Low temperature heat source refrigeration system and method

Abstract

This invention relates to the field of low-temperature heat source refrigeration technology, specifically disclosing a low-temperature heat source refrigeration system and method. The system includes an energy transfer topology construction module, an energy supply-demand deviation vector generation module, and an inter-stage energy distribution controller. This invention constructs the key nodes of a three-stage refrigeration unit as an energy transfer topology diagram, generates a five-dimensional energy supply-demand deviation vector reflecting the temperature deviation of each node, calculates the threshold adjustment value through a deviation-threshold mapping matrix, and adjusts the flow rate of each heat transfer path. By abstracting the heat transfer path into a directed graph structure, this invention utilizes multi-dimensional deviation vectors and mapping matrices to achieve multi-variable collaborative control, solving the problem of difficult-to-accurate matching of heat supply and demand imbalance in multi-stage refrigeration systems, improving system energy efficiency and operational stability, and reducing the operating energy consumption of carbon dioxide capture, utilization, and storage systems.

Description

Technical Field

[0001] This invention relates to the field of low-temperature heat source refrigeration technology, and particularly to a low-temperature heat source refrigeration system and method. Background Technology

[0002] Low-temperature heat source refrigeration technology utilizes low-grade hot water at 60-80℃ to drive absorption or adsorption refrigeration systems, showing broad application prospects in industrial waste heat recovery, carbon capture, utilization, and storage. Existing technologies typically employ a three-stage cascade refrigeration architecture, connecting absorption and adsorption refrigeration in series. The heat dissipation from one stage refrigeration unit drives the next, achieving tiered cooling output to meet the refrigeration requirements of interstage cooling during compression, liquefaction pretreatment, and deep liquefaction in carbon dioxide capture, utilization, and storage systems.

[0003] However, existing technologies have the following drawbacks: when the temperature of the driving heat source fluctuates or the cooling demand of each stage of the refrigeration unit changes, the heat transfer between stages lacks a dynamic and coordinated adjustment mechanism, leading to an imbalance between heat supply and demand, a decrease in system energy efficiency, and consequently, an increase in the overall energy consumption of the carbon capture, utilization, and storage system, affecting the economics and stability of carbon capture. Existing solutions mostly adopt the method of independently adjusting each refrigeration unit, failing to construct a unified control model from the perspective of the overall energy transfer network. This makes it impossible to achieve coordinated optimization of multi-stage heat transfer paths and fully realize the energy-saving potential driven by low-grade heat energy. Furthermore, current industrial internet platforms already possess the capabilities for data acquisition, global coordinated scheduling, and intelligent optimization of industrial energy systems, supporting integrated management and control of multiple devices and links. Existing solutions, however, do not integrate with industrial internet platforms to achieve end-to-end data interoperability and intelligent control of the refrigeration system, remaining in an independent and decentralized control mode.

[0004] Therefore, this invention proposes a low-temperature heat source refrigeration system and method. Summary of the Invention

[0005] This invention provides a low-temperature heat source refrigeration system and method, which achieves coordinated control of multi-level heat energy transfer paths through energy transfer topology diagram and five-dimensional deviation vector, effectively improving the utilization efficiency of low-grade heat energy and significantly reducing the operating energy consumption of carbon dioxide capture, utilization and storage systems.

[0006] This invention provides a low-temperature heat source refrigeration system, comprising: The energy transfer topology construction module is used to construct an energy transfer topology graph containing five nodes, consisting of the generator outlet of the first-stage absorption refrigeration unit, the desorber inlet of the second-stage adsorption refrigeration unit, the desorber outlet of the second-stage adsorption refrigeration unit, the desorber inlet of the third-stage adsorption refrigeration unit, and the desorber outlet of the third-stage adsorption refrigeration unit. The heat energy transfer path between the generator outlet of the first-stage absorption refrigeration unit and the desorber inlet of the second-stage adsorption refrigeration unit is constructed as the first directed edge, and the heat energy transfer path between the desorber outlet of the second-stage adsorption refrigeration unit and the desorber inlet of the third-stage adsorption refrigeration unit is constructed as the second directed edge. The output cooling capacity of each refrigeration unit is constructed as the cooling capacity output attribute of the outlet node of each refrigeration unit. The energy supply and demand deviation vector generation module is used to collect the real-time temperature values ​​of each node in the energy transfer topology diagram, and generate a five-dimensional energy supply and demand deviation vector with five nodes as the dimensions based on the deviation between the real-time temperature values ​​of each node and the preset reference temperature range of each node. The interstage energy distribution controller is used to input the five-dimensional energy supply and demand deviation vector into a preset deviation-valve mapping matrix, calculate the first valve adjustment value corresponding to the first directed edge and the second valve adjustment value corresponding to the second directed edge through the deviation-valve mapping matrix, and adjust the heat transfer flow rate of the first directed edge and the second directed edge according to the first valve adjustment value and the second valve adjustment value respectively.

[0007] Furthermore, the energy transfer topology building blocks include: The node calibration unit is used to calibrate the generator outlet of the first-stage absorption refrigeration unit as the first node, the desorber inlet of the second-stage adsorption refrigeration unit as the second node, the desorber outlet of the second-stage adsorption refrigeration unit as the third node, the desorber inlet of the third-stage adsorption refrigeration unit as the fourth node, and the desorber outlet of the third-stage adsorption refrigeration unit as the fifth node. A directed edge construction unit is used to construct the heat transfer path between the first node and the second node as a first directed edge, and the heat transfer path between the third node and the fourth node as a second directed edge; The node attribute assignment unit is used to assign the output cooling temperature value of the first-stage absorption refrigeration unit to the cooling output attribute of the first node, the output cooling temperature value of the second-stage adsorption refrigeration unit to the cooling output attribute of the third node, and the output cooling temperature value of the third-stage adsorption refrigeration unit to the cooling output attribute of the fifth node.

[0008] Furthermore, the energy supply-demand deviation vector generation module includes: The node temperature acquisition unit is used to acquire the real-time temperature values ​​of the first node, the second node, the third node, the fourth node, and the fifth node. The reference temperature range storage unit is used to store the preset reference temperature ranges corresponding to the first node, the second node, the third node, the fourth node, and the fifth node, wherein the preset reference temperature range of the first node is 60-80℃, the preset reference temperature range of the second node is 30-50℃, the preset reference temperature range of the third node is 30-50℃, the preset reference temperature range of the fourth node is 20-40℃, and the preset reference temperature range of the fifth node is 20-40℃. The deviation calculation unit is used to calculate the difference between the real-time temperature value of each node and the center value of the corresponding reference temperature range. The difference is divided by half the width of the reference temperature range to obtain the normalized deviation value of each node. The vector generation unit is used to arrange the normalized deviation values ​​of the first node, second node, third node, fourth node, and fifth node in the node order to generate a five-dimensional energy supply and demand deviation vector.

[0009] Furthermore, the interstage energy distribution controller includes: The deviation-threshold mapping matrix storage unit is used to store the deviation-threshold mapping matrix of the five-dimensional input and two-dimensional output. The deviation-threshold mapping matrix is ​​a 2-row, 5-column matrix. Each element in the matrix represents the contribution weight of the deviation value of the corresponding dimension to the corresponding threshold adjustment value. The matrix multiplication unit is used to multiply the five-dimensional energy supply and demand deviation vector with the deviation-valve mapping matrix to obtain a two-dimensional valve adjustment vector, which includes a first valve adjustment value and a second valve adjustment value. The valve-to-opening conversion unit is used to convert the first valve adjustment value into the opening adjustment amount of the first directed edge, and to convert the second valve adjustment value into the opening adjustment amount of the second directed edge.

[0010] Furthermore, the deviation-threshold mapping matrix storage unit includes: The offline learning subunit is used to record the five-dimensional energy supply and demand deviation vector and the corresponding historical threshold adjustment value at multiple historical moments during the initial operation phase of the system. The five-dimensional energy supply and demand deviation vector at multiple historical moments is used as the input sample matrix, and the corresponding historical threshold adjustment value is used as the output sample matrix. The deviation-threshold mapping matrix is ​​solved by the least squares method to minimize the sum of the squared errors of the product of the deviation-threshold mapping matrix and the input sample matrix and the output sample matrix.

