WO2023005451A1

WO2023005451A1 - Control method for water chilling unit

Info

Publication number: WO2023005451A1
Application number: PCT/CN2022/098109
Authority: WO
Inventors: 王超; 安普光; 张捷; 徐龙靖
Original assignee: 青岛海尔空调电子有限公司; 青岛海尔空调器有限总公司; 海尔智家股份有限公司
Priority date: 2021-07-30
Filing date: 2022-06-10
Publication date: 2023-02-02
Also published as: CN113654134B; CN113654134A

Abstract

The present invention relates to the technical field of air conditioners. Specifically provided is a control method for a water chilling unit, which method aims to solve the problem, in an existing control method for a water chilling unit, of increased power consumption caused by frequent start and stop of a water chilling unit. For this purpose, whether a water chilling unit meets a set condition is determined, and when the water chilling unit meets the set condition, a target water outlet temperature Tx is re-determined, and is made higher than an original target water outlet temperature T0. When the water chilling unit runs in a chilling mode according to the re-determined target water outlet temperature Tx, the water chilling unit can quickly achieve load shedding, so as to avoid the problem of the water chilling unit being shut down due to an actual water outlet temperature of chilled water quickly becoming lower than a shutdown temperature Tt caused by the mismatch between the load shedding speed of the water chilling unit and a load demand reduction speed when the water chilling unit is controlled according to the original target temperature T0, thereby avoiding the problem of increased power consumption caused by frequent start and stop of the water chilling unit.

Description

Control method of chiller

technical field

The invention relates to the technical field of air conditioning, and specifically provides a method for controlling a chiller.

Background technique

Chillers include refrigerant systems, cooling water systems and chilled water systems. When the chiller is cooling the room, the compressor of the refrigerant system drives the refrigerant to circulate between the condenser and the evaporator, and an electronic expansion valve is installed between the condenser and the evaporator. The exhaust port enters the condenser and flows to the evaporator after passing through the electronic expansion valve, and finally flows back from the outlet of the evaporator to the suction port of the compressor to complete a refrigerant cycle.

The condenser radiates heat to the outside, and the cooling water heat exchanger in the cooling water system exchanges heat with the above condenser, and the cooling water pump drives the water in the cooling water system to flow between the cooling water heat exchanger and the outdoor cooling tower , in order to achieve the purpose of cooling and cooling the condenser. At the same time, the evaporator generates refrigeration by its external heat absorption, the chilled water heat exchanger in the chilled water system exchanges heat with the above-mentioned evaporator, and the chilled water pump drives the water in the chilled water system to flow in the chilled water heat exchanger It flows between the indoor heat exchanger, and the fan configured on the indoor heat exchanger drives the indoor air to exchange heat with the indoor heat exchanger, so as to achieve the purpose of cooling the room by absorbing the heat in the room through the indoor heat exchanger.

In a commercial chiller, multiple indoor heat exchangers are connected to the chilled water heat exchanger, and it is usually necessary to control the working parameters of the chiller according to the set chilled water target outlet temperature. When the number of indoor heat exchangers turned on increases, the indoor demand load becomes larger, and the chiller needs to increase the operating frequency to make the actual outlet temperature of chilled water reach the target outlet temperature to ensure the cooling effect; when the number of indoor heat exchangers turned on When the indoor demand load decreases, the chiller needs to reduce the operating frequency to make the actual outlet temperature of chilled water reach the target outlet temperature to avoid energy waste.

In the existing chiller cooling control method, when the indoor demand load is small, the actual outlet temperature of the chilled water will decrease, and when the outlet temperature of the chilled water drops to the shutdown temperature, the control chiller will stop, that is, the compressor will stop running. And, after the chiller is shut down, the chilled water pump continues to run to continuously cool the indoor environment. At the same time, the temperature of the chilled water will increase. When the temperature of the chilled water rises to the start-up temperature of the chiller, the chiller is controlled to start.

