JP4420871B2 - Refrigeration air conditioner - Google Patents

Description

  The present invention relates to a refrigeration air conditioner that connects a heat source side unit and a load side unit using an existing refrigerant pipe, and relates to a refrigeration air conditioner that can perform an air conditioning operation while washing the existing refrigerant pipe in a heating operation.

The conventional heat storage type air conditioner replaces only the heat source side unit and the load side unit, and bypasses the refrigerant pipe of the heat source side unit without replacing the connection pipe connecting the heat source side unit and the load side unit. In this bypass path, foreign matter catching means is provided, and during the cleaning operation, the refrigerant is passed through the existing refrigerant pipe and load side heat exchanger as a gas-liquid two-phase refrigerant by the cooling means to remove and collect the foreign matter. The refrigerant that has returned to the path is evaporated by the heating means, and the foreign substance that remains as a liquid is separated and collected by the foreign substance capturing means (see, for example, Patent Document 1).

JP 2000-009368 A (paragraphs 0089 to 0108, FIG. 7)

  In the heating operation, if the heat exchange amount between the cooling means and the heating means is not well balanced, there is a problem that the operation of the refrigeration cycle becomes overheated, the high and low pressures are lowered, and the refrigerant flow rate is likely to decrease. In addition, there is a problem that the bypass circuit is complicated and expensive, and the heat source side unit is enlarged.

  In addition, the refrigeration oil taken out together with the refrigerant from the compressor during cleaning is taken out into the refrigerant circuit without being separated by the oil separator, and is collected in the foreign matter catcher together with contamination such as mineral oil in the refrigerant circuit. There was a possibility of running out of refrigeration oil in the machine. Moreover, in order to supplement these, although it is possible to replenish refrigeration oil from the outside, there was a problem that it took time and effort.

  The present invention has been made to solve such a problem, and an object thereof is to obtain a refrigerating and air-conditioning apparatus capable of performing a heating operation with a load-side heat exchanger even in a cleaning operation with a simple configuration.

The refrigeration air conditioner according to the present invention is a refrigeration air conditioner in which a new heat source side unit and a load side unit are connected by an existing refrigerant pipe. The new heat source side unit includes a compressor, a heat source side heat exchanger, a refrigerant. At least a heat exchanger and an accumulator are mounted, and the new load unit includes at least a throttle means and a load side heat exchanger. The refrigerant heat exchanger includes the heat source side heat exchanger and the throttle means. Between the load side heat exchanger and the refrigerant between the accumulator, and the refrigerant between the load side heat exchanger and the accumulator. The refrigerant heat exchanger generates a gas-liquid two-phase refrigerant capable of air-conditioning operation while executing the cleaning operation to be recovered .

  According to this invention, with a simple configuration, the load-side heat exchanger can perform an air conditioning operation even in a cleaning operation.

Embodiment 1 FIG.
FIG. 1 is a refrigerant circuit diagram of a refrigerating and air-conditioning apparatus showing Embodiment 1 of the present invention.
In FIG. 1, the refrigerant air conditioner includes a liquid refrigerant pipe 28 (hereinafter referred to as a liquid pipe 28) in which a heat source side unit A and a load side unit B are existing pipes, and an existing gas refrigerant pipe 29 (hereinafter referred to as gas pipe 29). And the refrigerant circuit is configured.

The main circuit of the heat source side unit A is configured by sequentially connecting the accumulator 8, the compressor 1, the oil separator 9, the four-way valve 2, the heat source side heat exchanger 3, and the refrigerant heat exchanger 18.
In the heat source side unit A, an oil return capillary 20a is connected between the lower part of the oil separator 9 and the suction pipe of the compressor 1, and a refrigerant circuit between the lower part of the oil separator 9 and the oil return capillary 20a is provided. The branched pipe and the upper part of the oil tank 17 are connected via an oil return solenoid valve 15a, and another upper part of the oil tank 17 and a compressor suction pipe are connected. Further, the lower portion of the oil tank 17 and the compressor suction pipe are connected via an oil return solenoid valve 15b.

