CN117628756A

CN117628756A - Method and device for controlling water chilling unit, water chilling unit and storage medium

Info

Publication number: CN117628756A
Application number: CN202210994922.3A
Authority: CN
Inventors: 张辉; 邓善营; 张捷; 顾超; 王铁伟
Original assignee: Qingdao Haier Air Conditioner Gen Corp Ltd; Qingdao Haier Air Conditioning Electric Co Ltd; Haier Smart Home Co Ltd
Current assignee: Qingdao Haier Air Conditioner Gen Corp Ltd; Qingdao Haier Air Conditioning Electric Co Ltd; Haier Smart Home Co Ltd
Priority date: 2022-08-18
Filing date: 2022-08-18
Publication date: 2024-03-01

Abstract

The application relates to the technical field of air conditioners and discloses a method for controlling a water chilling unit, which comprises the following steps: under the condition that the water chilling unit is continuously unloaded with the cold load, obtaining the outlet water temperature of chilled water; calculating a difference value between the outlet water temperature of the chilled water and a preset shutdown temperature, and judging whether the difference value is smaller than a preset threshold value or not; and if the difference value is smaller than a preset threshold value, correcting the preset shutdown temperature to prolong the running time of the water chilling unit. When the load of the water chilling unit is continuously reduced and the difference between the chilled water outlet temperature and the preset shutdown temperature is smaller than a preset threshold value, the preset shutdown temperature is corrected. So as to prolong the running time of the water chilling unit and avoid misjudgment of shutdown. The start-stop times of the unit are reduced, and the energy efficiency of the system is improved. The application also discloses a device for controlling the water chilling unit, the water chilling unit and a storage medium.

Description

Method and device for controlling water chilling unit, water chilling unit and storage medium

Technical Field

The present application relates to the field of air conditioning technologies, and for example, to a method and an apparatus for controlling a water chiller, and a storage medium.

Background

The water chiller comprises a refrigerant system, a cooling water system and a chilled water system. During refrigeration, the compressor of the refrigerant system drives the refrigerant to circulate between the condenser and the evaporator. The cooling water in the cooling water system takes the heat generated by the condenser away to the cooling tower, and the chilled water in the chilled water system circulates the cold generated by the evaporator into the room, so that the indoor refrigeration is realized. When the indoor cooling load demand is rapidly reduced or kept low for a long time, the water chilling unit can be stopped, started and periodically started and shut down erroneously due to the limitation of the unloading speed and the minimum unloading capacity. Frequent start-stop of the unit causes great damage to the compressor.

In the related art, determining the current load of an air conditioning system according to the load rate of each water chilling unit in the air conditioning system when the load of the air conditioning system is maximum and the rated load of each water chilling unit; determining and setting the chilled water outlet temperature according to the maximum load, the current load and the load lower limit value; and controlling each water chilling unit according to the set chilled water outlet temperature.

In the process of implementing the embodiments of the present disclosure, it is found that at least the following problems exist in the related art:

only how to raise the chilled water outlet temperature under low load is disclosed in the related art. It is not disclosed how to solve the problems of erroneous judgment of machine set shutdown and frequent start-up and shutdown under low load.

Disclosure of Invention

The following presents a simplified summary in order to provide a basic understanding of some aspects of the disclosed embodiments. This summary is not an extensive overview, and is intended to neither identify key/critical elements nor delineate the scope of such embodiments, but is intended as a prelude to the more detailed description that follows.

The embodiment of the disclosure provides a method, a device, a water chilling unit and a storage medium for controlling the water chilling unit, so as to avoid misjudgment of shutdown, reduce the start-stop times of the unit and further improve the energy efficiency of a system.

In some embodiments, the method comprises: under the condition that the water chilling unit is continuously unloaded with the cold load, obtaining the outlet water temperature of chilled water; calculating a difference value between the outlet water temperature of the chilled water and a preset shutdown temperature, and judging whether the difference value is smaller than a preset threshold value or not; and if the difference value is smaller than a preset threshold value, correcting the preset shutdown temperature to prolong the running time of the water chilling unit.

In some embodiments, the apparatus comprises: a processor and a memory storing program instructions configured to perform the method for controlling a chiller as described above when the program instructions are executed.

