CN112880228A - Air conditioner liquid return prevention device and method for preventing air conditioner liquid return - Google Patents
Air conditioner liquid return prevention device and method for preventing air conditioner liquid return Download PDFInfo
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- CN112880228A CN112880228A CN202110140993.2A CN202110140993A CN112880228A CN 112880228 A CN112880228 A CN 112880228A CN 202110140993 A CN202110140993 A CN 202110140993A CN 112880228 A CN112880228 A CN 112880228A
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- 239000007788 liquid Substances 0.000 title claims abstract description 243
- 230000002265 prevention Effects 0.000 title claims abstract description 58
- 238000000034 method Methods 0.000 title claims abstract description 23
- 230000003405 preventing effect Effects 0.000 title claims abstract description 22
- 239000003507 refrigerant Substances 0.000 claims abstract description 100
- 238000010257 thawing Methods 0.000 claims abstract description 49
- 238000005057 refrigeration Methods 0.000 claims abstract description 23
- 238000001514 detection method Methods 0.000 claims description 7
- 230000002045 lasting effect Effects 0.000 claims description 4
- 238000010438 heat treatment Methods 0.000 abstract description 10
- 238000001816 cooling Methods 0.000 description 5
- 230000000694 effects Effects 0.000 description 3
- 239000013589 supplement Substances 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 238000001704 evaporation Methods 0.000 description 2
- 230000008020 evaporation Effects 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 239000011550 stock solution Substances 0.000 description 2
- 238000004378 air conditioning Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 238000009533 lab test Methods 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
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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
- F25B13/00—Compression machines, plants or systems, with reversible cycle
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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
- F25B43/006—Accumulators
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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
- 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
- F25B2500/00—Problems to be solved
- F25B2500/28—Means for preventing liquid refrigerant entering into the compressor
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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)
- Analytical Chemistry (AREA)
- Power Engineering (AREA)
- Air Conditioning Control Device (AREA)
Abstract
The invention provides an air conditioner liquid return prevention device and a method for preventing the air conditioner liquid return, wherein the liquid return prevention device comprises a four-way reversing valve, a solenoid valve, a liquid storage tank, a first throttle valve and four one-way valves, one end of the solenoid valve is connected with an outlet of the first one-way valve, the other end of the solenoid valve is connected with a g port of the four-way reversing valve, an h port of the four-way reversing valve is connected with a k port of the liquid storage tank, an m port of the liquid storage tank is connected with an i port of the four-way reversing valve, a j port of the four-way solenoid valve is connected with the first throttle valve, the first throttle valve is connected with inlets of a third one-way valve and a second one-way valve, an outlet of the fourth one-way valve is connected with the solenoid valve, an inlet of the first one-way valve and an outlet of the. Redundant refrigerants of the system can be stored in the liquid storage tank in a plurality of working states such as an air conditioner refrigeration low-load state, before heating defrosting and before heating defrosting, and the like, so that liquid return of the compressor is prevented.
Description
Technical Field
The invention belongs to the technical field of air conditioners, and particularly relates to an air conditioner liquid return prevention device and an air conditioner liquid return prevention method.
Background
When the air conditioner is defrosted, the condenser in operation is changed into the evaporator through the switching of the four-way valve, and the evaporator is changed into the condenser. When the condenser is suddenly changed into the evaporator, the amount of the refrigerant stored in the condenser is large, and liquid return of the compressor is easily caused. In the defrosting operation process of the system, when the quantity of circulating refrigerants is small, incomplete defrosting and long period are easily caused. When the amount of the circulating refrigerant is large, the refrigerant is not completely evaporated due to the low speed or the stop of the indoor side fan during defrosting, and the liquid return of the compressor during defrosting is easily caused. When the two devices are switched after defrosting is finished, liquid return of the pressing machine is easily caused.
When the air conditioner operates under low load, the liquid return of the press is easily caused due to insufficient indoor side evaporation.
According to the problems, a set of liquid return prevention device for the air conditioner is developed to avoid the liquid return phenomenon of the compressor during low load and defrosting of the air conditioner.
As shown in fig. 2 of the patent, during defrosting operation, according to a normal defrosting cycle, an indoor fan is closed, liquid refrigerant flows into an indoor unit 5, a control valve 6 is closed, a control valve 10 is opened, and the refrigerant directly flows back to a liquid storage tank 2 and returns to a press 1. The solution of this patent presents the following problems:
1) when the air conditioner operates under low load, the liquid return of the system cannot be prevented,
2) the system has no cold dissipation during defrosting, has poor defrosting effect,
3) the liquid storage tank has non-adjustable refrigerant quantity, is arranged on the suction side of the press, stores the refrigerant during the refrigeration and heating operation, has limited refrigerant quantity during the actual defrosting, still has the risk of liquid return,
4) after defrosting of the system is finished, the refrigerant in the liquid storage tank cannot be supplemented into the system.