The refrigerant heat exchanger 18 includes a heat source side heat exchanger 3, a ball valve 4 on the liquid refrigerant pipe side, a refrigerant pipe of an electromagnetic valve 14b connected via a pressure regulating valve 22, a four-way valve 2 and a gas refrigerant pipe side. Provided between the ball valve 7 and heat exchange of both refrigerants.
An electromagnetic valve 14 a that bypasses the electromagnetic valve 14 b and the refrigerant heat exchanger 18 is connected between the refrigerant pipe between the electromagnetic valve 14 b and the pressure regulating valve 22 and the heat source side heat exchanger 3. A flow rate adjusting valve 19 is provided in the oil return circuit connected from the lower part of the accumulator 8 to the suction pipe of the compressor.

  Further, a pressure switch 23a whose operating pressure is set to a high design pressure is provided downstream of the oil separator 9, and pressure switches 23b and 23c set to operating pressures corresponding to the pressure resistance of the existing liquid pipe 28 and gas pipe 29. Is provided. Further, a pressure sensor 24a is provided in the high pressure portion downstream of the oil separator 9, a pressure sensor 24b is provided downstream of the pressure regulating valve 22 in the liquid piping, and a pressure sensor 24c is provided in the low pressure portion. Further, a temperature sensor 25a for measuring the discharge temperature of the compressor 1, a temperature sensor 25b for measuring the temperature of the liquid refrigerant pipe, a temperature sensor 25c for measuring the pipe temperature between the refrigerant heat exchanger 18 and the pressure regulating valve 22, and an accumulator. A temperature sensor 25d for measuring the intake temperature 8 is provided.

  The load side unit B includes load side heat exchangers 6a and 6b and expansion devices 5a and 5b. Further, temperature sensors 26a and 26b for measuring the refrigerant pipe temperature between the load side heat exchangers 6a and 6b and the expansion devices 5a and 5b, and a temperature sensor 27a for measuring the temperature of the gas pipe of the load side heat exchangers 6a and 6b. 27b are provided.

  Next, a method for storing oil in the oil tank 17 in advance will be described with reference to FIG. The compressor 1 is preliminarily filled with an amount of refrigerating machine oil that is assumed to be oil taken into the refrigerant circuit during cleaning. If the refrigerating machine oil does not enter the compressor 1, it may be put in the refrigerant circuit, for example, in the accumulator 8. Next, a dummy heat exchanger is connected to the liquid-side ball valve 4 and the gas-side ball valve 7 of the heat source side unit A, or the liquid-side ball valve 4 and the gas-side ball valve 7 are short-circuited to perform triangular operation. When the oil return solenoid valve 15a is opened, the oil return solenoid valve 15b is closed, and the compressor 1 is started, the refrigerating machine oil taken out from the compressor 1 is separated by the oil separator 9, and the oil tank Enter 17. The refrigerant gas and the refrigeration oil are separated in the oil tank 17, the refrigeration oil stays in the oil tank 17, and the refrigerant gas returns to the compressor suction via the oil return solenoid valve 15a. By continuing this operation for a certain period of time, refrigeration oil is stored in the oil tank 17 and the oil return solenoid valves 15a and 15b are closed and shipped.

  Next, the flow from the construction of the unit on site until the start of air conditioning operation will be described with reference to FIG. In STEP 1 after construction, the operation is started by a start switch provided in the outdoor unit or indoor unit of the unit. Here, until the series of cleaning operations is completed, the compressor is prevented from rotating even if the control remote controller is pressed by mistake. Further, when the remote controller is pressed when a series of cleaning operations are not completed, the cleaning operation may be automatically started.

  In STEP2, the operation mode is determined. In determining the operation mode, as shown in FIG. 3, the room air temperature and the outdoor air temperature are divided into regions, and in which region in FIG. 3 the detected values of the indoor air temperature and the outdoor air temperature at the start of operation correspond. And set it automatically. Further, in consideration of the indoor environment to be air-conditioned, a switch for the user to manually determine the mode may be provided.

