste heat from circulating water in a thermal power plant involves using a fan to drive a heat pump, heating the hot water on the user side after it enters the heat exchanger from the thermal power plant's circulating water system, and supplying it to the user. The control method, based on the input parameters and output signals of the heating controller, employs a cascade + feedforward control approach to maintain a stable return water temperature for the user. The control process includes: Evaporator inlet water flow control: Adjust the flow rate of cooling water entering the evaporator to ensure that it meets the heating demand of the air-heater unit; Thermal storage tank heat storage or release control: Based on the heat balance within a short time t1, adjust the heat storage or release according to the return water temperature of the heat user to smooth out the change in the return water temperature of the heat user. Air-heated unit output control: The air-heated unit output is adjusted according to the return water temperature of the heat users, based on the heat balance within a relatively long time t2. Among them, the heat storage or heat release control of the heat storage tank and the output control of the air-heat unit adopt the main controller and the auxiliary controller in series. The feedback value of the main controller is the return water temperature of the heat user T2, and the set value is the return water temperature set value of the heat user T2s. The feedback value of the secondary controller is the condenser return water temperature T4, and the set value is the output value of the main controller. The feedforward values ​​are calculated based on the predicted weather temperature and wind speed values ​​for a future period of time, the heat consumption of heat users H1 and the heat generation of wind turbine units H2, and then the feedforward values ​​are calculated based on the imbalance relationship and object characteristics. With the return water temperature T2 of the heat user as the main regulation target, the heat storage valve or heat release valve of the heat storage tank and the output of the air-heat unit are adjusted according to the regulation dead zone and different prediction feedforward values ​​to maintain the stability of the return water temperature of the heat user. When the wind turbine reaches its maximum output at the wind speed and the heat storage tank is unable to release heat, and the demand of heat users is still not met, the unit will start extracting steam or using a standby boiler.

[0009] The aforementioned control method for wind power generating units utilizing waste heat from circulating water in thermal power plants includes the following process for calculating the feedforward value F1 based on the imbalance relationship and object characteristics during the heat storage or release control process in the heat storage tank: 1) Calculate the heat consumption H1 (t1) of heat users based on the weather temperature T0 within a future period t1: (1) Where Ti is the indoor temperature demand of the heat user (°C), T0 is the outdoor weather temperature (°C), and A is the area of ​​the heating area (m²). 2 U is the loss coefficient (W / m) 2 *K), t1 is time, which can be selected according to the thermal inertia of the heating system, for example, 1 / 5 to 1 / 4 of the thermal inertia.

[0010] 2) Calculate the heat output H2(t1) of the wind-heat unit according to the wind speed v0 within a future period t1: (2) where, P is the air density (kg / m 3 ), B is the swept area (m 2 ), v0 is the wind speed (m / s). f(v0) is the wind-heat conversion function, which represents the ability of the fan to convert mechanical power into heat and is determined by the characteristics of the wind-heat unit; x0 is the heat loss coefficient, which represents the loss of heat generated by the wind-heat unit transferred to the heat user and is determined by the characteristics of the heat exchanger and the heat user; 3) Calculate the feedforward value F1: (3) where, K1 is the proportionality coefficient, which is determined according to the characteristics of the heat storage valve of the heat storage tank; K2 is the proportionality coefficient, which is determined according to the characteristics of the heat release valve of the heat storage tank; The heat supply controller executes the following control logic: If T2 - T2s > T2s1 and H1(t1) > H2(t1), it means that the current heat supply is greater than the demand, and the heat supply within a future period is greater than the demand. The PID control opens the heat storage valve of the heat storage tank, and the feedforward plays the role of opening the heat storage valve in advance to quickly store the excess heat in the heat storage tank; if T2 - T2s > T2s1 and H1(t1) < H2(t1), it means that the current heat supply is greater than the demand, but the heat supply within a future period is less than the demand. The PID control opens the heat storage valve of the heat storage tank, but the feedforward plays the role of closing the heat storage valve in advance. The final valve action is determined by the combination of PID and feedforward; If T2 - T2s < -T2s1 and H1(t1) > H2(t1), it means that the current heat supply is less than the demand, but the heat supply within a future period is greater than the demand. The PID control opens the heat release valve of the heat storage tank, but the feedforward plays the role of closing the heat release valve in advance. The final valve action is determined by the combination of PID and feedforward; if T2 - T2s < -T2s1 and H1(t1) < H2(t1), it means that the current heat supply is less than the demand, and the heat supply within a future period is less than the demand. The PID control opens the heat release valve of the heat storage tank, and the feedforward plays the role of opening the heat release valve in advance to quickly release the excess heat in the heat storage tank to the heat user.