However, after the chiller is started, the actual outlet temperature of the chilled water will drop to the shutdown temperature in a short period of time, causing the chiller to shut down again. Repeatedly, the frequent start and stop of the chiller will increase the power consumption, and the temperature fluctuation of the indoor air outlet will also reduce the indoor comfort.

Correspondingly, there is a need in the art for a new control method for chillers to solve the above problems.

Contents of the invention

The present invention aims to solve the above-mentioned technical problems, that is, to solve the problems existing in the existing chiller control method that frequent startup and shutdown of the chiller leads to increased power consumption, and the fluctuation of the indoor air outlet temperature also leads to a decrease in indoor comfort. The invention provides a control method of a chiller.

In the control method provided by the present invention, the control method includes: obtaining the actual outlet water temperature Tout _of the chilled water of the chiller, and the historical outlet water temperature T1 before the set time period _tb _; judging the Whether _the above-mentioned chiller meets _the setting condition Tout<T ₀ and T ₁ -Tout ≥ K ₁ ; among them, T ₀ is the target outlet water temperature currently set, and k ₁ is the normal temperature of the outlet water temperature within the set time period t _b change threshold; and k ₁ >0; if the chiller meets the set conditions, re-determine the target outlet water temperature T _x =T ₀ +K ₂ ; wherein, K ₂ >0 and is a constant; control the chilled water The unit performs cooling operation according to the re-determined target outlet water temperature _Tx .

As a preferred technical solution of the above-mentioned control method provided by the present invention, the actual _inlet water temperature Tx of the chilled water of the chiller is also obtained; after re-determining the target outlet water temperature Tx, the temperature of the chiller _is also calculated The adjustment rate V of the target outlet water temperature; wherein, V=(T _in -T _out )*(T ₁ -T _out )*K ₃ ; the unit of V is ℃/s, wherein K ₃ is a constant; control the chiller The target outlet water temperature is changed from T ₀ to T _x at the adjustment speed V.

As a preferred technical solution of the above-mentioned control method provided _by the present invention, the step of "controlling the chiller to perform cooling operation according to the re-determined target outlet water temperature Tx" includes: The compressor is controlled according _to the mapping relationship between at least one parameter of the number of starts, the operating frequency and the load energy and the temperature difference (Tx- _Tout ); and/or, according to the preset temperature of the chiller The outdoor fan is controlled according _to the mapping relationship between the number of outdoor fans turned on or the rotational speed and the temperature difference (Tx- _Tout ); and/or, according to the preset rotational speed and temperature difference of the cooling water pump of the chiller The mapping relationship of _the value (Tx- _Tout ) controls the cooling water pump.

As a preferred technical solution of the above-mentioned control method provided _by the present invention, the step of "controlling the chiller to perform cooling operation according to re-determining the target outlet water temperature Tx" includes: reducing the number of compressors of the chiller to be turned on , at least one parameter of operating frequency and load energy; and/or, reducing the number or rotation speed of the outdoor fan of the chiller; and/or, reducing the speed of the cooling water pump of the chiller.

As a preferred technical solution of the above control method provided by the present invention, after the step of "controlling the chiller to perform cooling operation according to the re-determined target outlet water temperature Tx", it also includes: when the chiller _is shut down and restarted, , reset the target outlet water temperature to T ₀ , and control the chiller to perform cooling operation according to the reset target outlet water temperature T ₀ .

As a preferred technical solution of the above-mentioned control method provided by the present invention, before re-determining the target outlet water temperature, it also includes: obtaining the current time; judging whether the current time is within the set fast load shedding time period; if so, then Re-determine the target outlet water temperature.

As a preferred technical solution of the above control method provided by the present invention, before re-determining the target outlet water temperature, it also includes: obtaining the current load rate of the chiller; comparing the current load rate with the set load rate threshold Comparing; if the current load rate is less than the load rate threshold, then re-determine the target outlet water temperature.