  In STEP 3, the compressor 1 is started and the cleaning operation is started. First, the operation when operating in the cooling cycle will be described. When the compressor 1 is operated, the high-temperature and high-pressure gas refrigerant is separated from the refrigeration oil taken out from the compressor 1 by the oil separator 9, and the refrigerant gas is condensed and liquefied by the heat source side heat exchanger 3 via the four-way valve 2. Is done. The refrigerating machine oil separated by the oil separator 9 flows into the suction pipe of the compressor 1 through the oil return capillary 20a and returns to the compressor 1 together with the refrigerant. The refrigerant condensed in the heat source side heat exchanger 3 is further heat-condensed with the low-pressure gas-liquid two-phase refrigerant in the refrigerant heat exchanger 18 to be condensed into a liquid or low-dryness gas-liquid two-phase refrigerant. This gas-liquid two-phase refrigerant is throttled to an intermediate pressure by the pressure regulating valve 22.

Here, the pressure regulating valve 22 is controlled to be lower than the pressure resistance of the existing liquid pipe 28. The gas-liquid two-phase refrigerant or the liquid single-phase refrigerant having an intermediate pressure flows through the liquid pipe and is throttled to a low pressure by the throttle devices 5a and 5b. If the intermediate pressure should exceed the pressure resistance of the existing liquid pipe 28, the pressure switch 23b is activated and the operation is stopped. In the load-side heat exchangers 6a and 6b, the low-pressure gas-liquid two-phase refrigerant takes heat from the surroundings and cools it, and it evaporates and becomes a liquid two-phase refrigerant having a high dryness and flows through the gas pipe 29. The gas-liquid two-phase refrigerant that has flowed through the gas pipe 29 flows into the refrigerant heat exchanger 18 together with contaminants such as mineral oil, and the refrigerant liquid evaporates and enters the accumulator 8 through the four-way valve 2 together with the liquid contaminants. In the accumulator 8, the refrigerant gas and the contamination are separated, the refrigerant gas returns to the compressor 1, and the contamination stays in the accumulator 8.
Contaminants collected in the accumulator are appropriately discharged after washing from a discharge port (not shown) provided at the bottom of the accumulator 8.

  Next, the operation when the washing operation is performed in the heating cycle in STEP 3 will be described. When the compressor 1 is operated, the high-temperature and high-pressure gas refrigerant is separated from the refrigeration oil taken out from the compressor 1 by the oil separator 9, and the refrigerant gas is condensed and liquefied by the refrigerant heat exchanger 18 through the four-way valve 2. The The refrigerating machine oil separated by the oil separator 9 flows into the suction pipe of the compressor through the oil return capillary 20a and returns to the compressor 1 together with the refrigerant. The liquid refrigerant condensed in the refrigerant heat exchanger 18 becomes a highly dry gas-liquid two-phase refrigerant, flows through the gas pipe 29, and flows to the load-side heat exchangers 6a and 6b.

  Here, the high-pressure gas is controlled to a pressure that does not exceed the pressure resistance of the existing gas pipe 29. In the unlikely event that the pressure resistance of the existing gas pipe 29 is likely to be exceeded, the pressure switch 23c is activated and the operation is stopped. The highly dry refrigerant in the load side heat exchangers 6a and 6b dissipates heat to the surroundings and heats it, and condenses and liquefies itself and is throttled to a low pressure by the expansion devices 5a and 5b. The low-pressure gas-liquid two-phase refrigerant flows through the liquid pipe 28 and flows into the refrigerant heat exchanger 18 along with the contamination, and becomes a gas-liquid two-phase refrigerant with high dryness. This highly dry gas-liquid two-phase refrigerant and contaminants together enter the heat source side heat exchanger 3, the refrigerant gas evaporates and vaporizes, and enters the accumulator 8 through the four-way valve 2. In the accumulator 8, the refrigerant gas and the contamination are separated, the refrigerant gas returns to the compressor 1, and the contamination stays in the accumulator.