Chinese patent (application No. 201410719839.0) discloses an air conditioner, which operates as follows:
in the defrosting mode I, three parallel cycles are adopted, as shown in the attached figure 3 of the patent, high-temperature and high-pressure gas refrigerant enters the outdoor heat exchanger 3 for heat exchange through the exhaust a of the compressor 1 through the reversing assembly 2, and is condensed into liquid refrigerant after the heat exchange is finished. The liquid refrigerant discharged from the outdoor heat exchanger 3 is divided into two paths, the first path is throttled into the refrigerant in a medium temperature and pressure state at one time by an electronic expansion valve 6 on a first flow path, and the refrigerant in the medium temperature and pressure state enters a flash evaporator 5 through a first interface h to be separated into two parts. The first part of refrigerant is secondarily throttled by the throttling component 7 on the second flow path to be in a low-temperature and low-pressure state and then enters the indoor heat exchanger 4 for heat exchange, and then is generated into gas after the heat exchange is finished, and the gas returns to the gas port b of the compressor 1 through the reversing component 2, and then is compressed into high-temperature and high-pressure gas to be discharged to enter the next cycle. The second part of the gas refrigerant separated from the flash evaporator 5 directly reaches the air supplement port c of the compressor 1 through the air supplement pipe 17 for air injection, is mixed with the gas compressed to a certain degree by the first part entering the air return port b, is compressed and then is discharged, and enters the next cycle. And a second path of liquid refrigerant discharged from the outdoor heat exchanger 3 enters the indoor heat exchanger 4 for heat exchange after being throttled by the control assembly 8 on the bypass loop, is evaporated into gas after heat exchange, returns to the air return port b of the compressor 1 through the reversing assembly 2, and is compressed into high-temperature and high-pressure gas to be discharged into the next cycle. In this mode, the control component 8 controls the bypass circuit to be opened, the bypass circuit is regarded as a third circulation, and at this time, the opening degrees of the first electronic expansion valve 6 and the throttling component 7 need to be controlled in a matching manner to be defrosting opening degrees.
And a second defrosting mode, namely, one-way circulation, as shown in the attached figure 4 of the patent, a high-temperature and high-pressure gas refrigerant enters the outdoor heat exchange 3 from an exhaust port a of the compressor 1 through the reversing assembly 2 to exchange heat, and is condensed into a liquid refrigerant after the heat exchange is finished. After being throttled by a control assembly 8 on a bypass loop, liquid refrigerant discharged from the outdoor heat exchanger 3 enters an indoor heat exchanger 4 for heat exchange, is evaporated into gas after heat exchange, returns to a return air port b of the compressor 1 through a reversing assembly 2, is compressed into high-temperature high-pressure gas, and is discharged into the next cycle. In this mode, the control unit 8 controls the bypass circuit to be open and the bypass circuit to be clear, and in this mode, the opening degrees of the first electronic expansion valve 6 and the throttle unit 7 are zero or small, and the flow rate is ignored with respect to the bypass circuit and is approximately regarded as cut-off. The patent scheme has the following problems:
1) the liquid return of the press cannot be prevented when defrosting is started and stopped,
2) during defrosting operation, no refrigerant storage equipment exists, the risk of liquid return still exists,
3) not applicable to non-air-jet presses.
Disclosure of Invention
The invention provides an air conditioner liquid return prevention device and a method for preventing the air conditioner liquid return, which solve the problems that the control effect is limited, and the liquid return of a press cannot be prevented when defrosting is started and finished and the air conditioner is in low-load operation when the existing air conditioner can only prevent the press liquid return when a system is defrosted.
The invention provides an air conditioner liquid return prevention device which comprises a four-way reversing valve, an electromagnetic valve, a liquid storage tank, a first throttling valve and four one-way valves, one end of the electromagnetic valve is connected with the outlet of the first one-way valve, the other end of the electromagnetic valve is connected with the g port of the four-way reversing valve, the h port of the four-way reversing valve is connected with the k port of the liquid storage tank, the m port of the liquid storage tank is connected with the i port of the four-way reversing valve, the j port of the four-way electromagnetic valve is connected with a first throttle valve, the first throttle valve is connected with the inlets of a third one-way valve and a second one-way valve, the outlet of the fourth one-way valve is connected with the electromagnetic valve, the inlet of the first one-way valve and the outlet of the second one-way valve are connected with one end of a second throttle valve on a refrigerant pipeline between outdoor heat exchange and indoor heat exchange of the air conditioner, and the outlet of the third one-way valve and the inlet of the fourth one-way valve are connected to the other end of the second throttling valve on the refrigerant pipeline between the outdoor heat exchange and the indoor heat exchange of the air conditioner.
