Heat pump control method and system for tower water heat recovery heating based on digital twinning

Abstract

The invention discloses a heat pump control method and system for tower water heat recovery heating based on digital twinning, a magnetic suspension heat pump absorbs heat from a tower water system and a circulating water side in a production line through an evaporator, and releases heat through a condenser and a plate heat exchanger to heat a water tank; the method further comprises the following steps that a magnetic suspension heat pump unit operates in the waste heat recovery process of the tower water circulation system under the multiple working conditions, and heat of the tower water heat recovery system is transferred within the set temperature range of the tower water temperature rising scheme; operating data of the magnetic suspension heat pump unit are collected in real time, and a dynamic simulation model of synchronous mapping of the magnetic suspension heat pump unit is constructed based on the magnetic suspension heat pump unit structure parameterized model; thermodynamic simulation is carried out on a tower water temperature rise scheme under multiple working conditions based on the heat absorption and heat release processes of the magnetic suspension heat pump by a digital twin model, and the waste heat recovery process of a tower water circulation system is simulated; and by calculating the heat transfer efficiency under different working conditions, the compressor power and the plate exchange parameters are dynamically adjusted and fed back to the magnetic suspension heat pump unit.

Description

Technical Field

[0001] The present invention relates to the technical field of tower water waste heat recovery, and in particular to a heat pump control method and system for tower water heat recovery heating based on digital twin. Background Art

[0002] In traditional technologies, tower water heating mainly relies on direct steam heating or electric heating methods. Its basic principle is to transfer the heat of high-temperature steam to circulating water through a steam heat exchanger to achieve a rise in water temperature. Steam heating requires a large amount of fuel to generate high-temperature steam, with low energy conversion efficiency and heat loss during steam transportation. The temperature control of steam heating depends on manual adjustment of the valve opening. In addition, the electric heating method consumes a huge amount of electric energy and has high operating costs, making it difficult to meet the production requirements of green and low-carbon. In recent years, heat pump technology has gradually been applied to industrial waste heat recovery.

[0003] Existing heat pumps increase the temperature of low-temperature heat sources through compressors. After long-term operation of plate heat exchangers, surface fouling accumulates, resulting in a decrease in the heat transfer coefficient. Moreover, there is a lack of a dynamic correction mechanism, and the energy efficiency gradually deteriorates. Existing systems mostly rely on manual experience to adjust operating parameters and cannot predict the equipment status in real time, leading to maintenance lags and unexpected shutdowns. Summary of the Invention

[0004] In order to overcome the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a heat pump control method for tower water heat recovery heating based on digital twin to solve the problems raised in the above background art.

[0005] The technical solution adopted by the present invention to solve its technical problems is: a heat pump control method for tower water heat recovery heating based on digital twin. The magnetic levitation heat pump absorbs heat from the tower water system and the circulating water side of the production line through an evaporator, and releases heat through a condenser and a plate heat exchanger to heat the water tank. The method further includes the following steps:

[0006] Operating a magnetic levitation heat pump unit during the waste heat recovery process of a multi-condition tower water circulation system, so that the tower water heat recovery system transfers heat within the set temperature range of the tower water temperature increase plan;

[0007] Real-time collecting the operating data of the magnetic levitation heat pump unit, and based on the structural parametric model of the magnetic levitation heat pump unit, constructing a dynamic simulation model that synchronously maps the magnetic levitation heat pump unit;

[0008] Based on the digital twin model, performing thermodynamic simulation on the heat absorption and heat release processes of the magnetic levitation heat pump, and simulating the waste heat recovery process of the tower water circulation system for multi-condition tower water temperature increase plans;

[0009] By calculating the heat transfer efficiency under different conditions, dynamically adjusting the compressor power and plate heat exchanger parameters, and feeding back to the magnetic levitation heat pump unit.

[0010] As a further improvement of the present invention: The magnetic levitation heat pump unit operating in the waste heat recovery process of the tower water circulation system under multiple working conditions includes:

[0011] A magnetic levitation heat pump unit, which has a low-temperature heat absorption side, a high-temperature heat release side, and a magnetic levitation centrifugal compressor. The low-temperature heat absorption side absorbs heat in the evaporator. After the refrigerant absorbs the heat of the tower water system and the circulating water in the production line and evaporates into a refrigerant gas, it does work through the high-temperature magnetic levitation centrifugal compressor, and then releases heat in the condenser through the high-temperature heat release side. The condenser releases the heat of the high-temperature and high-pressure refrigerant gas in a condensing manner.

[0012] The magnetic levitation heat pump unit adjusts the heat released by the condenser through a heating plate heat exchanger, and discharges the heated circulating water into the tower water tank.

[0013] As a further improvement of the present invention: The magnetic levitation heat pump unit operating in the waste heat recovery process of the tower water circulation system under multiple working conditions further includes:

[0014] Winter condition: The evaporator side of the magnetic levitation centrifugal compressor absorbs the first temperature of the circulating water. After using the first temperature of the circulating water to do work through the high-temperature magnetic levitation centrifugal compressor, the condenser compresses the refrigerant gas and releases heat. And by adjusting the heat released by the condenser through a heating plate heat exchanger, the circulating water is heated to the first preset temperature and discharged into the tower water tank, raising the water temperature of the tower water tank.

