A waste heat recovery control method and system for air source heat pumps based on heat analysis

Abstract

This invention proposes a waste heat recovery control method and system for air source heat pumps based on ΔU analysis. The method includes the following steps: real-time acquisition of unit operating parameters; calculation of the recoverable heat and ΔU value of the three-stage waste heat, as well as the demand heat load and demand ΔU value of each terminal; calculation of the grade matching coefficient, constructing a grade matching joint optimization problem with the objective of maximizing the overall system matching excellence, and solving for the optimal allocation matrix under grade constraints and safe superheat constraints; calculating the target opening degree of each output regulating valve based on the optimal allocation matrix, and directionally delivering waste heat of different grades to the most matched heat-using terminals as needed. This invention eliminates the loss of ineffective high-grade heat utilization, realizes the coordinated recovery and quality-based utilization of waste heat of all grades, and significantly improves the overall energy efficiency of the system.

Description

Technical Field

[0001] This invention relates to the field of air source heat pump technology, and in particular to a waste heat recovery control method and system for air source heat pumps based on heat analysis. Background Technology

[0002] Air source heat pumps, as electrically driven heat energy transfer devices based on the reverse Carnot cycle principle, have been widely used in domestic hot water production, industrial drying, and building heating in cold regions due to their high efficiency, cleanliness, and safety. To meet heating demands in extreme low-temperature environments, ultra-low temperature air source heat pumps typically employ enthalpy-increasing compressors or two-stage compression technology, enabling compressor exhaust temperatures to reach 80℃ to 120℃, and even exceeding 130℃ under some operating conditions. In the actual operation of existing ultra-low temperature air source heat pump systems, the compressor generates multiple streams of waste heat with significant differences in temperature range and energy quality. These mainly include: heat dissipated from the compressor casing to the environment, waste heat carried by the lubricating oil cooling circuit, and superheated sensible heat carried by refrigerant vapor from the compressor exhaust outlet to the condenser inlet. These three streams of waste heat not only exhibit significant temperature gradients but also show significant differences in their energy quality, i.e., the work capacity or usable energy per unit of heat. Among them, the exhaust superheat section is a high-grade heat energy, which has the potential to be used for high-value applications such as driving absorption refrigeration cycles, generating low-pressure steam, or preheating industrial processes; while the compressor casing heat dissipation and lubricating oil waste heat are medium- and low-grade heat energy, which are more suitable for low-grade heat compensation such as water inlet preheating, evaporator antifreeze, or gas injection superheat adjustment.

[0003] However, most currently available waste heat recovery solutions adopt a single-point recovery model, such as recovering only the heat stored in the compressor casing for evaporator defrosting, or only recovering the waste heat from lubricating oil for preheating domestic hot water. These solutions fail to integrate the various types of waste heat with different grades into a unified and coordinated recovery system, resulting in the inefficient use of high-grade waste heat for low-temperature heating tasks that can be accomplished with low-grade waste heat, leading to a waste of energy quality; while a large amount of medium- and low-grade waste heat is directly discharged into the environment due to a lack of suitable application outlets. Although some solutions have achieved a certain degree of quantitative recovery of waste heat, they have not quantified and differentiated the work capacity of waste heat from the perspective of the second law of thermodynamics, nor have they incorporated grade matching into the core logic of the control algorithm, thus failing to maximize the release of waste heat value, resulting in huge irreversible energy losses, and limiting the potential for improving the overall energy efficiency of the system. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention proposes a waste heat recovery control method for air source heat pumps based on t-analysis, comprising a waste heat recovery control system for air source heat pumps based on t-analysis, wherein the system includes a sensor group, a compressor unit, and a dynamic distribution unit; The sensor group refers to a collection of measuring elements distributed at key nodes of the system for real-time acquisition of unit operating parameters; The compressor unit is used to generate refrigerant vapor in a high-temperature, high-pressure, superheated state; The dynamic distribution unit includes multiple input interfaces, multiple output interfaces, and multiple electric regulating valves, mixing tanks, and output regulating valves, used to mix and regulate the temperature of the heat transfer medium and then distribute it to different heat-using terminals.

[0005] Preferably, the compressor unit is a gas-injection enthalpy-increasing compressor or a two-stage compression compressor, and the maximum exhaust temperature under rated operating conditions is not lower than 120°C; the compressor unit is driven by a frequency converter, which is used to convert the input industrial frequency AC power into AC power with adjustable frequency and voltage to control the speed of the compressor unit.

[0006] The method includes the following steps: Step S1: Acquire unit operating parameters in real time through the sensor group; The water supply temperature of the primary waste heat transfer medium Return water temperature and mass flow The supply temperature of the secondary waste heat transfer medium Return water temperature and mass flow The supply temperature of the third-stage waste heat transfer medium Return water temperature and mass flow The temperature of the refrigerant after sensible heat separation in the compressor unit exhaust. ; Discharge pressure of the compressor unit Inlet temperature of each heat-using terminal outlet temperature and traffic j represents the index number of each heat-using terminal; and the ambient temperature. ; The first-stage waste heat transfer medium is a heat transfer medium used to transfer the waste heat in the temperature range of the compressor unit exhaust superheat sensible heat; the second-stage waste heat transfer medium is a heat transfer medium used to transfer the waste heat in the temperature range of the lubricating oil; and the third-stage waste heat transfer medium is a heat transfer medium used to transfer the waste heat in the temperature range of the compressor and / or inverter housing. Step S2: Calculate the recoverable heat of each stage of waste heat based on the collected unit operating parameters. Then, the recoverable heat from each stage of waste heat. By performing coupling correction, the independent recoverable heat of each stage of waste heat is obtained. ; and then through The waste heat values ​​at each stage were calculated. ; in, This indicates the level of waste heat at each level; the recoverable heat at each level... Specifically, this includes: recoverable heat from the first stage of waste heat. The recoverable heat from the second stage of waste heat and the recoverable heat of the third stage waste heat The waste heat values ​​at each stage Specifically, this includes: the heat value of the first-stage waste heat. The value of the second stage waste heat and the value of the third stage waste heat ; Step S3: Calculate the required heat load for each heat-consuming terminal based on the collected unit operating parameters. and the logarithmic average temperature on the demand side And then according to and Calculate the demand value ; Step S4: Based on the calculated waste heat values ​​at each stage and demand value Calculate the grade matching coefficient Then define the decision variables, based on the decision variables and the grade matching coefficient. Constructing a joint optimization problem for taste matching; Step S5: Solve the grade matching optimization problem to obtain the optimal allocation matrix, and calculate the target opening degree of each electric regulating valve and output regulating valve in the dynamic allocation unit based on the optimal allocation matrix; The optimal allocation matrix It is a real number matrix with the i-th level of waste heat as the row index and the j-th heat-using terminal as the column index, and elements... This represents the proportion of the mass flow rate of the heat transfer medium of stage i waste heat allocated to the j-th heat-consuming terminal within the current control cycle; for any row i, it satisfies ; According to the optimal allocation matrix Step S1: Calculate the target mass flow rate of each electric regulating valve and the total target mass flow rate of each output regulating valve based on the unit operating parameters collected. Then, calculate the target flow coefficient of the electric regulating valve and the output regulating valve based on the target mass flow rate / total target mass flow rate, the pressure difference before and after the electric regulating valve / output regulating valve, and the density of the heat transfer medium flowing through the valve. Finally, determine the target opening degree of each electric regulating valve and the output regulating valve based on a preset flow coefficient-opening degree calibration table. S6: Based on the optimal allocation matrix The heat transfer medium carrying waste heat at each level is delivered to each heat-using terminal according to its grade, based on the target opening degree.

