JP5402164B2 - Refrigeration cycle equipment - Google Patents

Description

  The present invention is an invention of a refrigeration cycle of an air conditioner, and more particularly relates to a refrigeration apparatus having a plurality of heat exchangers having different temperature zones.

2. Description of the Related Art Conventionally, in a refrigeration apparatus having a plurality of heat exchangers having different temperature zones, which includes a high-temperature heat exchanger and a low-temperature heat exchanger, the refrigerant is supplied to each heat exchanger. There is a refrigeration apparatus provided with a high-temperature compressor as a high-temperature compression means for supplying the refrigerant and a low-temperature compressor as a low-temperature compression means for supplying a refrigerant to the low-temperature heat exchanger. (Patent Document 1)
In such a refrigeration apparatus, the temperature of the low-temperature heat exchanger is lower than that of the high-temperature heat exchanger, so the temperature of the refrigerant discharged from the low-temperature compression means may be lower than the temperature of the refrigerant discharged from the high-temperature compression means. The temperature of the refrigerant introduced into the low temperature compression means and the high temperature compression means through the heat absorber is the same.

  Here, in order to produce a low temperature and a high temperature, it is conceivable to control the refrigerant temperature with a compression means or a heat exchanger, but the refrigerant having the same temperature as the refrigerant introduced into the high temperature compression means is used as the low temperature compression means. Therefore, the heat of the refrigeration cycle including the low-temperature heat exchanger is not effectively used.

  Moreover, in the refrigeration apparatus described above, in order to increase the temperature of the condenser, it is necessary to increase the refrigerant discharge pressure from the compressor, so it is necessary to increase the compression ratio in the compressor. However, since the loss in the compressor increases when the compression ratio is increased by single-stage compression, the refrigerant is compressed by a plurality of compression means including a low-pressure compression means and a high-pressure compression means when a high discharge pressure is required. Multi-stage compression is adopted.

  However, in the case of a refrigeration apparatus that employs multi-stage compression as described above, it is possible to increase the temperature of the condenser by operating the refrigeration cycle at a high pressure, but the problem is that the discharge temperature of the compressor becomes high. was there.

JP 2008-209021 A

  An object of the present invention is to improve the operating efficiency of a refrigeration cycle in a refrigeration apparatus having a plurality of heat exchangers having different temperature zones, each of which includes a high-temperature heat exchanger and a low-temperature heat exchanger.

In order to solve the above-mentioned problems, the present invention relates to a first refrigerant circuit in which the refrigerant circulates in the order of the first compressor, the first heat exchanger, the first expansion means, and the heat absorber. A second compressor, a second heat exchanger, a second expansion means, and a second refrigerant circuit circulating in the order of the heat absorber,
An inter-refrigerant heat exchanger that exchanges heat between a part of the refrigerant downstream of the first expansion means and the second expansion means and upstream of the heat absorber with the refrigerant on the suction side of the first compressor. And the refrigerant that has passed through the inter-refrigerant heat exchanger is returned to the suction side of the second compressor.

The invention relating to claim 2 is a first refrigerant circuit in which the refrigerant circulates in the order of the first compression means, the first heat exchanger, the first expansion means, the main expansion means, the heat absorber, and the low pressure side compression means; A second refrigerant circuit that circulates in the order of the second compression means, the second heat exchanger, the second expansion means, the main expansion means, the heat absorber, and the low-pressure side compression means,
Between the refrigerants that exchange heat with a refrigerant on the downstream side of the main expansion unit and on the upstream side of the heat absorber with the refrigerant on the downstream side of the low-pressure side compression unit and on the suction side of the first compression unit A heat exchanger is provided, and the refrigerant that has passed through the inter-refrigerant heat exchanger is injected into the suction side of the second compression means.

  Furthermore, the invention relating to claim 3 is characterized in that heat is exchanged between the refrigerant on the downstream side of the heat absorber and the refrigerant on the downstream side of the first heat exchanger.

