CN108800634B - Two-stage centrifugal water chilling unit and one-stage throttling control method and device thereof - Google Patents

Two-stage centrifugal water chilling unit and one-stage throttling control method and device thereof Download PDF

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Publication number
CN108800634B
CN108800634B CN201810713890.9A CN201810713890A CN108800634B CN 108800634 B CN108800634 B CN 108800634B CN 201810713890 A CN201810713890 A CN 201810713890A CN 108800634 B CN108800634 B CN 108800634B
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supercooling degree
current
load
target supercooling
condenser
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CN108800634A (en
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周登青
张运乾
王永
梁涛
钱小龙
李镇杉
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Midea Group Co Ltd
Chongqing Midea General Refrigeration Equipment Co Ltd
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Midea Group Co Ltd
Chongqing Midea General Refrigeration Equipment Co Ltd
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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
    • 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
    • F25B41/00—Fluid-circulation arrangements
    • F25B41/30—Expansion means; Dispositions thereof
    • 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
    • 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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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Air Conditioning Control Device (AREA)

Abstract

The invention discloses a two-stage centrifugal water chilling unit and a control method and device for one-stage throttling of the two-stage centrifugal water chilling unit. The control method comprises the following steps: adjusting the current target supercooling degree of the condenser according to the load change of the water chilling unit; and adjusting the primary throttle valve according to the current target supercooling degree. The two-stage centrifugal water chilling unit and the control method and device of the one-stage throttling valve thereof realize dynamic adjustment of the one-stage throttling valve according to the change of the load, thereby improving the energy efficiency of the water chilling unit under partial load.

Description

Two-stage centrifugal water chilling unit and one-stage throttling control method and device thereof
Technical Field
The invention relates to the technical field of air conditioners, in particular to a two-stage centrifugal water chilling unit and a control method and device of one-stage throttling of the two-stage centrifugal water chilling unit.
Background
Two-stage centrifugal compressors are widely used in centrifugal chiller units. Generally, for a two-stage centrifugal chiller, the first-stage throttling has a large influence on the energy efficiency, and in order to improve the whole-time operation energy efficiency of the chiller, the conventional method is to perform first-stage auxiliary adjustment on a centrifugal chiller with small energy by generally adopting an electronic expansion valve or an analog quantity electric butterfly valve, so as to adjust the refrigerant flow and further realize load adjustment, wherein the control parameter of the conventional method is the evaporator liquid level or the suction superheat degree.
However, in the above-mentioned one-stage throttling control mode, under the working conditions of partial load, especially under the working conditions of large pressure ratio and small flow, the liquid level at the condenser side is easy to decrease, so that part of high-pressure gas enters the economizer through the throttling orifice plate or the electronic expansion valve, thereby reducing the energy efficiency of the water chilling unit.
Disclosure of Invention
The present invention is directed to solving, at least to some extent, one of the technical problems in the related art.
Therefore, the first object of the present invention is to provide a two-stage centrifugal chiller and a control method of one-stage throttling thereof, so as to dynamically change the target supercooling degree according to the change of the load, thereby realizing the adjustment of the one-stage throttling valve and improving the energy efficiency of the chiller under partial load.
The second purpose of the invention is to provide a control device for the primary throttling of the double-stage centrifugal water chilling unit.
The third purpose of the invention is to provide a two-stage centrifugal water chilling unit
A fourth object of the invention is to propose an electronic device.
A fifth object of the invention is to propose a non-transitory computer-readable storage medium.
In order to achieve the above object, a first aspect of the present invention provides a method for controlling a first-stage throttling of a two-stage centrifugal chiller, including: adjusting the current target supercooling degree of the condenser according to the load change of the water chilling unit; and adjusting the primary throttle valve according to the current target supercooling degree.
The control method for the primary throttling of the two-stage centrifugal chiller unit can dynamically adjust the current target supercooling degree of the condenser according to the load change of the chiller unit, and adjust the primary throttling valve according to the current target supercooling degree, so that the primary throttling valve is dynamically adjusted according to the load change, and the energy efficiency of the chiller unit under partial load is improved.
In order to achieve the above object, a second aspect of the present invention provides a control device for one-stage throttling of a two-stage centrifugal chiller, including: the adjusting module is used for adjusting the current target supercooling degree of the condenser according to the load change of the water chilling unit; and the adjusting module is used for adjusting the primary throttle valve according to the current target supercooling degree.
