CN110762915B - Intelligent defrosting method of refrigeration system based on opening degree of electronic expansion valve - Google Patents
Intelligent defrosting method of refrigeration system based on opening degree of electronic expansion valve Download PDFInfo
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- CN110762915B CN110762915B CN201911049427.XA CN201911049427A CN110762915B CN 110762915 B CN110762915 B CN 110762915B CN 201911049427 A CN201911049427 A CN 201911049427A CN 110762915 B CN110762915 B CN 110762915B
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- expansion valve
- temperature
- electronic expansion
- refrigeration
- opening
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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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- 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
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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
- F25B47/00—Arrangements for preventing or removing deposits or corrosion, not provided for in another subclass
- F25B47/02—Defrosting cycles
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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
- F25D—REFRIGERATORS; COLD ROOMS; ICE-BOXES; COOLING OR FREEZING APPARATUS NOT OTHERWISE PROVIDED FOR
- F25D17/00—Arrangements for circulating cooling fluids; Arrangements for circulating gas, e.g. air, within refrigerated spaces
- F25D17/04—Arrangements for circulating cooling fluids; Arrangements for circulating gas, e.g. air, within refrigerated spaces for circulating air, e.g. by convection
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- 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
Abstract
The invention relates to a method for intelligently defrosting a refrigeration system based on the opening degree of an electronic expansion valve, which controls the superheat parameter of the refrigeration system by combining a fuzzy PID algorithm with the electronic expansion valve, utilizes the characteristics of strong repeatability and time lag of the whole refrigeration system on the basis, comprehensively utilizes the modern intelligent technologies such as the Internet of things technology, fuzzy control and the like, takes the final opening degree of the last refrigeration cycle of the electronic expansion valve and the reference opening degree of the electronic expansion valve as parameters, combines the intelligent algorithm, judges the frosting condition of an evaporator of the refrigeration system, and enters the defrosting process of the refrigeration system as required to finish the defrosting of the refrigeration system as required. The application of the technology realizes the intelligent prediction and judgment of the frost amount of the evaporator, provides a reliable basis for realizing defrosting of the refrigerating system according to needs, improves the overall operating efficiency of the refrigerating system, and achieves the aims of effectively saving energy and reducing consumption.
Description
Technical Field
The invention relates to a refrigeration technology and an intelligent control technology, in particular to an intelligent defrosting method of a refrigeration system based on the opening degree of an electronic expansion valve.
Background
The defrosting control is always a technical difficulty of a refrigeration system, particularly a commercial refrigeration and cold storage refrigeration system, and the operation stability and the operation efficiency of the whole refrigeration system are directly influenced by the quality of the defrosting effect. And how to judge the frost amount of the evaporator so as to realize intelligent defrosting according to needs, which becomes the core problem of defrosting control. The defrosting of the existing refrigerating system mostly adopts a timing defrosting mode, and defrosting control is carried out according to a fixed time interval, so that the refrigerating system is difficult to adapt to the complex working condition that the articles in a refrigeration house change continuously, excessive defrosting is easily caused to influence the refrigerating effect, or the defrosting is not timely to cause the excessive frost amount of an evaporator, and the refrigerating efficiency of the system is reduced.
Disclosure of Invention
The invention aims to provide an intelligent defrosting method of a refrigeration system based on the opening of an electronic expansion valve, aiming at the defects of the existing timing defrosting control, the method uses a fuzzy PID algorithm to combine with the electronic expansion valve to control the superheat parameter of the refrigeration system, and utilizes the characteristics of strong repeatability and time lag of the whole refrigeration system on the basis, and comprehensively uses the modern intelligent technologies such as the internet of things technology, fuzzy control and the like, uses the ending opening of the last refrigeration cycle of the electronic expansion valve and the reference opening of the electronic expansion valve as parameters, combines with the intelligent algorithm to judge the frosting condition of an evaporator of the refrigeration system, and enters the defrosting process of the refrigeration system as required to finish the defrosting of the refrigeration system as required.