  Since the temperature of the low-temperature heat exchanger is lower than that of the high-temperature heat exchanger, the temperature of the refrigerant discharged from the low-temperature compression means may be lower than the temperature of the refrigerant discharged from the high-temperature compression means. Because the temperature of the refrigerant introduced into the means and the high-temperature compression means is the same, when the inter-refrigerant heat exchanger is not used, the refrigerant temperature is controlled by the compression means and the heat exchanger to produce a low temperature and a high temperature. There is a need.

  According to the first and second aspects of the invention, a part of the refrigerant passes through the inter-refrigerant heat exchanger that exchanges heat with the refrigerant on the suction side of the first compressor that supplies the refrigerant to the low-temperature heat exchanger. The refrigerant to be supplied to the low-temperature heat exchanger from the heat absorber through the low-temperature compression means by returning to the suction side of the second compressor that supplies the refrigerant to the high-temperature heat exchanger, and the high temperature Of the refrigerant supplied to the high temperature heat exchanger via the compression means, the heat of the refrigerant supplied to the low temperature heat exchanger is transferred to the high temperature heat exchanger before the refrigerant is introduced into the low temperature compression means. It becomes possible to give to the refrigerant | coolant supplied.

  In this way, heat unnecessary for the low temperature heat exchanger is transferred to the refrigerant sucked into the high temperature compression means before the refrigerant is sucked into the low temperature compression means and used in the high temperature heat exchanger. Therefore, the operating efficiency of the refrigeration cycle can be improved.

  In the invention according to claim 3, heat can be applied to the outlet side refrigerant of the heat absorber by exchanging heat between the outlet side refrigerant of the low temperature heat exchanger and the outlet side refrigerant of the heat absorber. In addition, it is possible to obtain supercooling of the refrigerant that has passed through the low-temperature heat exchanger and at the same time to apply heat to the refrigerant that has been decompressed by the expansion means.

It is explanatory drawing of the refrigerating cycle which is an Example of this invention. It is explanatory drawing of the refrigerating cycle which is the other Example of this invention.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. As an example, a refrigeration cycle apparatus that is used in an air conditioner or the like to generate hot water and performs multi-stage compression will be described as an example.

  FIG. 1 is an explanatory view of a refrigeration cycle apparatus showing a first embodiment according to the present invention, and FIG. 2 is an explanatory view showing a second embodiment according to the present invention. These refrigeration cycle apparatuses include a low-temperature heat exchanger as the first heat exchanger 41 and a high-temperature heat exchanger as the second heat exchanger 42, and the second heat exchange from the first heat exchanger 41 A water circuit 71 is provided to circulate water in the order of the vessel 42 to obtain hot water.

  By circulating water in the order from the first heat exchanger 41 to the second heat exchanger 42, the water and the refrigerant are passed through each heat exchanger in order compared to the case where heat is exchanged between the water and the refrigerant using only the high-temperature heat exchanger. Since the temperature difference between the water and the refrigerant can be reduced, the heat exchange efficiency of the refrigerant and water can be increased.

  As shown in FIG. 1, in the refrigeration cycle apparatus in the first embodiment, the refrigerant is a low-temperature compressor 11 as a first compressor, a first heat exchanger 41, a first expansion means 21, a main expansion means 23, an endothermic heat. The first refrigerant circuit circulating in the order of the compressor 43, the low-pressure side compressor 10, the high-temperature compressor 12 as the second compressor, the second heat exchanger 42, the second expansion means 22, the main expansion means 23, the heat absorption And a second refrigerant circuit that circulates in the order of the low-pressure compressor 10, and a part of the refrigerant between the main expansion means 10 and the first expansion means 21 is disposed downstream of the low-pressure compressor 10. The main refrigerant heat exchanger 33 for exchanging heat with the refrigerant on the suction side of the first compressor 11 is provided, and the refrigerant that has passed through the main refrigerant heat exchanger 33 is injected into the suction side of the high-temperature compressor 12. The refrigeration cycle apparatus is configured to inject through the port 61.

