CN107401864B - Anti-freezing cooling system and anti-freezing cooling control method - Google Patents

Anti-freezing cooling system and anti-freezing cooling control method Download PDF

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Publication number
CN107401864B
CN107401864B CN201710804582.2A CN201710804582A CN107401864B CN 107401864 B CN107401864 B CN 107401864B CN 201710804582 A CN201710804582 A CN 201710804582A CN 107401864 B CN107401864 B CN 107401864B
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Prior art keywords
temperature
threshold
refrigerant
current
duration
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CN107401864A (en
Inventor
郭诗迪
胡乾龙
唐育辉
石伟
张丹丹
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Gree Electric Appliances Inc of Zhuhai
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Gree Electric Appliances Inc of Zhuhai
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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
    • F25B41/00—Fluid-circulation arrangements
    • F25B41/30—Expansion means; Dispositions thereof
    • F25B41/31—Expansion valves
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
    • B23Q11/00—Accessories fitted to machine tools for keeping tools or parts of the machine in good working condition or for cooling work; Safety devices specially combined with or arranged in, or specially adapted for use in connection with, machine tools
    • B23Q11/14—Methods or arrangements for maintaining a constant temperature in parts of machine tools
    • B23Q11/141—Methods or arrangements for maintaining a constant temperature in parts of machine tools using a closed fluid circuit for cooling or heating
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B49/00—Arrangement or mounting of control or safety devices
    • F25B49/02—Arrangement or mounting of control or safety devices for compression type machines, plants or systems
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B30/00—Energy efficient heating, ventilation or air conditioning [HVAC]
    • Y02B30/70—Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Devices That Are Associated With Refrigeration Equipment (AREA)

Abstract

The invention discloses an anti-freezing cooling system and an anti-freezing cooling control method, and relates to the field of cooling control. The anti-freezing cooling system comprises a refrigerating circuit and a cooling circuit, a bypass branch is arranged in the refrigerating circuit, two ends of the bypass branch are respectively communicated with an inlet of a condenser and an inlet of an evaporator in the refrigerating circuit, and a refrigerant in the refrigerating circuit exchanges heat with a cooling liquid in the cooling circuit. By adding the bypass branch in the refrigeration branch, part of refrigerant in the refrigeration loop is directly supplied to the evaporator without being refrigerated by the condenser, so that the evaporator is effectively prevented from being frozen due to too low temperature.

Description

Anti-freezing cooling system and anti-freezing cooling control method
Technical Field
The invention relates to the field of cooling control, in particular to an anti-freezing cooling system and an anti-freezing cooling control method.
Background
In modern manufacturing, machine tools are indispensable equipment such as CNC (Computer Numerical Control, numerical control machine), grinding machines, wire cutting machines, and the like. When the machine tool works, the high-speed running of the cutter for cutting the workpiece and the main shaft can generate a large amount of heat, so that the guide rail and the main shaft of the machine tool are thermally deformed, the machining precision of the workpiece is reduced, and the service lives of the cutter and the main shaft are also reduced. There is therefore a need for cooling the machine tool. A machine tool cooler such as an oil cooler (also referred to as an oil cooler) functions to effectively reduce heat generated by cutting of a machine tool and provide machining accuracy of the machine tool.
As shown in fig. 1, a present machine tool cooler system is provided with a refrigeration circuit 1 and a cooling circuit 2, wherein a compressor 11, a condenser 12, an electronic expansion valve 13 and an evaporator 14 are sequentially arranged in the refrigeration circuit 1 according to the flowing direction of a refrigerant, and a fan 15 is further arranged at the condenser 12. The cooling circuit 2 is provided with a pump 21, and the cooling liquid flows through the cooling circuit 2 by the pump 21, so that heat generated by the machine tool is released through the evaporator 14. Arrows in fig. 1 indicate the flow direction of the cooling liquid.
Currently, the evaporator 14 is typically a plate heat exchanger. The plate heat exchanger has the advantages of small size and good heat exchange performance, but the plate heat exchanger also has the defect of easy blockage. In order to avoid clogging of the plate heat exchanger, the cooling liquid is usually filtered by a filter and then supplied to the plate heat exchanger.
However, once the filter fails, the plate heat exchanger becomes clogged, which can lead to freezing out of the evaporator.
Disclosure of Invention
The embodiment of the invention provides an anti-freezing cooling system and an anti-freezing cooling control method, wherein a bypass branch is added in a refrigeration branch, so that part of refrigerant is directly supplied to an evaporator without being refrigerated by a condenser, and the evaporator is effectively prevented from being frozen out due to too low temperature.
