CN112611121B - Refrigerating system and control method of two-stage throttle valve - Google Patents
Refrigerating system and control method of two-stage throttle valve Download PDFInfo
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- CN112611121B CN112611121B CN202011540366.XA CN202011540366A CN112611121B CN 112611121 B CN112611121 B CN 112611121B CN 202011540366 A CN202011540366 A CN 202011540366A CN 112611121 B CN112611121 B CN 112611121B
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B1/00—Compression machines, plants or systems with non-reversible cycle
- F25B1/005—Compression machines, plants or systems with non-reversible cycle of the single unit type
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B43/00—Arrangements for separating or purifying gases or liquids; Arrangements for vaporising the residuum of liquid refrigerant, e.g. by heat
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2600/00—Control issues
- F25B2600/25—Control of valves
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B30/00—Energy efficient heating, ventilation or air conditioning [HVAC]
- Y02B30/70—Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating
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- Physics & Mathematics (AREA)
- Mechanical Engineering (AREA)
- Thermal Sciences (AREA)
- General Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Power Engineering (AREA)
- Control Of Non-Electrical Variables (AREA)
- Air Conditioning Control Device (AREA)
Abstract
The application discloses a refrigerating system and a control method of a two-stage throttle valve, wherein the refrigerating system comprises a compressor and an economizer, wherein the economizer is used for separating gaseous and liquid refrigerants, the gaseous refrigerants enter the compressor along a gas supplementing pipeline, and the liquid refrigerants enter an evaporator; the first-stage throttling valve is arranged between the condenser and the economizer and used for throttling the refrigerant; the second-stage throttle valve is arranged between the economizer and the evaporator and used for throttling the refrigerant; a controller configured to: acquiring the liquid level height of the economizer and the liquid level height of the evaporator; and controlling the opening of the primary throttle valve and the opening of the secondary throttle valve based on the liquid level height of the economizer, the liquid level height of the evaporator and the target liquid level height of the evaporator, thereby realizing the coordinated control of the two-stage throttle valve and effectively reducing the risks of liquid suction and liquid supplement.
Description
Technical Field
The application relates to the field of refrigeration system control, in particular to a refrigeration system and a control method of a two-stage throttle valve.
Background
The refrigeration system is a device that uses a refrigeration cycle of a refrigerant to cool or heat a room, and the refrigerant sequentially compresses, condenses, expands, and evaporates, thereby utilizing the characteristic that the refrigerant absorbs ambient heat when vaporizing and emits the heat when liquefying to perform a refrigeration or heating function.
In a refrigeration cycle system of a refrigeration system, two-stage throttling and middle air supplementing refrigeration cycles are often used, the control of the two-stage throttling devices is often based on independent control targets, the system fluctuation is often caused to be large and difficult to stabilize due to the fact that the control targets are based on different control targets, the actual running energy efficiency of a unit is also low, and unit abnormality such as suction liquid carrying or air supplementing liquid carrying is seriously caused even.
Therefore, how to make the operation of the refrigerating system unit more stable, effectively reduce the risks of air suction and air supplement and liquid entrainment is a technical problem to be solved at present.
Disclosure of Invention
The application provides a refrigeration system, which is used for solving the technical problem that the risks of liquid carrying during air suction and liquid carrying during air supplementing cannot be effectively reduced in the prior art, and comprises the following components:
the compressor is used for compressing the low-temperature low-pressure refrigerant gas into high-temperature high-pressure refrigerant gas and discharging the high-temperature high-pressure refrigerant gas to the condenser;
the economizer is used for separating the gaseous refrigerant from the liquid refrigerant, the gaseous refrigerant enters the compressor along the gas supplementing pipeline, and the liquid refrigerant enters the evaporator;
the first-stage throttling valve is arranged between the condenser and the economizer and used for throttling the refrigerant;
the second-stage throttle valve is arranged between the economizer and the evaporator and used for throttling the refrigerant;
a controller configured to:
acquiring the liquid level height of the economizer and the liquid level height of the evaporator;
and controlling the opening degrees of the primary throttle valve and the secondary throttle valve based on the liquid level height of the economizer, the liquid level height of the evaporator and the target liquid level height of the evaporator.
In some embodiments, the controller is further configured to:
when the liquid level height of the evaporator is larger than the target liquid level height of the evaporator, reducing the opening of the secondary throttle valve;
and when the liquid level height of the evaporator is smaller than the target liquid level height of the evaporator, increasing the opening degree of the secondary throttle valve.
