JP2002235971A - Method for using existing refrigerant piping - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem in the conventional method for using existing piping that the replacement work takes much expenses in time and effort in replacement of a refrigerating machine oil in a taken-out compressor, enclosing a new refrigerating machine oil, and the following evacuation work, enclosing a new refrigerant. SOLUTION: If an outdoor unit constituting a refrigerating cycle of an old refrigerant can be operated, a cooling operation is performed for a certain period of time by using the outdoor unit. If the outdoor unit can not be operated, old refrigerant recovered from the refrigerating cycle is separated from the refrigerating machine oil by a refrigerant regenerating device. The liquid refrigerant having a low concentration of contained refrigerating oil is circulated in the piping to clean the refrigerating cycle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for replacing an air conditioner which uses a chlorine-containing hydrogen fluoride-based refrigerant as a working fluid with an air conditioner which uses a non-chlorine-based new refrigerant as a working fluid. The present invention relates to a method of using an existing refrigerant pipe of an air conditioner suitable for diverting an existing refrigerant pipe.

[0002]

2. Description of the Related Art As a conventional technique, Japanese Patent Application Laid-Open No. 7-8354 is disclosed.
5 shows a method for changing the refrigerant of the air conditioner described in Japanese Patent Application Publication No. 5 (JP-A-5). Figure 1
0 shows a work flow, and FIG. 11 shows a device configuration. In FIG. 11, the outdoor unit 10 includes a compressor 1, an outdoor heat exchanger 2, an outdoor blower 12, an outdoor expansion device 3, a four-way valve 4, an accumulator 5, a liquid receiver 16, a dryer 15, a gas-side blocking valve 7, The compressor 1, the outdoor blower 3, and the liquid-side check valve 6, the liquid-side check valve 13, and the refrigerant piping connecting them, the pressure and temperature of the refrigeration cycle, and various information from the indoor controllers 24a, 24b, and 24c. And an outdoor control device 8 for controlling the outdoor expansion device 4 and the like, the main components of which are housed in one housing. On the other hand, the indoor heat exchangers 21a, 21b, 21c connected to the plurality of indoor units 20a, 20b, 20c by refrigerant pipes, respectively.
c, indoor expansion devices 23a, 23b, 23c, suction temperature, blowout temperature, remote control switches 25a, 25
b, 25c or the indoor blowers 22a, 22b, 22c and the indoor expansion device 23 based on information from the outdoor control device 8.
a, 23b, and 23c, an indoor control device that controls
24b and 24c, each of which is housed in a housing. These outdoor unit 10 and indoor units 20a, 20
b, 20c are the gas refrigerant pipe 31 and the liquid refrigerant pipe 3
2 are connected. Further, a control signal transmission line 30 is connected between the outdoor control device 8 and the indoor control devices 24a, 24b, 24c.

Next, a method of using the existing piping of the conventional air conditioner thus configured will be described with reference to the work flow of FIG. Here, the components of the air conditioner using the conventional refrigerant are denoted by a suffix q to distinguish them from the components forming the air conditioner using the new refrigerant.

[0004] In the refrigerant recovery operation of the first step S101, first, the liquid-side stop valve 6q of the outdoor unit 10q is closed, and the air conditioner is operated in the test operation mode of cooling. At this time, the operation is continued within a range in which the protection device based on the pressure or the temperature of the refrigeration cycle does not operate, and the gas-side blocking valve 7 is not properly monitored.
After closing q, the test operation mode is released and the air conditioner is stopped. By this operation, most of the HCFC 22, which is the conventional refrigerant in the refrigeration cycle, is recovered by the outdoor unit 10q.

[0005] Next, in a second step S102 (replacement of the outdoor unit), the outdoor unit 10q in which the conventional refrigerant (for example, HCFC22) has been recovered is replaced with a new refrigerant, for example, HFC32 / HF.
Replace with a new outdoor unit 10 corresponding to the C125 / HFC134a mixed refrigerant, and replace the gas refrigerant pipe 31q and the liquid refrigerant pipe 32
q, connect the control signal transmission line 33 to the new outdoor unit. The new outdoor unit 10 conforms to the characteristics of a new refrigeration oil, for example, a polyol ester-based oil, which conforms to the physical properties of the new refrigerant, such as thermodynamic characteristics and transport characteristics.

The next third step S103 (evacuation,
In the case of using refrigerant, the indoor units 20aq, 20bq, 20cq
When the evacuation for exhausting the air in the gas refrigerant pipe 31q and the air in the liquid refrigerant pipe 32q and the conventional refrigerant remaining in the refrigeration cycle is completed, the gas-side stop valve 7 and the liquid-side stop valve 6 are opened, and the new refrigerant is sealed. .

The next fourth step S104 (cleaning operation)
In the above, the air conditioner is operated for a predetermined time in the cooling test operation mode in the same manner as the above, and the new refrigerant and the new refrigerating machine oil are circulated during the refrigeration cycle. By circulating the refrigerant and the refrigerating machine oil, the conventional refrigerating machine oil remaining in the indoor units 20aq, 20bq, 20cq, the gas refrigerant pipe 31q, and the liquid refrigerant pipe 32q is returned to the compressor to reduce the residual concentration.

In a fifth step S105 (replacement of refrigerating machine oil), the refrigerant is recovered from the liquid-side check valve 6 and the like, and the compressor 1 is removed from the new outdoor unit 10 to remove the conventional refrigeration in the compressor 1. Discharge refrigerating machine oil including machine oil.
Then, the unused fresh refrigerating machine oil is sealed in the compressor 1 and returned to the new outdoor unit 10. Further, a new refrigerant is sealed by performing evacuation.

Then, by repeating the fourth step S104 and the fifth step S105, the conventional refrigerant and the conventional refrigeration oil remaining in the refrigeration cycle gradually decrease from the initial residual amounts. This operation is repeated a predetermined number of times so that the residual concentrations of the conventional refrigerant and the conventional refrigerating machine oil become very small to such an extent that the reliability of the equipment using the new refrigerant and the new refrigerating machine oil can be maintained.

Another conventional technique is disclosed in Japanese Unexamined Patent Application Publication No.
In the refrigerating apparatus and the method for using the existing piping in the refrigerating apparatus described in JP-A-325621, when replacing the air conditioner using an HFC-based refrigerant using a mineral oil-based or alkylbenzene-based refrigerating machine oil, the conventional refrigerant HCF is used.
Technology for using refrigerant pipes that have been used for C-based or CFC-based refrigerants without cleaning, and HCFC225,
A technique for reusing after cleaning with an HCFC-based cleaning agent such as 141b is disclosed.

[0011]

Conventionally, when an air conditioner is replaced, particularly when an extension pipe connecting an indoor unit and an outdoor unit is embedded in a wall surface or a ceiling surface of a building, etc. In order to reduce the construction cost (including the cost of parts for the new extension pipe) and the construction time associated with removing and treating the pipe and laying the new extension pipe, it was common to use the existing extension pipe. Conventionally, since the refrigerant and the refrigerating machine oil have been replaced with each other, the existing pipes do not require any particular cleaning or other operations except in special cases such as when the compressor burns out and the refrigerating machine oil deteriorates. Was reused as it was, replacing the indoor unit and the outdoor unit.

However, from the viewpoint of protecting the ozone layer, the use and discharge of a chlorine-containing hydrogen fluoride-based refrigerant (hereinafter referred to as an old refrigerant) is regulated. It can easily be imagined that the replacement with an air conditioner using a refrigerant (hereinafter, referred to as a new refrigerant) as a working fluid will proceed sequentially. At that time, as in the past, we want to use the existing refrigerant pipe to reduce construction costs, but the old refrigerant oil mixed with or remaining in the existing pipe and the old refrigerant dissolved in it, or moisture, when using the existing pipe, Impurities such as air, iron chloride, and copper chloride chemically degrade the refrigerating machine oil compatible with the new refrigerant, and precipitate in the tubes that make up the refrigeration cycle.
There is a problem that the refrigeration cycle is clogged and adhered, and the reliability of the air conditioner is reduced.