According to one aspect of the present invention, there is provided an antifreeze cooling system comprising a refrigeration circuit and a cooling circuit, the refrigeration circuit having a bypass branch, wherein:
the refrigerant in the refrigerating loop exchanges heat with the cooling liquid in the cooling loop;
the two ends of the bypass branch are respectively communicated with the inlet of the condenser and the inlet of the evaporator in the refrigeration loop.
In one embodiment, a bypass valve is provided on the bypass branch.
In one embodiment, the system further comprises a first temperature sensor, wherein:
the first temperature sensor is used for detecting the temperature of the cooling liquid after heat exchange with the refrigerant.
In one embodiment, the system further comprises a second temperature sensor, wherein:
the second temperature sensor is used for detecting the temperature of the refrigerant in the evaporator.
In one embodiment, the above system further comprises a control device, wherein:
the control device adjusts the valve opening of the bypass valve, the working frequency of the compressor in the refrigeration loop and/or the opening of the electronic expansion valve in the refrigeration loop according to the current cooling liquid temperature detected by the first temperature sensor and the current refrigerant temperature detected by the second temperature sensor.
In one embodiment, the control device determines whether the current coolant temperature is greater than a preset temperature value at predetermined time intervals, and turns off the compressor if the current coolant temperature is not greater than the preset temperature value.
In one embodiment, the control device determines whether the current coolant temperature is greater than a first temperature threshold when the current coolant temperature is greater than a preset temperature value, if the coolant temperature is not greater than the first temperature threshold, further determines whether a duration of the current coolant temperature in a range from the second temperature threshold to the first temperature threshold exceeds a temperature duration threshold, and if the duration exceeds the temperature duration threshold, reduces the frequency of the compressor, wherein the first temperature threshold is greater than the second temperature threshold.
In one embodiment, the control device is further configured to further determine whether a temperature drop rate of the refrigerant in the evaporator is greater than a temperature drop rate threshold if the duration does not exceed the temperature duration threshold, and if the temperature drop rate of the refrigerant is greater than the temperature drop rate threshold, increase the opening of the electronic expansion valve.
In one embodiment, the control device is further configured to determine whether the current refrigerant temperature is greater than a second temperature threshold if the temperature drop rate of the refrigerant is not greater than the temperature drop rate threshold, further determine whether the current refrigerant temperature is greater than a third temperature threshold if the current refrigerant temperature is not greater than the second temperature threshold, and open the bypass valve if the current refrigerant temperature is not greater than the third temperature threshold, wherein the third temperature threshold is less than the second temperature threshold.
In one embodiment, the control device is further configured to further determine whether a temperature drop rate of the refrigerant in the evaporator is greater than a temperature drop rate threshold if the temperature drop rate of the refrigerant is greater than the temperature drop rate threshold, open the bypass valve if the temperature drop rate of the refrigerant is not greater than the temperature drop rate threshold, and reduce the frequency of the compressor if the temperature drop rate of the refrigerant is not greater than the temperature drop rate threshold.
In one embodiment, the control device further determines whether the current refrigerant temperature is greater than a fourth temperature threshold after opening the bypass valve, and if the refrigerant temperature is not greater than the fourth temperature threshold, closes the compressor, wherein the fourth temperature threshold is less than the third temperature threshold.
In one embodiment, the control device further determines whether the duration of the current refrigerant temperature from the fourth temperature threshold to the third temperature threshold exceeds the temperature duration threshold if the current refrigerant temperature is greater than the fourth temperature threshold, and if the duration does not exceed the temperature duration threshold, repeatedly performs the step of determining whether the current refrigerant temperature is greater than the first temperature threshold; if the duration exceeds the temperature duration threshold, the compressor is turned off.
In one embodiment, the control device is further configured to further determine whether a duration of the current refrigerant temperature from the second temperature threshold to the first temperature threshold exceeds a temperature duration threshold when the current refrigerant temperature is greater than the second temperature threshold, and close the bypass valve if the duration exceeds the temperature duration threshold.
In one embodiment, the evaporator is a coaxial double pipe heat exchanger.
According to another aspect of the present invention, there is provided an antifreeze cooling control method including:
detecting the temperature of cooling liquid in the cooling loop after heat exchange with the refrigerant in the refrigerating loop and the temperature of the refrigerant in the evaporator in the refrigerating loop;
according to the detected current cooling liquid temperature and the current refrigerant temperature, regulating the valve opening of a bypass valve on a bypass branch, the working frequency of a compressor in a refrigeration loop and/or the opening of an electronic expansion valve in the refrigeration loop;
wherein, the refrigerant in the refrigerating circuit exchanges heat with the cooling liquid in the cooling circuit; a bypass branch is arranged in the refrigeration loop, and two ends of the bypass branch are respectively communicated with an inlet of a condenser and an inlet of an evaporator in the refrigeration loop.
