JP4279080B2 - Refrigeration air conditioner and update method thereof - Google Patents

Description

  The present invention relates to a refrigeration air conditioner and an updating method thereof, and more particularly to a refrigeration air conditioning apparatus that updates at least one of a heat source unit and a load side unit using an existing refrigerant pipe and an updating method thereof.

  Conventionally, when renewing a refrigeration air conditioner, there has been a method of replacing only the above unit by using the existing pipe as it is by washing the inside of the extension pipe connecting the heat source side unit and the load side unit. It was. When the washing operation is performed, the refrigerating machine oil that has not been separated by the oil separator flows through the refrigerant circuit, mixes with foreign matter remaining in the existing piping, and accumulates in the accumulator. In conventional refrigeration and air-conditioning equipment, the refrigeration oil in the accumulator is returned to the compressor even during the cleaning operation, so foreign matter in the existing piping is mixed with the refrigeration oil in the compressor, which causes problems with the lubricity of the compressor. Could occur. In view of this, a refrigeration and air-conditioning apparatus has been proposed that includes a foreign matter capturing means in the refrigerant circuit and removes foreign matter from existing piping. (For example, refer to Patent Document 1).

JP 2000-9368 A

  However, in the structure provided with the foreign matter catching means as a separator for separating the foreign matter separately from the accumulator as in the conventional refrigeration air conditioner described above, the heat source side unit becomes large or the heat source side unit is separated from the accumulator. It is necessary to replace the unit, and a large installation space is required. For this reason, it may be difficult to install the heat source unit on construction. In addition, there is a problem that the cost increases due to an increase in the size of the heat source side unit.

  In addition, when performing a cleaning operation by flowing a gas-liquid two-phase refrigerant through an existing pipe, there is a pressure loss in the pipe part and the throttle device, so the cleaning flow cannot be increased, and the existing pipe is cleaned. There was also a problem that the time required for the operation became longer.

  Furthermore, if a refrigerant with a high operating pressure is used during cleaning, the operating pressure of the refrigeration air conditioner may be higher than the allowable pressure of the existing extension pipe, and the operating range of the device is restricted by a pressure switch or the like. When it was provided, there was a possibility that it would fall short of capacity when overloaded.

  The present invention has been made to solve the above-described problems, and can easily update the heat-source side unit and the load-side unit without requiring a large installation space while diverting the existing piping. An object of the present invention is to provide a refrigerating and air-conditioning apparatus that can be used and a method for updating the same.

A refrigerating and air-conditioning apparatus according to the present invention includes a heat source side unit including at least an accumulator, a compressor, a circuit formed by sequentially connecting a heat source side heat exchanger, and an oil return circuit that returns refrigeration oil from the accumulator to the compressor. A load side unit including a first expansion device and a load side heat exchanger, a first extension pipe connecting the heat source side heat exchanger and the first expansion device, and the load side heat exchanger, In the refrigerating and air-conditioning apparatus provided with the second extension pipe for connecting to the compressor, provided in the accumulator, and provided in the oil return circuit, a discharge means for discharging foreign matter in the accumulator after the cleaning operation. during normal operation returns to the compressor by a predetermined amount the refrigerating machine oil by opening the oil return circuit, and an oil return circuit closing means the cleaning during the operation to close the oil return circuit, the heat source-side unit To the cleaning during operation is cooled so that refrigerant liquid or gas-liquid two-phase state that has passed through the heat-source-side heat exchanger during normal cooling operation supercooling degree of the refrigerant that has passed through the heat-source-side heat exchanger a refrigerant heat exchanger to increase, branched from the second extension piping, after being connected to the refrigerant heat exchanger, a bypass circuit for re-joins the second extension piping, during the washing operation, the An opening / closing device that allows the refrigerant on the way to the compressor after passing through the load side heat exchanger to flow into the bypass circuit, and the refrigerant that has passed through the refrigerant heat exchanger from the heat source side heat exchanger side during cooling operation and an auxiliary throttle device to decompress a portion of the time of the cooling operation, in shall refrigerant passed through the auxiliary throttle device is configured to flow into the refrigerant heat exchanger via the bypass circuit is there.