The control device for the primary throttling of the two-stage centrifugal chiller can dynamically adjust the current target supercooling degree of the condenser according to the load change of the chiller and adjust the primary throttling valve according to the current target supercooling degree, so that the primary throttling valve is dynamically adjusted according to the load change, and the energy efficiency of the chiller under partial load is improved even under the working condition of small pressurizing ratio flow.
In order to achieve the above object, a third aspect of the present invention provides a two-stage centrifugal chiller, including: the control device for the one-stage throttling of the two-stage centrifugal water chilling unit according to the embodiment of the second aspect of the invention.
The two-stage centrifugal chiller unit provided by the embodiment of the invention can dynamically adjust the current target supercooling degree of the condenser according to the load change of the chiller unit, and adjust the first-stage throttle valve according to the current target supercooling degree, so that the dynamic adjustment of the first-stage throttle valve according to the load change is realized, and the energy efficiency of the chiller unit under partial load is improved.
To achieve the above object, a fourth aspect of the present invention provides an electronic device, including: the control method comprises the steps of storing a first-stage throttling value in a storage device, storing a second-stage throttling value in the storage device, and executing a first-stage throttling value by using a first-stage throttling value storage device.
To achieve the above object, a fifth embodiment of the present invention provides a non-transitory computer-readable storage medium, on which a computer program is stored, the computer program being executed by a processor to implement a control method for one-stage throttling of a dual-stage centrifugal chiller according to the first embodiment of the present invention.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Drawings
FIG. 1 is a flow chart of a control method for one-stage throttling of a two-stage centrifugal chiller according to one embodiment of the invention;
FIG. 2 is a flow chart of a control method for the one-stage throttling of a dual-stage centrifugal chiller according to another embodiment of the present invention;
fig. 3 is a block diagram of a control device for the one-stage throttling of a two-stage centrifugal chiller according to an embodiment of the present invention.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.
The following describes a two-stage centrifugal chiller and a method and device for controlling one-stage throttling thereof according to an embodiment of the present invention with reference to the accompanying drawings.
Fig. 1 is a flow chart of a control method for one-stage throttling of a two-stage centrifugal chiller according to an embodiment of the invention.
As shown in fig. 1, a method for controlling a first-stage throttle of a two-stage centrifugal chiller according to an embodiment of the present invention includes the following steps:
and S101, adjusting the current target supercooling degree of the condenser according to the load change of the water chilling unit.
Specifically, the load of the water chilling unit is detected in real time, and the current target supercooling degree delta T of the condenser is dynamically adjusted according to the change of the load.
And S102, adjusting the primary throttle valve according to the current target supercooling degree.
Specifically, the opening degree of the primary throttle valve is adjusted by taking the current target supercooling degree delta T as a target parameter, so that the opening degree of the primary throttle valve is dynamically adjusted according to the change of the load, and the situation that the pressure of an economizer is too small and the energy efficiency of a water chilling unit is reduced due to the fact that the opening degree of the primary throttle valve is too small when part of the load is avoided.
At the current load, the current supercooling degree of the condenser is Tsat-Tc, Tsat is the current saturation temperature of the condenser, Tc is the current liquid outlet temperature of the condenser, and the condenser can realize the current theoretical maximum supercooling degree (delta T) max which is Tsat-Tci because a certain temperature difference is needed for heat transfer. When the water inlet temperature of the condenser is not changed, the current saturation temperature Tsat of the condenser is reduced along with the reduction of the load, and the current theoretical maximum supercooling degree (delta T) max is inevitably reduced, so the current target supercooling degree should be correspondingly reduced, otherwise, under a small-load working condition, the situation that the current supercooling degree still does not reach the current target supercooling degree due to the fact that the first-stage throttle valve is completely closed may occur, and worse, the pressure of the economizer is smaller due to the fact that the first-stage throttle valve is excessively closed, and therefore the energy efficiency of the water chilling unit is reduced. Therefore, the embodiment of the invention dynamically adjusts the opening of the primary throttle valve according to the change of the load, and avoids the problems that the pressure of an economizer is too low and the energy efficiency of a water chilling unit is reduced because the opening of the primary throttle valve is too small when the load is partially loaded.
