WO2020108170A1

WO2020108170A1 - Screw-type chiller, control method for same, and system

Info

Publication number: WO2020108170A1
Application number: PCT/CN2019/112397
Authority: WO
Inventors: 刘华; 龙忠铿; 罗炽亮; 王双亮; 吴宏择; 李莹
Original assignee: 珠海格力电器股份有限公司
Priority date: 2018-11-27
Filing date: 2019-10-22
Publication date: 2020-06-04
Also published as: CN109631376A; CN109631376B

Abstract

A screw-type chiller (100), a control method for the same, and a system. The screw-type chiller (100) comprises: a condenser (4); a cooling water flow path having cooling water therein flowing through the condenser (4); an evaporator (1); a chilled water flow path having chilled water therein flowing through the evaporator (1); a heat exchanger (7) for performing heat exchange between the output chilled water and the output cooling water; a valve (8) for adjusting flux of the cooling water entering the heat exchanger (7); a sensor assembly for detecting a cooling-water outlet temperature, a chilled-water inlet temperature, and a chilled-water outlet temperature; and a controller for controlling the valve (8) and/or the heat exchanger (7) according to the cooling-water outlet temperature and the chilled-water inlet temperature, so as to regulate the chilled-water outlet temperature and adjust an output load of the chiller (100). The heat exchanger (7) and the valve (8) are added to the chiller (100), such that the chilled-water outlet temperature can be adjusted by means of the output cooling water, and the chiller (100) can have a reduced output load range, even produce zero load output, without requiring a compressor (0) to be shut down, thereby resolving the technical issue in which existing screw-type chillers require a shutdown in order to achieve zero load output.

Description

Screw chiller and its control method and system

Related application

This disclosure requires the priority of the Chinese patent application filed on November 27, 2018, with the application number 201811438929.7 and titled "A Screw Chiller and Its Control Method and System", the entire content of which is hereby incorporated by reference.

Technical field

The present disclosure relates to the technical field of chiller control, in particular, to a screw chiller and its control method and system.

Background technique

On some special occasions, the screw chiller has strict requirements on the load output adjustment range. It needs to achieve 0%-100% load stepless adjustment, or when the terminal load changes and the chilled water temperature rises, the unit needs to increase the output load immediately.

At present, the load adjustment range of conventional screw chillers is 25%-100%, and the use of refrigerant bypass and other forms can only extend the load adjustment range to 10%-100%, and it is difficult to achieve 0%-100% load output regulation;

During the operation of the conventional screw chiller, the load output is generally adjusted by controlling the temperature of the frozen outlet water (also through the temperature of the frozen inlet water). When the temperature of the frozen outlet water is lower than the set value, the unit (compressor) starts to unload and reduce Load output, if the water temperature continues to decrease, the unit (compressor) continues to unload to the minimum load, and the unit (compressor) is turned off. When the temperature of the frozen effluent rises above the set temperature and the shutdown interval reaches a certain value, the unit restarts and outputs the load. When the terminal load change cannot be met, the chiller temperature rises immediately, and the unit immediately changes the requirement to increase the load output.

Therefore, a zero load output non-stop operation mode of the screw chiller needs to be proposed to meet the requirements of special occasions.

Application content

The embodiments of the present disclosure provide a screw chiller and its control method and system to solve the technical problem that the screw chiller cannot achieve zero-load output without stopping the machine.

An embodiment of the present disclosure provides a screw chiller including: a condenser; a cooling water flow path in which cooling water flows through the condenser; an evaporator; a chilled water flow path in which chilled water flows through the evaporator; Heater, which is used to exchange heat between the chilled water effluent of the chilled water flow path and the cooling water effluent of the cooling water flow path; a valve, which is used to adjust the flux of the cooling water into the heat exchanger; The sensor group is used for detecting the cooling water outlet temperature of the cooling water flowing out of the evaporator in the frozen water flow path, the chilled water inlet temperature and the chilled water outlet temperature of the chilled water flow path; the controller is used to The cooling water outlet temperature and the chilled water inlet temperature control the valve and/or heat exchanger to regulate the chilled water outlet temperature and adjust the output load of the chiller unit.

In one embodiment, the output load performance coefficient of the chiller unit ranges from 0% to 100%.