In some embodiments, the controller is further configured to:
when the liquid level height of the economizer is larger than or equal to the negative deviation liquid level height and smaller than the positive deviation liquid level height, if the opening of the secondary throttle valve is increased, increasing the opening of the primary throttle valve;
when the liquid level height of the economizer is larger than or equal to the negative deviation liquid level height and smaller than the positive deviation liquid level height, if the opening of the secondary throttle valve is reduced, reducing the opening of the primary throttle valve;
wherein the negative deviation liquid level is the difference between the target liquid level of the economizer and a preset deviation height, and the positive deviation liquid level is the sum of the target liquid level of the economizer and the preset deviation height.
In some embodiments, the controller is further configured to:
when the liquid level height of the economizer is larger than or equal to a preset liquid level lower limit height and smaller than the negative deviation liquid level height, if the liquid level height of the evaporator is larger than the target liquid level height of the evaporator, the opening of the primary throttle valve is kept;
when the liquid level height of the economizer is larger than or equal to the preset liquid level lower limit height and smaller than the negative deviation liquid level height, if the liquid level height of the evaporator is smaller than or equal to the target liquid level height of the evaporator, increasing the opening of the primary throttle valve to a first preset opening.
In some embodiments, the controller is further configured to:
when the liquid level height of the economizer is larger than or equal to the positive deviation liquid level height and smaller than or equal to the preset liquid level upper limit height, if the liquid level height of the evaporator is larger than the target liquid level height of the evaporator, reducing the opening of the primary throttle valve to a fourth preset opening;
when the liquid level height of the economizer is larger than or equal to the positive deviation liquid level height and smaller than or equal to the preset liquid level upper limit height, if the liquid level height of the evaporator is smaller than or equal to the target liquid level height of the evaporator, the opening of the primary throttle valve is kept.
In some embodiments, the controller is further configured to:
when the liquid level height of the economizer is smaller than or equal to a preset liquid level lower limit height and the liquid level height of the evaporator is larger than the target liquid level height of the evaporator, increasing the opening of the primary throttle valve to the first preset opening;
and when the liquid level height of the economizer is smaller than or equal to the preset liquid level lower limit height and the liquid level height of the evaporator is smaller than or equal to the target liquid level height of the evaporator, increasing the opening of the primary throttle valve to a second preset opening.
In some embodiments, the controller is further configured to:
when the liquid level height of the economizer is larger than the preset liquid level upper limit height and the liquid level height of the evaporator is larger than the target liquid level height of the evaporator, reducing the opening of the primary throttle valve to a third preset opening;
and when the liquid level height of the economizer is larger than the preset liquid level upper limit height and the liquid level height of the evaporator is smaller than or equal to the target liquid level height of the evaporator, reducing the opening of the primary throttle valve to the fourth preset opening.
Accordingly, the present application also provides a control method of a two-stage throttle valve, which is applied to a refrigeration system including a compressor, an economizer, a one-stage throttle valve, a two-stage throttle valve, and a controller, wherein,
the first-stage throttle valve is arranged between the condenser and the economizer, and the second-stage throttle valve is arranged between the economizer and the evaporator;
the method comprises the following steps:
acquiring the liquid level height of the economizer and the liquid level height of the evaporator;
and controlling the opening degrees of the primary throttle valve and the secondary throttle valve based on the liquid level height of the economizer, the liquid level height of the evaporator and the target liquid level height of the evaporator.
In some embodiments, the opening degrees of the primary throttle valve and the secondary throttle valve are controlled according to the liquid level height of the economizer, the liquid level height of the evaporator and the target liquid level height of the evaporator, specifically:
when the liquid level height of the evaporator is larger than the target liquid level height of the evaporator, reducing the opening of the secondary throttle valve;
and when the liquid level height of the evaporator is smaller than the target liquid level height of the evaporator, increasing the opening degree of the secondary throttle valve.
In some embodiments, the opening degrees of the primary throttle valve and the secondary throttle valve are controlled according to the liquid level height of the economizer, the liquid level height of the evaporator and the target liquid level height of the evaporator, specifically:
when the liquid level height of the economizer is larger than or equal to the negative deviation liquid level height and smaller than the positive deviation liquid level height, if the opening of the secondary throttle valve is increased, increasing the opening of the primary throttle valve;
when the liquid level height of the economizer is larger than or equal to the negative deviation liquid level height and smaller than the positive deviation liquid level height, if the opening of the secondary throttle valve is reduced, reducing the opening of the primary throttle valve;
wherein the negative deviation liquid level is the difference between the target liquid level of the economizer and a preset deviation height, and the positive deviation liquid level is the sum of the target liquid level of the economizer and the preset deviation height.
