CN112556220A - Unit and operation control method thereof - Google Patents
Unit and operation control method thereof Download PDFInfo
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- CN112556220A CN112556220A CN202011420322.3A CN202011420322A CN112556220A CN 112556220 A CN112556220 A CN 112556220A CN 202011420322 A CN202011420322 A CN 202011420322A CN 112556220 A CN112556220 A CN 112556220A
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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
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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
- F25B49/00—Arrangement or mounting of control or safety devices
- F25B49/02—Arrangement or mounting of control or safety devices for compression type machines, plants or systems
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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
- F25B2500/00—Problems to be solved
- F25B2500/13—Vibrations
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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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- Air Conditioning Control Device (AREA)
Abstract
The invention discloses a unit and an operation control method thereof. Wherein, this unit includes: compressor, condenser, expansion valve and evaporimeter still include: the throttle valve is arranged on a pipeline between the evaporator and the compressor, and the opening degree of the throttle valve is used for controlling the low-pressure of the unit; and the controller is connected with the throttle valve and is used for controlling the opening of the throttle valve according to the high-pressure and low-pressure of the unit so as to adjust the low-pressure. The invention can improve the problem of surge or blockage of the compressor and improve the operation stability of the unit.
Description
Technical Field
The invention relates to the technical field of units, in particular to a unit and an operation control method thereof.
Background
The compressor is one of important components in a large-scale water chilling unit (such as a water chilling unit) as a driving device of the unit, and the reliability and the stability of the operation of the compressor are very important. The magnetic suspension centrifugal compressor has the characteristics of high rotating speed, high efficiency, no need of lubricating oil and the like, and plays an important role in the field of the existing large-scale air conditioner.
When the magnetic suspension centrifugal compressor is applied to the air-cooled water chilling unit, the compressor is easy to surge or block due to the fact that the environment where the water chilling unit is applied is severe, and stability is reduced.
Aiming at the problem that the compressor is easy to surge or block to cause stability reduction in the prior art, an effective solution is not provided at present.
Disclosure of Invention
The embodiment of the invention provides a unit and an operation control method thereof, which aim to solve the problem that the stability is reduced because a compressor is easy to surge or block in the prior art.
In order to solve the above technical problems, the present invention provides a machine set, which includes a compressor, a condenser, an expansion valve, and an evaporator, and is characterized by further including:
the throttle valve is arranged on a pipeline between the evaporator and the compressor, and the opening degree of the throttle valve is used for controlling the low-pressure of the unit;
and the controller is connected with the throttle valve and is used for controlling the opening of the throttle valve according to the high-pressure and low-pressure of the unit so as to adjust the low-pressure.
Further, the controller includes:
a first control unit configured to control an opening degree of the throttle valve to increase the low pressure when a pressure difference between the high pressure and the low pressure is greater than a first threshold;
a second control unit configured to control the opening degree of the throttle valve to be kept constant so as to keep the low-pressure constant when the differential pressure is less than or equal to the first threshold and greater than or equal to a second threshold;
a third control unit configured to control an opening degree of the throttle valve to be decreased to lower the low pressure when the differential pressure is smaller than the second threshold value.
Further, the unit further includes: the first temperature sensor is arranged at the inlet end of the evaporator and used for detecting the inlet temperature of a heat exchange medium of the evaporator; the second temperature sensor is arranged in the environment and used for detecting the environment temperature;
the controller further includes: and the threshold setting unit is used for setting the first threshold and the second threshold according to the inlet temperature of the heat exchange medium, the ambient temperature and the characteristic curve of the compressor.
Further, the unit further includes:
the first pressure sensor is arranged on a pipeline between the compressor and the condenser and used for detecting the high-pressure;
and the second pressure sensor is arranged on a pipeline between the throttling valve and the compressor and used for detecting the low-pressure.
Further, the unit further includes:
the pressure balance pipeline is arranged between the exhaust end and the suction end of the compressor and connected with the condenser, the expansion valve and a branch formed by the evaporator in parallel, a pressure balance valve is arranged on the pressure balance pipeline, and the opening degree of the pressure balance valve is used for adjusting the pressure difference between the high pressure and the low pressure.
The invention also provides an operation control method, which is applied to the unit and comprises the following steps:
acquiring high pressure and low pressure of a unit;
adjusting an opening degree of a throttle valve to adjust the low pressure according to a pressure difference between the high pressure and the low pressure; the throttling valve is arranged on a pipeline between an evaporator and a compressor of the unit.
