JP2007303709A - Refrigerating cycle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a refrigerating cycle capable of reducing the number of components of a vapor compression type refrigerating cycle, reducing cost and the size of the cycle as a whole, and reducing its weight. <P>SOLUTION: In this refrigerating cycle having an evaporator, a compressor, a radiator for cooling a refrigerant discharged from the compressor, an expander for decompressing and expanding the refrigerant cooled by the radiator, and a gas-liquid separator for separating the refrigerant flowing out of the expander and the refrigerant flowing in from the evaporator into a liquid-phase refrigerant and a gas-phase refrigerant, allowing the liquid-phase refrigerant to flow out to an evaporator side and allowing the gas-phase refrigerant to flow out to a compressor side, a pump means is disposed between the gas-liquid separator and the evaporator for pressure feeding the liquid-phase refrigerant flowing out of the gas-liquid separator to the evaporator side, and the gas-liquid separator and at least the pump means are integrated. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a vapor compression refrigeration cycle, and particularly to a refrigeration cycle suitable for application to a cycle using a refrigerant that is also used in a supercritical region such as a natural refrigerant.

  In the vapor compression refrigeration cycle, the compressed refrigerant is generally cooled by a radiator, the compressed refrigerant is decompressed, and the refrigerant at a low pressure is evaporated by an evaporator to obtain a refrigeration capacity. There is (for example, Patent Document 1).

  In the above-described vapor compression refrigeration cycle, compared with a refrigeration cycle using a conventional chlorofluorocarbon refrigerant, a refrigeration cycle including a supercritical region, for example, a refrigeration cycle using a natural refrigerant such as carbon dioxide, There is a problem that the efficiency of the refrigeration cycle is low because the high-pressure side pressure needs to be increased to the critical pressure of the refrigerant or more, and the required power of the compressor increases.

  In a refrigeration cycle using a conventional chlorofluorocarbon refrigerant, it is desirable to control the degree of superheat of the evaporator outlet refrigerant to 5 to 10 deg in order to efficiently exhibit the performance of the refrigerant evaporator. Therefore, the amount of refrigerant in the evaporator is adjusted so that the dryness of the refrigerant becomes 1 before the outlet of the evaporator. However, in the case of a refrigeration cycle including a supercritical region such as a refrigeration cycle using carbon dioxide as a refrigerant, if the dryness of the refrigerant in the evaporator is increased as usual due to the difference in refrigerant physical properties, the heat transfer coefficient of the evaporator is increased. It greatly decreases, the cooling performance deteriorates, and the efficiency of the refrigeration cycle also deteriorates. Under such circumstances, researches on refrigeration cycles including supercritical regions and their components are actively conducted, and the relationship between the dryness and the heat transfer coefficient is being grasped as well as the characteristics of the evaporator.

A conventional refrigeration cycle 101 is configured, for example, as shown in FIG. 5, and includes a compressor 102 that compresses refrigerant, a radiator 103 that cools refrigerant that has flowed out of the compressor 102, and a high pressure that flows out of the radiator 103. An internal heat exchanger 105 that performs heat exchange between the low-pressure refrigerant that has flowed out of the refrigerant and the accumulator 104 (also serving as a gas-liquid separator) and supplies the low-pressure refrigerant heat-exchanged with the high-pressure refrigerant to the compressor 102; A decompressor 106 that depressurizes the high-pressure refrigerant that has flowed out of the internal heat exchanger 105, an evaporator 107 that evaporates the low-pressure refrigerant that has flowed out of the decompressor 106, and a two-phase liquid-phase refrigerant and gas-phase refrigerant that have flowed out of the evaporator 107 What is known is provided with an accumulator 104 that stores refrigerant and supplies gas-phase refrigerant to the internal heat exchanger 105.
JP 11-193967 A