[0015] Summer condition: The evaporator side of the magnetic levitation centrifugal compressor absorbs the second temperature of the circulating water. After using the second temperature of the circulating water to do work through the high-temperature magnetic levitation centrifugal compressor, the condenser compresses the refrigerant gas and releases heat. And by adjusting the heat released by the condenser through a heating plate heat exchanger, the circulating water is heated to the first preset temperature and discharged into the tower water tank, raising the water temperature of the tower water tank.

[0016] Adjustment condition: The heating plate heat exchanger absorbs the third temperature of the circulating water in the water tank, exchanges heat with the circulating water heated to the first preset temperature, adjusts the circulating water in the heating plate heat exchanger in the water tank to the second preset temperature, and the condenser side of the magnetic levitation centrifugal compressor absorbs the fourth temperature of the circulating water and releases heat after being compressed to the preset temperature.

[0017] As a further improvement of the present invention: The real-time acquisition of the operating data of the magnetic levitation heat pump unit includes:

[0018] The operating data of the magnetic levitation heat pump unit is real-time acquired through sensors. The operating data includes the temperatures of the evaporator and the condenser, the power of the magnetic levitation compressor, and the tower water circulation flow rate. Based on the parametric model of the magnetic levitation heat pump unit structure, a three-dimensional model of the magnetic levitation heat pump unit is constructed using BIM technology. According to the heating demand of the tower water temperature, the heat transfer process under winter and summer conditions is simulated, and a three-dimensional dynamic simulation model of the magnetic levitation heat pump unit with synchronous mapping is constructed.

[0019] As a further improvement of the present invention: The three-dimensional model of the magnetic levitation heat pump unit constructed by using BIM technology includes:

[0020] Mark the set temperature rise range of the evaporator and condenser temperatures, the compressor speed-power curve, and the heat transfer coefficient of the plate heat exchanger on the three-dimensional dynamic simulation model;

[0021] The set temperature rise range of the evaporator and condenser temperatures includes:

[0022] According to the winter working condition, the first temperature of the circulating water absorbed by the evaporator side, according to the heating demand of the tower water temperature, adjust the compressor power, and the condenser adjusts the circulating water in the absorption water tank of the temperature rise plate heat exchanger to the second preset temperature;

[0023] According to the summer working condition, the second temperature of the circulating water absorbed by the evaporator side, according to the heating demand of the tower water temperature, adjust the compressor power, and the condenser adjusts the circulating water in the absorption water tank of the temperature rise plate heat exchanger to the second preset temperature;

[0024] The compressor speed-power curve includes: the mathematical relationship between the compressor speed Vt and the compressor power P:

[0025] P = a * Vt 2 + b * Vt + c

[0026] Wherein, a, b, and c are the compressor speed-power curve coefficients, and a, b, and c can be obtained by measuring the power at different speeds and using the least squares method for fitting;

[0027] According to the compressor data detected by the real-time sensor, correct the coefficients a, b, and c, predict the COP at different speeds through the fitting of the compressor speed-power curve, compare the predicted value of the compressor speed-power curve with the actual sensor data, and correct the compressor speed-power curve coefficients.

[0028] As a further improvement of the present invention: The heat transfer coefficient of the plate heat exchanger includes:

[0029] By constructing a dynamic plate heat exchanger heat transfer model:

[0030]

[0031] Among them, K(t) is the real-time heat transfer coefficient, K0 is the initial heat transfer coefficient, β is the cleaning factor, the cleaning factor is affected by the dirt on the surface of the plate heat exchanger, v(b) is the real-time flow rate of the circulating water, v c is the rated flow rate of the plate heat exchanger, n is the influence of the flow rate on the heat transfer coefficient, 0.5 < n < 1;

[0032] Obtain the dirt thickness on the surface of the plate heat exchanger through the sensor, adjust the cleaning factor coefficient, compare the predicted value of the dynamic plate heat exchanger heat transfer model with the actual sensor data, and correct the heat transfer coefficient.

[0033] As a further improvement of the present invention: The thermodynamic simulation of the tower water heating scheme for multiple working conditions includes:

[0034] Calculate the heat absorption on the evaporator side and the heat release on the condenser side through the evaporator side temperature, the first preset temperature on the condenser side, and the tower water temperature heating demand under winter and summer working conditions, and establish an inverse Carnot cycle dynamic equation and a COP prediction model.