In one embodiment, the heat exchange amount of the heat exchanger is greater than or equal to a preset amount; wherein the preset amount is 25% of the output load of the chiller.

In one embodiment, the heat exchanger is a plate heat exchanger.

In one embodiment, the cooling water flow path includes a cooling water inlet pipe and a cooling water outlet pipe; the chilled water flow path includes a chilled water inlet pipe and a chilled water outlet pipe; the plate heat exchanger and the cooling water are respectively The bypass pipe of the water outlet pipe and the bypass pipe of the chilled water outlet pipe are connected, and the valve is provided at the bypass pipe where the cooling water outlet pipe is connected to the plate heat exchanger.

In one embodiment, the valve includes an electric valve and/or a solenoid valve.

According to another application of the present disclosure, there is also provided a chilled water system, which includes a plurality of chilled water units, and the plurality of chilled water units includes at least one of the screw chiller units.

According to another aspect of the application, there is also provided a control method for a screw chiller including: detecting the cooling water outlet temperature, chilled water inlet temperature, and chilled water outlet temperature of the spiral chiller, wherein, the The cooling water outlet temperature is the outlet water temperature of the cooling water in the cooling water flow path after passing through the condenser, and the chilled water inlet temperature is the inlet water temperature of the chilled water in the freezing water flow path before passing through the evaporator; the chilled water outlet temperature Is the outlet temperature of the chilled water in the chilled water flow path after passing through the evaporator; the valve and/or the heat exchanger are controlled according to the chilled water outlet temperature and the chilled water inlet temperature to use the chilled water outlet water to Adjust the temperature of the frozen outlet water and adjust the output load of the chiller.

In one embodiment, before the controlling the valve and/or the heat exchanger according to the cooling water outlet temperature and the chilled water inlet temperature, includes: obtaining the target output load performance coefficient of the chiller; When the target output load performance coefficient of the chiller meets a preset condition, the compressor is controlled to operate within a preset load range, where the preset load operating range is greater than or equal to the minimum rated operating load of the compressor.

In an embodiment, the controlling the valve and/or the heat exchanger according to the cooling water outlet temperature and the chilled water inlet temperature includes: if the acquired current output load performance coefficient of the chiller is less than the target Output load performance coefficient, control valve opening or increase valve opening to increase the heat exchange between the cooling water effluent and the chilled water effluent, and increase the temperature of the chilled water effluent; if the current output load of the chiller is obtained The coefficient of performance is greater than the target output load coefficient of performance, and the valve is closed or the valve opening is reduced to reduce the amount of heat exchange between the cooling water effluent and the chilled water effluent, so that the temperature of the chilled water effluent drops.

In one embodiment, the preset condition is that the target output load performance coefficient is greater than or equal to 0% and less than or equal to 25%.

In the above embodiment, the control method is to add a heat exchanger and a valve to the screw chiller, and use the screw chiller to cool the effluent to adjust the temperature of the frozen effluent. During this period, the compressor does not need to be shut down. When the temperature of the frozen outlet water reaches the set value, even if the output load of the compression operation reaches the minimum, the unit can reduce the output load range, and even achieve the zero load output of the unit, which broadens the load output range of the chiller unit and maintains the unit under zero load output Long-running. It solves the technical problem that the existing screw chiller cannot achieve zero load output without stopping. On the one hand, it can realize the stepless adjustment of the load output of the screw chiller in a large range, and on the other hand, it achieves zero load by means of non-stop. Output, and can be loaded quickly, the load response speed is fast, can meet the special occasions such as nuclear power and other applications for the chiller output load adjustment range is large, and the response to the load changes fast application requirements.

BRIEF DESCRIPTION

The drawings constituting a part of the present disclosure are used to provide a further understanding of the present disclosure. The exemplary embodiments and descriptions of the present disclosure are used to explain the present disclosure, and do not constitute an undue limitation on the present disclosure. In the drawings:

1 is a schematic diagram of an optional screw chiller in a zero-load output non-stop operation mode according to an embodiment of the present disclosure;

2 is a partial schematic diagram of an optional screw chiller in a zero-load output non-stop operation mode according to an embodiment of the present disclosure;

3 is a partial schematic diagram of a conventional screw chiller according to the prior art;

4 is a partial schematic view of an evaporator and a nozzle of a screw chiller according to an embodiment of the present disclosure;

FIG. 5 is a schematic flowchart of a control method of a screw chiller according to an embodiment of the present disclosure.