Further, since the conventional method of using existing piping according to the conventional technology has the above-described configuration and operation, the method of removing the compressor and replacing the refrigerating machine oil is performed by the new outdoor unit 10 corresponding to the new refrigerant. It is necessary to have a structure in which the compressor 1 can be removed, which is expensive, and it is necessary to repeat several times such as replacing the refrigerating machine oil in the removed compressor, evacuation after enclosing the new refrigerating machine oil, and enclosing the new refrigerant. There is a problem that the work is very troublesome, and accordingly the construction cost is large.

In addition, a method in which a new outdoor unit is a combination of a mineral oil or an alkylbenzene oil and an HFC-based refrigerant is used for a store or business air using a refrigerant pipe connecting long and complicated indoor and outdoor units including branching and the like. For a harmony machine, it is difficult for the refrigerating machine oil that has flowed out during the refrigeration cycle to return to the compressor to ensure lubricity because of these incompatibilities. There has been a problem that an air conditioner must use an ester or ether synthetic oil as a refrigerating machine oil, and the conventional technology cannot be applied to a store or commercial air conditioner.

Further, when replacing the refrigerant with a new refrigerant in a situation where the refrigerating machine oil is extremely deteriorated, such as burning of a compressor, when using an old refrigerant such as an HCFC system, mineral oil or alkylbenzene oil having low compatibility is used. Even if used, the deteriorated old refrigerating machine oil circulates through the refrigerating circuit, causing circuit clogging by sludge and abrasion of the sliding part of the compressor, etc., making it difficult to guarantee the refrigerating cycle performance with a new HFC-based refrigerant. There was a problem that it is.

Further, after washing with an HCFC-based detergent such as HCFC 225, 141b or the like, an existing refrigerant pipe is connected with an air conditioner using an ester-based or ether-based synthetic oil compatible with the HFC-based refrigerant as a refrigerating machine oil. When used, these detergents remain in the piping, causing the chlorine to degrade the refrigerating machine oil and generate sludge in the refrigerating circuit, clogging the refrigerating circuit and lubricating the sliding parts in the compressor. For example, there is a problem that the reliability of the air conditioner is impaired by deteriorating the performance.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is necessary to judge the necessity of pipe cleaning according to the state of an outdoor unit used before reusing an existing pipe, By circulating through the piping as necessary a conventional refrigerant that used the existing piping as a cleaning agent, the residual refrigeration oil concentration in the piping to be used is cleaned to a predetermined value or less, if necessary.
Thereafter, the purpose is to reuse the existing piping for new refrigerant.

[0018]

According to a first aspect of the present invention, there is provided a method of using an existing refrigerant pipe for changing an operating refrigerant of an air conditioner having an indoor unit and an outdoor unit, wherein the operating refrigerant before the change is used. Is circulated for a predetermined time, the remaining concentration of the refrigerating machine oil remaining in the existing refrigerant pipe, which is suitable for the working refrigerant before the change, and the content of the refrigerating machine suitable for the working refrigerant after the change, the content concentration of which is equal to or lower than a predetermined value. After that, the working refrigerant of the air conditioner is changed.

According to a second aspect of the present invention, in the method of using the existing refrigerant pipe according to the first aspect, when the outdoor unit using the working refrigerant before the change is operable, the outdoor unit is set in the cooling or heating mode. Operating for a predetermined time to flow and wash the working refrigerant before the change to the existing refrigerant pipe, pumping down the outdoor unit to collect the working refrigerant before the change to the outdoor unit, and changing to the existing refrigerant pipe Replacing and connecting the outdoor unit and the indoor unit suitable for the working refrigerant of the above.

According to a third aspect of the present invention, in the method of using an existing refrigerant pipe according to the first aspect, when the outdoor unit using the working refrigerant before the change cannot be operated, the outdoor unit uses a refrigerant conveying means. Connecting a refrigerant recovery machine having a refrigerant recovery machine to recover the working refrigerant before the change to a refrigerant recovery cylinder connected to the outlet side of the refrigerant recovery machine, and removing the working refrigerant before the change from the existing refrigerant piping. Removing the used outdoor unit and the indoor unit, connecting a refrigerant recovery device having a refrigerant recovery device and a refrigerant recovery unit connected to the refrigerant recovery cylinder to an existing refrigerant pipe to form a circulation circuit, and transferring the refrigerant to the refrigerant recovery device By operating the means for a predetermined time, the collected working refrigerant collected before the change is flow-washed to the existing refrigerant pipes, and the refrigerant regeneration device separates and removes the refrigerating machine oil dissolved in the working refrigerant before the change. A step of circulating a working refrigerant before the change, in which and a step of connecting interchanged outdoor unit and an indoor unit adapted for working refrigerant after the change to the existing refrigerant piping.

According to a fourth aspect of the present invention, in the method of using the existing refrigerant pipe according to the first aspect, when the outdoor unit using the working refrigerant before the change cannot be operated, the outdoor unit uses the refrigerant conveying means. Connecting a pipe cleaning device having a refrigerant regenerating unit with the refrigerant cleaning unit, and collecting the working refrigerant before the change into a refrigerant recovery cylinder connected to the outlet side of the pipe cleaning device by the refrigerant conveying unit; and Removing the outdoor unit and the indoor unit using the working refrigerant and connecting the pipe cleaning device to the existing refrigerant pipe, and using the refrigerant regenerating means to recover the refrigerating machine oil dissolved in the working refrigerant before the change collected in the refrigerant collection cylinder. Separating and removing, and circulating the working refrigerant before the change regenerated by operating the conveying means for a predetermined time while circulating and washing the existing refrigerant pipe to the existing refrigerant pipe; A step outdoor adapted to working refrigerant after the change to the tube machine and connecting interchanged indoor unit, those having a.

According to a fifth aspect of the present invention, there is provided a refrigerant regenerating means comprising: a closed vessel; a regenerative heat exchanger penetrating downward in the closed vessel; A low-temperature and low-pressure liquid refrigerant that has a pipe and an outflow pipe and that dissolves refrigerating machine oil that flows from the inflow pipe into the closed container is heated and heated by the refrigerant transport means to endothermically evaporate from the refrigerant passing through the regenerative heat exchanger. Then, the evaporated gas refrigerant returns from the outflow pipe to the refrigerant conveying means and circulates, thereby separating and removing the refrigerating machine oil.

According to a sixth aspect of the present invention, the working refrigerant before the change is circulated in an existing refrigerant pipe in a high-pressure liquid state.

According to a seventh aspect of the present invention, the working refrigerant before the change is a hydrogen fluoride-based refrigerant containing chlorine, and the working refrigerant after the change is a hydrogen-hydrocarbon fluoride refrigerant containing no chlorine.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. Figure 1
5 is a procedure flow showing an embodiment of a method of using an existing refrigerant pipe according to the present invention. FIG. 2A is a configuration diagram of an air conditioner before replacement including existing piping to be reused, and FIG. 2B is a configuration diagram of an air conditioner after replacement. In FIG. 2A, 1q is a compressor, 2q is an outdoor heat exchanger, 3q is a decompression device, 4q is a four-way valve, 5q is an accumulator, 6q is a liquid side check valve, 7q is a gas side check valve, These are sequentially connected by a refrigerant pipe as shown in FIG. 2, and constitute an outdoor unit 10q.

Reference numeral 8q denotes an indoor heat exchanger, and the indoor unit 11q
It is installed in. One end of the indoor heat exchanger 8q is connected to the gas-side blocking valve 7 of the outdoor unit 10q via the gas extension pipe 31q.
q, and the other end is connected to a liquid-side blocking valve 6q of the outdoor unit 10q via a liquid extension pipe 32q.

Next, the operation of the air conditioner of the present embodiment configured as described above will be described. In the cooling operation, the refrigerant compressed to a high temperature and a high pressure by the compressor 1q flows into the outdoor heat exchanger 2q through the four-way valve 4q, and radiates heat to outdoor air sent by an outdoor blower (not shown) to condense. Liquefy. This liquid refrigerant becomes a low-temperature, low-pressure gas-liquid two-phase refrigerant in the pressure reducing device 3q, and flows into the indoor heat exchanger 8q through the liquid-side check valve 6q and the liquid extension pipe 32q. Here, heat is absorbed from indoor air sent by an indoor blower (not shown) to evaporate and gasify. This gas refrigerant returns to the compressor 1q via the gas extension pipe 31q, the gas side check valve 7q, the four-way valve 4q, and the accumulator 5q.