As a preferred technical solution of the above control method provided by the present invention, after judging whether the chiller meets the set condition, it further includes: if the chiller does not meet the set condition, controlling the The above-mentioned chiller maintains the currently set target outlet water temperature T ₀ and continues to operate.

As a preferred technical solution of the above-mentioned control method provided by the present invention, the set time period t _b should satisfy: t _b ≤ t ₀ , where t ₀ is the actual water outlet required before the set control chiller shuts down The temperature Tout is the time required _to maintain the set shutdown temperature _Tt .

As a preferred technical solution of the above-mentioned control method provided by the present invention, the constant K ₂ should satisfy: 0<K ₂ ≤ 3T _z , where T _z is the currently set shutdown temperature difference, and T _z =T ₀ -T _t .

In the case of adopting the above technical solution, the present invention judges whether the chiller meets the set condition, and when the chiller satisfies the set condition, it indicates that the cooling load demand on the user side is rapidly decreasing. In the present invention, the re-determined target water outlet temperature Tx _is higher than the original target water outlet temperature T ₀ , and when the chiller unit performs cooling operation according to the re-determined target water outlet temperature, the chiller unit can be quickly unloaded to avoid The target temperature T ₀ is used to control the chiller, but due to the mismatch between the load reduction speed of the chiller and the reduction speed of the load demand, the actual outlet temperature of the chilled water is quickly lower than the shutdown temperature T _t , resulting in the shutdown of the chiller question. The invention can avoid the problems of increased power consumption caused by frequent start and stop of the chiller and reduced indoor comfort caused by fluctuations in the temperature of the indoor outlet air.

In addition, in the control method of the chiller provided by the present invention, after re-determining the target outlet water temperature Tx, the adjustment rate V of the target outlet water temperature of the chiller _is also calculated, and the adjustment rate V is different from the actual inlet and outlet water temperature difference ( T _in -T _out ) and the difference between the reduction of chilled water in the set time period t _b (T ₁ -T _out ) are both proportional. By controlling the chilled water target outlet temperature of the chiller to change at a certain adjustment speed, instead of directly modifying the original target outlet water temperature T ₀ to re-determine the target outlet water temperature T _x , the stability and cooling effect of the chiller can be guaranteed And avoid the problem that the temperature of the air outlet of the indoor unit fluctuates greatly and affects the user experience. It can be understood that the larger the actual temperature difference _between the _inlet and outlet of the chilled water (Tin-Tout), that is, the higher the inlet temperature of the chilled water and the lower the outlet temperature of the chilled water, the greater the cooling load on the user side. After the water absorbs heat from the indoor environment with a large cooling load on the user side, the outlet temperature of the chilled water is still low. The chilled water outlet temperature is adjusted to re-determine the target outlet water temperature T _x ; at the same time, the greater the difference (T ₁ -T _out ) of the chilled water decrease within the set time period t _b , the greater the cooling load on the user side The greater the speed, the chiller needs to adjust the chilled water outlet temperature to the re-determined target outlet water temperature T _x at a faster adjustment speed, so that the chiller's load reduction speed matches the load demand reduction speed, avoiding freezing The actual outlet temperature of the water is soon lower than the shutdown temperature T _t , which causes the chiller to shut down.

Description of drawings

The disclosure of the present invention will become more comprehensible with reference to the accompanying drawings. Those skilled in the art can easily understand that: these drawings are only for the purpose of illustration, and are not intended to limit the protection scope of the present invention. In the attached picture:

Fig. 1 is the structural representation of the chiller unit of the present embodiment;

Fig. 2 is a schematic flowchart of the control method of the water chiller in this embodiment.

List of reference signs

1-compressor; 2-condenser; 3-evaporator; 4-electronic expansion valve; 5-cooling water heat exchanger; 6-cooling tower; 7-chilled water heat exchanger; 8-indoor heat exchanger; 91 - Cooling water pump; 92 - Chilled water pump.