Further, adjusting the low pressure according to a pressure differential between the high pressure and the low pressure comprises:
controlling an opening degree of a throttle valve to increase the low pressure if a pressure difference between the high pressure and the low pressure is greater than a first threshold;
if the differential pressure is less than or equal to the first threshold value and greater than or equal to a second threshold value, controlling the opening of the throttle valve to be kept unchanged so as to keep the low-pressure unchanged;
and if the differential pressure is smaller than the second threshold value, controlling the opening degree of the throttle valve to be reduced so as to reduce the low-pressure.
Further, before adjusting the low pressure according to a pressure difference between the high pressure and the low pressure, the method further comprises:
acquiring the inlet temperature and the ambient temperature of a heat exchange medium of an evaporator;
and determining the first threshold value and the second threshold value according to the inlet temperature of the heat exchange medium, the ambient temperature and the characteristic curve of the compressor.
Further, after determining the first threshold and the second threshold according to the inlet temperature of the heat exchange medium, the ambient temperature, and the characteristic curve of the compressor, the method further includes:
and updating the first threshold value and the second threshold value according to the inlet temperature of the heat exchange medium, the ambient temperature and the characteristic curve of the compressor every first preset time interval.
Further, after adjusting the low pressure according to a pressure difference between the high pressure and the low pressure, the method further comprises:
and after a second preset time, triggering again to adjust the opening of the throttle valve according to the pressure difference between the high pressure and the low pressure so as to adjust the low pressure.
Further, before adjusting the opening of the throttle valve to adjust the low pressure according to a pressure difference between the high pressure and the low pressure, the method further includes:
judging whether the throttle valve reaches the maximum opening or the minimum opening;
if yes, adjusting the opening degree of a pressure balance valve according to the pressure difference between the high pressure and the low pressure to adjust the pressure difference; the pressure balance valve is arranged on a pressure balance pipeline, and the pressure balance pipeline is arranged between the exhaust end and the suction end of the compressor.
Further, adjusting an opening degree of a pressure balance valve to adjust the differential pressure according to the differential pressure of the high pressure and the low pressure includes:
increasing the opening degree of the pressure balancing valve to reduce a differential pressure if the differential pressure between the high pressure and the low pressure is greater than a first threshold value;
if the pressure difference between the high pressure and the low pressure is less than a second threshold, the opening of the pressure balancing valve is decreased to increase the pressure difference.
The present invention also provides a computer-readable storage medium on which a computer program is stored, which when executed by a processor implements the above-described operation control method.
By applying the technical scheme of the invention, the throttle valve is arranged between the evaporator and the compressor, and the opening of the throttle valve is controlled by the controller according to the high pressure and the low pressure of the unit to adjust the low pressure, so that the problem of surge or blockage of the compressor can be solved, and the operation stability of the unit is improved.
Drawings
FIG. 1 is a block diagram of an assembly according to an embodiment of the invention;
fig. 2 is an internal structural view of a controller according to an embodiment of the present invention;
FIG. 3 is a block diagram of an assembly according to another embodiment of the present invention;
FIG. 4 is a flow chart of an operation control method according to an embodiment of the present invention;
fig. 5 is a flowchart of an operation control method according to another embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer, the present invention will be described in further detail with reference to the accompanying drawings, and it is apparent that the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The terminology used in the embodiments of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in the examples of the present invention and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise, and "a plurality" typically includes at least two.
It should be understood that the term "and/or" as used herein is merely one type of association that describes an associated object, meaning that three relationships may exist, e.g., a and/or B may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship.
It should be understood that although the terms first, second, etc. may be used to describe the thresholds in embodiments of the present invention, the thresholds should not be limited to these terms. These terms are only used to distinguish between different thresholds. For example, the first threshold may also be referred to as a second threshold, and similarly, the second threshold may also be referred to as a first threshold, without departing from the scope of embodiments of the present invention.
The words "if", as used herein, may be interpreted as "at … …" or "at … …" or "in response to a determination" or "in response to a detection", depending on the context. Similarly, the phrases "if determined" or "if detected (a stated condition or event)" may be interpreted as "when determined" or "in response to a determination" or "when detected (a stated condition or event)" or "in response to a detection (a stated condition or event)", depending on the context.
It is also noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that an article or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such article or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in the article or device in which the element is included.
Alternative embodiments of the present invention are described in detail below with reference to the accompanying drawings.
Example 1
This embodiment provides a unit, and fig. 1 is a structural diagram of a unit according to an embodiment of the present invention, as shown in fig. 1, the unit includes a compressor 1, a condenser 2, an expansion valve 3, and an evaporator 4, a discharge end of the compressor 1 is communicated with an inlet end of the condenser 2, an outlet end of the condenser 2 is communicated with an inlet end of the evaporator 4 through the electronic expansion valve 3, and an outlet end of the evaporator 4 is communicated with a suction end of the compressor 1.