[0011] If the deviation between the actual value T2 of the return water temperature of the heat user and the set value T2s exceeds the dead zone T2s2, the output of the wind-heat unit needs to be adjusted at this time; If T2 - T2s > T2s2, it means that the heat supply is much greater than the demand, and the output of the wind-heat unit needs to be reduced; if T2 - T2s < -T2s2, it means that the heat supply is much less than the demand, and the output of the wind-heat unit needs to be increased.

[0012] The dead zone thresholds T2s1, T2s2, and T2s3 satisfy T2s1 < T2s2 < T2s3 to enable different objects to act differently for different deviations.

[0013] In the control method of the wind energy heating unit using the waste heat of the circulating water in a thermal power plant, during the output control process of the wind-heat unit, the process of calculating the feedforward value F2 according to the imbalance relationship and object characteristics includes: The feedforward value F2 is calculated based on the predicted values of the weather temperature W and wind speed S within a future period t2, to calculate the heat consumption H1(t2) of the heat users and the heat production H2(t2) of the wind-heat unit; (4) Among them, t2 is the time, selected according to the heat inertia of the heating system, for example, taking 1 / 2 to 2 / 3 of the heat inertia.

[0014] (5) (6) Among them, K3 is the proportionality coefficient, determined according to the output characteristics of the wind-heat unit; The heat absorption of the wind-heat unit from the condenser cooling water is achieved by adjusting the inlet flow rate of the evaporator according to the output of the wind-heat unit and ensuring the stability of the condenser outlet water temperature.

[0015] In the control method of the wind energy heating unit using the waste heat of the circulating water in a thermal power plant, the control of the inlet flow rate of the evaporator adopts a closed-loop PID + feedforward control: the feedback value of the controller is the condenser outlet water temperature T3, the set value is the condenser outlet water temperature set value T3s, and the feedforward value F3 is set according to the output of the wind-heat unit and determined by the characteristics of the wind-heat unit; Calculation method of the controller feedback value F3: (7) Among them, K4 is the proportionality coefficient, G is the output of the wind-heat unit, the COP of the wind-heat unit = H2 / G = (G + H3) / G, and H3 is the heat absorption of the wind-heat unit from the condenser cooling water.

[0016] In the control method of the wind energy heating unit using the waste heat of the circulating water in a thermal power plant, the control process of the unit extraction steam or standby boiler is as follows: the feedback value of the controller is the return water temperature T2 of the heat users, and the set value is the return water temperature set value T2s of the heat users; if the processing of the wind-heat unit reaches the maximum, the heat storage capacity of the heat storage tank is 0, and when the deviation between the actual value T2 of the return water temperature of the heat users and the set value T2s exceeds the dead zone T2s3, the unit extraction steam or standby boiler is started at this time to ensure the heat user demand; the control adopts a conventional PID closed-loop control and is adjusted according to the deviation between the actual value T2 of the return water temperature of the users and the set value T2s.

[0017] The heating controller uses predictive technology to implement feedforward control. Its input parameters include weather temperature, wind speed, predicted weather temperature and wind speed for a future period, inlet and return water temperatures for heat users, condenser inlet and return water temperatures, evaporator inlet and outlet water temperatures, and evaporator inlet and return water temperatures and flow rates. The heating controller's output signals include control of the output of the air-cooled turbine unit, the thermal storage valves and heat release valves of the thermal storage tank, the evaporator inlet water flow rate, and the extraction or standby boiler of the unit.

[0018] A control system for a wind-powered heating unit utilizing waste heat from circulating water in a thermal power plant includes a thermal power unit, a wind-powered heating unit, and a heating controller. The wind-powered heating unit includes an evaporator, a condenser, a wind turbine, and a screw compressor. The thermal power unit includes a condenser, a cooling tower, an extraction steam and / or a standby boiler, a heat exchanger, heat users, and a heat storage tank. The heating controller, based on its input parameters and output signals, employs a cascade + feedforward control method to maintain a stable return water temperature for the heat users, ensuring their needs are met. Heat storage or release control in the heat storage tank is achieved by controllers PID1 and PID2 controlling the heat storage valve and heat release valve Y1 in series. The output control of the wind-powered heating unit is achieved by controllers PID3 and PID4 controlling the output control valve Y2 in series.

[0019] The control system for the wind power heating unit that utilizes the waste heat from the circulating water of a thermal power plant controls the evaporator water inlet flow rate through PID5 control of the evaporator water inlet valve Y3.