  Thus, STEP 3 is operated, and after a predetermined time has elapsed, STEP 3 is terminated and the process proceeds to STEP 4. Here, the predetermined time for operation in STEP 3 is the time until the refrigeration cycle reaches a steady state. For example, in a state where the frequency of the compressor reaches a predetermined frequency and becomes constant, the time change of high pressure or low pressure May be changed to 0.1 MPa. Alternatively, a time until stabilization is obtained in advance, and a fixed time may be used. Furthermore, when the refrigerant amount is extremely deviated from the appropriate amount and it becomes difficult to continue the operation, STEP 3 is ended and the process proceeds to STEP 4.

  In STEP 4, the amount of refrigerant is adjusted. The refrigerant amount is adjusted by adding refrigerant from the refrigerant charging port 30, detecting that the condenser outlet SC and the evaporator outlet SH of the refrigeration cycle have reached predetermined values, ending STEP4 and proceeding to STEP5. . If the refrigerant is not properly charged for a predetermined time or longer, the operation is stopped and an overtime warning is issued to the outside. Here, the appropriate amount of refrigerant is determined to be appropriate if two criteria are provided, that is, the amount of refrigerant necessary for normal air conditioning operation and the amount of refrigerant necessary for continuing the cleaning operation. However, the amount of refrigerant required to continue the cleaning operation is satisfied, but if the amount of refrigerant required for normal air conditioning operation is not satisfied, it is necessary to adjust the amount of refrigerant again after a series of cleaning operations. Report something externally.

  In STEP 5, the cleaning operation is resumed. Although the operation is almost the same as STEP 3, the operation frequency of the compressor may be operated at the maximum capacity in order to end the cleaning operation quickly. This operation is performed for a predetermined time, STEP5 is ended, and the process proceeds to STEP6. Here, as shown in FIG. 4, the predetermined time for operation in STEP5 is, for example, a parameter that affects the high or low pressure of the refrigeration cycle operation such as outdoor air temperature or indoor air temperature, and the flow rate of the cleaning flow increases or decreases. In this way, parameters that affect the amount of residual oil in the pipe and the time required to move the oil are selected, a map is created from the combination of these, and the cleaning time is determined. The pipe length may be determined from the difference between the evaporation temperature detected in the room (sensor not shown) and the evaporation temperature detected by the outdoor unit, the opening of the throttle to be balanced, and the like.

  In STEP 6, the oil accumulated in the accumulator 8 is collected, and when the discharge is completed, STEP 6 is terminated, the process proceeds to STEP 7, and the air conditioning operation is started. The operator confirms whether or not the oil accumulated in the accumulator 8 has been recovered by notifying the heat source unit A with a switch. Further, it may be automatically confirmed that the oil is discharged by detecting the liquid level in the accumulator 8. Further, when oil discharge is not confirmed for a predetermined time or longer, the operation is stopped and an overtime warning is issued to the outside.

  In STEP 7, the normal operation is started after the cleaning operation is performed in the cooling cycle or the heating cycle. At this time, when the oil return solenoid valve 15b is opened, the refrigeration oil in the oil tank 17 flows into the suction pipe of the compressor 1 and returns to the compressor 1 together with the refrigerant gas.

  Next, the operation when the cooling operation is performed in the normal air conditioning operation will be described. When the compressor 1 is operated, the high-temperature and high-pressure gas refrigerant is separated from the refrigerating machine oil taken out from the compressor 1 by the oil separator 9, and the refrigerant gas is condensed and liquefied by the heat source side heat exchanger 3 via the four-way valve 2. Is done. The refrigerating machine oil separated by the oil separator 9 flows into the suction pipe of the compressor 1 through the oil return capillary 20a and returns to the compressor 1 together with the refrigerant. The liquid refrigerant condensed in the heat source side heat exchanger 3 is further condensed by exchanging heat with the low-pressure gas-liquid two-phase refrigerant in the refrigerant heat exchanger 18 to become supercooled liquid refrigerant. This liquid refrigerant is throttled to an intermediate pressure by the pressure regulating valve 22.