In the refrigerating and air-conditioning apparatus updating method according to the present invention, the existing extension pipe is diverted, and at least the accumulator, the compressor, and the heat source side heat exchanger are sequentially connected, and the refrigerating machine oil is returned from the accumulator to the compressor. A heat source side unit including an oil return circuit, an oil return circuit opening / closing means provided in the oil return circuit, and a discharge means provided in the accumulator; and a load side unit including an expansion device and a load side heat exchanger. The refrigerant that has passed through the heat source side heat exchanger during the cleaning operation is cooled to be in a liquid or gas-liquid two-phase state and passed through the heat source side heat exchanger during normal cooling operation. a refrigerant heat exchanger to increase the supercooling degree of the refrigerant, the second branch from the extension pipe, after being connected to the refrigerant heat exchanger, a bypass times to re merge into the second extension piping If, during the washing operation, in the middle of a refrigerant returning to the compressor after passing through the load-side heat exchanger, an opening and closing device for flow into the bypass circuit, during the cooling operation, from the heat source-side heat exchanger side wherein and an auxiliary throttle device to decompress a portion of the refrigerant passing through the refrigerant heat exchanger, during the cooling operation, so that the refrigerant passed through the auxiliary throttle device flows into the refrigerant heat exchanger via the bypass circuit in order to refrigerating and air-conditioning apparatus that is configured, a unit updating procedure for updating at least one of the load-side unit and the heat source unit, in the refrigerating air conditioning system after the update at least the existing extension in the pipe A evacuation procedure for evacuation, and a refrigerant filling hand that fills at least the existing extension pipe in the updated refrigeration air conditioner with a refrigerant having a higher operating pressure than the collected refrigerant A cleaning operation procedure for performing a cleaning operation for cleaning the inside of the existing extension pipe using the filled refrigerant, and a foreign matter discharging procedure for discharging the foreign matter in the accumulator after the cleaning operation from the discharge port; The normal operation procedure for performing the normal operation after the foreign matter is removed.

In the refrigeration air conditioner of the present invention, a heat source side unit including at least an accumulator, a compressor, a circuit formed by sequentially connecting a heat source side heat exchanger, and an oil return circuit that returns refrigeration oil from the accumulator to the compressor; A load-side unit including a first expansion device and a load-side heat exchanger, a first extension pipe connecting the heat source-side heat exchanger and the first expansion device, the load-side heat exchanger, and the In the refrigerating and air-conditioning apparatus provided with the second extension pipe connecting the compressor, provided in the accumulator, provided in the oil return circuit, a discharge means for discharging foreign matter in the accumulator after the cleaning operation, during normal operation returns to a predetermined amount by the compressor the refrigerating machine oil by opening the oil return circuit, the at the time of cleaning operation, the oil return circuit closing means for closing the oil return circuit, the heat source side unit The cleaning during operation is cooled so that refrigerant liquid or gas-liquid two-phase state that has passed through the heat-source-side heat exchanger, during normal cooling operation the degree of subcooling of the refrigerant passed through the heat-source-side heat exchanger a refrigerant heat exchanger increase, branched from the second extension piping, after being connected to the refrigerant heat exchanger, a bypass circuit for re-joins the second extension piping, during the washing operation, the load An opening / closing device that flows refrigerant into the bypass circuit after passing through the side heat exchanger into the bypass circuit, and refrigerant that has passed through the refrigerant heat exchanger from the heat source side heat exchanger side during cooling operation. and an auxiliary throttle device to decompress a portion, the time in cooling operation, the refrigerant having passed through the auxiliary throttle device is configured to flow into the refrigerant heat exchanger via the bypass circuit Runode, washed Driving is real If it is, by using the accumulator as a separator for separating foreign matter from the refrigerant, to recover the foreign matter in existing pipes into the accumulator, it can be discharged from the discharge port. For this reason, it is possible to update the refrigeration air conditioner without having to enlarge the heat source side unit or replace it with another unit. In addition, gas-liquid two-phase refrigerant can be created so that foreign matters in existing piping can be efficiently removed during cleaning operation, and the efficiency of the refrigeration cycle can be improved by increasing the degree of refrigerant subcooling during cooling operation. Become.

Further, in the refrigerating and air-conditioning apparatus updating method of the present invention, the existing extension pipe is diverted, and at least an accumulator, a compressor, and a heat source side heat exchanger are connected in sequence, and the compressor oil is supplied from the accumulator to the compressor. A return oil return circuit, a return oil circuit opening / closing means provided in the return oil circuit, a heat source side unit including a discharge means provided in the accumulator, and a load side unit including a throttling device and a load side heat exchanger. The refrigerant that has passed through the heat source side heat exchanger during the cleaning operation is cooled in a liquid or gas-liquid two-phase state, and passes through the heat source side heat exchanger during normal cooling operation. a refrigerant heat exchanger to increase the supercooling degree of the refrigerant, and branched from the second extension piping, after being connected to the refrigerant heat exchanger, again merge into the second extension piping bypass And a circuit, during the washing operation, in the middle of a refrigerant returning to the compressor after passing through the load-side heat exchanger, an opening and closing device for flow into the bypass circuit, during the cooling operation, from the heat source-side heat exchanger side and an auxiliary throttle device to decompress a portion of the refrigerant passing through the refrigerant heat exchanger, during the cooling operation, the refrigerant having passed through the auxiliary throttle device flows into the refrigerant heat exchanger via the bypass circuit to the refrigerating and air-conditioning apparatus that is configured to, the heat source-side unit and the unit updating procedure for updating at least one of the load-side unit, in the refrigerating air conditioning system after the update at least the existing extension in the pipe Evacuation procedure for evacuating the refrigerant, and at least the existing extension pipe in the updated refrigeration air conditioner is charged with a refrigerant having a higher operating pressure than the recovered refrigerant. A cleaning operation procedure for performing a cleaning operation for cleaning the inside of the existing extension pipe using the filled refrigerant, and a foreign matter discharging procedure for discharging the foreign matter in the accumulator after the cleaning operation from the discharge port And after the foreign matter has been removed, a series of procedures consisting of a normal operation procedure for performing a normal operation is performed, so that the cleaning operation can be completed efficiently and in a short time. Can be updated.