The invention also provides a method for preventing the air conditioner from returning liquid, which comprises the following steps: detecting that the air conditioner is in a low-load refrigeration state, enabling the air conditioner liquid return prevention device to enter a liquid storage mode, starting a solenoid valve of the air conditioner liquid return prevention device, and storing redundant refrigerants of the system into a liquid storage tank; detecting that the air conditioner runs in a refrigeration high-load state, enabling the air conditioner liquid return prevention device to enter a liquid drainage mode, starting an electromagnetic valve and a four-way reversing valve of the air conditioner liquid return prevention device, and replenishing a refrigerant in a liquid storage tank into the system; when the condition that the air conditioner meets the defrosting control condition is detected, the air conditioner liquid return prevention device enters a liquid storage mode, a solenoid valve of the air conditioner liquid return prevention device is started, and redundant refrigerants of the system are stored in a liquid storage tank; when the air conditioner is detected to be in the defrosting state, the air conditioner liquid return prevention device is controlled to enter a liquid storage mode or a liquid discharge mode by judging the superheat degree of the indoor unit and the opening degree of a second throttle valve; when the air conditioner is detected to quit defrosting control, the air conditioner liquid return prevention device enters a liquid drainage mode, an electromagnetic valve and a four-way reversing valve of the air conditioner liquid return prevention device are opened, and a refrigerant in the liquid storage tank is replenished into the system.
The air conditioner in a refrigeration low-load state needs to simultaneously meet the following two opening conditions:
firstly, the actual superheat degree of an evaporator is less than a target set superheat degree and lasts for the first time;
and secondly, detecting that the valve opening degree is smaller than the first valve opening degree by the second throttle valve, and continuing for a second time.
Preferably, the air conditioner is operated in a refrigeration low-load state, and when the following optional conditions are met, the liquid return prevention device exits the liquid storage mode:
firstly, the actual superheat degree of an evaporator is larger than or equal to a target set superheat degree and lasts for a third time;
and the opening degree of the second throttle valve detection valve is larger than the opening degree of the second valve.
Preferably, the air conditioner is operated in a refrigerating high-load state, and the following two conditions are simultaneously met:
firstly, the actual superheat degree of an evaporator is larger than the target set superheat degree and lasts for a fourth time;
and secondly, detecting the valve opening degree of the second throttle valve is larger than the third valve opening degree, and continuing for the fifth time.
Preferably, the air conditioner is operated in a refrigeration high-load state, and when the following optional conditions are met, the liquid return prevention device exits the liquid storage mode:
firstly, the actual superheat degree of the evaporator is less than the target set superheat degree and lasts for the sixth time;
secondly, detecting the valve opening degree of the second throttle valve to be smaller than the fourth valve opening degree;
and thirdly, continuously operating the liquid discharge mode for the seventh time.
Preferably, the air conditioner is when defrosting the state operation, satisfies following three conditions simultaneously, and the liquid device is prevented returning by the air conditioner gets into the stock solution mode, and when arbitrary condition is unsatisfied, withdraws from the stock solution mode:
firstly, the superheat degree of an indoor unit is less than a first temperature;
secondly, detecting the valve opening smaller than the first valve opening by a second throttle valve;
and thirdly, lasting for the eighth time.
Preferably, when the air conditioner is operated in a defrosting state, the following three conditions are simultaneously met, the liquid return preventing device of the air conditioner enters the liquid drainage mode, and when any one condition is not met, the liquid drainage mode is exited:
firstly, the superheat degree of the indoor unit is higher than a second temperature;
secondly, the opening degree of the first throttle valve is larger than the opening degree of a third valve;
and thirdly, lasting for the ninth time.
In the method for preventing the liquid return of the air conditioner, the first valve opening is the minimum valve opening set by a system and can be changed according to actual test setting; the second valve opening is the minimum valve opening set by the system plus 10 steps and can be changed according to the actual test setting; the third valve opening is the maximum valve opening set by the system and can be changed according to the actual test setting; the fourth valve opening is the maximum valve opening set by the system minus 10 steps and can be changed according to actual test setting. The first temperature, the second temperature, the first time-the ninth time are adjusted according to the actual laboratory test conditions due to different models.
The invention has the beneficial effects that: the liquid return preventing device of the air conditioner can store redundant refrigerant of the system in the liquid storage tank in a plurality of working states of the air conditioner, such as a low-load state of refrigeration, before heating defrosting and the like, so that the liquid return preventing effect of the compressor is very obvious, and when the refrigerant quantity of the system is insufficient, the liquid return preventing device of the air conditioner can release the refrigerant in the liquid storage tank, so that the refrigeration and heating effects are not influenced.
Drawings
FIG. 1 is a system diagram of the liquid return preventing device of the air conditioner of the present invention;
FIG. 2 is a schematic view of the working state of the liquid return prevention device of the air conditioner in the low-load cooling operation state;
FIG. 3 is a schematic view of the working state of the liquid return prevention device of the air conditioner in the refrigeration high-load operation state;
FIG. 4 is a schematic view of the working state of the liquid return prevention device before heating and defrosting of the air conditioner of the present invention;
FIG. 5 is a schematic view of the working state of the liquid return prevention device after the air conditioner completes heating and defrosting according to the present invention;
fig. 6 is a schematic diagram of a method for preventing liquid return of an air conditioner according to the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and should not be construed as limiting the scope of the invention.