On the other hand, in the heating operation, the refrigerant compressed to a high temperature and a high pressure by the compressor 1q is supplied to the four-way valve 4q and the gas-side blocking valve 7q.
Then, the gas flows into the indoor heat exchanger 8q via the gas extension pipe 31q, and radiates heat to indoor air sent by an indoor blower (not shown) to condense and liquefy. This liquid refrigerant passes through the liquid extension pipe 32q and the liquid-side check valve 6q, and is then supplied to the pressure reducing device 3q.
To become a low-temperature, low-pressure gas-liquid two-phase refrigerant at the outdoor heat exchanger 2q
Flows into Here, heat is absorbed from outdoor air sent by an outdoor blower (not shown) to evaporate and gasify. This gas refrigerant returns to the compressor 1q via the four-way valve 4q and the accumulator 5q.

The outdoor unit and the indoor unit constituting the refrigeration cycle (hereinafter referred to as the old refrigerant refrigeration cycle) constructed and operated as described above are provided with a chlorine-containing hydrogen hydrocarbon HCFC22.
Is used as a working fluid, and mineral oil is used as refrigeration oil.
This mineral oil-based refrigerating machine oil is compatible with the HCFC-based refrigerant, and some of the refrigerating machine oil that has flowed out together with the refrigerant from the compressor circulates in the refrigerating cycle during use. Some refrigerating machine oil remains in it, ie in the gas and liquid extension piping.

Next, the refrigeration cycle of the old refrigerant was changed to R407C, which is a chlorine-free HFC-based HFC-based refrigerant.
Is replaced by a refrigeration cycle using a polyol ester oil as a refrigerating machine oil (hereinafter referred to as a refrigeration cycle of a new refrigerant).
The method of using the 32q and 32q as they are will be described based on FIGS. 1 and 2 and with reference to FIG. FIG. 3 is a diagram showing the concentration of mineral oil in the existing pipe due to the change in operation time, in which the vertical axis indicates the amount of the refrigerating machine oil remaining in the (existing) extension pipe and the horizontal axis indicates the cooling operation time.

First, the case where the outdoor unit 10q operates normally in the refrigeration cycle of the old refrigerant will be described. First, in step S11 (forcible cooling operation of the outdoor unit), the outdoor unit 10q is forcibly operated for a certain period of time in the cooling operation test mode. By this operation, the extension piping 3 to be reused
The refrigerating machine oil remaining in 1q and 32q can be controlled to a predetermined level or less. As shown in FIG. 3, when the operation time is short, the amount of residual refrigerating machine oil in the extension pipe is as follows.
While a large amount of refrigerating machine oil remains in the extension piping, the amount of refrigerating machine oil remaining in the extension piping tends to be small if the operation is performed to a certain extent or more. This is because the compressor 1
Since q is not sufficiently warmed, the discharged gas refrigerant and the refrigerating machine oil are not sufficiently separated in the compressor and a large amount of the refrigerating machine oil flows out of the compressor into the refrigerating cycle. When 1q warms up to a certain extent, the refrigerant gas and the refrigerating machine oil are separated in the compressor, so that the refrigerating machine oil does not flow out much to the refrigerating cycle, and the refrigerating machine oil flowing out during the refrigerating cycle dissolves in the liquid of the refrigerant HCFC22. This is because the pressure is returned to the compressor 1q due to the flow rate of the gas of the refrigerant HCFC22.

Incidentally, the allowable value of the residual mineral oil in the existing pipe is at least 5% or less, more preferably 1% or less, based on the mass of the ester oil used as the refrigerating machine oil in the refrigerating cycle of the new refrigerant. . If it is less than or equal to this allowable value, the old refrigerating machine oil remaining in the pipe and the old refrigerant containing chlorine dissolved therein may cause the ester oil to deteriorate in the refrigerating cycle of the new refrigerant or generate sludge. Never. The forced cooling operation time required to keep the concentration of the residual mineral oil below the allowable value may be about 15 minutes. This time is determined by the time required for the compressor to warm up sufficiently and the oil circulation time in the refrigeration cycle.

During the above operation, even if impurities such as iron chloride and copper chloride are present in the existing piping, about 50% of the impurities are H
It can be removed by CFC22 refrigerant. If the outdoor unit can be operated, there is no problem because the amount of these impurities is originally extremely small.

The reason why the cooling operation is performed in step S11 is that the range of air conditions (indoor temperature, outdoor temperature) in which the ordinary air conditioner can operate in the cooling operation is wider. Of course, as long as it is an air condition that can be operated by heating, a test run mode of heating may be used.

The normal operation mode may be used instead of the test operation mode. In this case, it is preferable to set the set temperature to the lowest temperature in the cooling operation and to set the set temperature to the highest temperature in the heating operation so that the operating capacity of the compressor is increased to a certain degree or more. As a result, the operation time is shortened to about 15 minutes.

Next, in step S12 (refrigerant recovery), the air-conditioning apparatus is operated in the cooling test run mode or the pump down mode by closing the liquid side check valve 6q of the outdoor unit 10q (pump down operation: the liquid of the outdoor unit). The side stop valve 6 is closed, the gas side stop valve 7 is opened, the cooling mode is set, and an operation for driving the refrigerant into the outdoor unit is performed. The operation is continued within a range in which the protection device based on the temperature or pressure of the refrigeration cycle does not operate. After a short time, the gas-side blocking valve 7q is closed, the test operation mode is released, and the air conditioner is stopped.
By this operation, the conventional refrigerant HC in the refrigeration cycle
Most of the FC22 refrigerant is recovered in the outdoor unit 10q.
At this time, a pressure gauge is attached to the service port 9q installed in the low-pressure pipe portion such as between the four-way valve 4q and the accumulator 5q, and when the detected pressure is reduced to some extent, for example, -0.3 [kg / cm] ² (G)], the operation can be terminated, and the refrigerant can be more reliably recovered to the outdoor unit without damaging the compressor.

In the next step S13 (replacement of the outdoor unit and the indoor unit), the outdoor unit 10q of the old refrigerant and the indoor unit 1
1q is removed from the gas extension pipe 31q and the liquid extension pipe 32q, and the new refrigerant-compatible outdoor unit 10 and the new refrigerant-compatible indoor unit 11, which constitute a refrigeration cycle of a new refrigerant corresponding to the HFC-based refrigerant and the ester-based refrigerant oil, It is connected to the existing pipes, gas extension pipe 31q and liquid extension pipe 32q.

Then, in step S2 (evacuation),
After connecting the outdoor unit and the indoor unit for the new refrigerant, a vacuum pump is connected to the liquid-side check valve 13 integrated with or near the liquid-side check valve 6 installed in the outdoor unit 10 corresponding to the new refrigerant. And the extension pipes 31q and 32q and the indoor unit 11
Is evacuated. In this process, air and moisture in the existing piping can be removed to a level that does not cause any problem.

Then, the process proceeds to step S3 (opening of the stop valve, charging of refrigerant). After the evacuation is completed, by opening the liquid-side check valve 6 and the gas-side check valve 7, the new refrigerant that has been charged in the outdoor unit corresponding to the new refrigerant in a required amount in advance is charged into the refrigeration cycle. Cycle operation becomes possible. If the extension pipe is long, for example, before opening the liquid-side check valve 6 and the gas-side check valve 7, a predetermined amount of HFC refrigerant is additionally charged from the liquid-side check valve 21 as needed.

As described above, according to the present embodiment, there is no need for special equipment for cleaning existing pipes, and therefore, the construction time and construction cost when replacing with an HFC-based refrigerant or the like that does not contain chlorine. Can be greatly reduced.

Embodiment 2 Next, in the refrigeration cycle having the same configuration as that of the first embodiment, when the outdoor unit 10q cannot be operated due to burnout of the compressor, trouble in the electric system, or the like,
A method of using a new refrigerant refrigeration cycle and using an existing extension pipe will be described.