The heat exchange medium flow path of the unit is as follows: discharge end of compressor 1 → condenser 2 → electronic expansion valve 3 → evaporator 4 → suction end of compressor 1.
In order to realize the regulation of the low pressure, the above-mentioned unit further comprises: the throttle valve 5 is arranged on a pipeline between the evaporator 4 and the compressor 1, and the opening degree of the throttle valve 5 is used for controlling the low-pressure of the unit; and the controller 6 is connected with the throttle valve 5 and is used for controlling the opening of the throttle valve 5 according to the high-pressure and the low-pressure of the unit so as to regulate the low-pressure. The throttle valve 5 may be an electrically operated valve that can be automatically controlled by a controller.
The unit of this embodiment through set up the choke valve between evaporimeter and compressor to through the controller, according to the high pressure of unit and the aperture of low pressure control choke valve, with the low pressure of adjusting, can improve the problem of compressor surge or jam, improve unit operating stability.
Example 2
In this embodiment, another unit is provided, fig. 2 is an internal structure diagram of a controller according to an embodiment of the present invention, and in order to match an opening degree adjustment amount manner of a low pressure with a current working condition, as shown in fig. 2, the controller 6 includes: the first control unit 61 is used for controlling the opening of the throttle valve to increase so as to improve the low-pressure when the pressure difference between the high-pressure and the low-pressure of the unit is greater than a first threshold value; a second control unit 62 for controlling the opening degree of the throttle valve to be kept constant so that the low-pressure is kept constant when the differential pressure is less than or equal to the first threshold value and greater than or equal to the second threshold value; a third control unit 63 for controlling the opening of the throttle valve to decrease to lower the low pressure when the differential pressure is less than the second threshold value. And a threshold setting unit 64 for setting a first threshold and a second threshold according to the inlet temperature of the heat exchange medium, the ambient temperature, and the characteristic curve of the compressor.
Fig. 3 is a structural diagram of an assembly according to another embodiment of the present invention, in which since the threshold setting unit 64 needs to set the first threshold and the second threshold, according to the inlet temperature and the ambient temperature of the heat exchange medium, in order to obtain the inlet temperature and the ambient temperature of the heat exchange medium, as shown in fig. 3, the assembly further includes: a first temperature sensor S1 provided at an inlet end (not shown in the figure) of the evaporator 4 for detecting an inlet temperature of the heat exchange medium of the evaporator 4; and a second temperature sensor S2 disposed in the environment for detecting an ambient temperature.
In order to obtain the high pressure and the low pressure of the unit, as shown in fig. 3, the unit further includes: a first pressure sensor S3 disposed on a pipe between the compressor and the condenser, for detecting a high pressure; and a second pressure sensor S4 provided on a pipe between the throttle valve 5 and the compressor 1 for detecting a low pressure.
In order to continuously adjust the differential pressure in a situation where the controller controls the opening of the throttle valve 5 according to the high pressure and the low pressure of the unit to adjust the low pressure, it may be necessary to increase the low pressure but the opening of the throttle valve 5 is opened to the maximum, or it is necessary to decrease the low pressure but the opening of the throttle valve 5 is opened to the minimum, as shown in fig. 3:
the pressure balance pipeline is arranged between the exhaust end and the suction end of the compressor and is connected in parallel with a branch formed by the condenser 2, the expansion valve 3 and the evaporator 4, a pressure balance valve is arranged on the pressure balance pipeline, the opening degree of the pressure balance valve is used for adjusting the pressure difference between high pressure and low pressure, and specifically, the opening degree of the pressure balance valve is increased to reduce the pressure difference when the pressure difference between the high pressure and the low pressure is greater than a first threshold value; and when the pressure difference between the high pressure and the low pressure is smaller than a second threshold value, the opening degree of the pressure balance valve is reduced to increase the pressure difference.
Example 3
The present embodiment provides an operation control method applied to the above-mentioned unit, and fig. 4 is a flowchart of the operation control method according to the embodiment of the present invention, as shown in fig. 4, the method includes:
and S101, acquiring high pressure and low pressure of the unit.
When the compressor surges, the pressure difference between the high pressure and the low pressure of the unit can be increased, and when the compressor is blocked, the pressure difference between the high pressure and the low pressure of the unit can be reduced, so that whether the unit surges or blocks can be judged through the high pressure and the low pressure of the unit.