Detailed ways

Preferred embodiments of the present invention are described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present invention, and are not intended to limit the protection scope of the present invention.

It should be noted that, in the description of the present invention, unless otherwise clearly stipulated and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection. Connected, or integrally connected; it may be mechanically connected or electrically connected; it may be directly connected or indirectly connected through an intermediary, and it may be the internal communication of two components. Those skilled in the art can understand the specific meanings of the above terms in the present invention according to specific situations.

In order to describe the control method of the chiller in the present invention clearly and in detail, the basic structure and working principle of the chiller will be briefly described in conjunction with the chiller shown in FIG. 1 .

Chillers generally include a refrigerant system, a cooling water system and a chilled water system. When the chiller is cooling the room, the compressor 1 of the refrigerant system drives the refrigerant to circulate between the condenser 2 and the evaporator 3, and an electronic expansion valve 4 is installed between the condenser 2 and the evaporator 3, The refrigerant first enters the condenser 2 from the exhaust port of the compressor 1 and flows to the evaporator 3 after passing through the electronic expansion valve 4, and finally flows back from the outlet of the evaporator 3 to the suction port of the compressor 1 to complete a refrigerant cycle. Arrows in FIG. 1 show the flow path of the refrigerant.

The condenser 2 radiates heat to its outside, and the cooling water heat exchanger 5 in the cooling water system exchanges heat with the above-mentioned condenser 2, and the cooling water pump 91 drives the water in the cooling water system to flow between the cooling water heat exchanger 5 and the outdoor Flow between the cooling towers 6 to achieve the purpose of cooling the condenser 2 to dissipate heat.

At the same time, the evaporator 3 generates refrigeration by its external heat absorption, the chilled water heat exchanger 7 in the chilled water system exchanges heat with the above-mentioned evaporator 3, and the chilled water pump 92 drives the water in the chilled water system to freeze The water flows between the heat exchanger 7 and the indoor heat exchanger 8, and the indoor fan (not shown in the figure) arranged on the indoor heat exchanger 8 drives the indoor air to exchange heat with the indoor heat exchanger 8, so as to achieve heat exchange through the indoor heat exchanger 8. Heater 8 absorbs the heat in the room for the purpose of cooling the room. It should be noted that multiple indoor heat exchangers 8 are connected to the chilled water heat exchanger 7 in the water chiller of this embodiment, but this embodiment only shows 6 four indoor heat exchangers 8, but in practice There can be many indoor heat exchangers 8 in the water chiller, and the chilled water inlet or outlet of each indoor heat exchanger 8 is provided with a corresponding valve, which controls the opening and closing of the indoor unit.

In a commercial chiller, multiple indoor heat exchangers 8 are connected to the chilled water heat exchanger 7, and it is usually necessary to control the working parameters of the chiller according to the set chilled water target outlet temperature. When the number of indoor heat exchangers 8 turned on increases, the cooling load required in the room becomes larger, and the chiller can make the actual outlet water temperature of the chilled water reach the target outlet water temperature by loading, so as to ensure the cooling effect; when the indoor heat exchanger 8 is turned on When the quantity decreases, the cooling load required in the room decreases, and the chiller needs to reduce the load to make the actual outlet temperature of chilled water reach the target outlet temperature to avoid energy waste.

In the existing chiller control method, when the indoor demand load is small, the actual chilled water outlet temperature will decrease, and when the chilled water outlet temperature drops to the shutdown temperature, the chiller must be controlled to stop, that is, the compressor 1 stops running. And, after the chiller is shut down, the chilled water pump 92 continues to run to continuously cool the indoor environment. At the same time, the temperature of the chilled water rises. When the temperature of the chilled water rises to the start-up temperature of the chiller, the chiller is controlled to start.

