CN109631376B - Screw type water chilling unit and control method and system thereof - Google Patents
Screw type water chilling unit and control method and system thereof Download PDFInfo
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- CN109631376B CN109631376B CN201811438929.7A CN201811438929A CN109631376B CN 109631376 B CN109631376 B CN 109631376B CN 201811438929 A CN201811438929 A CN 201811438929A CN 109631376 B CN109631376 B CN 109631376B
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B1/00—Compression machines, plants or systems with non-reversible cycle
- F25B1/04—Compression machines, plants or systems with non-reversible cycle with compressor of rotary type
- F25B1/047—Compression machines, plants or systems with non-reversible cycle with compressor of rotary type of screw type
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B49/00—Arrangement or mounting of control or safety devices
- F25B49/02—Arrangement or mounting of control or safety devices for compression type machines, plants or systems
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Abstract
The invention provides a screw type water chilling unit and a control method and system thereof. This screw cooling water set includes: 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; the heat exchanger is used for exchanging heat between the chilled water outlet water and the cooling water outlet water; the valve is used for adjusting the flux of cooling water entering the heat exchanger; the sensor group is used for detecting the outlet water temperature of the cooling water and the inlet and outlet water temperatures of the chilled water; the controller is used for controlling the valve and/or the heat exchanger according to the outlet water temperature of the cooling water and the inlet water temperature of the chilled water so as to regulate and control the outlet water temperature of the chilled water and regulate the output load of the water chilling unit. The heat exchanger and the valve are additionally arranged in the water chilling unit, the chilled water outlet temperature is adjusted by utilizing the chilled water outlet, the compressor does not need to be stopped, the unit can also reduce the output load range, even the zero load output, and the technical problem that the existing screw water chilling unit cannot realize the zero load output under the condition of no stop is solved.
Description
Technical Field
The invention relates to the technical field of water chilling unit control, in particular to a screw type water chilling unit and a control method and system thereof.
Background
In some special occasions, the requirement of the screw water chilling unit on the load output regulation range is strict, stepless regulation of 0-100% load needs to be realized, or the output load needs to be increased immediately after the tail end load changes and the temperature of the chilled water rises.
At present, the load adjusting range of the conventional screw type water chilling unit is 25-100%, the load adjusting range can be expanded to 10-100% only by adopting the forms of refrigerant bypass and the like, and the load output adjustment of 0-100% is difficult to realize;
in the operation process of the conventional screw type water chilling unit, the load output is generally adjusted by controlling the temperature of the freezing outlet water (or the temperature of the freezing inlet water), when the temperature of the freezing outlet water is lower than a set value, the unit (compressor) starts to unload, the load output is reduced, if the temperature of the freezing outlet water is continuously reduced, the unit (compressor) is continuously unloaded to the minimum load, and the unit (compressor) is shut down. When the temperature of the frozen outlet water rises above the set temperature and the shutdown interval reaches a certain value, the unit is restarted and the load is output. When the load at the tail end is changed and the temperature of the chilled water rises, the unit immediately changes the requirement of increasing the load output.
Therefore, a zero-load output non-stop operation mode of the screw type water chilling unit is to be provided to meet the use requirements of special occasions.
Disclosure of Invention
The embodiment of the invention provides a screw type water chilling unit and a control method and a system thereof, and aims to solve the technical problem that the existing screw type water chilling unit cannot realize zero load output under the condition of no shutdown.
The embodiment of the invention provides a screw type water chilling unit, which comprises: 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; a heat exchanger for exchanging heat between the chilled water outlet of the chilled water flow path and the cooling water outlet of the cooling water flow path; a valve for regulating the flux of the cooling water into the heat exchanger; a sensor group for detecting the cooling water outlet temperature of the cooling water flowing out of the evaporator in the cooling water flow path, the cooling water inlet temperature and the cooling water outlet temperature of the cooling water flow path; and the controller is used for controlling the valve and/or the heat exchanger according to the outlet water temperature of the cooling water and the inlet water temperature of the chilled water so as to regulate and control the outlet water temperature of the chilled water and regulate the output load of the water chilling unit.