[0035] As a further improvement of the present invention: The dynamic adjustment of the compressor power and the plate heat exchanger parameters by calculating the heat transfer efficiency under different working conditions includes:

[0036] According to the real-time collected operation data of the magnetic levitation heat pump unit and the tower water temperature heating demand, predict the compressor power under different working conditions through the inverse Carnot cycle equation and the heat transfer equation;

[0037] Q1 = m·c·ΔT1

[0038] Q2 = K(t)·A·ΔT LMTD

[0039]

[0040] Wherein, Q1 is the heat absorption of the evaporator, m is the circulating water flow rate, c is the specific heat capacity of the circulating water, and ΔT1 is the temperature difference of the tower water at the inlet and outlet of the evaporator side;

[0041] Q2 is the heat release of the condenser, K(t) is the dynamic heat transfer coefficient, and ΔT LMTD is the logarithmic mean temperature difference;

[0042] COP is the system energy efficiency ratio, W is the compressor power, and H is the heat transfer efficiency.

[0043] As a further improvement of the present invention: The dynamic adjustment of the compressor power and the plate heat exchanger parameters by calculating the heat transfer efficiency under different working conditions includes:

[0044] Based on the PID controller, dynamically adjust the compressor power, and adjust the compressor speed according to the deviation between the set value and the actual value of the tower water temperature.

[0045] On the other hand, the present invention also provides a heat pump control system for tower water heat recovery heating based on digital twin, including the following steps:

[0046] Data acquisition module: A magnetic levitation heat pump unit operating in the waste heat recovery process of the tower water circulation system under multiple working conditions enables the tower water heat recovery system to transfer heat within the set temperature range of the tower water heating scheme;

[0047] Digital Twin Model: Real-time collect the operation data of the magnetic levitation heat pump unit, and based on the parametric model of the magnetic levitation heat pump unit structure, construct a dynamic simulation model that synchronously maps the magnetic levitation heat pump unit;

[0048] Based on the digital twin model, conduct thermodynamic simulations on the heat absorption and heat release processes of the magnetic levitation heat pump, and simulate the waste heat recovery process of the tower water circulation system for the tower water heating schemes under multiple working conditions;

[0049] Data Feedback Module: Dynamically adjust the compressor power and plate heat exchanger parameters by calculating the heat transfer efficiency under different working conditions, and feedback to the magnetic levitation heat pump unit.

[0050] Compared with the prior art, the beneficial effects of the present invention are:

[0051] The present invention absorbs heat from the tower water system and the in-line circulating water side of the production line through the evaporator of the magnetic levitation heat pump, and releases heat through the condenser and the plate heat exchanger to heat the water tank. The operation status of the magnetic levitation heat pump unit is mapped in real time through the digital twin model to achieve dynamic heat transfer control under multiple working conditions. By optimizing the heat transfer efficiency, the compressor power and plate heat exchanger parameters are dynamically adjusted to ensure accurate control of the tower water temperature within the set range and save energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 It is a schematic flow chart of the method of the present invention.

[0053] Figure 2 It is a schematic structural diagram of the system of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0054] In order to clearly and completely understand the technical solution, the present invention will be further described below in conjunction with the embodiments and the drawings. Obviously, the described embodiments are only part of the embodiments of the present invention. All other embodiments obtained by those skilled in the art without creative efforts fall within the scope of protection of the present invention.

[0055] It should be understood that when used in this specification and the appended claims, the terms "comprises" and "comprising" indicate the presence of the described features, wholes, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or their combinations.

[0056] It should also be understood that the terms used in this specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in this specification of the present invention and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include the plural forms.

[0057] It should be further understood that the term "and / or" as used in the specification and appended claims of the present invention refers to any combination and all possible combinations of one or more of the associated listed items, and includes such combinations.

[0058] An embodiment of the present invention provides a heat pump control method for tower water heat recovery heating based on digital twin. The magnetic levitation heat pump absorbs heat from the tower water system and the in-line circulating water side of the production line through an evaporator, and releases heat through a condenser and a plate heat exchanger to heat a water tank. The method further includes the following steps:

[0059] The magnetic levitation heat pump unit operating in the waste heat recovery process of the multi-condition tower water circulation system enables heat transfer within the set temperature range of the tower water heating-up scheme in the tower water heat recovery system;

[0060] Real-time collect the operating data of the magnetic levitation heat pump unit, and based on the structural parametric model of the magnetic levitation heat pump unit, construct a dynamic simulation model that synchronously maps the magnetic levitation heat pump unit;

[0061] Based on the digital twin model, conduct thermodynamic simulation on the heat absorption and heat release processes of the magnetic levitation heat pump for the tower water heating-up schemes under multiple conditions, and simulate the waste heat recovery process of the tower water circulation system;

[0062] By calculating the heat transfer efficiency under different conditions, dynamically adjust the compressor power and plate heat exchanger parameters, and feedback to the magnetic levitation heat pump unit.

[0063] The present invention absorbs heat from the tower water system and the in-line circulating water side of the production line through the evaporator of the magnetic levitation heat pump, releases heat through the condenser and the plate heat exchanger to heat the water tank, and realizes dynamic heat transfer control under multiple conditions by real-time mapping the operating state of the magnetic levitation heat pump unit through the digital twin model. By optimizing the heat transfer efficiency, dynamically adjusting the compressor power and plate heat exchanger parameters, it ensures precise control of the tower water temperature within the set range and saves energy.