In the existing gas extension pipe 31q and liquid extension pipe 32q used for the old refrigerant, mineral oil which is a refrigerating machine oil used in the refrigeration cycle of the old refrigerant remains. The residual mineral oil and impurities such as the old refrigerant HCFC22 dissolved in the residual mineral oil degrade the ester oil which is a refrigerating machine oil used in the refrigeration cycle of the new refrigerant HFC, generate sludge, and generate sludge in the refrigeration cycle of the new refrigerant. It is necessary to clean impurities such as mineral oil in the existing piping used by the old refrigerant in order to prevent clogging and make proper operation impossible. In this cleaning, HCFC22 used in the refrigerating cycle of the old refrigerant is used as the cleaning agent.

FIG. 4 is a refrigeration cycle diagram for explaining a method of using an existing pipe, and FIG.
(B) A case where a refrigerant regeneration device and a refrigerant recovery device are connected and used. In the figure, an outdoor unit 10q, an indoor unit 11q,
And the components and gas extension piping 31 that constitute them
Regarding q and the liquid extension pipe 32q, the same or corresponding parts as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.

In the air conditioner of the present embodiment configured as described above, the refrigeration cycle of the old refrigerant is a refrigeration cycle using R407C, which is an HFC-based refrigerant, as the working fluid, and using polyol ester oil as the refrigeration oil. Less than,
A method of using the gas and liquid extension pipes 31q and 32q as they are when replacing with a refrigeration cycle of a new refrigerant) will be described with reference to FIGS.

First, in step S21 (refrigerant recovery), as shown in FIG. 4A, the refrigerant HCFC22 in the refrigeration cycle of the old refrigerant is recovered in a recovery cylinder using a refrigerant recovery machine. In the figure, reference numeral 45 denotes a refrigerant recovery machine, which sequentially connects a second compressor 41, a condensation heat exchanger 42, a second liquid-side check valve 43, and a second gas-side check valve 44 as shown in FIG. It is configured. Further, the liquid-side check valve 13q of the old refrigerant outdoor unit 10q and the second gas-side check valve 44 of the refrigerant recovery unit 45 are connected by the first connection pipe 33, and the refrigerant recovery cylinder 47 and the refrigerant recovery unit 45 are connected. The second liquid-side stop valve 43 is connected to the second connection pipe 34 by the second connection pipe 34. The second gas-side blocking valve 44, the second liquid-side blocking valve 43, and the open / close valve (not shown) of the refrigerant recovery cylinder 47 are opened, and the second
Of the refrigerant in the refrigeration cycle of the old refrigerant
The CFC 22 is collected in a collection cylinder. Then, the second compressor 41 is stopped after closing the second gas-side check valve 44 at an appropriate time. Alternatively, when a low-pressure switch is attached to the low-pressure side of the second compressor 41 in the refrigerant recovery device 45, the compressor is automatically stopped when the refrigerant recovery is terminated by a signal from the low-pressure switch, The second gas-side check valve 44 may be closed immediately after the compressor stops. By this operation, the conventional refrigerant HCF in the refrigeration cycle
Most of C22 is collected in the refrigerant collection cylinder 47.

Next, in step S22 (removal of the outdoor unit and the indoor unit), the outdoor unit 10q of the old refrigerant and the indoor unit 11 are removed.
q is removed from the gas extension pipe 31q and the liquid extension pipe 32q, and the indoor unit side connection portion of the gas extension pipe 31q and the liquid extension pipe 32q is connected by the third connection pipe 35.

The process proceeds to the next step S23 (cleaning operation of existing pipes). Here, as shown in FIG. 4B, the refrigerant regeneration device and the refrigerant recovery device 45 are connected to the existing extension pipes 31q, 3q.
Connect to 2q. In the figure, reference numeral 50 denotes a refrigerant regenerating device, which comprises an oil recovery container 51, a regenerative heat exchanger 52, an oil recovery port 53, a refrigerant inflow pipe 54, a refrigerant outflow pipe 55, and a regeneration decompression device 56. The regenerative heat exchanger 52 includes an oil recovery container 51.
, And the regenerative decompression device 56 is installed in the middle of the refrigerant inflow pipe 54.

Then, one end of the regenerative heat exchanger 52 is connected to the refrigerant recovery cylinder 47 via the fourth connection pipe 36, and the other end is connected to the second liquid-side stop valve 43 of the refrigerant recovery machine 45.
In addition, a refrigerant liquid outflow pipe 37 extending from the lower portion inside the refrigerant recovery cylinder 47 to the outside is connected to one end of the liquid extension pipe 32q on the outdoor unit side. Here, a third liquid-side stop valve 46 is provided in the refrigerant liquid outflow pipe 37. Further, the refrigerant inflow pipe 54 of the refrigerant regeneration device 50 is connected to one end of the gas extension pipe 31q on the outdoor unit side via the fifth connection pipe 38. Furthermore, the refrigerant outlet pipe 55 of the refrigerant regeneration device 50 is connected to the second gas-side blocking valve 44 of the refrigerant recovery unit 45.

Next, the operation of the refrigeration cycle configured as described above will be described. The refrigerant HCFC 22, which has become high temperature and high pressure in the second compressor 41, is condensed by the condensing heat exchanger 42.
Then, heat is radiated to outdoor air sent by a blower (not shown) and partially condensed and liquefied. The gas-liquid two-phase refrigerant passes through the second liquid-side check valve 43 and passes through the regenerative heat exchanger 52.
Flows into Here, heat is radiated to the low-temperature and low-pressure refrigerant inside the oil recovery container 51 to be further condensed and liquefied. This liquid refrigerant flows into the refrigerant recovery cylinder 47 via the fourth connection pipe 36.
The liquid refrigerant flowing out from the lower part inside the refrigerant recovery cylinder 47 passes through the refrigerant liquid outflow pipe 37 and flows into the existing liquid extension pipe 32q. Here, the mineral oil, which is the refrigerating machine oil remaining by the operation of the refrigeration cycle of the old refrigerant, is dissolved.
The liquid refrigerant in which the residual mineral oil in the liquid extension pipe 32q is dissolved flows into the other existing pipe, the gas extension pipe 31q, via the third connection pipe 35. Here, the mineral oil, which is the refrigerating machine oil remaining by the operation of the refrigeration cycle of the old refrigerant, is further dissolved, and the refrigerant is recycled through the fifth connection pipe 38 to the refrigerant regeneration device 50.
Flows into the refrigerant inflow pipe 54. This liquid refrigerant is throttled by the regeneration decompression device 56 to become a low-temperature low-pressure gas-liquid two-phase refrigerant, and flows into the oil recovery container 51. Here, the gas-liquid two-phase refrigerant in which the residual mineral oil is dissolved is heated by the regenerative heat exchanger 52,
Only the refrigerant HCFC22 evaporates and gasifies. The gas refrigerant returns to the refrigerant recovery device 45 through the refrigerant outflow pipe 55, is drawn into the second compressor 41 via the second gas-side blocking valve 44, and circulates. In such a cleaning operation of the existing pipe by the refrigerant, the residual mineral oil in the existing pipe can be reduced to an allowable value or less by continuing the operation at least until the refrigerant makes one cycle.

In the oil recovery container 51, only the HCFC 22, in which the mineral oil remaining in the existing piping is dissolved, absorbs heat from the regenerative heat exchanger 52 and evaporates, and the mineral oil stays in the lower part of the container. Thus, the refrigerant and the mineral oil are separated, and the extracted mineral oil is discharged from the oil recovery port 53 later. Also,
Regenerated refrigerant HCFC22 has extremely low mineral oil concentration,
Mineral oil remaining in the existing piping can be dissolved and removed more.

The HCFC 22 can also remove about 50% of iron chloride and copper chloride. Therefore, even if these impurities are present in the existing refrigerant pipe, the amount of each of these impurities is different from that of the refrigerating machine oil suitable for the new refrigerant. If the value is equal to or less than twice the allowable value, the washing can be performed to the allowable value or less, so that the reliability of the refrigeration cycle of the new refrigerant can be ensured.

