Refrigeration system control method, refrigeration control system and refrigeration system

Abstract

The application provides a refrigeration system control method, a refrigeration control system and a refrigeration system. The refrigeration system control method is used for controlling the refrigeration system. The refrigeration system control method comprises the following steps: acquiring a current gas delivery amount of the refrigeration system; determining a target superheat degree of the refrigeration system according to the current gas delivery amount; and controlling the refrigeration system to operate at the target superheat degree. Controlling the refrigeration system to operate at the superheat degree corresponding to the current gas delivery amount can make the superheat degree of the refrigeration system change with the current gas delivery amount, so that the evaporation temperature of the refrigeration system can be adapted to the current gas delivery amount, thereby improving the refrigeration capacity, improving the energy efficiency of the refrigeration system and saving energy.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of refrigeration, and in particular to a refrigeration system control method, a refrigeration control system and a refrigeration system. BACKGROUND

[0002] Generally, a refrigeration system works at a rated target superheat. However, when the refrigeration system does not run at a maximum gas delivery, the rated target superheat is still used, which can result in a too low evaporation temperature of a heat exchanger, a low refrigeration capacity and a low energy efficiency of the refrigeration system, and thus affect the performance of the refrigeration system. SUMMARY

[0003] The present application provides a refrigeration system control method, a refrigeration control system and a refrigeration system with high energy efficiency.

[0004] The present application provides a refrigeration system control method for controlling a refrigeration system, the refrigeration system control method comprising:

[0005] obtaining a current gas delivery of the refrigeration system;

[0006] determining a target superheat of the refrigeration system according to the current gas delivery;

[0007] controlling the refrigeration system to run at the target superheat.

[0008] Optionally, the determining of the target superheat of the refrigeration system according to the current gas delivery comprises:

[0009] obtaining an optimal superheat corresponding to a maximum gas delivery of the refrigeration system;

[0010] determining the target superheat of the refrigeration system according to a square of a ratio of the current gas delivery to the maximum gas delivery, the optimal superheat and a minimum superheat.

[0011] Optionally, the determining of the target superheat of the refrigeration system according to the current gas delivery comprises:

[0012] obtaining an optimal superheat corresponding to a maximum gas delivery of the refrigeration system;

[0013] determining the target superheat of the refrigeration system according to a ratio of the current gas delivery to the maximum gas delivery, the optimal superheat and a minimum superheat.

[0014] Optionally, before the obtaining of the current gas delivery of the refrigeration system, the method comprises:

[0015] controlling the refrigeration system to run at the optimal superheat for a first time length when the refrigeration system is started.

[0016] Optionally, controlling the refrigeration system to operate at the target superheat includes:

[0017] If the current gas delivery rate is not the maximum gas delivery rate, the refrigeration system is controlled to operate for a second duration at the optimal superheat.

[0018] After a second period of time, the refrigeration system is controlled to operate at the target superheat.

[0019] Optionally, controlling the refrigeration system to operate at the target superheat includes:

[0020] The superheat of the refrigeration system is controlled to decrease from the optimal superheat in stages to the target superheat.

[0021] Optionally, determining the target superheat of the refrigeration system based on the current gas supply includes:

[0022] Obtain the optimal superheat corresponding to the maximum gas delivery rate of the refrigeration system;

[0023] Obtain the superheat offset value of the refrigeration system, and determine the difference between the optimal superheat and the superheat offset value as the target superheat.

[0024] Optionally, the target superheat includes multiple different partial gas delivery volume target superheat corresponding to partial gas delivery volumes;

[0025] Determining the target superheat of the refrigeration system based on the current gas supply includes:

[0026] If the current gas delivery volume is a partial gas delivery volume, the target superheat of the partial gas delivery volume corresponding to the current gas delivery volume is determined according to the mapping relationship between the multiple partial gas delivery volumes and the target superheat of the multiple partial gas delivery volumes.

[0027] Optionally, determining the target superheat of the refrigeration system based on the current gas supply includes:

[0028] The target superheat is determined based on the functional relationship between the gas supply and the superheat, wherein the relationship between the gas supply and the superheat is a linear functional relationship.

[0029] Optionally, determining the target superheat based on the relationship between gas delivery rate and superheat includes:

[0030] Based on the functional relationship between the superheat and the gas supply volume, the maximum gas supply volume of the refrigeration system, and the minimum gas supply volume of the refrigeration system, the value of the superheat corresponding to the gas supply volume is determined as the target superheat. The superheat is directly proportional to the difference between the gas supply volume and the minimum gas supply volume, directly proportional to the difference between the maximum superheat and the minimum superheat of the refrigeration system, and inversely proportional to the difference between the maximum gas supply volume and the minimum gas supply volume.

[0031] Optionally, the refrigeration system includes a compressor, which is a screw compressor.

[0032] Optionally, the refrigeration system includes a compressor.

[0033] The step of obtaining the current gas supply of the refrigeration system includes:

[0034] Obtain the current data of the compressor speed;

[0035] Determining the target superheat of the refrigeration system based on the relationship between gas delivery volume and superheat includes:

[0036] The target superheat is determined based on the functional relationship between the superheat and the compressor speed, the maximum speed and the minimum speed of the compressor. The superheat is directly proportional to the difference between the current data of the compressor speed and the minimum speed, directly proportional to the difference between the maximum superheat and the minimum superheat of the refrigeration system, and inversely proportional to the difference between the maximum speed and the minimum speed.

[0037] Optionally, the compressor is a variable frequency compressor.

[0038] Optionally, the refrigeration system includes a compressor, and determining the target superheat of the refrigeration system includes:

[0039] Obtain the current gas delivery density of the compressor;

[0040] The target superheat of the refrigeration system is determined based on the current gas delivery density and the maximum gas delivery density of the compressor.