  Here, the flow rate adjusting valve 19 is controlled so as to be lower than the pressure resistance of the existing liquid pipe 28 and gas pipe 29, and has a sufficient degree of supercooling so that a gas-liquid two-phase state does not occur even if the pressure is reduced to the intermediate pressure. Try to put it on. The liquid single-phase refrigerant having an intermediate pressure flows through the liquid pipe and is throttled to a low pressure by the throttle devices 5a and 5b. In the unlikely event that the intermediate pressure exceeds the pressure resistance of the existing liquid pipe 28 and gas pipe 29, the pressure switch 23b is activated to stop the operation. In the load-side heat exchangers 6 a and 6 b, the low-pressure gas-liquid two-phase refrigerant takes heat from the surroundings and cools it, and evaporates and gasifies and flows through the gas pipe 29. The gas refrigerant that has flowed through the gas pipe 29 merges with the refrigerant in the gas-liquid two-phase state that is bypassed through the throttle 31, exchanges heat with the high-pressure liquid refrigerant in the refrigerant heat exchanger 18, and is gasified in a four-way state. It returns to the compressor 1 through the valve 2 and the accumulator 8.

  Next, an operation in the case of performing a heating operation in a normal air conditioning operation will be described. When the compressor 1 is operated, the high-temperature and high-pressure gas refrigerant is separated from the refrigeration oil taken out from the compressor 1 by the oil separator 9, and the refrigerant gas is condensed and liquefied by the refrigerant heat exchanger 18 through the four-way valve 2. The The refrigerating machine oil separated by the oil separator 9 flows into the suction pipe of the compressor through the oil return capillary 20a and returns to the compressor 1 together with the refrigerant. The high-temperature and high-pressure gas refrigerant from which the oil has been separated flows through the gas pipe 29 and flows to the load-side heat exchangers 6a and 6b. Here, the high-pressure gas is controlled to a pressure that does not exceed the pressure resistance of the existing gas pipe 29. In the unlikely event that the pressure resistance of the existing gas pipe 29 is likely to be exceeded, the pressure switch 23c is activated and the operation is stopped. The highly dry refrigerant in the load side heat exchangers 6a and 6b dissipates heat to the surroundings and heats it, and condenses and liquefies itself and is throttled to a low pressure by the expansion devices 5a and 5b. The low-pressure gas-liquid two-phase refrigerant flows through the liquid pipe 28, enters the heat source side heat exchanger 3, the refrigerant gas evaporates and vaporizes, and returns to the compressor 1 through the four-way valve 2 and the accumulator 8.

As described above, at the start of the air-conditioning operation, the gas-liquid that flows into the existing liquid pipe 28 and gas pipe 29 to enable the cleaning operation and condenses in the load-side heat exchangers 6a and 6b to enable the heating operation. Since the refrigerant heat exchanger 18 for generating the two-phase refrigerant is provided, the load-side heat exchangers 6a and 6b can perform the heating operation even in the cleaning operation.
Therefore, air-conditioning operation can be started immediately after the construction, and a comfortable indoor environment can be provided, and by collecting the contaminants, there is an effect of reducing damage due to residual foreign matter and improving reliability.

  In addition, even when replacing with refrigerants having different operating pressures such as R22 and R410A or R407C to R410A, the operation can be controlled so as not to exceed the pressure resistance of the existing liquid pipe 28 and gas pipe 29, which is safe. . Here, in the case of updating from R407C to R410A, a switch that omits cleaning may be provided.

In addition, since the oil tank 17 that fills the refrigerant circuit with oil after the predetermined washing operation is performed, a sufficient amount of refrigerating machine oil in the compressor 1 can be ensured even after washing, There is no occurrence of oil depletion and the reliability can be increased.
Moreover, the trouble of filling from the outside after washing can be saved.