[0064] In an embodiment of the present invention, the magnetic levitation heat pump unit operating in the waste heat recovery process of the multi-condition tower water circulation system includes:

[0065] The magnetic levitation heat pump unit has a low-temperature heat absorption side, a high-temperature heat release side, and a magnetic levitation centrifugal compressor. The low-temperature heat absorption side absorbs heat in the evaporator. After the refrigerant absorbs the heat of the tower water system and the in-line circulating water and evaporates into a refrigerant gas, it does work through the high-temperature magnetic levitation centrifugal compressor, and then releases heat in the condenser through the high-temperature heat release side. The condenser releases the heat of the high-temperature and high-pressure refrigerant gas in a condensing manner;

[0066] The magnetic levitation heat pump unit adjusts the heat released by the condenser through a temperature-rising plate heat exchanger and discharges the heated circulating water into the tower water tank.

[0067] In one embodiment of the present invention, the magnetic levitation heat pump unit operating in the waste heat recovery process of the tower water circulation system under multiple working conditions further includes:

[0068] Winter condition: The evaporator side of the magnetic levitation centrifugal compressor absorbs the first temperature of the circulating water. After using the first temperature of the circulating water to do work through the high-temperature magnetic levitation centrifugal compressor, the condenser compresses the refrigerant gas and releases heat. After adjusting the heat released by the condenser through the heating plate heat exchanger, the circulating water is heated to the first preset temperature and discharged into the tower water tank, raising the water temperature of the tower water tank.

[0069] Summer condition: The evaporator side of the magnetic levitation centrifugal compressor absorbs the second temperature of the circulating water. After using the second temperature of the circulating water to do work through the high-temperature magnetic levitation centrifugal compressor, the condenser compresses the refrigerant gas and releases heat. After adjusting the heat released by the condenser through the heating plate heat exchanger, the circulating water is heated to the first preset temperature and discharged into the tower water tank, raising the water temperature of the tower water tank.

[0070] Adjustment condition: The heating plate heat exchanger absorbs the third temperature of the circulating water in the water tank, exchanges heat with the circulating water heated to the first preset temperature, adjusts the circulating water in the water tank absorbed by the heating plate heat exchanger to the second preset temperature, and the condenser side of the magnetic levitation centrifugal compressor absorbs the fourth temperature of the circulating water and releases heat after being compressed to the preset temperature.

[0071] In the present invention, in the winter condition, after the tower water is heated and utilized, it flows back to the production line side and mixes with the water on the production line side to form circulating water. The evaporator side of the magnetic levitation heat pump unit absorbs the heat of the low-temperature circulating water. After the heat is raised to a high temperature through the magnetic levitation centrifugal compressor, it exchanges heat with the circulating water in the tower water tank through the condenser, so that the circulating water in the tower water tank is heated. The rotational speed of the compressor can be dynamically adjusted to control the evaporator outlet temperature > 10°C to avoid the risk of low-temperature icing. The heating plate heat exchanger controls the heat release temperature of the circulating water after being heated by the condenser to ensure the temperature uniformity of the tower water tank; in the summer condition, after the tower water is heated and utilized, it flows back to the production line side and mixes with the water on the production line side to form circulating water. The evaporator side of the magnetic levitation heat pump unit absorbs the heat of the low-temperature circulating water. After the heat is raised to a high temperature through the magnetic levitation centrifugal compressor, it exchanges heat with the circulating water in the tower water tank through the condenser. The heating plate heat exchanger dynamically adjusts the circulating water flow rate and heat transfer coefficient to ensure that the water temperature is stable at the set value and reduce the heat dissipation loss in the high-temperature environment; in the adjustment condition, after the RO water pump in the tower water tank pumps water into the water tank, it mixes with the circulating water after heat exchange through the condenser and the heating plate heat exchanger. The temperature of the circulating water in the water tank decreases. At this time, the circulating water in the water tank is pumped into the heating plate heat exchanger, exchanges heat with the circulating water after heat exchange through the condenser to raise the temperature, and then the circulating water after heat exchange at the outlet of the condenser rises and jumps out of the condenser, discharges to the circulating water pumped into the heating plate heat exchanger in the water tank in the heating plate heat exchanger to adjust the temperature, and is pumped into the water tank to adjust the circulating water temperature in the water tank, realizing multi-stage heat utilization and maximizing waste heat recovery.

[0072] In an embodiment of the present invention, the real-time acquisition of the operation data of the magnetic levitation heat pump unit includes:

[0073] Real-time acquisition of the operation data of the magnetic levitation heat pump unit through sensors. The operation data includes the temperatures of the evaporator and condenser, the power of the magnetic levitation compressor, and the tower water circulation flow rate. Based on the parametric model of the magnetic levitation heat pump unit structure, a three-dimensional model of the magnetic levitation heat pump unit is constructed using BIM technology. According to the heating demand of the tower water temperature, the heat transfer process under winter and summer conditions is simulated, and a three-dimensional dynamic simulation model of the magnetic levitation heat pump unit with synchronous mapping is constructed.