[0041] Optionally, determining the target superheat of the refrigeration system based on the current gas delivery density and the maximum gas delivery density of the compressor includes:

[0042] Obtain the optimal superheat and the maximum gas density corresponding to the maximum gas delivery volume of the refrigeration system;

[0043] The target superheat of the refrigeration system is determined based on the ratio of the maximum gas delivery density to the current gas delivery density and the optimal superheat.

[0044] Optionally, determining the target superheat of the refrigeration system based on the current gas delivery density and the maximum gas delivery density of the compressor includes:

[0045] The target superheat of the refrigeration system is determined based on the square of the ratio of the current gas delivery volume to the maximum gas delivery volume, the ratio of the maximum gas delivery density to the current gas delivery density, the optimal superheat, and the minimum superheat.

[0046] Optionally, determining the target superheat of the refrigeration system based on the current gas delivery density and the maximum gas delivery density of the compressor includes:

[0047] The target superheat of the refrigeration system is determined based on the ratio of the current gas delivery volume to the maximum gas delivery volume, the ratio of the maximum gas delivery density to the current gas delivery density, the optimal superheat, and the minimum superheat.

[0048] Optionally, the compressor includes an air intake, and obtaining the current gas delivery density of the compressor includes:

[0049] Determine the pressure and temperature at the intake port;

[0050] The current gas delivery density of the compressor is determined based on the pressure and temperature at the intake port.

[0051] Optionally, the refrigeration system includes an evaporator connected to the compressor, and determining the pressure at the suction port includes:

[0052] The pressure at the suction port is determined based on the saturation pressure corresponding to the temperature at the center of the evaporator.

[0053] Optionally, the refrigeration system includes an evaporator, and determining the target superheat of the refrigeration system includes:

[0054] When the rate of change of the distribution effect-related parameters is within the set range, the current inlet flow rate of the evaporator is obtained; the distribution effect-related parameters characterize the pipeline flow distribution effect of the evaporator.

[0055] Obtain the optimal inlet flow rate of the evaporator when the pipeline flow distribution effect of the evaporator is optimal, as characterized by the relevant parameters of the distribution effect.

[0056] The target superheat of the refrigeration system is determined based on the current inlet flow rate and the optimal inlet flow rate.

[0057] Optionally, determining the target superheat of the refrigeration system based on the current flow rate and the optimal flow rate includes:

[0058] Obtain the maximum inlet velocity of the evaporator corresponding to the maximum gas delivery volume of the refrigeration system;

[0059] The target superheat of the refrigeration system is determined based on the difference between the maximum inlet flow rate and the optimal inlet flow rate, and the difference between the current inlet flow rate and the optimal inlet flow rate.

[0060] Optionally, the refrigeration system includes a compressor and a regulating valve connected between the evaporator and the compressor, and the step of obtaining the current inlet flow rate of the evaporator includes:

[0061] The current inlet flow rate of the evaporator is obtained based on the compressor's flow rate, suction density, suction pressure, and the inlet temperature of the regulating valve.

[0062] Optionally, the refrigeration system includes a compressor and a regulating valve connected between the evaporator and the compressor, and the step of obtaining the current flow rate of the evaporator includes:

[0063] The current inlet flow rate of the evaporator is obtained based on the compressor's flow rate, suction density, suction pressure, the regulating valve's inlet temperature, outlet temperature, inlet flow rate, and outlet flow rate.

[0064] Optionally, the refrigeration system includes a connected compressor and an evaporator, and determining the target superheat of the refrigeration system includes:

[0065] Obtain the current gas delivery density of the compressor;

[0066] When the rate of change of the distribution effect-related parameters is within the set range, the current inlet flow rate of the evaporator is obtained; the distribution effect-related parameters characterize the pipeline flow distribution effect of the evaporator.

[0067] Obtain the optimal inlet flow rate of the evaporator when the pipeline flow distribution effect of the evaporator is optimal, as characterized by the relevant parameters of the distribution effect.

[0068] The target superheat of the refrigeration system is determined based on the current gas delivery density, the maximum gas delivery density of the compressor, the current inlet flow rate, and the optimal inlet flow rate.

[0069] Optionally, the refrigeration system includes a compressor, which includes multiple constant-speed positive displacement compressors; obtaining the current gas delivery rate of the refrigeration system includes:

[0070] Obtain the sum of the gas delivery volumes of the plurality of constant-speed positive displacement compressors.

[0071] Optionally, the refrigeration system includes a compressor, and the compressor includes a variable speed positive displacement compressor; obtaining the current gas delivery rate of the refrigeration system includes:

[0072] Obtain the product of the displacement and the rotational speed of the variable speed positive displacement compressor.

[0073] Optionally, the refrigeration system includes a compressor, and the compressor includes a screw compressor; obtaining the current gas delivery rate of the refrigeration system includes:

[0074] Obtain the maximum gas delivery capacity of the screw compressor;

[0075] Obtain the position percentage of the slide valve of the screw compressor;

[0076] Obtain the product of the position percentage of the slide valve and the maximum gas delivery volume.

[0077] This application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the refrigeration system control method as described in any of the preceding claims.

[0078] This application provides a refrigeration control system, including one or more processors, for executing the refrigeration system control method as described in any of the preceding claims.

[0079] This application also provides a refrigeration system, including the refrigeration control system described above.

[0080] In some embodiments, the target superheat of the refrigeration system is determined based on the current gas supply of the refrigeration system, and the refrigeration system is controlled to operate at the superheat corresponding to the current gas supply. This allows the superheat of the refrigeration system to change with the change in the current gas supply, so that the evaporation temperature of the refrigeration system can be adapted to the current gas supply, thereby increasing the cooling capacity, improving the energy efficiency of the refrigeration system, and saving energy.