[0020] The control system for the wind power heating unit that utilizes the waste heat of the circulating water in the thermal power plant is implemented by PID6 controlling Y4 to activate the unit's steam extraction or standby boiler.

[0021] The heating controller employs cascade + feedforward control. The main controller's feedback value is the return water temperature T2 for heat users, and its setpoint is the return water temperature setpoint T2s for heat users. The secondary controller's feedback value is the condenser return water temperature T4, and its setpoint is the main controller's output value. The feedforward values ​​are calculated based on predicted weather temperatures W and wind speeds S over a future period t, calculating the heat consumption H1 for heat users and the heat output H2 of the air-cooled turbine unit. Then, the feedforward value is calculated based on the imbalance relationship and the characteristics of the components. With the return water temperature T2 for heat users as the primary regulating element, the controller adjusts the heat storage valves or heat release valves in the heat storage tank, the output of the air-cooled turbine unit, and the extraction steam or standby boiler of the unit according to the regulation dead zone and different predicted feedforward values ​​to maintain a stable return water temperature for heat users, thereby ensuring the heat users' needs are met.

[0022] The specific control process is as follows: (1) Assume that the system is initially in equilibrium, the wind-heat unit tracks the maximum output, the heat storage tank heat storage and heat release valves are closed, the unit steam extraction and standby boiler are closed, and the actual value T2 of the heat user return water temperature is equal to the set value T2s. At this time, the system is in equilibrium.

[0023] (2) Due to external influences, the actual return water temperature T2 of the heat user begins to change. When the deviation between T2 and the set value T2s exceeds the dead zone T2s1 (T2s1 can be taken as 0.5℃), the heat storage tank should be adjusted first to store or release heat: If T2-T2s>T2s1, it means the heat supply is greater than the demand. Open the heat storage valve of the heat storage tank to store the excess heat in the heat storage tank. If T2-T2s<-T2s1, it means the heat supply is less than the demand. Open the heat release valve of the heat storage tank to release the excess heat in the heat storage tank to the heat user.

[0024] The control system adopts cascade + feedforward control: the feedback value of the main controller is the return water temperature of the heat user T2, and the setpoint is the return water temperature setpoint of the heat user T2s; the feedback value of the secondary controller is the return water temperature of the condenser T4, and the setpoint is the output value of the main controller. The feedforward value F1 is calculated based on the predicted values ​​of weather temperature W and wind speed S within a future period t1. The heat consumption of the heat user H1 (t1) and the heat generation of the wind turbine H2 (t1) are calculated, and then the feedforward value is calculated based on the imbalance relationship and the characteristics of the object. The feedforward value F2 is calculated based on the predicted values ​​of weather temperature W and wind speed S within a future period t2, to calculate the heat consumption H1 (t2) of the heat user and the heat generation H2 (t2) of the wind turbine unit.

[0025] Beneficial effects of the invention: 1. This invention relates to a control method and system for a wind-powered heating unit utilizing waste heat from circulating water in thermal power plants. A fan drives a heat pump to upgrade low-grade heat to high-grade heat, which then enters a heat exchanger to heat the hot water on the user's side for consumption. This system can replace or reduce steam extraction from thermal power units, while simultaneously utilizing wind power for heating, achieving clean energy heating.

[0026] 2. The implementation of the wind power heating unit control method and system utilizing the waste heat of circulating water in thermal power plants will help promote cost reduction, efficiency improvement, and diversified development in my country's wind power utilization field, and drive technological innovation and transformation and upgrading of renewable energy systems. Attached Figure Description

[0027] Figure 1 The diagram shows the composition of the wind power heating unit control system that utilizes the waste heat from the circulating water of a thermal power plant according to the present invention. Figure 2 The diagram shows a schematic of a heating controller based on predictive technology. Figure 3 The figure shows the relationship between wind speed and performance conversion efficiency of a wind-heated power unit. Detailed Implementation

[0028] To make the technical concept and advantages of the invention clearer, the technical solution of the present invention will be further described in detail below with reference to the accompanying drawings. It should be understood that the following embodiments are merely preferred embodiments for explaining and illustrating the present invention, and should not be considered as, nor constitute a limitation on, the scope of patent protection claimed by the present invention.