  In addition, as shown in FIG. 5, you may provide the solenoid valve 14a which bypasses the refrigerant | coolant heat exchanger 18 in a gas pipe. Further, a strainer may be provided between the lower part of the accumulator 8 and the flow rate adjustment valve 19 to prevent foreign matter from clogging the flow rate adjustment valve. Furthermore, a foreign matter catcher 309 is installed between the four-way valve 2 and the accumulator 8 to catch solid foreign matters and liquid foreign matters such as mineral oil during cleaning, and by bypassing the foreign matter catcher in normal operation, it is more reliable. In addition, the operation of draining oil after cleaning can be made unnecessary, and the cleaning time and the time for updating the heat source side unit A and the load side unit B can be shortened.

Embodiment 2. FIG.
FIG. 6 is a refrigerant circuit diagram of a refrigerating and air-conditioning apparatus showing Embodiment 2 of the present invention. In FIG. 6, the same parts as those of FIG. In FIG. 1 which is the refrigerant circuit of the first embodiment, the refrigerant heat exchanger 18 is installed at a position where heat exchange is performed between the liquid pipe and the gas pipe. In FIG. 6 which is a refrigerant circuit diagram of the second embodiment, the liquid pipe The liquid piping is bypassed and heat exchange with the low-pressure piping through the throttle 31 is performed. Further, two oil tanks 17a and 17b are installed, and the upper portions of the oil tanks 17a and 17b are connected to each other by a refrigerant pipe, and the lower portions of the compressor 1 are respectively connected via an oil return solenoid valve 15b and an oil return solenoid valve 15c. Connect to the suction pipe.

  In this configuration, since the flow from the construction of the unit at the site to the start of the air conditioning operation is the same as in FIG. 2, the entire description is omitted, and the cleaning operation is performed in STEP 3 and STEP 5 in the flow of FIG. The operation will be described. First, when cleaning is performed in the cooling cycle, when the compressor 1 is operated, the high-temperature and high-pressure gas refrigerant is separated from the refrigerating machine oil taken out from the compressor 1 by the oil separator 9. Here, a large amount of oil is put in the compressor 1 in advance so that the amount of oil taken out without being separated by the oil separator 9 is increased. In this way, the amount of oil in the compressor 1 and the amount of oil taken out generally have a correlation as shown in FIG. 7, so that the amount of oil taken out from the compressor 1 increases and the oil separator 9 The amount of ester oil that is not separated also increases. In addition, the oil return solenoid valve 15b below the oil tank 17a is opened for a predetermined time so that the amount of oil in the compressor 1 continues to increase, and the oil in the oil tank 17a is filled into the compressor 1. .

  The refrigerant gas containing the ester oil is condensed and liquefied by the refrigerant heat exchanger 18 via the four-way valve 2. The refrigerating machine oil separated by the oil separator 9 flows into the suction pipe of the compressor 1 through the oil return capillary 20a and returns to the compressor 1 together with the refrigerant. The refrigerant condensed in the heat source side heat exchanger 3 is bypassed from itself in the refrigerant heat exchanger 18 and becomes a liquid refrigerant which is supercooled by heat exchange with the gas-liquid two-phase refrigerant whose pressure is reduced by the throttle 31. This liquid refrigerant is throttled to an intermediate pressure by the flow rate adjusting valve 19. Here, the flow rate adjusting valve 19 is controlled to be lower than the pressure resistance of the existing liquid pipe 28 and gas pipe 29. The gas-liquid two-phase refrigerant or the liquid single-phase refrigerant having an intermediate pressure flows through the liquid pipe and is throttled to a low pressure by the throttle devices 5a and 5b.