Examples
Referring to fig. 1, the embodiment provides a liquid return prevention device for an air conditioner, which includes a first four-way reversing valve 1, a solenoid valve 2, a liquid storage tank 3, a first throttle valve 4 and four check valves, wherein one end of the solenoid valve 2 is connected to an outlet of the first check valve 5, the other end of the solenoid valve 12 is connected to a port g of the first four-way reversing valve 1, a port h of the first four-way reversing valve 1 is connected to a port k of the liquid storage tank 3, a port m of the liquid storage tank 3 is connected to a port i of the first four-way reversing valve 1, a port j of the first four-way solenoid valve 1 is connected to the first throttle valve 4, the first throttle valve 4 is connected to inlets of a second check valve 6 and a third check valve 7, an outlet of the fourth check valve 8 is connected to the solenoid valve 2, an inlet of the first check valve 5 and an outlet of the second check valve 6 are connected to one end of a second throttle valve 11 on, the outlet of the third check valve 7 and the inlet of the fourth check valve 8 are connected to the other end of a second throttle valve 11 on a refrigerant pipeline between an outdoor heat exchanger 9 and an indoor heat exchanger 10 of the air conditioner. The air conditioner shown in fig. 1 further includes a second four-way selector valve 12, a compressor 13, an indoor and outdoor unit connection liquid pipe operation valve 14, and an indoor and outdoor unit connection air pipe operation valve 15.
In this embodiment, when the valve body of the first four-way reversing valve 1 is not energized, the ports g and h are connected, and the ports j and i are connected, and when the valve body is energized, the ports g and i are connected, and the ports h and j are connected. When the valve body of the second four-way reversing valve 12 is not electrified, the ports c and d are communicated, the ports e and f are communicated, and when the valve body is electrified, the ports c and e are communicated, and the ports d and f are communicated. In the embodiment, a k interface pipeline of the liquid storage tank 3 is communicated to the bottom of the liquid storage tank 3, an m interface pipeline is communicated to the top of the liquid storage tank 3, the liquid storage tank 3 has directionality, and when the liquid flows in from the k interface and flows out from the m interface, the liquid storage mode is adopted, and liquid refrigerants can be stored; when the refrigerant flows into the k interface from the m interface and flows out from the k interface, the liquid storage tank does not store the liquid, and the liquid refrigerant is taken away by the k interface pipeline, so that the liquid discharge mode is realized.
Referring to fig. 2, when the air-conditioning cold low-load state is in operation, the second four-way selector valve 12 is not energized, the solenoid valve 2 is in an open state, and the first four-way selector valve 1 is not energized.
Because the indoor side refrigerant is not completely evaporated in low load, the refrigerant at the return air port b of the compressor 13 is ensured to be gaseous by storing redundant refrigerant into the liquid storage tank 3.
The process is as follows:
the high temperature and high pressure gas refrigerant compressed by the compressor 13 flows from the air exhaust port a of the compressor 13, flows through the ports c and d of the second four-way reversing valve 12, flows into the outdoor heat exchanger 9, is condensed and then becomes high pressure liquid, the liquid refrigerant is divided into two paths, the first path is throttled by the second throttling valve 11 and becomes low temperature liquid, enters normal circulation, the second path flows through the fourth one-way valve 8, the electromagnetic valve 2, flows into the port g of the first four-way reversing valve 1, flows out from the port h, enters the liquid storage tank 3, enters the port k of the liquid storage tank 3, flows out from the port m, the liquid storage tank 3 stores part of the liquid refrigerant, the redundant liquid refrigerant flows to the port i of the first four-way reversing valve 1, flows out from the port j, enters the first throttling valve 4, is throttled and becomes low temperature liquid refrigerant, is mixed with the first path of refrigerant after passing through the second one-way valve 6, enters the indoor heat, the air pipe operation valve 15 and the f port and the e port of the second four-way reversing valve 12 are connected through the internal and external machines and return to the return air port b of the compressor 13, and the air pipe operation valve and the f port and the e port are compressed by the compressor 13 and then enter the next cycle.
When the air conditioner is in a low-load refrigeration state, the liquid return prevention device of the air conditioner acts to store redundant refrigerants in the liquid storage tank 3.
When the refrigeration is in low-load operation, part of refrigerant is stored in the liquid storage tank 3, when the indoor and outdoor loads are changed from low load to high load, the refrigerant in the liquid storage tank 3 needs to be released when the operation refrigerant quantity of the system (without the refrigerant in the liquid storage tank) cannot meet the operation requirement, at the moment, the second four-way reversing valve 12 is not electrified, the electromagnetic valve 2 is in an open state, and the first four-way reversing valve 1 is electrified for reversing.