In one embodiment, the output load performance coefficient of the chiller is in a range of 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 quantity is 25% of the output load of the water chilling unit.
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 comprises a chilled water inlet pipe and a chilled water outlet pipe; the plate heat exchanger is respectively connected with a bypass pipeline of the cooling water outlet pipe and a bypass pipeline of the chilled water outlet pipe, and the valve is arranged at the bypass pipeline where the cooling water outlet pipeline is connected with the plate heat exchanger.
In one embodiment, the valve comprises an electric valve and/or a solenoid valve.
According to another invention, the invention also provides a water cooling system which comprises a plurality of water cooling units, wherein at least one screw type water cooling unit is arranged in the plurality of water cooling units.
According to another aspect of the invention, there is also provided a control method for a screw chiller, comprising: detecting the outlet water temperature of cooling water, the inlet water temperature of chilled water and the outlet water temperature of the chilled water of the spiral water chilling unit, wherein the outlet water temperature of the cooling water is the outlet water temperature of the cooling water in the cooling water flow path after the cooling water flows through the condenser, and the inlet water temperature of the chilled water is the inlet water temperature of the chilled water in the chilled water flow path before the chilled water flows through the evaporator; the chilled water outlet temperature is the outlet temperature of the chilled water in the chilled water flow path after the chilled water flows through the evaporator; and controlling a valve and/or a heat exchanger according to the outlet water temperature of the cooling water and the inlet water temperature of the chilled water so as to adjust the chilled outlet water temperature by utilizing the outlet water of the cooling water and adjust the output load of the water chilling unit.
In one embodiment, before the controlling the valve and/or the heat exchanger according to the outlet water temperature of the cooling water and the inlet water temperature of the chilled water, the method comprises the following steps: acquiring a target output load performance coefficient of the water chilling unit; and when the target output load performance coefficient of the water chilling unit meets a preset condition, controlling the compressor to operate according to a preset load range, wherein the preset load operation range is greater than or equal to the minimum rated operation load of the compressor.
In one embodiment, the controlling of the valve and/or the heat exchanger according to the outlet temperature of the cooling water, the inlet temperature of the chilled water comprises: if the obtained current output load performance coefficient of the water chilling unit is smaller than the target output load performance coefficient, controlling a valve to be opened or increasing the opening of the valve so as to increase the heat exchange quantity between the cooling water outlet and the chilled water outlet and increase the temperature of the chilled water outlet; and if the obtained current output load performance coefficient of the water chilling unit is greater than the target output load performance coefficient, controlling a valve to be closed or reducing the opening of the valve so as to reduce the heat exchange quantity between the cooling water outlet and the chilled water outlet and reduce the temperature of the chilled water outlet.
In one embodiment, the preset condition is that the target output load performance coefficient is 0% or more and 25% or less.
In the above embodiment, the control method adjusts the chilled outlet water temperature by adding a heat exchanger and a valve in the screw chiller and using the screw chiller to cool the outlet water, during which time the compressor does not need to be shut down. When the temperature of the frozen water reaches a set value, even if the output load of the compression operation reaches the minimum, the unit can reduce the output load range, even realize the zero load output of the unit, widen the load output range of the water chilling unit, and keep the unit to operate for a long time under the zero load output. The technical problem that the existing screw type water chilling unit cannot realize zero-load output under the condition of no shutdown is solved, on one hand, stepless adjustment of the screw type water chilling unit in a large range of load output can be realized, on the other hand, zero-load output is realized in a non-shutdown mode, and the water chilling unit can be loaded quickly, has high load response speed, and can meet the application requirements of nuclear power and other special occasions on large adjustment range of output load requirements of the water chilling unit and high load change response.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an embodiment of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:
FIG. 1 is a schematic diagram of an alternative screw chiller in a zero load output non-stop mode of operation according to an embodiment of the present invention;
FIG. 2 is a partial schematic view of an alternative screw chiller in a zero load output non-stop mode of operation in accordance with an embodiment of the present invention;
FIG. 3 is a partial schematic view of a conventional screw chiller according to the prior art;
FIG. 4 is a partial schematic view of an evaporator and a connection pipe of a screw chiller according to an embodiment of the present invention;
fig. 5 is a flow chart of a control method of a screw chiller according to an embodiment of the invention.