S102, adjusting the opening of a throttle valve according to the pressure difference between the high pressure and the low pressure to adjust the low pressure; the throttle valve is arranged on a pipeline between an evaporator and a compressor of the unit.
When the compressor surges to cause the pressure difference between the high pressure and the low pressure of the unit to rise, the pressure difference can be reduced by a method of rising the low pressure; when the compressor is clogged to cause a decrease in the differential pressure between the high pressure and the low pressure of the unit, the differential pressure may be increased by a method of decreasing the low pressure, and in particular, the low pressure may be adjusted by adjusting the opening degree of the throttle valve.
According to the operation control method, the high pressure and the low pressure of the unit are obtained, and the opening of the throttle valve on the pipeline between the evaporator and the compressor of the unit is adjusted through the controller according to the pressure difference between the high pressure and the low pressure so as to adjust the low pressure, so that the problem of surging or blocking of the compressor can be solved, and the operation stability of the unit is improved.
Example 4
In this embodiment, another operation control method is provided, in order to match the opening degree adjustment amount mode of the low pressure with the current working condition, the step S102 specifically includes:
if the pressure difference between the high pressure and the low pressure is greater than the first threshold value, the current surge working condition is indicated, and the opening of the throttle valve is controlled to be increased at the moment so as to improve the low pressure, reduce the pressure difference between the high pressure and the low pressure and improve the surge problem; if the differential pressure is smaller than or equal to the first threshold value and larger than or equal to the second threshold value, the unit is in a normal operation state, and the opening of the throttle valve is controlled to be kept unchanged so as to keep the low-pressure unchanged; and if the differential pressure is smaller than the second threshold value, the opening of the throttle valve is controlled to be reduced so as to reduce the low-pressure, increase the differential pressure between the high-pressure and the low-pressure and improve the blockage problem. It should be noted that, in the initial state, the throttle valve is opened by a preset opening degree, for example, 50% of the maximum opening degree, and then, the throttle valve is adjusted based on the preset opening degree.
Since the surge threshold value and the blockage threshold value are different in different operation parameters, the first threshold value and the second threshold value need to be set according to the actual operation condition, and therefore, before executing step S102, the method further includes: acquiring the inlet temperature and the ambient temperature of a heat exchange medium of an evaporator; and determining the first threshold value and the second threshold value according to the inlet temperature of the heat exchange medium of the evaporator, the ambient temperature and the characteristic curve of the compressor.
Under the specific working condition of running of the water chilling unit, when the evaporation temperature t0 is constant, the unit refrigerating capacity of the heat exchange medium is changed due to the change of the condensation temperature tk, and the unit mass isentropic work of the heat exchange medium is approximately considered to be proportional to the temperature difference tk-t 0. For the air-cooled water chilling unit, the evaporation temperature is related to the inlet temperature of the heat exchange medium of the evaporator, and the condensation temperature is related to the outdoor environment temperature. Therefore, the evaporation temperature t0 can be obtained according to the inlet temperature of the heat exchange medium of the evaporator, the condensation temperature tk can be obtained according to the outdoor environment temperature, and a first threshold value P1 of the pressure difference when the compressor generates surge can be obtained according to the evaporation temperature t0 and the condensation temperature tk by combining the characteristic curve of the compressor, or a second threshold value P2 of the pressure difference when the compressor generates blockage and a mathematical model expression f (tk, t0) of the evaporation temperature and the condensation temperature of the unit under the specific working condition. According to the formula, the controller of the unit can obtain the values of the parameters t0 and tk according to the detected inlet temperature and the ambient temperature of the heat exchange medium of the evaporator, and automatically calculate to obtain a second threshold value of the pressure difference under the working condition of compressor blockage and a first threshold value of the pressure difference under the surge working condition.
Since the actual operating state of the unit is changed in real time, and the first threshold and the second threshold should be changed, after determining the first threshold and the second threshold according to the inlet temperature of the heat exchange medium, the ambient temperature, and the characteristic curve of the compressor, the method further includes: and updating the first threshold value and the second threshold value according to the inlet temperature of the heat exchange medium, the ambient temperature and the characteristic curve of the compressor every first preset time interval.
Because the high pressure and the low pressure of the unit are changed, in order to ensure the control accuracy, the regulation is needed to be carried out again at regular intervals, therefore, after the low pressure is regulated according to the pressure difference between the high pressure and the low pressure, the method also comprises the following steps: after the second preset time, the opening of the throttle valve is triggered again to adjust the low pressure according to the pressure difference between the high pressure and the low pressure.