In one embodiment, adjusting the valve opening of the bypass valve on the bypass branch, the operating frequency of the compressor in the refrigeration circuit, and/or the opening of the electronic expansion valve in the refrigeration circuit based on the detected current coolant temperature and current refrigerant temperature includes:
judging whether the current temperature of the cooling liquid is larger than a preset temperature value or not at preset time intervals;
and if the current temperature of the cooling liquid is not greater than the preset temperature value, closing the compressor.
In one embodiment, if the current coolant temperature is greater than a preset temperature value, determining whether the current coolant temperature is greater than a first temperature threshold;
if the temperature of the refrigerant is not greater than the first temperature threshold, further judging whether the duration time of the current temperature of the refrigerant in the interval from the second temperature threshold to the first temperature threshold exceeds a temperature duration threshold, wherein the first temperature threshold is greater than the second temperature threshold;
if the duration exceeds the temperature duration threshold, the frequency of the compressor is reduced.
In one embodiment, if the duration time does not exceed the temperature duration threshold, further determining whether the temperature drop rate of the refrigerant in the evaporator is greater than the temperature drop rate threshold;
if the temperature drop rate of the refrigerant is greater than the temperature drop rate threshold, increasing the opening of the electronic expansion valve.
In one embodiment, if the temperature drop rate of the refrigerant is not greater than the temperature drop rate threshold, determining whether the current temperature of the refrigerant is greater than a second temperature threshold;
if the current refrigerant temperature is not greater than the second temperature threshold, further judging whether the current refrigerant temperature is greater than a third temperature threshold, wherein the third temperature threshold is smaller than the second temperature threshold;
and if the current temperature of the refrigerant is not greater than the third temperature threshold, opening the bypass valve.
In one embodiment, if the current temperature of the refrigerant is greater than the third temperature threshold, further determining whether the temperature drop rate of the refrigerant in the evaporator is greater than the temperature drop rate threshold;
if the temperature drop rate of the refrigerant is greater than the temperature drop rate threshold, opening a bypass valve;
if the temperature drop rate of the refrigerant is not greater than the temperature drop rate threshold, the frequency of the compressor is reduced.
In one embodiment, after the bypass valve is opened, determining whether the current refrigerant temperature is greater than a fourth temperature threshold, wherein the fourth temperature threshold is less than the third temperature threshold;
and if the temperature of the refrigerant is not greater than the fourth temperature threshold, closing the compressor.
In one embodiment, if the current refrigerant temperature is greater than the fourth temperature threshold, further determining whether the duration of the current refrigerant temperature from the fourth temperature threshold to the third temperature threshold exceeds a temperature duration threshold;
if the duration time does not exceed the temperature duration threshold, repeating the step of judging whether the current refrigerant temperature is greater than the first temperature threshold;
if the duration exceeds the temperature duration threshold, the compressor is turned off.
In one embodiment, if the current refrigerant temperature is greater than the second temperature threshold, further determining whether the duration of the current refrigerant temperature from the second temperature threshold to the first temperature threshold exceeds a temperature duration threshold;
if the duration exceeds the temperature duration threshold, the bypass valve is closed.
Other features of the present invention and its advantages will become apparent from the following detailed description of exemplary embodiments of the invention, which proceeds with reference to the accompanying drawings.
Drawings
In order to more clearly illustrate the embodiments of the invention or the technical solutions of the prior art, the drawings which are used in the description of the embodiments or the prior art will be briefly described, it being obvious that the drawings in the description below are only some embodiments of the invention, and that other drawings can be obtained according to these drawings without inventive faculty for a person skilled in the art.
FIG. 1 is a schematic diagram of one embodiment of a prior art machine tool chiller system.
FIG. 2 is a schematic diagram of an embodiment of the antifreeze cooling system of the present invention.
Fig. 3 is a schematic view of another embodiment of the antifreeze cooling system of the present invention.
Fig. 4 is a schematic view of a further embodiment of the antifreeze cooling system of the present invention.
Fig. 5 is a schematic diagram of an embodiment of the antifreeze cooling control method of the present invention.
Fig. 6 is a schematic diagram of another embodiment of the antifreeze cooling control method according to the present invention.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. The following description of at least one exemplary embodiment is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The relative arrangement of the components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless it is specifically stated otherwise.
Meanwhile, it should be understood that the sizes of the respective parts shown in the drawings are not drawn in actual scale for convenience of description.