Referring to fig. 3, the flow is as follows:
the high temperature and high pressure gas refrigerant compressed by the compressor 13 flows from the air exhaust port a of the compressor 13, flows through the ports c and d of the second four-way reversing valve 12, flows into the outdoor heat exchanger 9, is condensed and then becomes high pressure liquid, the liquid refrigerant is divided into two paths, the first path is throttled by the second throttling valve 11 and becomes low temperature liquid, enters normal circulation, the second path flows through the fourth one-way valve 8, the electromagnetic valve 2, flows into the port g of the first four-way reversing valve 1, flows out from the port i, enters the liquid storage tank 3, enters the port m of the liquid storage tank 3, flows out from the port k, takes away the liquid refrigerant stored in the liquid storage tank 3, flows out from the liquid storage tank 3 to the port h of the first four-way reversing valve 1, flows out from the port j, enters the first throttling valve 4, is throttled and becomes low temperature liquid refrigerant, is mixed with the first path of refrigerant after passing through the second one-way valve 6, the air pipe operation valve 15 and the f port and the e port of the second four-way reversing valve 12 are connected through the internal and external machines and return to the return air port b of the compressor 13, and the air pipe operation valve and the f port and the e port are compressed by the compressor 13 and then enter the next cycle.
When the air conditioner exits from the refrigeration low-load state and operates in a high-load state, the liquid return prevention device of the air conditioner acts to supplement the refrigerant in the liquid storage tank 3 into the system circulation.
When the system is defrosted, the condenser in operation is changed into the evaporator, and the evaporator is changed into the condenser. When the condenser is suddenly changed into the evaporator, the quantity of the refrigerant reserved in the condenser is large, liquid return is easily caused, and in order to avoid the situation, when the condition that the system needs defrosting is detected, the electromagnetic valve 2 is opened, the liquid refrigerant in the indoor unit is stored in the liquid storage tank 3, and liquid return during switching is prevented. At this time, the second four-way selector valve 12 is energized and switched, the solenoid valve 2 is in an open state, and the first four-way selector valve 1 is not energized.
The process is as follows:
referring to fig. 4, the high-temperature and high-pressure gaseous refrigerant compressed by the compressor 13 flows from the exhaust port a of the compressor 13 through the ports c and e of the second four-way reversing valve 12, flows into the indoor heat exchanger 10 through the indoor and outdoor unit connecting air pipe operation valve 15, is condensed into a high-pressure liquid, flows into the outdoor unit through the indoor and outdoor unit connecting liquid pipe operation valve 14, is divided into two paths, the first path is throttled by the second throttle valve 11, is throttled into a low-temperature liquid, flows into the outdoor heat exchanger 9, the second path flows into the first one-way valve 5, flows into the g port of the first four-way reversing valve 1 through the solenoid valve 2, flows out of the h port, flows into the liquid storage tank 3, flows into the k port and the m port of the liquid storage tank 3, stores the liquid refrigerant, the surplus liquid refrigerant flows to the i port of the first four-way reversing valve 1, flows out of the j port, flows into the first throttle valve 4, is, enters the outdoor heat exchanger 9, is changed into a low-temperature gas state after heat exchange, returns to the air return port b of the compressor 13 through the port d and the port f of the second four-way reversing valve 12, and enters the next cycle after being compressed by the compressor 13. At the moment, the refrigerant in the system condenser is stored in the liquid storage tank 3, and the liquid return of the system cannot be caused when the second four-way reversing valve 12 reverses.
When the system is in defrosting operation, if the quantity of refrigerants circulating in the two heat exchangers is too small, the defrosting of the outdoor heat exchanger is easy to slow; if the refrigerant quantity of the internal circulation of the two heat exchangers is large, the liquid return of an incomplete evaporation system is easily caused due to the fact that an indoor fan stops rotating or the rotating speed is low during defrosting, and at the moment, the refrigerant quantity of the system needs to be controlled and adjusted.
After the liquid return prevention device is installed, the amount of refrigerant circulating in the two heat exchangers of the system can be adjusted by whether the first four-way reversing valve 1 is opened or not.
When the quantity of the circulating refrigerant in the system is insufficient and the refrigerant needs to be supplemented, the system operation state and the refrigeration operation state are changed from a low load to a high load, namely as shown in fig. 3, and the refrigerant circulating process shown in fig. 3 is not repeated herein;
when the amount of the circulating refrigerant in the system is excessive and the liquid storage tank 3 needs to store the refrigerant, the system operation state is the same as the refrigeration low-load operation state, namely as shown in fig. 2, and the refrigerant circulating process shown in fig. 2 is not repeated here;
the difference between the two states is the energization of the first four-way selector valve 1.