[0029] Example 1 See Figure 2 This invention describes the structure of a heating controller based on predictive technology. The invention utilizes a wind-powered heating unit control method based on waste heat from the circulating water of a thermal power plant. A fan drives a heat pump to heat the hot water on the user side of the thermal power plant's circulating water system after it enters the heat exchanger, providing heating to the user. The control method, based on the heating controller's input parameters and output signals, employs a cascade + feedforward control approach to maintain a stable return water temperature for the user. The heating controller control process includes: Evaporator inlet water flow control: Adjust the flow rate of cooling water entering the evaporator to ensure that it meets the heating demand of the air-heater unit; Thermal storage tank heat storage or release control: Based on the heat balance within a short time t1, adjust the heat storage or release according to the return water temperature of the heat user to smooth out the change in the return water temperature of the heat user. Air-heated unit output control: The air-heated unit output is adjusted according to the return water temperature of the heat users, based on the heat balance within a relatively long time t2. Among them, the heat storage or heat release control of the heat storage tank and the output control of the air-heat unit adopt the main controller and the auxiliary controller in series. The feedback value of the main controller is the return water temperature of the heat user T2, and the set value is the return water temperature set value of the heat user T2s. The feedback value of the secondary controller is the condenser return water temperature T4, and the set value is the output value of the main controller. The feedforward values ​​are calculated based on the predicted weather temperature and wind speed values ​​for a future period of time, the heat consumption of heat users H1 and the heat generation of wind turbine units H2, and then the feedforward values ​​are calculated based on the imbalance relationship and object characteristics. With the return water temperature T2 of the heat user as the main regulation target, the heat storage valve or heat release valve of the heat storage tank and the output of the air-heat unit are adjusted according to the regulation dead zone and different prediction feedforward values ​​to maintain the stability of the return water temperature of the heat user. When the wind turbine reaches its maximum output at the wind speed and the heat storage tank cannot release heat, it still cannot meet the heat user's demand, so the unit starts extracting steam or using a standby boiler.

[0030] The heating controller 11 based on predictive technology of this invention has the following input parameters: weather temperature, wind speed, predicted weather temperature and wind speed for a future period, inlet water temperature T1 for heat users, return water temperature T2 for heat users, condenser inlet water temperature T4, condenser return water temperature T3, evaporator inlet water temperature T5, evaporator inlet water flow rate L5, and evaporator return water temperature T6. The heating controller output signals include control signals for the thermal storage tank valves and heat release valves Y1, the output of the air-cooled turbine unit Y2, the evaporator inlet water flow rate Y3, and the control signal for the unit's extraction steam or standby boiler Y4. The thermal storage tank valves and heat release valves are controlled via Y1, the air-cooled turbine unit output is controlled via Y2, the evaporator inlet water flow rate is controlled via Y3, and the unit's extraction steam or standby boiler is controlled via Y4.

[0031] The overall control strategy of the heating controller is as follows: The thermal storage tank is based on a short-term heat balance (t1), and the heat storage or release is adjusted according to the return water temperature of the heat users to mitigate temperature fluctuations. The air-cooled turbine unit is based on a longer-term heat balance (t2), and its output is adjusted according to the return water temperature of the heat users. The cooling water flow rate entering the evaporator is adjusted to ensure it meets the heating demand of the air-cooled turbine unit. In special circumstances (when the air-cooled turbine unit reaches its maximum output at the specified wind speed and the thermal storage tank cannot release heat, still failing to meet the heat user demand), the unit will start extracting steam or using a standby boiler to ensure the return water temperature of the heat users.

[0032] The main heating controller system employs cascade + feedforward control. The main controller's feedback value is the return water temperature T2 for heat users, and its setpoint is the return water temperature setpoint T2s for heat users. The secondary controller's feedback value is the condenser return water temperature T4, and its setpoint is the main controller's output value. The feedforward values ​​are calculated based on predicted weather temperature and wind speed over a future period, determining the heat demand H1 for heat users and the heat output H2 of the air-cooled turbine unit. These feedforward values ​​are then calculated based on the imbalance relationship and the characteristics of the components. With the return water temperature T2 for heat users as the primary control target, the system adjusts the heat storage valves or heat release valves in the heat storage tank, the output of the air-cooled turbine unit, and the extraction steam or standby boiler according to the control dead zone and different predicted feedforward values. This maintains a stable return water temperature for heat users, thereby ensuring their needs are met.

[0033] For heat users, the building's insulation and other characteristics are fixed. The heat user's inlet water flow rate L1 is usually not adjustable within a large range (maintained at a certain value). The heat user's inlet water temperature T1 is determined by the heat exchanger. At this time, it is only necessary to keep the heat user's outlet water temperature T2 within a certain range to ensure the heat user's demand and the indoor temperature of residents.