The technical scheme of the invention is as follows:
an intelligent defrosting method of a refrigeration system based on the opening of an electronic expansion valve judges the frosting amount of an evaporator through the opening of the electronic expansion valve when a refrigeration cycle is finished, and intelligent on-demand defrosting control is achieved. The intelligent method comprises the following control steps:
1) after the system is started and cooled, the system enters a standby mode and waits for the temperature of the storage to reach the preset high-temperature starting temperature; when the temperature of the storage reaches the high-temperature starting temperature, the system enters a refrigeration state, firstly enters a refrigeration preparation state, judges the shortest stopping time of a compressor, judges the pressure difference between high pressure and low pressure, and adjusts the electronic expansion valve to a preset opening degree;
2) when the refrigeration condition is met, firstly, opening an evaporation fan and a condensation fan, then, opening a compressor, and entering a normal refrigeration state; in the refrigeration process, closed-loop real-time control is carried out on the superheat degree parameter of the refrigeration system according to a preset superheat degree target value by adjusting the opening degree of the electronic expansion valve in real time according to a fuzzy PID algorithm; in the control process, along with the reduction of the warehouse temperature and the evaporation temperature, the opening degree of the electronic expansion valve is gradually reduced, but the superheat degree parameter is relatively stable;
3) in the refrigeration process, the opening of the electronic expansion valve is controlled by an algorithm to change the liquid supply amount of the evaporator of the system, and on the basis of fixing the algorithm, the opening of the expansion valve is related to the reservoir temperature, the target superheat degree and the frost formation amount of the evaporator, so that the frost formation amount of the evaporator is intelligently judged by the opening of the electronic expansion valve under the condition of stable superheat degree;
4) judging whether the temperature of the storage reaches the low-temperature shutdown temperature in the refrigeration process, closing the compressor and the two fans when the temperature reaches the low-temperature shutdown temperature, judging whether the temperature is in the first refrigeration cycle after starting or after defrosting, and if so, recording the final opening value k of the electronic expansion valve at the moment and updating the opening value k into a register;
5) if the temperature is not the first refrigeration cycle, the final electronic expansion valve opening value k1 at this time and the reference electronic expansion valve opening k stored in the register are calculated to obtain the value of & k-k 1.
6) And when the & k value is larger than the set threshold value, entering a defrosting mode, and entering a step 1 standby mode after defrosting is finished. And when the & k value is smaller than the set threshold value, entering a standby mode in the step 1 and waiting for the next refrigeration cycle.
Preferably, the throttling device of the refrigeration system adopts a fuzzy PID method to carry out closed-loop control on the system superheat degree parameter by controlling the opening degree of the electronic expansion valve.
Preferably, the refrigeration system is connected with a temperature sensor and a low-pressure sensor at an evaporator outlet, obtains a real-time evaporation temperature T1 through low-pressure, and obtains an accurate system superheat degree T-T2-T1 through calculation of an evaporator outlet temperature T2 measured by the evaporator outlet temperature sensor, so as to provide a basis for control of the electronic expansion valve.
Preferably, the intelligent defrosting method is provided with high-pressure and low-pressure alarm control, and when the high pressure or the low pressure exceeds the limit, the system outputs an alarm signal.
The invention has the advantages and beneficial effects that:
the invention utilizes the combination of the electronic expansion valve and the superheat degree control of the fuzzy PID, fully utilizes the characteristics of quick response and stable control of the electronic expansion valve, can ensure that the whole refrigeration system can run efficiently, can also utilize the high repeatability of the system under the condition of unchanged set parameters, takes the final refrigerating opening degree of the electronic expansion valve as a judgment basis, and enters the defrosting process as required, thereby improving the running stability and defrosting efficiency of the refrigeration system, really realizing the intelligent judgment of the frost amount of the evaporator and defrosting as required. The method realizes the intelligent prediction and judgment of the frost amount of the evaporator, provides a reliable basis for realizing the defrosting of the refrigeration system according to the requirement, improves the overall operation efficiency of the refrigeration system, and achieves the aims of effectively saving energy and reducing consumption. Therefore, the invention has important practical guiding significance and wide market prospect and social and economic values.
Drawings
FIG. 1 is a schematic diagram of a control method of the present invention;
fig. 2 is a schematic diagram of a refrigeration system and sensor distribution of the present invention.
Detailed Description
The following description of the embodiments of the present invention refers to the accompanying drawings:
referring to fig. 1, a method for intelligently defrosting a refrigeration system based on the opening of an electronic expansion valve judges the frosting amount of an evaporator according to the opening of the electronic expansion valve when a refrigeration cycle is finished, so as to realize intelligent on-demand defrosting control. The intelligent method comprises the following control steps:
1) after the system is started and cooled, the system enters a standby mode and waits for the temperature of the storage to reach the preset high-temperature starting temperature; when the temperature of the storage reaches the high-temperature starting temperature, the system enters a refrigeration state, firstly enters a refrigeration preparation state, judges the shortest stopping time of a compressor, judges the pressure difference between high pressure and low pressure, and adjusts the electronic expansion valve to a preset opening degree;
2) when the refrigeration condition is met, firstly, opening an evaporation fan and a condensation fan, then, opening a compressor, and entering a normal refrigeration state; in the refrigeration process, closed-loop real-time control is carried out on the superheat degree parameter of the refrigeration system according to a preset superheat degree target value by adjusting the opening degree of the electronic expansion valve in real time according to a fuzzy PID algorithm; in the control process, along with the reduction of the warehouse temperature and the evaporation temperature, the opening degree of the electronic expansion valve is gradually reduced, but the superheat degree parameter is relatively stable;
3) in the refrigeration process, the opening of the electronic expansion valve is controlled by an algorithm to change the liquid supply amount of the evaporator of the system, and on the basis of fixing the algorithm, the opening of the expansion valve is related to the reservoir temperature, the target superheat degree and the frost formation amount of the evaporator, so that the frost formation amount of the evaporator is intelligently judged by the opening of the electronic expansion valve under the condition of stable superheat degree;
4) judging whether the temperature of the storage reaches the low-temperature shutdown temperature in the refrigeration process, closing the compressor and the two fans when the temperature reaches the low-temperature shutdown temperature, judging whether the temperature is in the first refrigeration cycle after starting or after defrosting, and if so, recording the final opening value k of the electronic expansion valve at the moment and updating the opening value k into a register;
5) if the current refrigeration cycle is not the first refrigeration cycle, the final electronic expansion valve opening value k1 and the reference electronic expansion valve opening k stored in the register are calculated to obtain & k.