When the system defrosting is detected to be stopped, in order to prevent outdoor heat exchange after the second four-way reversing valve 12 is reversed, the liquid refrigerant in the refrigerant tank 9 directly returns to the compressor 13, so that the liquid refrigerant returns to the compressor, redundant refrigerant needs to be stored in the liquid storage tank 3, and the operation state is the same as the refrigeration low-load operation state, which is shown in fig. 2, and the refrigerant circulation process shown in fig. 2 is not repeated here.
When the system finishes defrosting, the liquid refrigerant in the liquid storage tank 3 needs to be supplemented into the system, the heating capacity of the system is improved, and the operation flow is shown in fig. 5: at this time, the second four-way selector valve 12 is energized to change the direction, the solenoid valve 2 is in an open state, and the first four-way selector valve 1 is energized to change the direction.
The system operation flow comprises the following steps:
when the defrosting of the system is detected to be finished, the electromagnetic valve 2 is opened, the high-temperature and high-pressure gaseous refrigerant compressed by the compressor 13 flows through the ports c and e of the second four-way reversing valve 12 from the exhaust port a of the compressor 13, flows into the indoor heat exchanger 10 through the indoor and outdoor machine connecting air pipe operation valve 15, is changed into high-pressure liquid after being condensed, enters the outdoor machine through the indoor and outdoor machine connecting liquid pipe operation valve 14, is divided into two paths, the first path is throttled by the second throttling valve 11, is changed into low-temperature liquid after being throttled, enters the outdoor heat exchanger 9, enters the first one-way valve 5, enters the port g of the first four-way reversing valve 1 through the electromagnetic valve 2, flows out from the port i, enters the liquid storage tank 3, enters the port m and the port k of the liquid storage tank 3, takes the liquid refrigerant in the liquid storage tank 3 away, flows to the port h of the first four-way reversing valve, the refrigerant is mixed with the first path of refrigerant after passing through the third one-way valve 7, enters the outdoor heat exchanger 9, is changed into a low-temperature gas state after heat exchange, returns to the air return port b of the compressor 13 through the ports d and f of the second four-way reversing valve 12, and enters the next cycle after being compressed by the compressor 13. At this time, the liquid refrigerant stored in the receiver 3 is replenished into the system.
The embodiment also provides a method for preventing the liquid return of the air conditioner, and with reference to fig. 6, the method includes: detecting that the air conditioner is in a low-load refrigeration state, enabling the air conditioner liquid return prevention device to enter a liquid storage mode, starting a solenoid valve 2 of the air conditioner liquid return prevention device, and storing redundant refrigerants of the system into a liquid storage tank 3; when the air conditioner is detected to be in a refrigerating high-load state, the air conditioner liquid return prevention device enters a liquid drainage mode, the electromagnetic valve 2 and the first four-way reversing valve 1 of the air conditioner liquid return prevention device are opened, and the refrigerant in the liquid storage tank 3 is replenished into the system.
When the condition that the air conditioner meets the defrosting control condition is detected, the air conditioner liquid return prevention device enters a liquid storage mode, the electromagnetic valve 2 of the air conditioner liquid return prevention device is opened, and redundant refrigerants of the system are stored in the liquid storage tank 3. In order to avoid the situation that the system meets the defrosting condition and needs to enter defrosting, the second four-way reversing valve 12 is directly switched to cause liquid return, and when the system meets the defrosting condition, the refrigerant running in the system is stored in the liquid storage tank 3 firstly, namely, the liquid storage mode of the liquid return prevention device is entered.
And after detecting that the outlet of the indoor unit is overheated (the outlet temperature is higher than the saturated pressure temperature) or runs for 2min, switching the second four-way reversing valve 12 and entering the conventional defrosting control. When the air conditioner is detected to be in the defrosting state, the air conditioner liquid return prevention device is controlled to enter a liquid storage mode or a liquid drainage mode by judging the superheat degree of the indoor unit and the opening degree of the second throttle valve 11.
When the air conditioner is detected to quit defrosting control, the air conditioner liquid return prevention device enters a liquid drainage mode, the electromagnetic valve 2 and the first four-way reversing valve 1 of the air conditioner liquid return prevention device are opened, and the refrigerant in the liquid storage tank 3 is replenished into the system. And then, after detecting that the outlet of the outdoor unit is overheated (the outlet temperature is higher than the saturation pressure temperature) or operates for 2min, switching the first four-way reversing valve 1 to enter normal heating operation.
After the first four-way reversing valve 1 is switched, the liquid return prevention device enters a liquid drainage mode, the operation is carried out for 10min, after 10min, the liquid return prevention device enters a closed state, the refrigerant in the liquid storage device 3 is replenished into the system, and the heating performance of the system is improved.
As a preferred embodiment of the present embodiment, the second throttle 11 is an electronic expansion valve. Of course, the second throttle 11 may be other throttle, such as a capillary tube, which has a poor flow regulation capability and is more likely to generate liquid return.