[0007] Furthermore, the air source heat pump waste heat recovery control system based on sensible heat analysis also includes a sensible heat separation unit, a three-stage waste heat recovery heat exchange unit, and a central control unit. The sensible heat separation unit is used to physically separate the superheated sensible heat portion of the refrigerant vapor discharged from the compressor unit from the saturated latent heat portion to be released in the main condenser in a thermodynamic sense; the sensible heat separation unit has a refrigerant side and a cooling medium side, the refrigerant side outlet is connected to the inlet of the main condenser, and the cooling medium side outlet is connected to the inlet of the first stage heat exchange module of the three-stage waste heat recovery heat exchange unit.

[0008] The three-stage waste heat recovery heat exchange unit includes a first-stage heat exchange module, a second-stage heat exchange module, and a third-stage heat exchange module that are set up independently of each other. They are used to recover the first-stage waste heat from the superheated sensible heat of the compressor exhaust, the second-stage waste heat from the lubricating oil waste heat, and the third-stage waste heat from the cooling of the compressor and / or inverter housing, respectively.

[0009] The inlet of the first-stage heat exchange module is connected to the cooling medium side outlet of the sensible heat separation unit, and the output port is connected to the dynamic distribution unit. Its designed operating temperature range is the first temperature range. The heat transfer medium side has supply and return water pipelines for receiving and transferring the superheated sensible heat from the compressor exhaust separated by the sensible heat separation unit. The output port of the second-stage heat exchange module is connected to the dynamic distribution unit. Its designed operating temperature range is the second temperature range. The heat transfer medium side has supply and return water pipelines for absorbing lubricating oil waste heat. The output port of the third-stage heat exchange module is connected to the dynamic distribution unit. Its designed operating temperature range is the third temperature range. The heat transfer medium side has supply and return water pipelines for recovering the low-grade heat dissipation from the compressor and / or inverter housing in this section. Thus, waste heat with gradients in temperature and energy grade is recovered by three independent heat exchange modules in a decoupled manner, forming high, medium, and low-grade heat outputs.

[0010] Preferably, the first temperature range is set to 80~120℃; the second temperature range is set to 45~70℃; and the third temperature range is set to 25~45℃.

[0011] The dynamic allocation unit includes multiple input interfaces and multiple output interfaces. Each input interface is connected to the heat transfer medium outlet of the first-stage heat exchange module, the heat transfer medium outlet of the second-stage heat exchange module, and the heat transfer medium outlet of the third-stage heat exchange module, respectively. Each output interface is connected to the heat-using terminals with different grade requirements, respectively, for distributing waste heat of different grades to the corresponding heat-using terminals according to real-time operating conditions.

[0012] The dynamic distribution unit includes multiple electrically operated regulating valves, a mixing tank, and an output regulating valve. The heat-using terminals include at least one high-grade heat-using terminal operating within a first temperature range, one medium-grade heat-using terminal operating within a second temperature range, and one low-grade heat-using terminal operating within a third temperature range. The high-grade heat-using terminal preferentially receives the first-stage waste heat transfer medium from the first-stage heat exchange module, the medium-grade heat-using terminal preferentially receives the second-stage waste heat transfer medium from the second-stage heat exchange module, and the low-grade heat-using terminal preferentially receives the third-stage waste heat transfer medium from the third-stage heat exchange module. The dynamic distribution unit, through each electrically operated regulating valve and each output regulating valve, mixes and adjusts the temperature of the heat transfer medium drawn from the three-stage waste heat recovery heat exchange unit before distributing it to different heat-using terminals.

[0013] The heat transfer medium refers to the fluid working medium that circulates in each supply and return water pipeline and is used to absorb and transfer heat.

[0014] The central control unit is electrically connected to the sensor groups set in the compressor unit, sensible heat separation unit, three-stage waste heat recovery heat exchange unit and dynamic distribution unit.

[0015] Furthermore, the recoverable heat from each stage of waste heat The calculation formula is: ; in, Specific heat capacity at constant pressure of the heat transfer medium; The preset sampling control cycle duration for the central control unit; Calculate the logarithmic average temperature of each stage of waste heat during the heat release process. The general formula is: ; The calculation method for the coupling correction is as follows: ; in, The influence coefficient of the unit heat output of the i-th stage heat exchange module on the recoverable heat of the k-th stage heat exchange module is obtained from the system calibration experiment and pre-set in the central control unit; The recoverable heat is the waste heat of the kth stage; The recoverable heat of the k-th stage waste heat under the calibration reference conditions, that is, under the reference conditions set in the system calibration experiment, according to... The recoverable heat of the k-th stage waste heat is obtained using the same calculation formula; and according to Calculate the value of the first stage waste heat. The value of the second stage waste heat and the value of the third stage waste heat ,in , where is the ambient reference temperature, and the unit is Kelvin.

[0016] Furthermore, the required value is calculated using the following formula. : ; ; .

[0017] Furthermore, the decision variable is , which represents the proportion of waste heat from each stage that is allocated to the j-th heat-using terminal; The specific joint optimization problem of quality matching is: to maximize the overall matching goodness of the system. Let N be the objective function, where N is the total number of heating terminals and the grade matching coefficient is 1. The calculation formula is: ; ; This is the preset minimum heat transfer difference.

[0018] Furthermore, the optimization process must simultaneously satisfy the following constraints: (1) For each level i, the following condition is satisfied: ; (2) If Then forced ; (3) Refrigerant superheat at the main condenser inlet It must not be lower than the preset minimum safe superheat. ;in, It is determined by the central control unit based on the built-in preset characteristic table and the real-time measured exhaust pressure. The calculated corresponding saturation temperature.

[0019] Introducing safety constraints can proactively prevent excessive exhaust pressure or condensation pressure fluctuations caused by excessive extraction of sensible heat while tapping the waste heat potential, thus ensuring the long-term reliability of the system.

[0020] Furthermore, before solving the grade matching optimization problem in step S5, the following heat-using terminal status sensing and control steps are also performed: Real-time monitoring of the on / off status or demanded heat load of each heat-consuming terminal. When the demand heat load of a certain heat-using terminal j is monitored The load remains below the preset minimum threshold. If the time exceeds the preset duration, it is determined that the heating terminal j has entered the off state. At this time, the heating terminal j is removed from all candidate heating terminals in the grade matching optimization problem, and all decision variables corresponding to the heating terminal j are forced to close. It is zero; When the heat load demand of the heat-using terminal j is monitored Restored to a value greater than the minimum load threshold When this happens, the heating terminal j is added back to the list of candidate heating terminals.

[0021] Furthermore, the specific execution process of step S6 is as follows: The target opening degree of each electric regulating valve and output regulating valve is converted into a corresponding control signal and sent to the actuator of each valve. Each electrically operated regulating valve is driven by the received control signal to move its valve core to the target opening position, so that the heat transfer medium from the first-stage waste heat, the second-stage waste heat, and the third-stage waste heat is distributed according to the flow ratio determined by the optimal distribution matrix. The mixture enters the mixing tank and is mixed to form hot water that meets the requirements of the application's heat terminal; Each output regulating valve drives its valve core to the target opening position according to the received control signal, independently adjusting the total flow rate of the heat transfer medium delivered from the mixing tank to the application heat terminal, so that the heat delivered to the heat terminal matches its current heat load requirement.