[0011] Furthermore, the deviation-threshold mapping matrix storage unit includes: The online update subunit is used to continuously record the five-dimensional energy supply and demand deviation vector and the current output threshold adjustment value during system operation. It adds the current data to the historical data set, and re-solves the deviation-threshold mapping matrix using the least squares method with the updated historical data set every preset update cycle. It calculates the difference between the re-solved deviation-threshold mapping matrix and the currently used deviation-threshold mapping matrix. When the difference is less than the preset difference threshold, the update stops and the system continues to run using the currently used deviation-threshold mapping matrix.

[0012] Furthermore, the valve degree-opening degree conversion unit includes: The opening adjustment amount calculation subunit is used to multiply the first valve adjustment value by the opening adjustment coefficient of the first directed edge to obtain the opening adjustment amount of the first directed edge, and multiply the second valve adjustment value by the opening adjustment coefficient of the second directed edge to obtain the opening adjustment amount of the second directed edge. The target opening value calculation subunit is used to add the reference opening value of the first directed edge to the opening adjustment amount of the first directed edge to obtain the target opening value of the first directed edge, and add the reference opening value of the second directed edge to the opening adjustment amount of the second directed edge to obtain the target opening value of the second directed edge. The control signal sending subunit is used to send a control signal corresponding to the first target opening value to the actuator of the first directed edge, and to send a control signal corresponding to the second target opening value to the actuator of the second directed edge.

[0013] Furthermore, the reference opening value of the first directed edge and the reference opening value of the second directed edge are determined in the following manner: Obtain the standard cooling capacity requirements for the interstage cooling stage of carbon dioxide compression and the standard cooling capacity requirements for the pre-cooling stage of carbon dioxide liquefaction in the CCUS system. Based on the standard cooling capacity requirement of the carbon dioxide compression interstage cooling stage and the rated output cooling capacity of the first-stage absorption refrigeration unit, the heat energy required to be provided by the generator outlet of the first-stage absorption refrigeration unit is determined, and then the reference opening value of the first directed edge is determined. Based on the standard cooling capacity requirement of the carbon dioxide liquefaction precooling stage and the rated output cooling capacity of the secondary adsorption refrigeration unit, the heat energy that the desorber of the secondary adsorption refrigeration unit needs to absorb is determined, and then the reference opening value of the second directed edge is determined.

[0014] Furthermore, it also includes: The temperature difference calculation module is used to collect the real-time temperature value of the generator outlet of the first-stage absorption refrigeration unit and the real-time temperature value of the desorber inlet of the second-stage adsorption refrigeration unit, calculate the temperature difference between the two ends of the first directed edge, collect the real-time temperature value of the desorber outlet of the second-stage adsorption refrigeration unit and the real-time temperature value of the desorber inlet of the third-stage adsorption refrigeration unit, and calculate the temperature difference between the two ends of the second directed edge. The priority switching module is used to decrease the first threshold adjustment value and increase the second threshold adjustment value when the temperature difference between the two ends of the first directed edge is less than the first temperature difference threshold, and decrease the second threshold adjustment value and increase the first threshold adjustment value when the temperature difference between the two ends of the second directed edge is less than the second temperature difference threshold.

[0015] This invention provides a low-temperature heat source cooling method, comprising: The generator outlet of the first-stage absorption refrigeration unit, the desorber inlet of the second-stage adsorption refrigeration unit, the desorber outlet of the second-stage adsorption refrigeration unit, the desorber inlet of the third-stage adsorption refrigeration unit, and the desorber outlet of the third-stage adsorption refrigeration unit are constructed as an energy transfer topology graph containing five nodes. The heat energy transfer path between the generator outlet of the first-stage absorption refrigeration unit and the desorber inlet of the second-stage adsorption refrigeration unit is constructed as a first directed edge, and the heat energy transfer path between the desorber outlet of the second-stage adsorption refrigeration unit and the desorber inlet of the third-stage adsorption refrigeration unit is constructed as a second directed edge. The output cooling capacity of each refrigeration unit is constructed as the cooling capacity output attribute of the outlet node of each refrigeration unit. Collect the real-time temperature values ​​of each node in the energy transfer topology diagram, and generate a five-dimensional energy supply and demand deviation vector with five nodes as the dimensions based on the deviation between the real-time temperature values ​​of each node and the preset reference temperature range of each node. The five-dimensional energy supply and demand deviation vector is input into the preset deviation-valve mapping matrix. The first valve adjustment value corresponding to the first directed edge and the second valve adjustment value corresponding to the second directed edge are calculated through the deviation-valve mapping matrix. The heat transfer flow rate of the first directed edge and the second directed edge is adjusted according to the first valve adjustment value and the second valve adjustment value, respectively.

[0016] The beneficial effects of this invention compared to existing technologies are as follows: In existing technologies, the heat transfer paths of a three-stage cascade refrigeration system are independent. When the temperature of the driving heat source fluctuates or the cooling demand of each stage changes, it is impossible to coordinate and adjust from the perspective of the overall energy transfer network, leading to an imbalance between heat supply and demand, a decrease in system energy efficiency, and consequently, an increase in the operating energy consumption of the carbon dioxide capture, utilization, and storage system. This invention constructs the key nodes of the three-stage refrigeration unit as an energy transfer topology graph, abstracts the heat transfer paths as directed edge structures, and generates a five-dimensional energy supply and demand deviation vector reflecting the temperature deviation of each node. It utilizes a deviation-threshold mapping matrix to achieve multi-variable coordinated control and dynamically adjust the flow rate of each heat transfer path. This scheme achieves coordinated optimization of multi-stage heat transfer paths from the perspective of the overall energy transfer network, enabling real-time response to heat source fluctuations and load changes. It effectively improves the energy utilization efficiency of low-grade heat-driven refrigeration systems, significantly reduces the operating energy consumption of carbon dioxide capture, utilization, and storage systems, provides key energy-saving support for the large-scale application of carbon capture technology, and has significant value in promoting the low-carbon development of the carbon utilization industry chain. This invention can be connected to an industrial internet platform to complete real-time cloud uploading and remote monitoring of key node temperature, valve degree adjustment, and energy efficiency data. Relying on the global scheduling capabilities of the industrial internet platform, it can further realize the coordinated energy-saving operation of the refrigeration system and the CCUS system.

[0017] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in this application.

[0018] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0019] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a diagram showing the connection relationships of the low-temperature heat source refrigeration system modules in an embodiment of the present invention; Figure 2 This is a flowchart illustrating the generation process of the energy transfer topology and the five-dimensional deviation vector in an embodiment of the present invention. Detailed Implementation

[0020] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0021] refer to Figure 1 , Figure 2The present invention provides an embodiment of a low-temperature heat source refrigeration system, comprising: The energy transfer topology construction module is used to construct an energy transfer topology graph containing five nodes, consisting of the generator outlet of the first-stage absorption refrigeration unit, the desorber inlet of the second-stage adsorption refrigeration unit, the desorber outlet of the second-stage adsorption refrigeration unit, the desorber inlet of the third-stage adsorption refrigeration unit, and the desorber outlet of the third-stage adsorption refrigeration unit. The heat energy transfer path between the generator outlet of the first-stage absorption refrigeration unit and the desorber inlet of the second-stage adsorption refrigeration unit is constructed as the first directed edge, and the heat energy transfer path between the desorber outlet of the second-stage adsorption refrigeration unit and the desorber inlet of the third-stage adsorption refrigeration unit is constructed as the second directed edge. The output cooling capacity of each refrigeration unit is constructed as the cooling capacity output attribute of the outlet node of each refrigeration unit. The energy supply and demand deviation vector generation module is used to collect the real-time temperature values ​​of each node in the energy transfer topology diagram, and generate a five-dimensional energy supply and demand deviation vector with five nodes as the dimensions based on the deviation between the real-time temperature values ​​of each node and the preset reference temperature range of each node. The interstage energy distribution controller is used to input the five-dimensional energy supply and demand deviation vector into a preset deviation-valve mapping matrix, calculate the first valve adjustment value corresponding to the first directed edge and the second valve adjustment value corresponding to the second directed edge through the deviation-valve mapping matrix, and adjust the heat transfer flow rate of the first directed edge and the second directed edge according to the first valve adjustment value and the second valve adjustment value respectively.