In some embodiments, the control chiller includes: the device for controlling the water chiller is as described above.

In some embodiments, the storage medium stores program instructions that, when executed, perform a method for controlling a chiller as previously described.

The method, the device, the water chilling unit and the storage medium for controlling the water chilling unit provided by the embodiment of the disclosure can realize the following technical effects:

in the embodiment of the disclosure, when the load of the water chilling unit is continuously reduced, whether the difference value between the chilled water outlet temperature and the preset shutdown temperature is smaller than a preset threshold value is judged. If it is smaller, it indicates that the chilled water temperature changes faster. When the water temperature change time is faster than the unloading time of the water chilling unit, the water chilling unit can be stopped by misjudgment. And restarting after the water temperature rises, so that periodic start and stop are repeatedly formed. To avoid this, the preset shutdown temperature is corrected when the above condition is satisfied. So as to prolong the running time of the water chilling unit and avoid misjudgment of shutdown. The start-stop times of the unit are reduced, and the energy efficiency of the system is improved.

The foregoing general description and the following description are exemplary and explanatory only and are not restrictive of the application.

Drawings

One or more embodiments are illustrated by way of example and not limitation in the figures of the accompanying drawings, in which like references indicate similar elements, and in which like reference numerals refer to similar elements, and in which:

FIG. 1 is a schematic diagram of a method for controlling a chiller according to an embodiment of the present disclosure;

FIG. 2 is a schematic illustration of another method for controlling a chiller provided by an embodiment of the present disclosure;

FIG. 3 is a schematic illustration of another method for controlling a chiller provided by an embodiment of the present disclosure;

FIG. 4 is a schematic illustration of another method for controlling a chiller provided by an embodiment of the present disclosure;

FIG. 5 is a schematic diagram of an apparatus for controlling a chiller according to an embodiment of the present disclosure;

fig. 6 is a schematic diagram of another apparatus for controlling a chiller according to an embodiment of the present disclosure.

Detailed Description

So that the manner in which the features and techniques of the disclosed embodiments can be understood in more detail, a more particular description of the embodiments of the disclosure, briefly summarized below, may be had by reference to the appended drawings, which are not intended to be limiting of the embodiments of the disclosure. In the following description of the technology, for purposes of explanation, numerous details are set forth in order to provide a thorough understanding of the disclosed embodiments. However, one or more embodiments may still be practiced without these details. In other instances, well-known structures and devices may be shown simplified in order to simplify the drawing.

The terms first, second and the like in the description and in the claims of the embodiments of the disclosure and in the above-described figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate in order to describe embodiments of the present disclosure. Furthermore, the terms "comprise" and "have," as well as any variations thereof, are intended to cover a non-exclusive inclusion.

The term "plurality" means two or more, unless otherwise indicated.

In the embodiment of the present disclosure, the character "/" indicates that the front and rear objects are an or relationship. For example, A/B represents: a or B.

The term "and/or" is an associative relationship that describes an object, meaning that there may be three relationships. For example, a and/or B, represent: a or B, or, A and B.

The term "corresponding" may refer to an association or binding relationship, and the correspondence between a and B refers to an association or binding relationship between a and B.

At present, the refrigerating of the water chilling unit is controlled by parameters according to indoor cold load demand. When the indoor demand quantity changes and is larger than the current refrigerating capacity of the unit, the unit loads the load so as to maintain the water outlet temperature of the chilled water system at the set water outlet temperature. When the indoor demand quantity changes and is smaller than the current refrigerating capacity of the unit, the unit carries out load relief so as to maintain the chilled water outlet temperature at the set outlet temperature.

However, when the indoor cooling load demand changes and the demand is smaller than the current cooling capacity of the unit and larger than the minimum unloading capacity of the unit, if the indoor cooling load demand changes too much and the unloading speed of the unit is slower, the unit can be stopped by misjudgment. In addition, when the indoor cooling load demand changes and is smaller than the current refrigerating capacity of the unit, the unit is unloaded to the lowest unloading capacity. At this time, if the chilled water outlet temperature is not maintained at the set outlet temperature, the outlet temperature is continuously decreased. It is indicated that the indoor cooling load demand is less than the minimum unloading capacity of the unit, in which case the unit will be subjected to periodic start-stop control.