Reference numerals:
in the figure: 100 is a screw type water chilling unit; 0 is a compressor; 1 is an evaporator; 2 is a chilled water inlet pipe; 3 is a chilled water outlet pipe; 4 is a condenser; 5 is a cooling water inlet pipe; 6 is a cooling water outlet pipe; 7 is a heat exchanger; 8 is an electric valve; 9 is a chilled water inlet temperature sensor; 10 is a chilled water outlet temperature sensor; 11 is a cooling water inlet temperature sensor; and 12 is a cooling water outlet temperature sensor.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the following embodiments and accompanying drawings. The exemplary embodiments and descriptions of the present invention are provided to explain the present invention, but not to limit the present invention.
The existing screw type water chilling unit can not realize stepless regulation of the output load of the water chilling unit in a larger range or can not realize zero load output under the condition of no shutdown. Aiming at the root cause of the technical problems, the invention considers that a screw type water chilling unit zero load output non-stop operation mode can be adopted, the freezing water inlet of the screw type water chilling unit is utilized to adjust the freezing water outlet temperature through a heat exchanger, when the freezing water outlet temperature reaches a set value, even if the output load of the compression operation reaches the minimum, the unit can reduce the output load range, even realize the zero load output of the unit, the load output (or called as the output load performance coefficient) range of the water chilling unit reaches 0-100 percent, and the unit can be kept to operate for a long time under the zero load output, thereby meeting the use requirements of special occasions such as nuclear power and the like. Therefore, the technical problem that the existing screw type water chilling unit cannot realize zero load output under the condition of no shutdown can be solved, on one hand, stepless adjustment of the screw type water chilling unit in a large load output range can be realized, on the other hand, zero load output is realized in a non-shutdown mode, and the water chilling unit can be loaded quickly, has high load response speed, and can meet the application requirements of nuclear power and other special occasions on large adjustment range of output load requirements of the water chilling unit and high load change response.
Based on the above thought, the present application 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 invention, and as shown in fig. 1, the screw chiller 100 includes: evaporator 1, condenser 4, cooling water flow paths (5 and 6 as shown in fig. 1), chilled water flow paths (2 and 3 as shown in fig. 1), heat exchanger 7, valve 8, sensor sets (9, 10, 12 as shown in fig. 1), controller (not shown in fig. 1), wherein,
a cooling water flow path (5 and 6 shown in fig. 1), the cooling water in the cooling water flow path flowing through the condenser 4;
a chilled water flow path (2 and 3 shown in fig. 1) in which chilled water flows through the evaporator 1;
a heat exchanger 7 for exchanging heat between the chilled water outflow (3 shown in fig. 1) of the chilled water flow path and the cooling water outflow (6 shown in fig. 1) of the cooling water flow path;
a valve 8 for regulating the flux of cooling water into the heat exchanger 7;
a sensor group for detecting a cooling water outlet temperature (12 shown in fig. 1) at which cooling water in the cooling water flow path flows out of the evaporator, a cooling water inlet temperature (9 shown in fig. 1) and a cooling water outlet temperature (10 shown in fig. 1) of the cooling water flow path; preferably, the sensor group further includes a cooling water inlet temperature sensor 11 for detecting the inlet temperature of the cooling water. And the controller (not shown in fig. 1) is used for controlling the valve 8 and/or the heat exchanger 7 according to the outlet water temperature of the cooling water and the inlet water temperature of the chilled water so as to regulate and control the outlet water temperature of the chilled water and adjust the output load of the water chilling unit.
The screw chiller 100 adjusts the temperature of the chilled water by adding the heat exchanger 7 and the valve 8 and cooling the water output by the screw chiller 100, during which the compressor 0 does not need to be stopped. When the temperature of the frozen water reaches a set value, even if the output load of the compression operation reaches the minimum, the unit can reduce the output load range, even realize the zero load output of the unit, increase the load output range of the water chilling unit, and keep the unit to operate for a long time under the zero load output. The technical problem that the existing screw type water chilling unit cannot realize zero-load output under the condition of no shutdown is solved, on one hand, stepless adjustment of the screw type water chilling unit in a large range of load output can be realized, on the other hand, zero-load output is realized in a non-shutdown mode, and the water chilling unit can be loaded quickly, has high load response speed, and can meet the application requirements of nuclear power and other special occasions on large adjustment range of output load requirements of the water chilling unit and high load change response.