  In contrast to the above-described conventional technology, the applicant of the present invention uses the expansion energy generated when the high-pressure refrigerant is depressurized for refrigerating cycle operation while regenerating, substantially reducing the power consumption of the refrigeration cycle. A refrigeration cycle having a high coefficient of performance has been proposed (Japanese Patent Application No. 2005-358659). More specifically, the refrigeration cycle according to the previous proposal includes an evaporator for evaporating the refrigerant, a compressor for compressing and discharging the refrigerant, a radiator for cooling the refrigerant discharged from the compressor, and the heat dissipation. A first pressure reducer that depressurizes the refrigerant cooled by the cooler, a refrigerant that flows out of the first pressure reducer, and a refrigerant that flows in from the evaporator are separated into a liquid phase refrigerant and a gas phase refrigerant, and a liquid phase refrigerant A refrigerating cycle having a gas-liquid separator that flows out to an evaporator side and causes a gas-phase refrigerant to flow out to the compressor side, wherein the gas-liquid separator is disposed between the gas-liquid separator and the evaporator The liquid-phase refrigerant that has flowed out of the pump is provided with pump means for pumping the refrigerant to the evaporator side.

  However, in the refrigeration cycle according to the previous proposal, the addition of a new part as an expander-pump means constituting the refrigeration cycle, and piping parts such as refrigerant pipes and seal parts for connecting the parts in the refrigeration cycle, Since the operation | work which connects those components is required, the problem that it is difficult to aim at cost reduction, size reduction, and weight reduction of a refrigerating cycle remains.

  Therefore, in view of the above points, the problem of the present invention is that the basic configuration of the refrigeration cycle can reduce the number of parts while taking advantage of the configuration as a configuration similar to the refrigeration cycle according to the above proposal, An object of the present invention is to provide a refrigeration cycle capable of reducing the cost, size and weight of the entire cycle.

  In order to solve the above problems, a refrigeration cycle according to the present invention includes an evaporator for evaporating a refrigerant, a compressor for compressing and discharging the refrigerant, a radiator for cooling the refrigerant discharged from the compressor, An expander that decompresses and expands the refrigerant cooled by the radiator, and separates the refrigerant that flows out of the expander and the refrigerant that flows in from the evaporator into a liquid-phase refrigerant and a gas-phase refrigerant, and the liquid-phase refrigerant on the evaporator side And a gas-liquid separator that causes a gas-phase refrigerant to flow out to the compressor side, wherein the gas-liquid separator flows between the gas-liquid separator and the evaporator. Pump means for pumping the liquid phase refrigerant to the evaporator side is provided, and the gas-liquid separator and at least the pump means are configured integrally. By integrally configuring the gas-liquid separator and at least the pump means, the piping in this portion can be omitted, and the cost, size and weight of this portion can be reduced.

  In this refrigeration cycle, the expander is also configured integrally with the gas-liquid separator, and the expander and the pump means can be coaxially connected. With this integrated configuration, the number of parts of the refrigeration cycle can be further reduced, the cost can be reduced, the size can be reduced, and the weight can be reduced. In addition, the coaxial connection configuration of the expander and the pump means makes it possible to use the expansion energy of the refrigerant expanding in the expander as the drive energy of the pump means, thereby reducing the power consumption of the refrigeration cycle. Thus, a more efficient refrigeration cycle can be realized.

  An axial pump can be used as the pump means. By using the axial flow pump, as shown in an embodiment described later, when the pump means and the gas-liquid separator are integrated, a more compact configuration can be easily achieved.

  Further, in the refrigeration cycle according to the present invention, a bypass passage is provided between the radiator and the gas-liquid separator to flow a part of the refrigerant by bypassing the expander. It can be set as the structure comprised integrally with a gas-liquid separator. In such a configuration, when the refrigerant pressure before the expander becomes abnormally high, an abnormal increase in the refrigerant pressure can be avoided by causing the refrigerant to flow (release) through the bypass passage. And by constructing the bypass passage integrally with the gas-liquid separator, while realizing a highly efficient refrigeration cycle, the number of parts (particularly piping) as a whole refrigeration cycle is reduced, cost reduction, size reduction, and weight reduction are achieved. It becomes possible. The bypass passage may be provided with a bypass flow rate adjusting means for adjusting the refrigerant flow rate of the bypass passage based on a physical quantity related to the state of the refrigeration cycle.