[0022] In this embodiment, the first-stage absorption refrigeration unit refers to a device unit that uses lithium bromide solution as absorbent and water as refrigerant, with 60-80°C hot water as the driving heat source. The water refrigerant is desorbed from the lithium bromide solution by heating, and after condensation, throttling, and evaporation, it absorbs heat to generate cooling capacity. This unit outputs 3-10°C of cooling capacity for the interstage cooling of carbon dioxide compression in the carbon dioxide capture, utilization, and storage system.

[0023] In this embodiment, the secondary adsorption refrigeration unit refers to a device unit that uses calcium chloride as an adsorbent and ammonia as a refrigerant, and uses the 30-50°C waste heat discharged from the generator outlet of the primary absorption refrigeration unit as a driving heat source. The ammonia refrigerant is desorbed from the calcium chloride by heating, and after condensation and evaporation, it absorbs heat to generate cooling capacity. The unit outputs cooling capacity of -15°C to -30°C for the carbon dioxide liquefaction precooling stage in the carbon dioxide capture, utilization and storage system.

[0024] In this embodiment, the three-stage adsorption refrigeration unit refers to a device unit that uses zeolite as an adsorbent and water as a refrigerant, and uses the 20-40°C waste heat discharged from the desorber outlet of the two-stage adsorption refrigeration unit as a driving heat source. The water refrigerant is desorbed from the zeolite by heating, and after condensation and evaporation, it absorbs heat to generate cooling capacity. The unit outputs cooling capacity of -30°C to -60°C for the deep liquefaction stage of carbon dioxide in the carbon dioxide capture, utilization and storage system.

[0025] In this embodiment, the generator outlet of the first-stage absorption refrigeration unit, the desorber inlet of the second-stage adsorption refrigeration unit, the desorber outlet of the second-stage adsorption refrigeration unit, the desorber inlet of the third-stage adsorption refrigeration unit, and the desorber outlet of the third-stage adsorption refrigeration unit refer to five key temperature monitoring points selected from the three-stage refrigeration unit. The generator outlet of the first-stage absorption refrigeration unit is the heat source output end, the desorber inlet and outlet of the second-stage adsorption refrigeration unit are the heat source receiving end and the waste heat output end, respectively, and the desorber inlet and outlet of the third-stage adsorption refrigeration unit are the heat source receiving end and the waste heat output end, respectively. These five monitoring points constitute five nodes in the energy transfer topology.

[0026] In this embodiment, the heat transfer path refers to the physical channel through which heat energy is transferred from the generator outlet of the first-stage absorption refrigeration unit to the desorber inlet of the second-stage adsorption refrigeration unit, and the physical channel through which heat energy is transferred from the desorber outlet of the second-stage adsorption refrigeration unit to the desorber inlet of the third-stage adsorption refrigeration unit. These two paths are constructed as the first directed edge and the second directed edge, respectively, to characterize the directionality and transfer relationship of heat energy flow.

[0027] In this embodiment, the refrigeration unit outlet node refers to the node in the energy transfer topology corresponding to the physical location where the actual cooling output of each refrigeration unit is located. Specifically, the outlet node of the first-stage absorption refrigeration unit corresponds to the first node, which is associated with the 3-10°C cooling output temperature value at the outlet of the evaporator of the first-stage absorption refrigeration unit; the outlet node of the second-stage adsorption refrigeration unit corresponds to the third node, which is associated with the -15°C to -30°C cooling output temperature value at the outlet of the first evaporator of the second-stage adsorption refrigeration unit; and the outlet node of the tertiary adsorption refrigeration unit corresponds to the fifth node, which is associated with the -30°C to -60°C cooling output temperature value at the outlet of the second evaporator of the tertiary adsorption refrigeration unit. While there is a correspondence between the refrigeration unit outlet nodes and the nodes in the energy transfer topology, they are not entirely identical. The energy transfer topology contains five nodes, of which the first, third, and fifth nodes are designated as the outlet nodes of each refrigeration unit, while the second and fourth nodes, as intermediate nodes in the heat transfer path, do not perform cooling output functions. This correspondence is established through a node calibration unit. Specifically, the node calibration unit calibrates the generator outlet of the first-stage absorption refrigeration unit as the first node, the desorber outlet of the second-stage adsorption refrigeration unit as the third node, and the desorber outlet of the third-stage adsorption refrigeration unit as the fifth node, so that the first node, the third node, and the fifth node respectively carry the cooling output attribute of the corresponding refrigeration unit outlet node.

[0028] In this embodiment, the output cooling capacity of each refrigeration unit refers to the 3-10℃ cooling capacity temperature value output from the evaporator outlet of the first-stage absorption refrigeration unit, the -15℃ to -30℃ cooling capacity temperature value output from the first evaporator outlet of the second-stage adsorption refrigeration unit, and the -30℃ to -60℃ cooling capacity temperature value output from the second evaporator outlet of the third-stage adsorption refrigeration unit. These cooling capacity temperature values ​​are assigned as the cooling capacity output attributes of the corresponding nodes and are used to perform correlation calculations with the energy supply and demand deviation vector.

[0029] In this embodiment, collecting the real-time temperature values ​​of each node in the energy transfer topology diagram refers to acquiring the current temperature values ​​of each monitoring point in real time through temperature sensors respectively set at the first node, second node, third node, fourth node, and fifth node. The real-time temperature value of the first node reflects the actual temperature of the generator outlet of the first-stage absorption refrigeration unit, the real-time temperature values ​​of the second and third nodes reflect the actual temperatures of the desorber inlet and outlet of the second-stage adsorption refrigeration unit, and the real-time temperature values ​​of the fourth and fifth nodes reflect the actual temperatures of the desorber inlet and outlet of the third-stage adsorption refrigeration unit.

[0030] In this embodiment, the preset deviation-threshold mapping matrix is ​​a 2x5 matrix, which is predetermined through offline learning. Each element in the matrix represents the contribution weight of the deviation value of the corresponding dimension in the five-dimensional energy supply and demand deviation vector to the first threshold adjustment value or the second threshold adjustment value. The matrix is ​​constructed as follows: during the initial operation phase of the system, the five-dimensional energy supply and demand deviation vectors at multiple historical moments are recorded as the input sample matrix, and the corresponding historical threshold adjustment values ​​are recorded as the output sample matrix. The least squares method is used to solve for the matrix that minimizes the sum of squared errors between the input sample matrix and the output sample matrix, which is used as the deviation-threshold mapping matrix. This matrix is ​​used to map the five-dimensional energy supply and demand deviation vector to the first threshold adjustment value and the second threshold adjustment value.

[0031] Furthermore, the energy transfer topology building blocks include: The node calibration unit is used to calibrate the generator outlet of the first-stage absorption refrigeration unit as the first node, the desorber inlet of the second-stage adsorption refrigeration unit as the second node, the desorber outlet of the second-stage adsorption refrigeration unit as the third node, the desorber inlet of the third-stage adsorption refrigeration unit as the fourth node, and the desorber outlet of the third-stage adsorption refrigeration unit as the fifth node. A directed edge construction unit is used to construct the heat transfer path between the first node and the second node as a first directed edge, and the heat transfer path between the third node and the fourth node as a second directed edge; The node attribute assignment unit is used to assign the output cooling temperature value of the first-stage absorption refrigeration unit to the cooling output attribute of the first node, the output cooling temperature value of the second-stage adsorption refrigeration unit to the cooling output attribute of the third node, and the output cooling temperature value of the third-stage adsorption refrigeration unit to the cooling output attribute of the fifth node.