Techniques, methods, and apparatus known to one of ordinary skill in the relevant art may not be discussed in detail, but should be considered part of the specification where appropriate.
In all examples shown and discussed herein, any specific values should be construed as merely illustrative, and not a limitation. Thus, other examples of the exemplary embodiments may have different values.
It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further discussion thereof is necessary in subsequent figures.
FIG. 2 is a schematic diagram of an embodiment of the antifreeze cooling system of the present invention. As shown in fig. 2, the antifreeze cooling system includes a refrigeration circuit 1 and a cooling circuit 2, and a bypass branch 3 is provided in the refrigeration circuit 1. Wherein:
the refrigerant in the refrigeration circuit 1 exchanges heat with the cooling liquid in the cooling circuit 2, and both ends of the bypass branch 3 are respectively communicated with an inlet of a condenser 12 and an inlet of an evaporator 14 in the refrigeration circuit 1. Therefore, in the circulation process of the refrigerant, part of the refrigerant does not pass through the condenser, but directly passes through the bypass branch to reach the inlet of the evaporator, so that the high-temperature high-pressure refrigerant and the low-temperature low-pressure refrigerant are mixed and then enter the evaporator. Since this part of the refrigerant does not pass through the refrigeration process of the condenser, the evaporator temperature can be ensured not to be too low.
For example, the refrigerant in the refrigeration circuit 1 and the coolant in the cooling circuit 2 may exchange heat in the evaporator 14 of the refrigeration circuit 1.
Alternatively, the evaporator 14 may be a coaxial double pipe heat exchanger or a barrel heat exchanger, etc., so as to effectively overcome the defect that the plate heat exchanger is easy to be blocked and frozen.
According to the anti-freezing cooling system provided by the embodiment of the invention, the bypass branch is added in the refrigeration branch, so that part of refrigerant is directly supplied to the evaporator without being refrigerated by the condenser, and the evaporator is effectively prevented from being frozen due to too low temperature.
Fig. 3 is a schematic view of another embodiment of the antifreeze cooling system of the present invention. As shown in fig. 3, a bypass valve 31 is further provided in the bypass passage 3. By adjusting the opening of the bypass valve 31, the amount of refrigerant passing through the bypass branch can be adjusted so as to adjust the temperature of the evaporator.
Fig. 4 is a schematic view of a further embodiment of the antifreeze cooling system of the present invention. As shown in fig. 4, the antifreeze cooling system further includes a first temperature sensor 4 for detecting the temperature of the coolant after heat exchange with the refrigerant.
In addition, a second temperature sensor 5 for detecting the temperature of the refrigerant in the evaporator 14 may be further included in the antifreeze cooling system.
Optionally, a control device (not shown in the figures) is also included in the antifreeze cooling system. The control device adjusts the valve opening of the bypass valve 31, the operating frequency of the compressor 11 in the refrigeration circuit 1, and/or the opening of the electronic expansion valve 13 in the refrigeration circuit 1 according to the current coolant temperature detected by the first temperature sensor 4 and the current coolant temperature detected by the second temperature sensor 5. Thereby avoiding the evaporator from being frozen out due to the too low temperature.
The control scheme of the control device will be described below by way of a specific example.
1) The control device judges whether the current coolant temperature of the evaporator is greater than a preset temperature value at predetermined time intervals, and if the current coolant temperature is not greater than the preset temperature value, the compressor 11 is turned off.
That is, if the current coolant temperature is less than or equal to the preset temperature value X, it indicates that the current evaporator refrigerant temperature is too low, and the compressor may be turned off.
2) The control device judges whether the current refrigerant temperature (hereinafter referred to as evaporating temperature) of the evaporator is greater than a first temperature threshold T1 under the condition that the current coolant temperature is greater than a preset temperature value, and can maintain the current compressor operating frequency unchanged if the evaporating temperature is greater than the first temperature threshold T1.
3) If the evaporating temperature is not greater than the first temperature threshold T1, the control device further determines whether the duration of the current evaporating temperature in the interval from the second temperature threshold T2 to the first temperature threshold T1 exceeds the temperature duration threshold, and if the duration exceeds the temperature duration threshold B, the frequency of the compressor 11 is reduced, wherein the first temperature threshold T1 is greater than the second temperature threshold T2.
That is, if the temperature of the refrigerant in the evaporator is within the [ T2, T1] interval and the duration exceeds the threshold B, the compressor can be subjected to the frequency-reducing process at this time, so that an excessive change in the temperature of the refrigerant can be avoided.
4) The control device is further configured to further determine whether the temperature drop rate of the refrigerant in the evaporator 14 is greater than a temperature drop rate threshold E if the duration does not exceed the temperature duration threshold B, and if the temperature drop rate of the refrigerant is greater than the temperature drop rate threshold E, increase the opening of the electronic expansion valve 13.