  Further, in the refrigeration cycle according to the present invention, a filter can be provided for preventing foreign matter from passing through the refrigerant passage between the radiator and the expander, and the filter is also connected to the gas-liquid separator. It can be configured integrally. With this integrated configuration, it is possible to reduce the number of parts (particularly piping) as a whole refrigeration cycle, reduce the cost, reduce the size, and reduce the weight while utilizing the function of the filter.

  Further, in the refrigeration cycle according to the present invention, a refrigerant heat exchanger for exchanging heat between the high-pressure refrigerant flowing out from the radiator and the low-pressure refrigerant flowing into the compressor is provided, as in the case of installing the internal heat exchanger in the prior art. It is good also as a structure currently provided. With such a configuration, it becomes possible to more effectively use the thermal energy in the cycle.

  Such a refrigeration cycle according to the present invention is suitable for a refrigeration cycle including a supercritical region, particularly when the refrigerant is carbon dioxide which is a natural refrigerant. The refrigeration cycle according to the present invention is particularly suitable when used as a refrigeration cycle for a vehicle air conditioner.

  According to the refrigeration cycle according to the present invention, the pump means is preferably integrated with the gas-liquid separator, including other devices and parts, that is, by having an integrated modular configuration, It becomes possible to reduce the number of parts of the refrigeration cycle using the refrigerant operating in the critical region. Through this modularization, it becomes possible to reduce the cost, size and weight of the entire refrigeration cycle.

  Hereinafter, a preferred embodiment of the present invention will be described in detail with respect to a vapor compression refrigeration cycle using carbon dioxide, which is a natural refrigerant.

  FIG. 1 shows a refrigeration cycle according to Embodiment 1 of the present invention. The refrigeration cycle 1 shown in FIG. 1 cools a compressor 2 that compresses and discharges a refrigerant, and a refrigerant discharged from the compressor 2. The radiator 3, the expander 4 that decompresses and expands the refrigerant cooled by the radiator 3, and the refrigerant that flows out of the expander 4 and the refrigerant that flows in from the evaporator 6 are separated into a liquid-phase refrigerant and a gas-phase refrigerant. At the same time, the gas-liquid separator 5 that causes the liquid-phase refrigerant to flow out to the evaporator 6 side and the gas-phase refrigerant to flow toward the compressor 2 side, and the liquid-phase refrigerant that has flowed out from the gas-liquid separator 5 evaporate to form a gas. A pump unit 7 having an evaporator 6 as a phase refrigerant, and pumping the liquid phase refrigerant separated and discharged from the gas-liquid separator 5 toward the evaporator 6 between the gas-liquid separator 5 and the evaporator 6. The gas-liquid separator 5 and at least the pump means 7 are integrated into an integrated module. Is configured as Lumpur 8 (sometimes referred to as gas-liquid separator integrated module.).

  In this embodiment, the expander 4 is also configured integrally with the gas-liquid separator 5 (incorporated in the gas-liquid separator integrated module 8), and the expander 4 and the pump means 7 are the same shaft 9. Thus, the expansion energy of the refrigerant regenerated by the expander 4 can be used as the driving energy of the pump means 7. Further, in this embodiment, a bypass passage 10 is provided between the radiator 3 and the gas-liquid separator 5 so that a part of the refrigerant is allowed to bypass the expander 4 and the bypass passage 10 is also separated from the gas-liquid separator. It is integrated with the vessel 5 and incorporated in the gas-liquid separator integrated module 8. The bypass passage 10 is provided with a bypass valve 11 as a bypass flow rate adjusting means for adjusting the refrigerant flow rate of the bypass passage 10 based on a physical quantity relating to the state of the refrigeration cycle 1. Note that a decompressor 12 may be provided between the pump means 7 and the evaporator 6 in order to make the refrigerant flowing into the evaporator 6 suitable for lower pressure evaporation. The decompressor 12 may have a mechanism that determines the degree of decompression based on information regarding the state of the refrigeration cycle 1. In this case, the mechanism may operate autonomously based on the refrigerant pressure difference between the front and rear, or may operate based on an external electric signal or pressure signal.