[0032] In this embodiment, the node calibration unit is used to calibrate the generator outlet of the first-stage absorption refrigeration unit as the first node, the desorber inlet of the second-stage adsorption refrigeration unit as the second node, the desorber outlet of the second-stage adsorption refrigeration unit as the third node, the desorber inlet of the third-stage adsorption refrigeration unit as the fourth node, and the desorber outlet of the third-stage adsorption refrigeration unit as the fifth node. This calibration process establishes the correspondence between the physical device locations and the nodes of the energy transfer topology, where the first node corresponds to the heat source output end, the second node corresponds to the first-stage heat source receiver end, the third node corresponds to the first-stage waste heat output end, the fourth node corresponds to the second-stage heat source receiver end, and the fifth node corresponds to the second-stage waste heat output end.

[0033] In this embodiment, the directed edge construction unit is used to construct the heat energy transfer path between the first node and the second node as a first directed edge, and the heat energy transfer path between the third node and the fourth node as a second directed edge. The first directed edge represents the directional transfer relationship of heat energy from the generator outlet of the first-stage absorption refrigeration unit to the desorber inlet of the second-stage adsorption refrigeration unit, and the second directed edge represents the directional transfer relationship of heat energy from the desorber outlet of the second-stage adsorption refrigeration unit to the desorber inlet of the tertiary adsorption refrigeration unit.

[0034] In this embodiment, the node attribute assignment unit assigns the output cooling temperature value of the first-stage absorption refrigeration unit as the cooling output attribute of the first node, assigns the output cooling temperature value of the second-stage adsorption refrigeration unit as the cooling output attribute of the third node, and assigns the output cooling temperature value of the third-stage adsorption refrigeration unit as the cooling output attribute of the fifth node. When generating the five-dimensional energy supply and demand deviation vector, the energy supply and demand deviation vector generation module uses the cooling output attribute of each node as a reference for the preset reference temperature range of that node, so that the energy supply and demand deviation vector can simultaneously reflect the dual effects of temperature deviation and cooling output deviation.

[0035] Furthermore, the energy supply-demand deviation vector generation module includes: The node temperature acquisition unit is used to acquire the real-time temperature values ​​of the first node, the second node, the third node, the fourth node, and the fifth node. The reference temperature range storage unit is used to store the preset reference temperature ranges corresponding to the first node, the second node, the third node, the fourth node, and the fifth node, wherein the preset reference temperature range of the first node is 60-80℃, the preset reference temperature range of the second node is 30-50℃, the preset reference temperature range of the third node is 30-50℃, the preset reference temperature range of the fourth node is 20-40℃, and the preset reference temperature range of the fifth node is 20-40℃. The deviation calculation unit is used to calculate the difference between the real-time temperature value of each node and the center value of the corresponding reference temperature range. The difference is divided by half the width of the reference temperature range to obtain the normalized deviation value of each node. The vector generation unit is used to arrange the normalized deviation values ​​of the first node, second node, third node, fourth node, and fifth node in the node order to generate a five-dimensional energy supply and demand deviation vector.

[0036] In this embodiment, the real-time temperature values ​​of the first node, second node, third node, fourth node, and fifth node are acquired by using a first temperature sensor located at the outlet of the first-stage absorption refrigeration unit generator, a second temperature sensor located at the inlet of the second-stage adsorption refrigeration unit desorber, a third temperature sensor located at the outlet of the second-stage adsorption refrigeration unit desorber, a fourth temperature sensor located at the inlet of the third-stage adsorption refrigeration unit desorber, and a fifth temperature sensor located at the outlet of the third-stage adsorption refrigeration unit desorber. These values ​​reflect the temperature at the heat source output end, the temperature at the first-stage heat source receiving end, the temperature at the first-stage waste heat output end, the temperature at the second-stage heat source receiving end, and the temperature at the second-stage waste heat output end, respectively.

[0037] In this embodiment, the preset reference temperature range for the first node is 60-80℃, the preset reference temperature range for the second node is 30-50℃, the preset reference temperature range for the third node is 30-50℃, the preset reference temperature range for the fourth node is 20-40℃, and the preset reference temperature range for the fifth node is 20-40℃. This means that the first node's reference temperature range is set to 60-80℃ based on the temperature fluctuation range at the outlet of the first-stage absorption refrigeration unit generator under normal operating conditions, and the second node's reference temperature range is set to 20-40℃ based on the temperature fluctuation range at the inlet of the second-stage adsorption refrigeration unit desorber under normal operating conditions. The reference temperature range is 30-50℃. Based on the temperature fluctuation range of the desorber outlet of the two-stage adsorption refrigeration unit under normal operating conditions, the reference temperature range of the third node is set to 30-50℃. Based on the temperature fluctuation range of the desorber inlet of the three-stage adsorption refrigeration unit under normal operating conditions, the reference temperature range of the fourth node is set to 20-40℃. Based on the temperature fluctuation range of the desorber outlet of the three-stage adsorption refrigeration unit under normal operating conditions, the reference temperature range of the fifth node is set to 20-40℃. These reference temperature ranges are used as reference standards to measure whether the real-time temperature value of each node deviates from the normal range.

[0038] In this embodiment, the difference between the real-time temperature value of each node and the center value of the corresponding reference temperature interval is calculated. This difference is then divided by half the width of the reference temperature interval to obtain the normalized deviation value for each node. Specifically, for each node, the average of the upper and lower limits of the reference temperature interval is first calculated as the center value. Then, the difference between the real-time temperature value of the node and the center value is calculated. This difference is then divided by half the width of the reference temperature interval to obtain the normalized deviation value for that node. The normalized deviation value is 0 when the real-time temperature value equals the center value of the reference temperature interval, 1 when the real-time temperature value equals the upper limit of the reference temperature interval, and -1 when the real-time temperature value equals the lower limit of the reference temperature interval. The normalized deviation value unifies temperature deviations of different dimensions and ranges into a range of -1 to 1, facilitating subsequent comprehensive calculations of multi-dimensional data. When calculating the normalized deviation value for each node, the deviation calculation unit increments the normalized deviation value by +1 when the real-time temperature value exceeds the upper limit of the reference temperature range; it increments it by -1 when the real-time temperature value is below the lower limit of the reference temperature range; and it calculates the normalized deviation value within the range of -1 to +1 when the real-time temperature value is within the reference temperature range. This limiting process prevents excessively large normalized deviation values ​​from causing valve adjustment value overflow when the real-time temperature value deviates significantly.

[0039] In this embodiment, the normalized deviation values ​​of the first, second, third, fourth, and fifth nodes are arranged in node order to generate a five-dimensional energy supply and demand deviation vector. This means that the normalized deviation value of the first node is used as the first component of the vector, the normalized deviation value of the second node as the second component, the normalized deviation value of the third node as the third component, the normalized deviation value of the fourth node as the fourth component, and the normalized deviation value of the fifth node as the fifth component, forming a vector containing five elements. This vector comprehensively represents the degree and direction of the current temperature deviation from the normal operating range of each key node in the entire heat transfer network from five dimensions, reflecting the overall energy supply and demand status of the system.

[0040] Furthermore, the interstage energy distribution controller includes: The deviation-threshold mapping matrix storage unit is used to store the deviation-threshold mapping matrix of the five-dimensional input and two-dimensional output. The deviation-threshold mapping matrix is ​​a 2-row, 5-column matrix. Each element in the matrix represents the contribution weight of the deviation value of the corresponding dimension to the corresponding threshold adjustment value. The matrix multiplication unit is used to multiply the five-dimensional energy supply and demand deviation vector with the deviation-valve mapping matrix to obtain a two-dimensional valve adjustment vector, which includes a first valve adjustment value and a second valve adjustment value. The valve-to-opening conversion unit is used to convert the first valve adjustment value into the opening adjustment amount of the first directed edge, and to convert the second valve adjustment value into the opening adjustment amount of the second directed edge.