  Embodiments of the present invention will be described below with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and the description thereof is omitted or simplified as appropriate.

Embodiment 1 FIG.
1 is a refrigerant circuit diagram of a refrigerating and air-conditioning apparatus according to Embodiment 1 of the present invention. The refrigerant circuit shown in FIG. 1 includes a heat source side unit 1 and a load side unit 2. The heat source side unit 1 and the load side unit 2 are connected by a first extension pipe 3 (liquid side refrigerant pipe) and a second extension pipe 4 (gas side refrigerant pipe) to constitute a refrigerant circuit. .

  The heat source side unit 1 includes an accumulator 5, a compressor 6, an oil separator 7, a four-way valve 8, a heat source side heat exchanger 9, and a refrigerant heat exchanger 10, which are sequentially connected to each other on the heat source side. The main circuit of the unit 1 is configured. In addition, an oil return circuit 12 connected between the accumulator 5 and the compressor 6 via an oil return capillary 11 is provided at the lower part of the oil separator 7. The heat source side unit 1 is provided with a hot gas bypass circuit 14 that branches between the oil separator 7 and the four-way valve 8 and is connected to the lower part of the accumulator 5 via an opening / closing device 13. Further, an oil return circuit 15 connected between the accumulator 5 and the compressor 6 is provided below the accumulator 5. A discharge port 16 for discharging the refrigerating machine oil accumulated in the accumulator 5 is provided on the side surface of the accumulator 5. Further, the heat source side unit 1 is provided with an oil return circuit opening / closing means 17 for opening and closing the oil return circuit 15 in the oil return circuit 15.

The refrigerating and air-conditioning apparatus according to the present embodiment is provided with the oil return circuit opening / closing means 17 and closes the oil return circuit opening / closing means 17 during the cleaning operation, so that the inflow of the refrigerating machine oil from the accumulator 5 to the compressor 6 can be prevented. it can. For this reason, the situation where the foreign material in existing piping mixes with the refrigeration oil in the compressor 6, and the problem which arises in the lubricity of the compressor 6 can be avoided. Further, during normal cooling operation or heating operation, the oil return circuit opening / closing means 17 is opened to a predetermined opening in order to return the refrigerating machine oil in the accumulator 5 to the compressor 6.
Further, the heat source unit 1 is provided with a bypass circuit 19 that branches between the second extension pipe 4 and the four-way valve 8 and is connected to the refrigerant heat exchanger 10 via a check valve 18. An opening / closing device 20 is provided for allowing the refrigerant to flow into the bypass circuit 19 during the cleaning operation. Further, the heat source side unit 1 is provided with an auxiliary throttle device 21 that decompresses part of the liquid refrigerant that has flowed out of the heat source side heat exchanger 9 and the refrigerant heat exchanger 10 during the cooling operation.

  Further, in the example of the refrigerating and air-conditioning apparatus of the present embodiment shown in FIG. Are connected in series.

Next, referring to FIG. 2, the first extension pipe 3 and the second extension pipe 4 which are existing refrigerant pipes are diverted, and the existing heat source side unit and load side unit have the above refrigerant circuit configuration. An outline of the update procedure when updating to the heat source side unit 1 and the load side unit 2 will be described.
In FIG. 2, first, as STEP 1, the refrigerant is recovered from the existing heat source side unit and load side unit. In STEP 2 (unit update procedure), the heat source side unit and the load side unit are updated to new units. In STEP 3 (evacuation procedure), the existing piping side is evacuated. In STEP 4 (refrigerant filling procedure), the refrigerant is charged on the existing piping side that has been evacuated. Here, the refrigerant to be charged is a refrigerant whose operating pressure of the refrigeration cycle is higher than the refrigerant charged in the existing unit. In STEP 5 (cleaning operation procedure), the oil return circuit opening / closing means 17 is fully closed, the compressor 6 is operated, and a cooling operation or a heating operation is performed to clean the existing piping for a predetermined time. By performing the washing operation in STEP 5, the foreign matter in the existing pipe is taken into the refrigerant and removed. The refrigerant containing the foreign matter is then separated from the foreign matter in the accumulator 5 and collected in the accumulator 5. In STEP 6 (foreign matter discharge procedure), the foreign matter collected in the accumulator 5 is discharged from the discharge port 16. By executing the above procedure, the trial operation that also serves as the cleaning operation at the time of updating is completed, and foreign matters in the existing piping can be removed. Thereafter, in STEP 7 (normal operation procedure), the oil return circuit opening / closing means 17 is opened to a predetermined opening, and normal cooling or heating operation is started.