That is, if the temperature drop speed of the refrigerant exceeds the threshold E, the opening of the electronic expansion valve can be adjusted to slow down the temperature drop speed of the refrigerant.
5) The control device is further configured to determine whether the current evaporating temperature is greater than a second temperature threshold T2 if the temperature drop rate of the refrigerant is not greater than the temperature drop rate threshold E, further determine whether a duration of the current evaporating temperature between the second temperature threshold T2 and the first temperature threshold T1 exceeds a temperature duration threshold B if the current evaporating temperature is greater than the second temperature threshold, and close the bypass valve 31 if the duration exceeds the temperature duration threshold; if the duration does not exceed the temperature duration threshold, the current operating frequency of the compressor may be maintained unchanged.
That is, when the current refrigerant temperature of the evaporator is greater than T2 and the duration exceeds B, the bypass valve may be closed, i.e., the previous refrigerant temperature is appropriate, and bypass processing of the refrigerant in the refrigeration circuit is not required.
6) If the current evaporating temperature is not greater than the second temperature threshold T2, further judging whether the current evaporating temperature is greater than a third temperature threshold T3, and if the current evaporating temperature is not greater than the third temperature threshold T3, opening the bypass valve 31, wherein the third temperature threshold T3 is smaller than the second temperature threshold T2.
That is, when the current refrigerant temperature of the evaporator is too low, the bypass valve is opened so as to realize the mixing of the refrigerants with different temperatures in the refrigeration loop.
7) The control device is further configured to further determine whether the temperature drop rate of the refrigerant in the evaporator 14 is greater than a temperature drop rate threshold E when the current evaporation temperature is greater than a third temperature threshold T3, open the bypass valve 31 if the temperature drop rate of the refrigerant is greater than the temperature drop rate threshold E, and reduce the frequency of the compressor 11 if the temperature drop rate of the refrigerant is not greater than the temperature drop rate threshold E.
That is, if the evaporation temperature is not too low, but the temperature drop rate exceeds the threshold E, the bypass valve may be opened at this time as a protection system.
8) The control device further judges whether the current evaporating temperature is greater than a fourth temperature threshold T4 after opening the bypass valve 31, and if the evaporating temperature is not greater than the fourth temperature threshold T4, the control device turns off the compressor, wherein the fourth temperature threshold T4 is smaller than the third temperature threshold T3.
For example, T4 may be less than zero degrees and T3 may be slightly above zero degrees.
That is, after the bypass valve is opened, the evaporating temperature is still too low, and the compressor may be turned off for protecting the system.
9) The control device further judges whether the duration of the current evaporating temperature from the fourth temperature threshold T4 to the third temperature threshold T3 exceeds a temperature duration threshold under the condition that the current evaporating temperature is larger than the fourth temperature threshold T4, and if the duration does not exceed the temperature duration threshold B, the step of judging whether the current evaporating temperature is larger than the first temperature threshold is repeatedly executed so as to carry out cyclic processing; if the duration exceeds the temperature duration threshold B, the compressor is turned off.
That is, if the evaporating temperature is not too low, but the duration in the interval [ T4, T3] exceeds the threshold B, which indicates that opening the bypass branch does not raise the evaporating temperature, the compressor may be turned off for system safety.
In addition, the pump 21 in the cooling circuit 2 may be a variable frequency pump, so that when the coolant temperature is low, the frequency of the pump 21 may be increased to increase the flow rate of the coolant so as to increase the temperature of the coolant in the evaporator.
Fig. 5 is a schematic diagram of an embodiment of the antifreeze cooling control method of the present invention. Wherein:
step 501, detecting the temperature of the cooling liquid in the cooling circuit after heat exchange with the refrigerant in the refrigeration circuit and the temperature of the refrigerant in the evaporator in the refrigeration circuit.
Step 502, according to the detected current cooling liquid temperature and the detected temperature of the refrigerant in the evaporator, adjusting the valve opening of the bypass valve on the bypass branch, the working frequency of the compressor in the refrigeration loop and/or the opening of the electronic expansion valve in the refrigeration loop.
Wherein, the refrigerant in the refrigerating circuit and the cooling liquid in the cooling circuit exchange heat in the evaporator of the refrigerating circuit; a bypass branch is arranged in the refrigeration loop, and two ends of the bypass branch are respectively communicated with an inlet of a condenser and an inlet of an evaporator in the refrigeration loop.