Reference mark:

In the picture: 100 is screw chiller; 0 is compressor; 1 is evaporator; 2 is chilled water inlet pipe; 3 is chilled water outlet pipe; 4 is condenser; 5 is cooling water inlet pipe; 6 is cooling water Outlet pipe; 7 for heat exchanger; 8 for electric valve; 9 for chilled water inlet temperature sensor; 10 for chilled water outlet temperature sensor; 11 for cooling water inlet temperature sensor; 12 for cooling water outlet temperature sensor.

detailed description

In order to make the purpose, technical solutions and advantages of the disclosure more clear, the disclosure will be further described in detail in conjunction with the embodiments and the drawings. Here, the exemplary embodiments of the present disclosure and the description thereof are used to explain the present disclosure, but are not intended to limit the present disclosure.

Considering that the existing screw chiller cannot achieve a wide range of stepless adjustment of the output load of the chiller, or it can not achieve zero load output without stopping the machine. In view of the root cause of the above technical problems, the present disclosure considers that a screw chiller with zero load output and non-stop operation mode can be used to adjust the temperature of the frozen outlet water through the heat exchanger and the frozen inlet water of the screw chiller. When the temperature reaches the set value, even if the output load of the compression operation reaches the minimum, the unit can reduce the output load range, and even realize the unit zero load output, so that the chiller unit load output (or output load performance coefficient) range reaches 0% ~ 100 %, and can keep the unit running for a long time under zero load output to meet the requirements of nuclear power and other special occasions. Therefore, it can solve the technical problem that the existing screw chiller can not achieve zero load output without stopping. On the one hand, it can realize the stepless adjustment of the load output of the screw chiller with a larger range, and on the other hand, it can be achieved by non-stop. The load has zero output and can be loaded quickly. The response speed of the load is fast, which can meet the application requirements of special occasions such as nuclear power and other applications.

Based on the above thinking, the embodiment of the present disclosure provides a screw chiller. FIG. 1 is a schematic diagram of an optional screw chiller in a zero-load output non-stop operation mode according to an embodiment of the present disclosure, such as As shown in FIG. 1, the screw chiller 100 includes: an evaporator 1, a condenser 4, a cooling water flow path (5 and 6 shown in FIG. 1), and a chilled water flow path (2 and 3 shown in FIG. 1) , Heat exchanger 7, valve 8, sensor group (9, 10, 12 shown in Figure 1), controller (not shown in Figure 1), where,

The cooling water flow path (5 and 6 shown in FIG. 1), and the cooling water in the cooling water flow path flows through the condenser 4;

The chilled water flow path (2 and 3 shown in FIG. 1), the chilled water in the chilled water flow path flows through the evaporator 1;

The heat exchanger 7 is used to exchange heat between the chilled water outlet of the chilled water flow path (3 shown in FIG. 1) and the chilled water outlet of the cooling water flow path (6 shown in FIG. 1);

Valve 8, which is used to adjust the flux of cooling water into the heat exchanger 7;

The sensor group is used to detect the cooling water outlet temperature of the cooling water flowing out of the evaporator in the chilled water flow path (as shown in FIG. 1 12), the chilled water inlet temperature of the chilled water flow path (as shown in FIG. 1 9) and The chilled water outlet temperature (10 as shown in FIG. 1); preferably, the above sensor group further includes a cooling water inlet temperature sensor 11 for detecting the cooling water inlet temperature. A controller (not shown in FIG. 1) is used to control the valve 8 and/or the heat exchanger 7 according to the cooling water outlet temperature and the chilled water inlet temperature to regulate the chilled water outlet temperature and adjust the output load of the chiller.