Compared with the prior art, the application has the following beneficial effects:
the application discloses a refrigerating system and a control method of a two-stage throttle valve, wherein the refrigerating system comprises a compressor and an economizer, wherein the economizer is used for separating gaseous and liquid refrigerants; the first-stage throttling valve is arranged between the condenser and the economizer and used for throttling the refrigerant; the second-stage throttle valve is arranged between the economizer and the evaporator and used for throttling the refrigerant; a controller configured to: acquiring the liquid level height of the economizer and the liquid level height of the evaporator; and controlling the opening degree of the primary throttle valve and the opening degree of the secondary throttle valve based on the liquid level height of the economizer, the liquid level height of the evaporator and the target liquid level height of the evaporator, so that the operation of a refrigerating system unit is more stable, and the risks of liquid suction and liquid supplement are effectively reduced.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the description of the embodiments will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic structural diagram of a refrigeration system according to an embodiment of the present application;
fig. 2 is a flow chart of a control method of a two-stage throttle valve according to an embodiment of the present application.
Description of the reference numerals
1. A compressor 2, a condenser 3, an evaporator 4, an economizer 5, a primary throttle valve 6, and a secondary throttle valve.
Detailed Description
The following description of the embodiments of the present application will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present application, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.
In the description of the present application, it should be understood that the terms "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like indicate orientations or positional relationships based on the orientation or positional relationships shown in the drawings, merely to facilitate describing the present application and simplify the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present application.
The terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present application, unless otherwise indicated, the meaning of "a plurality" is two or more.
In the description of the present application, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present application will be understood in specific cases by those of ordinary skill in the art.
In the embodiment of the application, as shown in fig. 1, a gaseous refrigerant discharged from a compressor 1 enters a condenser 2, the gaseous refrigerant is condensed into a liquid refrigerant in the condenser 2, the liquid refrigerant is throttled by a first-stage throttle valve 5 and then becomes a two-phase fluid to enter an economizer 4, in the economizer 4, the gaseous refrigerant and the liquid refrigerant are separated, the gaseous refrigerant enters an intermediate air supplementing port of the compressor 1 along an air supplementing pipeline, the liquid refrigerant enters an evaporator 3 after being throttled by a second-stage throttle valve 6, the liquid refrigerant absorbs heat and evaporates in the evaporator 3 and becomes the gaseous refrigerant, and the gaseous refrigerant enters the compressor 1 along an air suction pipeline, so that one-time two-stage throttling and intermediate air supplementing refrigeration cycle is completed.
To further describe aspects of the present application, in one example of the present application, the refrigeration system includes:
a compressor 1 for compressing low-temperature low-pressure refrigerant gas into high-temperature high-pressure refrigerant gas and discharging the high-temperature high-pressure refrigerant gas to a condenser 2;
the economizer 4 is used for separating the gaseous refrigerant from the liquid refrigerant, the gaseous refrigerant enters the compressor 1 along the gas supplementing pipeline, and the liquid refrigerant enters the evaporator 3;
a first-stage throttle valve 5, which is disposed between the condenser 2 and the economizer 4, and is configured to throttle the refrigerant;
a secondary throttle valve 6 provided between the economizer 4 and the evaporator 3, for throttling the refrigerant;
a controller configured to:
acquiring the liquid level height of the economizer and the liquid level height of the evaporator;
and controlling the opening degrees of the primary throttle valve and the secondary throttle valve based on the liquid level height of the economizer, the liquid level height of the evaporator and the target liquid level height of the evaporator.
In this embodiment, the economizer may be a flash tank type economizer, or may be an economizer of another type, and a primary throttle valve is disposed between the condenser and the economizer for throttling the refrigerant before entering the economizer, and a secondary throttle valve is disposed between the economizer and the evaporator for throttling the refrigerant before entering the evaporator; the controller firstly obtains the liquid level heights of the economizer and the evaporator respectively, and then controls the opening degrees of the primary throttle valve and the secondary throttle valve according to the liquid level height of the economizer, the liquid level height of the evaporator and the target liquid level height of the evaporator. The target liquid level of the evaporator is the liquid level set during the working of the refrigerating system, and can be controlled by a user according to the needs. Optionally, the target evaporator level height may be associated with a set temperature of the refrigeration system, and when the user adjusts the set temperature of the refrigeration system, the target evaporator level height is also adjusted accordingly.