[0022] Furthermore, the system also includes a main condenser, an expansion valve, an evaporator, and a gas-liquid separator; the inlet of the main condenser is connected to the refrigerant-side outlet of the sensible heat separation unit, and the outlet is connected to the inlet of the expansion valve; the main condenser is used to condense the refrigerant vapor that has entered the saturated latent heat portion after the superheated sensible heat has been separated by the sensible heat separation unit into liquid refrigerant under constant pressure conditions, thus completing the condensation and heat release process of the heat pump's main heating cycle; The inlet of the expansion valve is connected to the outlet of the main condenser, and the outlet is connected to the inlet of the evaporator; the expansion valve is used to throttle and reduce the pressure of the liquid refrigerant from the main condenser, so that it is converted into a low-temperature and low-pressure gas-liquid two-phase mixture before entering the evaporator; The outlet of the evaporator is connected to the inlet of the gas-liquid separator; the evaporator is used to allow the low-temperature and low-pressure gas-liquid two-phase mixture after being throttled by the expansion valve to absorb heat from the ambient air in the tube and evaporate into a gaseous state, thereby obtaining the initial evaporation refrigerant and completing the evaporation heat absorption process of the heat pump main heating cycle. The inlet of the gas-liquid separator is connected to the outlet of the evaporator, and the outlet is connected to the suction port of the compressor unit. The gas-liquid separator is used to further separate the gas and liquid of the initially evaporated refrigerant returning from the evaporator, ensuring that only gaseous refrigerant enters the compressor unit and preventing compressor liquid slugging damage caused by liquid return.

[0023] Furthermore, the system also includes control logic, which includes: Step A: After the system starts, the evaporator drives the outdoor ambient air to undergo forced convection heat exchange. The low-temperature, low-pressure gas-liquid two-phase mixture absorbs low-grade heat energy from the air in the evaporator, undergoing a boiling phase change into a low-temperature, low-pressure gaseous refrigerant. After absorbing air energy, the gaseous refrigerant passes through a gas-liquid separator to separate residual droplets, and is then drawn into the compressor unit and compressed into a high-temperature, high-pressure superheated refrigerant vapor. The high-temperature, high-pressure superheated refrigerant vapor is discharged from the exhaust port of the compressor unit and enters the sensible heat separation unit. The sensible heat separation unit separates the superheated sensible heat and saturated latent heat in the refrigerant vapor: the separated superheated sensible heat is transferred to the first-stage heat exchange module in the three-stage waste heat recovery heat exchange unit through the cooling medium side outlet; the remaining saturated latent heat after separation enters the main condenser through the refrigerant side outlet, condensing the refrigerant vapor of the saturated latent heat part into liquid refrigerant, and then becoming a low-temperature, low-pressure gas-liquid two-phase mixture after passing through the expansion valve for throttling and pressure reduction, and then re-entering the evaporator to absorb air energy to complete the main heating cycle of the heat pump; Meanwhile, the second-stage heat exchange module recovers the waste heat of the lubricating oil, the third-stage heat exchange module recovers the heat dissipation of the compressor and / or inverter housing, and the three-stage waste heat recovery unit heats the heat transfer medium in each supply and return water pipeline. Step B: The heat transfer medium enters the dynamic distribution unit, and the central control unit runs the air source heat pump waste heat recovery control method based on the analysis to obtain the target opening degree of each electric regulating valve and each output regulating valve according to the current unit operating parameters. Step C: The central control unit outputs control signals to the dynamic distribution unit according to the target opening degree of each electric regulating valve and the output regulating valve. In the dynamic distribution unit, each output regulating valve drives the valve core to move to the target opening position according to the received control signal, and the heat transfer medium drawn from the three-stage waste heat recovery heat exchange unit is delivered and distributed to the corresponding most matched heat-using terminal according to the flow distribution ratio. Step D: Repeat steps B to C at set time intervals to achieve real-time dynamic optimization of system waste heat distribution.

[0024] The beneficial effects of the waste heat recovery control method and system of air source heat pump based on heat analysis are as follows: (1) By physically separating the high-grade exhaust superheat sensible heat from the main condensation process, the high-grade heat energy can be independently extracted and used specifically to drive the high-grade terminal. At the algorithm level, the matching degree of each allocation path is quantitatively evaluated by the grade matching coefficient to ensure that the path with the closer the grade and the smaller the temperature difference is given priority for allocation, thereby solving the problem of downgrading and utilizing high-grade heat energy and greatly reducing heat loss; (2) The original wasted compressor casing heat dissipation and lubricating oil waste heat are included in the recovery system, realizing full grade coverage and maximum recovery of waste heat resources in terms of quantity; (3) Based on the maximization of heat efficiency The optimization algorithm enables optimal matching between multiple waste heats of different grades and multiple heat-using terminals with different grade requirements, avoiding misuse of energy and further improving the system efficiency; (4) The recoverable heat of each waste heat level is coupled and corrected to avoid the overestimation problem that may occur when the heat of each level is directly added together, so that the input parameters truly reflect the actual independently recoverable heat of the system, ensuring the scientificity and accuracy of the allocation scheme; (5) The main cycle safety constraint is introduced in the optimization solution process, and a protection strategy is established for the compressor while deeply exploring the potential of waste heat, effectively eliminating the risk of excessive exhaust pressure and system instability caused by improper heat extraction, and ensuring the reliability of the system's long-term operation. Attached Figure Description

[0025] Figure 1 This is a structural block diagram of an air source heat pump waste heat recovery control system based on t-analysis according to the present invention.

[0026] Figure 2 This is a flowchart illustrating the working control of an air source heat pump waste heat recovery control system based on φ analysis according to the present invention. Figure 3 This is a flowchart of a waste heat recovery control method for air source heat pumps based on heat analysis according to the present invention. Detailed Implementation

[0027] To provide a further understanding of the purpose, structure, features, and functions of the present invention, detailed descriptions are provided below with reference to specific embodiments.

[0028] Example: Figure 1 As shown, this invention proposes an air source heat pump waste heat recovery control system based on sensible heat analysis, including a sensor group, a compressor unit, a sensible heat separation unit, a three-stage waste heat recovery unit, a dynamic distribution unit, and a central control unit.

[0029] The compressor unit uses a gas-injection enthalpy-increasing scroll compressor, which can achieve an exhaust temperature of 120℃ under rated operating conditions at an ambient temperature of -20℃. The exhaust port of the compressor unit is connected to the refrigerant-side inlet of the sensible heat separation unit via an exhaust pipe.

[0030] The sensible heat separation unit is a brazed plate heat exchanger used to physically separate the superheated sensible heat portion of the refrigerant vapor discharged from the compressor unit from the saturated latent heat portion to be released in the main condenser in a thermodynamic sense. The sensible heat separation unit has a refrigerant side and a cooling medium side. The refrigerant side outlet is connected to the inlet of the main condenser, and the cooling medium side outlet is connected to the inlet of the first-stage heat exchange module of the three-stage waste heat recovery heat exchange unit. This avoids the loss of high-grade superheated sensible heat being downgraded to low-grade heat in the main condenser, allowing high-grade thermal energy to be specifically used for high-grade heat-consuming terminals, achieving high-quality and high-efficiency utilization.

[0031] Furthermore, the sensible heat separation unit is equipped with a heat exchange structure that allows the refrigerant and the heat transfer medium to exchange heat in a non-contact manner. By adjusting the flow rate of the heat transfer medium flowing through the heat exchange structure, the refrigerant vapor entering the main condenser is made to be vapor with only a small amount of superheat or in a saturated state, thereby maintaining the stability of the main condenser inlet state while extracting high-grade sensible heat.