According to the antifreezing cooling control method provided by the embodiment of the invention, the bypass branch is added in the refrigeration branch, so that part of refrigerant is directly supplied to the evaporator without being refrigerated by the condenser, and according to the detected current temperature of the cooling liquid and the temperature of the refrigerant in the evaporator, the valve opening of the bypass valve on the bypass branch, the working frequency of the compressor in the refrigeration loop and/or the opening of the electronic expansion valve in the refrigeration loop are adjusted, so that the evaporator is effectively prevented from being frozen out due to the fact that the temperature is too low.
The present invention will be described below by way of specific examples, as shown in fig. 6.
In step 601, it is determined whether the current coolant temperature is greater than a preset temperature value X at predetermined time intervals.
If the current coolant temperature is greater than the preset temperature value X, step 602 is performed; if the current coolant temperature is not greater than the preset temperature value X, step 614 is performed.
In step 602, it is determined whether the current evaporating temperature (i.e. the temperature of the refrigerant in the evaporator) is greater than a first temperature threshold T1.
If the evaporation temperature is greater than the first temperature threshold T1, step 603 is performed; if the evaporation temperature is not greater than the first temperature threshold T1, step 604 is performed.
Step 603, maintaining the existing operating frequency of the compressor.
Step 604, determining whether the duration of the current evaporating temperature in the interval from the second temperature threshold to the first temperature threshold exceeds the temperature duration threshold B, wherein the first temperature threshold is greater than the second temperature threshold.
If the duration exceeds the temperature duration threshold, then step 605 is performed; if the duration does not exceed the temperature duration threshold B, step 606 is performed.
Step 605, decreasing the operating frequency of the compressor.
Step 606, it is determined whether the temperature drop rate of the refrigerant in the evaporator is greater than a temperature drop rate threshold E.
If the temperature drop rate of the refrigerant is greater than the temperature drop rate threshold E, step 607 is performed; if the temperature drop rate of the refrigerant is not greater than the temperature drop rate threshold E, step 608 is performed.
Step 607 increases the opening of the electronic expansion valve.
In step 608, it is determined whether the current evaporating temperature is greater than the second temperature threshold T2.
If the current evaporating temperature is not greater than the second temperature threshold T2, step 609 is executed; if the current evaporating temperature is greater than the second temperature threshold T2, step 615 is executed.
Step 609, it is determined whether the current evaporating temperature is greater than a third temperature threshold T3, wherein the third temperature threshold is less than the second temperature threshold.
If the current evaporating temperature is not greater than the third temperature threshold T3, step 610 is performed. If the current evaporating temperature is greater than the third temperature threshold T3, step 611 is performed.
Step 610, open a bypass valve.
In step 611, it is determined whether the temperature drop rate of the refrigerant in the evaporator is greater than a temperature drop rate threshold E.
If the temperature drop rate of the refrigerant is greater than the temperature drop rate threshold, then step 610 is performed; if the temperature drop rate of the refrigerant is not greater than the temperature drop rate threshold, step 605 is performed.
Step 612, after the bypass valve is opened, it is determined whether the current evaporating temperature is greater than a fourth temperature threshold T4, wherein the fourth temperature threshold T4 is less than the third temperature threshold T3.
If the evaporation temperature is not greater than the fourth temperature threshold T4, then step 614 is performed; if the current evaporating temperature is greater than the fourth temperature threshold T4, step 613 is performed.
In step 613, it is determined whether the duration of the current evaporating temperature in the interval from the fourth temperature threshold T4 to the third temperature threshold T3 exceeds the temperature duration threshold B.
If the duration does not exceed the temperature duration threshold, then step 602 is performed; if the duration exceeds the temperature duration threshold, step 614 is performed.
At step 614, the compressor is turned off.
In step 615, it is determined whether the duration of the current evaporating temperature in the interval from the second temperature threshold T2 to the first temperature threshold T1 exceeds the temperature duration threshold B.
If the duration does not exceed the temperature duration threshold B, then step 603 is performed; if the duration exceeds the temperature duration threshold B, step 616 is performed.
Step 616, the bypass valve is closed.
In addition, the pump 21 in the cooling circuit 2 may be a variable frequency pump, so that when the coolant temperature is low, the frequency of the pump 21 may be increased to increase the flow rate of the coolant so as to increase the temperature of the coolant in the evaporator.
By implementing the invention, the following beneficial effects can be obtained:
1) And a bypass branch is added in the refrigeration loop, and the frequency of the compressor, the opening of a bypass valve and the opening of an electronic expansion valve are cooperatively controlled according to the evaporating temperature, the temperature of the cooling liquid after heat exchange with the refrigerant and other parameters so as to reduce the freezing probability of the evaporator.