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 zero load output of the screw type water chilling unit, on one hand, stepless adjustment of 0% -100% of load output of the screw type water chilling unit can be achieved, on the other hand, zero load output is achieved through the non-stop mode, rapid loading can be achieved, the load response speed is high, and the application requirements of special occasions such as nuclear power and the like on large adjustment range of output load requirements of the water chilling unit and rapid load change response can be met.
In a preferred embodiment, the cooling water flow path comprises a cooling water inlet pipe 5 and a cooling water outlet pipe 6;
the chilled water flow path comprises a chilled water inlet pipe 2 and a chilled water outlet pipe 3;
the plate heat exchanger 7 is respectively connected with a bypass pipeline of the cooling water outlet pipe 6 and a bypass pipeline of the chilled water outlet pipe 3,
the valve 8 is arranged at the bypass pipeline where the cooling water outlet pipeline is connected with the plate heat exchanger.
The heat exchanger in the above embodiment may preferably be a plate heat exchanger. The plate heat exchanger can change the temperature of the outlet chilled water which just flows through the evaporator, and the outlet chilled water exchanges heat with the outlet cooling water flowing out of the condenser, so that the temperature of the outlet chilled water is increased when the outlet chilled water flows out of the outlet chilled water pipe, the actual output load can be adjusted, the actual output load can be smaller than the common minimum limit value and even reach zero load output, the compressor at the moment can still run with smaller load and does not need to be stopped, and the output load reaches zero under the condition that the compressor does not stop.
Through the embodiment, the bypass quantity of the bypass pipeline of the cooling water outlet pipe 6 can be controlled through the valve 8, the bypass quantity is controlled by controlling the opening and closing of the valve 8 or adjusting the opening degree of the valve 8, so that the heat exchange quantity of the cooling water outlet water and the chilled water outlet water is controlled, the chilled water outlet water is adjusted to be at a proper temperature according to actual conditions, the chilled water outlet water temperature is adjusted to reach a preset value, the actual load output of a water chilling unit is finally adjusted, the requirements of special occasions such as nuclear power and the like are met, the adjusting range is larger, and stepless adjustment of the output load performance coefficient of 0-100% is realized.
Fig. 2 is a partial schematic diagram of an alternative screw chiller in a zero-load-output non-stop operation mode according to an embodiment of the present invention, and as shown in fig. 2, for the chiller, the actual output load can be calculated from the chilled water flow and the chilled water inlet/outlet temperature difference:
Q＝cm(tchill_in-tchill_out)
wherein: q is the actual output load size; c is the specific heat of the chilled water and can be regarded as a certain value; m is the mass flow of the chilled water; t is tchill_inThe temperature of the inlet chilled water is measured by a chilled water inlet temperature sensor 9 arranged at the pipe orifice 2 in the attached figure 2; t is tchill_outThe temperature of the outlet water of the chilled water is shown by the attached figure2, a chilled water outlet temperature sensor 10 arranged at the pipe orifice 3 is used for measuring.