In view of the foregoing problems, as shown in fig. 1, an embodiment of the disclosure provides a method for controlling a water chiller, including:

s101, under the condition that the water chiller is continuously unloaded, the processor acquires the chilled water outlet temperature.

S102, the processor calculates a difference value between the outlet water temperature of the chilled water and a preset shutdown temperature, and judges whether the difference value is smaller than a preset threshold value.

And S103, if the difference value is smaller than a preset threshold value, the processor corrects the preset shutdown temperature to prolong the running time of the water chilling unit.

Here, the cooling load unloading means that the output load of the compressor in the refrigerant system of the chiller is reduced. Whether the compressor is in an unloaded state or not can be judged by the operation parameters of the compressor. For example, the judgment is made by parameters such as the operating frequency and the output power of the compressor. The determination of the sustained unloading may be determined by the operating parameters of the compressor over a period of time. If the operating frequency of the compressor is in a continuously decreasing state for a period of time, the water chiller is indicated to be in a state that the cooling load is continuously unloaded.

When the water chilling unit is in the continuous unloading state of the cold load, the water chilling unit has the risk of stopping or periodically starting and stopping by misjudgment. Therefore, in this case, the chilled water outlet temperature is detected by the temperature sensor. And further calculates the difference between the chilled water outlet temperature and the preset shutdown temperature. If the difference is greater than or equal to the preset threshold, the change of the outlet water temperature of the chilled water is slower. The unloading speed of the water chilling unit is faster than the change speed of the outlet water temperature of chilled water. Under the condition, the water chilling unit cannot be stopped by misjudgment. However, if the difference is less than the preset threshold, it indicates that the chilled water outlet temperature is changing faster. The indoor cooling load demand change amplitude is too large, and at the moment, the unloading speed of the water chilling unit is slower than the chilled water outlet temperature change speed. This will cause the chiller to be misjudged to be shut down. Therefore, in this case, the preset stop temperature is corrected to extend the operation time of the water chiller.

Specifically, the preset shutdown temperature is corrected downward, that is, the corrected preset shutdown temperature is smaller than the preset shutdown temperature before correction. If the preset shutdown temperature is T1, the corrected shutdown temperature is T1-a. Wherein, a can take a value of 2-4 ℃. Therefore, the value of the preset shutdown temperature is reduced, so that the time period when the outlet water temperature of the chilled water changes to the corrected preset shutdown temperature is longer than the time period required by the load unloading of the water chilling unit. Therefore, the problem of misjudgment of shutdown is solved, and the operation time of the water chilling unit is prolonged. Thus, after the water chilling unit is unloaded to the minimum unloading capacity, if the chilled water outlet temperature reaches the corrected preset shutdown temperature, the water chilling unit is shut down.

By adopting the method for controlling the water chilling unit provided by the embodiment of the disclosure, when the load of the water chilling unit is continuously reduced, whether the difference value between the chilled water outlet temperature and the preset shutdown temperature is smaller than the preset threshold value is judged. If it is smaller, it indicates that the chilled water temperature changes faster. When the water temperature change time is faster than the unloading time of the water chilling unit, the water chilling unit can be stopped by misjudgment. And restarting after the water temperature rises, so that periodic start and stop are repeatedly formed. To avoid this, the preset shutdown temperature is corrected when the above condition is satisfied. So as to prolong the running time of the water chilling unit and avoid misjudgment of shutdown. The start-stop times of the unit are reduced, and the energy efficiency of the system is improved.

Optionally, in step S101, the processor determines that the chiller is in continuous unloading of the cooling load by:

the sensor detects an operating rotational speed of the compressor.

And under the condition that the running rotating speed continuously decreases within a preset time period, the processor determines that the water chilling unit is in continuous unloading of the cold load.