The configuration of the gas-liquid separator integrated module 8 will be described in more detail with reference to FIGS.
The gas-liquid separator integrated module 8 is provided with an introduction port 22 for introducing the refrigerant 21 from the radiator 3 and an outflow port 24 for feeding and outflowing the refrigerant 23 to the evaporator 6 side. The separator 5 is provided with an inflow port 26 through which the refrigerant 25 from the evaporator 6 flows in and an outflow port 28 through which the gas-phase refrigerant 27 separated by the gas-liquid separator 5 flows out to the compressor 2 side. . In the gas-liquid separator integrated module 8, in this embodiment, a filter 29 for preventing foreign matter from passing through the refrigerant passage between the radiator 3 and the expander 4 downstream of the introduction port 22. Is provided. Although the expander 4 is provided on the downstream side of the filter 29, the above-described bypass passage 10 in which the refrigerant passage is branched up to the expander 4 is formed, and the bypass valve 11 is provided in the bypass passage 10. Is provided. The bypass valve 11 constitutes a refrigerant flow rate adjustment type bypass valve in which the refrigerant flow rate changes according to the pressure difference between the front and rear. When the pressure of the high-pressure refrigerant exceeds a threshold value, the bypass valve 11 shortcuts (or pressure-adjusts) the interior of the gas-liquid separator 5 that is the high-pressure side refrigerant passage (upstream side of the bypass valve 11) and the low-pressure refrigerant passage. .

  The refrigerant that is not bypassed by the bypass passage 10 is sent to the expander 4, and the refrigerant expanded by the expander 4 is merged with the refrigerant from the bypass passage 10, and the gas-liquid separator from the inlet port 30 of the gas-liquid separator 5. 5 is introduced. The introduced refrigerant 31 merges with the introduced refrigerant 25 from the evaporator 6 described above, and is separated into the gas phase refrigerant 32 and the liquid phase refrigerant 33 in the gas-liquid separator 5. The separated gas phase refrigerant 32 is sent to the compressor 2 side from the outflow port 28 via the U-shaped internal pipe 34, and the liquid phase refrigerant 33 is sent from the outflow port 35 to the pump means 7 part. This outflow refrigerant 36 is pumped by the pump means 7 and is sent to the evaporator 6 side through the outflow port 24 described above. In this embodiment, the pump means 7 is an axial pump and is connected to the expander 4 on the same axis 9 as described above. The connecting shaft 9 is held by a bearing 43, for example, and can also be held by guide vanes of an axial flow pump 7 as a pump means. The portion incorporating the axial flow pump 7 and the interior of the gas-liquid separator 5 communicating with the axial flow pump 7 are low pressure chambers having a supercritical pressure or lower. The refrigerating machine oil 37 contained in the refrigerant is collected at the bottom of the separated liquid-phase refrigerant 33 in the gas-liquid separator 5. This refrigerating machine oil 37 is oil provided at the bottom of the internal pipe 34. It returns to the compressor 2 side through the return hole 38 and is used for lubrication.

  In the refrigeration cycle 1 configured in this way, the gas-liquid separator 5 and at least the pump means 7 are integrated into the gas-liquid separator integrated module 8 which is configured integrally, so that in this part which has been conventionally required At least piping can be omitted, the number of parts can be reduced, and the cost, size and weight of the refrigeration cycle 1 as a whole can be reduced. Further, as in the above-described embodiment, by incorporating other parts (at least any part of the filter 29, the bypass passage 10, and the expander 4) in the gas-liquid separator integrated module 8, the number of parts can be further increased. Reduction, cost reduction, size reduction, and weight reduction are possible.