[0034] The specific control charts are explained below: (1) Assume that the system is initially in equilibrium, the wind-heat unit tracks the maximum output, the heat storage tank heat storage and heat release valves are closed, the unit steam extraction and standby boiler are closed, and the actual value T2 of the heat user return water temperature is equal to the set value T2s. At this time, the system is in equilibrium.

[0035] (2) Due to external influences, the actual return water temperature T2 of the heat user begins to change. When the deviation between T2 and the set value T2s exceeds the dead zone T2s1 (T2s1 can be taken as 0.5℃), the heat storage tank should be adjusted first to store or release heat: If T2-T2s>T2s1, it means the heat supply is greater than the demand. Open the heat storage valve of the heat storage tank to store the excess heat in the heat storage tank. If T2-T2s<-T2s1, it means the heat supply is less than the demand. Open the heat release valve of the heat storage tank to release the excess heat in the heat storage tank to the heat user.

[0036] The control system adopts cascade + feedforward control: the feedback value of the main controller is the return water temperature of the heat user T2, and the setpoint is the return water temperature setpoint of the heat user T2s; the feedback value of the secondary controller is the return water temperature of the condenser T4, and the setpoint is the output value of the main controller. The feedforward value F1 is calculated based on the predicted weather temperature and wind speed within a future period t1. The heat consumption of the heat user H1 (t1) and the heat generation of the wind turbine H2 (t1) are calculated, and then the feedforward value is calculated based on the imbalance relationship and the characteristics of the object.

[0037] 1) Calculate the heat consumption H1 (t1) of heat users based on the weather temperature T0 within a future period t1: (1) Where Ti is the indoor temperature demand of the heat user (°C), T0 is the outdoor weather temperature (°C), and A is the area of ​​the heating area (m²). 2 U is the loss coefficient (W / m) 2 *K), t1 is time, which can be selected according to the thermal inertia of the heating system, for example, 1 / 5 to 1 / 4 of the thermal inertia.

[0038] 2) Calculate the heat output H2(t1) of the wind turbine unit based on the wind speed v0 within a future time period t1: (2) Where P is the air density (kg / m³) 3 B is the swept area (m²) 2 v0 is the wind speed (m / s). f(v0) is the wind-to-heat conversion function, representing the fan's ability to convert mechanical power into heat. It is determined by the characteristics of the air-heater unit and can be obtained through experiments or fan characteristic curves. x0 is the heat loss coefficient, representing the loss of heat generated by the air-heater unit to the heat user. It is determined by the heat exchanger and the heat user characteristics and can be obtained through experiments.

[0039] 3) Calculate the feedforward value F1: (3) Among them, K1 is a proportionality coefficient, which is determined according to the characteristics of the heat storage valve of the heat storage tank. K2 is a proportionality coefficient, which is determined according to the characteristics of the heat release valve of the heat storage tank.

[0040] If T2 - T2s > T2s1 and H1(t1) > H2(t1), it means that the current heat supply is greater than the demand, and the heat supply will be greater than the demand in a period of time in the future. The PID control opens the heat storage valve of the heat storage tank, and the feedforward plays a role in opening the heat storage valve in advance, quickly storing the excess heat in the heat storage tank; if T2 - T2s > T2s1 and H1(t1) < H2(t1), it means that the current heat supply is greater than the demand, but the heat supply will be less than the demand in a period of time in the future. The PID control opens the heat storage valve of the heat storage tank, but the feedforward plays a role in closing the heat storage valve in advance, and the final valve action is determined by the combination of PID and feedforward. If T2 - T2s < -T2s1 and H1(t1) > H2(t1), it means that the current heat supply is less than the demand, but the heat supply will be greater than the demand in a period of time in the future. The PID control opens the heat release valve of the heat storage tank, but the feedforward plays a role in closing the heat release valve in advance, and the final valve action is determined by the combination of PID and feedforward; if T2 - T2s < -T2s1 and H1(t1) < H2(t1), it means that the current heat supply is less than the demand, and the heat supply will be less than the demand in a period of time in the future. The PID control opens the heat release valve of the heat storage tank, and the feedforward plays a role in opening the heat release valve in advance, quickly releasing the excess heat in the heat storage tank to the heat users.

[0041] (3) Further, if the deviation between the actual value T2 of the return water temperature of the heat users and the set value T2s exceeds the dead zone T2s2 (T2s2 can be taken as 1°C), at this time, it is necessary to adjust the output of the air-heated unit.

[0042] If T2 - T2s > T2s2, it means that the heat supply is much greater than the demand, and it is necessary to reduce the output of the air-heated unit; if T2 - T2s < -T2s2, it means that the heat supply is much less than the demand, and it is necessary to increase the output of the air-heated unit.