  If the intermediate pressure should exceed the pressure resistance of the existing liquid pipe 28, the pressure switch 23b is activated and the operation is stopped. In the load-side heat exchangers 6a and 6b, the low-pressure gas-liquid two-phase refrigerant takes heat from the surroundings and cools it, and evaporates to become a gas refrigerant containing ester oil and flows through the gas pipe 29. The gas refrigerant that has flowed through the gas pipe 29 enters the accumulator 8 through the four-way valve 2 together with contamination in which ester oil and mineral oil are mixed. In the accumulator 8, the refrigerant gas and the contamination are separated, the refrigerant gas returns to the compressor 1, and the contamination stays in the accumulator. Here, in the gas pipe 29, the ester oil and the mineral oil are mixed, so that the refrigerant is dissolved in the mixed liquid of the mineral oil and the ester oil, and the movement of the mineral oil in the existing gas pipe 29 is promoted. The recovery of mineral oil in the gas pipe 29 is completed quickly.

  When washing is performed in the heating cycle, when the compressor 1 is operated, the high-temperature and high-pressure gas refrigerant is separated from the refrigerating machine oil taken out of the compressor 1 by the oil separator 9. Here, a large amount of oil is put in the compressor 1 in advance so that the amount of oil taken out without being separated by the oil separator 9 is increased. In this way, the amount of oil in the compressor 1 and the amount of oil taken out generally have a correlation as shown in FIG. 7, so that the amount of oil taken out from the compressor 1 increases and the oil separator 9 The amount of ester oil that is not separated also increases. In addition, the oil return solenoid valve 15b below the oil tank 17a is opened for a predetermined time so that the amount of oil in the compressor 1 continues to increase, and the oil in the oil tank 17a is filled into the compressor 1. .

  The refrigerant gas containing the ester oil is condensed and liquefied by the refrigerant heat exchanger 18 via the four-way valve 2. The refrigerating machine oil separated by the oil separator 9 flows into the suction pipe of the compressor through the oil return capillary 20a and returns to the compressor 1 together with the refrigerant. A high-temperature, high-pressure gas refrigerant containing ester oil flows through the gas pipe 29 to the load side heat exchangers 6a and 6b, mixes with the mineral oil remaining in the existing gas pipe 29, and forms a mixed liquid of ester oil and mineral oil. The refrigerant dissolves and becomes a low-viscosity liquid and flows through the existing gas pipe 29. Here, the high-pressure gas is controlled to a pressure that does not exceed the pressure resistance of the existing gas pipe 29.

  In the unlikely event that the pressure resistance of the existing gas pipe 29 is likely to be exceeded, the pressure switch 23c is activated and the operation is stopped. The highly dry refrigerant in the load side heat exchangers 6a and 6b dissipates heat to the surroundings and heats it, and condenses and liquefies itself and is throttled to a low pressure by the expansion devices 5a and 5b. The low-pressure gas-liquid two-phase refrigerant flows through the liquid pipe 28 and flows into the refrigerant heat exchanger 18 along with the contamination, and becomes a gas-liquid two-phase refrigerant with high dryness. This highly dry gas-liquid two-phase refrigerant and contaminants together enter the heat source side heat exchanger 3, the refrigerant gas evaporates and vaporizes, and enters the accumulator 8 through the four-way valve 2. In the accumulator 8, the refrigerant gas and the contamination are separated, the refrigerant gas returns to the compressor 1, and the contamination stays in the accumulator.

  After carrying out in the above washing operation STEP5, after discharging the oil in STEP6, air conditioning operation STEP7 is started. Here, at the start of STEP 7, the oil return solenoid valve 15c at the lower part of the oil tank 17b is opened, the oil in the oil tank 17b is filled into the compressor 1, and the oil amount in the compressor 1 that has decreased during the cleaning is normalized. Return to the amount. At the start of the air-conditioning operation, the refrigerant is flowed by the same operation as during cleaning, and the air-conditioning operation is performed.

