CN108692497B - reliable oil return method of air conditioning system - Google Patents
reliable oil return method of air conditioning system Download PDFInfo
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- CN108692497B CN108692497B CN201810530854.9A CN201810530854A CN108692497B CN 108692497 B CN108692497 B CN 108692497B CN 201810530854 A CN201810530854 A CN 201810530854A CN 108692497 B CN108692497 B CN 108692497B
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- oil return
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- pressure
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- 238000004378 air conditioning Methods 0.000 title claims abstract description 26
- 238000000034 method Methods 0.000 title claims abstract description 26
- 238000001514 detection method Methods 0.000 claims description 9
- 238000006243 chemical reaction Methods 0.000 claims description 4
- 230000001186 cumulative effect Effects 0.000 claims description 4
- 238000009825 accumulation Methods 0.000 claims description 3
- 238000005336 cracking Methods 0.000 claims description 3
- 230000007774 longterm Effects 0.000 abstract description 2
- 239000003921 oil Substances 0.000 description 73
- 239000003507 refrigerant Substances 0.000 description 10
- 230000007423 decrease Effects 0.000 description 3
- 239000007788 liquid Substances 0.000 description 3
- 239000010687 lubricating oil Substances 0.000 description 3
- 230000002159 abnormal effect Effects 0.000 description 2
- 239000002826 coolant Substances 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 239000010729 system oil Substances 0.000 description 2
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 235000003642 hunger Nutrition 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 238000005057 refrigeration Methods 0.000 description 1
- 230000037351 starvation Effects 0.000 description 1
- 230000002459 sustained effect Effects 0.000 description 1
- 238000010977 unit operation Methods 0.000 description 1
Classifications
-
- 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
- F25B43/00—Arrangements for separating or purifying gases or liquids; Arrangements for vaporising the residuum of liquid refrigerant, e.g. by heat
- F25B43/02—Arrangements for separating or purifying gases or liquids; Arrangements for vaporising the residuum of liquid refrigerant, e.g. by heat for separating lubricants from the refrigerant
-
- 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
- F25B31/00—Compressor arrangements
- F25B31/002—Lubrication
- F25B31/004—Lubrication oil recirculating arrangements
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Mechanical Engineering (AREA)
- Thermal Sciences (AREA)
- General Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Power Engineering (AREA)
- Air Conditioning Control Device (AREA)
Abstract
The invention discloses a reliable oil return method of an air conditioning system. The method comprises the following steps: the air conditioning unit starts to accumulate the running time, when the accumulated running time reaches t1 or the long-term running accumulated time of the unit under the low-frequency f1 reaches t2, the unit reaches an oil return condition, at the moment, the air conditioning system detects the running ambient temperature, the running high and low pressure and the currently running program of the unit external unit, comprehensively judges the current running state of the system according to the running parameters of the unit, and selects different oil return logics. The oil return method of the air conditioning system can perform selective oil return according to different unit states, and ensures the oil return and the operation reliability of the unit.
Description
Technical field
The present invention relates to field of air conditioning, and in particular to a kind of reliable oil return method of air-conditioning system.
Background technique
Air-conditioning system in operation, the problem of system oil return can be related to, the especially system in seperated captain's connecting tube, than
Such as multi-line system, oil return demand can be more obvious.Air-conditioning system oil return logical design is primarily to prevent compression captain
Under phase low-frequency operation, outer machine and interior machine connecting tube are longer, the lubricating oil in system since the movement of refrigerant is taken out of inside compressor,
Oil starvation inside compressor is caused to cause compressor inordinate wear.
General oil return method is based on timing raising frequency oil return, and accumulation runs to certain time or low after compressor booting
After a certain period of time, unit executes oil return logic for frequency operation, and compressor improves running frequency, and electric expansion valve tunes up oil return and opens
Degree, takes back compressor for the lubricating oil inside connecting tube using the refrigerant of high speed.
Timing raising frequency oil return method is relatively simple, is easy to run, and mainly the time of detection unit operation and frequency carry out
Relevant action, but this oil return method is likely to encounter following problems:
1, when unit local environment temperature is higher or blockage of condenser, pressure at expulsion is higher, if unit continues to execute
Raising frequency, it is easy to unit be caused high voltage protective occur；
2, the long-term ultralow temperature operation heating of unit, pressure of inspiration(Pi) is lower, and the electric expansion valve of unit should keep certain aperture,
Electronic expansion valve opening is adjusted again when system pressure is higher or tends towards stability, if carrying out raising frequency oil return at this time, electronics is swollen
Swollen valve is opened greatly, is easy to lead to unit pressure of inspiration(Pi) dramatic decrease, unit is caused low-voltage variation occur；
3, there is oil return demand in Unit Low defrost, if having executed defrost, after unit switchs to heating operation from refrigeration
Oil return is carried out immediately, and since the unit refrigerant suction end degree of superheat is not completely set up at this time, compressor carries out raising frequency suddenly at this time and returns
Oil, it is easy to cause compressor liquid hammer.