[0041] In this embodiment, a deviation-threshold mapping matrix is ​​stored between the five-dimensional input and the two-dimensional output. This deviation-threshold mapping matrix is ​​a 2x5 matrix, where each element represents the contribution weight of the deviation value in the corresponding dimension to the corresponding threshold adjustment value. Specifically, a 2x5 matrix is ​​pre-constructed and stored. The rows of this matrix correspond to the first and second threshold adjustment values, and the columns correspond to the first, second, third, fourth, and fifth components of the five-dimensional energy supply and demand deviation vector. The element in the first row and first column represents the contribution weight of the first component of the five-dimensional energy supply and demand deviation vector to the first threshold adjustment value; the element in the first row and second column represents the contribution weight of the second component to the first threshold adjustment value, and so on up to the fifth element in the first row. Similarly, the element in the second row and first column represents the contribution weight of the first component to the second threshold adjustment value, and so on up to the fifth element in the second row. The matrix is ​​determined through offline learning. The specific construction method is as follows: during the initial operation phase of the system, the five-dimensional energy supply and demand deviation vectors at multiple historical moments are recorded as the input sample matrix, and the corresponding first and second threshold adjustment values ​​are recorded as the output sample matrix. The least squares method is used to solve for the 2-row, 5-column matrix that minimizes the sum of the squared errors between the input sample matrix and the output sample matrix, which is then used as the deviation-threshold mapping matrix.

[0042] In this embodiment, a two-dimensional threshold adjustment vector is obtained by multiplying the five-dimensional energy supply and demand deviation vector with the deviation-threshold mapping matrix. The two-dimensional threshold adjustment vector includes a first threshold adjustment value and a second threshold adjustment value. This is achieved by treating the five-dimensional energy supply and demand deviation vector as a 1x5 matrix and performing matrix multiplication with the 2x5 deviation-threshold mapping matrix. Specifically, the calculation process is as follows: The first threshold adjustment value equals the first component of the five-dimensional energy supply and demand deviation vector multiplied by the first element of the first row and first column of the deviation-threshold mapping matrix, plus the second component multiplied by the first element of the first row and second column, plus the third component multiplied by the first element of the first row and third column, plus the fourth component multiplied by the first element of the first row and fourth column, plus the fifth component multiplied by the first element of the first row and fifth column; the second threshold adjustment value equals the first component of the five-dimensional energy supply and demand deviation vector multiplied by the second element of the second row and first column of the deviation-threshold mapping matrix, plus the second component multiplied by the second element of the second row and second column, plus the third component multiplied by the second element of the second row and third column, plus the fourth component multiplied by the second element of the second row and fourth column, plus the fifth component multiplied by the second element of the second row and fifth column. Through this multiplication operation, the energy supply and demand deviation state in five-dimensional space is mapped to the valve adjustment command in two-dimensional space, realizing coordinated control from multi-variable input to multi-variable output.

[0043] Furthermore, the deviation-threshold mapping matrix storage unit includes: The offline learning subunit is used to record the five-dimensional energy supply and demand deviation vector and the corresponding historical threshold adjustment value at multiple historical moments during the initial operation phase of the system. The five-dimensional energy supply and demand deviation vector at multiple historical moments is used as the input sample matrix, and the corresponding historical threshold adjustment value is used as the output sample matrix. The deviation-threshold mapping matrix is ​​solved by the least squares method to minimize the sum of the squared errors of the product of the deviation-threshold mapping matrix and the input sample matrix and the output sample matrix.

[0044] In this embodiment, the offline learning subunit is used to record the five-dimensional energy supply and demand deviation vectors and corresponding historical threshold adjustment values ​​at multiple historical moments during the initial operation phase of the system. The five-dimensional energy supply and demand deviation vectors at multiple historical moments are used as the input sample matrix, and the corresponding historical threshold adjustment values ​​are used as the output sample matrix. The deviation-threshold mapping matrix is ​​solved using the least squares method to minimize the sum of squared errors between the product of the deviation-threshold mapping matrix and the input sample matrix and the output sample matrix. Specifically, assuming data from K historical moments has been collected, the K five-dimensional energy supply and demand deviation vectors are arranged in rows to form a K-row, 5-column input sample matrix, and the K two-dimensional threshold adjustment vectors are arranged in rows to form a K-row, 2-column output sample matrix. The least squares method obtains the optimal 2-row, 5-column deviation-threshold mapping matrix by solving the normal equation. This matrix minimizes the mean square error between the product of the input sample matrix and the transpose of the deviation-threshold mapping matrix and the output sample matrix. By employing the least squares method for offline learning, the optimal weight parameters of the deviation-threshold mapping matrix can be determined using historical data before the system runs, making the mapping relationship statistically optimal.

[0045] Furthermore, the deviation-threshold mapping matrix storage unit includes: The online update subunit is used to continuously record the five-dimensional energy supply and demand deviation vector and the current output threshold adjustment value during system operation. It adds the current data to the historical data set, and re-solves the deviation-threshold mapping matrix using the least squares method with the updated historical data set every preset update cycle. It calculates the difference between the re-solved deviation-threshold mapping matrix and the currently used deviation-threshold mapping matrix. When the difference is less than the preset difference threshold, the update stops and the system continues to run using the currently used deviation-threshold mapping matrix.

[0046] In this embodiment, the online update subunit continuously records the five-dimensional energy supply and demand deviation vector and the current output threshold adjustment value during system operation. It adds the current data to the historical data set. Every preset update cycle, it re-solves the deviation-threshold mapping matrix using the least squares method with the updated historical data set. It calculates the difference between the re-solved deviation-threshold mapping matrix and the currently used deviation-threshold mapping matrix. When the difference is less than a preset difference threshold, the update stops, and the system continues operation using the currently used deviation-threshold mapping matrix. Specifically, the system continuously collects new five-dimensional energy supply and demand deviation vectors and corresponding threshold adjustment values ​​during operation, appending these new data to the historical data set established during the offline learning phase, forming a continuously expanding sample set. Every preset update cycle, it re-executes the least squares method using the current complete historical data set to obtain a new deviation-threshold mapping matrix. The sum or square of the absolute values ​​of the differences between corresponding elements in the new matrix and the currently used matrix is ​​calculated as the difference degree. When the difference degree is less than a preset difference threshold, it indicates that the matrix parameters have stabilized, and updates are stopped while the current matrix continues to be used. When the difference degree is greater than or equal to the preset difference threshold, the currently used matrix is ​​replaced with the newly solved matrix, enabling the system to adapt to the drift of the optimal mapping relationship caused by changes in operating conditions. Through the online update mechanism, the system can continuously optimize the parameters of the deviation-threshold mapping matrix during operation, allowing the control model to continuously approach the optimal mapping relationship under the current operating conditions.

[0047] Furthermore, the valve degree-opening degree conversion unit includes: The opening adjustment amount calculation subunit is used to multiply the first valve adjustment value by the opening adjustment coefficient of the first directed edge to obtain the opening adjustment amount of the first directed edge, and multiply the second valve adjustment value by the opening adjustment coefficient of the second directed edge to obtain the opening adjustment amount of the second directed edge. The target opening value calculation subunit is used to add the reference opening value of the first directed edge to the opening adjustment amount of the first directed edge to obtain the target opening value of the first directed edge, and add the reference opening value of the second directed edge to the opening adjustment amount of the second directed edge to obtain the target opening value of the second directed edge. The control signal sending subunit is used to send a control signal corresponding to the first target opening value to the actuator of the first directed edge, and to send a control signal corresponding to the second target opening value to the actuator of the second directed edge.

[0048] In this embodiment, the opening adjustment coefficient of the first directed edge refers to a preset proportional constant used to convert the first valve adjustment value into the opening adjustment amount of the first directed edge. This coefficient reflects the opening change range corresponding to the unit valve adjustment value, and its specific value is predetermined based on the response characteristics of the actuator on the first directed edge.

[0049] In this embodiment, the opening adjustment coefficient of the second directed edge refers to a preset proportional constant used to convert the second valve adjustment value into the opening adjustment amount of the second directed edge. This coefficient reflects the opening change range corresponding to a unit valve adjustment value, and its specific value is predetermined based on the response characteristics of the actuator on the second directed edge.