Next, the cleaning operation in STEP 5 will be described in detail. Here, the operation of the cleaning operation using the cooling operation will be described with reference to FIG. During the cleaning operation, the compressor 6 is operated with the oil return circuit opening / closing means 17 fully closed. The high-temperature and high-pressure gas refrigerant discharged from the compressor 6 flows to the heat source side heat exchanger 9 via the four-way valve 8. In the heat source side heat exchanger 9, the gas refrigerant dissipates a heat amount close to sensible heat to become a saturated gas and reaches the refrigerant heat exchanger 10. The refrigerant heat exchanger 10 exchanges heat with the refrigerant flowing on the low pressure side, condenses and liquefies, and becomes a liquid or gas-liquid two-phase refrigerant. As the refrigerant in the gas-liquid two-phase state flows through the first extension pipe 3 , the first expansion device 22, the load-side heat exchanger 23 and the second extension pipe 4 in this order, the first pipe which is an existing pipe is used. The foreign matter remaining in the extension pipe 3 and the second extension pipe 4 is taken into the refrigerant and removed. The refrigerant containing foreign matter in the existing pipe returns to the heat source side unit 1 and flows into the refrigerant heat exchanger 10 via the check valve 18 because the opening / closing device 20 is closed. Thereafter, the liquid refrigerant is evaporated by the refrigerant heat exchanger 10 and taken into the accumulator 5 through the four-way valve 8, and foreign substances in the gas refrigerant are separated by the accumulator 5. The gas refrigerant from which the foreign matter has been separated returns to the compressor 6, is compressed again, and is discharged from the compressor 6. In the refrigeration air conditioner of the present embodiment, the oil return circuit opening / closing means 17 in the oil return circuit 15 is provided. Since it is closed, the foreign matter in the accumulator 5 is collected in the accumulator 5 without being sucked into the compressor 6.

  By performing the above cleaning operation, foreign matter in the existing piping can be collected in the accumulator 5. Thereafter, the foreign matter in the existing piping collected in the accumulator 5 is discharged from the discharge port 16. By these operations, foreign matters in the existing piping can be removed, so that it is possible to eliminate poor lubrication due to mixing of foreign matters in the existing piping and malfunctions of valves due to foreign matter being caught. In addition, the foreign matter does not return from the accumulator 5 to the compressor 6 through the oil return circuit 15 during the cleaning operation, so that the foreign matter can be reliably removed from the existing piping, and the reliability of the system that uses the existing piping is reliable. Can be improved.

Next, the operation when carrying out the normal cooling operation in STEP 7 will be described in detail.
In FIG. 1, when the compressor 6 is driven, high-temperature and high-pressure gas refrigerant is discharged from the compressor 6 and condensed and liquefied by the heat source side heat exchanger 9 via the oil separator 7 and the four-way valve 8. The liquefied refrigerant is further cooled by the refrigerant heat exchanger 10 to increase the degree of supercooling. Part of the liquid refrigerant that has flowed out of the refrigerant heat exchanger 10 is throttled to a low pressure by the auxiliary throttle device 21 and then condenses in the liquid refrigerant and heat condensed in the heat source side heat exchanger 9 when passing through the refrigerant heat exchanger 10. It is exchanged and evaporates and vaporizes itself. The remaining liquid refrigerant increased degree of subcooling in the refrigerant heat exchanger 10, the first extension piping 3 flow is throttled by the first throttle device 22 to a low pressure, through the load-side heat exchanger 23. The low-pressure gas-liquid two-phase refrigerant that has flowed to the load side heat exchanger 23 evaporates and vaporizes, flows through the second extension pipe 4 , and returns to the heat source side unit 1. The gas refrigerant returned to the heat source side unit 1 merges with the gas refrigerant evaporated and vaporized in the refrigerant heat exchanger 10 via the opening / closing device 20, and then returns to the compressor 6 via the four-way valve 8 and the accumulator 5. Note that most of the refrigerating machine oil taken out together with the refrigerant when the refrigerant flows out of the compressor 6 is separated by the oil separator 7 and returned to the suction side of the compressor 6 through the oil return capillary 11. The refrigerating machine oil that has flowed out of the heat source side unit 1 without being separated by the oil separator 7 circulates in the refrigerant circuit together with the refrigerant, returns to the heat source side unit 1 again, and temporarily accumulates in the accumulator 5. Here, the refrigerating machine oil in the accumulator 5 is returned to the compressor 6 by a predetermined amount because the oil return circuit opening / closing means 17 is adjusted to a predetermined opening degree.