[0032] Furthermore, the system also includes a main condenser, an expansion valve, an evaporator, and a gas-liquid separator. The main condenser is a wall-mounted heat exchanger, with its inlet connected to the refrigerant-side outlet of the sensible heat separation unit and its outlet connected to the inlet of the expansion valve. Under constant pressure conditions, the main condenser condenses the vapor with only a trace of superheat or in a saturated state, which has undergone superheat separation by the sensible heat separation unit, into liquid refrigerant, completing the condensation heat release process of the heat pump's main heating cycle. During the condensation heat release process, since the superheated sensible heat portion of the refrigerant vapor entering the main condenser has been significantly eliminated by the sensible heat separation unit, the average temperature difference of heat transfer inside the main condenser is more uniform. The inlet of the expansion valve is connected to the outlet of the main condenser, and the outlet is connected to the inlet of the evaporator; the expansion valve is used to throttle and reduce the pressure of the liquid refrigerant from the main condenser, so that it is converted into a low-temperature and low-pressure gas-liquid two-phase mixture before entering the evaporator; The evaporator is a finned tube heat exchanger, and its outlet is connected to the inlet of the gas-liquid separator. The evaporator is used to allow the low-temperature and low-pressure gas-liquid two-phase mixture after being throttled by the expansion valve to absorb heat from the ambient air in the tube and evaporate into a gaseous state, thereby obtaining the initial evaporation refrigerant and completing the evaporation heat absorption process of the main heating cycle of the heat pump. The inlet of the gas-liquid separator is connected to the outlet of the evaporator, and the outlet is connected to the suction port of the compressor unit. The gas-liquid separator is used to further separate the gas and liquid of the initially evaporated refrigerant returning from the evaporator, ensuring that only gaseous refrigerant enters the compressor unit and preventing compressor liquid slugging damage caused by liquid return.

[0033] The compressor unit, sensible heat separation unit, main condenser, expansion valve, evaporator, and gas-liquid separator mentioned above are connected end to end through refrigerant pipelines to form a complete heat pump main heating cycle loop. In the heat pump main heating cycle loop, the sensible heat separation unit is connected in series between the compressor exhaust port and the main condenser inlet. The superheated sensible heat in the refrigerant vapor has been separated and guided to the first heat exchange module of the three-stage waste heat recovery heat exchange unit before entering the main condenser. The refrigerant vapor only needs to complete the condensation phase change process to a near-pure saturation state in the main condenser. Therefore, the heat exchange area of ​​the main condenser can be more fully utilized for condensation phase change heat transfer rather than simply cooling superheated steam, thus improving the heat exchange efficiency of the main condenser. At the same time, the three-stage waste heat recovery heat exchange unit integrates the heat dissipation of the compressor and / or inverter housing, lubricating oil waste heat, and superheated sensible heat in the separated refrigerant vapor into a tiered recovery and utilization system. This allows multiple streams of waste heat that were originally discarded or inefficiently utilized to be matched to different heat-using terminals according to their grade, ultimately achieving the synergistic beneficial effect of efficient operation of the main heating cycle and maximum recovery of all grades of waste heat.

[0034] The three-stage waste heat recovery heat exchange unit specifically includes: The first-stage heat exchange module has its outlet connected to the first input port of the dynamic distribution unit. Its designed operating temperature range is 80~120℃. It is used to receive and transfer the superheated sensible heat of the compressor exhaust separated from the sensible heat separation unit. The second-stage heat exchange module is a shell-and-tube oil cooler connected in series in the compressor lubricating oil circuit. Its water-side outlet is connected to the second input port of the dynamic distribution unit. The designed operating temperature range is 45~70℃, and it is used to absorb waste heat from the lubricating oil. The third-stage heat exchange module consists of a serpentine water-cooled coil welded to the surface of the compressor housing and a water-cooled plate attached to the inverter's heat dissipation backplate. Its outlet is connected to the third input port of the dynamic distribution unit. The designed operating temperature range is 25~45℃. It is used to recover the low-grade heat dissipation of the compressor and / or inverter housing in this part.

[0035] Three streams of waste heat of different grades are decoupled and independently recovered, forming three heat transfer medium outputs with clear high, medium and low temperature grades. This incorporates all the previously wasted medium and low grade waste heat into the recovery system, achieving full grade coverage and maximum quantity recovery of waste heat resources.

[0036] In the dynamic distribution unit, each heat-using terminal j corresponds to a mixing tank. Each mixing tank has three electrically operated regulating valves at its inlet, connected to the heat transfer medium outlets of the first, second, and third stage heat exchange modules, respectively. These valves receive commands from the central control unit and independently adjust the flow distribution ratio of the heat transfer medium entering each mixing tank from the first, second, and third stage heat exchange modules, thereby distributing hot water at the target temperature that meets the grade requirements of the corresponding terminal within each mixing tank. The output regulating valves are respectively located between the output port of each mixing tank and each heat-using terminal. They receive opening commands from the central control unit and independently adjust the total flow rate of the heat transfer medium delivered from each mixing tank to each heat-using terminal, ensuring that the heat received by each terminal matches its current demand load. Ultimately, this achieves efficient and directional delivery of multi-grade waste heat to multi-grade heat-using terminals, avoiding energy mismatch.

[0037] In this embodiment, the heating terminal includes: As a low-pressure steam generator used in high-grade heat terminals, the temperature of the input hot water must not be lower than 95°C. ; As a preheating coil for domestic hot water tanks used in medium-grade heat terminals, the temperature of the input hot water is required to be 55°C. Up to 65 between; As a low-grade heat terminal, the low-temperature floor radiant heating manifold requires a supply water temperature of approximately 40°C. .

[0038] The central control unit has a built-in programmable logic controller and is electrically connected to the sensor groups set in the compressor unit, sensible heat separation unit, three-stage waste heat recovery heat exchange unit and dynamic distribution unit.

[0039] like Figure 2 As shown, the control logic of the system includes the following steps: Step A: After the system starts, the evaporator drives the outdoor ambient air to undergo forced convection heat exchange. The low-temperature, low-pressure gas-liquid two-phase mixture absorbs low-grade heat energy from the air in the evaporator, undergoing a boiling phase change into a low-temperature, low-pressure gaseous refrigerant. After absorbing air energy, the gaseous refrigerant passes through a gas-liquid separator to separate residual droplets, and is then drawn into the compressor unit and compressed into a high-temperature, high-pressure superheated refrigerant vapor. The high-temperature, high-pressure superheated refrigerant vapor is discharged from the exhaust port of the compressor unit and enters the sensible heat separation unit. The sensible heat separation unit separates the superheated sensible heat and saturated latent heat in the refrigerant vapor: the separated superheated sensible heat is transferred to the first-stage heat exchange module in the three-stage waste heat recovery heat exchange unit through the cooling medium side outlet; the remaining saturated latent heat after separation enters the main condenser through the refrigerant side outlet, condensing the refrigerant vapor of the saturated latent heat part into liquid refrigerant, and then becoming a low-temperature, low-pressure gas-liquid two-phase mixture after passing through the expansion valve for throttling and pressure reduction, and then re-entering the evaporator to absorb air energy to complete the main heating cycle of the heat pump; Meanwhile, the second-stage heat exchange module recovers the waste heat of the lubricating oil, the third-stage heat exchange module recovers the heat dissipation of the compressor and / or inverter housing, and the three-stage waste heat recovery unit heats the heat transfer medium in each supply and return water pipeline. Step B: The heat transfer medium enters the dynamic distribution unit, and the central control unit runs the air source heat pump waste heat recovery control method based on the analysis to obtain the target opening degree of each electric regulating valve and each output regulating valve according to the current unit operating parameters. Step C: The central control unit outputs control signals to the dynamic distribution unit according to the target opening degree of each electric regulating valve and the output regulating valve. In the dynamic distribution unit, each output regulating valve drives the valve core to move to the target opening position according to the received control signal, and the heat transfer medium drawn from the three-stage waste heat recovery heat exchange unit is delivered and distributed to the corresponding most matched heat-using terminal according to the flow distribution ratio. Step D: Repeat steps B to C at set time intervals to achieve real-time dynamic optimization of system waste heat distribution.