[0050] In this embodiment, the target opening value of the first directed edge is obtained by adding the reference opening value of the first directed edge to the opening adjustment amount of the first directed edge. Similarly, the target opening value of the second directed edge is obtained by adding the reference opening value of the second directed edge to the opening adjustment amount of the second directed edge. This means that under normal operating conditions, the first and second directed edges maintain a reference opening to ensure the basic heat transfer flow rate. When the system detects an energy supply-demand deviation, the opening adjustment amount is superimposed on the reference opening value to obtain the final target opening value. Specifically, the target opening value of the first directed edge is equal to the reference opening value plus the opening adjustment amount of the first directed edge, and the target opening value of the second directed edge is equal to the reference opening value plus the opening adjustment amount of the second directed edge. When the threshold adjustment value is positive, the opening adjustment amount is positive, the target opening value is greater than the reference opening value, and the heat transfer flow rate increases. When the threshold adjustment value is negative, the opening adjustment amount is negative, the target opening value is less than the reference opening value, and the heat transfer flow rate decreases.

[0051] In this embodiment, after calculating the target opening values ​​of the first directed edge and the second directed edge, the target opening value calculation subunit performs a boundary check on the target opening value: when the target opening value is less than 0%, the target opening value is set to 0%; when the target opening value is greater than 100%, the target opening value is set to 100%. Through boundary constraints, it is ensured that the actuator always operates within a safe opening range, avoiding damage to the actuator or interruption of heat transfer due to excessive valve adjustment value.

[0052] In this embodiment, sending a control signal corresponding to the first target opening value to the actuator of the first directed edge and sending a control signal corresponding to the second target opening value to the actuator of the second directed edge means converting the first target opening value into a control signal and sending it to the actuator of the first directed edge, and converting the second target opening value into a control signal and sending it to the actuator of the second directed edge. The actuator adjusts its opening according to the received control signal so that the actual opening of the first and second directed edges reaches the target opening value, thereby achieving precise regulation of the heat transfer flow rate.

[0053] Furthermore, the reference opening value of the first directed edge and the reference opening value of the second directed edge are determined in the following manner: Obtain the standard cooling capacity requirements for the interstage cooling stage of carbon dioxide compression and the standard cooling capacity requirements for the pre-cooling stage of carbon dioxide liquefaction in the CCUS system. Based on the standard cooling capacity requirement of the carbon dioxide compression interstage cooling stage and the rated output cooling capacity of the first-stage absorption refrigeration unit, the heat energy required to be provided by the generator outlet of the first-stage absorption refrigeration unit is determined, and then the reference opening value of the first directed edge is determined. Based on the standard cooling capacity requirement of the carbon dioxide liquefaction precooling stage and the rated output cooling capacity of the secondary adsorption refrigeration unit, the heat energy that the desorber of the secondary adsorption refrigeration unit needs to absorb is determined, and then the reference opening value of the second directed edge is determined.

[0054] In this embodiment, the CCUS system refers to a carbon dioxide capture, utilization and storage system. This system includes multiple process steps such as carbon dioxide compression, liquefaction, transportation, storage or utilization. Among them, the interstage cooling stage of carbon dioxide compression and the pre-cooling stage of carbon dioxide liquefaction require cooling energy and are the cooling energy supply objects of the low-temperature heat source refrigeration system of the present invention.

[0055] In this embodiment, the interstage cooling stage of carbon dioxide compression refers to the process in the carbon dioxide capture, utilization and storage system where, when carbon dioxide gas is compressed by a multi-stage compressor, a cooler is set between each stage of compression to cool the high-temperature carbon dioxide gas. This stage requires 3-10°C of cooling to reduce compression power consumption and prevent the equipment from overheating.

[0056] In this embodiment, the standard cooling capacity requirement of the carbon dioxide compression stage cooling link refers to the cooling capacity required by the carbon dioxide capture and storage system under rated operating conditions for the carbon dioxide compression stage cooling link. This value is predetermined based on process parameters such as carbon dioxide throughput, number of compressor stages, and inlet temperature, and is used as a target reference value for the output cooling capacity of the first-stage absorption refrigeration unit.

[0057] In this embodiment, the carbon dioxide liquefaction precooling step refers to the process of pre-cooling carbon dioxide gas before deep liquefaction in the carbon dioxide capture, utilization and storage system. This step requires a cooling capacity of -15°C to -30°C to reduce the energy consumption of subsequent deep liquefaction and improve liquefaction efficiency.

[0058] In this embodiment, the standard cooling capacity requirement for the carbon dioxide liquefaction precooling stage refers to the cooling capacity required by the carbon dioxide capture and storage system under rated operating conditions for the carbon dioxide liquefaction precooling stage. This value is predetermined based on process parameters such as carbon dioxide processing capacity and precooling target temperature, and is used as a target reference value for the output cooling capacity of the secondary adsorption refrigeration unit.

[0059] In this embodiment, obtaining the standard cooling capacity requirement values ​​for the interstage cooling stage of carbon dioxide compression and the precooling stage of carbon dioxide liquefaction in the CCUS system refers to reading the pre-set cooling capacity values ​​required for the interstage cooling stage of carbon dioxide compression and the precooling stage of carbon dioxide liquefaction from the process parameter database of the carbon dioxide capture, utilization and storage system. These standard cooling capacity requirement values ​​reflect the downstream process's expected cooling capacity output of the refrigeration system and are the basis for determining the reference opening values ​​of the first and second directed edges.

[0060] In this embodiment, the rated output cooling capacity of the primary absorption refrigeration unit refers to the cooling capacity that the primary absorption refrigeration unit can stably output under design conditions. This value is determined by parameters such as the model, specifications, and working fluid charge of the primary absorption refrigeration unit, and reflects the standard cooling capacity output capability of the refrigeration unit under given driving heat source conditions.

[0061] In this embodiment, based on the standard cooling capacity requirement of the interstage cooling stage of carbon dioxide compression and the rated output cooling capacity of the first-stage absorption refrigeration unit, the thermal energy required to be provided by the generator outlet of the first-stage absorption refrigeration unit is determined. Then, the reference opening value of the first directed edge is determined by dividing the standard cooling capacity requirement of the interstage cooling stage of carbon dioxide compression by the rated output cooling capacity of the first-stage absorption refrigeration unit, thus obtaining the required load rate of the first-stage absorption refrigeration unit. Based on this load rate, the thermal energy required to be provided by the generator outlet of the first-stage absorption refrigeration unit is calculated. This thermal energy value determines the thermal energy flow rate that the first directed edge needs to transfer. Through the physical relationship between the actuator opening on the first directed edge and the thermal energy transfer flow rate, this thermal energy value is mapped to the reference opening value of the first directed edge.

[0062] In this embodiment, the rated output cooling capacity of the two-stage adsorption refrigeration unit refers to the cooling capacity that the two-stage adsorption refrigeration unit can stably output under the design operating conditions. This value is determined by the model, specifications, adsorbent and refrigerant working fluid of the two-stage adsorption refrigeration unit, and reflects the standard cooling capacity output capability of the refrigeration unit under a given driving heat source condition.

[0063] In this embodiment, based on the standard cooling capacity requirement of the carbon dioxide liquefaction precooling stage and the rated output cooling capacity of the secondary adsorption refrigeration unit, the heat energy that the desorber of the secondary adsorption refrigeration unit needs to absorb is determined. Then, the reference opening value of the second directed edge is determined by dividing the standard cooling capacity requirement of the carbon dioxide liquefaction precooling stage by the rated output cooling capacity of the secondary adsorption refrigeration unit, thus obtaining the required load rate of the secondary adsorption refrigeration unit. Based on this load rate, the heat energy that the desorber of the secondary adsorption refrigeration unit needs to absorb is calculated. This heat energy value determines the heat energy flow rate that the second directed edge needs to transfer. Through the physical relationship between the opening of the actuator on the second directed edge and the heat energy transfer flow rate, this heat energy value is mapped to the reference opening value of the second directed edge.