The screw chiller 100 is equipped with a heat exchanger 7 and a valve 8, and the screw chiller 100 is used to cool the effluent to adjust the temperature of the frozen effluent. During this period, the compressor 0 does not need to be shut down. When the temperature of the frozen outlet water reaches the set value, even if the output load of the compression operation reaches the minimum, the unit can reduce the output load range, and even realize the unit's zero load output, so that the chiller unit's load output range increases and can be maintained at zero load output The unit has been running for a long time. It solves the technical problem that the existing screw chiller cannot achieve zero load output without stopping. On the one hand, it can realize the stepless adjustment of the load output of the screw chiller in a large range, and on the other hand, it achieves zero load by means of non-stop. Output, and can be loaded quickly, the load response speed is fast, can meet the special occasions such as nuclear power and other applications for the chiller output load adjustment range is large, and the response to the load changes fast application requirements.

In the above embodiment, the output load performance coefficient of the chiller is in the range of 0% to 100%.

Through the non-stop operation mode of the zero load output of the screw chiller, on the one hand, it can realize the stepless adjustment of the load output of the screw chiller from 0% to 100%. On the other hand, the zero output of the load is achieved by the non-stop mode, and it can be quickly loaded. The load response speed is fast, which can meet the application requirements of the special occasions such as nuclear power and the large adjustment range for the output load requirements of the chiller, and the fast response to load changes.

In a preferred embodiment, the cooling water flow path includes a cooling water inlet pipe 5 and a cooling water outlet pipe 6;

The chilled water flow path includes chilled water inlet pipe 2 and chilled water outlet pipe 3;

The plate heat exchanger 7 is connected to the bypass pipe of the cooling water outlet pipe 6 and the bypass pipe of the chilled water outlet pipe 3,

The valve 8 is provided at the bypass pipe connecting the cooling water outlet pipe and the plate heat exchanger.

Preferably, the heat exchanger in the above embodiment may be a plate heat exchanger. The plate heat exchanger can change the temperature of the chilled water effluent that just flows through the evaporator. By exchanging heat between the chilled water effluent and the cooling water effluent that flows out of the condenser, the temperature of the chilled water effluent when it flows out of the chilled water outlet pipe Becomes higher, so that the actual output load can be adjusted, so that the actual output load can be smaller than the general minimum limit value, or even reach zero load output, and the compressor at this time can still be operated with a smaller load without stopping the machine. The output load reaches zero without stopping the compressor.

Through the above embodiment, the bypass amount of the bypass pipe of the cooling water outlet pipe 6 can be controlled by the valve 8, and the bypass amount can be controlled by controlling the opening and closing of the valve 8 or adjusting the opening degree of the valve 8 to control the cooling water outlet and The heat exchange amount of the chilled water effluent makes the chilled water effluent adjusted to an appropriate temperature according to the actual situation, thereby regulating the chilled water effluent temperature to reach a preset value, and finally adjusting the actual load output of the chiller to meet the needs of special occasions such as nuclear power , The regulation range is larger, and the stepless adjustment of the output load performance coefficient is 0% to 100%.

FIG. 2 is a partial schematic diagram of an optional screw chiller in a zero-load output non-stop operation mode according to an embodiment of the present disclosure. As shown in FIG. 2, for the chiller, the actual output load can be The flow rate of chilled water and the temperature difference between the inlet and outlet of chilled water are calculated as follows:

Q＝cm(t _{chill_in} -t _{chill_out} )

Among them: Q is the actual output load size; c is the specific heat of the chilled water, which can be regarded as a certain value; m is the mass flow rate of the chilled water; t _{chill_in} is the inlet temperature of the chilled water, installed by the 2 nozzles in FIG. 2 Measured by the chilled water inlet temperature sensor 9; t _{chill_out} is the chilled water outlet temperature, measured by the chilled water outlet temperature sensor 10 installed at the 3 nozzle in FIG. 2.

Compared with the conventional screw chiller, a chiller adopting a zero-load output non-stop operation mode of the screw chiller adds part 7 (and takeover) and part 8 in the drawing, and the component 7 according to the heat exchange capacity is not less than the chiller Select 25% output load. Due to the limitation of the compressor, the output load of the conventional screw chiller cannot be reduced to a particularly low level (generally at least about 25%). Therefore, when the unit is in operation, there will definitely be a load output, and the temperature of the frozen outlet water is lower than the temperature of the frozen inlet water. t _{chill_in} -t _{chill_out} > 0.