[0040] like Figure 3 As shown, this invention proposes a waste heat recovery control method for air source heat pumps based on heat analysis, comprising the following steps: Step S1: Acquire unit operating parameters in real time through the sensor group; The sensor group refers to a collection of measuring elements distributed at key nodes of the system, used to convert physical state quantities into electrical signals that can be recognized by the central control unit; The real-time acquisition of unit operating parameters through the sensor array specifically includes: The supply water temperature of the first-stage waste heat transfer medium is obtained by a temperature sensor installed at the outlet of the first-stage heat exchange module. The unit is degrees Celsius, and the first-stage return water temperature is obtained from the temperature sensor installed at the return water inlet of the first-stage heat exchange module. The unit is degrees Celsius, and the mass flow rate of the first-stage waste heat transfer medium is obtained from the flow meter installed on the outlet water pipeline of the first-stage heat exchange module. The unit is kg / s; The supply water temperature of the secondary waste heat transfer medium is obtained by a temperature sensor installed at the outlet of the secondary heat exchange module. The unit is degrees Celsius, and it refers to the second-stage return water temperature obtained from a temperature sensor installed at the return water inlet of the second-stage heat exchange module. The unit is degrees Celsius, and the mass flow rate of the second-stage waste heat transfer medium is obtained from the flow meter installed on the outlet water pipeline of the second-stage heat exchange module. The unit is kg / s; The supply water temperature of the third-stage waste heat transfer medium is obtained by a temperature sensor installed at the outlet of the third-stage heat exchange module. The unit is degrees Celsius, and the temperature of the third-stage return water is obtained from the temperature sensor installed at the return water inlet of the third-stage heat exchange module. The unit is degrees Celsius, and the mass flow rate of the third-stage waste heat transfer medium is obtained from the flow meter installed on the outlet water pipeline of the third-stage heat exchange module. The unit is kg / s; The temperature of the refrigerant after sensible heat separation in the compressor unit exhaust is obtained from the temperature sensor installed on the refrigerant outlet pipe of the sensible heat separation unit. The unit is degrees Celsius, which represents the temperature of the refrigerant vapor that is about to enter the main condenser after being cooled by heat exchange in the sensible heat separation unit. The discharge pressure of the compressor unit is obtained from a pressure sensor installed in the compressor discharge line. The unit is kPa; The inlet temperature of each heat-consuming terminal is obtained by temperature sensors and flow meters installed on the inlet and outlet pipes of each heat-consuming terminal. outlet temperature (Unit: degrees Celsius) and the mass flow rate of the heat transfer medium at each heat-using terminal. The unit is kg / s; And the ambient temperature obtained by an outdoor ambient temperature sensor. The unit is Celsius.

[0041] Step S2: Calculate the recoverable heat of each stage of waste heat based on the collected unit operating parameters. Then, the recoverable heat from each stage of waste heat. By performing coupling correction, the independent recoverable heat of each stage of waste heat is obtained. ; and then through The waste heat values ​​at each stage were calculated. ; in, The recoverable heat of the waste heat at each stage Specifically, this includes: recoverable heat from the first stage of waste heat. The recoverable heat from the second stage of waste heat and the recoverable heat of the third stage waste heat The waste heat values ​​at each stage Specifically, this includes: the heat value of the first-stage waste heat. The value of the second stage waste heat and the value of the third stage waste heat .

[0042] The calculation formula is: ; in, Let be the specific heat capacity at constant pressure of the heat transfer medium, and be a known physical property constant. The preset sampling control cycle duration for the central control unit, in seconds; Calculate the logarithmic average temperature of each stage of waste heat during the heat release process. The general formula is: ; The calculation method for the coupling correction is as follows: ; in, The influence coefficient of the unit heat output of the i-th stage heat exchange module on the recoverable heat of the k-th stage heat exchange module is obtained from the system calibration experiment and pre-set in the central control unit; its physical meaning is: when the heat output of the k-th stage heat exchange module is relative to its reference value... For every unit change, the recoverable heat of the i-th stage waste heat... The number of units that change accordingly; The recoverable heat of the k-th stage waste heat has the same meaning as... They are exactly the same. k is used to traverse other waste heat levels except for the current i-th level waste heat. That is, when performing coupling correction on the first level waste heat (i=H), k takes M and L in turn, representing the recoverable heat of the second and third level waste heat, respectively; when performing coupling correction on the second level (i=M), k takes H and L in turn; and so on.

[0043] The recoverable heat of the k-th stage waste heat under the calibration reference conditions, that is, under the reference conditions set in the system calibration experiment, according to... The recoverable heat of the k-th stage waste heat obtained by the same calculation formula will not change with the operating conditions after the system calibration is completed; Let be the independent recoverable heat of the i-th stage waste heat after coupling correction. It represents the actual independently recoverable heat of the i-th stage waste heat under the current operating conditions, after considering the marginal impact of heat extraction from other stages on the recoverable heat of this stage.

[0044] and according to Calculate the value of the first stage waste heat. The value of the second stage waste heat and the value of the third stage waste heat ,in , is the ambient reference temperature, in Kelvin (K); The physical meaning of coupling correction is: when the heat taken at a certain stage deviates from the benchmark value, the marginal change caused by this is deducted or compensated from the recoverable heat of other stages, so as to avoid the "artificial increase" problem caused by the direct addition of heat at each stage.

[0045] Based on the supply and return water temperature difference and measured mass flow rate, the recoverable heat of each stage of waste heat is calculated, and then the residual heat value of each stage is calculated using the logarithmic average temperature and Carnot factor. This quantifies the quantity and work capacity of the waste heat, providing a scientific thermodynamic basis for subsequent grade matching.

[0046] Step S3: Calculate the required heat load for each heat-consuming terminal based on the collected unit operating parameters. and the logarithmic average temperature on the demand side And then according to and Calculate the demand value ; The calculation formula is: ; ; ; The required heat load and demand value of each heat-using terminal are calculated using the same method as in step S2, ensuring that the evaluation scale is consistent between the supply side and the demand side. This allows the heat demand of heat-using terminals of different grades to be compared and matched within the same thermodynamic framework, avoiding allocation deviations caused by inconsistent evaluation standards.

[0047] Step S4: Based on the calculated waste heat values ​​at each stage and demand value Calculate the grade matching coefficient Then define the decision variables, based on the decision variables and the grade matching coefficient. Constructing a joint optimization problem for taste matching; The decision variables are , represents the flow distribution ratio of the i-th stage waste heat to the j-th heat-using terminal; The specific joint optimization problem of quality matching is: to maximize the overall matching goodness of the system. Let N be the objective function, where N is the total number of heating terminals and the grade matching coefficient is 1. The calculation formula is: ; ; To preset the minimum heat transfer difference, 3K is used in this embodiment.

[0048] This reflects the degree of ideal matching between supply and demand. This is a correction term for the relative loss of available energy caused by the finite heat transfer temperature difference; the larger the temperature difference, the greater the irreversible loss of the matching path. A normalization correction factor is introduced into the grade matching coefficient. This effectively suppresses sorting biases when there is a significant difference in the magnitude of supply and demand, ensuring that high-grade waste heat is always prioritized for allocation to high-grade terminals during subsequent greedy allocation.

[0049] Furthermore, the optimization process must simultaneously satisfy the following constraints: (1) For each level i, ; (2) Matching is permitted only when the supply temperature is higher than the demand temperature and a minimum heat transfer temperature difference is maintained. Then forced ; (3) Superheat of refrigerant at the main condenser inlet It must not be lower than the minimum safe superheat. , Set to 3℃.