Here, the operation rotation speed of the compressor may be detected by an angular velocity sensor. If the running speed of the compressor is detected to continuously decrease within the preset time period, the output load of the compressor is indicated to continuously decrease. The water chiller is in a state of continuously unloading the cooling load. In addition, whether the water chiller is in a continuous unloaded state can also be determined by detecting the operating frequency of the compressor. And if the running frequency of the compressor is continuously reduced within the preset duration, determining that the water chilling unit is in continuous unloading of the cold load.

As shown in conjunction with fig. 2, an embodiment of the present disclosure provides another method for controlling a water chiller, including:

S204, the processor acquires the opening degree of the load balancing valve.

S205, under the condition that the opening degree of the load balancing valve is the maximum opening degree, the processor judges whether the current outlet water temperature of the chilled water is smaller than the corrected preset shutdown temperature.

S206, if the current outlet water temperature is smaller than the corrected preset shutdown temperature, the processor controls the compressor of the water chilling unit to shutdown.

Here, after correcting the preset shutdown temperature, the opening degree of the load balancing valve is detected. The load balancing valve is arranged on a pipeline between the condenser and the evaporator of the refrigerant system, and the refrigerant flow direction in the pipeline is that the condenser flows to the evaporator. The opening degree of the load balancing valve can reflect the unloading condition of the cooling load of the water chilling unit. And if the opening degree of the load balancing valve is smaller than the maximum opening degree, indicating that the cooling load of the water chilling unit is larger than the minimum unloading capacity. In this case, the chiller may also continue to cool load off. And if the opening degree of the load balancing valve is the maximum opening degree, the cold load of the water chilling unit is reduced to the minimum unloading capacity. In this case, if the chilled water outlet temperature continues to decrease, the compressor of the chiller is shut down.

Specifically, whether the current outlet water temperature of the chilled water is smaller than the corrected preset shutdown temperature is judged. If not, the outlet water temperature of the chilled water can be maintained above the corrected preset shutdown temperature. And (3) keeping the current running state of the water chilling unit. If so, the outlet water temperature of the chilled water cannot be maintained at the corrected preset shutdown temperature. The indoor cooling load demand is smaller than the lowest unloading load of the water chilling unit, and the compressor of the water chilling unit is stopped to avoid the reduction of indoor temperature.

As shown in conjunction with fig. 3, an embodiment of the present disclosure provides another method for controlling a water chiller, including:

S204, the processor acquires the opening degree of the load balancing valve.

S307, the processor corrects the preset starting temperature of the chilled water to prolong the shutdown time of the water chiller.

S308, under the condition that the chilled water outlet temperature reaches the corrected preset starting temperature, the processor controls the compressor to operate at the target rotating speed.

Here, when the indoor cooling load demand is smaller than the lowest unloading load of the chiller, the outlet water temperature of the chilled water fluctuates in a range between the corrected preset shutdown temperature and the preset startup temperature after the compressor of the chiller is shutdown. The water chiller will start and stop periodically, which will seriously impair the performance of the compressor. In order to further reduce the number of times of periodic starting of the water chilling unit, the preset starting temperature is corrected. So as to prolong the shutdown time of the water chilling unit, namely, upwardly correcting the preset starting temperature. If the preset starting temperature before correction is T2, the preset starting temperature after correction is T2+b. Wherein, the value of b can be equal to a or different. Therefore, after the compressor is stopped, the stop time of the water chilling unit is prolonged by correcting the preset starting temperature. And after the compressor is started, the operation time of the water chilling unit is prolonged through the corrected preset shutdown temperature. Therefore, the cold accumulation amount of water in the water chilling unit is improved by enlarging the start-stop temperature difference. Thereby prolonging the running time and the stopping time of the water chilling unit, prolonging the start-stop period of the compressor and reducing the frequent start-stop times.

Further, when the compressor is stopped and the chilled water outlet temperature reaches the corrected preset starting temperature, the compressor is started again. At this time, the compressor is controlled to operate at a target rotational speed. Here, a target rotational speed of the compressor is set, wherein the target rotational speed is smaller than a maximum operation rotational speed of the compressor. I.e., controlling the chiller to operate at less than the maximum load capacity. Therefore, on one hand, the operation time of the unit can be prolonged, and the frequency of frequent start and stop of the unit is reduced. On the other hand, the running efficiency of the unit can be improved under the low-load working condition, and the power consumption is reduced to realize energy conservation.