Next, the operation when carrying out the normal heating operation in STEP 7 will be described in detail.
In FIG. 1, when the compressor 6 is driven, high-temperature and high-pressure gas refrigerant is discharged from the compressor 6 and flows to the second extension pipe 4 through the oil separator 7, the four-way valve 8, and the opening / closing device 20. . Here, the high-temperature and high-pressure gas refrigerant that has flowed through the second extension pipe 4 is condensed and liquefied by the load-side heat exchanger 23. The refrigerant liquefied by the load side heat exchanger 23 is throttled to a low pressure by the first throttling device 22, then flows to the first extension pipe 3 and returns to the heat source side unit 1. The gas-liquid two-phase refrigerant returned to the heat source side unit 1 evaporates and vaporizes in the heat source side heat exchanger 9 and then returns to the compressor 6 via the four-way valve 8 and the accumulator 5. Note that most of the refrigerating machine oil taken out together with the refrigerant when the refrigerant flows out of the compressor 6 is separated by the oil separator 7 and returned to the suction side of the compressor 6 through the oil return capillary 11. The refrigeration oil that has flowed out of the heat source side unit 1 without being separated by the oil separator 7 circulates in the refrigerant circuit together with the refrigerant, returns to the heat source side unit 1 again, temporarily accumulates in the accumulator 5, and the refrigeration oil in the accumulator 5 is Since the oil return circuit opening / closing means 17 is adjusted to a predetermined opening, it is returned to the compressor 6 by a predetermined amount.

  As described above, according to the refrigerating and air-conditioning apparatus of the present embodiment, the oil return circuit opening / closing means 17 is provided in the oil return circuit 15, so that the accumulator 5 is used as a separator for separating foreign substances from the refrigerant during the cleaning operation. can do. For this reason, it is not necessary to newly add a separator to the heat source side unit 1, and the heat source side unit and the load side unit can be updated by diverting existing piping. Further, it is possible to prevent the updated heat source side unit from becoming large, and a new installation space is not required when installing the updated unit. Also, by washing the existing piping with a refrigerant that has a higher operating pressure than the refrigerant charged in the existing unit, the pressure loss in the piping can be reduced and more refrigerant flow can be made. It is possible to efficiently collect the foreign matter, and renewal work is possible in a short construction period.

  Further, in the conventional refrigeration air conditioner, when the capacity of the unit is increased using existing piping, or when the position of the unit is installed at a position far from the position of the existing unit, the refrigerant circulation amount increases. Since the pipe length is increased, the pressure loss of the pipe is increased, so that the efficiency of the refrigeration cycle is lowered. Furthermore, in general, when the same refrigerant is used, the flow rate of the refrigerant increases as the capacity increases. Therefore, in order to make the pressure loss in the extension pipe constant, it is necessary to increase the pipe diameter of the extension pipe as the capacity increases. there were. In contrast, in the refrigerating and air-conditioning apparatus of this embodiment, the pressure loss of the piping is reduced by taking the operating pressure of the refrigerant after the update higher than the operating pressure of the refrigerant before the update. Even if the capacity of the unit to be increased is increased, the pressure loss of the piping can be made equal to the case of operating with the existing unit. Therefore, even when the heat load increases, it is possible to easily increase the capacity of the unit by diverting the existing piping, and also to ensure the same energy saving as before without deteriorating the efficiency. . Also, for the convenience of installation, even if the position of the heat source side unit or load side unit is changed and the pipe length is longer than the existing unit, a refrigerant with a higher operating pressure than the refrigerant charged in the existing unit is used. By filling and cleaning the existing piping, the pressure loss of the piping can be made equal to or lower than before, so that the degree of freedom of unit installation at the time of renewal can be expanded.

  In addition, since the refrigerating and air-conditioning apparatus of the present embodiment includes the refrigerant heat exchanger 10, in STEP5, it is possible to create a gas-liquid two-phase refrigerant so that foreign matters in the existing piping can be efficiently removed during the cleaning operation. In the cooling operation, by increasing the supercooling degree of the refrigerant, the refrigerant flow rate flowing through the load side unit 2 is decreased, thereby reducing the pressure loss in the gas pipe (second extension pipe 4) and improving the efficiency of the refrigeration cycle. Can be improved. That is, the refrigerant heat exchanger 10 has a function of creating a gas-liquid two-phase refrigerant so that foreign matters can be collected efficiently when collecting foreign matters in the existing piping, and increases the degree of supercooling of the refrigerant during normal cooling operation. Thus, by providing the function of improving the efficiency of the refrigeration cycle, it is possible to contribute to the reduction of mountability and cost of the refrigeration cycle.

  Furthermore, when updating from the existing heat source side unit to the heat source side unit 1 of the present embodiment, an auxiliary heat exchanger is connected to the heat source side unit 1 according to the allowable pressure of the piping to suppress an increase in high pressure. It is also possible to ensure safety when using a refrigerant having a high operating pressure using existing piping.

