JP2007163084A - Supercooling device and air conditioning system with supercooling device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently operate a supercooling device for supercooling refrigerant. <P>SOLUTION: The supercooling device 21 is mounted on an outdoor unit 2 of the air conditioning system 1. This device comprises an ejector 22 using gas refrigerant separated by a gas-liquid separator 18 connected to an outdoor heat exchanger 14 as a driving flow; and a supercooler 23 for distributing low-temperature, low-pressure refrigerant that forms a sucking flow of the ejector 22 into an inner tube 31, and a pressure reducing device 24 for forming the low-temperature, low-pressure refrigerant to be distributed to the inner tube 31. Liquid refrigerant is distributed in an outer tube 34 of the supercooler 23, and this liquid refrigerant is supercooled by heat exchange with the refrigerant in the inner tube 31 and supplied to an indoor unit 3. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a supercooling device that supercools a high-temperature refrigerant and an air conditioner including the supercooling device.

  An example of an apparatus that circulates the refrigerant discharged from the compressor while performing heat exchange and performs a cooling operation is an air conditioner. Some conventional air conditioners use an ejector as a pressure reducing device (see, for example, Patent Document 1). A refrigerant from the condenser is used for the drive flow of the ejector, and a refrigerant flowing out of the evaporator is used for the suction flow. The refrigerant flowing out from the ejector is guided to the gas-liquid separator. The gas-liquid separator separates the refrigerant flowing from the ejector into a saturated gas refrigerant and a saturated liquid refrigerant, supplies the saturated gas refrigerant to the compressor, and supplies the saturated liquid refrigerant to the evaporator. During the cooling operation, the refrigerant is decompressed and expanded by the ejector, and the expansion energy at that time is converted into pressure energy, whereby the suction pressure of the compressor can be increased.

Some air conditioners have a double-tube supercooling device (see, for example, Patent Document 2). In the supercooling device, a pipe through which the liquid refrigerant flowing out from the outdoor heat exchanger during cooling operation passes is connected to the inner pipe, and a suction pipe of the compressor is connected to the outer pipe. The low-temperature and low-pressure refrigerant passing through the outer pipe exchanges heat with the high-temperature and high-pressure liquid refrigerant passing through the inner pipe. The liquid refrigerant can be supplied to the condenser after being supercooled.
JP 2003-262413 A JP 2003-279170 A

However, in the configuration including the ejector, the gas-liquid two-phase refrigerant flowing out of the condenser is used as the driving flow. However, when the two-phase refrigerant is used for the driving flow, energy recovery is achieved compared to the case of the single-phase flow. The rate drops. In particular, when a CO ₂ refrigerant is used, energy is easily recovered even with a two-phase refrigerant, but when an HFC refrigerant such as R410A is used, the energy recovery rate is reduced. In addition, although the saturated liquid refrigerant of the gas-liquid separator flows into the evaporator, the saturated liquid refrigerant cannot easily be overcooled, and thus easily becomes a two-phase refrigerant. In a configuration in which a plurality of evaporators are connected in parallel as in the multi-system, a pipe for passing the saturated liquid refrigerant from the gas-liquid separator becomes long, so that part of the liquid refrigerant evaporates before reaching the evaporator. It was easy. For this reason, it has become easy to produce an evaporator with sufficient capacity and an evaporator with insufficient capacity.

In the configuration including the supercooling device, the temperature of the refrigerant sucked into the compressor through the supercooling device may become too high. If the gas refrigerant that has been overheated in this way is directly sucked into the compressor, the capacity of the compressor will be reduced.
The present invention has been made in view of such circumstances, and its main object is to efficiently perform heat exchange in a supercooling device that supercools a refrigerant.

  The present invention that solves the above-described problems is a supercooling device that supercools a high-temperature and high-pressure liquid refrigerant when circulating the refrigerant compressed by the compressor, and uses the high-pressure refrigerant bypassing the indoor unit as a driving flow, and the compression An ejector that causes the refrigerant to be sucked into the machine to flow out, a supercooler that uses the suction flow of the ejector as a cooling heat source, supercools the high-temperature and high-pressure liquid refrigerant that flows into the indoor unit during cooling operation by heat exchange, and the cooling heat source And a decompression device that forms a refrigerant having a lower temperature and lower pressure than the gas refrigerant to be sucked into the compressor.