Compared with a conventional screw type water chilling unit, the water chilling unit adopting the screw type water chilling unit zero-load output non-stop operation mode is additionally provided with a part 7 (and a connecting pipe) and a part 8 in the attached drawing, and the part 7 is selected according to the condition that the heat exchange quantity is not less than 25% of the output load of the water chilling unit. The output load of the conventional screw type water chilling unit cannot be reduced to a special low (generally about 25 percent at the lowest) due to the limitation of a compressor, so that when the unit is operated, the load output is ensured, the temperature of the frozen outlet water is lower than that of the frozen inlet water, tchill_in-tchill_out＞0。
FIG. 3 is a partial schematic view of a conventional screw chiller according to the prior art, as shown in FIG. 3, when the chiller needs to reduce the output load below 25% or even 0% operation, the compressor can be operated at its lowest design minimum load, and at this time, for the evaporator 1, it still performs cooling according to the output load of the compressor, and at the chilled water outlet of the evaporator 1, i.e., at the inlet of the unit 3, the chilled water temperature is lower than the chilled water inlet temperature of the chiller, at this time, t3'＜t2'＝tchill_inAt this time, the compressor outputs a load QcomThe size is as follows:
Qcom＝cm(tchill_in-t3')
t3'≤tchill_out
fig. 4 is a partial schematic view of an evaporator and a connection pipe of a screw chiller according to an embodiment of the present invention, as shown in fig. 4, the temperature t of chilled water at the outlet of the chilled water outlet pipe 3 can be adjusted (increased) by controlling the opening of the valve 8 according to the temperatures detected by the valve 8 (or the chilled water outlet temperature sensor 12) and the chilled water inlet temperature sensor 9, and by using the heat exchanger 7, by adjusting the bypass amount of the chilled water to change the amount of heat exchangechill_out. Along with the increase of the opening degree of the valve 8, the temperature t of the outlet water of the chilled waterchill_outGradually increase (at this time t should be avoided)chill_outToo high of a rise, causing unit loading), the difference t between the inlet and outlet water temperatures of the chilled waterchill_in-tchill_outGradually decrease; when the opening of the component 8 is increased to a certain value, the temperature difference t between the inlet water and the outlet water of the chilled waterchill_in-tchill_outWhen the output load of the water chilling unit is equal to 0%, the output load of the water chilling unit can reach 0%.
Therefore, by the method, the water chilling unit can realize stepless regulation of 0-100% of output load, and the compressor can safely operate according to the 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 quantity is 25% of the output load of the water chilling unit. Namely, the heat exchanger 7 is selected according to the heat exchange quantity not less than 25% of the output load of the water chilling unit. By selecting the heat exchanger, heat exchange between cooling water outlet of the condenser 4 and chilled water outlet of the evaporator 1 can be effectively and quickly realized, when the output load performance coefficient of the water chilling unit needs to be adjusted to be less than or equal to 25%, the heat exchanger can realize heat exchange with the heat exchange quantity being more than 25% of the output load of the water chilling unit, when the operation load of the compressor is higher, the temperature of the chilled water outlet can be adjusted to be higher, and at the moment, stepless adjustment of 0% -100% of the output load of the unit under the condition of no shutdown can be realized by reducing the output load of the compressor.
In an alternative embodiment, the valve comprises an electrically operated 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 the opening of the valve, so that the load output of the water chilling unit can be accurately controlled; the valve of the electromagnetic valve can be controlled to open and close to adjust the outlet water temperature of the chilled water by utilizing the outlet water of the cooling water, so that the load output of the water chilling unit is adjusted.
In an application scenario, after the valve 8 adopts the electromagnetic valve, the electromagnetic valve can only be controlled to be turned on and off, and the accurate adjustment of the bypass flux of the cooling water cannot be realized, so that the accurate adjustment of the outlet water temperature of the chilled water cannot be realized.
When the output load of the water chilling unit needs to be adjusted to be below 25%, the compressor operates according to the designed minimum load, the valve 8 is electrified, the valve 8 is opened, the outlet water temperature of the chilled water rises to a certain degree, the compressor can be loaded, and the load output is increased.
When the valve 8 is closed, the unit output load is equal to the compressor output load when the unit output load is at 25%.
Q25％＝cm(tchill_in-tchill_out)
t3‘＝tchill_out
When the part 8 is switched on, when the output load of the unit is at 25%,
t3‘＜tchill_out
i.e. the compressor output load is not at its design operating minimum at this time,
Qcom＝cm(tchill_in-t3')＞Q25％
at the moment, the output load of the unit can be reduced by reducing the running load of the compressor, and the stepless regulation of 0-100 percent of the output load of the unit under the condition of no shutdown is realized.
Based on the same inventive concept, the embodiment of the invention also provides a water cooling system, which comprises a plurality of water cooling units, wherein the plurality of water cooling units comprise at least one screw type water cooling unit.