  In the case of a circuit configuration that does not include the refrigerant heat exchanger 10 in FIG. 1, the washing operation of STEP 5 may be performed by a normal cooling operation or heating operation. In the refrigerating and air-conditioning apparatus of the present embodiment, the accumulator 5 is used as a separator that separates foreign matters from the refrigerant during the washing operation in STEP 5, but a container for separating other foreign matters is provided in addition to the accumulator 5, During the washing operation in STEP5, the foreign matter is separated from the refrigerant and collected in the container while preventing the foreign matter from flowing out again to the compressor 6 by closing the opening / closing means provided at the inlet / outlet of the container. Is also possible.

  In addition, when the refrigerant used in the existing unit is a refrigerant containing chlorine such as R22 and the updated refrigerant is a refrigerant not containing chlorine such as R410A, the ozone depletion coefficient may be zero. It can also help protect the ozone layer. Furthermore, when the refrigerant used in the existing unit is R407C and the refrigerant after renewal is R32, the renewal reduces the global warming potential, which helps to prevent global warming.

Embodiment 2. FIG.
FIG. 3 is a refrigerant circuit diagram of the refrigerating and air-conditioning apparatus according to Embodiment 2 of the present invention. The portions having the same functions and configurations as those in FIG. 1 showing the refrigerant circuit of the first embodiment in FIG. 3 are denoted by the same symbols, and detailed description thereof is omitted or simplified.

  As shown in FIG. 3, in the refrigerating and air-conditioning apparatus according to the second embodiment, the heat source side unit 24 includes a second expansion device 25, a first pressure sensor 26, and a second pressure sensor 27. The second expansion device 25 is arranged in the pipe where the refrigerant is directed from the refrigerant heat exchanger 10 toward the load side unit 2 during the cooling operation, and further downstream from the branch point to the auxiliary expansion device 21. The first pressure switch 26 for measuring the refrigerant pressure in the first extension pipe 3 is provided at a position downstream of the second expansion device 25 during the cooling operation. A second pressure switch 27 that measures the discharge pressure of the compressor 6 is provided between the compressor 6 and the oil separator 7.

  In the second embodiment, it is assumed that the compressor 6 can vary the operating frequency with an inverter (not shown). Further, the heat source side unit 24 is a unit having a capacity approximately 1.2 times that of the existing unit, the refrigerant used in the existing unit is R22, and the refrigerant used in the new unit is R410A. And

  In the refrigerating and air-conditioning apparatus according to the second embodiment, the piping pressure is measured by the first pressure switch 26 and the second pressure switch 27 in consideration of the allowable pressure of the existing piping, so that the cooling operation or heating can be performed. Control is performed so that the piping pressure does not exceed the allowable pressure during operation. According to the refrigerating and air-conditioning apparatus of the present embodiment having the above configuration, foreign matters in the existing piping can be removed by performing the same operation as the cleaning operation in the first embodiment. Hereinafter, an operation when the cooling operation and the heating operation in the present embodiment are performed will be described.

  First, when performing the cooling operation, the compressor 6 is driven, high-temperature and high-pressure gas refrigerant is discharged from the compressor 6, and is condensed and liquefied by the heat source side heat exchanger 9 through the four-way valve 8. The liquefied refrigerant increases the degree of supercooling in the refrigerant heat exchanger 10 and flows out of the refrigerant heat exchanger 10. A part of the liquid refrigerant that has flowed out of the refrigerant heat exchanger 10 is throttled to a low pressure via the auxiliary throttle device 21, and exchanges heat with the liquid refrigerant condensed in the heat source side heat exchanger 9 in the refrigerant heat exchanger 10. Evaporate and vaporize. The remaining liquid refrigerant whose degree of supercooling has been increased by the refrigerant heat exchanger 10 is reduced to the allowable pressure of the first extension pipe 3 by the second expansion device 25. Here, the allowable pressure of the first extension pipe 3 is investigated in advance and stored in the storage means (not shown) of the heat source side unit 24, and the measurement result of the first pressure sensor 26 during the cooling operation is appropriately selected. And the opening degree of the second expansion device 25 is determined. The degree of supercooling applied to the liquid refrigerant by the refrigerant heat exchanger 10 is such that the refrigerant boiles under reduced pressure due to the pressure loss of the first extension pipe 3, and the state of the refrigerant at the inlet of the first expansion device 22 is gas-liquid two-phase. It shall be 10K or more so as not to be in a state. The liquid refrigerant decompressed by the second expansion device 25 flows through the first extension pipe 3, is throttled to a low pressure by the first expansion device 22, and flows to the load side heat exchanger 23. The low-pressure gas-liquid two-phase refrigerant that has flowed to the load-side heat exchanger 23 evaporates and vaporizes, flows through the second extension pipe 4, and returns to the heat source-side unit 24. The gas refrigerant returned to the heat source side unit 24 merges with the gas refrigerant evaporated and vaporized by the refrigerant heat exchanger 10 via the opening / closing device 20, and then returns to the compressor 6 via the four-way valve 8 and the accumulator 5. Most of the refrigerating machine oil taken out together with the refrigerant when the refrigerant flows out of the compressor 6 is separated by the oil separator 7 and returned to the suction side of the compressor 6 through the oil return capillary 11. The refrigerating machine oil that has flowed out of the heat source unit 24 without being separated by the oil separator 7 circulates in the refrigerant circuit together with the refrigerant, returns to the heat source unit 24 again, and temporarily accumulates in the accumulator 5. Here, the refrigerating machine oil in the accumulator 5 is returned to the compressor 6 by a predetermined amount by the oil return circuit opening / closing means 17.