[0074] In this embodiment, the operation data such as the temperatures of the evaporator and condenser of the magnetic levitation heat pump unit, the power of the magnetic levitation compressor, and the tower water circulation flow rate are obtained through sensors. Based on the parametric model of the magnetic levitation heat pump unit structure, a three-dimensional model of the magnetic levitation heat pump unit is constructed using BIM technology, providing reliable input for the digital twin model. By marking parameters such as the temperature ranges of the evaporator and condenser and the compressor speed-power curve, the visualization of the equipment status is realized.

[0075] In an embodiment of the present invention, the construction of the three-dimensional model of the magnetic levitation heat pump unit using BIM technology includes:

[0076] Marking the set temperature rise ranges of the evaporator and condenser temperatures, the compressor speed-power curve, and the heat transfer coefficient of the plate heat exchanger on the three-dimensional dynamic simulation model;

[0077] The set temperature rise ranges of the evaporator and condenser temperatures include:

[0078] According to the winter condition, the first temperature of the circulating water absorbed by the evaporator side is obtained. According to the heating demand of the tower water temperature, the compressor power is adjusted, and the condenser adjusts the circulating water in the absorption water tank of the heating plate heat exchanger to the second preset temperature;

[0079] According to the summer condition, the second temperature of the circulating water absorbed by the evaporator side is obtained. According to the heating demand of the tower water temperature, the compressor power is adjusted, and the condenser adjusts the circulating water in the absorption water tank of the heating plate heat exchanger to the second preset temperature;

[0080] The compressor speed-power curve includes: the mathematical relationship between the compressor speed Vt and the compressor power P:

[0081] P = a * Vt 2 + b * Vt + c

[0082] Where a, b, and c are the coefficients of the compressor speed-power curve, and a, b, and c can be obtained by measuring the power at different speeds and fitting using the least squares method;

[0083] Correct the coefficients a, b, and c according to the compressor data detected by the real-time sensor. Predict the COP at different speeds through the fitting of the compressor speed-power curve. Compare the predicted value of the compressor speed-power curve with the actual sensor data, and correct the coefficients of the compressor speed-power curve.

[0084] In this embodiment, the BIM technology is used to construct a three-dimensional model of the magnetic levitation heat pump unit. Key parameters such as the temperature range of the evaporator / condenser, the compressor speed-power curve, and the heat transfer coefficient of the plate heat exchanger are directly marked in the model to achieve real-time visual monitoring of the equipment status.

[0085] The evaporator side absorbs the low-temperature circulating water. According to the heating demand of the tower water, the compressor operates according to the optimized curve, dynamically adjusts the compressor power, and the condenser precisely controls the temperature of the circulating water through the temperature-rising plate heat exchanger. Fit the coefficients through experimental data, accurately predict the compressor power at different speeds, and the sensor collects the operation data of the magnetic levitation heat pump unit in real time, dynamically correct the model parameters to ensure the prediction accuracy. Combine the COP prediction model to optimize the operation range of the compressor and improve the energy efficiency of the compressor power.

[0086] In an embodiment of the present invention, the heat transfer coefficient of the plate heat exchanger includes:

[0087] By constructing a dynamic plate heat exchanger heat transfer model:

[0088]

[0089] where K(t) is the real-time heat transfer coefficient, K0 is the initial heat transfer coefficient, β is the cleaning factor, the cleaning factor is affected by the dirt on the surface of the plate heat exchanger, v(b) is the real-time flow rate of the circulating water, v c is the rated flow rate of the plate heat exchanger, n is the influence of the flow rate on the heat transfer coefficient, and 0.5 < n < 1;

[0090] Obtain the dirt thickness on the surface of the plate heat exchanger through the sensor, adjust the cleaning factor coefficient, compare the predicted value of the dynamic plate heat exchanger heat transfer model with the actual sensor data, and correct the heat transfer coefficient.

[0091] In this embodiment, by real-time monitoring the dirt thickness of the plate heat exchanger and dynamically updating the cleaning factor, the heat transfer coefficient can be adjusted according to the circulating water flow rate.

[0092] In an embodiment of the present invention, the thermodynamic simulation of the tower water heating scheme under multiple working conditions includes:

[0093] Calculate the heat absorption on the evaporator side and the heat release on the condenser side through the temperature on the evaporator side, the first preset temperature on the condenser side, and the heating demand of the tower water under winter and summer working conditions, and establish an inverse Carnot cycle dynamic equation and a COP prediction model.

[0094] Further, the dynamic adjustment of the compressor power and the plate heat exchanger parameters by calculating the heat transfer efficiency under different working conditions includes:

[0095] According to the real-time collected operation data of the magnetic levitation heat pump unit and the heating demand of the tower water temperature, predict the compressor power under different working conditions through the inverse Carnot cycle equation and the heat transfer equation;

[0096] Q1 = m·c·ΔT1

[0097] Q2 = K(t)·A·ΔT LMTD

[0098]

[0099] Wherein, Q1 is the heat absorption of the evaporator, m is the circulating water flow rate, c is the specific heat capacity of the circulating water, and ΔT1 is the temperature difference of the tower water at the inlet and outlet of the evaporator side;

[0100] Q2 is the heat release of the condenser, K(t) is the dynamic heat transfer coefficient, and ΔT LMTD is the logarithmic mean temperature difference;

[0101] COP is the system energy efficiency ratio, W is the compressor power, and H is the heat transfer efficiency.