The control method for the primary throttling of the two-stage centrifugal chiller unit can dynamically adjust the current target supercooling degree of the condenser according to the load change of the chiller unit, and adjust the primary throttling valve according to the current target supercooling degree, so that the primary throttling valve is dynamically adjusted according to the load change, and the energy efficiency of the chiller unit under partial load is improved.
Fig. 2 is a flow chart of a control method for one-stage throttling of a two-stage centrifugal chiller according to another embodiment of the invention. The method for controlling the primary throttling of the two-stage centrifugal chiller unit in the embodiment of the invention is a specific implementation manner of the method for controlling the primary throttling of the two-stage centrifugal chiller unit shown in fig. 1. As shown in fig. 2, the method for controlling the one-stage throttling of the two-stage centrifugal chiller according to the embodiment of the present invention includes:
on the basis of the embodiment shown in fig. 1, as a first possible implementation, step S101 specifically includes the following steps S201 to S202.
S201, calculating the difference value between the current saturation temperature and the current inlet water temperature of the condenser to obtain the current theoretical maximum supercooling degree of the condenser at the current load.
In particular, when calculating the current load, condensation takes placeThe difference value of the current saturation temperature Tsat and the current inlet water temperature Tci of the condenser obtains the current theoretical maximum supercooling degree (delta T) of the condenser at the current loadmax＝Tsat-Tci。
S202, calculating to obtain the current target supercooling degree of the condenser at the current load according to the current theoretical maximum supercooling degree and the full load target supercooling degree of the condenser at the full load.
In particular, according to the current theory maximum supercooling degree (Δ T)maxAnd a full load target subcooling degree Δ T0 (which is a known quantity) of the condenser at full load (i.e., 100% load), and calculating to obtain a current target subcooling degree Δ T ═ Δ T0(Δ T) of the condenser at current loadmaxAnd ξ. Where ξ is a constant associated with the condenser.
Further, step S202 may specifically include: calculating the difference value between the full-load saturation temperature of the condenser and the full-load inlet water temperature at full load to obtain the full-load theoretical maximum supercooling degree of the condenser at full load; calculating the ratio of the current theoretical maximum supercooling degree to the full load theoretical maximum supercooling degree to obtain a first load percentage; and calculating the product of the first load percentage and the full-load target supercooling degree to obtain the current target supercooling degree.
Specifically, the difference between the full load saturation temperature Tsat0 of the condenser and the full load inlet water temperature Tci0 at full load is calculated to obtain the full load theoretical maximum supercooling degree (delta T0) of the condenser at full loadmaxTsat0-Tci 0. Calculating the theoretical maximum supercooling degree (Delta T)maxTheoretical maximum supercooling degree at full load (delta T0)maxTo obtain the first load percentage z1 ═ Tmax/(ΔT0)max. Calculating the product of the first load percentage z 1% and the full load target supercooling degree delta T0 (which is a known quantity), and obtaining the current target supercooling degree delta T0 z 1% delta T0 (delta T)max/(ΔT0)max＝ΔT0*(ΔT)max/(Tsat0-Tci 0). Namely xi is taken as the maximum supercooling degree (delta T0) of the full load theorymax＝Tsat0-Tci0。
On the basis of the embodiment shown in fig. 1, as a second possible implementation, the step S101 specifically includes the following steps: calculating the difference value between the current water outlet temperature and the current water inlet temperature of the condenser to obtain the current water inlet and outlet temperature difference of the condenser at the current load; calculating the difference value between the full-load water outlet temperature and the full-load water inlet temperature of the condenser under the rated design working condition to obtain the rated water inlet and outlet temperature difference of the condenser under the rated design working condition; calculating the ratio of the current water inlet and outlet temperature difference to the rated water inlet and outlet temperature difference to obtain a second load percentage; and calculating the product of the second load percentage and the full-load target supercooling degree of the condenser at full load to obtain the current target supercooling degree.