When the heating operation is performed, the compressor 6 is driven, and high-temperature and high-pressure gas refrigerant is discharged from the compressor 6 and flows to the second extension pipe 4 through the four-way valve 8 and the opening / closing device 20. Here, the allowable pressure of the second extension pipe 4 is investigated in advance and stored in the storage means (not shown) of the heat source side unit 24, and the measurement result of the second pressure sensor 27 during the heating operation as appropriate. The number of rotations of the compressor 6 is controlled by increasing or decreasing the operating frequency with an inverter. The high-temperature and high-pressure gas refrigerant that has flowed through the second extension pipe 4 is condensed and liquefied by the load-side heat exchanger 23. The refrigerant liquefied by the load side heat exchanger 23 is throttled to a low pressure by the first throttle device 22, flows to the first extension pipe 3, and returns to the heat source side unit 24. The refrigerant in the gas-liquid two-phase state that has returned to the heat source side unit 24 evaporates and vaporizes in the heat source side heat exchanger 9 and then returns to the compressor 6 via the four-way valve 8 and the accumulator 5. Most of the refrigerating machine oil taken out together with the refrigerant when the refrigerant flows out of the compressor 6 is separated by the oil separator 7 and returned to the suction side of the compressor 6 through the oil return capillary 11. The refrigerating machine oil that has flowed out of the heat source unit 24 without being separated by the oil separator 7 circulates in the refrigerant circuit together with the refrigerant, returns to the heat source unit 24 again, and temporarily accumulates in the accumulator 5. Here, the refrigerating machine oil in the accumulator 5 is returned to the compressor 6 by a predetermined amount by the oil return circuit opening / closing means 17.

  As described above, according to the refrigerating and air-conditioning apparatus of the present embodiment, even when a refrigerant having a higher operating pressure than the allowable pressure of the existing piping is used by controlling the piping pressure in consideration of the allowable pressure of the existing piping. The operation of the refrigeration cycle in compliance with the allowable piping pressure can be ensured, and the refrigeration cycle can be operated safely.

Moreover, when comparing the gas densities of R22 and R410A, R22 is about 21.23 kg / m ³ at 0 ° C., whereas R410A has a density of about 1.44 times, about 30.48 at 0 ° C. is there. Here, if the mass flowing in the unit time is the same, the speed of the refrigerant flowing through the gas pipe (second extension pipe 4) decreases. For this reason, the refrigerating machine oil that has flowed into the pipe is less likely to move due to the refrigerant flow (shearing force), and when the pipe used in R22 is replaced with a heat source side unit of the same capacity when used in R410A. Refrigerator oil tends to remain in the pipe. On the other hand, by setting the capacity of the heat source side unit of the system using R410A to about 1.2 times or more, the shear force acting between the refrigerating machine oil remaining in the gas pipe and the gas refrigerant becomes the first power of the density of the refrigerant. Since the relationship is proportional to the square of the speed of the refrigerant, the shearing force acting on the refrigerant and the refrigerating machine oil in the gas pipe can be made substantially equal between R22 and R410A, and the oil return of the refrigerating machine oil in the gas pipe Reliability can be the same for both R22 and R410A.

It is a refrigerant circuit diagram of the refrigerating and air-conditioning apparatus according to Embodiment 1 of the present invention. It is a figure for demonstrating the unit update procedure of the refrigeration air conditioning apparatus which concerns on Embodiment 1 of this invention. It is a refrigerant circuit diagram of the refrigerating and air-conditioning apparatus according to Embodiment 2 of the present invention.

Explanation of symbols

  1, 24 Heat source side unit, 2 Load side unit, 3 First extension pipe, 4 Second extension pipe, 5 Accumulator, 6 Compressor, 7 Oil separator, 8 Four-way valve, 9 Heat source side heat exchanger, 10 Refrigerant heat exchanger, 11 oil return capillary, 12 oil return circuit, 13 switchgear, 14 hot gas bypass circuit, 15 oil return circuit, 16 discharge port, 17 oil return circuit open / close means, 18 check valve, 19 bypass circuit 20 Opening and closing device, 21 Auxiliary throttle device, 22 First throttle device, 23 Load side heat exchanger, 25 Second throttle device, 26 First pressure switch, 27 Second pressure switch

Claims (7)

