REFRIGERATING SYSTEM, METHOD FOR CONTROLLING REFRIGERATING SYSTEM, AND STORAGE MEDIUM

Description

FOREIGN PRIORITY

This application claims benefit of Chinese Patent Application No. 202410330166.3, filed Mar. 21, 2024, and all the benefits accruing therefrom under 35 U.S.C. § 119, the contents of which in its entirety are herein incorporated by reference.

BACKGROUND

This application relates to the field of refrigerating systems, and specifically to a refrigerating system, a method for controlling a refrigerating system, and a computer-readable storage medium.

SUMMARY OF THE INVENTION

Described herein is a refrigerating system, a method for controlling a refrigerating system, and a computer-readable storage medium, so as to at least solve or alleviate some of the problems of existing refrigerating systems.

A first aspect of this application provides a refrigerating system, including a compressor, a condenser, an economizer, an evaporator, a first throttling device and a second throttling device. The compressor has a discharge port, a first suction port, and a second suction port. An inlet of the condenser is in communication with the discharge port of the compressor. An outlet of the evaporator is in communication with the first suction port of the compressor. An inlet of the economizer is in communication with an outlet of the condenser, a gas outlet of the economizer is in communication with the second suction port of the compressor, and a liquid outlet of the economizer is in communication with an inlet of the evaporator. The first throttling device is provided on a pipe connecting the condenser and the economizer. The second throttling device is provided on a pipe connecting the economizer and the evaporator.

The refrigerating system further includes a first throttling device control mode setting module and a first throttling device control module. The first throttling device control mode setting module receives at least one parameter associated with operation of the compressor, determines whether the at least one parameter indicates that the compressor is under a preset surge protection condition, and selects between a normal control mode and a surge protection control mode based on the determination. The first throttling device control module controls the first throttling device in the normal control mode in response to the first throttling device control mode setting module selecting the normal control mode, and controls the first throttling device in the surge protection control mode in response to the first throttling device control mode setting module selecting the surge protection control mode.

In one or more embodiments of the refrigerating system, the condenser is provided with a first liquid level sensor configured to detect a current liquid level of the condenser. In the normal control mode, the first throttling device control module receives current liquid level information of the condenser sent by the first liquid level sensor, and controls an open degree of the first throttling device based on a comparison result between the current liquid level of the condenser and a target liquid level of the condenser.

In one or more embodiments of the refrigerating system, in the surge protection control mode, the first throttling device control module controls an open degree of the first throttling device to increase a refrigerant gas suction amount of the second suction port.

In one or more embodiments the refrigerating system, when switching from the normal control mode to the surge protection control mode, the first throttling device control module controls the open degree of the first throttling device to increase.

In one or more embodiments of the refrigerating system, the at least one parameter includes a lift of the refrigerating system.

In one or more embodiments of the refrigerating system, the first throttling device control mode setting module selects the surge protection control mode when the lift of the refrigerating system is greater than a threshold.

In one or more embodiments of the refrigerating system, the economizer is provided with a second liquid level sensor configured to detect a current liquid level of the economizer. The refrigerating system further includes a second throttling device control module that receives current liquid level information of the economizer sent by the second liquid level sensor, and controls an open degree of the second throttling device based on a comparison result between the current liquid level information of the economizer and a target liquid level of the economizer.

In one or more embodiments of the refrigerating system, the first throttling device and/or the second throttling device is an electric butterfly valve.

A second aspect of this application provides a method for controlling a refrigerating system. The refrigerating system includes a compressor, a condenser, an economizer, an evaporator, a first throttling device and a second throttling device. The compressor has a discharge port, a first suction port, and a second suction port. An inlet of the condenser is in communication with the discharge port of the compressor. An outlet of the evaporator is in communication with the first suction port of the compressor. An inlet of the economizer is in communication with an outlet of the condenser, a gas outlet of the economizer is in communication with the second suction port of the compressor, and a liquid outlet of the economizer is in communication with an inlet of the evaporator. The first throttling device is provided on a pipe connecting the condenser and the economizer. The second throttling device is provided on a pipe connecting the economizer and the evaporator. The method includes: a step of receiving at least one parameter associated with operation of the compressor; a step of determining whether the at least one parameter indicates that the compressor is under a preset surge protection condition; a step of selecting between a normal control mode and a surge protection control mode based on the determination; a step of controlling the first throttling device in the normal control mode in response to selecting the normal control mode; and a step of controlling the first throttling device in the surge protection control mode in response to selecting the surge protection control mode.