However, after the chiller is started, the actual outlet temperature of the chilled water will drop to the shutdown temperature in a short period of time, causing the chiller to shut down again. Repeatedly, the frequent start and stop of the chiller will lead to an increase in power consumption, and the fluctuation of the indoor outlet air temperature will also lead to a decrease in indoor comfort.

This embodiment aims to solve the above-mentioned technical problems, that is, to solve the problems existing in the existing chiller control method that frequent startup and shutdown of the chiller leads to increased power consumption, and fluctuations in the temperature of the indoor outlet air also lead to a decrease in indoor comfort. This embodiment provides a method for controlling a water chiller.

As shown in Figure 2, in the control method provided in this embodiment, the control method includes:

S1. Obtain the actual outlet water temperature Tout _of the chilled water _of the chiller, and the historical outlet water temperature T1 before the set time period _tb .

It should be noted that the set time period t _b involved in step S1 should preferably satisfy: t _b ≤ t ₀ , where t ₀ is the set control chiller before shutting down and requiring the actual outlet water temperature T _out to be kept less than or equal to the set shut down The time required for temperature T _t . t ₀ is generally 1 to 2 minutes. Exemplarily, the parameter t _b here may be set to 30s. In this way, the detection frequency of the outlet temperature of the chilled water is determined according to the duration of the set stop temperature, which can better ensure that the abnormal change of the cooling load on the user side can be detected in time before the chiller is shut down, and the chiller can be controlled in time To avoid frequent start and stop of the chiller.

S2. Judging whether the chiller meets _the set condition Tout< _T0 and T1 _- _Tout≥K1 _; among them, _T0 is the target outlet water temperature currently set, and _k1 is the outlet water temperature within the set time period t _b The normal change threshold of , and k ₁ >0.

It should be noted _that if Tout ≥ T ₀ , it means that the chiller needs to be loaded to reduce the outlet temperature of the chilled water to the target outlet temperature. At this time, the chiller has no risk of shutdown, so no subsequent steps are required. In addition, if T ₁ _-Tout <K ₁ , it means that the cooling load demand on the user side is a normal load reduction, and there is no need to adjust the target outlet water temperature of the chilled water of the chiller, and the chiller is normally cooled according to the original target outlet water temperature There will be no shutdown of the chiller during operation.

S3. If the chiller meets the setting conditions, re-determine the target outlet water temperature T _x =T ₀ +K ₂ ; wherein, K ₂ >0 and is a constant.

It should be noted that the constant K ₂ involved in step S1 preferably satisfies: 0<K ₂ ≤3T _z , where T _z is the currently set shutdown temperature difference, and generally, K ₂ can be determined to be equal to T _z . In addition, T _z =T ₀ -T _t , that is, when the chilled water outlet temperature is less than or equal to the shutdown temperature T _t and the set shutdown time t ₀ is maintained, the chiller will shut down.

S4. Control the chiller to perform cooling operation according to the re-determined target outlet water temperature _Tx .

Exemplarily, step S4 may include: according to the preset mapping relationship between at least one parameter among the number of start-ups of the compressors of the chiller, operating frequency and load energy, and _the temperature difference (Tx- _Tout ) and/or, control the outdoor fan according to the preset mapping relationship between _the number of openings of the outdoor fan of the chiller or the rotational speed and the temperature difference (Tx- _Tout ); and/or, according to the preset The mapping relationship between _the rotational speed of the cooling water pump of the chiller and the temperature difference (Tx- _Tout ) controls the cooling water pump.

At the same time, step S4 includes: reducing at least one parameter among the number of compressors turned on, the operating frequency and the load energy of the chiller; and/or, reducing the number or speed of the outdoor fan of the chiller; and/or, reducing The speed of the cooling water pump of the small chiller.

It should be noted that the greater the temperature difference (T _x -T _out ), the greater the decrease in the frequency of the compressor, the speed of the outdoor fan, and the speed of the cooling water pump. This control logic belongs to the internal control logic of the magnetic levitation compressor , only a brief theoretical explanation is given here.