[0081] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0082] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0083] Figure 1 The diagram shown is a schematic block diagram of one embodiment of the refrigeration system of this application.

[0084] Figure 2 The diagram shown is a flowchart of one embodiment of the refrigeration system control method of this application.

[0085] Figure 3 The diagram shown is a flowchart of another embodiment of the refrigeration system control method of this application.

[0086] Figure 4 The results shown are the test results of the refrigeration system of this application operating under different superheat conditions.

[0087] Figure 5 The diagram shown is a schematic block diagram of one embodiment of the refrigeration control system provided in this application.

[0088] Figure 6 The figure shows test data of a refrigeration system that uses the refrigeration system control method of this application. Detailed Implementation

[0089] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0090] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to limit the application. Unless otherwise defined, the technical or scientific terms used in this application should be understood in their ordinary sense by one of ordinary skill in the art to which this application pertains. The terms "first," "second," and similar terms used in this application specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms "a" or "one," etc., do not indicate a quantity limitation, but rather indicate the presence of at least one. "A plurality" or "several" indicates two or more. Unless otherwise indicated, the terms "front," "rear," "lower," and / or "upper," etc., are for ease of description only and are not limited to a location or spatial orientation. The terms "comprising" or "including," etc., mean that the elements or objects preceding "comprising" or "including" encompass the elements or objects listed following "comprising" or "including" and their equivalents, and do not exclude other elements or objects. The terms "connected," "linked," etc., are not limited to physical or mechanical connections and can include electrical connections, whether direct or indirect.

[0091] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a,” “the,” and “the” used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0092] The refrigeration system control method of this application embodiment is used to control a refrigeration system. The refrigeration system control method includes: acquiring the current gas supply volume of the refrigeration system; determining the target superheat of the refrigeration system based on the current gas supply volume; and controlling the refrigeration system to operate at the target superheat. By determining the target superheat of the refrigeration system based on the current gas supply volume and controlling the refrigeration system to operate at the superheat corresponding to the current gas supply volume, the superheat of the refrigeration system changes with the change in the current gas supply volume. This allows the evaporation temperature of the refrigeration system to adapt to the current gas supply volume, thereby increasing the cooling capacity, improving the energy efficiency of the refrigeration system, and saving energy.

[0093] This application provides a refrigeration system control method, a refrigeration control system, and a refrigeration system. The refrigeration system control method, refrigeration control system, and refrigeration system of this application will be described in detail below with reference to the accompanying drawings. Unless otherwise specified, the features in the following embodiments and implementations can be combined with each other.

[0094] Figure 1 The diagram shown is a schematic block diagram of one embodiment of the refrigeration system of this application. Figure 1 As shown, the refrigeration system includes a compressor 11, a heat exchanger 14, and a refrigeration control system 15. The heat exchanger 14 is connected to the compressor 11. The heat exchanger 14 includes a condenser 12 and an evaporator 16. The condenser 12 is connected to the outlet of the compressor 11, and the evaporator 16 is connected to the suction port of the compressor 11. The refrigeration system also includes a regulating valve 13, which is connected to the outlet of the compressor 11. The regulating valve 13 can be an expansion valve. The compressor 11 compresses the low-temperature, low-pressure gaseous refrigerant into a high-temperature, high-pressure gaseous refrigerant. The high-temperature, high-pressure gaseous refrigerant enters the condenser 12, where it exchanges heat with the outdoor airflow. The refrigerant releases heat, which is carried by the airflow into the outdoor ambient air. The refrigerant then undergoes a phase change and condenses into a liquid or gas-liquid two-phase refrigerant. The refrigerant flows out of the condenser 12, enters the regulating valve 13, expands, and cools and depressurizes, becoming a low-temperature, low-pressure refrigerant. Low-temperature, low-pressure refrigerant enters the evaporator 16, where it evaporates and absorbs heat. The refrigerant undergoes a phase change and evaporates into a low-temperature, low-pressure gaseous refrigerant, which then flows back into the compressor 11, thus achieving the recycling of the refrigerant.

[0095] A high superheat in the refrigeration system will lower the evaporation temperature of heat exchanger 14, reducing the system's cooling capacity and energy efficiency. Conversely, a low superheat will cause liquid carryover in the branches of heat exchanger 14. Therefore, the refrigeration system needs to operate at a suitable superheat. The superheat of the refrigeration system can be adjusted by regulating the opening of the regulating valve 13. The refrigeration control system 15 is connected to the regulating valve 13 and is used to control the opening of the regulating valve 13, thereby regulating the superheat of the refrigeration system.

[0096] Figure 2 The diagram shown is a flowchart of one embodiment of the refrigeration system control method of this application. The refrigeration system control method is used to control a refrigeration system. The refrigeration system control method includes steps 22, 23, and 24.

[0097] Step 22: Obtain the current gas supply of the refrigeration system.

[0098] The current gas delivery volume can be obtained in various ways. In some embodiments, when the compressor 11 of the refrigeration system consists of multiple compressors connected in parallel, it can be obtained by the number of compressors 11 that are started. Different numbers of compressors 11 being started result in different current gas delivery volumes. In other embodiments, when the compressor 11 is a screw compressor, it can be obtained by the position information of the slider. Different slider positions result in different current gas delivery volumes. The current gas delivery volume may change during the operation of the refrigeration system, and may vary at different times. In some embodiments, the compressor 11 includes multiple constant-speed positive displacement compressors. Step 22 includes: obtaining the sum of the gas delivery volumes of the multiple constant-speed positive displacement compressors. In other embodiments, the compressor 11 includes a variable-speed positive displacement compressor. Step 22 includes: obtaining the product of the displacement and speed of the variable-speed positive displacement compressor. In still other embodiments, the compressor 11 includes a screw compressor. Step 22 includes: obtaining the maximum gas delivery volume of the screw compressor; obtaining the position percentage of the slide valve of the screw compressor; obtaining the product of the position percentage of the slide valve and the maximum gas delivery volume.