In the method for controlling a refrigerating system, in the step of “controlling the first throttling device in the normal control mode”, an open degree of the first throttling device is controlled based on a comparison result between the current liquid level information of the condenser and a target liquid level of the condenser. In the step of “controlling the first throttling device in the surge protection control mode”, the open degree of the first throttling device is controlled to increase a refrigerant gas suction amount of the second suction port.

In the method for controlling a refrigerating system, in the step of “controlling the first throttling device in the surge protection control mode”, when switching from the normal control mode to the surge protection control mode, the open degree of the first throttling device is controlled to increase.

The method for controlling a refrigerating system, further includes a step of controlling an open degree of the second throttling device based on a comparison result between the current liquid level information of the economizer and a target liquid level of the economizer.

A third aspect of this application provides a computer-readable storage medium storing a processor-readable instruction, in which the processor-readable instruction is executed by a processor to perform the method for controlling a refrigerating system according to any one of the above embodiments.

DESCRIPTIONS OF THE DRAWINGS

FIG. 1 shows a schematic diagram of a refrigerating system according to one or more embodiments of this application;

FIG. 2 shows a schematic diagram of a refrigerating system according to one or more embodiments of this application;

FIG. 3 shows a flowchart of a method for controlling a refrigerating system according to one or more embodiments of this application;

FIG. 4 shows a schematic diagram of control areas of a first throttling device corresponding to a normal control mode and a surge protection control mode respectively according to one or more embodiments of this application.

LIST OF REFERENCE NUMERALS

• • 100 refrigerating system; 1 compressor; 12 discharge port; 13 second suction port; 14 first suction port; 2 condenser; 21 first liquid level sensor; 22 inlet of condenser; 23 outlet of condenser; 3 economizer; 31 second liquid level sensor; 32 inlet of economizer; 33 gas outlet of economizer; 34 liquid outlet of economizer; 4 evaporator; 41 inlet of evaporator; 42 outlet of evaporator; 5 first throttling device; 6 second throttling device; 7 control device; 71 first throttling device control mode setting module; 72 first throttling device control module; 73 second throttling device control module.

DETAILED DESCRIPTION

First, it should be noted that compositions, working principles, characteristics, advantages, and the like of a refrigerating system, a method for controlling a refrigerating system and a computer-readable storage medium according to this application will be described below in an illustrative manner. However, it should be understood that all descriptions are given for illustrative purposes only and should not be construed as any limitation to this application.

In addition, for any single technical feature described or implicit in the embodiments mentioned herein, or any single technical feature illustrated or implicit in the drawings, this application still allows any combination or deletion between these technical features (or their equivalents) without any technical obstacles, thereby obtaining other embodiments of this application that may not be directly mentioned herein.

In refrigerating systems, there is a need to control liquid levels in a condenser and an economizer, and prevent a compressor from surging. Existing systems have a problem of poor control accuracy or high manufacturing cost due to complex structures. According to the refrigerating system, the method for controlling a refrigerating system and the computer-readable storage medium of this application, a demand for surge protection of a compressor is met with a solution that is relatively simple in structure and low in cost.

FIG. 1 shows a refrigerating system 100 according to one or more embodiments of this application. The refrigerating system 100 includes a compressor 1, a condenser 2, an economizer 3 and an evaporator 4 connected by a refrigerant circulation pipe. The compressor 1 has a discharge port 12, a second suction port 13 and a first suction port 14. An inlet 22 of the condenser 2 is in communication with the discharge port 12 of the compressor 1. An inlet 32 of the economizer 3 is in communication with an outlet 23 of the condenser 2, and a gas outlet 33 of the economizer 3 is in communication with the second suction port 13 of the compressor 1. An inlet 41 of the evaporator 4 is in communication with a liquid outlet 34 of the economizer 3, and an outlet 42 of the evaporator 4 is in communication with the first suction port 14 of the compressor 1. A first throttling device 5 is provided on a pipe connecting the condenser 2 and the economizer 3. A second throttling device 6 is provided on a pipe connecting the economizer 3 and the evaporator 4.