In the case of adopting the above-mentioned embodiment, in this embodiment, by judging whether the chiller meets the set condition, when the chiller satisfies the set condition, it indicates that the cooling load demand on the user side is decreasing rapidly. In this embodiment, the re-determined target outlet water temperature T _{x is} higher than the original target outlet water temperature T ₀ . The target temperature T ₀ of the chiller is used to control the chiller, but the actual outlet temperature of the chilled water is quickly lower than the shutdown temperature T _t due to the mismatch between the load reduction speed of the chiller and the reduction speed of the load demand, causing the chiller to shut down The problem. This embodiment can avoid the problems of increased power consumption caused by the frequent start and stop of the chiller and a decrease in indoor comfort caused by fluctuations in the indoor outlet air temperature.

As a preferred implementation manner of the above control method provided in this embodiment, the following steps are further included: S101. Obtain the actual _inlet water temperature Tin of the chilled water of the chiller.

Before step S4, it also includes: S31, calculating the adjustment rate V of the target outlet water temperature of the chiller; wherein, V=( _Tin -Tout) _* (T1 _- Tout)*K3 _; _the unit of V is °C /s, where K ₃ is a constant;

Step S4 further includes: S41, controlling the target outlet water temperature of the chiller to change from T ₀ to T _x at an adjustment speed V.

It should be noted that step S101 only needs to be executed before step S4. For example, step S101 may be executed synchronously with step S1, or may be executed after step S3.

In the control method of the chiller provided in this embodiment, after re-determining the target outlet water temperature Tx, the adjustment rate V of the target outlet water temperature of the chiller _is also calculated, and the adjustment rate V is different from the actual inlet and outlet water temperature difference (T In-T _out ) and the difference _between the reduction of chilled water in the set time period t _b (T ₁ -T _out ) are both proportional. By controlling the chilled water target outlet temperature of the chiller to change at a certain adjustment speed, instead of directly modifying the original target outlet water temperature T ₀ to re-determine the target outlet water temperature T _x , the stability and cooling effect of the chiller can be guaranteed And avoid the problem that the temperature of the air outlet of the indoor unit fluctuates greatly and affects the user experience. It can be understood that the larger the actual temperature difference _between the _inlet and outlet of the chilled water (Tin-Tout), that is, the higher the inlet temperature of the chilled water and the lower the outlet temperature of the chilled water, the greater the cooling load on the user side. After the water absorbs heat from the indoor environment with a large cooling load on the user side, the outlet temperature of the chilled water is still low. The chilled water outlet temperature is adjusted to re-determine the target outlet water temperature T _x ; at the same time, the greater the difference (T ₁ -T _out ) of the chilled water decrease within the set time period t _b , the greater the cooling load on the user side The greater the speed, the chiller needs to adjust the chilled water outlet temperature to the re-determined target outlet water temperature T _x at a faster adjustment speed, so that the chiller's load reduction speed matches the load demand reduction speed, avoiding freezing The actual outlet temperature of the water is soon lower than the shutdown temperature T _t , which causes the chiller to shut down.

As a preferred implementation of the above control method provided in this embodiment, after step S4, it also includes: after the chiller is shut down and restarted, reset the target outlet water temperature to T ₀ , and control the chiller to follow the reset The target outlet water temperature T ₀ for cooling operation.

As a preferred implementation of the above-mentioned control method provided in this embodiment, after step S2, it also includes: if the chiller does not meet the set conditions, then control the chiller to maintain the currently set target outlet water temperature T ₀ to continue running .

It should be noted that the above-mentioned solution of controlling the chiller by adjusting the target temperature in this embodiment is to solve the problem of frequent cooling of the chiller when the cooling load demand on the user side decreases too quickly during the operation of the chiller. Temporary control schemes adopted for downtime problems. When the chiller is running normally, it can be controlled according to the default target outlet water temperature T ₀ .

