JP2006189254A - Refrigeration cycle device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To avoid the constraint that the density ratio is constant as much as possible, and to obtain high power recovering effect in a wide operation range. <P>SOLUTION: This refrigeration cycle device uses carbon dioxide as a refrigerant and has a compressor, an outdoor heat exchanger, an expander and an indoor heat exchanger. The refrigeration cycle device is provided with an injection circuit for introducing a high pressure refrigerant in a halfway of an expansion process of the expander. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a refrigeration cycle apparatus using carbon dioxide as a refrigerant and including a compressor, an outdoor heat exchanger, an expander, and an indoor heat exchanger.

The mass circulation amount of the refrigerant circulating through the refrigeration cycle apparatus is the same at any point in the refrigeration cycle. If the suction density of the refrigerant passing through the compressor is DC and the suction density of the refrigerant passing through the expander is DE, DE / DC ( The density ratio is always kept constant.
On the other hand, ozone depletion is zero and global warming coefficient much smaller compared to CFCs, carbon dioxide (hereinafter, CO of ₂₎ Although the refrigeration cycle apparatus using the refrigerant is focused in recent years, CO ₂ When the refrigerant has a critical temperature as low as 31.06 ° C. and a temperature higher than this temperature is used, the CO ₂ refrigerant is condensed on the high-pressure side (compressor outlet to radiator to decompressor inlet) of the refrigeration cycle apparatus. This is a supercritical state in which no refrigeration occurs, and the operating efficiency of the refrigeration cycle apparatus is reduced as compared with conventional refrigerants. Therefore, in the refrigeration cycle apparatus using the CO ₂ refrigerant, it is important to maintain the optimum COP, and when the operation condition changes, the operation state (refrigerant pressure, temperature) optimum for the operation condition is obtained. It is necessary.
However, when an expander is provided in the refrigeration cycle apparatus and the power recovered by the expander is used as part of the driving force of the compressor, the rotation speed of the expander and the compressor must be the same. In an expander optimally designed with a predetermined density ratio, it is difficult to maintain an optimal COP when the operating conditions change.
Therefore, a configuration has been proposed in which an optimum COP is maintained by providing a bypass pipe that bypasses the expander and controlling the amount of refrigerant flowing into the expander (see, for example, Patent Document 1 and Patent Document 2).

JP 2000-234814 A (paragraph numbers (0024) (0025) FIG. 1) JP 2001-116371 A (paragraph number (0023) FIG. 1)

However, as the flow rate of refrigerant flowing into the expander increases from the design optimum flow rate, the amount of refrigerant passing through the bypass increases, and as a result, the power that can be recovered cannot be recovered sufficiently. have.
By using the power recovered by the expander as the driving force of an auxiliary compressor that is different from the compressor, it is possible to remove the restriction that the rotation speed of the expander and the compressor must be the same. is there. However, even when the auxiliary compressor is driven by the expander in this way, the density ratio is limited and it is still necessary to control the amount of refrigerant flowing into the expander.

Therefore, an object of the present invention is to avoid the restriction of a constant density ratio as much as possible and to obtain a high power recovery effect in a wide operation range.
In particular, an object of the present invention is to perform high-efficiency power recovery by increasing the flow rate of refrigerant per one expansion process by introducing a high-pressure refrigerant in the middle of the expansion process.