Optionally, in S308, the processor determines the target rotational speed of the compressor by:

the processor obtains rated load of the water chilling unit.

The processor determines that the target load of the start of the water chilling unit is the product of the rated load and a preset coefficient.

And the processor determines a target rotating speed corresponding to the target load according to the corresponding relation between the load and the rotating speed.

Here, the target load for starting is determined based on the rated load of the water chiller. And under the low-load working condition, the water chilling unit operates at a target load smaller than the rated load. The indoor cooling load demand can be met, the running time can be prolonged, and the start-stop times can be reduced. The preset coefficient A mainly depends on the model of the water chilling unit, and the value range is 60% -70%. I.e. target load = rated load a.

As shown in conjunction with fig. 4, an embodiment of the present disclosure provides another method for controlling a water chiller, including:

S404, under the condition that the compressor of the water chilling unit is stopped and restarted, the processor judges whether the indoor cooling load demand in unit time is greater than the lowest unloading load of the water chilling unit.

And S405, if the indoor cooling load demand in unit time is greater than the lowest unloading load of the water chilling unit, the processor controls the running rotating speed of the compressor in the water chilling unit according to the indoor cooling load demand.

Here, after the preset shutdown temperature is corrected, if the chilled water outlet temperature is continuously reduced and less than the corrected preset shutdown temperature, the compressor is shutdown. At this time, the indoor cooling load demand is smaller and smaller than the minimum unloading capacity of the chiller. When the chilled water temperature of the chiller reaches the preset starting temperature, the compressor is started again (wherein the preset starting temperature may be the preset starting temperature corrected in the foregoing). At this time, it is necessary to determine the amount of indoor cooling load demand. If the low load condition is still present, the compressor is controlled at the target speed as previously indicated. And if the indoor cold load demand is greater than the lowest load shedding of the water chilling unit, indicating that the current working condition is no longer a low load working condition. At this time, the running rotation speed of the compressor can be controlled according to the indoor cooling load demand, namely, the water chiller is restored to the normal running state.

The indoor cooling load demand refers to indoor cooling load demand in unit time. The indoor cooling load demand can be calculated through the indoor real-time temperature and the set temperature. And calculating the indoor cooling load demand amount in unit time based on the temperature change duration.

Optionally, in step S404, the processor determines the indoor cooling load demand per unit time by:

the processor obtains the time period from the stop of the compressor to the restart and the total heat released by the chilled water in the process.

The processor determines the amount of indoor cooling load demand per unit time per unit of heat released by the chilled water over a period of time.

Here, under the low load condition, after the compressor is stopped, the chilled water temperature fluctuates between the corrected preset stop temperature and the corrected preset start temperature. The heat released by the chilled water temperature at this stage from shut down to start up can be calculated. For example, the chilled water temperature at the time of stop is set to T1-a, and the chilled water temperature at the time of start is set to T2-b. The total heat released by the chilled water during this period of time is q=cm ((T2-b) - (T1-a)), where c is the specific heat capacity and m is the mass. During the period t from the stop of the compressor to the restart ₀ In, the unit heat released by chilled water q=q/t ₀ . Q is taken as the indoor cooling load requirement in unit time. Thus, when the indoor cold load demand is higher, the chilled water temperature control mode under the low load working condition is exited. The compressor resumes normal operation.

Referring to fig. 5, an embodiment of the disclosure provides an apparatus for controlling a water chiller, which includes an obtaining module 51, a judging module 52, and a correcting module 53. The acquisition module 51 is configured to acquire chilled water outlet temperature with the chiller in a continuous unloaded condition of the chiller. The determination module 52 is configured to calculate a difference between the chilled water outlet temperature and a preset shutdown temperature and determine whether the difference is less than a preset threshold. The correction module 53 is configured to correct the preset shutdown temperature to extend the chiller run length if the difference is less than the preset threshold.