[0102] In this embodiment, the heat absorption of the low-temperature heat source is calculated by real-time monitoring of the circulating water flow rate and temperature difference. The dynamic heat transfer coefficient is combined with the fouling factor and flow rate, and the heat release model is corrected in real time. Through the real-time sensor data, the heat transfer coefficient and compressor efficiency are corrected in real time to improve the control accuracy

[0103] In an embodiment of the present invention, the dynamic adjustment of the compressor power and the plate heat exchanger parameters by calculating the heat transfer efficiency under different working conditions includes:

[0104] Based on the PID controller, the compressor power is dynamically adjusted, and the compressor speed is adjusted according to the deviation between the set value and the actual value of the tower water temperature.

[0105] On the other hand, the present invention also provides a heat pump control system for tower water heat recovery heating based on digital twin, including the following steps:

[0106] Data acquisition module: A magnetic levitation heat pump unit operating in the waste heat recovery process of the tower water circulation system under multiple working conditions enables the tower water heat recovery system to transfer heat within the set temperature range of the tower water heating scheme;

[0107] Digital twin model: Real-time collect the operation data of the magnetic levitation heat pump unit, and construct a dynamic simulation model that synchronously maps the magnetic levitation heat pump unit based on the structural parametric model of the magnetic levitation heat pump unit;

[0108] Based on the digital twin model, conduct thermodynamic simulations on the heat absorption and heat release processes of the magnetic levitation heat pump for the tower water heating schemes under multiple working conditions, and simulate the waste heat recovery process of the tower water circulation system;

[0109] Data feedback module: Dynamically adjust the compressor power and plate heat exchanger parameters by calculating the heat transfer efficiency under different working conditions, and feedback them to the magnetic levitation heat pump unit.

[0110] In one embodiment, during the winter operation mode, the low-temperature side of the production line is 15°C, and the high-temperature side is 18°C. After the tower water is heated and utilized, it flows back to the production line side and mixes with the water on the production line side to form circulating water. The magnetic levitation heat pump absorbs the heat of the circulating water at 18°C on the high-temperature side of the production line. After the circulating water absorbs heat and is cooled to 11°C, it is discharged from the evaporator outlet. After the absorbed heat is raised to a high temperature by the magnetic levitation centrifugal compressor, it exchanges heat with the circulating water in the tower water tank through the condenser. Specifically, the condenser exchanges heat with the tower water tank to form circulating water at 80°C and discharges it from the condenser outlet. At the same time, 80°C circulating water is pumped to the heating plate exchanger. The heating plate exchanger adjusts the 80°C circulating water to 78°C, and then pumps it into the tower water tank to raise the temperature of the circulating water in the tower water tank. After the 18°C RO water in the tower water tank is pumped into the tank, it mixes with the 78°C circulating water after heat exchange through the condenser and the heating plate exchanger. The temperature of the circulating water in the tank decreases, forming 45°C circulating water. At this time, the 45°C circulating water in the tank is pumped to the heating plate exchanger to exchange heat with the 80°C circulating water after heat exchange through the condenser and increase the temperature. The 45°C circulating water becomes 75°C circulating water. The 75°C circulating water is then heated to 80°C by the circulating water exchanging heat at the condenser outlet and then discharged from the condenser and sent to the heating plate exchanger to exchange heat with the circulating water pumped into the tank in the heating plate exchanger to adjust the temperature, and then pumped into the tank to adjust the temperature of the circulating water in the tank, realizing multi-stage heat utilization and maximizing waste heat recovery. During the heat exchange process, the operation status of the magnetic levitation heat pump unit is mapped in real time through the digital twin model to realize dynamic heat transfer control under multiple working conditions. Through optimizing the heat transfer efficiency, the compressor power and the plate exchanger parameters are dynamically adjusted to ensure precise control of the tower water temperature within the set range, saving energy. The evaporator side absorbs low-temperature circulating water. According to the tower water heating demand, the compressor operates according to the optimized curve and dynamically adjusts the compressor power. The condenser precisely controls the circulating water temperature through the heating plate exchanger. The compressor power at different speeds is accurately predicted through the experimental data fitting coefficient. The sensors collect the operation data of the magnetic levitation heat pump unit in real time and dynamically correct the model parameters to ensure the prediction accuracy. Combining with the COP prediction model, the operation range of the compressor is optimized to improve the energy efficiency of the compressor power. After the temperature of the circulating water in the tower water tank is heated to 78°C, the 78°C circulating water is sent to the extraction process line, where it is mixed with steam in the heating section of the extraction process line to assist in heating up, and the 78°C circulating water is raised to 95°C. The steam is used as auxiliary heating to 90°C and then supplied to the extraction equipment and the sugar dissolving equipment. In the sugar dissolving equipment, the ice water system is used in combination with the cooling plate exchanger to assist in heat exchange and cooling, and heat exchange is carried out according to different process requirements. After heat exchange, the circulating water is discharged to the production line side through the tower water system. After the product beverage is processed in the extraction equipment and the sugar dissolving equipment, the 18°C product beverage is output to the blending tank for blending.