[0064] Furthermore, it also includes: The temperature difference calculation module is used to collect the real-time temperature value of the generator outlet of the first-stage absorption refrigeration unit and the real-time temperature value of the desorber inlet of the second-stage adsorption refrigeration unit, calculate the temperature difference between the two ends of the first directed edge, collect the real-time temperature value of the desorber outlet of the second-stage adsorption refrigeration unit and the real-time temperature value of the desorber inlet of the third-stage adsorption refrigeration unit, and calculate the temperature difference between the two ends of the second directed edge. The priority switching module is used to decrease the first threshold adjustment value and increase the second threshold adjustment value when the temperature difference between the two ends of the first directed edge is less than the first temperature difference threshold, and decrease the second threshold adjustment value and increase the first threshold adjustment value when the temperature difference between the two ends of the second directed edge is less than the second temperature difference threshold.

[0065] In this embodiment, the real-time temperature values ​​at the outlet of the primary absorption refrigeration unit generator and the inlet of the secondary adsorption refrigeration unit desorber are collected to calculate the temperature difference between the two ends of the first directed edge. Similarly, the real-time temperature values ​​at the outlet of the secondary adsorption refrigeration unit desorber and the inlet of the tertiary adsorption refrigeration unit desorber are collected to calculate the temperature difference between the two ends of the second directed edge. This is achieved by subtracting the real-time temperature values ​​at the outlet of the primary absorption refrigeration unit generator obtained by the first temperature sensor and the inlet of the secondary adsorption refrigeration unit desorber obtained by the second temperature sensor. Finally, the real-time temperature values ​​at the outlet of the secondary adsorption refrigeration unit desorber and the inlet of the tertiary adsorption refrigeration unit desorber obtained by the third temperature sensor and the inlet of the tertiary adsorption refrigeration unit desorber obtained by the fourth temperature sensor are subtracted to obtain the temperature difference between the two ends of the second directed edge.

[0066] In this embodiment, the first temperature difference threshold is a pre-set critical value used to determine whether the temperature difference between the two ends of the first directed edge is too small. This threshold is determined based on the minimum allowable temperature difference between the two ends of the first directed edge. When the temperature difference between the two ends of the first directed edge is less than this threshold, it indicates that the heat transfer efficiency of the first directed edge is close to its limit. Continuing to increase the heat transfer flow rate of the first directed edge has limited effect on improving the overall energy efficiency of the system, and the adjustment resources should be preferentially allocated to the second directed edge.

[0067] In this embodiment, when the temperature difference between the two ends of the first directed edge is less than the first temperature difference threshold, reducing the first threshold adjustment value and increasing the second threshold adjustment value means that when the temperature difference between the two ends of the first directed edge is less than the first temperature difference threshold, the heat transfer flow rate adjustment intensity of the first directed edge is reduced by decreasing the first threshold adjustment value, and the heat transfer flow rate adjustment intensity of the second directed edge is increased by increasing the second threshold adjustment value. The adjustment resources are transferred from the first directed edge to the second directed edge, avoiding the waste of energy caused by continuing to increase the heat transfer flow rate when the temperature difference between the two ends of the first directed edge is too small. At the same time, the adjustment resources are used to improve the heat supply and demand matching state of the second directed edge.

[0068] In this embodiment, the second temperature difference threshold is a pre-set critical value used to determine whether the temperature difference between the two ends of the second directed edge is too small. This threshold is determined based on the minimum allowable temperature difference between the two ends of the second directed edge. When the temperature difference between the two ends of the second directed edge is less than this threshold, it indicates that the heat transfer efficiency of the second directed edge is close to its limit. Continuing to increase the heat transfer flow rate of the second directed edge has limited effect on improving the overall energy efficiency of the system, and the adjustment resources should be preferentially allocated to the first directed edge.

[0069] In this embodiment, when the temperature difference between the two ends of the second directed edge is less than the second temperature difference threshold, decreasing the second threshold adjustment value and increasing the first threshold adjustment value means that when the temperature difference between the two ends of the second directed edge is less than the second temperature difference threshold, the heat transfer flow regulation intensity of the second directed edge is reduced by decreasing the second threshold adjustment value, while the heat transfer flow regulation intensity of the first directed edge is increased by increasing the first threshold adjustment value. This transfers regulation resources from the second directed edge to the first directed edge, preventing energy waste caused by further increasing the heat transfer flow when the temperature difference between the two ends of the second directed edge is too small. Simultaneously, the regulation resources are used to improve the heat supply and demand matching state of the first directed edge. This mechanism, together with the regulation priority switching mechanism of the first directed edge, constitutes a two-sided dynamic regulation resource allocation strategy, enabling the system to adaptively allocate regulation resources between the two heat transfer paths, prioritizing the allocation of regulation resources to paths with larger temperature differences and greater regulation potential.

[0070] This invention provides an embodiment of a low-temperature heat source refrigeration method, comprising: The generator outlet of the first-stage absorption refrigeration unit, the desorber inlet of the second-stage adsorption refrigeration unit, the desorber outlet of the second-stage adsorption refrigeration unit, the desorber inlet of the third-stage adsorption refrigeration unit, and the desorber outlet of the third-stage adsorption refrigeration unit are constructed as an energy transfer topology graph containing five nodes. The heat energy transfer path between the generator outlet of the first-stage absorption refrigeration unit and the desorber inlet of the second-stage adsorption refrigeration unit is constructed as a first directed edge, and the heat energy transfer path between the desorber outlet of the second-stage adsorption refrigeration unit and the desorber inlet of the third-stage adsorption refrigeration unit is constructed as a second directed edge. The output cooling capacity of each refrigeration unit is constructed as the cooling capacity output attribute of the outlet node of each refrigeration unit. Collect the real-time temperature values ​​of each node in the energy transfer topology diagram, and generate a five-dimensional energy supply and demand deviation vector with five nodes as the dimensions based on the deviation between the real-time temperature values ​​of each node and the preset reference temperature range of each node. The five-dimensional energy supply and demand deviation vector is input into the preset deviation-valve mapping matrix. The first valve adjustment value corresponding to the first directed edge and the second valve adjustment value corresponding to the second directed edge are calculated through the deviation-valve mapping matrix. The heat transfer flow rate of the first directed edge and the second directed edge is adjusted according to the first valve adjustment value and the second valve adjustment value, respectively.

[0071] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of this invention and its equivalents, this invention also intends to include these modifications and variations.

Claims

1. A low-temperature heat source refrigeration system, characterized in that, include: The energy transfer topology construction module is used to construct an energy transfer topology graph containing five nodes, consisting of the generator outlet of the first-stage absorption refrigeration unit, the desorber inlet of the second-stage adsorption refrigeration unit, the desorber outlet of the second-stage adsorption refrigeration unit, the desorber inlet of the third-stage adsorption refrigeration unit, and the desorber outlet of the third-stage adsorption refrigeration unit. The heat energy transfer path between the generator outlet of the first-stage absorption refrigeration unit and the desorber inlet of the second-stage adsorption refrigeration unit is constructed as the first directed edge, and the heat energy transfer path between the desorber outlet of the second-stage adsorption refrigeration unit and the desorber inlet of the third-stage adsorption refrigeration unit is constructed as the second directed edge. The output cooling capacity of each refrigeration unit is constructed as the cooling capacity output attribute of the outlet node of each refrigeration unit. The energy supply and demand deviation vector generation module is used to collect the real-time temperature values ​​of each node in the energy transfer topology diagram, and generate a five-dimensional energy supply and demand deviation vector with five nodes as the dimensions based on the deviation between the real-time temperature values ​​of each node and the preset reference temperature range of each node. The interstage energy distribution controller is used to input the five-dimensional energy supply and demand deviation vector into a preset deviation-valve mapping matrix, calculate the first valve adjustment value corresponding to the first directed edge and the second valve adjustment value corresponding to the second directed edge through the deviation-valve mapping matrix, and adjust the heat transfer flow rate of the first directed edge and the second directed edge according to the first valve adjustment value and the second valve adjustment value respectively.