  FIG. 4 shows a refrigeration cycle 41 according to Embodiment 2 of the present invention. In the refrigeration cycle 41, a refrigerant heat exchanger 42 for exchanging heat between the high-pressure refrigerant flowing out of the radiator 3 and the low-pressure refrigerant flowing into the compressor 2 is provided in a cycle having the same configuration as that of the first embodiment. It has been. With such a configuration, the heat energy in the refrigeration cycle 41 can be used more effectively, and a refrigeration cycle that is more efficient in terms of power consumption or energy can be realized. The effect obtained by the integrated configuration by the gas-liquid separator integrated module 8 is the same as in the first embodiment.

  The present invention can be applied to a vapor compression refrigeration cycle, and is particularly suitable for a refrigeration cycle using carbon dioxide, which is a natural refrigerant, as a refrigerant.

It is a schematic block diagram of the refrigerating cycle which concerns on Example 1 of this invention. FIG. 2 is an enlarged longitudinal sectional view of a gas-liquid separator integrated module part in the refrigeration cycle of FIG. 1. It is a schematic cross-sectional view of the gas-liquid separator integrated module part of FIG. It is a schematic block diagram of the refrigerating cycle which concerns on Example 2 of this invention. It is a schematic block diagram of the conventional refrigeration cycle.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Refrigeration cycle 2 Compressor 3 Radiator 4 Expander 5 Gas-liquid separator 6 Evaporator 7 Pump means 8 Gas-liquid separator integrated module 9 Shaft (connection shaft)
DESCRIPTION OF SYMBOLS 10 Bypass path 11 Bypass valve 12 Pressure reducer 29 Filter 32 Gas phase refrigerant 33 Liquid phase refrigerant 34 Internal piping 37 Refrigerating machine oil 38 Oil return hole 41 Refrigeration cycle 42 Refrigerant heat exchanger 43 Bearing

Claims (9)

  An evaporator for evaporating the refrigerant, a compressor for compressing and discharging the refrigerant, a radiator for cooling the refrigerant discharged from the compressor, an expander for decompressing and expanding the refrigerant cooled by the radiator, The refrigerant flowing out of the expander and the refrigerant flowing in from the evaporator are separated into a liquid phase refrigerant and a gas phase refrigerant, the liquid phase refrigerant is discharged to the evaporator side, and the gas phase refrigerant is discharged to the compressor side. A refrigeration cycle having a gas-liquid separator, and a pump means for pumping the liquid-phase refrigerant flowing out from the gas-liquid separator to the evaporator side between the gas-liquid separator and the evaporator. The refrigeration cycle, wherein the gas-liquid separator and at least the pump means are integrally formed.   The refrigeration cycle according to claim 1, wherein the expander is also integrally formed with the gas-liquid separator, and the expander and the pump means are connected coaxially.   The refrigeration cycle according to claim 1 or 2, wherein the pump means comprises an axial flow pump.   A bypass passage is provided between the radiator and the gas-liquid separator to flow a part of the refrigerant by bypassing the expander, and the bypass passage is also configured integrally with the gas-liquid separator. The refrigeration cycle according to any one of claims 1 to 3.   The refrigeration cycle according to claim 4, wherein the bypass passage is provided with bypass flow rate adjusting means for adjusting a refrigerant flow rate of the bypass passage based on a physical quantity related to a state of the refrigeration cycle.   A filter for preventing foreign matter from passing through a refrigerant passage between the radiator and the expander is provided, and the filter is also configured integrally with the gas-liquid separator. The refrigeration cycle according to any one of 5.   The refrigeration cycle according to any one of claims 1 to 6, further comprising a refrigerant heat exchanger that exchanges heat between the high-pressure refrigerant flowing out of the radiator and the low-pressure refrigerant flowing into the compressor.   The refrigeration cycle according to any one of claims 1 to 7, wherein the refrigerant is made of carbon dioxide.   The refrigeration cycle according to any one of claims 1 to 8, wherein the refrigeration cycle is used as a refrigeration cycle of a vehicle air conditioner.

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