[0099] Step 23: Determine the target superheat of the refrigeration system based on the current gas supply.

[0100] The target superheat of the refrigeration system is determined based on the current gas flow rate. In some embodiments, different current gas flow rates correspond to different target superheat rates. In other embodiments, some different current gas flow rates correspond to different target superheat rates, while some different current gas flow rates correspond to the same target superheat rate.

[0101] Step 24: Control the refrigeration system to operate at the target superheat level.

[0102] The refrigeration system is controlled to operate at the target superheat level determined in step 23, that is, the refrigeration system operates at the target superheat level corresponding to the current gas delivery volume, so that the heat exchange area of ​​the refrigeration system can adapt to the current gas delivery volume, and the heat exchanger 14 can obtain a suitable evaporation temperature.

[0103] In some embodiments, the target superheat of the refrigeration system is determined based on the current gas supply of the refrigeration system, and the refrigeration system is controlled to operate at the superheat corresponding to the current gas supply. This allows the superheat of the refrigeration system to change with the change in the current gas supply, so that the evaporation temperature of the refrigeration system can be adapted to the current gas supply, thereby increasing the cooling capacity, improving the energy efficiency of the refrigeration system, and saving energy.

[0104] In some embodiments, step 23 includes: obtaining the optimal superheat corresponding to the maximum gas delivery rate of the refrigeration system; and determining the target superheat of the refrigeration system based on the square of the ratio of the current gas delivery rate to the maximum gas delivery rate, the optimal superheat, and the minimum superheat.

[0105] In some embodiments, the optimal superheat of the refrigeration system can be obtained experimentally. In other embodiments, the optimal superheat of the refrigeration system is a set value stored in the refrigeration control system 15, and the optimal superheat is directly obtained when controlling the refrigeration system. In some embodiments, when the refrigeration system operates at the maximum gas delivery rate Y0, the corresponding superheat X0 is the optimal superheat. The minimum superheat of the refrigeration system is A. The target superheat of the refrigeration system X1 = A + (X0 - A) * (Y1 / Y0)^2. Wherein, the value of A ranges from 0 to 2℃. Substituting the current gas delivery rate into the above functional relationship, the superheat is obtained and used as the target superheat.

[0106] In some embodiments, step 23 includes: obtaining the optimal superheat corresponding to the maximum gas delivery rate of the refrigeration system; and determining the target superheat of the refrigeration system based on the ratio of the current gas delivery rate to the maximum gas delivery rate, the optimal superheat, and the minimum superheat.

[0107] In some embodiments, when the refrigeration system operates at its maximum gas delivery rate Y0, the corresponding superheat X0 is the optimal superheat. The minimum superheat of the refrigeration system is B. The target superheat of the refrigeration system is X1 = B + (X0 - B) * (Y1 / Y0). Here, the value of B ranges from 0 to 2℃. Substituting the current gas delivery rate into the above functional relationship yields the superheat, which is taken as the target superheat.

[0108] Figure 3 The diagram shown is a flowchart of another embodiment of the refrigeration system control method of this application. Figure 3As shown, before step 22, the refrigeration system control method includes step 21: when the refrigeration system is started, controlling the refrigeration system to operate at the optimal superheat for a first duration. Step 24 includes steps 241 and 242. Step 241: if the current gas delivery rate is not the maximum gas delivery rate, controlling the refrigeration system to operate at the optimal superheat for a second duration. Step 242: after the second duration, controlling the refrigeration system to operate at the target superheat.

[0109] When the refrigeration system is started, before obtaining the current gas delivery rate of the refrigeration system, it is first controlled to operate at the optimal superheat corresponding to the maximum gas delivery rate for a first duration. This ensures sufficient heat exchange area and evaporation temperature during system startup, improving the safety of the refrigeration system. In some embodiments, the first duration is 2 minutes. When it is obtained that the refrigeration system is operating at a partial gas delivery rate, to improve the safety of the refrigeration system, it is controlled to operate at the optimal superheat for a second duration. After the second duration, the refrigeration system is then controlled to operate at the target superheat corresponding to the partial gas delivery rate. In some embodiments, the second duration is 30 seconds. In some embodiments, step 24 includes: controlling the superheat of the refrigeration system to decrease from the optimal superheat to the target superheat in stages. When the refrigeration system is controlled to operate from the optimal superheat to the target superheat corresponding to the partial gas delivery rate, to improve system stability and avoid oscillation of the regulating valve 13, the superheat of the refrigeration system can be controlled to decrease from the optimal superheat to the target superheat corresponding to the partial gas delivery rate in stages. For example, if the optimal superheat is 12F and the target superheat is 8F, the superheat of the refrigeration system can be controlled to first decrease from 12F to 10F, and after a certain period of time, decrease to 8F.

[0110] In some embodiments, step 23 includes: obtaining the optimal superheat corresponding to the maximum gas delivery of the refrigeration system; obtaining the superheat offset value of the refrigeration system; and determining the difference between the optimal superheat and the superheat offset value as the target superheat.

[0111] The optimal superheat and superheat offset values ​​can be obtained experimentally or empirically and stored in the refrigeration control system 15 corresponding to the current gas delivery volume. If the current gas delivery volume is a partial gas delivery volume, the optimal superheat and superheat offset values ​​can be read to determine the target superheat corresponding to the partial gas delivery volume. In some embodiments, different current gas delivery volumes may have different superheat offset values, resulting in more precise control and improved energy efficiency. In other embodiments, some or all different current gas delivery volumes may have the same superheat offset value. Using the same superheat offset value simplifies and speeds up data processing. Furthermore, when the gas delivery volume changes little or rapidly, it is not necessary to frequently determine the target superheat or frequently adjust the superheat, thus improving the stability of system operation. In other embodiments, the superheat offset value has a functional relationship with the current gas delivery volume. Substituting the current gas delivery volume into the functional relationship yields the superheat offset value, which in turn yields the target superheat corresponding to the partial gas delivery volume. Different gas delivery volumes can yield different superheat offset values, resulting in a more accurate target superheat and more precise control of the refrigeration system. This leads to better energy efficiency and energy savings. Different refrigeration systems may have different superheat offset values.