6) And when the & k value is larger than the set threshold value, entering a defrosting mode, and entering a step 1 standby mode after defrosting is finished. And when the & k value is smaller than the set threshold value, entering a standby mode in the step 1 and waiting for the next refrigeration cycle.
7) In the defrosting mode, a bypass solenoid valve M1 shown in FIG. 2 is firstly opened, after the high-pressure and low-pressure pressures are balanced, the compressor is opened to start timing, and hot fluorine is introduced into the evaporator to realize bypass hot fluorine defrosting.
8) And when the set defrosting time or the evaporating temperature is greater than 5 ℃, closing the bypass electromagnetic valve and closing the compressor. The drip time is entered and the timer is started.
9) And after the timing reaches the set dripping time, the whole defrosting process is completed, and the standby mode is entered.
Fig. 2 is a schematic diagram of a refrigeration system and sensor distribution of the present invention. The compressor sucks in the low-pressure steam from the evaporator in a refrigeration state, raises the pressure and sends the steam to the condenser, the steam is condensed into high-pressure liquid in the condenser, the liquid is throttled by the electronic expansion valve and becomes low-pressure liquid, the low-pressure liquid is sent to the evaporator, the liquid absorbs heat in the evaporator and is vaporized, the low-pressure liquid is changed into a steam form, and the circulating refrigeration is completed. In the defrosting state, the main electronic expansion valve is closed, the bypass electromagnetic valve is opened, and the high-pressure high-heat refrigerant compressed by the compressor directly enters the evaporator through the bypass electromagnetic valve to heat and defrost the evaporator, so that the hot gas bypass defrosting process is completed.
In fig. 2, a temperature sensor is arranged at the outlet of the evaporator to measure the outlet temperature of the evaporator, a low-pressure sensor is arranged at the inlet of the low-pressure loop compressor, and the corresponding evaporation temperature is calculated by looking up a table according to the characteristics of the refrigerant according to the low-pressure value, so that an accurate superheat value is obtained and is used as the basis for controlling the opening degree of the electronic expansion valve by using the fuzzy PID. And a high-pressure sensor is arranged at the outlet of the compressor, and high-pressure and low-pressure monitoring and early warning are realized according to real-time high-pressure and low-pressure.
Claims (3)
1. The utility model provides a method of refrigerating system intelligence defrosting based on electronic expansion valve opening, judges evaporimeter frosting amount through electronic expansion valve opening when refrigeration cycle finishes, realizes intelligent defrosting control as required, its characterized in that: the intelligent method comprises the following control steps:
1) after the system is started and cooled, the system enters a standby mode and waits for the temperature of the storage to reach the preset high-temperature starting temperature; when the temperature of the storage reaches the high-temperature starting temperature, the system enters a refrigeration state, firstly enters a refrigeration preparation state, judges the shortest stopping time of a compressor, judges the pressure difference between high pressure and low pressure, and adjusts the electronic expansion valve to a preset opening degree;
2) when the refrigeration condition is met, firstly, opening an evaporation fan and a condensation fan, then, opening a compressor, and entering a normal refrigeration state; in the refrigeration process, closed-loop real-time control is carried out on the superheat degree parameter of the refrigeration system according to a preset superheat degree target value by adjusting the opening degree of the electronic expansion valve in real time according to a fuzzy PID algorithm; in the control process, along with the reduction of the warehouse temperature and the evaporation temperature, the opening degree of the electronic expansion valve is gradually reduced, but the superheat degree parameter is relatively stable;
3) in the refrigeration process, the opening of the electronic expansion valve is controlled by an algorithm to change the liquid supply amount of the evaporator of the system, and on the basis of fixing the algorithm, the opening of the expansion valve is related to the reservoir temperature, the target superheat degree and the frost formation amount of the evaporator, so that the frost formation amount of the evaporator is intelligently judged by the opening of the electronic expansion valve under the condition of stable superheat degree;
4) judging whether the temperature of the storage reaches the low-temperature shutdown temperature in the refrigeration process, closing the compressor and the two fans when the temperature reaches the low-temperature shutdown temperature, judging whether the temperature is in the first refrigeration cycle after starting or after defrosting, and if so, recording the final opening value k of the electronic expansion valve at the moment and updating the opening value k into a register;
5) if the current refrigeration cycle is not the first refrigeration cycle, calculating the final opening value k1 of the electronic expansion valve and the opening k of the reference electronic expansion valve stored in the register to obtain k-k 1;
6) when the & k value is larger than a set threshold value, entering a defrosting mode, and entering a standby mode in the step 1 after defrosting is finished; and when the & k value is smaller than the set threshold value, entering a standby mode in the step 1 and waiting for the next refrigeration cycle.