Types and specifications of the compressor 1, the condenser 2, the economizer 3 and the evaporator 4 may be appropriately selected from the types and specifications known in the art. As a specific example, the compressor 1 is a centrifugal compressor. The condenser 2 and the evaporator 4 are both shell-and-tube heat exchangers, with the refrigerant passing through the shell side and a working fluid passing through the tube side. The economizer 3 is a flash evaporator.

Referring to FIG. 1 and FIG. 2, the refrigerating system 100 further includes a first throttling device control mode setting module 71 and a first throttling device control module 72.

The first throttling device control mode setting module 71 receives at least one parameter associated with operation of the compressor 1, determines whether the at least one parameter indicates that the compressor 1 is under a preset surge protection condition, and selects between a normal control mode and a surge protection control mode based on the determination. The first throttling device control module 72 controls an open degree of the first throttling device 5 in the normal control mode in response to the first throttling device control mode setting module 71 selecting the normal control mode, and controls the open degree of the first throttling device 5 in the surge protection control mode in response to the first throttling device control mode setting module 71 selecting the surge protection control mode.

In one or more embodiments, referring to FIG. 4, the at least one parameter includes a lift of the refrigerating system 100. Corresponding to a respective system loading rate, when the lift of the refrigerating system 100 is greater than a threshold (the gray area in FIG. 4), it means that at this lift, the compressor 1 will be affected by surge or the compressor 1 has been affected by surge. At this time, the first throttling device control mode setting module 71 selects the surge protection control mode, and the first throttling device control module 72 controls the first throttling device 5 in the surge protection control mode in response to the selection of the first throttling device control mode setting module 71, specifically adjusting and increasing an open degree of the first throttling device 5 so as to appropriately increase the amount of refrigerant entering the economizer 3. When other working conditions of the condenser 2 (such as entering water temperature and entering water amount or entering air temperature and entering air amount) remain unchanged, more refrigerant will flow into the economizer 3 and then can enter the second suction port 13 of the compressor in a state of refrigerant gas after being vaporized in the economizer 3, thereby increasing an air intake flow of the compressor 1 to avoid surge. Similarly, corresponding to a respective system loading rate, when the lift of the refrigerating system 100 is less than a threshold (the black area in FIG. 4), it means that at this lift, the compressor 1 is not easily affected by surge. At this time, the first throttling device control mode setting module 71 selects the normal control mode, and the first throttling device control module 72 controls the first throttling device 5 in the normal control mode in response to the selection of the first throttling device control mode setting module 71.

It should be noted that the “threshold” mentioned above is based on the system loading at the moment of obtaining the “lift of the refrigerating system 100”. In some embodiments, the “threshold” under different system loadings may be different.

In some embodiments, the at least one parameter received by the first throttling device control mode setting module 71 may further includes a detection result of a surge detector provided in the compressor 1. When the detection result is greater than a threshold, it indicates that the compressor 1 is under the preset surge protection condition, so the first throttling device control mode setting module 71 selects the surge protection control mode.

In some embodiments, the at least one parameter received by the first throttling device control mode setting module 71 may further includes a working point of the compressor 1. When the working point of the compressor 1 is close to a surge area of the compressor 1, it indicates that the compressor 1 is under the preset surge protection condition, so the first throttling device control mode setting module 71 selects the surge protection control mode.

In some embodiments, the first throttling device control mode setting module 71 has two outputs, namely, an output for selecting the normal control mode and an output for selecting the surge protection mode.

In some embodiments, the first throttling device control mode setting module 71 has three outputs, namely, an output for selecting the surge protection mode, an output for selecting the normal control mode and an output for selecting a balance control mode. That is, the first throttling device control mode setting module 71 can generate a variety of different outputs through multiple decision logics, and send the outputs to the first throttling device control module 72.

In some embodiments, the condenser 2 is provided with a first liquid level sensor 21 configured to detect a current liquid level of the condenser 2 and send current liquid level information of the condenser 2 to the first throttling device control module 72. In the normal control mode, the first throttling device control module 72 controls the open degree of the first throttling device 5 based on a comparison result between the current liquid level information of the condenser 2 and a target liquid level of the condenser 2.

By controlling the open degree of the first throttling device 5 provided downstream of the condenser 2, the liquid level of the condenser 2 can be controlled to be closer to the position or area of the target liquid level. In this way, the liquid level of the condenser 2 can be optimized, so that a load of the condenser 2 can be quickly adjusted to better respond to changes in working conditions and properties of the refrigerating system 100 can be balanced. In addition, by receiving the current liquid level information of the condenser 2, when the first throttling device 5 fails, the failure of the first throttling device 5 can be identified by discovering an abnormality of the current liquid level information of the condenser 2.