Summary of the invention
In order to solve above-mentioned problems of the prior art, the present invention provides a kind of reliable oil return side of air-conditioning system
Method.
The technical solution adopted by the invention is as follows:
The reliable oil return method of air-conditioning system includes the following steps: that air-conditioner set booting starts Cumulative Elapsed Time, when tired
When the plot operation time reaches t1 or unit is when longtime running accumulated time reaches t2 at Frequency f1, and unit reaches back
Deep-fried twisted dough sticks part, the environment temperature of the outer machine operation of the unit of air-conditioning system detection at this time, the high-low pressure of operation and the program currently run,
According to unit operating parameter comprhensive deterministic system current operating conditions, different oil return logics is selected.
Further, as the high pressure >=P1 for the system that detects, and continuous operation certain time, at this time unit cancels oil return
Flag bit, without oil return, unit preferentially carries out limit down conversion process.If detected after unit limits frequency reducing operation a period of time
The high-pressure of unit system when being less than or equal to circumstance temperature T1 still >=P4, then it is dirty stifled to judge that set heat exchange device surface generates, at this time
Oil return is not executed, unit continues to run according to the frequency under current limit frequency reducing；Detect that unit is being higher than after unit limits frequency reducing
When system pressure drops below preset oil return cracking pressure P4 in circumstance temperature T1, judging unit, state is normal at this time, executes back
Oil operation.
Further, as the low pressure≤P2 for the system that detects, and continuous operation a period of time, system pressure is not also at this time
It establishes completely, is not suitable for oil return operation, the low frequency that unit keeps current continues to run.When the low pressure for the system that detects is more than
When preset oil return low pressure P3, judge that system pressure establishes normal, execution oil return operation.
Further, when the system that detects executes defrost program, when defrost frequency f2 >=preset oil return frequency f, at this time
Defrost be oil return, unit cancels oil return flag bit, accumulates the oil return time again, executes defrost program.When detecting defrost
When the preset oil return frequency f of frequency f2 <, defrost program has preferentially been executed, has then accumulated operation again after a certain period of time, detection is simultaneously
Calculate unit suction end suction superheat at this time, when unit suction superheat is than preset degree of superheat T high, judge system this
When the degree of superheat establish normal, unit executes oil return operation.
The oil return method of air-conditioning system of the present invention, it is contemplated that the different operating conditions that air-conditioning is likely encountered in actual operation are led to
It crosses logical program and judges operating status under the conditions of unit meets oil return, carry out selective oil return for different set states,
The oil return and operational reliability for ensuring unit avoid existing system using single circuit and do not consider that actual motion goes out
System protection problem caused by existing abnormal, abnormal oil return.
Detailed description of the invention
Fig. 1 is the flow chart of the method for the present invention.
In figure, f: the preset oil return frequency of unit, f1: the preset running frequency for opening oil return accumulated time of unit, f2:
Unit defrost frequency, t1: unit booting operation accumulated time, t2: the runing time accumulated when unit low frequency, P1: unit is default
High-pressure, P2: the preset low pressure of unit, P3: the preset system low-voltage pressure value for opening oil return program of unit,
P4: unit limits preset high-pressure after frequency reducing, T1: preset for judging the circumstance temperature of set state after unit limit frequency reducing, T:
The current suction superheat of unit.
Specific embodiment
To make the object, technical solutions and advantages of the present invention clearer, below in conjunction with attached drawing to embodiment party of the present invention
Method is described in further detail.
As shown in Figure 1, the unit of air-conditioning system Cumulative Elapsed Time after powering on booting, when one timing of unit accumulation operation
Between t1 when or unit when longtime running accumulated time reaches t2 at Frequency f1, unit reaches oil return condition, at this time system
Detection unit outer ring temperature runs high-low pressure and has currently run program, according to unit operating parameter comprehensive descision operating status, and
Carry out corresponding selective oil return.Wherein, t1 is to force the oil return time, for example run 100h etc., when reaching pressure oil return
Between, no matter whether unit is chronically at low frequency or high frequency belongs to reach oil return condition.The purpose for forcing oil return is mainly anti-
Only unit longtime running is unsatisfactory for the logic of oil return, does not carry out oil return operation for a long time.What Frequency f1 herein was referred mainly to
Frequency, such as 20hz-40Hz similar in Range compress machine running frequency lower limit, this quefrency be mainly unit operating parameter away from
It is run when close from setting value, so that operating parameter slowly close to setting value and keeps longtime running state.Run low frequency
Refer mainly to the frequency of non-longtime running state.Accumulated time t2 can be 6h, and system capability is larger, the shorter system of connecting tube
10h etc. can be extended to.