By adopting the device for controlling the water chilling unit provided by the embodiment of the disclosure, when the load of the water chilling unit is continuously reduced, the judging module judges whether the difference value between the chilled water outlet temperature and the preset shutdown temperature is smaller than the preset threshold value. If it is smaller, it indicates that the chilled water temperature changes faster. When the water temperature change time is faster than the unloading time of the water chilling unit, the water chilling unit can be stopped by misjudgment. And restarting after the water temperature rises, so that periodic start and stop are repeatedly formed. To avoid this, the correction module corrects the preset shutdown temperature when the above condition is satisfied. So as to prolong the running time of the water chilling unit and avoid misjudgment of shutdown. The start-stop times of the unit are reduced, and the energy efficiency of the system is improved.

As shown in connection with fig. 6, an embodiment of the present disclosure provides an apparatus for controlling a chiller, including a processor (processor) 100 and a memory (memory) 101. Optionally, the apparatus may further comprise a communication interface (Communication Interface) 102 and a bus 103. The processor 100, the communication interface 102, and the memory 101 may communicate with each other via the bus 103. The communication interface 102 may be used for information transfer. Processor 100 may invoke logic instructions in memory 101 to perform the method for controlling a chiller in accordance with the above-described embodiments.

Further, the logic instructions in the memory 101 described above may be implemented in the form of software functional units and may be stored in a computer readable storage medium when sold or used as a stand alone product.

The memory 101 is a computer readable storage medium that can be used to store a software program, a computer executable program, such as program instructions/modules corresponding to the methods in the embodiments of the present disclosure. The processor 100 executes functional applications and data processing by running program instructions/modules stored in the memory 101, i.e., implements the method for controlling a chiller in the above-described embodiments.

The memory 101 may include a storage program area and a storage data area, wherein the storage program area may store an operating system, at least one application program required for a function; the storage data area may store data created according to the use of the terminal device, etc. Further, the memory 101 may include a high-speed random access memory, and may also include a nonvolatile memory.

The embodiment of the disclosure provides a water chilling unit, which comprises the device for controlling the water chilling unit.

The disclosed embodiments provide a storage medium storing computer executable instructions configured to perform the above-described method for controlling a chiller.

The storage medium may be a transitory computer readable storage medium or a non-transitory computer readable storage medium.

Embodiments of the present disclosure may be embodied in a software product stored on a storage medium, including one or more instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of a method according to embodiments of the present disclosure. And the aforementioned storage medium may be a non-transitory storage medium including: a plurality of media capable of storing program codes, such as a usb disk, a removable hard disk, a Read-Only Memory (ROM), a random access Memory (RAM, random Access Memory), a magnetic disk, or an optical disk, or a transitory storage medium.

The above description and the drawings illustrate embodiments of the disclosure sufficiently to enable those skilled in the art to practice them. Other embodiments may involve structural, logical, electrical, process, and other changes. The embodiments represent only possible variations. Individual components and functions are optional unless explicitly required, and the sequence of operations may vary. Portions and features of some embodiments may be included in, or substituted for, those of others. Moreover, the terminology used in the present application is for the purpose of describing embodiments only and is not intended to limit the claims. As used in the description of the embodiments and the claims, the singular forms "a," "an," and "the" (the) are intended to include the plural forms as well, unless the context clearly indicates otherwise. Similarly, the term "and/or" as used in this application is meant to encompass any and all possible combinations of one or more of the associated listed. Furthermore, when used in this application, the terms "comprises," "comprising," and/or "includes," and variations thereof, mean that the stated features, integers, steps, operations, elements, and/or components are present, but that the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof is not precluded. Without further limitation, an element defined by the phrase "comprising one …" does not exclude the presence of other like elements in a process, method or apparatus comprising such elements. In this context, each embodiment may be described with emphasis on the differences from the other embodiments, and the same similar parts between the various embodiments may be referred to each other. For the methods, products, etc. disclosed in the embodiments, if they correspond to the method sections disclosed in the embodiments, the description of the method sections may be referred to for relevance.

Those of skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the solution. The skilled artisan may use different methods for each particular application to achieve the described functionality, but such implementation should not be considered to be beyond the scope of the embodiments of the present disclosure. It will be clearly understood by those skilled in the art that, for convenience and brevity of description, specific working procedures of the above-described systems, apparatuses and units may refer to corresponding procedures in the foregoing method embodiments, which are not repeated herein.