2. The intelligent defrosting method for a refrigeration system according to claim 1, characterized in that: the refrigerating system is connected with a temperature sensor and a low-pressure sensor at an evaporator outlet, real-time evaporation temperature T1 is obtained through low-pressure table look-up, and accurate system superheat degree T-T2-T1 is obtained through calculation of evaporator outlet temperature T2 measured by the evaporator outlet temperature sensor, so that a basis is provided for control of the electronic expansion valve.
3. The intelligent defrosting method for a refrigeration system according to claim 1 or 2, characterized in that: the intelligent defrosting method is provided with high-pressure and low-pressure alarm control, and when the high pressure or the low pressure exceeds the limit, the system outputs an alarm signal.
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| CN201911049427.XA CN110762915B (en) | 2019-10-31 | 2019-10-31 | Intelligent defrosting method of refrigeration system based on opening degree of electronic expansion valve |
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| CN201911049427.XA CN110762915B (en) | 2019-10-31 | 2019-10-31 | Intelligent defrosting method of refrigeration system based on opening degree of electronic expansion valve |
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| CN110762915B true CN110762915B (en) | 2021-03-19 |
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| CN112728854A (en) * | 2020-12-30 | 2021-04-30 | 天津华冷科技有限公司 | Intelligent defrosting method for refrigeration system based on evaporation temperature difference and refrigeration system |
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| JP2007010220A (en) * | 2005-06-30 | 2007-01-18 | Sanyo Electric Co Ltd | Refrigerating unit and refrigerator comprising the same |
| CN102374714A (en) * | 2011-11-09 | 2012-03-14 | 江苏天舒电器有限公司 | Control method for electronic expansion valve of heat-pump water heater and control device thereof |
| CN102654337A (en) * | 2012-05-09 | 2012-09-05 | 海尔集团公司 | Control method of electronic expansion valve in air conditioner |
| CN103438547A (en) * | 2013-09-23 | 2013-12-11 | 深圳麦克维尔空调有限公司 | Control method of electronic expansion valve |
| CN107606830A (en) * | 2017-09-05 | 2018-01-19 | 浙江正理生能科技有限公司 | A kind of electric expansion valve adjusting method |
| CN109612174A (en) * | 2018-12-12 | 2019-04-12 | 广东智科电子股份有限公司 | A kind of control method and its device of electric expansion valve |
| CN109990517A (en) * | 2019-04-15 | 2019-07-09 | 宁波工程学院 | Air conditioner intelligence quickly defrosting and protection control method |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3929067B2 (en) * | 2004-12-09 | 2007-06-13 | 松下電器産業株式会社 | heat pump |
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Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007010220A (en) * | 2005-06-30 | 2007-01-18 | Sanyo Electric Co Ltd | Refrigerating unit and refrigerator comprising the same |
| CN102374714A (en) * | 2011-11-09 | 2012-03-14 | 江苏天舒电器有限公司 | Control method for electronic expansion valve of heat-pump water heater and control device thereof |
| CN102654337A (en) * | 2012-05-09 | 2012-09-05 | 海尔集团公司 | Control method of electronic expansion valve in air conditioner |
| CN103438547A (en) * | 2013-09-23 | 2013-12-11 | 深圳麦克维尔空调有限公司 | Control method of electronic expansion valve |
| CN107606830A (en) * | 2017-09-05 | 2018-01-19 | 浙江正理生能科技有限公司 | A kind of electric expansion valve adjusting method |
| CN109612174A (en) * | 2018-12-12 | 2019-04-12 | 广东智科电子股份有限公司 | A kind of control method and its device of electric expansion valve |
| CN109990517A (en) * | 2019-04-15 | 2019-07-09 | 宁波工程学院 | Air conditioner intelligence quickly defrosting and protection control method |
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