The refrigeration cycle apparatus of the present invention according to claim 1 is a refrigeration cycle apparatus using carbon dioxide as a refrigerant, and comprising a compressor, an outdoor heat exchanger, an expander, and an indoor heat exchanger, wherein the expansion An injection circuit for introducing a high-pressure refrigerant is provided in the middle of the expansion process of the machine.
According to a second aspect of the present invention, in the refrigeration cycle apparatus according to the first aspect, an adjustment valve for adjusting a refrigerant amount from the injection circuit is provided.
According to a third aspect of the present invention, in the refrigeration cycle apparatus according to the first aspect, a pre-expansion valve is provided on the refrigerant inflow side of the expander.
The present invention as set forth in claim 1 is characterized in that, in the refrigeration cycle apparatus according to claim 1, a sub-expander is provided on the refrigerant inflow side of the expander.
According to a fifth aspect of the present invention, in the refrigeration cycle apparatus according to the first aspect, a sub-expander is provided on the refrigerant outflow side of the expander.
A sixth aspect of the present invention is the refrigeration cycle apparatus according to the fourth or fifth aspect, wherein a generator is connected to the sub-expander.
According to a seventh aspect of the present invention, in the refrigeration cycle apparatus according to any one of the first to fifth aspects, the power recovered by the expander is used for driving the compressor.
The present invention according to claim 8 is the refrigeration cycle apparatus according to claim 7, wherein an auxiliary compressor is provided on the suction side of the compressor or the discharge side of the compressor, and the power recovered by the expander is It is used as power for driving the auxiliary compressor instead of the compressor.
According to a ninth aspect of the present invention, in the refrigeration cycle apparatus according to any one of the first to fifth aspects, the first four-way valve to which a discharge side pipe and a suction side pipe of the compressor are connected; A second four-way valve to which a discharge side pipe and a suction side pipe of the expander are connected, and the first four-way valve allows the refrigerant discharged from the compressor to be discharged from the indoor heat exchanger or the indoor heat exchanger. Alternatively, the direction of the refrigerant flowing through the expander by the second four-way valve is always the same.
According to a tenth aspect of the present invention, in the refrigeration cycle apparatus according to the eighth aspect, a first four-way valve to which a discharge side pipe and a suction side pipe of the compressor and the auxiliary compressor are connected, and the expander A second four-way valve to which a discharge side pipe and a suction side pipe are connected, and the first four-way valve allows the refrigerant discharged from the compressor and the auxiliary compressor to be discharged from the indoor heat exchanger or the chamber. Alternatively, the refrigerant flows through the inner heat exchanger selectively, and the direction of the refrigerant flowing through the expander and the sub expander is always set to the same direction by the second four-way valve.

  As described above, according to the present invention, by controlling the amount of refrigerant from the injection circuit, the refrigerant flow rate at the outlet of the expander can be adjusted, and highly efficient power recovery can be performed.

In the first embodiment of the present invention, an injection circuit for introducing a high-pressure refrigerant is provided in the middle of the expansion process of the expander. According to this embodiment, when it is necessary to increase the refrigerant flow rate without changing the rotation speed of the expander, the refrigerant flow rate per one expansion process can be increased by introducing the refrigerant from the injection circuit. And efficient power recovery can be performed.
In the second embodiment according to the present invention, in the first embodiment, an adjustment valve for adjusting the amount of refrigerant from the injection circuit is provided. By controlling the amount of refrigerant from the injection circuit, one expansion is achieved. The refrigerant flow rate per process can be optimally adjusted, and power recovery with high efficiency can be performed.
The third embodiment according to the present invention includes, in the first embodiment, a pre-expansion valve that reduces the amount of refrigerant flowing into the expander, and the refrigerant flow rate without changing the rotation speed of the expander. When it is necessary to decrease the refrigerant flow rate, the refrigerant flow rate per expansion process can be reduced by reducing the opening of the pre-expansion valve.
In the fourth embodiment of the present invention, the sub-expander is provided on the refrigerant inflow side of the expander in the first embodiment. The state of the refrigerant can be adjusted, and the amount of refrigerant flowing through the expander can be adjusted optimally. Therefore, power recovery can be performed efficiently in the expander, and expansion power can also be recovered in the sub-expander that performs pre-expansion.
In the fifth embodiment of the present invention, the sub-expander is provided on the discharge side of the expander in the first embodiment, and the sub-expander is additionally expanded to optimize the expander outlet pressure. Can be controlled. Therefore, power recovery can be performed efficiently in the expander, and expansion power can also be recovered in the sub-expander that performs additional expansion.
The sixth embodiment according to the present invention is such that a generator is connected to the sub-expander in the first embodiment, and the sub-expander is changed by changing the torque of the generator of the sub-expander. The amount of refrigerant flowing can be changed, and the amount of refrigerant flowing through the expander can be adjusted to an optimum COP.
In the seventh embodiment according to the present invention, the power recovered by the expander can be used for driving the compressor in the first to fifth embodiments.
In the eighth embodiment according to the present invention, the power recovered by the expander in the seventh embodiment can be used as power for driving the auxiliary compressor.
According to a ninth embodiment of the present invention, in the first to fifth embodiments, a first four-way valve to which a discharge side pipe and a suction side pipe of a compressor are connected, and a discharge side pipe of an expander A second four-way valve connected to the suction side pipe, and the first four-way valve allows the refrigerant discharged from the compressor to flow selectively to the indoor heat exchanger or the indoor heat exchanger, Since the direction of the refrigerant flowing through the expander is always the same direction by the valve, the first to fifth embodiments can be used as an air conditioning apparatus for air conditioning.
According to a tenth embodiment of the present invention, in the eighth embodiment, a first four-way valve to which a discharge side pipe and a suction side pipe of a compressor and an auxiliary compressor are connected, and a discharge side pipe of an expander And a second four-way valve to which the suction side pipe is connected, and the refrigerant discharged from the compressor and the auxiliary compressor is selectively used as an indoor heat exchanger or an indoor heat exchanger by the first four-way valve. The eighth embodiment can be used as a cooling / heating type air conditioner by flowing the refrigerant and flowing the expander by the second four-way valve so that the direction of the refrigerant is always the same.