To accurately adjust the opening of the two-stage throttle valve, in some embodiments, the controller is further configured to:
when the liquid level height of the evaporator is larger than the target liquid level height of the evaporator, reducing the opening of the secondary throttle valve;
and when the liquid level height of the evaporator is smaller than the target liquid level height of the evaporator, increasing the opening degree of the secondary throttle valve.
In this embodiment, the opening degree of the secondary throttle valve is controlled by the liquid level height of the evaporator and the target liquid level height of the evaporator, and when the liquid level height of the evaporator is greater than the target liquid level height of the evaporator, the opening degree of the secondary throttle valve is reduced, so that the liquid level in the evaporator can be raised to the target liquid level of the evaporator; when the liquid level height of the evaporator is smaller than the target liquid level height of the evaporator, increasing the opening of the secondary throttle valve so that the liquid level in the evaporator can be reduced to the target liquid level of the evaporator; optionally, when the liquid level of the evaporator is equal to the target liquid level of the evaporator, the opening of the current secondary throttle valve is maintained unchanged.
It should be noted that the solution of the above preferred embodiment is only one specific implementation solution provided by the present application, and other methods for controlling the opening of the secondary throttle valve based on the liquid level height of the evaporator and the target liquid level height of the evaporator are all within the protection scope of the present application.
To accurately adjust the opening of the two-stage throttle valve, in some embodiments, the controller is further configured to:
when the liquid level height of the economizer is larger than or equal to the negative deviation liquid level height and smaller than the positive deviation liquid level height, if the opening of the secondary throttle valve is increased, increasing the opening of the primary throttle valve;
when the liquid level height of the economizer is larger than or equal to the negative deviation liquid level height and smaller than the positive deviation liquid level height, if the opening of the secondary throttle valve is reduced, reducing the opening of the primary throttle valve;
wherein the negative deviation liquid level is the difference between the target liquid level of the economizer and a preset deviation height, and the positive deviation liquid level is the sum of the target liquid level of the economizer and the preset deviation height.
In this embodiment, when the liquid level of the economizer is equal to or greater than the negative deviation liquid level and less than the positive deviation liquid level, the liquid level of the economizer is in a relatively moderate range, that is, the liquid level of the economizer is in the allowable positive and negative deviation, at this time, the adjustment trends of the primary throttle valve and the secondary throttle valve are kept consistent, when the opening of the secondary throttle valve is increased, the opening of the primary throttle valve is increased, and when the opening of the secondary throttle valve is decreased, the opening of the primary throttle valve is decreased, preferably, in order to reasonably control the primary throttle valve, the amplitude of the increase or decrease of the primary throttle valve is 50% of the amplitude of the increase or decrease of the secondary throttle valve. The negative deviation liquid level is the difference between the target liquid level of the economizer and the preset deviation height, the positive deviation liquid level is the sum of the target liquid level of the economizer and the preset deviation height, and the preset deviation height can be set according to actual conditions.
It should be noted that the solution of the above preferred embodiment is only one specific implementation solution provided by the present application, and other methods for controlling the opening of the two-stage throttle valve based on the liquid level of the economizer, the liquid level of the evaporator and the target liquid level of the evaporator are all within the protection scope of the present application.
To accurately adjust the opening of the two-stage throttle valve, in some embodiments, the controller is further configured to:
when the liquid level height of the economizer is larger than or equal to a preset liquid level lower limit height and smaller than the negative deviation liquid level height, if the liquid level height of the evaporator is larger than the target liquid level height of the evaporator, the opening of the primary throttle valve is kept;
when the liquid level height of the economizer is larger than or equal to the preset liquid level lower limit height and smaller than the negative deviation liquid level height, if the liquid level height of the evaporator is smaller than or equal to the target liquid level height of the evaporator, increasing the opening of the primary throttle valve to a first preset opening.