The first liquid level sensor 21 may be selected from a variety of types of sensors such as a float-type liquid level sensor, a pressure-type liquid level sensor, and a capacitance-type liquid level sensor. In some embodiments, selecting a capacitance-type liquid level sensor as the first liquid level sensor 21 is beneficial for rapid and reliable liquid level detection for refrigerants with different characteristics.

A method for comparing the current liquid level information of the condenser 2 and the target liquid level of the condenser 2, as well as a method for controlling the first throttling device 5, can be set according to needs.

For example, when the current liquid level information of the condenser 2 indicates that the current liquid level of the condenser 2 is lower than the target liquid level of the condenser 2, the open degree of the first throttling device 5 is reduced. When the current liquid level information of the condenser 2 indicates that the current liquid level of the condenser 2 is higher than the target liquid level of the condenser 2, the open degree of the first throttling device 5 is increased.

For another example, when the current liquid level information of the condenser 2 indicates that the current liquid level of the condenser 2 is lower than the target liquid level of the condenser 2, and a difference between the current liquid level of the condenser 2 and the target liquid level of the condenser 2 is greater than a threshold, the open degree of the first throttling device 5 is reduced. When the current liquid level information of the condenser 2 indicates that the current liquid level of the condenser 2 is higher than the target liquid level of the condenser 2, and the difference between the current liquid level of the condenser 2 and the target liquid level of the condenser 2 is greater than a threshold, the open degree of the first throttling device 5 is increased.

Although in some embodiments, in the normal control mode, the first throttling device control module 72 adjusts the first throttling device 5 based on the purpose of controlling the liquid level height of the condenser 2, this application is not limited thereto. For example, in some embodiments, in the normal control mode, the first throttling device control module 72 adjusts the first throttling device 5 based on a purpose of controlling a saturation temperature of the evaporator 4. In some embodiments, in the normal control mode, the first throttling device control module 72 adjusts the first throttling device 5 based on a purpose of balancing liquid levels of the condenser 2 and the economizer 3.

In some embodiments, in the surge protection control mode, the first throttling device control module 72 controls the open degree of the first throttling device 1 to increase a refrigerant gas suction amount of the second suction port 13.

In some embodiments, when switching from the normal control mode to the surge protection control mode, the first throttling device control module 72 controls and increases the open degree of the first throttling device 5. In this way, the refrigerant gas suction amount of the second suction port 13 can be increased to protect the compressor 1 from further surge.

It should be noted that, in order to increase the refrigerant gas suction amount of the second suction port 13 of the compressor 1, the first throttling device 5 is generally controlled by increasing the open degree of the first throttling device 5. Of course, depending on the original state of the first throttling device 5, the first throttling device 5 can be adjusted by maintaining the open degree of the first throttling device 5 while, for example, reducing the load of the compressor 1, or by making the open degree of the first throttling device 5 larger than the normal open degree required, or the first throttling device 5 and the second throttling device 6 can be adjusted in conjunction. In other words, the first throttling device 5 is controlled based on the purpose of increasing the refrigerant gas suction amount of the second suction port 13 of the compressor 1, and the specific control method can be carried out according to actual conditions.

By the surge protection control mode, the first throttling device 5 can be used to easily implement surge protection for the compressor 1, and there is no need to separately provide pipeline equipment such as a hot gas bypass valve. The structure of the refrigerating system 100 will be simplified, thereby reducing failure rate and production cost of the refrigerating system 100.

In some embodiments, in the surge protection control mode, the first throttling device 5 is maintained at a fixed and large open degree to simplify a control logic of a surge protection control mode.

In some embodiments, in the surge protection control mode, the first throttling device 5 is maintained within a large open degree range to take into account other control purposes such as controlling the liquid level of the condenser 2.

In some embodiments, the economizer 3 is provided with a second liquid level sensor 31 configured to detect a current liquid level of the economizer 3. The refrigerating system 100 further includes a second throttling device control module 73 that receives current liquid level information of the economizer 3 sent by the second liquid level sensor 31, and controls an open degree of the second throttling device 6 based on a comparison result between the current liquid level information of the economizer 3 and a target liquid level of the economizer 3.