[0111] In summary, after reading the present invention document, those of ordinary skill in the art can make various corresponding transformation schemes without creative mental labor according to the technical solutions and technical concepts of the present invention, and all of them fall within the scope protected by the present invention.

Claims

1. A heat pump control method for tower water heat recovery heating based on digital twin, characterized in that, The magnetic levitation heat pump absorbs heat from the tower water system and the circulating water side of the production line through the evaporator, and releases heat to heat the water tank through the condenser and the plate heat exchanger. The method further includes the following steps: During the waste heat recovery process of the tower water circulation system under multiple operating conditions, the magnetic levitation heat pump unit operates to transfer heat within the set temperature range of the tower water heating scheme of the tower water heat recovery system; The operating data of the magnetic levitation heat pump unit is collected in real time, and based on the structural parametric model of the magnetic levitation heat pump unit, a dynamic simulation model that is synchronously mapped to the magnetic levitation heat pump unit is constructed; Based on the digital twin model, thermodynamic simulations are performed on the heat absorption and heat release processes of the magnetic levitation heat pump for the tower water heating schemes under multiple operating conditions to simulate the waste heat recovery process of the tower water circulation system; By calculating the heat transfer efficiency under different operating conditions, the compressor power and the plate heat exchanger parameters are dynamically adjusted and fed back to the magnetic levitation heat pump unit.

2. The heat pump control method for tower water heat recovery heating based on digital twin according to claim 1, wherein, The magnetic levitation heat pump unit operating during the waste heat recovery process of the tower water circulation system under multiple operating conditions includes: The magnetic levitation heat pump unit has a low-temperature heat absorption side, a high-temperature heat release side, and a magnetic levitation centrifugal compressor. The low-temperature heat absorption side absorbs heat in the evaporator. After the refrigerant absorbs the heat of the tower water system and the circulating water in the production line and evaporates into refrigerant gas, it does work through the high-temperature magnetic levitation centrifugal compressor, and then releases heat in the condenser on the high-temperature heat release side. The condenser releases the heat of the high-temperature and high-pressure refrigerant gas in a condensing manner; The magnetic levitation heat pump unit adjusts the heat released by the condenser through the heating plate heat exchanger and discharges the heated circulating water into the tower water tank.

3. A heat pump control method for tower water heat recovery heating based on digital twin according to claim 1, characterized in that, The magnetic levitation heat pump unit operating during the waste heat recovery process of the tower water circulation system under multiple operating conditions further includes: Winter condition: The evaporator side of the magnetic levitation centrifugal compressor absorbs the first temperature of the circulating water. After using the first temperature of the circulating water to do work through the high-temperature magnetic levitation centrifugal compressor, the condenser compresses the refrigerant gas and releases heat. By adjusting the heat released by the condenser through the heating plate heat exchanger, the circulating water is heated to the first preset temperature and discharged into the tower water tank to raise the water temperature of the tower water tank; Summer condition: The evaporator side of the magnetic levitation centrifugal compressor absorbs the second temperature of the circulating water. After using the second temperature of the circulating water to do work through the high-temperature magnetic levitation centrifugal compressor, the condenser compresses the refrigerant gas and releases heat. By adjusting the heat released by the condenser through the heating plate heat exchanger, the circulating water is heated to the first preset temperature and discharged into the tower water tank to raise the water temperature of the tower water tank; Adjustment condition: The heating plate heat exchanger absorbs the third temperature of the circulating water in the water tank, exchanges heat with the circulating water heated to the first preset temperature, adjusts the circulating water absorbed by the heating plate heat exchanger in the water tank to the second preset temperature, and the condenser side of the magnetic levitation centrifugal compressor absorbs the fourth temperature of the circulating water and releases heat after being compressed to the preset temperature.

4. A heat pump control method for tower water heat recovery heating based on digital twin according to claim 1, characterized in that, The real-time collection of the operating data of the magnetic levitation heat pump unit includes: Real-time collect the operation data of the magnetic levitation heat pump unit through sensors. The operation data includes the temperatures of the evaporator and condenser, the power of the magnetic levitation compressor, and the tower water circulation flow rate. Based on the parametric model of the magnetic levitation heat pump unit structure, use BIM technology to construct a three-dimensional model of the magnetic levitation heat pump unit. According to the heating demand of the tower water temperature, simulate the heat transfer process under winter and summer conditions, and construct a three-dimensional dynamic simulation model of the magnetic levitation heat pump unit with synchronous mapping.