The first preset time length and the second preset time length can be the same or different, when the first preset time length is different from the second preset time length, if the opening of the throttle valve is adjusted according to the pressure difference between the high pressure and the low pressure to adjust the low pressure by triggering again, the first threshold value and the second threshold value are not updated in time, and the first threshold value and the second threshold value which are updated last time are adopted for comparison.
In order to continue to adjust the differential pressure in the above-mentioned situation, the controller may further include, before adjusting the opening of the throttle valve to adjust the low pressure according to the differential pressure between the high pressure and the low pressure, the method further including: judging whether the throttle valve reaches the maximum opening or the minimum opening; if yes, adjusting the opening degree of the pressure balance valve according to the pressure difference between the high pressure and the low pressure to adjust the pressure difference; wherein, pressure balance valve sets up on pressure balance pipeline, and pressure balance pipeline sets up between the exhaust end of compressor and the end of breathing in, specifically, according to the pressure differential of high-pressure and low-pressure, adjusts pressure balance valve's aperture in order to adjust pressure differential, includes: if the differential pressure between the high pressure and the low pressure is greater than the first threshold value and the opening degree of the throttle valve has reached the maximum value, increasing the opening degree of the pressure balance valve to reduce the differential pressure between the high pressure and the low pressure; if the differential pressure between the high pressure and the low pressure is less than the second threshold value and the opening degree of the throttle valve has reached the minimum value, the opening degree of the pressure balance valve is decreased to increase the differential pressure.
Example 5
The present embodiment provides another assembly, which is an air-cooled magnetic suspension centrifugal chiller, and the structure of the assembly is as described in fig. 3 mentioned above, and the assembly includes: the air conditioner comprises a compressor 1, a condenser 2, an electronic expansion valve 3, an evaporator 4 and a throttle valve 5, wherein the throttle valve 5 is arranged on an air suction pipeline between the evaporator 4 and the compressor 1, and the throttle valve 5 can be an electric valve which can be automatically controlled by a controller.
The heat exchange medium flow path of the unit is as follows: discharge end of compressor 1 → condenser 2 → electronic expansion valve 3 → evaporator 4 → throttle valve 5 → suction end of compressor 1.
In this embodiment, in order to balance the pressures at the discharge end and the suction end of the compressor, a pressure balance pipeline 7 is further provided, which is specifically provided between the discharge end and the suction end of the compressor 1, and is connected in parallel with the branch formed by the condenser 2, the expansion valve 3 and the evaporator 4, a pressure balance valve 8 is provided on the pressure balance pipeline, the pressures at the discharge end and the suction end of the compressor are further adjusted by adjusting the opening degree of the pressure balance valve 8, specifically, if the pressure difference between the high pressure of the unit and the low pressure of the unit is too large, the opening degree of the pressure balance valve 8 is increased to reduce the pressure difference, and if the pressure difference between the high pressure of the unit and the low pressure of the unit is too small, the opening degree of the pressure balance valve 8 is decreased to increase the pressure difference.
The present embodiment further provides another operation control method, which is applied to the air-cooled magnetic levitation centrifugal chiller, fig. 5 is a flowchart of an operation control method according to another embodiment of the present invention, as shown in fig. 5, the method includes:
s1, the initial opening degree of the throttle valve is set to a preset opening degree while the compressor is turned on. For example, the initial opening degree of the throttle valve is set to 50% of the maximum opening degree.
S2, obtaining a first threshold P1 of the pressure difference under the surge working condition and a second threshold P2 of the pressure difference under the blockage working condition of the compressor according to the inlet temperature of the heat exchange medium of the evaporator, the ambient temperature and the characteristic curve of the compressor.