Figure 3 is a partial schematic view of a conventional screw chiller according to the prior art. As shown in Figure 3, when the chiller needs to reduce the output load to below 25% or even 0%, the compressor can be operated according to its minimum The minimum load operation is designed. At this time, for the evaporator 1, it will still be cooled according to the compressor output load. The temperature of the chilled water at the outlet of the evaporator 1, that is, the inlet of the component 3, will be lower than the chilled inlet temperature of the unit. , At this time t _3' <t _2' = t _{chill_in} , the compressor output load Q _com at this time is:

Q _com =cm(t _{chill_in} -t _3' )

_t _{3 '≤t} chill_out

4 is a partial schematic view of an evaporator and a nozzle of a screw chiller according to an embodiment of the present disclosure. As shown in FIG. 4, according to a valve 8 (or cooling water outlet temperature sensor 12) and chilled water inlet temperature sensor 9 The detected temperature, by controlling the opening of the valve 8 and using the heat exchanger 7, can adjust (lift) the chilled water at the outlet of the chilled water outlet pipe 3 by adjusting the amount of cooling water bypass to change the amount of heat transfer Water temperature t _{chill_out} . With the increase of the opening of valve 8, the chilled water outlet temperature t _{chill_out} gradually increases (at this time, the excessive rise of t _{chill_out} should be avoided to cause the unit to load), and the chilled water inlet and outlet temperature difference t _{chill_in} -t _{chill_out} gradually decreases; When the opening degree of the component 8 increases to a certain value, the temperature difference between the chilled water inlet and outlet water t _{chill_in} -t _{chill_out} =0, then the output load of the chiller can reach 0%.

Therefore, through this method, the chiller can realize the stepless adjustment of the output load from 0% to 100%, and the compressor can also operate safely according to its designed minimum load output.

In an optional embodiment, the heat exchange amount of the heat exchanger is greater than or equal to a preset amount; wherein the preset amount is 25% of the output load of the chiller. That is, the heat exchanger 7 is selected according to the heat exchange capacity not less than 25% of the output load of the chiller. Choosing such a heat exchanger can effectively and quickly exchange the cooling water effluent of the condenser 4 and the chilled water evaporator 1 of the evaporator 1, and when the output load performance coefficient of the chiller needs to be adjusted to 25% or less, change The heat exchanger can achieve a heat exchange amount greater than 25% of the output load of the chiller. When the compressor operating load is high, the temperature of the chilled water outlet can be adjusted to a higher temperature. At this time, the compressor output load can be reduced In this way, it can realize the stepless adjustment of the output load from 0% to 100% without shutting down the unit.

In an alternative embodiment, the valve includes an electric valve, a solenoid valve, or a combination of both.

When the valve is an electric valve, the controller can adjust the opening and closing of the valve, and can also accurately adjust its opening degree, which can accurately control the load output of the chiller; and the valve using a solenoid valve can also be controlled by controlling its opening and closing. , To achieve the use of cooling water effluent to adjust the temperature of the chilled water effluent, thereby adjusting the load output of the chiller.

In an application scenario, after the solenoid valve is used for the valve 8, since the solenoid valve can only be controlled to open and stop, the precise adjustment of the cooling water bypass volume cannot be achieved, and therefore the precise adjustment of the chilled water outlet temperature cannot be achieved.

When the chiller needs to adjust the output load to less than 25%, the compressor runs at the designed minimum load, and the valve 8 is energized, the valve 8 is opened, the temperature of the chilled water outlet will rise to a certain extent, the compressor will load, increase the load output .

When the valve 8 is closed, when the unit output load is 25%, the unit output load is equal to the compressor output load.

Q _25% = cm(t _{chill_in} -t _{chill_out} )

t _3' = t _{chill_out}

When component 8 is turned on, when the unit output load is at 25%,

t _3' ＜t _{chill_out}

That is, the output load of the compressor at this time is not at the minimum value of its design operation,

Q _com =cm(t _{chill_in} -t _3' )>Q _25%

At this time, the output load of the unit can be reduced by reducing the operating load of the compressor, and the stepless adjustment of the output load of 0% to 100% of the unit without shutdown.

Based on the same application concept, an embodiment of the present disclosure also provides a chilled water system. The chilled water system includes multiple chillers, and the multiple chillers include at least one screw chiller as described above.