As a preferred implementation manner of this embodiment, the operation of the air conditioner in the cooling low load state needs to satisfy the following two opening conditions at the same time:
firstly, the actual superheat degree of an evaporator is less than the target set superheat degree and lasts for 5 min;
and the opening of the detection valve of the second throttle valve 11 is less than 90 and lasts for 5 min.
When the first throttle valve 11 is closed to the set lower limit, the actual superheat degree of the evaporator is still lower than the target superheat degree, which indicates that the continuous operation may cause liquid return of the system due to excessive refrigerant in the system, and in order to avoid the hidden danger of liquid return, the liquid storage mode of the liquid return prevention device is started to store the liquid refrigerant of the system.
As a preferred embodiment of this embodiment, the air conditioner is operated in a cooling low-load state, and the liquid return prevention device exits the liquid storage mode when any of the following conditions is met:
firstly, the actual superheat degree of an evaporator is more than or equal to a target set superheat degree and lasts for 2 min;
and the opening of the detection valve of the second throttle valve 11 is more than 100.
As a preferred implementation manner of this embodiment, the operation of the air conditioner in the cooling high load state needs to satisfy the following two conditions at the same time:
firstly, the actual superheat degree of an evaporator is larger than the target set superheat degree and lasts for 5 min;
and secondly, detecting the valve opening degree of more than 450 by the second throttle valve 11 for 5 min.
When the first throttle valve 11 is opened to the set upper limit, the actual superheat degree of the evaporator is still higher than the target superheat degree, which indicates that the refrigerant in the system is too little and the refrigerating capacity of the system is insufficient, and at this time, the stored refrigerant needs to be released to be supplemented to the system.
As a preferred embodiment of this embodiment, the air conditioner is operated in a cooling high-load state, and the liquid return prevention device exits the liquid storage mode when any of the following conditions is met:
firstly, the actual superheat degree of an evaporator is less than the target set superheat degree and lasts for 2 min;
secondly, the opening degree of a detection valve of the second throttle valve 11 is less than 440;
thirdly, the liquid discharge mode is continuously operated for 30 min.
Regarding the condition (c), since the liquid discharge mode is started for the high-load operation of the system, after the system operates for 30min, all the refrigerants in the liquid storage tank 3 are released into the system, and the continuous operation is meaningless, at this time, the liquid discharge mode is exited.
As a preferred embodiment of this embodiment, when the air conditioner is in the normal defrosting state, the following three conditions are simultaneously satisfied, the air conditioner liquid return prevention device enters the liquid storage mode, when any one of the conditions is not satisfied, the air conditioner liquid return prevention device exits the liquid storage mode, and the shortest operation time of the liquid storage mode is 30s:
firstly, the superheat degree of an indoor unit is less than 0 ℃;
secondly, the opening degree of the detection valve of the second throttle valve 11 is less than 90;
③ for 30 s.
As a preferred embodiment of this embodiment, when the air conditioner is operated in the normal defrosting state, the following three conditions are simultaneously satisfied, the air conditioner liquid-return prevention device enters the liquid discharge mode, when any one condition is not satisfied, the air conditioner liquid-return prevention device exits the liquid discharge mode, and the shortest operation time of the liquid discharge mode is 30s:
firstly, the superheat degree of an indoor unit is more than 1 ℃;
secondly, the opening degree of a detection valve of the first throttle valve 11 is more than 450;
③ for 30 s.
Claims (8)
1. The utility model provides a liquid device is prevented returning by air conditioner which characterized in that: comprises a four-way reversing valve, a solenoid valve, a liquid storage tank, a first throttle valve and four one-way valves, wherein one end of the solenoid valve is connected with an outlet of the first one-way valve, the other end of the electromagnetic valve is connected with a port g of a four-way reversing valve, a port h of the four-way reversing valve is connected with a port k of the liquid storage tank, the m port of the liquid storage tank is connected with the i port of the four-way reversing valve, the j port of the four-way electromagnetic valve is connected with the first throttle valve, the first throttle valve is connected with the inlets of the third one-way valve and the second one-way valve, the outlet of the fourth one-way valve is connected with the electromagnetic valve, the inlet of the first one-way valve and the outlet of the second one-way valve are connected with one end of a second throttle valve on a refrigerant pipeline between the outdoor heat exchange and the indoor heat exchange of the air conditioner, and the outlet of the third one-way valve and the inlet of the fourth one-way valve are connected to the other end of the second throttling valve on the refrigerant pipeline between the outdoor heat exchange and the indoor heat exchange of the air conditioner.