  In this supercooling device, the low-temperature and low-pressure refrigerant used in the suction flow of the ejector is lower-pressure (low-temperature) refrigerant than the suction pressure of the compressor in the decompression device. This low-temperature and low-pressure refrigerant is used as a low-temperature heat source in the supercooler to supercool the high-temperature and high-pressure liquid refrigerant. The low-temperature and low-pressure refrigerant is used for heat exchange as a low-temperature heat source, and then sucked into the ejector and pressurized, and then sucked into the compressor.

  According to the present invention, since the low-temperature and low-pressure refrigerant used as the suction flow of the ejector is used as a low-temperature heat source for exchanging heat with the subcooler, the temperature of the low-temperature heat source used for the subcooler is lowered than before. It becomes possible to use in the state. The temperature difference between the high-temperature heat source and the low-temperature heat source can be increased, the heat exchange efficiency in the supercooler is improved, and the liquid refrigerant can be reliably supercooled. Further, since a refrigerant having a lower temperature than that of the conventional one is used as a low-temperature heat source, the temperature of the refrigerant after heat exchange does not become too high, and a reduction in the capacity of the compressor can be prevented.

A first embodiment for carrying out the invention will be described in detail with reference to the drawings.
FIG. 1 shows the configuration of an air conditioner as an example of a device equipped with a supercooler. The air conditioner 1 is a multi-system in which a plurality of indoor units 3 are connected in parallel to one outdoor unit 2.

  The outdoor unit 2 includes a compressor 10 that compresses a refrigerant, and a discharge pipe 11 connected to a discharge port of the compressor 10 is connected to a first port 12A of a four-way valve 12. In the four-way valve 12, when the first port 12A and the second port 12B are connected, the third port 12C and the fourth port 12D are connected, and the first port 12A and the third port 12C are connected. The second port 12B and the fourth port 12D are sometimes connected. The second port 12B is connected to one inflow / outlet of the outdoor heat exchanger 14 via the pipe 13. A pipe 15 is connected to the other inlet / outlet of the outdoor heat exchanger 14, and the pipe 15 has an expansion valve 16 and a check valve 17 that bypasses the expansion valve 16 provided in parallel in the path. The gas-liquid separator 18 is connected. The gas-liquid separator 18 is connected to a gas pipe 19 through which the saturated gas refrigerant flows out and a liquid pipe 20 through which the saturated liquid refrigerant flows in / out. These pipes 19 and 20 are connected to a supercooling device 21.

  The supercooling device 21 includes an ejector 22 that takes in a saturated gas refrigerant as a driving flow, a supercooler 23 that is connected to the ejector 22 so as to supply a suction flow of the ejector 22, and a refrigerant that is supplied to the subcooler 23. And a decompression device 24 for decompressing. The ejector 22 is gradually ejected from the nozzle unit 22A that ejects while reducing the driving flow, the mixing unit 22B that sucks and mixes the refrigerant from the supercooler 23 by ejecting the gas refrigerant from the nozzle unit 22A, and the mixing unit 22B. And a diffuser portion 22C having an increased diameter, and the refrigerant is boosted by the mixing portion 22B and the diffuser portion 22C. A suction pipe 26 is connected to the diffuser portion 22C, and the suction pipe 26 is connected to the accumulator 28 after the suction pipe 27 connected to the fourth port 12D of the four-way valve 12 joins. From the accumulator 28, saturated gas refrigerant is sucked into the compressor 10 through the suction pipe 29.

  Here, the suction pipe 27 extending from the four-way valve 12 is branched from the pipe 30 in the middle thereof. The pipe 30 is connected to the first end portion 31 </ b> A of the inner pipe 31 of the subcooler 23 after a decompression device 24 such as a capillary tube is provided in the middle. The subcooler 23 has a double pipe structure, and a pipe 32 extending from the second end 31B of the inner pipe 31 is connected to a suction port 33 formed in the mixing part 22B of the ejector 22. A liquid pipe 20 extending from the gas-liquid separator 18 is connected to the second end 34 </ b> B of the outer tube 34. A liquid pipe 35 is connected to the first end 34 </ b> A of the outer pipe 34. The liquid pipe 35 is branched into a plurality of parts after extending outside the outdoor unit 2, and is drawn into each indoor unit 3.