By controlling the open degree of the second throttling device 6 provided downstream of the economizer 3, the liquid level of the economizer 3 can be controlled to be closer to the position or area of the target liquid level. In this way, the liquid level of the economizer 3 can be optimized, so that properties of the refrigerating system 100 can be better balanced. In addition, by receiving the current liquid level information of the economizer 3, when the second throttling device 6 fails, the failure of the second throttling device 6 can be identified by discovering an abnormality of the current liquid level information of the economizer 3.

The second liquid level sensor 31 may be selected from a variety of types of sensors such as a float-type liquid level sensor, a pressure-type liquid level sensor, and a capacitance-type liquid level sensor. In some embodiments, as the second liquid level sensor 31, a liquid level sensor of the same type as the first liquid level sensor 21 is selected.

A method for comparing the current liquid level information of the economizer 3 and the target liquid level of the economizer 3, as well as a method for controlling the second throttling device 6, can be set by referring to the method for comparing the current liquid level information of the condenser 2 and the target liquid level of the condenser 2, as well as the method for controlling the first throttling device 5 described above, and will not be repeated here.

In some embodiments, the second throttling device control module 73 controls the second throttling device 6 in a single control mode.

In some embodiments, the second throttling device control module 73 controls the second throttling device 6 by switching between a plurality of control modes.

In some embodiments, referring to FIG. 1 and FIG. 2, the refrigerating system 100 includes a control device 7, the control device 7 includes a first throttling device control mode setting module 71, a first throttling device control module 72 and a second throttling device control module 73. The first throttling device 5, the second throttling device 6, the first liquid level sensor 21 and the second liquid level sensor 31 are all communicatively coupled to the control device 7. Of course, FIG. 1 and FIG. 2 are merely examples. As long as a first throttling device control mode setting module 71, a first throttling device control module 72 and a second throttling device control module 73 can implement corresponding information receiving and information processing, they are all within the technical scope of this application.

In some embodiments, the first throttling device 5 and the second throttling device 6 are both electric butterfly valves. The electric butterfly valve has the characteristics of fast response and can provide accurate flow control. By using the electric butterfly valve, it is beneficial for the first throttling device 5 and the second throttling device 6 to respond more timely to the real-time liquid level conditions inside the condenser 2 and the economizer 3 respectively. That is, the electric butterfly valve is particularly suitable for usage scenarios where the purpose is to control flow. In some embodiments where flow control is not required, an expansion valve or other types of combined components that can be used for throttling may also be selected as the first throttling device 5 and/or the second throttling device 6.

The method for controlling a refrigerating system 100 according to some embodiments of this application, referring to FIG. 3, includes: a step of receiving at least one parameter associated with operation of the compressor 1; a step of determining whether the at least one parameter indicates that the compressor 1 is under a preset surge protection condition; a step of selecting between a normal control mode and a surge protection control mode based on the determination; a step of controlling the first throttling device 5 in the normal control mode in response to selecting the normal control mode; and a step of controlling the first throttling device 5 in the surge protection control mode in response to selecting the surge protection control mode.

In some embodiments, in the step of “controlling the first throttling device 5 in the normal control mode”, an open degree of the first throttling device 5 is controlled based on a comparison result between the current liquid level information of the condenser 2 and a target liquid level of the condenser 2. In the step of “controlling the first throttling device 5 in the surge protection control mode”, the open degree of the first throttling device 5 is controlled to increase a refrigerant gas suction amount of the second suction port 13.

In some embodiments, in the step of “controlling the first throttling device 5 in the surge protection control mode”, when switching from the normal control mode to the surge protection control mode, the open degree of the first throttling device 5 is controlled to increase. At this time, even in the normal control mode, based on the current liquid level information of the condenser 2, the open degree of the first throttling device 5 is instructed to be reduced, but if the surge protection control mode is met at the same time, the instruction of the surge protection control mode will be given priority, that is, the open degree of the first throttling device 5 will be increased.

In some embodiments, the method further includes a step of controlling an open degree of the second throttling device 6 based on a comparison result between the current liquid level information of the economizer 3 and a target liquid level of the economizer 3.

The computer-readable storage medium according to some embodiments of this application stores a processor-readable instruction, and the processor-readable instruction is executed by a processor to perform the method for controlling a refrigerating system described in the one or more embodiments.

The above embodiments are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of this application shall be included in the protection scope of this application.