The performance curves of the magnetic suspension centrifugal refrigeration compressor and the general centrifugal compressor are basically consistent in shape and form, and only the expressed parameters are different. For example, the outlet pressure is replaced by the condensing temperature tk, and the volumetric flow qv or the mass flow qm of the heat exchange medium is replaced by the refrigerating capacity Φ. Under the specific working condition of running of the water chilling unit, when the evaporation temperature t0 is constant, the unit refrigerating capacity of the heat exchange medium is changed due to the change of the condensation temperature tk, and the unit mass isentropic work of the heat exchange medium is approximately considered to be proportional to the temperature difference tk-t 0. For the air-cooled water chilling unit, the evaporation temperature is related to the inlet temperature of the heat exchange medium of the evaporator, and the condensation temperature is related to the ambient temperature. Thus, the evaporation temperature t0 can be obtained from the inlet temperature of the heat exchange medium of the evaporator, the condensation temperature tk can be obtained from the outdoor ambient temperature, and specifically, the evaporation temperature t0 ═ tw1+ ((1+ Pe/Φ 0)/((1-e ^ - α k) × Wm)) × Φ 1 from the evaporation temperature t0 and the condensation temperature tk; wm qmw cw, α K1 a 1/Wm; wherein tw1 is the inlet temperature of the heat exchange medium of the evaporator; qmw is the mass flow of heat exchange medium; cw is the specific heat capacity of the heat exchange medium; k1 is the heat transfer coefficient of the evaporator; a1 is the heat transfer area of the evaporator; pe is the effective power output by the prime motor; phi 1 is the evaporation load; a condensing temperature tk ═ tw2+ ((1+ Pe/Φ 0)/((1-e ^ - α k) × Wm)) × Φ 2; wm qmw cw, α K2 a 2/Wm; wherein tw2 is ambient temperature; qmw is the mass flow of heat exchange medium; cw is the specific heat capacity of the heat exchange medium; k2 is the heat transfer coefficient of the condenser; a2 is the heat transfer area of the condenser; pe is the effective power output by the prime motor; φ 2 is the condensation load. The method can obtain a first threshold P1 of the pressure difference when the compressor generates surge or a second threshold P2 of the pressure difference when the compressor generates blockage and a mathematical model expression f (tk, t0) of the evaporation temperature and the condensation temperature when the unit operates under the specific working condition, for example, f (tk, t0) ═ c1+ c2 ^ t0+ c3 ^ tk + c4 ^ t0^2+ c5 ^ t0^ tk + c6 ^ tk ^2+ c7 ^ t0^3+ c8 ^ tk ^ t0^2+ c9 ^ t0^ tk ^2+ 686c 9 ^ t ^3, c 8656 is a constant, and the characteristic curves have different coefficients, so that the mathematical expressions can be obtained through experiments, and the specific expression coefficients are different from the compressor 8653 to obtain the characteristic curves. According to the formula, the controller of the unit can obtain the values of the parameters t0 and tk according to the inlet temperature and the ambient temperature of the heat exchange medium obtained by detection, and automatically calculate to obtain the second threshold value P2 of the differential pressure under the working condition of compressor blockage and the first threshold value P1 of the differential pressure under the surge working condition. The execution of step S2 is performed with an interval time of a first preset duration (e.g., 10min), and when the interval time is less than the first preset duration, the P1 and P2 obtained above are calculated.
S3, detecting the high pressure PH and the low pressure PH of the system, calculating to obtain a pressure difference value delta P of the compressor, judging the relation between the delta P and a second threshold value P2 and a first threshold value P1, and executing a step S4 if the delta P is more than or equal to P2 and less than or equal to P1; if Δ P < P2, perform step S5; if Δ P > P1, step S6 is performed.
The high pressure PH is detected by a pressure sensor on a line between the compressor and the condenser, and the low pressure PL is detected by a pressure sensor on a line between the compressor and the throttle valve.
And S4, controlling the opening degree of the throttle valve to be kept unchanged.
If the pressure P is more than or equal to P2 and less than or equal to P1, the current working condition is normal, no surge or blockage exists, and the opening of the throttle valve is controlled to be kept unchanged, so that the low-pressure is kept unchanged.
And S5, controlling the throttle opening to be reduced.
If the delta P is less than P2, the compressor is in a blockage condition, the opening degree of the throttle valve needs to be controlled to be reduced, and the opening degree reduction step number K1 is equal to the delta P-P2 multiplied by 0.05 multiplied by 100%.
And S6, controlling the throttle opening to increase.
If the delta P is more than P1, the compressor is in a surge condition, the opening of the throttle valve is required to be increased, and the opening increasing step number K2 is equal to the delta P-P1 multiplied by 0.05 multiplied by 100%.
After performing step S4, step S5, or step S6 for a second preset duration (e.g., 1min), the process returns to step S2.
The unit and the operation control method thereof overcome the problems of surge or blockage of the compressor in the air-cooled water chilling unit, and widen the operation range of the compressor, thereby improving the operation stability and reliability of the whole unit and enabling the unit to operate stably and efficiently under different operation conditions.
Example 6
The present embodiment provides a computer-readable storage medium on which a computer program is stored, which when executed by a processor implements the operation control method in the above-described embodiments.
The above-described embodiments of the assembly are merely illustrative, wherein the units described as separate parts may or may not be physically separate, and the parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment.
Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware. With this understanding in mind, the above-described technical solutions may be embodied in the form of a software product, which can be stored in a computer-readable storage medium such as ROM/RAM, magnetic disk, optical disk, etc., and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the methods described in the embodiments or some parts of the embodiments.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (13)
1. An assembly, wherein the assembly includes compressor, condenser, expansion valve and evaporimeter, its characterized in that, the assembly still includes:
the throttle valve is arranged on a pipeline between the evaporator and the compressor, and the opening degree of the throttle valve is used for controlling the low-pressure of the unit;
and the controller is connected with the throttle valve and is used for controlling the opening of the throttle valve according to the high-pressure and low-pressure of the unit so as to adjust the low-pressure.
2. The assembly according to claim 1, characterized in that said controller comprises:
a first control unit configured to control an opening degree of the throttle valve to increase the low pressure when a pressure difference between the high pressure and the low pressure is greater than a first threshold;
a second control unit configured to control the opening degree of the throttle valve to be kept constant so as to keep the low-pressure constant when the differential pressure is less than or equal to the first threshold and greater than or equal to a second threshold;
a third control unit configured to control an opening degree of the throttle valve to be decreased to lower the low pressure when the differential pressure is smaller than the second threshold value.
3. The assembly according to claim 2,
the unit further comprises: the first temperature sensor is arranged at the inlet end of the evaporator and used for detecting the inlet temperature of a heat exchange medium of the evaporator; the second temperature sensor is arranged in the environment and used for detecting the environment temperature;
the controller further includes: and the threshold setting unit is used for setting the first threshold and the second threshold according to the inlet temperature of the heat exchange medium, the ambient temperature and the characteristic curve of the compressor.
4. The aggregate according to claim 1, characterized in that it further comprises:
the first pressure sensor is arranged on a pipeline between the compressor and the condenser and used for detecting the high-pressure;
and the second pressure sensor is arranged on a pipeline between the throttling valve and the compressor and used for detecting the low-pressure.
5. The aggregate according to claim 1, characterized in that it further comprises:
the pressure balance pipeline is arranged between the exhaust end and the suction end of the compressor and connected with the condenser, the expansion valve and a branch formed by the evaporator in parallel, a pressure balance valve is arranged on the pressure balance pipeline, and the opening degree of the pressure balance valve is used for adjusting the pressure difference between the high pressure and the low pressure.
6. An operation control method applied to the unit according to any one of claims 1 to 5, characterized in that the method comprises:
acquiring high pressure and low pressure of a unit;
adjusting an opening degree of a throttle valve to adjust the low pressure according to a pressure difference between the high pressure and the low pressure; the throttling valve is arranged on a pipeline between an evaporator and a compressor of the unit.
7. The method of claim 6, wherein adjusting the low pressure based on a pressure differential between the high pressure and the low pressure comprises:
controlling an opening degree of a throttle valve to increase the low pressure if a pressure difference between the high pressure and the low pressure is greater than a first threshold;
if the differential pressure is less than or equal to the first threshold value and greater than or equal to a second threshold value, controlling the opening of the throttle valve to be kept unchanged so as to keep the low-pressure unchanged;
and if the differential pressure is smaller than the second threshold value, controlling the opening degree of the throttle valve to be reduced so as to reduce the low-pressure.
8. The method of claim 7, wherein prior to adjusting the low pressure based on the pressure differential between the high pressure and the low pressure, the method further comprises:
acquiring the inlet temperature and the ambient temperature of a heat exchange medium of an evaporator;
and determining the first threshold value and the second threshold value according to the inlet temperature of the heat exchange medium, the ambient temperature and the characteristic curve of the compressor.
9. The method of claim 8, wherein after determining the first threshold and the second threshold based on the inlet temperature of the heat exchange medium, the ambient temperature, and a characteristic curve of the compressor, the method further comprises:
and updating the first threshold value and the second threshold value according to the inlet temperature of the heat exchange medium, the ambient temperature and the characteristic curve of the compressor every first preset time interval.
10. The method of claim 6, wherein after adjusting the low pressure based on the pressure differential between the high pressure and the low pressure, the method further comprises:
and after a second preset time, triggering again to adjust the opening of the throttle valve according to the pressure difference between the high pressure and the low pressure so as to adjust the low pressure.
11. The method of claim 10, wherein before adjusting the opening of the throttle valve to adjust the low pressure based on a pressure difference between the high pressure and the low pressure, the method further comprises:
judging whether the throttle valve reaches the maximum opening or the minimum opening;
if yes, adjusting the opening degree of a pressure balance valve according to the pressure difference between the high pressure and the low pressure to adjust the pressure difference; the pressure balance valve is arranged on a pressure balance pipeline, and the pressure balance pipeline is arranged between the exhaust end and the suction end of the compressor.