Specifically, when the current load is calculated, the difference between the current outlet water temperature Tco and the current inlet water temperature Tci of the condenser is obtained to obtain the current inlet and outlet water temperature difference Δ T of the condenser when the load is currentCurrent temperature differenceTco-Tci. Calculating the difference between the full-load outlet water temperature Tco0 and the full-load inlet water temperature Tci0 of the condenser under the rated design working condition to obtain the rated inlet and outlet water temperature difference delta T of the condenser under the rated design working conditionRated temperature differenceTco0-Tci 0. Calculating the current inlet and outlet water temperature difference delta TCurrent temperature differenceAnd rated water inlet and outlet temperature difference delta TRated temperature differenceTo obtain a second load percentage z 1%Current temperature difference/ΔTRated temperature difference(ii) a And calculating the product of the second load percentage z 1% and the full load target supercooling degree delta T0 (which is a known quantity) of the condenser at the full load to obtain the current target supercooling degree delta T which is delta T0 and z2 and is delta T0 and delta TCurrent temperature difference/ΔTRated temperature difference＝ΔT0*(Tco-Tci)/(Tco0-Tci0)。
On the basis of the embodiment shown in fig. 1, step S102 specifically includes the following steps: S203-S204.
And S203, correcting the current target supercooling degree according to the current operating pressure ratio of the water chilling unit.
Specifically, when the operating pressure ratio of the unit changes, the target supercooling degree Δ T obtained according to the scheme is basically the same for the high-pressure-ratio full load and the low-pressure-ratio full load, but under the condition of the low pressure ratio, the pressure difference between the front and the rear of the primary throttle valve is reduced, under the condition of ensuring the same supercooling degree, the flow rate of the refrigerant under the working condition of the low pressure ratio is reduced sharply, and at this time, the supercooling degree meets the control requirement, but the condition of liquid shortage occurs in a lower-level container (an economizer) may occur. Therefore, it is necessary to introduce the current operation pressure ratio of the system to correct the current target supercooling degree delta T obtained by the scheme. The current operating pressure ratio is equal to the current saturation pressure Pc, sat of the condenser and the current saturation pressure Pe, sat of the evaporator, and the ratio of Pc, sat/Pe, sat.
The correction function may be expressed as f (), and simply may be taken as f () ═ a + b, where 0 ≦ a ≦ 1 coefficient and b is a constant. When a is 0 and b is 1, the scheme degenerates to the scheme before the correction. Corrected current target supercooling degree delta TCorrection＝f()*ΔT＝(a+b)*ΔT。
And S204, adjusting the primary throttle valve according to the corrected current target supercooling degree.
Specifically, the corrected current target supercooling degree delta TCorrectionThe opening of the primary throttle valve is adjusted for a target parameter, so that the opening of the primary throttle valve is dynamically adjusted according to the change of the load, and the problems that the pressure of an economizer is too low and the energy efficiency of a water chilling unit is reduced due to the fact that the opening of the primary throttle valve is too small when the load is partially loaded are avoided.
Further, step S203 may specifically include: calculating the ratio of the current operating pressure ratio to the rated operating pressure ratio to obtain a correction coefficient; and calculating the product of the correction coefficient and the current target supercooling degree to obtain the corrected current target supercooling degree.
Specifically, the ratio of the current operating pressure ratio to the rated operating pressure ratio 0 is calculated to obtain the correction coefficient c. Calculating the product of the correction coefficient c and the current target supercooling degree delta T to obtain the corrected current target supercooling degree delta TCorrectionAnd c, delta T/0. I.e. a is 1/0 and b is 0.
For the purpose of clearly explaining the calculation process and the correction process of the target supercooling degree Δ T, the following description will be made by way of example.
The rated design working condition of a certain water chilling unit is known to be 7/30, namely the full-load outlet water temperature of an evaporator is 7 ℃, the full-load inlet water temperature Tci0 of a condenser is 30 ℃, the inlet and outlet water temperatures of the evaporator and the condenser are both 5 ℃, the full-load saturation temperature Tsat0 of the condenser is 36 ℃, and the full-load target supercooling degree delta T0 at full load is 3 ℃. ξ ═ (Tsat0-Tci0) ═ 36 ℃ -30 ℃ and 6 ℃.
The first embodiment is as follows:
assuming that the water chilling unit currently operates under a rated design condition 7/30, that is, the current outlet water temperature of the evaporator is 7 ℃, the current inlet water temperature Tci of the condenser is 30 ℃, the load is 50%, and the current saturation temperature Tsat of the condenser is 33 ℃, the current target supercooling degree Δ T ═ Δ T0 ═ Tsat-Tci)/ξ ═ 3 × (33-30)/6 ═ 1.5 ℃ is calculated.
Example two:
assuming that the unit currently operates under the 7/24 working condition, that is, the current outlet water temperature of the evaporator is 7 ℃, the current inlet water temperature Tci of the condenser is 24 ℃, the load is 50%, and the current saturation temperature Tsat of the condenser is 27 ℃, then the current target supercooling degree Δ T ═ Δ T0 ═ Tsat-Tci)/ξ ═ 3 × (33-30)/6 ═ 1.5 ℃ is calculated.