[0050] in, It is determined by the central control unit based on the built-in preset characteristic table and the real-time measured exhaust pressure. The corresponding saturation temperature is calculated, and the specific calculation process is as follows: The central control unit pre-stores a table of the saturation temperature-pressure characteristics of the refrigerant used in the system. This table is indexed by the discharge pressure value and corresponding to the saturation temperature. This is a discrete data table of output values. The data comes from publicly available values ​​of the refrigerant in authoritative physical property databases such as ASHRAE standards or NISTREFPROP, covering the entire possible operating pressure range of the system, with pressure intervals between adjacent data points not exceeding 0.1 MPa. During each control cycle, the central control unit performs the following operations: First, read the discharge pressure of the compressor unit obtained by the pressure sensor installed in the compressor discharge line. Next, find the value in the preset saturation temperature-pressure characteristic table. The two nearest pressure nodes and ,satisfy And obtain the corresponding saturation temperature value. and Finally, linear interpolation was used to calculate the current exhaust pressure. The corresponding saturation temperature ,Right now .

[0051] Constraints are introduced to ensure that the allocation scheme, while pursuing maximum energy efficiency, does not violate basic physical limitations and operational safety requirements.

[0052] Step S5: Solve the grade matching optimization problem to obtain the optimal allocation matrix, and calculate the target opening degree of each electric regulating valve and output regulating valve in the dynamic allocation unit based on the optimal allocation matrix.

[0053] This step employs a priority-based greedy allocation strategy and includes the following sub-steps: S51: Filter feasible pairs and sort them to obtain a priority allocation queue; For each pair of waste heat supply stages i ( For each heat terminal j (j=1,2,...,N), perform the following judgment: like If the pairing is deemed feasible, it will be included in the candidate set. And calculate the grade matching coefficient of the pair. As a priority weight for allocation.

[0054] candidate set All feasible pairings are ranked according to their grade matching coefficient. The values ​​are arranged in descending order to form a priority allocation queue, and the feasible pair with the larger the quality matching coefficient is, the higher the priority to be allocated.

[0055] Furthermore, during each control cycle, the central control unit also checks the on / off status of each heat-consuming terminal or the actual measured heat load demand. When the demand heat load of a certain heat terminal If the load remains below the minimum load threshold for an extended period of time, the heating terminal is determined to be shut down and removed from the candidate set for optimization. Remove it from the heat supply chain so that the heat-using terminal does not participate in subsequent waste heat distribution. When the heat demand load of the heat-using terminal is monitored... When the load recovers to a level greater than the minimum load threshold, the heating terminal will be automatically re-added to the candidate set. .

[0056] S52: The upper limit of distributable heat of the first-stage waste heat under the approved safety constraints; Based on the refrigerant superheat at the main condenser inlet With the lower limit of safe overheating The relationship determines the upper limit of distributable heat of the first-stage waste heat within the current control cycle. Specifically: like ,but ; like ,but

[0057] like ,but =0.

[0058] In this embodiment, a lower limit for safe overheating is set. and early warning margin ; The second and third stage waste heat are not affected by the above constraints, and the upper limit of the allocable heat is set as calculated in step S2. and .

[0059] S53: Allocate queues according to priority, assign each feasible pair, and obtain the optimal allocation matrix; Initialize the remaining distributable heat of each stage of waste heat This includes the remaining distributable heat from the first stage of waste heat. The remaining distributable heat of the second stage waste heat and the remaining distributable heat of the third stage waste heat Specifically: , , .

[0060] Initialize the remaining heat demand of each heat-using terminal j : ,in Let be the rated maximum receiving power of terminal j.

[0061] Allocate queues according to the priority determined in sub-step S51, and retrieve each feasible pairing in turn. Perform the following allocation operation: Determine the feasible pair (i,j) and the available allocation amount for this time. ; Calculate the flow allocation ratio for feasible pairings (i,j) ; Update parameters, i.e. , ; If the remaining distributable heat of a certain level of waste heat Zero or the remaining heat demand of a certain heat-using terminal If the value is zero, then skip all subsequent pairings in the priority allocation queue that involve waste heat of that level or that heat-using terminal.

[0062] After the priority allocation queue is processed, the complete optimal allocation matrix is ​​obtained. ; Unassigned feasible pairings are maintained .

[0063] S54: Calculate the target mass flow rate and the total target mass flow rate based on the optimal allocation matrix; For each stage i and each heat-consuming terminal j, the target mass flow rate of the heat transfer medium in the pipeline from the heat exchange module i to the heat-consuming terminal j. for: ; in The mass flow rate of the i-th stage heat transfer medium obtained by the flow meter in step S1 is denoted as .

[0064] The specification defines the mass flow rate of the heat transfer medium from each stage of waste heat recovery heat exchange module to each heat-using terminal. This serves as the direct basis for calculating the opening degree of the electric regulating valve, allowing the actual flow rate to reach the specified value by controlling the electric regulating valve. This ensures that the mixing ratio of different grades of heat transfer media entering the corresponding mixing tanks of each heat-using terminal meets the grade matching requirements.

[0065] The total target mass flow rate of the heat transfer medium entering the j-th heat-consuming terminal is obtained by summing the target mass flow rates of each heat transfer medium. ,Right now = .

[0066] For heat terminal j, the various heat transfer media are fully mixed in the mixing tank of the dynamic distribution unit, and the theoretical supply water temperature after mixing is... Calculate using the following formula: ; Central control unit verification Check whether the minimum allowable inlet water temperature is not lower than that of the heat-using terminal j. If not, adjust the mixing ratio or supplement with other waste heat stages.

[0067] S55: Calculate the opening degree of the electric control valve and the output control valve based on the target mass flow rate and the total target mass flow rate; For each electrically operated regulating valve and output regulating valve in the dynamic distribution unit, pressure sensors are also installed on their inlet and outlet pipelines to measure the pressure difference before and after the valve. ; According to the pipeline corresponding to the electric regulating valve k , and fluid density Calculate the required flow coefficient for the electric regulating valve. : ; According to the pipeline corresponding to the output regulating valve K , and fluid density 2. Calculate the required flow coefficient for the output regulating valve. : ; Temperature sensors are installed on the inlet pipes of the electric regulating valve and the output regulating valve to measure the temperature of the heat transfer medium flowing through the valve, in degrees Celsius; fluid density. , These are the densities of the heat transfer medium at the temperatures of the heat transfer medium flowing through the electric regulating valve and the output regulating valve, respectively. These densities are obtained by interpolation from the heat transfer medium temperature-density characteristic table built into the central control unit.

[0068] The central control unit also has a built-in flow coefficient-opening calibration table for each electric regulating valve and output regulating valve. This table is obtained by the valve manufacturer through actual measurement and calibration before leaving the factory, or by calibration using a standard flow meter during on-site commissioning. It contains several sets of discrete data point pairs, each consisting of a flow coefficient value and a corresponding opening percentage value, covering the opening range of 0% to 100%.

[0069] by , As input, the target opening percentage of the electric control valve and the output control valve are obtained by linear interpolation in the opening characteristic table. and .

[0070] S6: Based on the optimal allocation matrix The heat transfer medium carrying waste heat at each level is delivered to each heat-using terminal according to its grade, based on the target opening degree.

[0071] The central control unit will set the target opening of the electric regulating valve. and the target opening of the output regulating valve These signals are converted into corresponding 4-20mA DC current signals or 0-10V DC voltage signals, where 4mA or 0V corresponds to the valve being fully closed, and 20mA or 10V corresponds to the valve being fully open. The central control unit then sends the control signals to the actuators of each inlet and outlet regulating valve in the dynamic distribution unit.

[0072] After receiving the control signal, the actuators of each electric regulating valve drive the valve core to the corresponding target opening position. At this time, the heat transfer media from the first-stage heat exchange module, the second-stage heat exchange module, and the third-stage heat exchange module enter the mixing tank according to the flow ratio determined by the target opening of their respective electric regulating valves, and the heat transfer media are fully mixed in the mixing tank.

