CN108692497A - The reliable oil return method of air-conditioning system - Google Patents
The reliable oil return method of air-conditioning system Download PDFInfo
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- CN108692497A CN108692497A CN201810530854.9A CN201810530854A CN108692497A CN 108692497 A CN108692497 A CN 108692497A CN 201810530854 A CN201810530854 A CN 201810530854A CN 108692497 A CN108692497 A CN 108692497A
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- oil return
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Classifications
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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
- 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
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Mechanical Engineering (AREA)
- Thermal Sciences (AREA)
- General Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
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- Power Engineering (AREA)
- Air Conditioning Control Device (AREA)
Abstract
The invention discloses a kind of reliable oil return methods of air-conditioning system.This method comprises the following steps:Air-conditioner set booting starts Cumulative Elapsed Time, when Cumulative Elapsed Time reaches t1, or unit is when longtime running accumulated time reaches t2 at Frequency f1, unit reaches oil return condition, 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 current program run, judge system current operating conditions according to unit operation parametric synthesis, selects different oil return logics.The oil return method of air-conditioning system of the present invention can be directed to different set states and carry out selective oil return, it is ensured that the oil return of unit and operational reliability.
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 technology
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 apparent.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 accumulated after compressor is switched on based on timing raising frequency oil return and is run to certain time or low
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, compressor is taken back using the refrigerant of high speed by the lubricating oil inside connecting tube.
Timing raising frequency oil return method is relatively simple, is easy to run, and the time and frequency for mainly detecting unit operation carry out
Relevant action, but this oil return method is likely to encounter problems with:
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 relatively low, 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, unit is after refrigeration switchs to heating operation
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 and returns suddenly at this time
Oil, it is easy to cause compressor liquid hammer.
Invention content
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 present invention is as follows:
The reliable oil return method of air-conditioning system, includes the following steps: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 current program run,
Judge system current operating conditions according to unit operation parametric synthesis, selects different oil return logics.
Further, as the high pressure >=P1 for the system that detects, and continuous operation certain time, unit cancels oil return at this time
Flag bit, without oil return, unit preferentially carries out limit down conversion process.After if unit limits frequency reducing operation a period of time, detect
The high-pressure of unit system when 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;When unit limit frequency reducing after detect unit higher than
When system pressure drops below preset oil return Opening 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 with.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 the suction superheat of unit suction end 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 modes 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, selective oil return is carried out for different set states,
Oil return and the operational reliability for ensuring unit avoid existing system and do not consider that actual motion goes out using single circuit
System protection problem caused by existing abnormal, abnormal oil return.
Description of the drawings
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 run 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:The preset circumstance temperature for judging set state after unit limit frequency reducing, T:
The current suction superheat of unit.
Specific implementation mode
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 shroud temperature runs high-low pressure and has currently run program, judges operating status according to unit operation parametric synthesis, 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 operation 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 susceptible to 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 systems, the maximum pressure of operation is about
4.2Mpa, when it is 3.9MPa to detect system high pressure, 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 in the case where outer shroud T1 is 37 DEG C, the high pressure of unit still it is lower than 3.9MPa not
How much, for example pressure P4 values are 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 cannot have been handled voluntarily 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 higher than circumstance temperature T1 after unit limits frequency reducing
When dropping below preset oil return Opening 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 detectio 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
To approach the pressure value of low-voltage variation, as the normal work pressure of inspiration(Pi) of R410a coolant systems at low temperature has 500KPa, low pressure
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 detectio 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 detectio 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
Suction temperature and the refrigerant saturation temperature difference under 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 unit normal operation, according to itself
Normal oil return logic carries out oil return, and raising frequency operation can be carried out by including mainly compressor, and 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 (8)
1. the reliable oil return method of air-conditioning system, which is characterized in that include the following steps:
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, judge that system currently runs shape according to unit operation parametric synthesis
State selects different oil return logics.
2. the reliable oil return method of air-conditioning system according to claim 1, which is characterized in that when the high pressure for the system that detects
>=P1, and continuous operation certain time, at this time unit cancel oil return flag bit, without oil return, unit preferentially carries out limit drop
Frequency is handled.
3. the reliable oil return method of air-conditioning system according to claim 2, which is characterized in that if unit limit frequency reducing operation
After a period of time, detect the high-pressure of unit system when less than or equal to circumstance temperature T1 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 system pressure drops below preset oil return Opening pressure P4 in higher than circumstance temperature T1, judges unit at this time
State is normal, executes oil return operation.
4. the reliable oil return method of air-conditioning system according to claim 3, which is characterized in that set heat exchange device surface generates
When dirty stifled, air conditioning unit panel display can send out alarm.
5. 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, at this time system pressure do not set up also completely, be not suitable for oil return operation, unit keeps working as
Preceding low frequency continues to run with.
6. the reliable oil return method of air-conditioning system according to claim 5, 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.
7. 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.
8. the reliable oil return method of air-conditioning system according to claim 7, 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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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109405216A (en) * | 2018-10-30 | 2019-03-01 | 广东美的暖通设备有限公司 | Method for controlling oil return, system and the air conditioner of air conditioner |
| CN109539632A (en) * | 2018-11-28 | 2019-03-29 | 珠海格力电器股份有限公司 | A kind of method for controlling oil return, device, storage medium and air-conditioning |
| CN110131840A (en) * | 2019-05-15 | 2019-08-16 | 宁波奥克斯电气股份有限公司 | A kind of convertible frequency air-conditioner method for controlling oil return and convertible 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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| 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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