  Thus, since a part of the refrigerant between the main expansion means 10 and the first expansion means 21 is injected into the suction side of the high temperature compressor 12, the temperature of the refrigerant discharged from the high temperature compressor 12 becomes high. Can be prevented.

  In addition, since the main refrigerant heat exchanger 33 exchanges heat between the refrigerant on the suction side of the low-temperature compressor 11 and the refrigerant injected into the suction side of the high-temperature compressor 12, the heat of the refrigerant in the low-temperature side refrigerant circuit. Can be provided to the high temperature side refrigerant circuit.

  For example, when the hot water is generated in the water circuit 71 in the low-temperature side refrigerant circuit including the first heat exchanger 41 and the high-temperature side refrigerant circuit including the second heat exchanger 42, the temperature of the first heat exchanger 41 is intentionally set to the second temperature. It is lower than the heat exchanger 42. According to the configuration as in the first embodiment described above, in such an operating situation, heat unnecessary for the first heat exchanger 41 is given to the high-temperature side refrigerant circuit including the second heat exchanger 42. It becomes possible.

  Further, heat is exchanged between the refrigerant on the downstream side of the heat absorber 43 and the refrigerant on the downstream side of the first heat exchanger 41 using the second heat exchanger 32 between refrigerants. By performing this heat exchange, the refrigerant that has passed through the first heat exchanger 41 can be supercooled, and at the same time, the refrigerant that has passed through the heat absorber 43 can be superheated.

  By applying heat to the refrigerant that has passed through the heat absorber 43 in this manner, for example, even if the liquid phase refrigerant remains in the refrigerant that has passed through the heat absorber 43, the second inter-refrigerant heat exchanger 32 further absorbs heat. This makes it possible to obtain a gas phase state.

  Further, the refrigerant introduced into the main inter-refrigerant heat exchanger 33 from between the main expansion means 23 and the first expansion means 21, and the refrigerant on the downstream side of the second heat exchanger 42, the first Heat is exchanged using the inter-refrigerant heat exchanger 31. By performing this heat exchange, it is possible to obtain supercooling of the refrigerant that has passed through the second heat exchanger 42 and at the same time to apply heat to the refrigerant introduced into the main inter-refrigerant heat exchanger 33.

  A first flow rate control valve 51 and a second flow rate control valve 52 are arranged between the low pressure side compressor 10 and the low temperature compressor 11 and between the low pressure side compressor 10 and the high temperature compressor 12. ing.

Further, a third flow rate adjusting valve 53 is arranged in the refrigerant circuit that injects from between the main expansion means 23 and the first expansion means 21 to the suction side of the high-temperature compression 12 through the main refrigerant heat exchanger 33. ing.
Thereby, the refrigerant | coolant flow volume in the 1st heat exchanger 41, the 2nd heat exchanger 42, and the heat exchanger between refrigerant | coolants is adjusted suitably.

  Here, the heat absorber 43 may exchange heat with the outside air using a blower (not shown), or may supply heat to the refrigerant from a heat source such as an electric heater or another refrigeration cycle.

  In the second embodiment shown in FIG. 2, an ejector 24 is used as the main expansion means, and the refrigerant introduced into the ejector 24 is separated into a gas-phase refrigerant and a liquid-phase refrigerant by a gas-liquid separator 62. Supplied to the low-pressure compressor 10. The liquid-phase refrigerant separated by the gas-liquid separator 62 exchanges heat with the refrigerant on the downstream side of the first heat exchanger 41 by the second inter-refrigerant heat exchanger 32, and is then heat-exchanged by the heat absorber 43. Introduced to 24.

  Thus, since the ejector 24 is used as the expansion means, energy loss during decompression can be reduced.

  Further, since the liquid-phase refrigerant separated by the gas-liquid separator 62 is heat-exchanged with the refrigerant on the downstream side of the first heat exchanger 41, more heat is absorbed by the liquid refrigerant together with the heat absorption by the heat absorber 43. Can be given.