In a chilled water system composed of multiple chillers, the above method can also be used to achieve zero-load load output without shutdown, and to achieve stepless adjustment of the unit load performance coefficient from 0% to 100%.

Based on the same application concept, a control method for a screw chiller is also provided in an embodiment of the present disclosure. FIG. 5 is a schematic flowchart of a control method for a screw chiller according to an embodiment of the present disclosure, as shown in FIG. 5 As shown, the control method includes:

S101: Detect the cooling water outlet temperature, chilled water inlet temperature, and chilled water outlet temperature of the spiral chiller,

Among them, the outlet temperature of the cooling water is the outlet temperature of the cooling water in the cooling water flow path after passing through the condenser, and the inlet temperature of the chilled water is the inlet temperature of the chilled water in the chilled water flow path before passing through the evaporator; the outlet temperature of the chilled water is freezing The outlet temperature of the chilled water in the water flow path after passing through the evaporator;

S103: Control the valve and/or the heat exchanger according to the cooling water outlet temperature and the chilled water inlet temperature to adjust the chilled outlet temperature using the cooling water outlet and adjust the output load of the chiller.

The screw chiller 100 is equipped with a heat exchanger 7 and a valve 8, and the screw chiller 100 is used to cool the effluent to adjust the temperature of the frozen effluent. During this period, the compressor 0 does not need to be shut down. When the temperature of the frozen outlet water reaches the set value, even if the output load of the compression operation reaches the minimum, the unit can reduce the output load range, and even achieve zero load output of the unit, so that the chiller unit load output range reaches 0% to 100%, and at zero load The output can keep the unit running for a long time. It solves the technical problem that the existing screw chiller cannot achieve zero load output without stopping. On the one hand, it can realize the stepless adjustment of the load output of the screw chiller in a large range, and on the other hand, it achieves zero load by means of non-stop. Output, and can be loaded quickly, the load response speed is fast, can meet the special occasions such as nuclear power and other applications for the chiller output load adjustment range is large, and the response to the load changes fast application requirements.

In an optional embodiment, in the above step S101, before controlling the valve and/or the heat exchanger according to the cooling water outlet temperature and the chilled water inlet temperature, the control method includes:

S101a, obtaining the target output load performance coefficient of the chiller;

S101b. When the target output load performance coefficient of the chiller meets the preset condition, the compressor is controlled to operate according to the preset load range, where the preset load operating range is greater than or equal to the minimum rated operating load of the compressor.

Preferably, the preset condition is that the target output load performance coefficient of the chiller is greater than or equal to 0% and less than or equal to 25%.

In the above step S101, controlling the valve and/or the heat exchanger according to the cooling water outlet temperature and the chilled water inlet temperature includes:

If the current output load performance coefficient of the obtained chiller is less than the target output load performance coefficient, control the valve to open or increase the valve opening to increase the amount of heat exchange between the cooling water effluent and the chilled water effluent, so that the chilled water effluent temperature rises;

If the current output load performance coefficient of the obtained chiller is greater than the target output load performance coefficient, control the valve to close or reduce the opening of the valve to reduce the amount of heat exchange between the cooling water effluent and the chilled water effluent, so that the chilled water effluent temperature decline.

Through the above embodiments of the present disclosure, the following technical effects can be achieved:

1. It can widen the range of the load output of the conventional screw chiller from 25% to 100%, and realize the stepless adjustment of the output load of the chiller from 0% to 100%;

2. Changed the way that the conventional screw unit must be stopped when it achieves zero load output. By this way, the chiller can be stopped without stopping, and the unit load zero output can be achieved. When the terminal load changes, the output load can be quickly loaded.

When the chiller needs to adjust the output load to below 25%, the compressor runs at the designed minimum load, the valve 8 is energized, the valve is opened, the chilled water outlet temperature t _{chill_out} will rise to a certain extent, the compressor will load, increase the load Output.

Q _25% = cm(t _{chill_in} -t _{chill_out} )

t _3' = t _{chill_out}

When the valve 8 is opened, when the output load of the unit is at 25%,

t _3' ＜t _{chill_out}

Q _com =cm(t _{chill_in} -t _3' )>Q _25%

Through the screw chiller and its control method and system in the above embodiments, the following technical effects can be achieved:

2. Changed the way that the conventional screw unit must be stopped when it achieves zero load output. By this way, the chiller can be stopped without stopping, and the unit load can be zero output. When the terminal load changes, the output load can be quickly loaded.