  The indoor unit 3 is connected to one inflow / outlet of the indoor heat exchanger 41 after the liquid pipe 35 passes through the expansion valve 40. A gas pipe 42 is connected to the other inlet / outlet of the indoor heat exchanger 41. The gas pipe 42 is connected to the third port 12 </ b> C of the four-way valve 12 of the outdoor unit 2 after being drawn out from the indoor units 3 and joined. The gas pipe 42 and the liquid pipe 35 are provided with open / close valves 43 and 44 in the pipe line so that the gas pipe 42 and the liquid pipe 35 can be separated from each other inside and outside the outdoor unit 2.

Next, the operation of this embodiment will be described.
When the air conditioner 1 performs a cooling operation, the first port 12A and the second port 12B of the four-way valve 12 are connected, and the third port 12C and the fourth port 12D are connected. The high-temperature and high-pressure gas refrigerant discharged from the compressor 10 flows from the discharge pipe 11 through the four-way valve 12 into the outdoor heat exchanger 14. The outdoor heat exchanger 14 functions as a condenser, and the refrigerant passing through the outdoor heat exchanger 14 exchanges heat with the outside air. The refrigerant after heat exchange flows out of the outdoor heat exchanger 14 and flows into the gas-liquid separator 18. From the gas-liquid separator 18, a saturated high-temperature and high-pressure gas refrigerant is supplied from the gas pipe 19 to the supercooling device 21. Further, a high-temperature liquid refrigerant in a saturated state is supplied from the liquid pipe 20 to the supercooling device 21.

  The high-temperature and high-pressure gas refrigerant flowing out from the gas-liquid separator 18 to the gas pipe 19 flows into the nozzle portion 22A of the ejector 22 and is ejected as a single-phase driving flow. On the other hand, the high-temperature and high-pressure liquid refrigerant flowing out from the gas-liquid separator 18 into the liquid pipe 20 flows into the outer tube 34 of the supercooler 23 from the second end 34B and out of the first end 34A. At this time, heat is exchanged with a low-temperature and low-pressure gas refrigerant passing through the inner pipe 31 to perform supercooling. The supercooled liquid refrigerant is guided to the indoor unit 3 through the liquid pipe 35. In the indoor unit 3, the indoor heat exchanger 41 functions as an evaporator, the liquid refrigerant evaporates by heat exchange, and cools the air by taking the heat of vaporization from the air. The room is cooled by the cooled air. The gas refrigerant formed by heat exchange is returned from the gas pipe 42 to the outdoor unit 2. The refrigerant flows into the suction pipe 27 through the four-way valve 12, a part of the gas refrigerant is guided to the accumulator 28, and the remaining gas refrigerant is supplied to the supercooler 23 of the supercooling device 21 through the pipe 30.

  The gas refrigerant supplied through the pipe 30 passes through the decompression device 24 before being supplied to the subcooler 23, so that the gas pressure at the time of evaporation in the outdoor unit 2 and the suction pressure of the compressor 10 are exceeded. It becomes a low-pressure and low-temperature gas refrigerant. This low-temperature and low-pressure gas refrigerant flows into the subcooler 23 from the first end 31A of the inner pipe 31 as a low-temperature heat source. The supercooler 23 is heated by exchanging heat with the high-temperature and high-pressure liquid refrigerant flowing through the outer tube 34 as described above. Since the temperature of the low-temperature and low-pressure gas refrigerant is originally low, the temperature of the gas refrigerant after heat exchange does not become too high. The gas refrigerant is sucked into the ejector 22 when it flows out of the subcooler 23 from the second end 31B.

  In the ejector 22, it is attracted | sucked by the attraction | suction force which the drive flow which consists of a single phase of the gas refrigerant supplied from the gas piping 19 forms. The low-temperature and low-pressure gas refrigerant is mixed with the driving flow in the mixing unit 22B, and after being pressurized, flows into the accumulator 28. From the accumulator 28, the refrigerant is sucked into the compressor 10 through the suction pipe 29. The gas refrigerant sucked into the compressor 10 is compressed again and discharged.