In a cold water system consisting of a plurality of cold water units, zero-load output under the condition of no stop can be realized by the mode, and stepless regulation of the unit load performance coefficient of 0-100% is realized.
Based on the same inventive concept, an embodiment of the present invention further provides a control method for a screw chiller, fig. 5 is a schematic flow chart of the control method for the screw chiller according to the embodiment of the present invention, and as shown in fig. 5, the control method includes:
s101, detecting the outlet water temperature of cooling water, the inlet water temperature of chilled water and the outlet water temperature of the chilled water of the spiral water chilling unit,
the outlet temperature of the cooling water is the outlet temperature of the cooling water in the cooling water flow path after the cooling water flows 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 the chilled water flows through the evaporator; the chilled water outlet temperature is the outlet water temperature of the chilled water in the chilled water flow path after the chilled water flows through the evaporator;
and S103, controlling a valve and/or a heat exchanger according to the outlet water temperature of the cooling water and the inlet water temperature of the chilled water so as to adjust the chilled outlet water temperature by utilizing the outlet water of the cooling water and adjust the output load of the water chilling unit.
The screw chiller 100 adjusts the temperature of the chilled water by adding the heat exchanger 7 and the valve 8 and cooling the water output by the screw chiller 100, during which the compressor 0 does not need to be stopped. When the temperature of the frozen outlet water reaches a set value, even if the output load of the compression operation reaches the minimum, the unit can reduce the output load range, even realize the zero load output of the unit, ensure that the load output range of the water chilling unit reaches 0-100 percent, and can keep the unit to operate for a long time under the zero load output. The technical problem that the existing screw type water chilling unit cannot realize zero-load output under the condition of no shutdown is solved, on one hand, stepless adjustment of the screw type water chilling unit in a large range of load output can be realized, on the other hand, zero-load output is realized in a non-shutdown mode, and the water chilling unit can be loaded quickly, has high load response speed, and can meet the application requirements of nuclear power and other special occasions on large adjustment range of output load requirements of the water chilling unit and high load change response.
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 zero load output of the screw type water chilling unit, on one hand, stepless adjustment of 0% -100% of load output of the screw type water chilling unit can be achieved, on the other hand, zero load output is achieved through the non-stop mode, rapid loading can be achieved, the load response speed is high, and the application requirements of special occasions such as nuclear power and the like on large adjustment range of output load requirements of the water chilling unit and rapid load change response can be met.
In an alternative embodiment, before controlling the valve and/or the heat exchanger according to the outlet water temperature of the cooling water and the inlet water temperature of the chilled water in step S101, the control method includes:
s101a, acquiring a target output load performance coefficient of the water chilling unit;
s101b, when the target output load performance coefficient of the water chilling unit meets a preset condition, controlling the compressor to operate according to a preset load range, wherein the preset load operation range is larger than or equal to the minimum rated operation load of the compressor.
Preferably, the preset condition is that a target output load performance coefficient of the water chilling unit is not less than 0% and not more than 25%.
In the step S101, the controlling the valve and/or the heat exchanger according to the outlet temperature of the cooling water and the inlet temperature of the chilled water includes:
if the obtained current output load performance coefficient of the water chilling unit is smaller than the target output load performance coefficient, the valve is controlled to be opened or the opening of the valve is increased so as to increase the heat exchange quantity of the cooling water outlet and the chilled water outlet and enable the chilled water outlet temperature to rise;
and if the obtained current output load performance coefficient of the water chilling unit is greater than the target output load performance coefficient, closing the valve or reducing the opening of the valve so as to reduce the heat exchange quantity of the cooling water outlet and the chilled water outlet and reduce the temperature of the chilled water outlet.
Through the above embodiment of the present invention, the following technical effects can be achieved:
1. the load output range of the conventional screw type water chilling unit can be widened by 25-100%, and stepless regulation of 0-100% of the output load of the water chilling unit is realized;
2. the mode that the conventional screw unit needs to be stopped when zero-load output is realized is changed, the water chilling unit can be stopped without stopping in the mode, the zero-load output of the unit is realized, and when the load at the tail end is changed, the output load can be loaded quickly.