The regeneration pressure reducing device 56 is connected to the refrigerant outlet pipe 5
5 is a certain value, for example, 5 [de]
g] or more. If a temperature-type expansion valve, an electronic expansion valve (LEV), or the like is used as the regeneration decompression device 56, the degree of superheat can be automatically adjusted.

Further, the regenerative heat exchanger 52 converts the two-phase refrigerant obtained by squeezing the saturated liquid refrigerant having a temperature slightly higher than the assumed outside air temperature to a predetermined pressure by an equal enthalpy change into a superheated gas state at the predetermined pressure. It is desirable that the heating capacity be sufficient (heat transfer area, heat transmission rate). However, if the heating capacity is insufficient, a heating device such as a heater may be added around or inside the oil recovery container 51.

Next, in step S24 (refrigerant recovery), the refrigerant HCF
C22 is collected in a collection cylinder. Third liquid-side check valve 46
Are closed, and the second gas-side check valve 44 and the second liquid-side check valve 4
3, the on-off valve (not shown) of the refrigerant recovery cylinder 47 is opened, and the second compressor 41 is operated to recover the HCFC 22 used for pipe cleaning in the recovery cylinder.

Then, the process proceeds to step S25 (installation of an outdoor unit and an indoor unit corresponding to a new refrigerant), where the third connection pipe 35, the fifth connection pipe 38, and the refrigerant liquid outflow pipe 37 are connected to the existing gas extension pipe. Remove from 31q and liquid extension pipe 32q. Thereafter, the outdoor unit 10 corresponding to the new refrigerant and the indoor unit 8 corresponding to the new refrigerant constituting the refrigeration cycle of the new refrigerant corresponding to the HFC-based refrigerant and the ester-based refrigerating machine oil are connected to the existing pipe, ie, the gas extension pipe 31q and the liquid extension. Piping 32
Connect to q.

Thereafter, in step S2 (vacuum evacuation), after the connection, the liquid-side check valve 21 installed integrally with or near the liquid-side check valve 6 installed in the outdoor unit 10 corresponding to the new refrigerant. A vacuum pump is connected, and the extension pipes 31q, 32q and the indoor unit 11 are evacuated.
In this process, air and moisture in the existing piping can be removed to a level that does not cause any problem.

Finally, in step S3 (opening of the stop valve, charging of the refrigerant), after the evacuation is completed, the liquid-side stop valve 6 and the gas-side stop valve 7 are opened, so that the new refrigerant-compatible outdoor unit has a required amount in advance. Since the charged new refrigerant is charged into the refrigeration circuit, the refrigeration cycle of the new refrigerant can be operated. If the extension pipe is long, for example, before opening the liquid-side check valve 6 and the gas-side check valve 7, a predetermined amount of HFC refrigerant is additionally charged from the liquid-side check valve 21 as needed.

Refrigerant recovery cylinder 4 used in the present embodiment
7 requires a volume equal to or greater than the sum of the volume of the gas pipe and the volume of the old refrigerant filled in the refrigeration cycle of the old refrigerant in the extension pipe to be cleaned and reused. This is because the liquid of the old refrigerant circulates through the gas pipe of the extension pipe, and therefore, at the time of pipe cleaning, at least the volume of the old refrigerant that is equal to or greater than the volume of the extension pipe to be cleaned is necessary. Old refrigerant HCFC22 and new HCFC collected at another site
It is desirable to additionally charge 22 or to charge the refrigerant recovery cylinder 47 in advance.

If the amount of the refrigerant is insufficient at the time of cleaning, the old refrigerant HCFC22 circulates in a two-phase state in the existing refrigerant pipe to be cleaned. In this case, the refrigerant liquid is annularly circulated in the pipe to be cleaned. The refrigerant gas flows in the central part in a so-called annular flow, the refrigerant gas flows as large bubbles in the refrigerant liquid, or a so-called plug flow, or the refrigerant gas flows in the refrigerant liquid as small bubbles. A so-called bubble flow is convenient because the refrigerant liquid comes into contact with the inner surface of the pipe and the refrigerating machine oil attached to the inner surface of the pipe can be dissolved and removed. When the refrigerant amount is insufficient, the capacity of the second compressor 41, the opening degree of the regenerative pressure reducing device 56, the heat exchange amount of the regenerative heat exchanger 52, The amount of heat exchange of the condensation heat exchanger 42 is adjusted.

As the second compressor 41 used in the refrigerant recovery unit 45 used in the present embodiment, it is desirable to use an oil-free compressor that does not require lubricating oil in the sliding part.
Even if the residual mineral oil in the existing extension pipe flows into the refrigerant recovery device 45 when the oil recovery container 51 overflows with the recovered oil, the oil-free compressor does not cause a problem such as failure. .

The second compressor 4 in the refrigerant recovery unit 45
If there is no suitable oil-free compressor, a compressor of a reciprocating type, a rotary type, a scroll type, or the like used in an ordinary air conditioner may be used. In this case, a high-performance oil separator having an oil separation efficiency of preferably 90% or more is installed on the discharge side of the compressor. Examples of the high-performance oil separator include a mesh type shown in JP-A-11-173707 and a centrifugal type shown in JP-A-58-168864.

Embodiment 3 In the above-described second embodiment, the refrigerant regenerating apparatus and the refrigerant recovery machine are shown as being separated from each other, but the refrigerant recovery function as shown in FIGS.
An apparatus having a refrigerant regeneration function and a pipe cleaning function (hereinafter, a pipe cleaning apparatus) may be used. Hereinafter, in the third embodiment,
A method for cleaning gas and liquid extension pipes using this pipe cleaning apparatus and making the pipes usable in a new refrigerant unit will be described.
5 is a refrigerant circuit diagram during the refrigerant recovery operation, FIG. 6 is a refrigerant circuit diagram during the refrigerant regeneration operation, and FIG. 7 is a refrigerant circuit diagram during the extension pipe washing. The same or corresponding parts as those in FIG. 4 are denoted by the same reference numerals, and description thereof will be omitted. FIG. 8 shows a procedure flow of a method of using an existing refrigerant pipe in the third embodiment.

First, step S31 in FIG. 8 (refrigerant recovery)
5, the liquid side check valve 21q (not shown) of the old refrigerant outdoor unit 10q and the pipe cleaning device 5 as shown in FIG.
7 is connected by the connection pipe 33 to the refrigerant recovery cylinder 47 and the outlet-side prevention valve 6 of the pipe cleaning device 57.
1 are connected by a connection pipe 34. At this time, the flow path switching valve 62 mounted on the pipe cleaning device 57 is switched in the direction indicated by the solid line in FIG. Inlet blocking valve 5
8. The outlet-side blocking valve 61 and the open / close valve on the inflow side of the refrigerant recovery cylinder 47 are opened, and the compressor 41 of the pipe cleaning device is operated to recover the HCFC 22 in the refrigeration cycle of the old refrigerant into the refrigerant recovery cylinder 47.

After closing the inlet-side stop valve 58 at an appropriate time, the compressor 41 is stopped. Alternatively, if the low pressure switch 68 is mounted on the low pressure side of the pipe washer, the compressor is automatically stopped when the refrigerant recovery is completed by the operation signal based on the detected pressure. What is necessary is just to close 58. In addition, by installing the check valve 64, when the compressor is stopped, the outdoor unit of the old refrigerant has HCF.
C22 can be prevented from flowing backward. Further, when the HCFC 22 to be recovered gasifies as the refrigerant recovery proceeds,
By opening the bypass valve 65 of the pressure reducing device 63, the refrigerant gas recovery speed can be increased. By the above operation, HCFC which is the conventional refrigerant in the refrigeration cycle in the outdoor unit 10q
Most of 22 is collected in the refrigerant collection cylinder.

Next, in step S32 (removal of the outdoor unit and the indoor unit), the outdoor unit 10q and the indoor unit 1
1q is removed from the gas extension pipe 31q and the liquid extension pipe 32q, and the connection unit 35 of the gas extension pipe and the liquid extension pipe is connected to the indoor unit side. Further, the connection part of the gas extension pipe 31q on the outdoor unit side is connected to the pipe connection port 60 of the pipe cleaning device.
Then, the outdoor unit side connection part of the liquid extension pipe 32q is connected to the pipe connection port 59 of the pipe cleaning device, respectively. After connecting the existing pipe, vacuum evacuation is performed in advance using a check valve at the gas or liquid extension pipe connection of the pipe cleaning device.