5. A heat pump control method for tower water heat recovery heating based on digital twin according to claim 1, characterized in that, The construction of the three-dimensional model of the magnetic levitation heat pump unit using BIM technology includes: Mark the set temperature rise range of the evaporator and condenser temperatures, the compressor speed-power curve, and the heat transfer coefficient of the plate heat exchanger on the three-dimensional dynamic simulation model; The set temperature rise range of the evaporator and condenser temperatures includes: According to the winter condition, the evaporator side absorbs the first temperature of the circulating water. According to the heating demand of the tower water temperature, adjust the compressor power. The condenser adjusts the circulating water in the absorption water tank of the temperature-rising plate heat exchanger to the second preset temperature; According to the summer condition, the evaporator side absorbs the second temperature of the circulating water. According to the heating demand of the tower water temperature, adjust the compressor power. The condenser adjusts the circulating water in the absorption water tank of the temperature-rising plate heat exchanger to the second preset temperature; The compressor speed-power curve includes: the mathematical relationship between the compressor speed Vt and the compressor power P: P = a * Vt 2 + b * Vt + c Among them, a, b, and c are the compressor speed-power curve coefficients, and a, b, and c can be obtained by measuring the power at different speeds and using the least squares method for fitting; Correct the coefficients a, b, and c according to the compressor data detected by the real-time sensor. Predict the COP at different speeds through the compressor speed-power curve fitting. Compare the predicted value of the compressor speed-power curve with the actual sensor data, and correct the compressor speed-power curve coefficients.

6. A heat pump control method for tower water heat recovery heating based on digital twin according to claim 1, characterized in that, The heat transfer coefficient of the plate heat exchanger includes: By constructing a dynamic plate heat exchanger heat transfer model: Among them, K(t) is the real-time heat transfer coefficient, K0 is the initial heat transfer coefficient, β is the cleaning factor, which is affected by the fouling on the surface of the plate heat exchanger, v(b) is the real-time flow velocity of the circulating water, and v c is the rated flow velocity of the plate heat exchanger, n is the influence of the flow velocity on the heat transfer coefficient, and 0.5 < n < 1; Use the sensor to obtain the fouling thickness on the surface of the plate heat exchanger, adjust the cleaning factor coefficient, compare the predicted value of the dynamic plate heat exchanger heat transfer model with the actual sensor data, and correct the heat transfer coefficient.

7. A heat pump control method for tower water heat recovery heating based on digital twin according to claim 1, characterized in that, The thermodynamic simulation of the tower water temperature rise scheme under multiple conditions includes: Based on the evaporator side temperature, the first preset temperature on the condenser side, and the heating demand of the tower water temperature under winter and summer conditions, calculate the heat absorption on the evaporator side and the heat release on the condenser side, and establish an inverse Carnot cycle dynamic equation and a COP prediction model.

8. A heat pump control method for tower water heat recovery heating based on digital twin according to claim 1, characterized in that, The dynamic adjustment of the compressor power and the plate heat exchanger parameters by calculating the heat transfer efficiency under different conditions includes: According to the real-time collected operation data of the magnetic levitation heat pump unit and the heating demand of the tower water temperature, predict the compressor power under different conditions through the inverse Carnot cycle equation and the heat transfer equation; Q1 = m·c·ΔT1 Q2 = K(t)·A·ΔT LMTD Among them, Q1 is the heat absorption of the evaporator, m is the circulating water flow rate, c is the specific heat capacity of the circulating water, and ΔT1 is the temperature difference of the tower water at the inlet and outlet of the evaporator side; Q2 is the heat released by the condenser, K(t) is the dynamic heat transfer coefficient, and ΔT LMTD is the logarithmic mean temperature difference; COP is the system energy efficiency ratio, W is the compressor power, and H is the heat transfer efficiency.

9. A heat pump control method for tower water heat recovery heating based on digital twin according to claim 1, characterized in that, The dynamic adjustment of the compressor power and the plate heat exchanger parameters by calculating the heat transfer efficiency under different conditions includes: Based on the PID controller, dynamically adjust the compressor power, and adjust the compressor speed according to the deviation between the set value and the actual value of the tower water temperature.

10. A heat pump control system for tower water heat recovery heating based on digital twin, characterized in that, A heat pump control method for tower water heat recovery heating based on digital twin as described in any one of claims 1-9, further comprising the following steps: Data acquisition module: A magnetic levitation heat pump unit operating during the waste heat recovery process of a tower water circulation system under multiple operating conditions, enabling heat transfer within the set temperature range of the tower water heating-up scheme in the tower water heat recovery system; Digital twin model: Real-time collection of the operating data of the magnetic levitation heat pump unit, and construction of a dynamic simulation model that synchronously maps the magnetic levitation heat pump unit based on the structural parametric model of the magnetic levitation heat pump unit; Based on the digital twin model, thermodynamic simulation of the heat absorption and heat release processes of the magnetic levitation heat pump is carried out for the tower water heating-up schemes under multiple operating conditions to simulate the waste heat recovery process of the tower water circulation system; Data feedback module: By calculating the heat transfer efficiency under different operating conditions, dynamically adjust the compressor power and plate heat exchanger parameters and feedback them to the magnetic levitation heat pump unit.

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