  According to this embodiment, since the low-temperature and low-pressure refrigerant sucked and pressurized by the ejector 22 is configured as the low-temperature heat source of the supercooler 23, a low-temperature and low-pressure gas refrigerant is used as the low-temperature heat source. Is possible. For this reason, since a temperature difference with a high-temperature / high pressure liquid refrigerant can be enlarged, the heat exchange efficiency in the supercooler 23 can be improved. Therefore, the degree of supercooling of the liquid refrigerant supplied to the indoor unit 3 can be increased, and the variation in capacity between the indoor units 3 can be prevented. Here, since the temperature of the low-temperature and low-pressure gas refrigerant used in the supercooler 23 is lower than that of the conventional one, the temperature does not become too high even if heat exchange is performed with the high-temperature and high-pressure liquid refrigerant. Therefore, even if such a gas refrigerant is sucked into the compressor 10, the reliability of the compressor 10 is not impaired.

The two-phase refrigerant formed through the outdoor heat exchanger 14 is guided to the gas-liquid separator 18 and separated into the saturated gas refrigerant and the saturated liquid refrigerant by the gas-liquid separator 18, and the saturated gas refrigerant is used to drive the ejector 22. Since the indoor unit 3 is bypassed and collected in the compressor 10 while being used as a flow, gas components that do not substantially contribute to cooling do not flow to the indoor unit 3. Therefore, the liquid refrigerant can be efficiently evaporated in the indoor unit 3. The cooling operation of the air conditioner 1 is highly efficient, and the air conditioner 1 can be downsized accordingly.
Since a high-pressure saturated gas refrigerant composed of a single phase is used for the drive flow of the ejector 22, energy recovery efficiency can be improved as compared with a conventional configuration using a two-phase refrigerant as a drive flow. For this reason, the air conditioning apparatus 1 can be reduced in size.

  In addition, the air conditioning apparatus 1 can perform heating operation similarly to a known air conditioning apparatus by switching the four-way valve 12.

A second embodiment of the present invention will be described in detail with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same component as 1st Embodiment. In addition, redundant description is omitted.
As shown in FIG. 2, the air conditioner 51 is different from the first embodiment only in the configuration of the outdoor unit 52. The outdoor unit 52 is connected to the compressor 10, the four-way valve 12, and the outdoor heat exchanger 14, and the pipe 15 connected to the other inlet / outlet of the outdoor heat exchanger 14 includes an expansion valve 16 and a check valve. 17 is connected to the supercooling device 53.

  The supercooling device 53 includes the ejector 22, the supercooler 23, and the decompression device 24. A pipe 60 branched from a pipe 15 extending from the outdoor heat exchanger 14 is connected to the nozzle portion 22A of the ejector 22. The on-off valve 61 provided in the pipe 60 is not necessarily provided. The suction pipe 62 extending from the diffuser portion 22C of the ejector 22 is connected to the accumulator 28 that is a gas-liquid separator after joining the suction pipe 27. The accumulator 54 is configured such that a saturated gas component is sucked into the compressor 10 through the suction pipe 29. The saturated liquid refrigerant flows out from the pipe 63. The pipe 63 is provided with a decompression device 24 such as a capillary tube in the middle, and forms a low-temperature and low-pressure two-phase refrigerant from a saturated liquid refrigerant. Further, the pipe 63 is connected to the first end 31 </ b> A of the inner pipe 31 of the subcooler 23. The second end portion 31 </ b> B of the inner pipe 31 is connected to the suction port 33 of the ejector 22 by a pipe 32. A liquid pipe 35 is connected to the first end 34A of the outer pipe 34 of the subcooler 23, and a pipe 64 branched from the pipe 15 extending from the outdoor heat exchanger 14 is connected to the second end 34B. It is connected.

The operation of this embodiment will be described.
The high-pressure gas refrigerant discharged from the compressor 10 during the cooling operation is condensed in the outdoor heat exchanger 14 and becomes a high-temperature and high-pressure liquid refrigerant. The high-temperature and high-pressure liquid refrigerant is supplied from the pipe 60 to the nozzle portion 22A of the ejector 22 and becomes a driving flow. On the other hand, the high-temperature and high-pressure liquid refrigerant led to the outer pipe 34 of the supercooler 23 is supercooled by exchanging heat with the low-temperature and low-pressure two-phase refrigerant flowing through the inner pipe 31, and is transferred from the liquid pipe 35 to each indoor unit 3. Led. Note that the low-temperature and low-pressure two-phase refrigerant flowing through the inner pipe 31 of the supercooler 23 is obtained by decompressing the saturated liquid refrigerant flowing out of the accumulator 54 by the decompression device 24. The pressure of the two-phase refrigerant is lower than the gas pressure when the liquid refrigerant evaporates in the indoor unit 3 and the suction pressure of the compressor 10. The low-temperature and low-pressure refrigerant (mainly saturated gas refrigerant) formed by heat exchange in the inner pipe 31 of the subcooler 23 becomes the suction flow of the ejector 22 and is joined and pressurized with the high-temperature and high-pressure gas refrigerant. Later, it is returned to the accumulator 54 again. From the accumulator 54, only the saturated gas refrigerant is sucked into the compressor 10. Note that the open / close valve 61 may be closed when the liquid refrigerant supplied to the indoor unit 3 is sufficiently subcooled, such as when the outside air temperature is low.