In the next step S33 (regeneration operation of the recovered refrigerant), when the HCFC 22 is recovered from the outdoor unit of the old refrigerant, a part of the refrigerating machine oil recovered from the old refrigerant compressor is also recovered and recovered there. The HCFC 22 is purified (regenerated) to a level usable for cleaning the piping. FIG.
Will be described based on the refrigerant circuit diagram of the refrigerant regeneration operation. First, the inlet blocking valve 58 of the pipe cleaning device 57 and the refrigerant recovery cylinder 47
The outlet and the connection pipe 33 are connected. On the other hand, the pipe cleaning device 5
The outlet-side stop valve 61 of FIG. 7 and the inlet of the refrigerant recovery cylinder 47 are connected by the connection pipe 34 during the refrigerant recovery operation, so there is no particular need to reconnect.

The operation of the cycle during the refrigerant regeneration operation in this configuration will be described with reference to FIG. The HCFC 22 refrigerant is circulated through the refrigeration cycle by operating the compressor 41 while maintaining the flow path switching valve 62 of the pipe cleaning device 57 in the direction indicated by the solid line in FIG.
At this time, the liquid HCFC22 refrigerant sucked up from the refrigerant recovery cylinder 47 and flowing into the pipe cleaning device 57 has solid foreign substances contained in the refrigerant removed by the strainer 66, passes through the pressure reducing device 63, and the pressure is reduced, and the gas-liquid two-phase It enters the state and flows into the oil recovery container 51. Here, the gas-liquid two-phase HCHC22 refrigerant in which the refrigerator oil is dissolved exchanges heat with the high-temperature and high-pressure HCHC22 passing through the regenerative heat exchanger 52, is superheated, and only the HCFC22 evaporates and gasifies. In this process, the refrigerating machine oil contained in the HCFC 22 is separated and collected and purified. This gasified HCFC22
Is sucked into the compressor 41, discharged as a high-temperature and high-pressure gas by the compression process, and flows into the condensation heat exchanger 42. Here, heat is radiated to the outdoor air and partially condensed to be in a gas-liquid two-phase state.
The HCFC 22 in the high-pressure two-phase state flows into the regenerative heat exchanger 52, radiates heat to the low-temperature and low-pressure refrigerant outside the regenerative heat exchanger stored inside the oil recovery container 51, and is further condensed and liquefied. This liquid refrigerant flows into the refrigerant recovery cylinder 47 and circulates.

By circulating the HCFC22 refrigerant in the pipe cleaning device 57 in this manner, the mineral oil dissolved in the refrigerant is separated and collected in the oil recovery container 51 to purify the refrigerant. Then, the purified HCFC 22 is used as a pipe cleaning agent. After performing the refrigerant regeneration operation for a certain period of time, the operation is stopped, and the process proceeds to the next step, which is the pipe cleaning operation. The operation may be shifted to the pipe cleaning operation without stopping the operation after the regeneration operation.

In the next step S34 (pipe cleaning operation), the flow path switching valve 62 is switched to the cleaning operation side (solid line in the figure) as shown in the refrigerant circuit diagram at the time of pipe cleaning in FIG. Open the on-off valves of the pipe connection ports 59 and 60,
The operation of the pipe cleaning device 57 is started. When the compressor 41 of the pipe cleaning device is operated, H purified by the refrigerant regeneration operation is removed.
The CFC 22 flows out of the refrigerant recovery cylinder 47 in a liquid state,
Once flowing into the pipe cleaning device from the pipe cleaning device inlet 58, it passes through the flow path switching valve 62 and is connected to the pipe connection port 59.
The gas flows into the gas extension pipe 31q, which is a pipe to be cleaned,
Gas extension pipe 31 on the indoor unit side attached in step S32
The liquid flows into the pipe cleaning device 57 again from the pipe connection port 60 via the connection pipe 35 connecting the q and the liquid extension pipe 32q. The regenerated HCFC used in step S34
The 22 refrigerant has a very low concentration of mineral oil, and can dissolve and remove a large amount of mineral oil remaining in the piping.

The refrigerant (including the mineral oil in the pipes) returned from the gas and liquid extension pipes 31q and 32q to the pipe cleaning device 57 is thereafter subjected to the strainer 66 by the strainer 66 in the same manner as the cycle during the regeneration operation described in step S33. The solid foreign matter is removed, passes through the pressure reducing device 63, separates and removes oil in the oil recovery container 51, and returns to the refrigerant recovery cylinder 47 via the compressor 41, the condensation heat exchanger 42, and the regenerative heat exchanger 52.

Such a pipe cleaning operation is continued at least until the refrigerant makes a round in the pipe to be cleaned, and the amount of residual mineral oil in the existing pipe is reduced to an allowable value or less. After the cleaning of the pipe is completed, the on-off valve at the outlet of the refrigerant recovery cylinder 47 is closed,
The HCFC 22 used for washing is collected. At the time of refrigerant recovery, in the same manner as when recovering from the old refrigerant outdoor unit, at an appropriate time, the inlet-side blocking valve 58 or the on-off valve at the outlet of the refrigerant recovery cylinder 47 is closed to stop the refrigerant from flowing out of the cylinder and to stop the H in the pipe.
Start collection of CFC22 refrigerant, drive refrigerant into cylinder and wait for the time when vacuum is released.
Close the on-off valves 9, 60 and stop the operation.

Next, at step S35 (the outdoor unit corresponding to the new refrigerant,
In the installation of the indoor unit), after cleaning the pipes, the cleaned gas and liquid extension pipes 31q, 32q are removed from the pipe connection ports 59, 60 of the pipe cleaning device 57. Thereafter, the new refrigerant compatible outdoor unit 10 and indoor unit 11 are connected to the cleaned gas and liquid extension pipes 31q, 32q. After the connection, the above-mentioned extension pipe and the indoor unit are evacuated, and after completion, the outdoor unit liquid-side check valve 6 and the gas-side check valve 7 are opened, and the new refrigerant is charged into the refrigerant circuit, so that the unit corresponding to the new refrigerant can be operated. State.

Refrigerant recovery cylinder 4 used in this embodiment
7 requires a volume equal to or greater than the total volume of the gas extension pipe 31q and the volume of the old refrigerant filled in the refrigeration cycle of the old refrigerant among the extension pipes to be cleaned and reused. This is because the liquid of the old refrigerant circulates in the gas extension pipe 31q as in the second embodiment. Therefore, at the time of pipe cleaning, at least the amount of old refrigerant that is equal to or larger than the volume of the extension pipe to be cleaned is required.

If the amount of the refrigerant is insufficient during the cleaning, the old refrigerant circulates in the existing refrigerant pipe to be cleaned in a gas-liquid two-phase state. In this case, the refrigerant liquid flows through the extension pipe to be cleaned. Either a so-called annular flow in which the refrigerant gas flows in the center and flows in the center portion, a so-called plug flow in which the refrigerant gas flows as large bubbles in the refrigerant liquid, or small bubbles in the refrigerant liquid The so-called bubble flow is convenient because the refrigerant liquid comes into contact with the inner surface of the pipe and the refrigerating machine oil attached to the inner surface of the pipe can be dissolved and removed.
Therefore, when the refrigerant amount is insufficient, the capacity of the compressor 41, the opening degree of the regenerative decompression device 56, the heat exchange amount of the regenerative heat exchanger 52,
The amount of heat exchange of the condensation heat exchanger 42 is adjusted.

It is desirable to use an oil-free compressor which does not require a lubricating oil for the sliding part as the compressor 41 used in the pipe washing machine 57 used in the present embodiment.
If there is no suitable oil-free compressor in the pipe washer, a reciprocating compressor, a rotary compressor, a scroll compressor, or the like used in an ordinary air conditioner may be used. In this case, the oil separation efficiency is desirably 90% on the discharge side of the compressor.
A high performance oil separator as described above will be installed.