[0043] The dead zone thresholds satisfy T2s1 < T2s2 < T2s3. For example, T2s1 = 0.5°C, T2s2 = 1°C, and T2s3 = 1.5°C can be taken to achieve different actions for different objects with different deviations.

[0044] The controller adopts the same control method as the heat storage tank control method, but the parameters of the PID controller are different.

[0045] The feedforward value F2 is the predicted values of the weather temperature W and wind speed S within a period of time t2 in the future, and is used to calculate the heat consumption H1(t2) of the heat users and the heat production H2(t2) of the air-heated unit.

[0046] (4) Where t2 is time, which is selected based on the thermal inertia of the heating system, for example, 1 / 2 to 2 / 3 of the thermal inertia.

[0047] (5) (6) K3 is a proportional coefficient, which is determined based on the output characteristics of the air-heater unit.

[0048] (4) The heat absorbed by the air-heated unit from the condenser cooling water is achieved by adjusting the evaporator inlet water flow rate, based on the air-heated unit output and to ensure stable condenser outlet water temperature. The controller adopts closed-loop PID + feedforward control. The controller feedback value is the condenser outlet water temperature T3, the setpoint value is the condenser outlet water temperature setpoint T3s, and the feedforward value F3 is set according to the air-heated unit output and determined by the characteristics of the air-heated unit. (7) Where K4 is the proportional coefficient, G is the output of the air-heated turbine unit, and the COP of the air-heated turbine unit is H2 / G = (G+H3) / G, where H3 is the heat absorbed by the air-heated turbine unit from the condenser cooling water. For example, Figure 3 To determine the relationship between wind speed and performance conversion efficiency of a certain air-heated unit, F3 can be determined based on the unit's output and the COP value shown in the figure.

[0050] In special circumstances, if the air-heater unit reaches its maximum capacity, the heat storage tank has zero heat storage, and the deviation between the actual return water temperature T2 and the setpoint T2s exceeds the dead zone T2s3 (T2s2 can be taken as 1.5℃), the unit will activate steam extraction or the standby boiler to ensure the heat user's needs are met. The control employs conventional PID closed-loop control, adjusting based on the deviation between the actual return water temperature T2 and the setpoint T2s.

[0051] Example 2 See Figure 1 , Figure 2 This embodiment describes a wind power heating unit control system that utilizes waste heat from the circulating water of a thermal power plant. The wind power unit consists of an evaporator, condenser, wind turbine, screw compressor, etc., while the thermal power unit includes a condenser, cooling tower, extraction steam, standby boiler, heat exchanger, heat users, thermal storage tank, and a heating controller based on predictive technology.

[0052] This invention relates to a wind power heating unit control system that utilizes the waste heat from the circulating water of a thermal power plant. Through a heating controller, based on the input parameters and output signals of the heating controller, a cascade + feedforward control method is adopted to maintain a stable return water temperature for heat users and ensure their needs are met. Specifically, the heat storage or heat release control of the heat storage tank is achieved by controllers PID1 and PID2 in series controlling the heat storage valve and the heat release valve Y1 (adjusting the valve opening). The output control of the wind power unit is achieved by controllers PID3 and PID4 in series controlling the output control Y2 of the wind power unit (adjusting the fan blade pitch angle).

[0053] The evaporator water inlet flow rate is controlled by PID5 through the evaporator inlet valve Y3 (adjusting the opening of the inlet valve).

[0054] The activation of the unit's extraction steam or standby boiler is achieved through PID6 control Y4 (adjusting the opening of the extraction steam valve).

[0055] Compared to existing technologies, this invention, based on "waste heat utilization of circulating water in thermal power plants" and "heating from wind turbine units," and adhering to the principles of "energy matching and scientific energy use," effectively unifies the high-quality mechanical energy generated by wind turbines with the low-quality waste heat from thermal power plants. This promotes the synergistic and diversified application of new energy sources and meets the comprehensive energy supply needs of demonstration buildings. The implementation of this research will help reduce costs, increase efficiency, and promote diversified development in my country's wind energy utilization sector, as well as drive technological innovation and transformation and upgrading of renewable energy systems.