And after the target supercooling degree delta T is obtained, introducing the current operating pressure ratio to correct the current target supercooling degree delta T. Assuming that the current saturation temperature of the evaporator is 6 ℃, the corresponding current saturation pressure is 362 kPa; the current saturation temperature Tsat of the condenser is 27 ℃, and the corresponding current saturation pressure is 706kPa, so that the current operating pressure ratio is 706/362-1.95. If 0 is 2.55 (i.e., the rated operating pressure ratio of the water chilling unit at full load under the condition of 7/30), b is 0, i.e., f () '1/2.55, and f ()' 0.765 is obtained by calculation, the corrected target supercooling degree delta T at this time is obtainedCorrection＝0.765*1.5＝1.1475℃。
Furthermore, in the implementation process, in order to prevent the influence of the sensor precision on the target supercooling degree, the target supercooling degree should be limited by a minimum value and a maximum value, namely, if the target supercooling degree (or the corrected target supercooling degree) calculated by the scheme is smaller than the minimum value, the minimum value is taken; when the calculated target supercooling degree (or the corrected target supercooling degree) is greater than the maximum value, the maximum value is taken. Taking a scheme of not correcting the target supercooling degree as an example, step S102 in the embodiment shown in fig. 1 specifically includes the following steps:
if the current target supercooling degree is smaller than a preset minimum target supercooling degree threshold value, adjusting the primary throttle valve according to the minimum target supercooling degree threshold value; if the current target supercooling degree is larger than a preset maximum target supercooling degree threshold value, adjusting the primary throttle valve according to the maximum target supercooling degree threshold value; and if the current target supercooling degree is equal to or larger than the minimum target supercooling degree threshold value and is equal to or smaller than the maximum target supercooling degree threshold value, adjusting the primary throttle valve according to the current target supercooling degree.
The control method for the primary throttling of the two-stage centrifugal chiller unit can dynamically adjust the current target supercooling degree of the condenser according to the load change of the chiller unit, and adjust the primary throttling valve according to the current target supercooling degree, so that the primary throttling valve is dynamically adjusted according to the load change, and the energy efficiency of the chiller unit under partial load is improved.
In order to realize the embodiment, the invention also provides a control device for the primary throttling of the two-stage centrifugal water chilling unit. Fig. 3 is a block diagram of a control device for one-stage throttling of a dual-stage centrifugal chiller according to an embodiment of the present invention, and as shown in fig. 3, the control device for one-stage throttling of a dual-stage centrifugal chiller according to an embodiment of the present invention includes: an adjustment module 10 and a regulation module 11.
And the adjusting module 10 is used for adjusting the current target supercooling degree of the condenser according to the load change of the water chilling unit.
And the adjusting module 11 is used for adjusting the primary throttle valve according to the current target supercooling degree.
Further, in a possible implementation manner of the embodiment of the present invention, the adjusting module 10 includes: the first calculating unit is used for calculating the difference value between the current saturation temperature and the current inlet water temperature of the condenser to obtain the current theoretical maximum supercooling degree of the condenser at the current load; and the second calculating unit is used for calculating and obtaining the current target supercooling degree of the condenser at the current load according to the current theoretical maximum supercooling degree and the full load target supercooling degree of the condenser at the full load.
Further, in a possible implementation manner of the embodiment of the present invention, the second calculating unit is specifically configured to: calculating the difference value between the full-load saturation temperature of the condenser and the full-load inlet water temperature at full load to obtain the full-load theoretical maximum supercooling degree of the condenser at full load; calculating the ratio of the current theoretical maximum supercooling degree to the full load theoretical maximum supercooling degree to obtain a first load percentage; and calculating the product of the first load percentage and the full-load target supercooling degree to obtain the current target supercooling degree.
Further, in a possible implementation manner of the embodiment of the present invention, the adjusting module 10 is specifically configured to: calculating the difference value between the current water outlet temperature and the current water inlet temperature of the condenser to obtain the current water inlet and outlet temperature difference of the condenser at the current load; calculating the difference value between the full-load water outlet temperature and the full-load water inlet temperature of the condenser under the rated design working condition to obtain the rated water inlet and outlet temperature difference of the condenser under the rated design working condition; calculating the ratio of the current water inlet and outlet temperature difference to the rated water inlet and outlet temperature difference to obtain a second load percentage; and calculating the product of the second load percentage and the full-load target supercooling degree of the condenser at full load to obtain the current target supercooling degree.