In order to more accurately judge the phenomenon that the cooling load demand on the user side is shedding too quickly, and to avoid the abuse of the above-mentioned control scheme in this embodiment, as a preferred implementation of the above-mentioned control method provided in this embodiment, in step S3 Previously, also included:

S311. Obtain the current time.

S312, judging whether the current time is within the set fast load shedding time period.

S313. If yes, re-determine the target outlet water temperature.

It should be noted that commercial air conditioners generally experience excessive load shedding of chiller units during the peak hours of off-duty business hours. For example, the set fast load shedding time period can be from 17:00 to 19:00 in the afternoon; while for air conditioners in residential areas Generally, before the user goes to bed, there are many phenomena that the load reduction speed of the chiller is too fast. For example, the set fast load reduction time period can be from 22:00 to 24:00 in the evening. By judging whether the current time is within the set fast load shedding time period, the rapid load shedding demand of the chiller can be judged more timely and accurately, and the purpose of preventing frequent start and stop of the chiller can be further reliably realized.

S321. Obtain the current load rate of the chiller;

S322. Comparing the current load rate with a set load rate threshold;

S323. If the current load rate is less than the load rate threshold, re-determine the target outlet water temperature.

Exemplarily, the above load rate threshold may be 60%, that is, when less than 60 indoor units out of 100 indoor units are turned on, the above control scheme of this embodiment is executed. It should be noted that in the chiller, the magnetic levitation compressor is more energy-saving when the cooling load is smaller. When the cooling load is high, the chiller needs to continue to reduce the load, so as to realize energy saving by reducing the load of the chiller and avoid frequent start-up. stop purpose.

It should be noted that although the detailed steps of the method of the present invention have been described in detail above, those skilled in the art can combine, split and change the order of the above steps without departing from the basic principles of the present invention, such The modified technical solution does not change the basic idea of the present invention, so it also falls within the protection scope of the present invention. For example, as long as steps S311 to S313 and steps S321 to S323 are executed before S3, step 2 may be executed when the conditions in steps S313 and/or S323 are met; in addition, after the conditions in step S2 are met, Then execute steps S311 to S313 and steps S321 to S323.

Of course, the above alternative implementations, and between the alternative implementations and the preferred implementations can also be used in cross-coordination, so that new implementations can be combined to apply to more specific application scenarios.

It should be noted that the chiller provided in this embodiment also includes: a memory, a processor, and a control program of the chiller stored in the memory and operable on the processor, and the control program of the chiller is executed by the processor At this time, the control method of the water chiller in this embodiment is realized. Wherein, the above-mentioned processor may be a controller specially used to execute the method of the present invention, or may be a functional module or a functional unit of a general controller.

This embodiment also provides a computer-readable storage medium, the computer-readable storage medium stores the control program of the chiller, and when the program of the chiller is executed by the processor, the chiller in any of the above implementation modes is realized. control method.

Wherein, the aforementioned readable storage medium includes but is not limited to U disk, mobile hard disk, read-only memory (Read-Only Memory, ROM), random access memory (Random Access Memory, RAM), magnetic disk, optical disk, flash memory, easy Various media that can store program codes such as volatile memory, non-volatile memory, serial memory, parallel memory or registers, and processors include but not limited to CPLD/FPGA, DSP, ARM processor, MIPS processor, etc. These well-known structures are not shown in the figures in order to unnecessarily obscure the embodiments of the present disclosure.

The present invention can also be implemented as an apparatus or apparatus program (eg, PC program and PC program product) for performing a part or all of the methods described herein. Such a program for realizing the present invention may be stored on a PC-readable medium, or may be in the form of one or more signals. Such a signal may be downloaded from an Internet site, or provided on a carrier signal, or provided in any other form.