[0112] In some embodiments, the target superheat includes multiple partial gas delivery target superheats corresponding to different partial gas delivery volumes. In some embodiments, the optimal superheat and partial gas delivery target superheat of the refrigeration system are set values, which can be set according to experiments or experience, and the corresponding gas delivery volume conditions are stored in the refrigeration control system 15. When the refrigeration system operates at maximum gas delivery volume, the optimal superheat is directly obtained as the target superheat of the refrigeration system. When the refrigeration system operates at partial gas delivery volume, the partial gas delivery target superheat is directly obtained as the target superheat of the refrigeration system. This is simple and quick, making control faster. In some other embodiments, the target superheat has a functional relationship with the gas delivery volume. Substituting the current gas delivery volume into the functional relationship yields the target superheat. Substituting the maximum gas delivery volume into the functional relationship yields the optimal superheat, and substituting the partial gas delivery volume into the functional relationship yields the partial gas delivery target superheat. Different partial gas delivery volumes can yield different partial gas delivery target superheats, thus obtaining a more accurate target superheat, more precise control of the refrigeration system, and thus better improving the energy efficiency of the refrigeration system and saving energy.

[0113] In some embodiments, the refrigeration system includes three compressors connected in parallel. When the refrigeration system operates at its maximum gas delivery rate, the optimal superheat is set to 12°F. When the refrigeration system operates at a partial gas delivery rate, the target superheat for the partial gas delivery rate is set to 9°F and 6°F. Specifically, when the refrigeration system operates at half gas delivery rate, the target superheat for the partial gas delivery rate is 9°F, and when the refrigeration system operates at less than half gas delivery rate, the target superheat for the partial gas delivery rate is 6°F.

[0114] In some embodiments, the refrigeration system includes two compressors connected in parallel. When the refrigeration system operates at maximum gas delivery, the optimal superheat is set to 12°F. When the refrigeration system operates at partial gas delivery, the partial gas delivery target superheat is set to 6°F.

[0115] In some embodiments, step 23 includes: if the current gas delivery volume is a partial gas delivery volume, determining the target superheat of the partial gas delivery volume corresponding to the current gas delivery volume based on the mapping relationship between multiple partial gas delivery volumes and multiple target superheat of partial gas delivery volumes.

[0116] Multiple partial gas delivery volumes are mapped to multiple target superheat values ​​for those partial gas delivery volumes. These mapping relationships are stored in the refrigeration control system 15. Substituting the current gas delivery volume into the mapping relationship yields the corresponding target superheat value for that partial gas delivery volume. In some embodiments, multiple partial gas delivery volumes correspond one-to-one with multiple different target superheat values ​​for those partial gas delivery volumes. In other embodiments, multiple partial gas delivery volumes may correspond to the same target superheat value for those partial gas delivery volumes. In some embodiments, the partial gas delivery volume includes multiple intervals, each interval including multiple numerically consecutive partial gas delivery volumes. Multiple target superheat values ​​for those partial gas delivery volumes correspond one-to-one with multiple intervals. Based on the interval in which the current gas delivery volume is located, substituting it into the mapping relationship between multiple intervals and multiple target superheat values ​​for those partial gas delivery volumes yields the target superheat value for the partial gas delivery volume corresponding to the current gas delivery volume.

[0117] In some embodiments, the target superheat of the refrigeration system can be obtained experimentally. For example... Figure 4 As shown, lines a, b, and c represent the actual superheat of the refrigeration system at 12°C, 10°C, and 8°C, respectively. During the operation of the refrigeration system, the superheat is gradually reduced. The target superheat is selected as the superheat at which regulating valve 13 can operate stably and with high energy efficiency. The optimal target superheat can be obtained by performing IPLV (Integrated Part Load Value) testing on the refrigeration system, or by performing partial load testing on the refrigeration system to obtain the optimal target superheat under different partial gas delivery rates.

[0118] In some embodiments, step 23 includes: determining a target superheat based on the functional relationship between gas supply and superheat, wherein the relationship between gas supply and superheat is a linear functional relationship.

[0119] The gas delivery rate and superheat have a linear functional relationship. Based on this relationship and the current gas delivery rate, the target superheat can be determined. Substituting the current gas delivery rate into the relationship between gas delivery rate and superheat yields the target superheat.

[0120] In some embodiments, compressor 11 is a screw compressor. Determining the target superheat based on the relationship between gas delivery volume and superheat includes: determining the superheat value corresponding to the gas delivery volume as the target superheat value based on the functional relationship between superheat value and gas delivery volume, the maximum gas delivery volume of the refrigeration system, and the minimum gas delivery volume of the refrigeration system. The superheat value is directly proportional to the difference between the gas delivery volume and the minimum gas delivery volume, directly proportional to the difference between the maximum and minimum superheat values ​​of the refrigeration system, and inversely proportional to the difference between the maximum and minimum gas delivery volumes.