Claims

1. A control method for a wind-powered heating unit utilizing waste heat from circulating water in a thermal power plant, comprising using a fan to drive a heat pump to heat the user-side hot water after it enters the heat exchanger from the thermal power plant's circulating water system, for use by the heating user, characterized in that: The control method is based on the input parameters and output signals of the heating controller, and adopts a cascade + feed-forward control method to keep the return water temperature of heat users stable. The control process of the heating controller includes: Evaporator inlet flow control: Adjust the cooling water flow entering the evaporator to ensure that it meets the heat production demand of the air-heat unit. Heat storage or heat release control of the heat storage tank: Based on the heat balance within a short time t1, adjust heat storage or heat release according to the return water temperature of heat users to suppress the change of the return water temperature of heat users. Output control of the air-heat unit: The air-heat unit adjusts its output based on the heat balance within a long time t2 according to the return water temperature of heat users. Among them, the heat storage or heat release control of the heat storage tank and the output control of the air-heat unit adopt the series connection of the main controller and the sub-controller. The feedback value of the main controller is the return water temperature T2 of heat users, and the set value is the set value T2s of the return water temperature of heat users. The feedback value of the sub-controller is the return water temperature T4 of the condenser, and the set value is the output value of the main controller. The feed-forward value is calculated based on the predicted values of weather temperature and wind speed within a future period of time, calculating the heat consumption H1 of heat users and the heat production H2 of the air-heat unit, and then calculating the feed-forward value according to the imbalance relationship and object characteristics. Taking the return water temperature T2 of heat users as the main regulation object, adjust the heat storage valve or heat release valve of the heat storage tank and the output of the air-heat unit respectively according to the regulation dead zone and different predicted feed-forward values to keep the return water temperature of heat users stable. When the air-heat unit reaches the maximum output at this wind speed and the heat storage tank cannot release heat, and still cannot meet the demand of heat users, the unit starts to extract steam or use the standby boiler.

2. The control method for a wind power generating unit utilizing waste heat from circulating water in a thermal power plant according to claim 1, characterized in that: During the heat storage or heat release control process of the heat storage tank, the process of calculating the feed-forward value F1 according to the imbalance relationship and object characteristics includes: 1) Calculate the heat consumption H1(t1) of heat users according to the weather temperature T0 within a future period of time t1: （1） Where Ti is the indoor temperature demand of the heat user (°C), T0 is the outdoor weather temperature (°C), and A is the area of ​​the heating area (m²). 2 U is the loss coefficient (W / m) 2 *K), t1 is time, which can be selected according to the thermal inertia of the heating system, for example, 1 / 5 to 1 / 4 of the thermal inertia; 2) Calculate the heat production H2(t1) of the air-heat unit according to the wind speed v0 within a future period of time t1: （2） Where P is the air density (kg / m³) 3 B is the swept area (m²) 2 v0 is the wind speed (m / s); f(v0) is the wind-heat conversion function, which represents the ability of the fan to convert mechanical power into heat, and is determined by the characteristics of the air-heat unit; x0 is the heat loss coefficient, which represents the loss of heat generated by the air-heat unit to the heat user, and is determined by the characteristics of the heat exchanger and the heat user. 3) Calculate the feed-forward value F1: （3） Among them, K1 is the proportional coefficient, which is determined according to the characteristics of the heat storage valve of the heat storage tank; K2 is the proportional coefficient, which is determined according to the characteristics of the heat release valve of the heat storage tank. The heating controller executes the following control logic: If T2 - T2s > T2s1 and H1(t1) > H2(t1), it means that the current heat supply is greater than the demand, and the heat supply within a future period of time is greater than the demand. The PID control opens the heat storage valve of the heat storage tank, and the feed-forward plays the role of opening the heat storage valve in advance to quickly store the excess heat in the heat storage tank; if T2 - T2s > T2s1 and H1(t1) < H2(t1), it means that the current heat supply is greater than the demand, but the heat supply within a future period of time is less than the demand. The PID control opens the heat storage valve of the heat storage tank, but the feed-forward plays the role of closing the heat storage valve in advance, and the final valve action is determined by the comprehensive action of PID and feed-forward. If T2 - T2s < - T2s1 and H1(t1) > H2(t1), it means that the current heat supply is less than the demand, but the heat supply will be greater than the demand in the future. The PID control opens the heat release valve of the heat storage tank, but the feedforward plays the role of closing the heat release valve in advance. The final valve action is determined by the combination of PID and feedforward. ... T2s2, it means that the heat supply is much greater than the demand, and the output of the air-heating unit needs to be reduced; if T2-T2s<-T2s2, it means that the heat supply is much less than the demand, and the output of the air-heating unit needs to be increased. In the output control process of a wind turbine unit, the process of calculating the feedforward value F2 based on the imbalance relationship and the characteristics of the unit includes: The feedforward value F2 is calculated based on the predicted values ​​of weather temperature W and wind speed S within a future period t2, to calculate the heat consumption H1 (t2) of the heat user and the heat generation H2 (t2) of the wind turbine unit.