As described above, at the start of the air-conditioning operation, the gas-liquid that flows into the existing liquid pipe 28 and gas pipe 29 to enable the cleaning operation and condenses in the load-side heat exchangers 6a and 6b to enable the heating operation. Since the refrigerant heat exchanger 18 that generates the two-phase refrigerant is provided, the refrigerant operation during the cleaning operation and the normal air-conditioning operation is the same, and with a simple configuration, it is equivalent to the normal air-conditioning operation during the cleaning. Can demonstrate their abilities.
In addition, since the oil tanks 17a and 17b for filling the refrigerant circuit with oil after the predetermined washing operation is carried out, it is possible to ensure a sufficient amount of the refrigerating machine oil in the compressor 1 even after washing. it can.
In addition, by adding a large amount of oil from the oil tank 17a to the compressor 1 in advance so that the amount of oil taken out from the oil separator 9 is increased, the ester oil is supplied to the load side heat exchangers 6a and 6b. Since it becomes a gas refrigerant containing and flows through the gas pipe 29, the ester oil and the mineral oil are mixed, and the refrigerant is dissolved in the mixed liquid of the mineral oil and the ester oil, and the movement of the mineral oil in the existing gas pipe 29 is promoted. The mineral oil recovery in the existing gas pipe 29 can be completed quickly.

It is a refrigerant circuit figure of the refrigerating air-conditioning apparatus of Embodiment 1 of this invention. It is a figure which shows the work flow of Embodiment 1 of this invention. It is a figure which shows the map which determines the operation mode of Embodiment 1 of this invention. It is a figure which shows the map which determines the washing | cleaning driving | running time of Embodiment 1 of this invention. It is another refrigerant circuit figure of the refrigerating air-conditioning apparatus of Embodiment 1 of this invention. It is a refrigerant circuit figure of the refrigerating air-conditioning apparatus of Embodiment 2 of this invention. It is a figure which shows the relationship between the oil quantity in the compressor of Embodiment 2 of this invention, and the amount of taking-out of oil.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Compressor, 2 way valve, 3 Heat source side heat exchanger, 6a, 6b Load side heat exchanger, 8 Accumulator, 17, 17a, 17b Oil tank, 18 Refrigerant heat exchanger, 28 liquid piping, 29 Gas piping.

Claims (5)

In a refrigeration air conditioner in which a new heat source side unit and a load side unit are connected by an existing refrigerant pipe,
The new heat source side unit is equipped with at least a compressor, a heat source side heat exchanger, a refrigerant heat exchanger, and an accumulator,
The new load side unit is equipped with at least throttling means and a load side heat exchanger,
The refrigerant heat exchanger is provided at a position where heat can be exchanged between the refrigerant between the heat source side heat exchanger and the throttling means and the refrigerant between the load side heat exchanger and the accumulator. And
The refrigerant heat exchanger generates a gas-liquid two-phase refrigerant capable of air-conditioning operation while performing a cleaning operation in which the refrigerant flows through the existing refrigerant pipe and collects foreign matter in the accumulator. Refrigeration air conditioner. During heating operation,
In the refrigerant heat exchanger,
The refrigerating and air-conditioning apparatus according to claim 1, wherein the refrigerant discharged from the compressor is heat-exchanged with a low-pressure gas-liquid two-phase refrigerant to condense to obtain a gas-liquid two-phase refrigerant having a high dryness . During cooling operation,
In the refrigerant heat exchanger,
2. The refrigeration according to claim 1, wherein the refrigerant condensed in the heat source side heat exchanger is subjected to heat exchange with a low-pressure gas-liquid two-phase refrigerant and further condensed to form a gas-liquid two-phase refrigerant having a low dryness. Air conditioner. An oil separator that separates oil and refrigerant; and an oil tank that stores oil separated by the oil separator;
The refrigerating and air-conditioning apparatus according to any one of claims 1 to 3 , wherein oil stored in the oil tank is filled in the refrigerant circuit after the cleaning operation is performed . The refrigerating and air-conditioning apparatus according to claim 4, comprising a plurality of the oil tanks .

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