[0121] The relationship between the superheat SH of the screw compressor and the gas delivery rate is: SH = (LOAD - MIN.LOAD) * (SH.100% - SH.MIN) / (LOAD.100% - MIN.LOAD). Where LOAD is the gas delivery rate, MIN.LOAD is the minimum gas delivery rate of the refrigeration system, SH.100% is the maximum superheat of the refrigeration system, SH.MIN is the minimum superheat of the refrigeration system, LOAD.100% is the maximum gas delivery rate of the refrigeration system, and MIN.LOAD is the minimum gas delivery rate of the refrigeration system. The gas delivery rate is determined by the displacement of the screw compressor's slider; the minimum gas delivery rate corresponds to the minimum displacement, and the maximum gas delivery rate corresponds to the maximum displacement. By obtaining the current gas delivery rate data and substituting it into the above function, the corresponding superheat can be obtained, which can be used as the target superheat.

[0122] In some embodiments, compressor 11 is a variable frequency compressor. Step 22 includes: acquiring current data of compressor speed. Determining the target superheat of the refrigeration system based on the relationship between gas delivery volume and superheat includes: determining the target superheat based on the functional relationship between superheat and compressor speed, and the maximum and minimum speeds of the compressor, wherein the superheat is directly proportional to the difference between the current compressor speed and the minimum speed, directly proportional to the difference between the maximum and minimum superheats of the refrigeration system, and inversely proportional to the difference between the maximum and minimum speeds.

[0123] The relationship between the superheat SH of the variable frequency compressor and the gas delivery rate is: SH = (RPS - RPS.MIN) * (SH.MAX - SH.MIN) / (RPS.MAX - RPS.MIN) + 6. Where RPS is the compressor speed, RPS.MIN is the minimum compressor speed, RPS.MAX is the maximum compressor speed, SH.MAX is the maximum superheat of the refrigeration system, and SH.MIN is the minimum superheat of the refrigeration system. Substituting the current compressor speed data into the above function, the superheat is obtained and used as the target superheat.

[0124] In some embodiments, determining the target superheat of the refrigeration system includes: obtaining the current gas delivery density of the compressor 11; and determining the target superheat of the refrigeration system based on the current gas delivery density and the maximum gas delivery density of the compressor 11. The target superheat is determined not only by the gas delivery volume of the refrigeration system but also by the current gas delivery density of the refrigeration system. In some embodiments, the compressor 11 includes a suction port. Obtaining the current gas delivery density of the compressor 11 includes: determining the pressure and temperature of the suction port; and determining the current gas delivery density of the compressor 11 based on the pressure and temperature of the suction port. In some embodiments, determining the pressure of the suction port includes: determining the pressure of the suction port based on the saturation pressure corresponding to the middle temperature of the evaporator 16.

[0125] In some embodiments, determining the target superheat of the refrigeration system based on the current gas delivery density and the maximum gas delivery density of the compressor 11 includes: obtaining the optimal superheat and maximum gas delivery density corresponding to the maximum gas delivery volume of the refrigeration system; and determining the target superheat of the refrigeration system based on the ratio of the maximum gas delivery density to the current gas delivery density and the optimal superheat. In some embodiments, the maximum gas delivery density of the refrigeration system can be obtained experimentally. In other embodiments, the maximum gas delivery density of the refrigeration system is a set value stored in the refrigeration control system 15, and the maximum gas delivery density is directly obtained when controlling the refrigeration system. The optimal superheat is X0, the maximum gas delivery density is D0, the current gas delivery density is D1, and the target superheat is X1 = X0 * (D0 / D1). Substituting the current gas delivery density into the above functional relationship yields the superheat, which is used as the target superheat.

[0126] In some embodiments, determining the target superheat of the refrigeration system based on the current gas delivery density and the maximum gas delivery density of the compressor 11 includes: determining the target superheat of the refrigeration system based on the square of the ratio of the current gas delivery volume to the maximum gas delivery volume, the ratio of the maximum gas delivery density to the current gas delivery density, the optimal superheat, and the minimum superheat. The optimal superheat is X0, the maximum gas delivery density is D0, the current gas delivery density is D1, the current gas delivery volume is Y1, the maximum gas delivery volume is Y0, the minimum superheat is A, and the target superheat value X1 = (A + (X0 - A) * (Y1 / Y0)^2) * (D1 / D0). Substituting the current gas delivery density into the above functional relationship yields the superheat, which is used as the target superheat.

[0127] In other embodiments, determining the target superheat of the refrigeration system based on the current gas delivery density and the maximum gas delivery density of compressor 11 includes: determining the target superheat of the refrigeration system based on the ratio of the current gas delivery volume to the maximum gas delivery volume, the ratio of the maximum gas delivery density to the current gas delivery density, the optimal superheat, and the minimum superheat. The optimal superheat is X0, the maximum gas delivery density is D0, the current gas delivery density is D1, the current gas delivery volume is Y1, the maximum gas delivery volume is Y0, the minimum superheat is B, and the target superheat value X1 = (B + (X0 - B) * (Y1 / Y0)) * (D1 / D0). Substituting the current gas delivery density into the above functional relationship yields the superheat, which is used as the target superheat.

[0128] In some embodiments, determining the target superheat of the refrigeration system includes: obtaining the current inlet flow rate of the evaporator 16 when the rate of change of the distribution effect-related parameters is within a set range; obtaining the optimal inlet flow rate of the evaporator 16 when the distribution effect-related parameters characterize the optimal pipe flow distribution effect of the evaporator 16; and determining the target superheat of the refrigeration system based on the current inlet flow rate and the optimal inlet flow rate. The distribution effect-related parameters characterize the pipe flow distribution effect of the evaporator 16.

[0129] If the rate of change of the parameters related to the distribution effect is within the set range, it indicates that the flow distribution effect of the evaporator 16 is not significantly affected or remains unchanged. The flow distribution effect of the evaporator 16 can be considered as the uniformity of refrigerant distribution within the evaporator 16 pipes. When the flow distribution effect of the evaporator 16 is optimal, the target superheat is determined based on the inlet velocity of the evaporator 16.