A heat source side unit including at least an accumulator, a compressor, a circuit formed by sequentially connecting a heat source side heat exchanger, and an oil return circuit for returning refrigeration oil from the accumulator to the compressor;
A load side unit including a first expansion device and a load side heat exchanger;
A first extension pipe connecting the heat source side heat exchanger and the first expansion device;
In the refrigeration air conditioner comprising the second extension pipe connecting the load side heat exchanger and the compressor,
Discharging means provided in the accumulator for discharging foreign matter in the accumulator after a cleaning operation;
An oil return circuit opening / closing means provided in the oil return circuit, which opens the oil return circuit during normal operation and returns the refrigerating machine oil to the compressor by a predetermined amount, and closes the oil return circuit during the cleaning operation; ,
In the heat source side unit, the refrigerant that has passed through the heat source side heat exchanger during the cleaning operation is cooled so as to be in a liquid or gas-liquid two-phase state, and during the normal cooling operation, the refrigerant that has passed through the heat source side heat exchanger. a refrigerant heat exchanger to increase the supercooling degree of
A bypass circuit branched from the second extension pipe and connected to the refrigerant heat exchanger, and then joined again to the second extension pipe;
An opening / closing device for causing the refrigerant on the way to return to the compressor after passing through the load-side heat exchanger to flow into the bypass circuit during the cleaning operation;
During the cooling operation, an auxiliary throttle device to decompress a portion of the refrigerant passing through the refrigerant heat exchanger from the heat source-side heat exchanger side,
Wherein during cooling operation, the refrigerating air conditioning system refrigerant passed through the auxiliary throttle device is characterized that you have configured to flow into the refrigerant heat exchanger through the bypass circuit.   An oil separator that separates the refrigerating machine oil that flows out of the compressor together with the refrigerant from the refrigerant between the compressor and the four-way valve, and the refrigerating machine oil separated by the oil separator through an oil return capillary. The refrigerating and air-conditioning apparatus according to claim 1, further comprising an oil return circuit that returns to the compressor. A second expansion device provided in a pipe between the heat source side heat exchanger and the first expansion device, a first pressure sensor for measuring a pressure in the first extension pipe, and Storage means for storing the allowable pressure of the first extension pipe,
The refrigerating and air-conditioning apparatus according to claim 1 or 2, wherein the opening degree of the second expansion device is set so that the pressure in the first extension pipe is equal to or lower than an allowable pressure. A second pressure sensor for measuring the discharge pressure of the compressor, and storage means for storing an allowable pressure of the second extension pipe,
Based on the relationship between the discharge pressure of the compressor and the allowable pressure of the second extension pipe, controlling the rotation speed of the compressor so that the pressure in the second extension pipe is equal to or lower than the allowable pressure. The refrigeration air conditioner according to any one of claims 1 to 3. An existing extension pipe is used, and at least an accumulator, a compressor, and a heat source side heat exchanger are connected in sequence, an oil return circuit that returns refrigeration oil from the accumulator to the compressor, and an oil return circuit. A heat source side unit including an oil return circuit opening / closing means and a discharge means provided in the accumulator, and a load side unit including a throttling device and a load side heat exchanger, and the heat source side unit includes the heat source side unit during the cleaning operation. A refrigerant heat exchanger that cools the refrigerant that has passed through the heat source side heat exchanger so as to be in a liquid or gas-liquid two-phase state and increases the degree of supercooling of the refrigerant that has passed through the heat source side heat exchanger during normal cooling operation If, branched from the second extension piping, after being connected to the refrigerant heat exchanger, a bypass circuit for re-joins the second extension piping, during the washing operation, the load-side heat exchanger The middle of the refrigerant returning to the compressor after passing through the opening and closing device for flow into the bypass circuit, during cooling operation, reduced pressure a portion of the refrigerant passing through the refrigerant heat exchanger from the heat source-side heat exchanger side is to an auxiliary expansion device, when the cooling operation, in the refrigerant having passed through the auxiliary throttle device to the refrigeration air conditioning system that is configured to flow into the refrigerant heat exchanger via the bypass circuit A unit update procedure for updating at least one of the heat source unit and the load unit;
A evacuation procedure for evacuating at least the existing extension pipe in the refrigerating and air-conditioning apparatus after the update;
A refrigerant charging procedure for charging a refrigerant having a higher operating pressure than the recovered refrigerant into at least the existing extension pipe in the refrigerating and air-conditioning apparatus after the update,
Using this filled refrigerant, a cleaning operation procedure for performing a cleaning operation for cleaning the inside of the existing extension pipe,
Foreign matter discharge procedure for discharging foreign matter in the accumulator after the cleaning operation from the discharge port;
A method for updating a refrigerating and air-conditioning apparatus, comprising: a normal operation procedure for performing normal operation after the foreign matter is removed.   6. The method for updating a refrigerating and air-conditioning apparatus according to claim 5, wherein in the cleaning operation procedure, the cleaning operation is performed by closing the oil return circuit opening / closing means.   In the said unit update procedure, it updates to the heat-source side unit provided with an auxiliary heat exchanger, The update method of the refrigeration air conditioner of Claim 5 or 6 characterized by the above-mentioned.

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