According to this embodiment, by using the low-temperature and low-pressure refrigerant sucked by the ejector 22 as the low-temperature heat source of the supercooler 23, the refrigerant having a temperature lower than the temperature of the gas refrigerant evaporated in the indoor unit 3 is used. It becomes possible to do. Therefore, the efficiency of heat exchange in the subcooler 23 is improved, and the liquid refrigerant supplied to the indoor unit 3 can be reliably supercooled. In particular, since the liquid refrigerant is supercooled using a low-temperature and low-pressure two-phase refrigerant, the latent heat of the two-phase refrigerant can be used, and the liquid refrigerant can be reliably subcooled.
Since the low-temperature and low-pressure refrigerant after heat exchange in the subcooler 23 is configured to be mixed with the liquid refrigerant that becomes the driving flow in the ejector 22, the two-phase refrigerant flows into the accumulator 54. The gas refrigerant sucked by the compressor 10 from the accumulator 54 becomes a saturated gas obtained from the two-phase refrigerant. Since the low-temperature refrigerant that has passed through the supercooler 23 is included, saturated gas refrigerant having a temperature lower than that of the conventional refrigerant is sucked into the compressor 10, so that it is possible to prevent deterioration in the performance of the compressor 10 due to overheating of the gas refrigerant.

The present invention can be widely applied without being limited to the above-described embodiments.
For example, in the second embodiment, the decompression device 24 is used as an expansion valve, and the opening degree of the expansion valve is controlled based on the temperature on the second end portion 31B side of the inner pipe 31 of the subcooler 23. Then, saturated gas can be reliably formed in the inner pipe 31 by heat exchange of the subcooler 23.
The device including the supercooling devices 21 and 53 is not limited to the air conditioning devices 1 and 51. Any device that circulates and cools the refrigerant in the compressor 10 may be used.
The supercooling devices 21 and 53 may include a gas-liquid separator 18 and an accumulator 54.

It is a figure showing a schematic structure of an air harmony device provided with a supercooling device concerning an embodiment of the invention. It is a figure which shows schematic structure of an air conditioning apparatus provided with the supercooling apparatus which concerns on another form.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,51 Air conditioning apparatus 2 Outdoor unit 3 Indoor unit 10 Compressor 18 Gas-liquid separator 21, 53 Supercooling device 22 Ejector 23 Supercooler 24 Decompression device 54 Accumulator (gas-liquid separator)
63 Piping

Claims (4)

In the supercooling device that supercools the high-temperature and high-pressure liquid refrigerant when circulating the refrigerant compressed by the compressor,
An ejector configured to drive a high-pressure refrigerant bypassing the indoor unit as a driving flow, and to discharge the refrigerant sucked into the compressor;
A supercooler that uses the suction flow of the ejector as a low-temperature heat source and supercools the high-temperature and high-pressure liquid refrigerant that flows into the indoor unit during cooling operation by heat exchange;
A decompression device that forms a refrigerant having a lower temperature and lower pressure than a gas refrigerant to be sucked into the compressor as a cooling heat source;
A supercooling device comprising:   The saturated liquid refrigerant separated by the gas-liquid separator is used as the liquid refrigerant to be supercooled, and the saturated liquid refrigerant separated by the gas-liquid separator is used as the driving flow of the ejector. 2. The supercooling device according to 1.   The gas-liquid separator into which the low-temperature gas refrigerant sucked into the compressor flows in, and the pressure reducing device is provided in a pipe connected to an outlet through which the saturated liquid refrigerant flows out from the gas-liquid separator. The supercooling device according to claim 1. An air conditioner comprising the supercooling device according to any one of claims 1 to 3 in an outdoor unit, and configured to supply a supercooled liquid refrigerant to the indoor unit during cooling operation. .

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