In the first to third embodiments, HCFC2 is used as the refrigerant used in the refrigeration cycle of the old refrigerant.
2. The case where mineral oil is used as the refrigerating machine oil, R407C is used as the refrigerant used in the refrigerating cycle of the new refrigerant, and polyol ester is used as the refrigerating machine oil has been described as an example, but other HCFC-based refrigerants (R22, R502, etc.) or CF
Pipes used in a refrigerating cycle using a refrigerating machine oil such as a mineral oil compatible with a C-based refrigerant (such as R12) and alkylbenzene are replaced with chlorine-free R407C, R410A, and R13.
Similar effects can be obtained in all cases where the refrigerant is used in a refrigeration cycle using a refrigerating machine oil (polyol ester, polyvinyl ether, fluorine-based oil, etc.) compatible with HFC-based refrigerants such as 4a, R32, R404A, and R507A.

Embodiment 4 In the refrigeration cycle of the new refrigerant, when mineral oil or alkylbenzene oil having low compatibility with the HFC-based refrigerant is used as the refrigerating machine oil, an example in which the existing piping is not washed is disclosed in JP-A-11-325621. In the case where the compressor is burned due to an excessive load applied to the compressor in the refrigeration cycle of the old refrigerant, for example, the continuation of the liquid back operation or the like, the existing piping is connected to the HCFC 22 as in the second embodiment. Wash with. The refrigerating machine oil remaining in the existing piping when the compressor burns out in the refrigerating cycle of the old refrigerant is significantly deteriorated, and
Since the residual amount is expected to be large, no sludge is generated at all even if a new refrigerant having a low compatibility with the new HFC-based refrigerant, such as mineral oil or alkylbenzene oil, is used as the refrigerating machine oil in the refrigeration cycle. This is because it cannot be said. Therefore, similarly to Embodiment 2, HC
By cleaning the piping with FC22, the reliability of the refrigeration cycle of the new refrigerant can be improved.

Further, the piping used for the HFC-based refrigerant, which is a chlorine-free hydrogen fluoride-based refrigerant, is replaced with a refrigeration cycle using the HFC-based refrigerant, which is also a chlorine-free refrigerant containing hydrogen fluoride. Even when using, Embodiment 1
The operation is performed according to the third embodiment. Further, even if the old refrigerant and the old refrigerating machine oil are R410A and an alkylbenzene oil, and the new refrigerant and the new refrigerating machine oil are new incompatible oils, the old refrigerant having a high pressure and a high temperature is circulated through the existing piping according to the method of the present invention. Since the solubility of the alkylbenzene oil in R410A is slightly increased, the same effects as described in the first and second embodiments can be obtained.

Further, the present invention is not limited to a hydrocarbon-based fluorocarbon refrigerant as the working fluid, and the old refrigerant and the new refrigerant may be hydrocarbon-based refrigerants, carbon dioxide, ammonia, water,
The present invention can be applied to any refrigerant, including air and the like, in which the old refrigerant and the old refrigerating machine oil remaining in the existing piping may adversely affect the refrigeration cycle of the new refrigerant.

That is, as shown in FIG. 8, by working according to the procedure of the existing pipe utilization method described in the present invention, the influence of the old refrigerating machine oil remaining in the existing pipe and the old refrigerant dissolved therein is minimized. Therefore, the reliability of the refrigeration cycle of the new refrigerant using the existing piping can be improved.

[0081]

The method for utilizing an existing pipe according to the present invention has the following effects.

According to the first aspect of the present invention, in the method of using the existing refrigerant pipe when changing the working refrigerant of the air conditioner including the indoor unit and the outdoor unit, the working refrigerant before the change is circulated for a predetermined time. Then, the concentration of the refrigerating machine oil remaining in the existing refrigerant pipe, which is suitable for the working refrigerant before the change, is set to a concentration below a predetermined value with respect to the usage amount of the refrigerator suitable for the working refrigerant after the change, and then the air Since the working refrigerant of the air conditioner is changed, the existing refrigerant piping can be reused in the refrigeration cycle of the new refrigerant without cleaning, reducing the construction time and construction costs associated with replacing with refrigerant that does not contain chlorine. A highly reliable HFC-based refrigerant refrigeration cycle can be provided.

According to the second aspect of the present invention,
When the outdoor unit using the working refrigerant before the change is operable, the outdoor unit is operated in the cooling or heating mode for a predetermined time to flow and wash the working refrigerant before the change to the existing refrigerant pipe, and the outdoor unit is pumped. A step of recovering the working refrigerant before the change by the down operation to the outdoor unit, and a step of replacing and connecting the outdoor unit and the indoor unit suitable for the working refrigerant after the change to the existing refrigerant piping, so that the existing refrigerant piping is provided. This does not require special equipment for cleaning, and can greatly reduce the construction time and construction costs associated with replacement with HFC-based refrigerants containing no chlorine.

According to the third aspect of the present invention,
If the outdoor unit using the working refrigerant before the change cannot be operated, connect the outdoor unit to a refrigerant recovery device having a refrigerant transport unit, and the refrigerant recovery device outputs the working refrigerant before the change to the outlet of the refrigerant recovery device. And a refrigerant recovery means connected to the refrigerant recovery cylinder connected to the refrigerant recovery cylinder and removing the outdoor unit and the indoor unit using the working refrigerant before the change from the existing refrigerant pipe. Connecting the regenerating device to the existing refrigerant pipe to form a circulation circuit, and operating the refrigerant conveying means of the refrigerant recovery machine for a predetermined time to flow and clean the collected working refrigerant to the existing refrigerant pipe and regenerate the refrigerant. A step of separating and removing the refrigerating machine oil dissolved in the working refrigerant before the change by the device and circulating the working refrigerant before the change, and an outdoor suitable for the working refrigerant after the change to the existing refrigerant piping. And the step of switching and connecting the indoor unit, and the collected old refrigerant is separated from the oil by the refrigerant regenerating device, and the refrigerant liquid having a reduced concentration of the refrigerating machine oil is circulated in the piping, so that Dissolves and removes the refrigerating machine oil remaining in the furnace, reducing the construction time and construction costs associated with replacing with refrigerants that do not contain chlorine, and providing a reliable refrigeration cycle for HFC-based refrigerants. Becomes

According to the fourth aspect of the present invention,
If the outdoor unit using the working refrigerant before the change is not operable, connect a pipe cleaning device having a refrigerant transfer unit and a refrigerant regeneration unit to the outdoor unit, and pipe the working refrigerant before the change by the refrigerant transfer unit. Collecting the refrigerant in the refrigerant recovery cylinder connected to the outlet side of the cleaning device, removing the outdoor unit and the indoor unit using the working refrigerant before the change from the existing refrigerant piping, and connecting the piping cleaning device to the existing refrigerant piping; ,
A step of separating and removing the refrigerating machine oil dissolved in the working refrigerant before the change collected in the refrigerant recovery cylinder by the refrigerant regenerating means, and a step of operating the transport means for a predetermined time to transfer the working refrigerant before the change regenerated by the existing refrigerant pipe Circulating while washing and circulating to the existing refrigerant pipe, and replacing and connecting the outdoor unit and indoor unit that are compatible with the working refrigerant after the change to the existing refrigerant pipe. It is possible to provide a highly reliable HFC-based refrigerant refrigeration cycle while reducing time and construction costs.

According to the fifth aspect of the present invention,
The refrigerant regenerating means includes a closed vessel, a regenerative heat exchanger that penetrates downward in the closed vessel, and an inflow pipe and an outflow pipe that are disposed through the upper part of the closed vessel and open at one end. The low-temperature and low-pressure liquid refrigerant that dissolves the refrigerating machine oil that flows into the closed container becomes high-temperature and high-pressure by the refrigerant conveying means, and is endothermic and evaporates from the refrigerant that passes through the regenerative heat exchanger. Since the refrigerating machine oil is separated and removed by circulating back to the transporting means, it is possible to reduce the construction time and construction cost associated with the replacement with a refrigerant containing no chlorine and to provide a highly reliable refrigeration cycle of HFC-based refrigerant. It becomes possible.