The specific logic judgment of the present embodiment and execution oil return operation are as follows:
When detecting system high pressure >=P1, and when continuous operation certain time, it is possible to the running environment of outdoor machine of air-conditioner
It is in blocked state in high temperature or set heat exchange device, is not appropriate for carrying out raising frequency oil return operation at this time, unit is easy to appear height
Pressure protection, therefore cancel oil return flag bit, i.e., at this time although system meets oil return, but when cancelling the statistics under low-frequency operation
Between, first not oil return, unit preferentially carries out limit down conversion process.Such as R410a coolant system, the maximum pressure of operation is about
4.2Mpa, when detecting system high pressure is 3.9MPa, and continuous service 30min, it was demonstrated that high pressure at this time is not even
The state of right property, but systems stay is in high pressure conditions, then unit carries out limit down conversion process.After unit generally limits frequency reducing, it is
Unite high pressure also can and then decline, if unit limit frequency reducing operation a period of time (such as 1H) after, detect unit be in circumstance temperature T1 with
The high-pressure of lower system still >=P4, such as outer ring T1 be 37 DEG C in the case where, the high pressure of unit still it is lower than 3.9MPa not
How much, for example pressure P4 value is 3.5MPa, it was demonstrated that the heat exchanger heat exchange of unit at this time is simultaneously bad, so pressure can not effectively drop
Go down.This is possible to set heat exchange device surface and generates dirty stifled, and unit not can be carried out voluntarily handle at this time, and air conditioning unit panel is aobvious
Show that device can prompt heat exchanger dirty stifled, do not execute oil return operation, unit continues to run according to the frequency under current limit frequency reducing, only when
After user notices that display board prompts heat exchanger is dirty to block up, the tamper of heat exchanger surface is understood, under the pressure drop of system at this time
After coming, oil return logic arranged side by side can be just executed, i.e., detects unit system pressure in being higher than circumstance temperature T1 after unit limits frequency reducing
When dropping below preset oil return cracking pressure P4, it is believed that state is normal at this time for unit, executes oil return；If user is always not
It is cleared up, then when system runs to pressure oil return condition according to limit frequency reducing, executes oil return operation.
When detecting system low-voltage≤P2, and continuous operation a period of time, it was demonstrated that system is likely to be at low circumstance temperature at this time
Or the state being just switched on is powered on, system pressure is not set up also completely, is not suitable for oil return operation, and the low frequency that unit keeps current continues
Operation.When system detection to low pressure is more than preset oil return low pressure P3, it is believed that system pressure is established normally, is held
Row oil return logic, avoids the occurrence of low-voltage variation caused by raising frequency.Pressure P3 herein is the pressure for normally meeting oil return logic, P2
There are 500KPa, low pressure for the pressure value for approaching low-voltage variation, such as the normal work pressure of inspiration(Pi) of R410a coolant system at low temperature
Pressure when protection is set as 200KPa, if the rigid boot system stability of unit is not set up, pressure may have 300KPa, when
When system detection is to low pressure P2≤300KPa, being not suitable for raising frequency at this time and carry out oil return, it should sustained continuous runs 30Min,
After each component, system stablize after, pressure reach service pressure P3 be 500KPa when, just progress oil return operation, prevent unit
Since frequency rises too fast too high, causes the pressure at compressor air suction end to decline and cause low-voltage variation.
When the system that detects executes defrost program, when defrost frequency f2 >=preset oil return frequency f, defrost at this time is
Oil return, unit cancel oil return flag bit, accumulate the oil return time again, execute defrost program.
As system detection oil return frequency f preset to defrost frequency f2 <, defrost logic, execution have preferentially been executed
Operation 30min is accumulated after white logic again, mainboard detects and calculates the suction superheat of unit suction end at this time (degree of superheat is current
Refrigerant saturation temperature difference under suction temperature and current pressure of inspiration(Pi)), when unit suction superheat is than preset degree of superheat T high
When, it is believed that system at this time establish normally by the degree of superheat, and unit executes oil return operation, avoids the occurrence of compressor liquid hit phenomenon.System mistake
Temperature is primarily to prevent refrigerant band liquid, when refrigerant has certain degree of superheat, it was demonstrated that refrigerant temperature at this time is full higher than this
With the refrigerant temperature under pressure, refrigerant is full gaseous state, and general degree of superheat demand is 2-3 DEG C, and the too high degree of superheat can cause to press
Contracting machine excessive discharge temperature, compressor power consumption increase.