In an alternative embodiment, the valve comprises an electrically operated 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 the opening of the valve, so that the load output of the water chilling unit can be accurately controlled; the valve of the electromagnetic valve can be controlled to open and close to adjust the outlet water temperature of the chilled water by utilizing the outlet water of the cooling water, so that the load output of the water chilling unit is adjusted.
In an application scenario, after the valve 8 adopts the electromagnetic valve, the electromagnetic valve can only be controlled to be turned on and off, and the accurate adjustment of the bypass flux of the cooling water cannot be realized, so that the accurate adjustment of the outlet water temperature of the chilled water cannot be realized.
When the output load of the water chilling unit needs to be adjusted to be below 25%, the compressor operates according to the designed minimum load, the valve 8 is electrified, the valve is opened, and the outlet water temperature t of the chilled water ischill_outThe compressor can be loaded to increase the load output when the compressor is lifted to a certain degree.
When the valve 8 is closed, the unit output load is equal to the compressor output load when the unit output load is at 25%.
Q25％＝cm(tchill_in-tchill_out)
t3‘＝tchill_out
When the valve 8 is opened, when the output load of the unit is at 25%,
t3‘＜tchill_out
i.e. the compressor output load is not at its design operating minimum at this time,
Qcom＝cm(tchill_in-t3')＞Q25％
at the moment, the output load of the unit can be reduced by reducing the running load of the compressor, and the stepless regulation of 0-100 percent of the output load of the unit under the condition of no shutdown is realized.
Through the screw type water chilling unit and the control method and system thereof in the embodiment, the following technical effects can be realized:
1. the load output range of the conventional screw type water chilling unit can be widened by 25-100%, and stepless regulation of 0-100% of the output load of the water chilling unit is realized;
2. the mode that the conventional screw unit needs to be stopped when zero-load output is realized is changed, the water chilling unit can be stopped without stopping in the mode, the zero-load output of the unit is realized, and when the load at the tail end is changed, the output load can be loaded quickly.
The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes may be made to the embodiment of the present invention by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (11)
1. A screw chiller, comprising:
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;
a heat exchanger for exchanging heat between the chilled water outlet of the chilled water flow path and the cooling water outlet of the cooling water flow path;
a valve for regulating the flux of the cooling water into the heat exchanger, the valve being disposed at a bypass pipe where the cooling water outlet pipe is connected to the heat exchanger;
a sensor group for detecting the cooling water outlet temperature of the cooling water flowing out of the evaporator in the cooling water flow path, the cooling water inlet temperature and the cooling water outlet temperature of the cooling water flow path;
and the controller is used for controlling the valve and/or the heat exchanger according to the outlet water temperature of the cooling water and the inlet water temperature of the chilled water so as to regulate and control the outlet water temperature of the chilled water and regulate the output load of the water chilling unit.
2. The screw chiller of claim 1, wherein the chiller has an output load performance factor in the range of 0% to 100%.
3. The screw chiller according to claim 1 wherein the heat exchange capacity of the heat exchanger is greater than or equal to a predetermined capacity; wherein the preset quantity is 25% of the output load of the water chilling unit.
4. The screw chiller of claim 1 wherein the heat exchanger is a plate heat exchanger.
5. The screw chiller of claim 4,
the cooling water flow path comprises a cooling water inlet pipe and a cooling water outlet pipe;
the chilled water flow path comprises a chilled water inlet pipe and a chilled water outlet pipe;
the plate heat exchanger is respectively connected with a bypass pipeline of the cooling water outlet pipe and a bypass pipeline of the chilled water outlet pipe,
the valve is arranged at a bypass pipeline where the cooling water outlet pipeline is connected with the plate heat exchanger.
6. The screw chiller of claim 1, wherein the valves comprise electric and/or solenoid valves.
7. A chiller system comprising a plurality of chiller units including at least one screw chiller unit according to any one of claims 1 to 6.