According to the sixth aspect of the present invention,
Since the working refrigerant before the change is circulated in the existing refrigerant pipe in a high-pressure liquid state, the state of the refrigerant flow becomes an annular flow or a plug flow, and the liquid refrigerant flows in contact with the inner surface of the piping, and the refrigerating machine oil adheres to the inner surface of the piping. Can be efficiently dissolved and removed, and the construction time can be shortened.

According to the seventh aspect of the present invention,
Since the working refrigerant before the change is a hydrogen fluoride-based refrigerant containing chlorine, and the working refrigerant after the change is a hydrogen-carbon fluoride-based refrigerant containing no chlorine, a highly reliable HFC-based refrigerant refrigeration cycle is provided. It is possible to do.

[Brief description of the drawings]

FIG. 1 is a procedure flow of a method for using an existing pipe according to Embodiments 1 and 2 of the present invention.

FIG. 2 is a configuration diagram of the air conditioner according to Embodiment 1 of the present invention before (a) replacement and after (b) replacement.

FIG. 3 is a diagram illustrating a mineral oil concentration in an existing pipe according to Embodiment 1 of the present invention.

FIG. 4 is a refrigeration cycle diagram of (a) a case where a refrigerant recovery device is used and (b) a case where a refrigerant regeneration device and a refrigerant recovery device are used in a method of utilizing an existing pipe according to Embodiment 2 of the present invention.

FIG. 5 is a refrigerant circuit diagram during a refrigerant recovery operation according to Embodiment 3 of the present invention.

FIG. 6 is a refrigerant circuit diagram during a refrigerant regeneration operation according to Embodiment 3 of the present invention.

FIG. 7 is a refrigerant circuit diagram at the time of cleaning an extension pipe according to Embodiment 3 of the present invention.

FIG. 8 is a procedure flow of a method of using an existing refrigerant pipe according to Embodiment 3 of the present invention.

FIG. 9 is a diagram illustrating an application classification according to a fourth embodiment of the present invention.

FIG. 10 is a work flow of a conventional method of using existing piping.

FIG. 11 is a diagram showing a device configuration of a conventional method of using existing piping.

[Explanation of symbols]

1,1q compressor, 2,2q outdoor heat exchanger, 3,3q
Pressure reducing device, 4,4q four-way valve, 5,5q accumulator, 6,6q liquid side check valve, 7,7q gas side check valve,
8q indoor heat exchanger, 9q service port, 10,1
0q outdoor unit, 11, 11q indoor unit, 12 outdoor blower, 13 liquid side check valve, 14 outdoor control device, 1
5 dryer, 16 liquid receiver, 20 indoor unit, 21 indoor heat exchanger, 22 indoor blower, 23 indoor expansion device,
24 indoor control device, 25 remote control switch, 30 control signal transmission line, 31, 31q gas extension pipe, 32, 3
2q liquid extension pipe, 33 first connection pipe, 34 second connection pipe, 35 third connection pipe, 36 fourth connection pipe, 3
7 refrigerant liquid outflow pipe, 38 fifth connection pipe, 41 second compressor, 42 condensation heat exchanger, 43 second liquid-side check valve, 44 second gas-side check valve, 45 refrigerant recovery machine, 4
6 third liquid side check valve, 47 refrigerant recovery cylinder, 50
Refrigerant recycling device, 51 oil recovery container, 52 regenerative heat exchanger, 53 oil recovery port, 54 refrigerant inflow pipe, 55 refrigerant outflow pipe, 56 regeneration decompression device, 57 pipe washing device, 58
Inlet blocking valve, 59, 60 piping connection port, 61 outlet blocking valve, 62 flow switching valve, 63 pressure reducing device, 64
Check valve, 65 bypass valve, 66 strainer.

Continuing from the front page (72) Inventor Masato Shijunomiya 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Sanrishi Electric Co., Ltd. (72) Inventor Norihide Kazemura 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Electric Co., Ltd.

Claims (7)

[Claims] 1. A method of using an existing refrigerant pipe when changing an operating refrigerant of an air conditioner including an indoor unit and an outdoor unit, wherein the operating refrigerant before the change is circulated for a predetermined time, and the refrigerant flows through the existing refrigerant pipe. The working refrigerant of the air conditioner is changed after the remaining amount of the refrigerating machine oil that is compatible with the working refrigerant before the change is set to a concentration equal to or less than a predetermined value with respect to the usage amount of the refrigerator that is compatible with the changed working refrigerant. A method for utilizing an existing refrigerant pipe. 2. When the outdoor unit using the working refrigerant before the change is operable, the outdoor unit is operated in a cooling or heating mode for a predetermined time to flow and wash the working refrigerant before the change to the existing refrigerant pipe. Performing the step of pumping down the outdoor unit to recover the working refrigerant before the change to the outdoor unit, and switching and connecting the outdoor unit and the indoor unit suitable for the working refrigerant after the change to the existing refrigerant pipe. The method according to claim 1, further comprising the step of: 3. When the outdoor unit using the working refrigerant before the change is not operable, a refrigerant recovery device having a refrigerant transfer means is connected to the outdoor unit, and the refrigerant recovery device is connected to the outdoor unit by the refrigerant recovery device. Recovering the working refrigerant in a refrigerant recovery cylinder connected to the outlet side of the refrigerant recovery machine, and removing the outdoor unit and the indoor unit using the working refrigerant before the change from the existing refrigerant pipe and removing the refrigerant recovery machine; Forming a circulation circuit by connecting a refrigerant regenerating device having refrigerant regenerating means connected to the refrigerant collecting cylinder to the existing refrigerant pipe, and recovering the refrigerant by operating the refrigerant conveying means of the refrigerant collecting machine for a predetermined time; The working refrigerant before the change is flow-washed to the existing refrigerant pipes, and the refrigerant regenerating device separates and removes the refrigerating machine oil dissolved in the working refrigerant before the change to perform the operation before the change. The method according to claim 1, further comprising the steps of: circulating a refrigerant; and exchanging and connecting an outdoor unit and an indoor unit adapted to the working refrigerant after the change to the existing refrigerant piping. How to Use. 4. When the outdoor unit using the working refrigerant before the change is not operable, a pipe cleaning device having a refrigerant conveying unit and a refrigerant regenerating unit is connected to the outdoor unit, and the outdoor unit is connected to the outdoor unit by the refrigerant conveying unit. Collecting the working refrigerant before the change into a refrigerant recovery cylinder connected to the outlet side of the pipe cleaning device, removing the outdoor unit and the indoor unit using the working refrigerant before the change from the existing refrigerant pipe and Connecting the pipe cleaning device to an existing refrigerant pipe, separating and removing the refrigerating machine oil dissolved in the working refrigerant before change collected in the refrigerant collection cylinder by the refrigerant regenerating means, and the transporting means. Circulating the working refrigerant before the change regenerated by operating for a predetermined time while circulating and washing the existing refrigerant pipe to the existing refrigerant pipe; and 2. A method of using an existing refrigerant pipe according to claim 1, further comprising a step of switching and connecting an outdoor unit and an indoor unit suitable for the working refrigerant. 5. A refrigerant regenerating means comprising: a closed vessel; a regenerative heat exchanger that penetrates downward in the closed vessel; and an inflow pipe and an outgoing pipe that are disposed in the upper part of the closed vessel and open at one end. Comprising a low-temperature and low-pressure liquid refrigerant dissolving refrigerating machine oil flowing into the closed vessel from the inflow pipe, endothermic and evaporate from the refrigerant passing through the regenerative heat exchanger at a high temperature and high pressure by refrigerant conveying means, The method according to claim 3 or 4, wherein the evaporated gas refrigerant returns from the outlet pipe to the refrigerant conveying means and circulates to separate and remove the refrigerating machine oil. 6. The method for utilizing an existing refrigerant pipe according to claim 1, wherein the working refrigerant before the change is circulated in the existing refrigerant pipe in a high-pressure liquid state. 7. The refrigerant according to claim 1, wherein the working refrigerant before the change is a hydrogen fluoride-based refrigerant containing chlorine, and the working refrigerant after the change is a hydrogen-carbon fluoride-based refrigerant containing no chlorine. A method for utilizing an existing refrigerant pipe according to claim 6.