[0073] After receiving the control signal, the actuators of each output regulating valve drive the valve core to the corresponding target opening position, independently controlling the total flow rate of the heat transfer medium delivered from the mixing tank to the heat-using terminal, so that the heat delivered to the heat-using terminal matches its current heat load requirement. Matching.

[0074] After the above two-stage adjustment, the heat transfer medium introduced from the three-stage waste heat recovery heat exchange unit is transported in a directional manner. The heat transfer medium of each stage of waste heat is transported to the most suitable heat-using terminal according to its grade.

[0075] A priority-based greedy allocation strategy is employed to solve the optimization problem, prioritizing the allocation of limited high-grade waste heat to the heat-using terminals with the highest grade matching coefficient, thus maximizing the overall system matching excellence. Furthermore, the solution method is computationally efficient and fast. During the solution process, the upper limit of the available amount in the first stage under constraint adjustment is first verified to ensure that the sensible heat extraction amount will not affect the stable operation of the main loop under any circumstances.

[0076] The present invention has been described in the above-described embodiments; however, these embodiments are merely examples for implementing the present invention. It must be noted that the disclosed embodiments do not limit the scope of the present invention. Conversely, any modifications and refinements made without departing from the spirit and scope of the present invention are within the scope of patent protection of the present invention.

[0077] The contents of this invention not described in detail are existing technologies known to those skilled in the art.

Claims

1. A waste heat recovery control method for air source heat pumps based on heat analysis, characterized in that, The system includes a waste heat recovery control system for an air source heat pump based on heat analysis, the system comprising a sensor group, a compressor unit, and a dynamic distribution unit; The sensor group refers to a collection of measuring elements distributed at key nodes of the system for real-time acquisition of unit operating parameters; The compressor unit is used to generate refrigerant vapor in a high-temperature, high-pressure, superheated state; The dynamic distribution unit includes multiple input interfaces, multiple output interfaces, and multiple electric regulating valves, mixing tanks, and output regulating valves, used to mix and adjust the temperature of the heat transfer medium and then distribute it to different heat-using terminals. The method includes the following steps: Step S1: Acquire unit operating parameters in real time through the sensor group; The water supply temperature of the primary waste heat transfer medium Return water temperature and mass flow ; The supply water temperature of the secondary waste heat transfer medium Return water temperature and mass flow ; The water supply temperature of the third-stage waste heat transfer medium Return water temperature and mass flow ; Refrigerant temperature after sensible heat separation in compressor unit discharge ; Discharge pressure of the compressor unit Inlet temperature of each heat-using terminal outlet temperature and traffic j represents the index number of each heat-using terminal; and the ambient temperature. ; The first-stage waste heat transfer medium is a heat transfer medium used to transfer the waste heat in the temperature range of the compressor unit exhaust superheat sensible heat; the second-stage waste heat transfer medium is a heat transfer medium used to transfer the waste heat in the temperature range of the lubricating oil; and the third-stage waste heat transfer medium is a heat transfer medium used to transfer the waste heat in the temperature range of the compressor and / or inverter housing. Step S2: Calculate the recoverable heat of each stage of waste heat based on the collected unit operating parameters. Then, the recoverable heat from each stage of waste heat. By performing coupling correction, the independent recoverable heat of each stage of waste heat is obtained. ; and then through The waste heat values ​​at each stage were calculated. ; in, This indicates the level of waste heat at each level; the recoverable heat at each level... Specifically, this includes: recoverable heat from the first stage of waste heat. The recoverable heat from the second stage of waste heat and the recoverable heat of the third stage waste heat The waste heat values ​​at each stage Specifically, this includes: the heat value of the first-stage waste heat. The value of the second stage waste heat and the value of the third stage waste heat ; Step S3: Calculate the required heat load for each heat-consuming terminal based on the collected unit operating parameters. and the logarithmic average temperature on the demand side And then according to and Calculate the demand value ; Step S4: Based on the calculated waste heat values ​​at each stage and demand value Calculate the grade matching coefficient Then define the decision variables, based on the decision variables and the grade matching coefficient. Constructing a joint optimization problem for taste matching; Step S5: Solve the grade matching optimization problem to obtain the optimal allocation matrix, and calculate the target opening degree of each electric regulating valve and output regulating valve in the dynamic allocation unit based on the optimal allocation matrix; The optimal allocation matrix It is a real number matrix with the i-th level of waste heat as the row index and the j-th heat-using terminal as the column index, and elements... This represents the proportion of the mass flow rate of the heat transfer medium of stage i waste heat allocated to the j-th heat-consuming terminal within the current control cycle; for any row i, it satisfies ; According to the optimal allocation matrix Step S1: Calculate the target mass flow rate of each electric regulating valve and the total target mass flow rate of each output regulating valve based on the unit operating parameters collected. Then, calculate the target flow coefficient of the electric regulating valve and the output regulating valve based on the target mass flow rate / total target mass flow rate, the pressure difference before and after the electric regulating valve / output regulating valve, and the density of the heat transfer medium flowing through the valve. Finally, determine the target opening degree of each electric regulating valve and the output regulating valve based on a preset flow coefficient-opening degree calibration table. S6: Based on the optimal allocation matrix The heat transfer medium carrying waste heat at each level is delivered to each heat-using terminal according to its grade, based on the target opening degree.

2. The method according to claim 1, characterized in that, The system also includes a sensible heat separation unit, a three-stage waste heat recovery heat exchange unit, and a central control unit; The exhaust port of the compressor unit is connected to the inlet of the sensible heat separation unit; The sensible heat separation unit is used to separate the superheated sensible heat and saturated latent heat in the refrigerant vapor. The sensible heat separation unit has a refrigerant side and a cooling medium side. The refrigerant side outlet is connected to the inlet of the main condenser, and the cooling medium side outlet is connected to the inlet of the first stage heat exchange module of the three-stage waste heat recovery heat exchange unit. The three-stage waste heat recovery heat exchange unit includes a first-stage heat exchange module, a second-stage heat exchange module, and a third-stage heat exchange module arranged independently in sequence. These modules are used to recover the first-stage waste heat (superheated sensible heat from compressor exhaust), the second-stage waste heat (waste heat from lubricating oil), and the third-stage waste heat (heat dissipated from the compressor and / or inverter housing). The inlet of the first-stage heat exchange module is connected to the cooling medium side outlet of the sensible heat separation unit, and its designed operating temperature range is the first temperature range. The heat transfer medium side has supply and return water pipelines for receiving and transferring the superheated sensible heat from the compressor exhaust separated by the sensible heat separation unit. The designed operating temperature range of the second-stage heat exchange module is the second temperature range, and its heat transfer medium side has supply and return water pipelines for absorbing waste heat from the lubricating oil. The designed operating temperature range of the third-stage heat exchange module is the third temperature range, and its heat transfer medium side has supply and return water pipelines for recovering the low-grade heat dissipation from the compressor and / or inverter housing in this section. Each input interface of the dynamic distribution unit is connected to the heat transfer medium outlet of the first-stage heat exchange module, the heat transfer medium outlet of the second-stage heat exchange module, and the heat transfer medium outlet of the third-stage heat exchange module, respectively; each output interface is connected to the heat-using terminals with different quality requirements, respectively; the dynamic distribution unit mixes and adjusts the temperature of the heat transfer medium drawn from the third-stage waste heat recovery heat exchange unit through each electric regulating valve and each output regulating valve, and then distributes it to different heat-using terminals. The central control unit is electrically connected to the compressor unit, the sensible heat separation unit, the three-stage waste heat recovery heat exchange unit and the dynamic distribution unit, respectively. The heat-using terminals include at least one high-grade heat-using terminal operating in a first temperature range, one medium-grade heat-using terminal operating in a second temperature range, and one low-grade heat-using terminal operating in a third temperature range. The high-grade heat-using terminal preferentially receives the first-stage waste heat transfer medium from the first-stage heat exchange module, the medium-grade heat-using terminal preferentially receives the second-stage waste heat transfer medium from the second-stage heat exchange module, and the low-grade heat-using terminal preferentially receives the third-stage waste heat transfer medium from the third-stage heat exchange module.