The above is only the preferred embodiments of the present disclosure and is not intended to limit the present disclosure. For those skilled in the art, the embodiments of the present disclosure may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this disclosure shall be included in the protection scope of this disclosure.

Claims

A screw-type water chiller is characterized by comprising:

Condenser

A cooling water flow path, wherein the cooling water flows through the condenser;

Evaporator;

A chilled water flow path, where chilled water flows through the evaporator;

A heat exchanger, which is used to exchange heat between the chilled water effluent of the chilled water flow path and the cooling water effluent of the cooling water flow path;

A valve for regulating the flux of the cooling water into the heat exchanger;

The sensor group is used for detecting the cooling water outlet temperature of the cooling water flowing out of the evaporator in the frozen water flow path, the chilled water inlet temperature and the chilled water outlet temperature of the chilled water flow path;

A controller for controlling at least one of the valve and the heat exchanger according to the cooling water outlet temperature and the chilled water inlet temperature to adjust the chilled water outlet temperature and adjust the chiller unit temperature Output load.
The screw chiller of claim 1, wherein the output load performance coefficient of the chiller is in the range of 0% to 100%.
The screw chiller according to claim 1, wherein the heat exchange amount of the heat exchanger is greater than or equal to a preset amount; wherein the preset amount is 25% of the output load of the chiller.
The screw chiller according to claim 1, wherein the heat exchanger is a plate heat exchanger.
The screw chiller according to claim 4, characterized in that

The cooling water flow path includes a cooling water inlet pipe and a cooling water outlet pipe;

The frozen water flow path includes a chilled water inlet pipe and a chilled water outlet pipe;

The plate heat exchanger is respectively connected to the bypass pipe of the cooling water outlet pipe and the bypass pipe of the chilled water outlet pipe,

The valve is provided at a bypass pipe connecting the cooling water outlet pipe and the plate heat exchanger.
The screw chiller according to claim 1, wherein the valve includes at least one of an electric valve and a solenoid valve.
A chiller system includes a plurality of chillers, and the plurality of chillers includes at least one screw chiller according to any one of claims 1 to 6.
A control method for a screw chiller is characterized by including:

Detect the cooling water outlet temperature, chilled water inlet temperature, and chilled water outlet temperature of the spiral chiller,

Wherein, the cooling water outlet temperature is the outlet water temperature after the cooling water in the cooling water flow path passes through the condenser, and the chilled water inlet temperature is the inlet water temperature before the chilled water in the freezing water flow path passes through the evaporator; The chilled water outlet temperature is the outlet temperature of the chilled water in the chilled water flow path after passing through the evaporator;

According to at least one of the cooling water outlet temperature, the chilled water inlet temperature control valve and the heat exchanger, to use the cooling water outlet water to adjust the frozen outlet water temperature and adjust the output load of the chiller .
The control method according to claim 8, wherein before controlling at least one of the cooling water outlet temperature and the chilled water inlet temperature, the control method further comprises:

Obtaining the target output load performance coefficient of the chiller;

When the target output load performance coefficient of the chiller meets a preset condition, the compressor is controlled to operate within a preset load range, where the preset load operating range is greater than or equal to the minimum rated operating load of the compressor.
The control method according to claim 9, wherein the at least one of the control valve and the heat exchanger according to the cooling water outlet temperature and the chilled water inlet temperature includes:

If the acquired current output load performance coefficient of the chiller is less than the target output load performance coefficient, control the valve to open or increase the valve opening to increase the heat exchange between the cooling water effluent and the chilled water effluent, so that The temperature of the chilled water outlet rises;

If the acquired current output load performance coefficient of the chiller is greater than the target output load performance coefficient, control the valve to close or reduce the opening of the valve to reduce the amount of heat exchange between the cooling water outlet water and the chilled water outlet To lower the temperature of the chilled water outlet.
The control method according to claim 9, wherein the preset condition is that the target output load performance coefficient is greater than or equal to 0% and less than or equal to 25%.