In this embodiment, when the liquid level of the economizer is greater than or equal to the preset liquid level lower limit height and less than the negative deviation liquid level height, it is indicated that the liquid level of the economizer is lower but does not reach the preset lower limit, and the liquid level of the evaporator needs to be considered comprehensively at this time, when the liquid level of the evaporator is greater than the target liquid level of the evaporator, the opening of the secondary throttle valve is reduced, the opening of the primary throttle valve is maintained, and the liquid level of the economizer is also gradually increased; the preset liquid level lower limit height can be set according to actual conditions, when the liquid level height of the evaporator is smaller than or equal to the target liquid level height of the evaporator, the opening of the secondary flow valve is kept unchanged or increased, at the moment, the opening of the primary throttle valve needs to be increased to a first preset opening, and the first preset opening can be obtained through experiments.
It should be noted that the solution of the above preferred embodiment is only one specific implementation solution provided by the present application, and other methods for controlling the opening of the two-stage throttle valve based on the liquid level of the economizer, the liquid level of the evaporator and the target liquid level of the evaporator are all within the protection scope of the present application.
To accurately control the opening of the two-stage throttle valve, in some embodiments, the controller is further configured to:
when the liquid level height of the economizer is larger than or equal to the positive deviation liquid level height and smaller than or equal to the preset liquid level upper limit height, if the liquid level height of the evaporator is larger than the target liquid level height of the evaporator, reducing the opening of the primary throttle valve to a fourth preset opening;
when the liquid level height of the economizer is larger than or equal to the positive deviation liquid level height and smaller than or equal to the preset liquid level upper limit height, if the liquid level height of the evaporator is smaller than or equal to the target liquid level height of the evaporator, the opening of the primary throttle valve is kept.
In this embodiment, when the liquid level of the economizer is greater than or equal to the positive deviation liquid level and less than or equal to the preset liquid level upper limit height, it is indicated that the liquid level of the economizer is higher but not exceeding the preset liquid level upper limit height, the liquid level of the evaporator needs to be considered comprehensively at this time, and when the liquid level of the evaporator is greater than the target liquid level of the evaporator, the opening degree of the secondary throttle valve is reduced, and at this time, in order to reduce the liquid level of the economizer, the opening degree of the primary throttle valve should be reduced to a fourth preset opening degree, which can be set according to practical situations, and the fourth preset opening degree can be obtained through experiments. When the liquid level of the evaporator is smaller than or equal to the target liquid level of the evaporator, the opening of the secondary throttle valve is increased or unchanged, and the opening of the primary throttle valve is kept.
It should be noted that the solution of the above preferred embodiment is only one specific implementation solution provided by the present application, and other methods for controlling the opening of the two-stage throttle valve based on the liquid level of the economizer, the liquid level of the evaporator and the target liquid level of the evaporator are all within the protection scope of the present application.
To accurately control the opening of the two-stage throttle valve, in some embodiments, the controller is further configured to:
when the liquid level height of the economizer is smaller than or equal to a preset liquid level lower limit height and the liquid level height of the evaporator is larger than the target liquid level height of the evaporator, increasing the opening of the primary throttle valve to the first preset opening;
and when the liquid level height of the economizer is smaller than or equal to the preset liquid level lower limit height and the liquid level height of the evaporator is smaller than or equal to the target liquid level height of the evaporator, increasing the opening of the primary throttle valve to a second preset opening.
In this embodiment, when the liquid level of the economizer is less than or equal to the preset lower limit liquid level, the liquid level of the economizer is low, the liquid level of the economizer needs to be raised while the liquid level of the evaporator is referred to, and when the liquid level of the evaporator is greater than the target liquid level of the evaporator, the opening of the secondary throttle valve is reduced, and the liquid level of the economizer is indirectly raised, but because the liquid level of the economizer is not above the normal lower limit liquid level, the opening of the primary throttle valve should be increased to the first preset opening; the preset lower limit height can be set according to practical situations, when the liquid level height of the evaporator is smaller than or equal to the target liquid level height of the evaporator, the opening of the secondary throttle valve is increased or kept unchanged at the moment, and in order to raise the liquid level height of the economizer, the opening of the primary throttle valve is increased to a second preset opening. The second preset opening degree may be obtained through experiments, and preferably, in order to reasonably raise the liquid level height of the economizer, the second preset opening degree is 1.5 times that of the first preset opening degree.
It should be noted that the solution of the above preferred embodiment is only one specific implementation solution provided by the present application, and other methods for controlling the opening of the two-stage throttle valve based on the liquid level of the economizer, the liquid level of the evaporator and the target liquid level of the evaporator are all within the protection scope of the present application.