3. The method according to claim 2, characterized in that, In step S2, the recoverable heat of the waste heat at each stage The calculation formula is: ； in, The specific heat capacity at constant pressure of the heat transfer medium; The preset sampling control cycle duration for the central control unit; Calculate the logarithmic average temperature of each stage of waste heat during the heat release process. The general formula is: ； The calculation method for the coupling correction is as follows: ； in, The influence coefficient of the unit heat output of the i-th stage heat exchange module on the recoverable heat of the k-th stage heat exchange module is obtained from the system calibration experiment and pre-set in the central control unit; The recoverable heat is the waste heat of the kth stage; The recoverable heat of the k-th stage waste heat under the calibration reference conditions, that is, under the reference conditions set in the system calibration experiment, according to... The recoverable heat of the k-th stage waste heat is obtained using the same calculation formula; and according to Calculate the value of the first stage waste heat. The value of the second stage waste heat and the value of the third stage waste heat ,in , where is the ambient reference temperature, and the unit is Kelvin.

4. The method according to claim 1, characterized in that, In step S3, the required value is calculated using the following formula. : ； ； 。 5. The method according to claim 1, characterized in that, In step S4, The decision variables are , which represents the proportion of waste heat from each stage that is allocated to the j-th heat-using terminal; The specific joint optimization problem of quality matching is: to maximize the overall matching goodness of the system. Let N be the objective function, where N is the total number of heating terminals and the grade matching coefficient is 1. The calculation formula is: ； ； This is the preset minimum heat transfer difference.

6. The method according to claim 5, characterized in that, The optimization process must simultaneously satisfy the following constraints: (1) For each level i, the following condition is satisfied: ; (2) If Then forced ; (3) Refrigerant superheat at the main condenser inlet It must not be lower than the preset minimum safe superheat. ;in, It is determined by the central control unit based on the built-in preset characteristic table and the real-time measured exhaust pressure. The calculated corresponding saturation temperature.

7. The method according to claim 5, characterized in that, Before solving the grade matching optimization problem in step S5, the following heat-using terminal status sensing and control steps are also performed: Real-time monitoring of the on / off status or demanded heat load of each heat-consuming terminal. When the demand heat load of a certain heat-using terminal j is monitored The load remains below the preset minimum threshold. If the time exceeds the preset duration, it is determined that the heating terminal j has entered the off state. At this time, the heating terminal j is removed from all candidate heating terminals in the grade matching optimization problem, and all decision variables corresponding to the heating terminal j are forced to close. It is zero; When the heat load demand of the heat-using terminal j is monitored Restored to a value greater than the minimum load threshold When this happens, the heating terminal j is added back to the list of candidate heating terminals.

8. The method according to claim 1, characterized in that, The specific execution process of step S6 is as follows: The target opening degree of each electric regulating valve and output regulating valve is converted into a corresponding control signal and sent to the actuator of each valve. Each electrically operated regulating valve is driven by the received control signal to move its valve core to the target opening position, so that the heat transfer medium from the first-stage waste heat, the second-stage waste heat, and the third-stage waste heat is distributed according to the flow ratio determined by the optimal distribution matrix. The mixture enters the mixing tank and is mixed to form hot water that meets the requirements of the application's heat terminal; Each output regulating valve drives its valve core to the target opening position according to the received control signal, independently adjusting the total flow rate of the heat transfer medium delivered from the mixing tank to the application heat terminal, so that the heat delivered to the heat terminal matches its current heat load requirement.

9. The method according to claim 2, characterized in that, The system also includes a main condenser, an expansion valve, an evaporator, and a gas-liquid separator; the inlet of the main condenser is connected to the refrigerant-side outlet of the sensible heat separation unit, and the outlet is connected to the inlet of the expansion valve; the main condenser is used to condense the refrigerant vapor that has entered the saturated latent heat portion after the superheated sensible heat has been separated by the sensible heat separation unit into liquid refrigerant under constant pressure conditions, thus completing the condensation and heat release process of the main heating cycle of the heat pump; The inlet of the expansion valve is connected to the outlet of the main condenser, and the outlet is connected to the inlet of the evaporator; the expansion valve is used to throttle and reduce the pressure of the liquid refrigerant from the main condenser, so that it is converted into a low-temperature and low-pressure gas-liquid two-phase mixture before entering the evaporator; The outlet of the evaporator is connected to the inlet of the gas-liquid separator; the evaporator is used to allow the low-temperature and low-pressure gas-liquid two-phase mixture after being throttled by the expansion valve to absorb heat from the ambient air in the tube and evaporate into a gaseous state, thereby obtaining the initial evaporation refrigerant and completing the evaporation heat absorption process of the heat pump main heating cycle. The inlet of the gas-liquid separator is connected to the outlet of the evaporator, and the outlet is connected to the suction port of the compressor unit. The gas-liquid separator is used to further separate the gas and liquid of the initially evaporated refrigerant returning from the evaporator, ensuring that only gaseous refrigerant enters the compressor unit and preventing compressor liquid slugging damage caused by liquid return.

10. The method according to claim 9, characterized in that, The system also includes control logic, which includes: Step A: After the system starts, the evaporator drives the outdoor ambient air to undergo forced convection heat exchange. The low-temperature, low-pressure gas-liquid two-phase mixture absorbs low-grade heat energy from the air in the evaporator, undergoing a boiling phase change into a low-temperature, low-pressure gaseous refrigerant. After absorbing air energy, the gaseous refrigerant passes through a gas-liquid separator to separate residual droplets, and is then drawn into the compressor unit and compressed into a high-temperature, high-pressure superheated refrigerant vapor. The high-temperature, high-pressure superheated refrigerant vapor is discharged from the exhaust port of the compressor unit and enters the sensible heat separation unit. The sensible heat separation unit separates the superheated sensible heat and saturated latent heat in the refrigerant vapor: the separated superheated sensible heat is transferred to the first-stage heat exchange module in the three-stage waste heat recovery heat exchange unit through the cooling medium side outlet; the remaining saturated latent heat after separation enters the main condenser through the refrigerant side outlet, condensing the refrigerant vapor of the saturated latent heat part into liquid refrigerant, and then becoming a low-temperature, low-pressure gas-liquid two-phase mixture after passing through the expansion valve for throttling and pressure reduction, and then re-entering the evaporator to absorb air energy to complete the main heating cycle of the heat pump; Meanwhile, the second-stage heat exchange module recovers the waste heat of the lubricating oil, the third-stage heat exchange module recovers the heat dissipation of the compressor and / or inverter housing, and the three-stage waste heat recovery unit heats the heat transfer medium in each supply and return water pipeline. Step B: The heat transfer medium enters the dynamic distribution unit, and the central control unit runs the air source heat pump waste heat recovery control method based on the analysis to obtain the target opening degree of each electric regulating valve and each output regulating valve according to the current unit operating parameters. Step C: The central control unit outputs control signals to the dynamic distribution unit according to the target opening degree of each electric regulating valve and the output regulating valve. In the dynamic distribution unit, each output regulating valve drives the valve core to move to the target opening position according to the received control signal, and the heat transfer medium drawn from the three-stage waste heat recovery heat exchange unit is delivered and distributed to the corresponding most matched heat-using terminal according to the flow distribution ratio. Step D: Repeat steps B to C at set time intervals to achieve real-time dynamic optimization of system waste heat distribution.

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