2) The evaporator uses a coaxial double-pipe heat exchanger to further reduce the possibility of freezing damage.
It will be understood by those skilled in the art that all or part of the steps for implementing the above embodiments may be implemented by hardware, or may be implemented by a program for instructing relevant hardware, where the program may be stored in a computer readable storage medium, and the storage medium may be a read-only memory, a magnetic disk or an optical disk, etc.
The description of the present invention has been presented for purposes of illustration and description, and is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated.

Claims (20)

1. The utility model provides a cooling system prevents frostbite, its characterized in that includes refrigeration circuit (1), cooling circuit (2), first temperature sensor (4), second temperature sensor (5) and controlling means, be equipped with bypass branch road (3) in refrigeration circuit (1), wherein:
two ends of the bypass branch (3) are respectively communicated with an inlet of a condenser (12) and an inlet of an evaporator (14) in the refrigeration loop (1);
the refrigerant in the refrigerating circuit (1) exchanges heat with the cooling liquid in the cooling circuit (2);
the first temperature sensor (4) is used for detecting the temperature of the cooling liquid after heat exchange with the refrigerant;
the second temperature sensor (5) is used for detecting the temperature of the refrigerant in the evaporator (14);
the control device is used for judging whether the current cooling liquid temperature detected by the first temperature sensor (4) is larger than a preset temperature value or not at preset time intervals, judging whether the current cooling liquid temperature detected by the second temperature sensor (5) is larger than a first temperature threshold or not under the condition that the current cooling liquid temperature is larger than the preset temperature value, further judging whether the duration time of the current cooling liquid temperature in a range from the second temperature threshold to the first temperature threshold exceeds a temperature duration threshold or not if the current cooling liquid temperature is not larger than the first temperature threshold, and reducing the frequency of a compressor (11) in the refrigerating circuit (1) if the duration time exceeds the temperature duration threshold, wherein the first temperature threshold is larger than the second temperature threshold.
2. The system of claim 1, wherein the system further comprises a controller configured to control the controller,
and a bypass valve (31) is arranged on the bypass branch (3).
3. The system of claim 2, wherein the system further comprises a controller configured to control the controller,
the control device is used for switching off the compressor (11) when the current cooling liquid temperature is not greater than a preset temperature value.
4. The system of claim 3, wherein the system further comprises a controller configured to control the controller,
the control device is further used for further judging whether the temperature drop rate of the refrigerant in the evaporator (14) is greater than a temperature drop rate threshold under the condition that the duration time does not exceed the temperature duration threshold, and increasing the opening of the electronic expansion valve (13) in the refrigeration loop (1) if the temperature drop rate of the refrigerant is greater than the temperature drop rate threshold.
5. The system of claim 4, wherein the system further comprises a controller configured to control the controller,
the control device is further configured to determine, when the temperature drop rate of the refrigerant is not greater than a temperature drop rate threshold, whether the current refrigerant temperature is greater than a second temperature threshold, if the current refrigerant temperature is not greater than the second temperature threshold, further determine whether the current refrigerant temperature is greater than a third temperature threshold, and if the current refrigerant temperature is not greater than the third temperature threshold, open the bypass valve (31), where the third temperature threshold is less than the second temperature threshold.
6. The system of claim 5, wherein the system further comprises a controller configured to control the controller,
the control device is further configured to further determine, when the temperature of the current refrigerant is greater than a third temperature threshold, whether a temperature drop rate of the refrigerant in the evaporator (14) is greater than the temperature drop rate threshold, open the bypass valve (31) if the temperature drop rate of the refrigerant is greater than the temperature drop rate threshold, and reduce the frequency of the compressor (11) if the temperature drop rate of the refrigerant is not greater than the temperature drop rate threshold.
7. The system of claim 5, wherein the system further comprises a controller configured to control the controller,
the control device further judges whether the current refrigerant temperature is greater than a fourth temperature threshold after opening the bypass valve (31), and if the current refrigerant temperature is not greater than the fourth temperature threshold, the control device closes the compressor, wherein the fourth temperature threshold is smaller than the third temperature threshold.
8. The system of claim 7, wherein the system further comprises a controller configured to control the controller,
the control device further judges whether the duration time from the fourth temperature threshold to the third temperature threshold exceeds a temperature duration threshold or not under the condition that the current refrigerant temperature is larger than the fourth temperature threshold, and if the duration time does not exceed the temperature duration threshold, the step of judging whether the current refrigerant temperature is larger than the first temperature threshold is repeatedly executed; if the duration exceeds the temperature duration threshold, the compressor is turned off.