Further, in a possible implementation manner of the embodiment of the present invention, the adjusting module 11 includes: a correction unit and an adjustment unit. The correction unit is used for correcting the current target supercooling degree according to the current operating pressure ratio of the water chilling unit; and the adjusting unit is used for adjusting the primary throttle valve according to the corrected current target supercooling degree.
Further, in a possible implementation manner of the embodiment of the present invention, the modification unit is specifically configured to: calculating the ratio of the current operating pressure ratio to the rated operating pressure ratio to obtain a correction coefficient; and calculating the product of the correction coefficient and the current target supercooling degree to obtain the corrected current target supercooling degree.
Further, in a possible implementation manner of the embodiment of the present invention, the adjusting module 11 is specifically configured to: if the current target supercooling degree is smaller than a preset minimum target supercooling degree threshold value, adjusting the primary throttle valve according to the minimum target supercooling degree threshold value; if the current target supercooling degree is larger than a preset maximum target supercooling degree threshold value, adjusting the primary throttle valve according to the maximum target supercooling degree threshold value; and if the current target supercooling degree is equal to or larger than the minimum target supercooling degree threshold value and is equal to or smaller than the maximum target supercooling degree threshold value, adjusting the primary throttle valve according to the current target supercooling degree.
It should be noted that the explanation of the embodiment of the control method for the first-stage throttling of the dual-stage centrifugal chiller unit is also applicable to the control device for the first-stage throttling of the dual-stage centrifugal chiller unit of the embodiment, and details are not repeated here.
The control device for the primary throttling of the two-stage centrifugal chiller can dynamically adjust the current target supercooling degree of the condenser according to the load change of the chiller, and adjust the primary throttling valve according to the current target supercooling degree, so that the primary throttling valve is dynamically adjusted according to the load change, and the energy efficiency of the chiller under partial load is improved.
In order to implement the above embodiment, an embodiment of the present invention further provides a dual-stage centrifugal chiller, which includes the control device for controlling the primary throttling of the dual-stage centrifugal chiller shown in the above embodiment.
In order to implement the above embodiments, an electronic device according to an embodiment of the present invention is further provided, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor, where the processor executes the computer program to implement the control method for controlling the one-stage throttling of the dual-stage centrifugal chiller according to the above embodiments.
In order to implement the above embodiments, the embodiment of the present invention further proposes a non-transitory computer-readable storage medium, on which a computer program is stored, the computer program being executed by a processor for implementing the control method for the one-stage throttling of the dual-stage centrifugal chiller according to the above embodiments.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.

Claims (11)

1. A control method for one-stage throttling of a two-stage centrifugal water chilling unit is characterized by comprising the following steps:
adjusting the current target supercooling degree of the condenser according to the load change of the water chilling unit;
adjusting the primary throttle valve according to the current target supercooling degree;
the current target supercooling degree of the condenser is adjusted according to the load change of the water chilling unit, and the method comprises the following steps:
calculating the difference value between the current saturation temperature and the current inlet water temperature of the condenser to obtain the current theoretical maximum supercooling degree of the condenser at the current load;
calculating to obtain the current target supercooling degree of the condenser at the current load according to the current theoretical maximum supercooling degree and the full load target supercooling degree of the condenser at the full load;
the adjusting of the primary throttle valve according to the current target supercooling degree comprises the following steps:
correcting the current target supercooling degree according to the current operating pressure ratio of the water chilling unit;
and adjusting the primary throttle valve according to the corrected current target supercooling degree.
2. The control method of claim 1, wherein calculating the current target subcooling degree for a condenser at current load from the current theoretical maximum subcooling degree and a full load target subcooling degree for the condenser at full load comprises:
calculating the difference value between the full-load saturation temperature of the condenser and the full-load inlet water temperature at full load to obtain the full-load theoretical maximum supercooling degree of the condenser at full load;
calculating the ratio of the current theoretical maximum supercooling degree to the full-load theoretical maximum supercooling degree to obtain a first load percentage;
and calculating the product of the first load percentage and the full-load target supercooling degree to obtain the current target supercooling degree.