To accurately control the opening of the two-stage throttle valve, in some embodiments, the controller is further configured to:
when the liquid level height of the economizer is larger than the preset liquid level upper limit height and the liquid level height of the evaporator is larger than the target liquid level height of the evaporator, reducing the opening of the primary throttle valve to a third preset opening;
and when the liquid level height of the economizer is larger than the preset liquid level upper limit height and the liquid level height of the evaporator is smaller than or equal to the target liquid level height of the evaporator, reducing the opening of the primary throttle valve to the fourth preset opening.
In this embodiment, when the liquid level of the economizer is greater than the preset upper liquid level limit, the liquid level of the economizer is higher, the liquid level of the evaporator needs to be reduced while referring to the liquid level of the evaporator, when the liquid level of the evaporator is greater than the target liquid level of the evaporator, the opening of the secondary throttle valve is reduced, in order to increase the liquid level falling speed of the evaporator, the opening of the primary throttle valve is reduced to a third preset opening, which can be obtained through experiments, and when the liquid level of the evaporator is less than or equal to the target liquid level of the evaporator, the opening of the secondary throttle valve is increased or kept unchanged, and at this time, the opening of the primary throttle valve is reduced to a fourth preset opening. Preferably, in order to reasonably adjust the falling speed of the liquid level height of the economizer, the third preset opening is 1.5 times of the fourth preset opening.
It should be noted that the solution of the above preferred embodiment is only one specific implementation solution provided by the present application, and other methods for controlling the opening of the two-stage throttle valve based on the liquid level of the economizer, the liquid level of the evaporator and the target liquid level of the evaporator are all within the protection scope of the present application.
The application discloses a refrigerating system and a control method of a two-stage throttle valve, wherein the refrigerating system comprises a compressor and an economizer, wherein the economizer is used for separating gaseous and liquid refrigerants, the gaseous refrigerants enter the compressor along a gas supplementing pipeline, and the liquid refrigerants enter an evaporator; the first-stage throttling valve is arranged between the condenser and the economizer and used for throttling the refrigerant; the second-stage throttle valve is arranged between the economizer and the evaporator and used for throttling the refrigerant; a controller configured to: acquiring the liquid level height of the economizer and the liquid level height of the evaporator; the opening degree of the primary throttle valve and the opening degree of the secondary throttle valve are controlled based on the liquid level height of the economizer, the liquid level height of the evaporator and the target liquid level height of the evaporator, so that the refrigerating system unit operates more stably and always operates under the optimal working condition, and the risks of liquid suction and liquid supplement are effectively reduced.
In order to further explain the technical idea of the present application, the present application also provides a control method of a two-stage throttle valve, which is applied to a refrigeration system including a compressor, an economizer, a first-stage throttle valve, a second-stage throttle valve and a controller, wherein the first-stage throttle valve is disposed between a condenser and the economizer, the second-stage throttle valve is disposed between the economizer and an evaporator, as shown in fig. 2, the specific steps of the method are as follows:
s201, acquiring the liquid level height of the economizer and the liquid level height of the evaporator.
In this step, the liquid level heights of the economizer and the evaporator are obtained first, and alternatively, the liquid level heights of the economizer and the evaporator can be obtained by arranging a liquid level meter in the economizer and the evaporator.
S202, controlling the opening degrees of the primary throttle valve and the secondary throttle valve based on the liquid level height of the economizer, the liquid level height of the evaporator and the target liquid level height of the evaporator.
In this step, after the liquid level heights of the economizer and the evaporator are obtained, the opening degrees of the primary throttle valve and the secondary throttle valve are controlled according to the liquid level height of the economizer, the liquid level height of the evaporator and the target liquid level height of the evaporator, wherein the target liquid level height of the evaporator can be the liquid level height set by a user or can be automatically generated according to the operation temperature of the refrigeration system regulated by the user.
In order to accurately control the opening degrees of the secondary throttle valve, in some embodiments, the opening degrees of the primary throttle valve and the secondary throttle valve are controlled based on the liquid level height of the economizer, the liquid level height of the evaporator and the target liquid level height of the evaporator, specifically:
when the liquid level height of the evaporator is larger than the target liquid level height of the evaporator, reducing the opening of the secondary throttle valve;
and when the liquid level height of the evaporator is smaller than the target liquid level height of the evaporator, increasing the opening degree of the secondary throttle valve.