In the embodiments disclosed herein, the disclosed methods, articles of manufacture (including but not limited to devices, apparatuses, etc.) may be practiced in other ways. For example, the apparatus embodiments described above are merely illustrative, and for example, the division of the units may be merely a logical function division, and there may be additional divisions when actually implemented, for example, multiple units or components may be combined or integrated into another system, or some features may be omitted, or not performed. In addition, the coupling or direct coupling or communication connection shown or discussed with each other may be through some interface, device or unit indirect coupling or communication connection, which may be in electrical, mechanical or other form. The units described as separate units may or may not be physically separate, and units shown 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 units may be selected according to actual needs to implement the present embodiment. In addition, each functional unit in the embodiments of the present disclosure may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit.

The flowcharts and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods and computer program products according to embodiments of the present disclosure. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). In some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. In the description corresponding to the flowcharts and block diagrams in the figures, operations or steps corresponding to different blocks may also occur in different orders than that disclosed in the description, and sometimes no specific order exists between different operations or steps. For example, two consecutive operations or steps may actually be performed substantially in parallel, they may sometimes be performed in reverse order, which may be dependent on the functions involved. Each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems which perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.

Claims

1. A method for controlling a chiller, comprising:

under the condition that the water chilling unit is continuously unloaded with the cold load, obtaining the outlet water temperature of chilled water;

calculating a difference value between the outlet water temperature of the chilled water and a preset shutdown temperature, and judging whether the difference value is smaller than a preset threshold value or not;

and if the difference value is smaller than a preset threshold value, correcting the preset shutdown temperature to prolong the running time of the water chilling unit.

2. The method of claim 1, wherein the chiller is determined to be at a continuous cold load off-load by:

detecting the running rotation speed of the compressor;

and under the condition that the running rotating speed continuously decreases within the preset duration, determining that the water chilling unit is in continuous unloading of the cooling load.

3. The method of claim 1, wherein a load balancing valve is arranged on a pipeline between a condenser and an evaporator of the chiller; after correcting the preset shutdown temperature, the method further comprises the following steps:

acquiring the opening degree of the load balancing valve;

judging whether the current outlet water temperature of the chilled water is smaller than the corrected preset shutdown temperature or not under the condition that the opening of the load balancing valve is the maximum opening;

and if the current outlet water temperature is smaller than the corrected preset shutdown temperature, controlling the compressor of the water chilling unit to shutdown.

4. The method of claim 3, wherein after the compressor of the chiller is stopped, further comprising:

correcting the preset starting temperature of the chilled water to prolong the shutdown time of the water chilling unit;

and under the condition that the chilled water outlet temperature reaches the corrected preset starting temperature, controlling the compressor to run at the target rotating speed.

5. The method of claim 4, wherein the target rotational speed is determined by:

acquiring rated load of the water chilling unit;

determining that the target load of starting the water chilling unit is the product of rated load and a preset coefficient;

and determining the target rotating speed corresponding to the target load according to the corresponding relation between the load and the rotating speed.

6. The method according to any one of claims 1 to 5, further comprising:

judging whether the indoor cooling load demand in unit time is greater than the lowest unloading load of the water chilling unit under the condition that the compressor of the water chilling unit is stopped and restarted;

and if the indoor cooling load demand amount in unit time is larger than the lowest unloading load of the water chilling unit, controlling the running rotating speed of the compressor of the water chilling unit according to the indoor cooling load demand amount.

7. The method of claim 6, wherein the indoor cooling load demand per unit time is determined by:

acquiring the time from stopping to restarting of the compressor and the total heat released by the chilled water in the process;

and determining the indoor cooling load demand quantity in unit time of the unit heat released by the chilled water in the time period.

8. An apparatus for controlling a water chiller comprising a processor and a memory storing program instructions, wherein the processor is configured to perform the method for controlling a water chiller as claimed in any one of claims 1 to 7 when the program instructions are run.

9. A control chiller comprising the apparatus for controlling a chiller as set forth in claim 8.

10. A storage medium storing program instructions which, when executed, perform the method for controlling a chiller as claimed in any one of claims 1 to 7.