[0130] In some embodiments, determining the target superheat of the refrigeration system based on the current flow rate and the optimal flow rate includes: obtaining the maximum inlet flow rate of the evaporator 16 corresponding to the maximum gas delivery rate of the refrigeration system; and determining the target superheat of the refrigeration system based on the difference between the maximum inlet flow rate and the optimal inlet flow rate, and the difference between the current inlet flow rate and the optimal inlet flow rate. The optimal superheat is X0, the maximum inlet flow rate is V0, the optimal inlet flow rate is V, the current inlet flow rate is V1, and the target superheat X1 = X0 * [(V0-V) / (V1-V)] * C, where C is a correction coefficient; in some embodiments, C = 1 / 2. Substituting the current inlet flow rate into the above functional relationship yields the superheat, which is used as the target superheat.

[0131] In some embodiments, obtaining the current inlet flow rate of the evaporator 16 includes obtaining the current inlet flow rate of the evaporator 16 based on the flow rate of the compressor 11, the suction density, the suction pressure, and the inlet temperature of the regulating valve 13.

[0132] In other embodiments, obtaining the current flow rate of the evaporator 16 includes obtaining the current inlet flow rate of the evaporator 16 based on the flow rate of the compressor 11, the suction density, the suction pressure, the inlet temperature of the regulating valve 13, the outlet temperature, the inlet flow rate, and the outlet flow rate.

[0133] In some embodiments, determining the target superheat of the refrigeration system includes: obtaining the current gas delivery density of the compressor 11; obtaining the current inlet flow rate of the evaporator 16 when the rate of change of the distribution effect-related parameters is within a set range; obtaining the optimal inlet flow rate of the evaporator 16 when the distribution effect-related parameters characterize the optimal pipe flow distribution effect of the evaporator 16; and determining the target superheat of the refrigeration system based on the current gas delivery density, the maximum gas delivery density of the compressor, the current inlet flow rate, and the optimal inlet flow rate. By simultaneously considering the gas delivery volume, gas delivery density, and inlet flow rate of the evaporator 16 when determining the target superheat, the target superheat is more accurate, which can better improve the energy efficiency of the refrigeration system.

[0134] like Figure 5 As shown, this application provides a refrigeration control system 15, including one or more processors 31, for implementing the refrigeration system control method described above. The above embodiments can be implemented through software, hardware, or a combination of both.

[0135] In some embodiments, the cooling control system 15 may include a computer-readable storage medium 32, which may store a program that can be invoked by a processor 31, and may include a non-volatile storage medium. In some embodiments, the cooling control system 15 may include memory 33 and an interface 34. In some embodiments, the cooling control system 15 may also include other hardware depending on the specific application.

[0136] This application also provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the cooling system control method described above. The computer-readable medium includes permanent and non-permanent, removable and non-removable media, and information storage can be implemented by any method or technology. The information can be computer-readable instructions, data structures, program modules, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic magnetic disk storage or other magnetic storage devices, or any other non-transfer medium that can be used to store information accessible by a computing device.

[0137] The following experiments further illustrate this application. Table 1 shows the test data for the CGAM refrigeration system using an R410A compressor. Table 2 shows the test data for the CGAM refrigeration system using an R454B compressor. Table 3 shows the test data for the CGAM refrigeration system using a VVI compressor, with a target superheat of 12°F at partial gas delivery. The refrigeration system includes two compressors, compressor A and compressor B. Tests were conducted on the refrigeration system at 100% gas delivery, 75% gas delivery, compressor B at 75% gas delivery, compressor A at 50% gas delivery, and compressor A at 25% gas delivery. The test results yielded the refrigeration system's OAT (outdoor temperature), TON (tonnage of cooling capacity), COP (coefficient of performance), Subcooling, FanP (fan power consumption), SST (evaporation temperature), and IPLV (integrated partial gas delivery performance coefficient).

[0138]

[0139] Table 1

[0140] Table 2

[0141]

[0142]

[0143] Table 3

[0144] Comparing Tables 1, 2, and 3, it can be seen that the VVI compressor, when operating at partial gas delivery, has a significantly higher IPLV (Integrated Partial Gas Delivery Performance) than the R410A and R454B compressors. This indicates that using a VVI compressor in a refrigeration system can improve the system's energy efficiency at partial gas delivery.

[0145] Table 4 shows the test data for the CGAM refrigeration system using a VVI compressor. At partial gas flow, the target superheat is 8°F. Comparing Tables 3 and 4, at partial gas flow, the target superheat decreases from 12°F to 8°F, while the IPLV increases from 4.49 to 4.70, indicating improved partial gas flow efficiency of the refrigeration system. Furthermore, at partial gas flow, the evaporation temperature (SST) significantly increases, demonstrating that reducing the target superheat at partial gas flow helps increase the evaporation temperature, thereby improving the energy efficiency of the refrigeration system.

[0146]

[0147] Table 4

[0148] Table 5 shows the test data for the CGAM070 refrigeration system, with a target superheat of 10.8°F. Table 6 shows the test data for the CGAM070 refrigeration system, with a target superheat of 7.2°F at a partial gas flow rate. Comparing Tables 5 and 6, it can be seen that the IPLV in Table 6 is significantly improved. This indicates that reducing the target superheat at a partial gas flow rate can improve the IPLV.

[0149]

[0150] Table 5

[0151] Table 6

[0152] Figure 6 The figures show test data for a refrigeration system using the refrigeration system control method of this application. Refrigeration system 1 initially operates at a partial gas flow rate with a target superheat of 9.4°F. After 5 minutes, it operates at the maximum gas flow rate with a target superheat of 12°F. After 1 hour, it operates again at a partial gas flow rate with a superheat of 9.4°F. Refrigeration system 2 continuously operates at a partial gas flow rate with a target superheat of 9.4°F. Figure 6 In the diagram, line a represents the suction pressure of refrigeration system 2, line b represents the suction pressure of refrigeration system 1, line c represents the inlet water temperature of the refrigeration system, line d represents the outlet water temperature of the refrigeration system, line e represents the working pressure of the regulating valve of refrigeration system 1, line f represents the working pressure of the regulating valve of refrigeration system 2, line g represents the superheat of refrigeration system 1, and line h represents the superheat of refrigeration system 2.