Specifically, when the liquid level of the evaporator is greater than the target liquid level of the evaporator, the opening of the secondary throttle valve is reduced, so that the liquid level of the evaporator is reduced to the target liquid level of the evaporator, and when the liquid level of the evaporator is less than the target liquid level of the evaporator, the opening of the secondary throttle valve is increased, so that the liquid level of the evaporator is increased to the target liquid level of the evaporator. Optionally, when the liquid level height of the evaporator is equal to the target liquid level height of the evaporator, the opening degree of the secondary throttle valve is maintained.
It should be noted that the solution of the above preferred embodiment is only one specific implementation solution provided by the present application, and other methods for controlling the opening of the secondary throttle valve based on the liquid level height of the evaporator and the target liquid level height of the evaporator are all within the protection scope of the present application.
In order to accurately control the opening degrees of the two-stage throttle valve, in some embodiments, the opening degrees of the primary throttle valve and the secondary throttle valve are controlled based on the liquid level height of the economizer, the liquid level height of the evaporator and the target liquid level height of the evaporator, specifically:
when the liquid level height of the economizer is larger than or equal to the negative deviation liquid level height and smaller than the positive deviation liquid level height, if the opening of the secondary throttle valve is increased, increasing the opening of the primary throttle valve;
when the liquid level height of the economizer is larger than or equal to the negative deviation liquid level height and smaller than the positive deviation liquid level height, if the opening of the secondary throttle valve is reduced, reducing the opening of the primary throttle valve;
wherein the negative deviation liquid level is the difference between the target liquid level of the economizer and a preset deviation height, and the positive deviation liquid level is the sum of the target liquid level of the economizer and the preset deviation height.
Specifically, when the liquid level of the economizer is greater than or equal to the negative deviation liquid level and less than the positive deviation liquid level, the liquid level of the economizer is in a relatively moderate range, i.e., the liquid level of the economizer is in the allowable positive and negative deviation, at this time, the adjustment trends of the primary throttle valve and the secondary throttle valve are kept consistent, when the opening of the secondary throttle valve is increased, the opening of the primary throttle valve is increased, and when the opening of the secondary throttle valve is decreased, the opening of the primary throttle valve is decreased, preferably, the amplitude of the increase or decrease of the primary throttle valve is 50% of the amplitude of the increase or decrease of the secondary throttle valve. The negative deviation liquid level is the difference between the target liquid level of the economizer and the preset deviation height, the positive deviation liquid level is the sum of the target liquid level of the economizer and the preset deviation height, and the preset deviation height can be set according to actual conditions.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present application, and are not limiting; although the application has been described in detail with reference to the foregoing embodiments, it will be appreciated by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not drive the essence of the corresponding technical solutions to depart from the spirit and scope of the technical solutions of the embodiments of the present application.
Claims (6)
1. A refrigeration system, comprising:
the compressor is used for compressing the low-temperature low-pressure refrigerant gas into high-temperature high-pressure refrigerant gas and discharging the high-temperature high-pressure refrigerant gas to the condenser;
the economizer is used for separating the gaseous refrigerant from the liquid refrigerant, the gaseous refrigerant enters the compressor along the gas supplementing pipeline, and the liquid refrigerant enters the evaporator;
the first-stage throttling valve is arranged between the condenser and the economizer and used for throttling the refrigerant;
the second-stage throttle valve is arranged between the economizer and the evaporator and used for throttling the refrigerant;
a controller configured to:
acquiring the liquid level height of the economizer and the liquid level height of the evaporator;
controlling the opening degrees of the primary throttle valve and the secondary throttle valve based on the liquid level height of the economizer, the liquid level height of the evaporator and the target liquid level height of the evaporator;
wherein the controller is further configured to:
when the liquid level height of the evaporator is larger than the target liquid level height of the evaporator, reducing the opening of the secondary throttle valve;
when the liquid level height of the evaporator is smaller than the target liquid level height of the evaporator, increasing the opening of the secondary throttle valve;
wherein the controller is further configured to:
when the liquid level height of the economizer is larger than or equal to the negative deviation liquid level height and smaller than the positive deviation liquid level height, if the opening of the secondary throttle valve is increased, increasing the opening of the primary throttle valve;
when the liquid level height of the economizer is larger than or equal to the negative deviation liquid level height and smaller than the positive deviation liquid level height, if the opening of the secondary throttle valve is reduced, reducing the opening of the primary throttle valve;
wherein the negative deviation liquid level is the difference between the target liquid level of the economizer and a preset deviation height, and the positive deviation liquid level is the sum of the target liquid level of the economizer and the preset deviation height.