2. A method for preventing liquid return of an air conditioner is characterized by comprising the following steps: detecting that the air conditioner is in a low-load refrigeration state, enabling the air conditioner liquid return prevention device to enter a liquid storage mode, starting a solenoid valve of the air conditioner liquid return prevention device, and storing redundant refrigerants of the system into a liquid storage tank; detecting that the air conditioner runs in a refrigeration high-load state, enabling the air conditioner liquid return prevention device to enter a liquid drainage mode, starting an electromagnetic valve and a four-way reversing valve of the air conditioner liquid return prevention device, and replenishing a refrigerant in a liquid storage tank into the system; when the condition that the air conditioner meets the defrosting control condition is detected, the air conditioner liquid return prevention device enters a liquid storage mode, a solenoid valve of the air conditioner liquid return prevention device is started, and redundant refrigerants of the system are stored in a liquid storage tank; when the air conditioner is detected to be in the defrosting state, the air conditioner liquid return prevention device is controlled to enter a liquid storage mode or a liquid discharge mode by judging the superheat degree of the indoor unit and the opening degree of a second throttle valve; when the air conditioner is detected to quit defrosting control, the air conditioner liquid return prevention device enters a liquid drainage mode, an electromagnetic valve and a four-way reversing valve of the air conditioner liquid return prevention device are opened, and a refrigerant in the liquid storage tank is replenished into the system.
3. The method for preventing the liquid return of the air conditioner as claimed in claim 2, wherein: the air conditioner in a refrigeration low-load state needs to simultaneously meet the following two opening conditions:
firstly, the actual superheat degree of an evaporator is less than a target set superheat degree and lasts for the first time;
and secondly, detecting that the valve opening degree is smaller than the first valve opening degree by the second throttle valve, and continuing for a second time.
4. The method for preventing the liquid return of the air conditioner as claimed in claim 3, wherein: the air conditioner is in a refrigeration low-load state to operate, and when the following optional conditions are met, the liquid return prevention device exits the liquid storage mode:
firstly, the actual superheat degree of an evaporator is larger than or equal to a target set superheat degree and lasts for a third time;
and the opening degree of the second throttle valve detection valve is larger than the opening degree of the second valve.
5. The method for preventing the liquid return of the air conditioner as claimed in claim 2, wherein: the air conditioner in a refrigeration high-load state needs to simultaneously meet the following two conditions:
firstly, the actual superheat degree of an evaporator is larger than the target set superheat degree and lasts for a fourth time;
and secondly, detecting the valve opening degree of the second throttle valve is larger than the third valve opening degree, and continuing for the fifth time.
6. The method for preventing the liquid return of the air conditioner as claimed in claim 5, wherein: the air conditioner runs in a refrigeration high-load state, and when the following optional conditions are met, the liquid return prevention device exits the liquid storage mode:
firstly, the actual superheat degree of the evaporator is less than the target set superheat degree and lasts for the sixth time;
secondly, detecting the valve opening degree of the second throttle valve to be smaller than the fourth valve opening degree;
and thirdly, continuously operating the liquid discharge mode for the seventh time.
7. The method for preventing the liquid return of the air conditioner as claimed in claim 3, wherein when the air conditioner is operated in a defrosting state, the following three conditions are simultaneously met, the liquid return preventing device of the air conditioner enters a liquid storage mode, and when any one condition is not met, the liquid return preventing device of the air conditioner exits the liquid storage mode:
firstly, the degree of heat exchange in the room is less than a first temperature;
secondly, detecting the valve opening smaller than the first valve opening by a second throttle valve;
and thirdly, lasting for the eighth time.
8. The method for preventing the liquid return of the air conditioner as claimed in claim 5, wherein: when the air conditioner is in defrosting state operation, satisfy following three conditions simultaneously, the liquid device is prevented returning by the air conditioner gets into the flowing back mode, and when arbitrary condition is unsatisfied, withdraw from the flowing back mode:
firstly, the indoor heat exchange superheat degree is higher than a second temperature;
secondly, the opening degree of the first throttle valve is larger than the opening degree of a third valve;
and thirdly, lasting for the ninth time.
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| CN202110140993.2A CN112880228B (en) | 2021-02-02 | 2021-02-02 | Liquid return prevention device and method for air conditioner |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115371308A (en) * | 2022-08-18 | 2022-11-22 | 南京天加环境科技有限公司 | Liquid return prevention air conditioning system and control method |
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| JPH11108473A (en) * | 1997-10-03 | 1999-04-23 | Mitsubishi Heavy Ind Ltd | Air conditioner |
| JP2007285635A (en) * | 2006-04-19 | 2007-11-01 | Hitachi Appliances Inc | Refrigerating cycle device and air conditioner |
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| CN115371308A (en) * | 2022-08-18 | 2022-11-22 | 南京天加环境科技有限公司 | Liquid return prevention air conditioning system and control method |
| CN115371308B (en) * | 2022-08-18 | 2023-12-19 | 南京天加环境科技有限公司 | Liquid return prevention air conditioning system and control method |
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| CN112880228B (en) | 2024-08-13 |
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