[0153] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the application disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this application are indicated by the following claims.

[0154] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A method for controlling a refrigeration system, characterized in that, A method for controlling a refrigeration system includes: Obtain the optimal superheat corresponding to the maximum gas delivery rate of the refrigeration system; When the refrigeration system is started, the refrigeration system is controlled to operate at the optimal superheat for a first duration; Obtain the current gas delivery rate of the refrigeration system; The target superheat of the refrigeration system is determined based on the current gas supply rate; wherein the target superheat of the refrigeration system is determined based on the ratio of the current gas supply rate to the maximum gas supply rate, the optimal superheat, and the minimum superheat. The refrigeration system is controlled to operate at the target superheat.

2. The refrigeration system control method according to claim 1, characterized in that, Determining the target superheat of the refrigeration system based on the current gas supply includes: The target superheat of the refrigeration system is determined based on the square of the ratio of the current gas supply to the maximum gas supply, the optimal superheat, and the minimum superheat.

3. The refrigeration system control method according to claim 1, characterized in that, Controlling the refrigeration system to operate at the target superheat includes: If the current gas delivery rate is not the maximum gas delivery rate, the refrigeration system is controlled to operate for a second duration at the optimal superheat. After a second period of time, the refrigeration system is controlled to operate at the target superheat.

4. The refrigeration system control method according to claim 3, characterized in that, Controlling the refrigeration system to operate at the target superheat includes: The superheat of the refrigeration system is controlled to decrease from the optimal superheat in stages to the target superheat.

5. The refrigeration system control method according to claim 1, characterized in that, The target superheat includes multiple different partial gas delivery volume target superheat corresponding to partial gas delivery volume; Determining the target superheat of the refrigeration system based on the current gas supply includes: If the current gas delivery volume is a partial gas delivery volume, the target superheat of the partial gas delivery volume corresponding to the current gas delivery volume is determined according to the mapping relationship between multiple partial gas delivery volumes and the target superheat of the multiple partial gas delivery volumes.

6. A method for controlling a refrigeration system, characterized in that, A method for controlling a refrigeration system, the refrigeration system control method comprising: Obtain the optimal superheat corresponding to the maximum gas delivery rate of the refrigeration system; When the refrigeration system is started, the refrigeration system is controlled to operate at the optimal superheat for a first duration; Obtain the current gas delivery rate of the refrigeration system; Based on the functional relationship between the superheat and the gas supply volume, the maximum gas supply volume of the refrigeration system, the minimum gas supply volume of the refrigeration system, the maximum superheat of the refrigeration system, and the minimum superheat of the refrigeration system, the value of the superheat corresponding to the current gas supply volume is determined as the target superheat. The superheat is directly proportional to the difference between the gas supply volume and the minimum gas supply volume, directly proportional to the difference between the maximum superheat of the refrigeration system and the minimum superheat of the refrigeration system, and inversely proportional to the difference between the maximum gas supply volume and the minimum gas supply volume. The refrigeration system is controlled to operate at the target superheat.

7. The refrigeration system control method according to claim 6, characterized in that, The refrigeration system includes a compressor, which is a screw compressor.

8. A method for controlling a refrigeration system, characterized in that, A method for controlling a refrigeration system, the refrigeration system including a compressor, includes: Obtain the optimal superheat corresponding to the maximum gas delivery rate of the refrigeration system; When the refrigeration system is started, the refrigeration system is controlled to operate at the optimal superheat for a first duration; Obtain the current data of the compressor speed; The target superheat is determined based on the functional relationship between superheat and compressor speed, the maximum and minimum speeds of the compressor, and the maximum and minimum superheat of the refrigeration system. The target superheat is directly proportional to the difference between the current compressor speed and the minimum speed, directly proportional to the difference between the maximum and minimum superheat of the refrigeration system, and inversely proportional to the difference between the maximum and minimum speeds.

9. The refrigeration system control method according to claim 8, characterized in that, The compressor is a variable frequency compressor.

10. The refrigeration system control method according to claim 1, characterized in that, The refrigeration system includes a compressor, and the compressor includes multiple constant-speed positive displacement compressors; The step of obtaining the current gas supply of the refrigeration system includes: Obtain the sum of the gas delivery volumes of the plurality of constant-speed positive displacement compressors.

11. The refrigeration system control method according to claim 1, characterized in that, The refrigeration system includes a compressor, and the compressor includes a variable speed positive displacement compressor; obtaining the current gas delivery rate of the refrigeration system includes: Obtain the product of the displacement and the rotational speed of the variable speed positive displacement compressor.

12. The refrigeration system control method according to claim 1, characterized in that, The refrigeration system includes a compressor, which includes a screw compressor; obtaining the current gas delivery rate of the refrigeration system includes: Obtain the maximum gas delivery capacity of the screw compressor; Obtain the position percentage of the slide valve of the screw compressor; Obtain the product of the position percentage of the slide valve and the maximum gas delivery volume.

13. A computer-readable storage medium, characterized in that, It stores a computer program that, when executed by a processor, implements the refrigeration system control method as described in any one of claims 1 to 12.

14. A refrigeration control system, characterized in that, It includes one or more processors for performing the refrigeration system control method as described in any one of claims 1 to 12.

15. A refrigeration system, characterized in that, Includes the refrigeration control system as described in claim 14.

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