2. The low-temperature heat source refrigeration system according to claim 1, characterized in that, The energy transfer topology building blocks include: The node calibration unit is used to calibrate the generator outlet of the first-stage absorption refrigeration unit as the first node, the desorber inlet of the second-stage adsorption refrigeration unit as the second node, the desorber outlet of the second-stage adsorption refrigeration unit as the third node, the desorber inlet of the third-stage adsorption refrigeration unit as the fourth node, and the desorber outlet of the third-stage adsorption refrigeration unit as the fifth node. A directed edge construction unit is used to construct the heat transfer path between the first node and the second node as a first directed edge, and the heat transfer path between the third node and the fourth node as a second directed edge; The node attribute assignment unit is used to assign the output cooling temperature value of the first-stage absorption refrigeration unit to the cooling output attribute of the first node, the output cooling temperature value of the second-stage adsorption refrigeration unit to the cooling output attribute of the third node, and the output cooling temperature value of the third-stage adsorption refrigeration unit to the cooling output attribute of the fifth node.

3. The low-temperature heat source refrigeration system according to claim 1, characterized in that, The energy supply and demand deviation vector generation module includes: The node temperature acquisition unit is used to acquire the real-time temperature values ​​of the first node, the second node, the third node, the fourth node, and the fifth node. The reference temperature range storage unit is used to store the preset reference temperature ranges corresponding to the first node, the second node, the third node, the fourth node, and the fifth node, wherein the preset reference temperature range of the first node is 60-80℃, the preset reference temperature range of the second node is 30-50℃, the preset reference temperature range of the third node is 30-50℃, the preset reference temperature range of the fourth node is 20-40℃, and the preset reference temperature range of the fifth node is 20-40℃. The deviation calculation unit is used to calculate the difference between the real-time temperature value of each node and the center value of the corresponding reference temperature range. The difference is divided by half the width of the reference temperature range to obtain the normalized deviation value of each node. The vector generation unit is used to arrange the normalized deviation values ​​of the first node, second node, third node, fourth node, and fifth node in the node order to generate a five-dimensional energy supply and demand deviation vector.

4. The low-temperature heat source refrigeration system according to claim 1, characterized in that, The interstage energy distribution controller includes: The deviation-threshold mapping matrix storage unit is used to store the deviation-threshold mapping matrix of the five-dimensional input and two-dimensional output. The deviation-threshold mapping matrix is ​​a 2-row, 5-column matrix. Each element in the matrix represents the contribution weight of the deviation value of the corresponding dimension to the corresponding threshold adjustment value. The matrix multiplication unit is used to multiply the five-dimensional energy supply and demand deviation vector with the deviation-valve mapping matrix to obtain a two-dimensional valve adjustment vector, which includes a first valve adjustment value and a second valve adjustment value. The valve-to-opening conversion unit is used to convert the first valve adjustment value into the opening adjustment amount of the first directed edge, and to convert the second valve adjustment value into the opening adjustment amount of the second directed edge.

5. The low-temperature heat source refrigeration system according to claim 4, characterized in that, The deviation-threshold mapping matrix storage unit includes: The offline learning subunit is used to record the five-dimensional energy supply and demand deviation vector and the corresponding historical threshold adjustment value at multiple historical moments during the initial operation phase of the system. The five-dimensional energy supply and demand deviation vector at multiple historical moments is used as the input sample matrix, and the corresponding historical threshold adjustment value is used as the output sample matrix. The deviation-threshold mapping matrix is ​​solved by the least squares method to minimize the sum of the squared errors of the product of the deviation-threshold mapping matrix and the input sample matrix and the output sample matrix.

6. The low-temperature heat source refrigeration system according to claim 4, characterized in that, The deviation-threshold mapping matrix storage unit includes: The online update subunit is used to continuously record the five-dimensional energy supply and demand deviation vector and the current output threshold adjustment value during system operation. It adds the current data to the historical data set, and re-solves the deviation-threshold mapping matrix using the least squares method with the updated historical data set every preset update cycle. It calculates the difference between the re-solved deviation-threshold mapping matrix and the currently used deviation-threshold mapping matrix. When the difference is less than the preset difference threshold, the update stops and the system continues to run using the currently used deviation-threshold mapping matrix.

7. The low-temperature heat source refrigeration system according to claim 4, characterized in that, The valve degree-opening degree conversion unit includes: The opening adjustment amount calculation subunit is used to multiply the first valve adjustment value by the opening adjustment coefficient of the first directed edge to obtain the opening adjustment amount of the first directed edge, and multiply the second valve adjustment value by the opening adjustment coefficient of the second directed edge to obtain the opening adjustment amount of the second directed edge. The target opening value calculation subunit is used to add the reference opening value of the first directed edge to the opening adjustment amount of the first directed edge to obtain the target opening value of the first directed edge, and add the reference opening value of the second directed edge to the opening adjustment amount of the second directed edge to obtain the target opening value of the second directed edge. The control signal sending subunit is used to send a control signal corresponding to the first target opening value to the actuator of the first directed edge, and to send a control signal corresponding to the second target opening value to the actuator of the second directed edge.

8. The low-temperature heat source refrigeration system according to claim 7, characterized in that, The reference aperture values ​​of the first directed edge and the second directed edge are determined in the following way: Obtain the standard cooling capacity requirements for the interstage cooling stage of carbon dioxide compression and the standard cooling capacity requirements for the pre-cooling stage of carbon dioxide liquefaction in the CCUS system. Based on the standard cooling capacity requirement of the carbon dioxide compression interstage cooling stage and the rated output cooling capacity of the first-stage absorption refrigeration unit, the heat energy required to be provided by the generator outlet of the first-stage absorption refrigeration unit is determined, and then the reference opening value of the first directed edge is determined. Based on the standard cooling capacity requirement of the carbon dioxide liquefaction precooling stage and the rated output cooling capacity of the secondary adsorption refrigeration unit, the heat energy that the desorber of the secondary adsorption refrigeration unit needs to absorb is determined, and then the reference opening value of the second directed edge is determined.

9. The low-temperature heat source refrigeration system according to claim 1, characterized in that, Also includes: The temperature difference calculation module is used to collect the real-time temperature value of the generator outlet of the first-stage absorption refrigeration unit and the real-time temperature value of the desorber inlet of the second-stage adsorption refrigeration unit, calculate the temperature difference between the two ends of the first directed edge, collect the real-time temperature value of the desorber outlet of the second-stage adsorption refrigeration unit and the real-time temperature value of the desorber inlet of the third-stage adsorption refrigeration unit, and calculate the temperature difference between the two ends of the second directed edge. The priority switching module is used to decrease the first threshold adjustment value and increase the second threshold adjustment value when the temperature difference between the two ends of the first directed edge is less than the first temperature difference threshold, and decrease the second threshold adjustment value and increase the first threshold adjustment value when the temperature difference between the two ends of the second directed edge is less than the second temperature difference threshold.

10. A method for cooling with a low-temperature heat source, characterized in that, include: The generator outlet of the first-stage absorption refrigeration unit, the desorber inlet of the second-stage adsorption refrigeration unit, the desorber outlet of the second-stage adsorption refrigeration unit, the desorber inlet of the third-stage adsorption refrigeration unit, and the desorber outlet of the third-stage adsorption refrigeration unit are constructed as an energy transfer topology graph containing five nodes. The heat energy transfer path between the generator outlet of the first-stage absorption refrigeration unit and the desorber inlet of the second-stage adsorption refrigeration unit is constructed as a first directed edge, and the heat energy transfer path between the desorber outlet of the second-stage adsorption refrigeration unit and the desorber inlet of the third-stage adsorption refrigeration unit is constructed as a second directed edge. The output cooling capacity of each refrigeration unit is constructed as the cooling capacity output attribute of the outlet node of each refrigeration unit. Collect the real-time temperature values ​​of each node in the energy transfer topology diagram, and generate a five-dimensional energy supply and demand deviation vector with five nodes as the dimensions based on the deviation between the real-time temperature values ​​of each node and the preset reference temperature range of each node. The five-dimensional energy supply and demand deviation vector is input into the preset deviation-valve mapping matrix. The first valve adjustment value corresponding to the first directed edge and the second valve adjustment value corresponding to the second directed edge are calculated through the deviation-valve mapping matrix. The heat transfer flow rate of the first directed edge and the second directed edge is adjusted according to the first valve adjustment value and the second valve adjustment value, respectively.

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