  Further, after the refrigerant pressure of the refrigerant circuit having the high-temperature heat exchanger is reduced by the second expansion means 22, the refrigerant is joined with the refrigerant of the refrigerant circuit having the low-temperature heat exchanger, and the combined refrigerant pressure is changed to the first expansion means. The pressure is reduced at 21. This is because the refrigerant pressure of the refrigerant circuit having the high-temperature heat exchanger is higher than the refrigerant pressure of the refrigerant circuit having the low-temperature heat exchanger, so the high-temperature heat exchanger is installed upstream of the first expansion means 21. This is because the pressure of the refrigerant circuit having the refrigerant circuit is reduced to be the same as the refrigerant pressure of the refrigerant circuit having the low-temperature heat exchanger and then reduced by the first expansion means 21.

  In addition, the same reference numerals are given to configurations common to the first embodiment, and detailed description thereof is omitted.

  In the embodiment described above, a refrigeration cycle apparatus having a low-pressure side compressor and performing multi-stage compression has been described. However, the present invention is not limited to this, for example, the first expansion means 21 without using the main expansion means 23. Similarly, in the refrigeration cycle apparatus in which the pressure is reduced only by the second expansion means 22 and the refrigerant is compressed only by the low temperature compressor 11 and the high temperature compressor 12 without using the low pressure compressor 10. Applicable.

10 Low pressure compressor
11 Low temperature compressor
12 High temperature compressor
21 First expansion means
22 Second expansion means
23 Main expansion means
24 Ejector
31 1st refrigerant heat exchanger
32 Second refrigerant heat exchanger
33 Main refrigerant heat exchanger
41 1st heat exchanger
42 Second heat exchanger
43 heat sink
51 1st flow control valve
52 Second flow control valve
53 Third flow control valve
61 Injection port
62 Gas-liquid separator
71 Water circuit

Claims (3)

The first refrigerant circuit in which the refrigerant circulates in the order of the first compressor, the first heat exchanger, the first expansion means, and the heat absorber, the second compressor, the second heat exchanger, the second expansion means, and the heat absorption A second refrigerant circuit that circulates in the order of the vessel, and a branching portion into which the refrigerant from the heat absorber branches into the first compressor and the second compressor ,
A refrigerant-to-refrigerant heat exchanger that exchanges a part of the refrigerant between the first expansion means and the heat absorber with the refrigerant on the suction side of the first compressor is provided, and passes through the refrigerant-to-refrigerant heat exchanger. Return the refrigerant to the suction side of the second compressor ,
A refrigeration cycle apparatus in which a flow rate adjusting valve is provided between the branch portion and the inter-refrigerant heat exchanger and between the branch portion and the second compressor . A first refrigerant circuit in which refrigerant circulates in the order of the first compression means, the first heat exchanger, the first expansion means, the main expansion means, the heat absorber, and the low pressure side compression means, the second compression means, and the second heat exchange A second refrigerant circuit that circulates in the order of the compressor, the second expansion means, the main expansion means, the heat absorber, and the low-pressure side compression means, and the refrigerant from the low-pressure side compression means is the first compressor and the second A branching portion branched to the compressor ,
An inter-refrigerant heat exchanger that exchanges heat between a part of the refrigerant between the main expansion means and the first expansion means with the refrigerant on the downstream side of the low-pressure side compression means and on the suction side of the first compression means. Injecting the refrigerant that has passed through the inter-refrigerant heat exchanger to the suction side of the second compression means ,
A refrigeration cycle apparatus provided with a flow rate adjusting valve between the low pressure side compression means and the inter-refrigerant heat exchanger, and between the low pressure side compression means and the second compressor . The refrigeration cycle apparatus according to claim 1 or 2, wherein heat is exchanged between the refrigerant on the downstream side of the heat absorber and the refrigerant on the downstream side of the first heat exchanger.

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