2. The refrigeration system of claim 1, wherein the controller is further configured to:
when the liquid level height of the economizer is larger than or equal to a preset liquid level lower limit height and smaller than the negative deviation liquid level height, if the liquid level height of the evaporator is larger than the target liquid level height of the evaporator, the opening of the primary throttle valve is kept;
when the liquid level height of the economizer is larger than or equal to the preset liquid level lower limit height and smaller than the negative deviation liquid level height, if the liquid level height of the evaporator is smaller than or equal to the target liquid level height of the evaporator, increasing the opening of the primary throttle valve to a first preset opening.
3. The refrigeration system of claim 1, wherein the controller is further configured to:
when the liquid level height of the economizer is larger than or equal to the positive deviation liquid level height and smaller than or equal to the preset liquid level upper limit height, if the liquid level height of the evaporator is larger than the target liquid level height of the evaporator, reducing the opening of the primary throttle valve to a fourth preset opening;
when the liquid level height of the economizer is larger than or equal to the positive deviation liquid level height and smaller than or equal to the preset liquid level upper limit height, if the liquid level height of the evaporator is smaller than or equal to the target liquid level height of the evaporator, the opening of the primary throttle valve is kept.
4. The refrigeration system of claim 1, wherein the controller is further configured to:
when the liquid level height of the economizer is smaller than or equal to a preset liquid level lower limit height and the liquid level height of the evaporator is larger than the target liquid level height of the evaporator, increasing the opening of the primary throttle valve to a first preset opening;
and when the liquid level height of the economizer is smaller than or equal to the preset liquid level lower limit height and the liquid level height of the evaporator is smaller than or equal to the target liquid level height of the evaporator, increasing the opening of the primary throttle valve to a second preset opening.
5. The refrigeration system of claim 1, wherein the controller is further configured to:
when the liquid level height of the economizer is larger than the preset liquid level upper limit height and the liquid level height of the evaporator is larger than the target liquid level height of the evaporator, reducing the opening of the primary throttle valve to a third preset opening;
and when the liquid level height of the economizer is larger than the preset liquid level upper limit height and the liquid level height of the evaporator is smaller than or equal to the target liquid level height of the evaporator, reducing the opening of the primary throttle valve to a fourth preset opening.
6. A control method of a two-stage throttle valve is characterized in that the method is applied to a refrigerating system comprising a compressor, an economizer, a one-stage throttle valve, a two-stage throttle valve and a controller, wherein,
the first-stage throttle valve is arranged between the condenser and the economizer, and the second-stage throttle valve is arranged between the economizer and the evaporator;
the method comprises the following steps:
acquiring the liquid level height of the economizer and the liquid level height of the evaporator;
controlling the opening degrees of the primary throttle valve and the secondary throttle valve based on the liquid level height of the economizer, the liquid level height of the evaporator and the target liquid level height of the evaporator;
the opening degrees of the primary throttle valve and the secondary throttle valve are controlled based on the liquid level height of the economizer, the liquid level height of the evaporator and the target liquid level height of the evaporator, and specifically are as follows:
when the liquid level height of the evaporator is larger than the target liquid level height of the evaporator, reducing the opening of the secondary throttle valve;
when the liquid level height of the evaporator is smaller than the target liquid level height of the evaporator, increasing the opening of the secondary throttle valve;
the opening degrees of the primary throttle valve and the secondary throttle valve are controlled based on the liquid level height of the economizer, the liquid level height of the evaporator and the target liquid level height of the evaporator, and specifically are as follows:
when the liquid level height of the economizer is larger than or equal to the negative deviation liquid level height and smaller than the positive deviation liquid level height, if the opening of the secondary throttle valve is increased, increasing the opening of the primary throttle valve;
when the liquid level height of the economizer is larger than or equal to the negative deviation liquid level height and smaller than the positive deviation liquid level height, if the opening of the secondary throttle valve is reduced, reducing the opening of the primary throttle valve;
wherein the negative deviation liquid level is the difference between the target liquid level of the economizer and a preset deviation height, and the positive deviation liquid level is the sum of the target liquid level of the economizer and the preset deviation height.
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