3. The control method according to claim 1, wherein the correcting the current target supercooling degree according to the current operating pressure ratio of the water chilling unit comprises:
calculating the ratio of the current operating pressure ratio to the rated operating pressure ratio to obtain a correction coefficient;
and calculating the product of the correction coefficient and the current target supercooling degree to obtain the corrected current target supercooling degree.
4. The control method of claim 1, wherein said adjusting a primary throttle valve based on said current target subcooling comprises:
if the current target supercooling degree is smaller than a preset minimum target supercooling degree threshold value, adjusting the primary throttle valve according to the minimum target supercooling degree threshold value;
if the current target supercooling degree is larger than a preset maximum target supercooling degree threshold value, adjusting the primary throttle valve according to the maximum target supercooling degree threshold value;
and if the current target supercooling degree is equal to or larger than the minimum target supercooling degree threshold value and is equal to or smaller than the maximum target supercooling degree threshold value, adjusting the primary throttle valve according to the current target supercooling degree.
5. The utility model provides a controlling means of doublestage centrifugal chiller one-level throttle which characterized in that includes:
the adjusting module is used for adjusting the current target supercooling degree of the condenser according to the load change of the water chilling unit;
the adjusting module is used for adjusting the primary throttle valve according to the current target supercooling degree;
the adjustment module includes:
the first calculating unit is used for calculating the difference value between the current saturation temperature and the current inlet water temperature of the condenser to obtain the current theoretical maximum supercooling degree of the condenser at the current load;
the second calculation unit is used for calculating the current target supercooling degree of the condenser at the current load according to the current theoretical maximum supercooling degree and the full load target supercooling degree of the condenser at the full load;
the adjustment module includes:
the correction unit is used for correcting the current target supercooling degree according to the current operating pressure ratio of the water chilling unit;
and the adjusting unit is used for adjusting the primary throttle valve according to the corrected current target supercooling degree.
6. The control device according to claim 5, wherein the second calculation unit is specifically configured to:
calculating the difference value between the full-load saturation temperature of the condenser and the full-load inlet water temperature at full load to obtain the full-load theoretical maximum supercooling degree of the condenser at full load;
calculating the ratio of the current theoretical maximum supercooling degree to the full-load theoretical maximum supercooling degree to obtain a first load percentage;
and calculating the product of the first load percentage and the full-load target supercooling degree to obtain the current target supercooling degree.
7. The control device according to claim 5, wherein the correction unit is specifically configured to:
calculating the ratio of the current operating pressure ratio to the rated operating pressure ratio to obtain a correction coefficient;
and calculating the product of the correction coefficient and the current target supercooling degree to obtain the corrected current target supercooling degree.
8. The control device according to claim 5, wherein the adjustment module is specifically configured to:
if the current target supercooling degree is smaller than a preset minimum target supercooling degree threshold value, adjusting the primary throttle valve according to the minimum target supercooling degree threshold value;
if the current target supercooling degree is larger than a preset maximum target supercooling degree threshold value, adjusting the primary throttle valve according to the maximum target supercooling degree threshold value;
and if the current target supercooling degree is equal to or larger than the minimum target supercooling degree threshold value and is equal to or smaller than the maximum target supercooling degree threshold value, adjusting the primary throttle valve according to the current target supercooling degree.
9. A dual stage centrifugal chiller comprising: the control device for the primary throttle of the double-stage centrifugal water chilling unit according to any one of claims 5-8.
10. An electronic device, comprising: a memory, a processor and a computer program stored on the memory and executable on the processor, the processor executing the program to implement the control method for one-stage throttling of a dual-stage centrifugal chiller according to any one of claims 1-4.
11. A non-transitory computer readable storage medium having stored thereon a computer program, wherein the program is executed by a processor for implementing the control method for one-stage throttling of a dual-stage centrifugal chiller according to any one of claims 1-4.
CN201810713890.9A 2018-06-29 2018-06-29 Two-stage centrifugal water chilling unit and one-stage throttling control method and device thereof Active CN108800634B (en)

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CN110360780B (en) * 2019-07-23 2020-11-24 珠海格力电器股份有限公司 Multi-split air conditioning system, supercooling degree determination method, device and equipment thereof and storage medium
CN113075259B (en) * 2021-03-24 2024-07-09 新奥数能科技有限公司 Method and device for monitoring condensation approaching temperature of electric refrigerator in real time

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