3. The control method for a wind power heating unit utilizing waste heat from circulating water in a thermal power plant according to claim 2, characterized in that: Where t2 is time, which is selected based on the thermal inertia of the heating system, for example, 1 / 2 to 2 / 3 of the thermal inertia; Wherein, K3 is the proportional coefficient, which is determined according to the output characteristics of the air-heater unit; （4） The heat absorbed by the air-heated unit from the condenser cooling water is achieved by adjusting the evaporator inlet water flow rate according to the needs of the air-heated unit output and ensuring the stability of the condenser outlet water temperature. （5） （6） The evaporator inlet water flow control adopts closed-loop PID + feedforward control: the controller feedback value is the condenser outlet water temperature T3, the set value is the condenser outlet water temperature set value T3s, and the feedforward value F3 is set according to the output of the air-heater unit and is determined by the characteristics of the air-heater unit. Calculation method of controller feedback value F3:

4. The control method for a wind power heating unit utilizing waste heat from circulating water in a thermal power plant according to claim 3, characterized in that: Where K4 is the proportional coefficient, G is the output of the air-heated unit, COP of the air-heated unit = H2 / G = (G+H3) / G, and H3 is the heat absorbed by the air-heated unit from the condenser cooling water. (1) Assume that the system is initially in equilibrium, the wind turbine is tracking the maximum output, the heat storage tank and heat release valves are closed, the unit's steam extraction and standby boiler are closed, and the actual value T2 of the heat user's return water temperature is equal to the set value T2s. At this time, the system is in equilibrium. （7） (2) Due to external influences, the actual value T2 of the return water temperature of the heat user begins to change. When the deviation between T2 and the set value T2s exceeds the dead zone T2s1, the heat storage tank should be adjusted first to store or release heat:

5. The control method for a wind power generating unit utilizing waste heat from circulating water in a thermal power plant according to any one of claims 1-4, characterized in that: If T2-T2s>T2s1, it means the heat supply is greater than the demand. Open the heat storage valve of the heat storage tank to store the excess heat in the heat storage tank. If T2-T2s<-T2s1, it means the heat supply is less than the demand. Open the heat release valve of the heat storage tank to release the excess heat in the heat storage tank to the heat user. ​ ​ 6. The control method for a wind power generating unit utilizing waste heat from circulating water in a thermal power plant according to any one of claims 1-4, characterized in that: The control process for the unit's extraction steam or standby boiler is as follows: The controller feedback value is the return water temperature of the heat user, T2, and the setpoint is the setpoint value of the return water temperature of the heat user, T2s. If the air-heater unit reaches its maximum capacity, the heat storage tank has zero heat storage, and the deviation between the actual return water temperature of the heat user, T2, and the setpoint value, T2s, exceeds the dead zone, T2s3, the unit's extraction steam or standby boiler is activated to ensure the heat user's needs are met. The control adopts conventional PID closed-loop control, which adjusts according to the deviation between the actual return water temperature of the user, T2, and the setpoint value, T2s.

7. A control system for a wind power heating unit utilizing waste heat from circulating water in a thermal power plant, based on any one of claims 1-5, comprising a thermal power unit, a wind power heating unit, and a heating controller, wherein, The wind power heating unit includes an evaporator, a condenser, a wind turbine, and a screw compressor; the thermal power unit includes a condenser, a cooling tower, an extraction steam boiler and / or a standby boiler, a heat exchanger, heat users, and a thermal storage tank. Its characteristic is that, through a heating controller, based on the input parameters and output signals of the heating controller, a cascade + feedforward control method is used to maintain a stable return water temperature for the heat users, ensuring their needs are met. Specifically, the thermal storage or release control of the thermal storage tank is achieved by controllers PID1 and PID2 in series controlling the thermal storage valve and the release valve Y1. The output control of the wind power unit is achieved by controllers PID3 and PID4 in series controlling the output control valve Y2 of the wind power unit.

8. The control system for a wind power generating unit utilizing waste heat from circulating water in a thermal power plant according to claim 7, characterized in that: The evaporator water inlet flow rate is controlled by PID5 through the evaporator water inlet valve Y3.

9. The control system for a wind power generating unit utilizing waste heat from circulating water in a thermal power plant, as described in claim 7 or 8, is characterized in that: The extraction of steam from the unit or the activation of the standby boiler are achieved through PID6 control Y4.

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