If unit is unsatisfactory for above-mentioned all detection decision logics, that is, think that unit operates normally, according to itself
Normal oil return logic carries out oil return, mainly includes that compressor will do it raising frequency operation, frequency is increased to oil return frequency, utilizes height
Lubricating oil in pipeline is taken back compressor etc. by the refrigerant of speed flowing.
Claims (7)
1. the reliable oil return method of air-conditioning system, which comprises the steps of:
Air-conditioner set booting starts Cumulative Elapsed Time, and when Cumulative Elapsed Time reaches t1 or unit is in Frequency f1
When lower longtime running accumulated time reaches t2, unit reaches oil return condition, the ring of the outer machine operation of the unit of air-conditioning system detection at this time
Border temperature, the high-low pressure of operation and the current program run, currently run shape according to unit operating parameter comprhensive deterministic system
State selects different oil return logics；As the high pressure >=P1 for the system that detects, and continuous operation certain time, unit takes at this time
Disappear oil return flag bit, and without oil return, unit preferentially carries out limit down conversion process.
2. the reliable oil return method of air-conditioning system according to claim 1, which is characterized in that if unit limit frequency reducing operation
After a period of time, detect unit be less than or equal to circumstance temperature T1 when system high-pressure still >=P4, then judge set heat exchange device
Surface generation is dirty stifled, does not execute oil return at this time, and unit continues according to the frequency operation under current limit frequency reducing；After unit limits frequency reducing
Detect that unit when dropping below preset oil return cracking pressure P4 higher than system pressure in circumstance temperature T1, judges unit at this time
State is normal, executes oil return operation.
3. the reliable oil return method of air-conditioning system according to claim 2, which is characterized in that set heat exchange device surface generates
When dirty stifled, air conditioning unit panel display can issue warning note.
4. the reliable oil return method of air-conditioning system according to claim 1, which is characterized in that when the low pressure for the system that detects
≤ P2, and continuous operation a period of time, system pressure is not set up also completely at this time, is not suitable for oil return operation, and unit keeps working as
Preceding low frequency continues to run.
5. the reliable oil return method of air-conditioning system according to claim 4, which is characterized in that when the low pressure for the system that detects
When pressure is more than preset oil return low pressure P3, judge that system pressure establishes normal, execution oil return operation.
6. the reliable oil return method of air-conditioning system according to claim 1, which is characterized in that when detecting system execution
White program, when defrost frequency f2 >=preset oil return frequency f, defrost at this time is oil return, and unit cancels oil return flag bit, weight
The new accumulation oil return time, execute defrost program.
7. the reliable oil return method of air-conditioning system according to claim 6, which is characterized in that when detecting defrost frequency f2
When the preset oil return frequency f of <, defrost program has preferentially been executed, has then accumulated operation again after a certain period of time, has been detected and computer
The suction superheat of group suction end at this time judges that system overheats at this time when unit suction superheat is than preset degree of superheat T high
Degree establishes normal, unit execution oil return operation.
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| CN108692497B true CN108692497B (en) | 2019-12-03 |
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Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN109405216B (en) * | 2018-10-30 | 2021-03-23 | 广东美的暖通设备有限公司 | Oil return control method and system of air conditioner and air conditioner |
| CN109539632B (en) * | 2018-11-28 | 2019-10-01 | 珠海格力电器股份有限公司 | Oil return control method and device, storage medium and air conditioner |
| CN110131840B (en) * | 2019-05-15 | 2021-05-14 | 宁波奥克斯电气股份有限公司 | Oil return control method for variable frequency air conditioner and variable frequency air conditioner |
| CN110726274A (en) * | 2019-10-12 | 2020-01-24 | 珠海格力电器股份有限公司 | Oil return method of capillary network system |
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| CN105371531A (en) * | 2015-11-30 | 2016-03-02 | 珠海格力电器股份有限公司 | Low-frequency oil return control method and system of air conditioner |
| JP2018059663A (en) * | 2016-10-05 | 2018-04-12 | 三菱重工サーマルシステムズ株式会社 | Controller, refrigerant circuit system, control method and program |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US9732999B2 (en) * | 2014-03-21 | 2017-08-15 | Bosch Automotive Service Solutions Inc. | System and method for recovering refrigerant |
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| CN104180563A (en) * | 2013-05-27 | 2014-12-03 | 珠海格力电器股份有限公司 | Oil return method for heating of multi-split air conditioning system |
| CN105371531A (en) * | 2015-11-30 | 2016-03-02 | 珠海格力电器股份有限公司 | Low-frequency oil return control method and system of air conditioner |
| JP2018059663A (en) * | 2016-10-05 | 2018-04-12 | 三菱重工サーマルシステムズ株式会社 | Controller, refrigerant circuit system, control method and program |
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