9. The system of claim 5, wherein the system further comprises a controller configured to control the controller,
the control device is further configured to further determine, if the duration of the current refrigerant temperature from the second temperature threshold to the first temperature threshold exceeds a temperature duration threshold, if the duration exceeds the temperature duration threshold, close the bypass valve (31).
10. The system of any one of claims 1-9, wherein,
the evaporator (14) is a coaxial double-pipe heat exchanger.
11. An antifreeze cooling control method, characterized by comprising:
detecting the temperature of cooling liquid in the cooling loop after heat exchange with the refrigerant in the refrigerating loop and the temperature of the refrigerant in the evaporator in the refrigerating loop;
judging whether the current temperature of the cooling liquid is larger than a preset temperature value or not at preset time intervals;
judging whether the current coolant temperature is greater than a first temperature threshold or not under the condition that the current coolant temperature is greater than a preset temperature value;
if the current refrigerant temperature is not greater than the first temperature threshold, further judging whether the duration time of the current refrigerant temperature in a range from the second temperature threshold to the first temperature threshold exceeds a temperature duration threshold, wherein the first temperature threshold is greater than the second temperature threshold;
if the duration exceeds a temperature duration threshold, reducing the frequency of a compressor in the refrigeration loop;
wherein, the refrigerant in the refrigerating loop exchanges heat with the cooling liquid in the cooling loop; and a bypass branch is arranged in the refrigeration loop, and two ends of the bypass branch are respectively communicated with an inlet of a condenser and an inlet of the evaporator in the refrigeration loop.
12. The method as recited in claim 11, further comprising:
and if the current temperature of the cooling liquid is not greater than a preset temperature value, closing the compressor.
13. The method of claim 12, wherein the step of determining the position of the probe is performed,
further judging whether the temperature drop rate of the refrigerant in the evaporator is greater than a temperature drop rate threshold under the condition that the duration time does not exceed the temperature duration threshold;
and if the temperature drop rate of the refrigerant is greater than a temperature drop rate threshold, increasing the opening of an electronic expansion valve in the refrigeration loop.
14. The method of claim 13, wherein the step of determining the position of the probe is performed,
judging whether the temperature of the current refrigerant is greater than a second temperature threshold or not under the condition that the temperature drop rate of the refrigerant is not greater than a temperature drop rate threshold;
if the current refrigerant temperature is not greater than the second temperature threshold, further judging whether the current refrigerant temperature is greater than a third temperature threshold, wherein the third temperature threshold is smaller than the second temperature threshold;
and if the current refrigerant temperature is not greater than a third temperature threshold, opening a bypass valve on the bypass branch.
15. The method of claim 14, wherein the step of providing the first information comprises,
further judging whether the temperature drop rate of the refrigerant in the evaporator is greater than a temperature drop rate threshold or not under the condition that the temperature of the current refrigerant is greater than a third temperature threshold;
if the temperature drop rate of the refrigerant is greater than a temperature drop rate threshold, opening the bypass valve;
and if the temperature drop rate of the refrigerant is not greater than the temperature drop rate threshold, reducing the frequency of the compressor.
16. The method of claim 15, wherein the step of determining the position of the probe is performed,
after the bypass valve is opened, judging whether the current refrigerant temperature is greater than a fourth temperature threshold, wherein the fourth temperature threshold is smaller than a third temperature threshold;
and if the current refrigerant temperature is not greater than the fourth temperature threshold, closing the compressor.
17. The method of claim 16, wherein the step of determining the position of the probe comprises,
further judging whether the duration time from the current refrigerant temperature to the third temperature threshold exceeds a temperature duration threshold or not under the condition that the current refrigerant temperature is larger than the fourth temperature threshold;
if the duration time does not exceed the temperature duration threshold, repeating the step of judging whether the current refrigerant temperature is greater than a first temperature threshold;
if the duration exceeds the temperature duration threshold, the compressor is turned off.
18. The method of claim 15, wherein the step of determining the position of the probe is performed,
further judging whether the duration time of the current refrigerant temperature in the interval from the second temperature threshold to the first temperature threshold exceeds a temperature duration threshold or not under the condition that the current refrigerant temperature is larger than the second temperature threshold;
and closing the bypass valve if the duration exceeds the temperature duration threshold.
19. An antifreeze cooling control device comprising:
a memory configured to store instructions;
a processor coupled to the memory, the processor configured to perform the method of any of claims 11-18 based on instructions stored by the memory.
20. A computer readable storage medium storing computer instructions which, when executed by a processor, implement the method of any one of claims 11-18.
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CN110793159B (en) * 2019-11-19 2021-10-26 宁波奥克斯电气股份有限公司 Air conditioner refrigeration anti-freezing protection control method and device and air conditioner
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