12. The method of claim 11, wherein adjusting an opening of a pressure balancing valve to adjust the pressure differential based on the pressure differential of the high pressure and the low pressure comprises:
increasing the opening degree of the pressure balancing valve to reduce a differential pressure if the differential pressure between the high pressure and the low pressure is greater than a first threshold value;
if the pressure difference between the high pressure and the low pressure is less than a second threshold, the opening of the pressure balancing valve is decreased to increase the pressure difference.
13. A computer-readable storage medium, on which a computer program is stored, which program, when being executed by a processor, carries out the method according to any one of claims 6 to 12.
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| CN202011420322.3A CN112556220A (en) | 2020-12-07 | 2020-12-07 | Unit and operation control method thereof |
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| CN202011420322.3A CN112556220A (en) | 2020-12-07 | 2020-12-07 | Unit and operation control method thereof |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114216210A (en) * | 2021-12-20 | 2022-03-22 | 珠海格力电器股份有限公司 | Method for judging blocking condition of refrigeration system and air conditioner |
| CN114857760A (en) * | 2022-06-02 | 2022-08-05 | 青岛海信日立空调系统有限公司 | Air conditioning unit |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5355691A (en) * | 1993-08-16 | 1994-10-18 | American Standard Inc. | Control method and apparatus for a centrifugal chiller using a variable speed impeller motor drive |
| US5971712A (en) * | 1996-05-22 | 1999-10-26 | Ingersoll-Rand Company | Method for detecting the occurrence of surge in a centrifugal compressor |
| US20120048387A1 (en) * | 2010-08-31 | 2012-03-01 | Daniele Galeotti | Device and method for detecting a surge in a compressor and relocating a surge margin |
| CN203627330U (en) * | 2013-09-05 | 2014-06-04 | 广州恒星冷冻机械制造有限公司 | Anti-surge device of centrifugal compressor |
| CN104848587A (en) * | 2014-02-18 | 2015-08-19 | 青岛海信日立空调系统有限公司 | Frequency conversion multi-connected type heat pump system and control method of bypass electronic expansion valve |
| CN107763776A (en) * | 2017-11-20 | 2018-03-06 | 珠海格力电器股份有限公司 | Air-conditioner set and refrigerant migration control method |
| CN209801845U (en) * | 2019-04-03 | 2019-12-17 | 郑州凯雪运输制冷设备有限公司 | novel refrigerating unit pipeline structure |
| CN110878759A (en) * | 2018-09-06 | 2020-03-13 | 新特能源股份有限公司 | Anti-surge control method for high-rotation-speed centrifugal compressor |
-
2020
- 2020-12-07 CN CN202011420322.3A patent/CN112556220A/en active Pending
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5355691A (en) * | 1993-08-16 | 1994-10-18 | American Standard Inc. | Control method and apparatus for a centrifugal chiller using a variable speed impeller motor drive |
| US5971712A (en) * | 1996-05-22 | 1999-10-26 | Ingersoll-Rand Company | Method for detecting the occurrence of surge in a centrifugal compressor |
| US20120048387A1 (en) * | 2010-08-31 | 2012-03-01 | Daniele Galeotti | Device and method for detecting a surge in a compressor and relocating a surge margin |
| CN203627330U (en) * | 2013-09-05 | 2014-06-04 | 广州恒星冷冻机械制造有限公司 | Anti-surge device of centrifugal compressor |
| CN104848587A (en) * | 2014-02-18 | 2015-08-19 | 青岛海信日立空调系统有限公司 | Frequency conversion multi-connected type heat pump system and control method of bypass electronic expansion valve |
| CN107763776A (en) * | 2017-11-20 | 2018-03-06 | 珠海格力电器股份有限公司 | Air-conditioner set and refrigerant migration control method |
| CN110878759A (en) * | 2018-09-06 | 2020-03-13 | 新特能源股份有限公司 | Anti-surge control method for high-rotation-speed centrifugal compressor |
| CN209801845U (en) * | 2019-04-03 | 2019-12-17 | 郑州凯雪运输制冷设备有限公司 | novel refrigerating unit pipeline structure |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114216210A (en) * | 2021-12-20 | 2022-03-22 | 珠海格力电器股份有限公司 | Method for judging blocking condition of refrigeration system and air conditioner |
| CN114857760A (en) * | 2022-06-02 | 2022-08-05 | 青岛海信日立空调系统有限公司 | Air conditioning unit |
| CN114857760B (en) * | 2022-06-02 | 2023-09-26 | 青岛海信日立空调系统有限公司 | Air conditioning unit |
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Application publication date: 20210326 |