8. A control method for a screw chiller, comprising:
detecting the outlet water temperature of cooling water, the inlet water temperature of chilled water and the outlet water temperature of the chilled water of the spiral water chilling unit,
the outlet water temperature of the cooling water is the outlet water temperature of the cooling water in the cooling water flow path after the cooling water flows through the condenser, and the inlet water temperature of the chilled water is the inlet water temperature of the chilled water in the chilled water flow path before the chilled water flows through the evaporator; the chilled water outlet temperature is the outlet temperature of the chilled water in the chilled water flow path after the chilled water flows through the evaporator;
according to the cooling water outlet temperature, the chilled water inlet temperature control valve and/or the heat exchanger, the chilled water outlet temperature is adjusted by utilizing the cooling water outlet, the output load of the water chilling unit is adjusted, and the valve is arranged at a bypass pipeline connected with the heat exchanger through the cooling water outlet pipeline.
9. The control method of claim 8, before controlling a valve and/or a heat exchanger according to the cooling water outlet temperature, the chilled water inlet temperature, the control method further comprising:
acquiring a target output load performance coefficient of the water chilling unit;
and when the target output load performance coefficient of the water chilling unit meets a preset condition, controlling the compressor to operate according to a preset load range, wherein the preset load operation range is greater than or equal to the minimum rated operation load of the compressor.
10. The control method according to claim 9, wherein the controlling a valve and/or a heat exchanger according to the outlet water temperature of the cooling water, the inlet water temperature of the chilled water comprises:
if the obtained current output load performance coefficient of the water chilling unit is smaller than the target output load performance coefficient, controlling a valve to be opened or increasing the opening of the valve so as to increase the heat exchange quantity between the cooling water outlet and the chilled water outlet and increase the temperature of the chilled water outlet;
and if the obtained current output load performance coefficient of the water chilling unit is greater than the target output load performance coefficient, controlling a valve to be closed or reducing the opening of the valve so as to reduce the heat exchange quantity between the cooling water outlet and the chilled water outlet and reduce the temperature of the chilled water outlet.
11. The control method according to claim 9, wherein the preset condition is that the target output load performance coefficient is 0% or more and 25% or less.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811438929.7A CN109631376B (en) | 2018-11-27 | 2018-11-27 | Screw type water chilling unit and control method and system thereof |
| PCT/CN2019/112397 WO2020108170A1 (en) | 2018-11-27 | 2019-10-22 | Screw-type chiller, control method for same, and system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811438929.7A CN109631376B (en) | 2018-11-27 | 2018-11-27 | Screw type water chilling unit and control method and system thereof |
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| CN109631376A CN109631376A (en) | 2019-04-16 |
| CN109631376B true CN109631376B (en) | 2022-01-28 |
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| CN109631376B (en) * | 2018-11-27 | 2022-01-28 | 珠海格力电器股份有限公司 | Screw type water chilling unit and control method and system thereof |
| CN110530075B (en) * | 2019-09-16 | 2020-11-10 | 珠海格力电器股份有限公司 | Zero-load output non-stop control method, device and unit |
| CN110822752B (en) * | 2019-10-26 | 2020-08-14 | 浙江国祥股份有限公司 | Screw water cooler with capacity adjusting device |
| CN114151986B (en) * | 2020-09-04 | 2023-01-20 | 约克（无锡）空调冷冻设备有限公司 | Water chilling unit |
| CN112856724B (en) * | 2021-01-07 | 2022-07-12 | 丁一 | Control method, device and system of water chilling unit |
| CN112902516B (en) * | 2021-03-08 | 2022-10-21 | 深圳市东洋冷冻设备有限公司 | Control method of water chiller, water chiller and storage medium |
| CN114234401A (en) * | 2021-12-27 | 2022-03-25 | 上海美控智慧建筑有限公司 | Control method and device of ice storage air conditioning system and electronic equipment |
| CN115164452B (en) * | 2022-06-14 | 2024-02-02 | 约克（无锡）空调冷冻设备有限公司 | Condensing equipment reaches heat pump system including it |
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Also Published As
| Publication number | Publication date |
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| CN109631376A (en) | 2019-04-16 |
| WO2020108170A1 (en) | 2020-06-04 |
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