In addition, those skilled in the art will understand that although some embodiments described herein include some features included in other embodiments but not others, the combination of features of different embodiments means that it is protected by the present invention. range and form different embodiments. For example, in the claims of the present invention, any one of the claimed embodiments can be used in any combination.

So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings, however, those skilled in the art will easily understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to relevant technical features, and the technical solutions after these changes or substitutions will all fall within the protection scope of the present invention.

Claims

A control method for a chiller, characterized in that the control method comprises:

Obtain the actual outlet water temperature Tout of the chilled water of the chiller, and the historical outlet water temperature T1 before the set time period tb ;

Judging whether the water chiller satisfies the setting condition Tout< T0 and T1 - Tout≥K1 ; where T0 is the target outlet water temperature currently set, and k1 is the outlet water temperature within the set time period t b The normal change threshold of , and k 1 >0;

If the water chiller meets the setting conditions, re-determine the target outlet water temperature T x =T 0 +K 2 ; wherein, K 2 >0 and is a constant;

The chiller is controlled to perform cooling operation according to the re-determined target outlet water temperature Tx.
The control method according to claim 1, characterized in that, the actual inlet water temperature Tin of the chilled water of the chiller is also acquired;

After re-determining the target outlet water temperature Tx , also calculate the adjustment rate V of the target outlet water temperature of the chiller;

Among them, V=(T in -T out )*(T 1 -T out )*K 3 ; the unit of V is ℃/s, and K 3 is a constant;

The target outlet water temperature of the chiller is controlled to change from T 0 to T x at an adjustment speed V.
The control method according to claim 1 , wherein the step of "controlling the water chiller to perform cooling operation according to re-determining the target outlet water temperature Tx" comprises:

Control the compressor according to the preset mapping relationship between at least one parameter of the number of compressors to be turned on, the operating frequency, and the load energy of the chiller and the temperature difference (Tx- Tout ); and/or or,

The outdoor fan is controlled according to the preset mapping relationship between the turned-on number or the rotational speed of the outdoor fan of the chiller and the temperature difference (Tx- Tout ); and/or,

The cooling water pump is controlled according to the preset mapping relationship between the rotation speed of the cooling water pump of the chiller and the temperature difference (Tx- Tout ).
The control method according to claim 1 , wherein the step of "controlling the water chiller to perform cooling operation according to re-determining the target outlet water temperature Tx" comprises:

reducing at least one parameter of the number of compressors to be turned on, the operating frequency and the load energy of the chiller; and/or,

reducing the number or speed of the outdoor fan of the chiller; and/or,

Reduce the speed of the cooling water pump of the chiller.
The control method according to claim 1 , further comprising:

After the chiller is stopped and restarted, the target outlet water temperature is reset to T 0 , and the chiller is controlled to perform cooling operation according to the reset target outlet water temperature T 0 .
The control method according to claim 1, further comprising: before re-determining the target outlet water temperature:

Get the current time;

judging whether the current time is within the set fast load shedding time period;

If yes, then re-determine the target outlet water temperature.
The control method according to claim 1, further comprising: before re-determining the target outlet water temperature:

Obtain the current load rate of the chiller;

comparing the current load rate with a set load rate threshold;

If the current load rate is less than the load rate threshold, then re-determine the target outlet water temperature.
The control method according to claim 1, characterized in that, after judging whether the chiller meets the set condition, further comprising:

If the chiller does not satisfy the set condition, the chiller is controlled to maintain the currently set target outlet water temperature T0 and continue to operate.
The control method according to claim 1, wherein the set time period t should satisfy:

t b ≤ t 0 , where t 0 is the time required for the actual outlet water temperature T out to maintain the set shutdown temperature T t before the set control chiller shuts down.
The control method according to claim 9, characterized in that the constant K2 should satisfy: 0<K2≤3Tz, wherein Tz is the currently set shutdown temperature difference, and Tz=T0-Tt.