Hereinafter, a refrigeration cycle apparatus according to an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a configuration diagram of a heat pump type air conditioner according to the present embodiment.
As shown in the figure, the heat pump type air conditioner according to the present embodiment uses a CO ₂ refrigerant as a refrigerant, a compressor 1 having a motor 12, an outdoor heat exchanger 3, an expander 6, and an indoor side. It is comprised from the refrigerant circuit which connected the heat exchanger 8 with piping.
A pre-expansion valve 5 is provided on the inflow side of the expander 6.
In addition, the refrigerant circuit is provided with an injection circuit 20 that introduces high-pressure refrigerant on the outlet side of the outdoor heat exchanger 3 in the middle of the expansion process of the expander 6, and the injection circuit 20 flows through the injection circuit 20. An adjustment valve 7 for adjusting the amount of refrigerant is provided.
Moreover, the drive shaft of the expander 6 and the drive shaft of the compressor 1 are connected, and the compressor 1 uses the power recovered by the expander 6 for driving.

The operation of the heat pump type air conditioner according to this embodiment will be described below.
The refrigerant is compressed and discharged at a high temperature and high pressure by the compressor 1 driven by the motor 12, and is introduced into the outdoor heat exchanger 3. In the outdoor heat exchanger 3, since the CO ₂ refrigerant is in a supercritical state, it does not enter a gas-liquid two-phase state but radiates heat to an external fluid such as air or water. Thereafter, the CO ₂ refrigerant is introduced into the pre-expansion valve 5 and the expander 6 and decompressed by the pre-expansion valve 5 and the expander 6. The power recovered by the expander 6 during this decompression is used to drive the compressor 1. At this time, for example, the optimum refrigerant amount flowing into the expander 6 is calculated from the high-pressure refrigerant temperature and high-pressure refrigerant pressure detected at the outlet side of the outdoor heat exchanger 3, the refrigerant evaporation pressure, the rotation speed of the compressor 1, and the like. When the refrigerant flow rate is smaller than the optimum refrigerant amount, the opening amount of the adjusting valve 7 is increased to increase the refrigerant amount flowing through the injection circuit 20, thereby increasing the refrigerant flow rate per expansion process of the expander 6. On the other hand, when the refrigerant flow rate is larger than the calculated optimum refrigerant amount, the opening degree of the pre-expansion valve 5 is reduced to reduce the refrigerant flow rate flowing into the inlet of the expander 6.
The CO ₂ refrigerant decompressed by the pre-expansion valve 5 and the expander 6 evaporates and absorbs heat in the indoor heat exchanger 8. Indoor cooling is performed by this heat absorption. The refrigerant that has been evaporated is sucked into the compressor 1.
As described above, according to the present embodiment, the refrigerant flow rate in one expansion process can be adjusted by controlling the refrigerant amount from the injection circuit 20, and the refrigerant flow rate flowing into the expander 6 is higher than the design flow rate. When the amount of the refrigerant is too large, the density of the pre-expansion valve 5 can be reduced to reduce the flow rate of the refrigerant flowing into the expander 6. Therefore, power recovery can be performed efficiently in the expander 6, and higher power recovery can be performed from the refrigeration cycle.

Hereinafter, a refrigeration cycle apparatus according to another embodiment of the present invention will be described with respect to a heat pump type air conditioning apparatus with reference to the drawings.
FIG. 2 is a configuration diagram of the heat pump type air conditioning apparatus according to the present embodiment.
As shown in the figure, the heat pump air-conditioning type air conditioner according to the present embodiment uses a CO ₂ refrigerant as a refrigerant, a compressor 1 having a motor 12, an outdoor heat exchanger 3, an expander 6, It is comprised from the refrigerant circuit which connected the indoor side heat exchanger 8 with piping.
A pre-expansion valve 5 is provided on the inflow side of the expander 6.
In addition, the refrigerant circuit is provided with an injection circuit 20 that introduces high-pressure refrigerant on the outlet side of the outdoor heat exchanger 3 in the middle of the expansion process of the expander 6, and the injection circuit 20 flows through the injection circuit 20. An adjustment valve 7 for adjusting the amount of refrigerant is provided.
Moreover, the drive shaft of the expander 6 and the drive shaft of the compressor 1 are connected, and the compressor 1 uses the power recovered by the expander 6 for driving.
The refrigerant circuit is connected to the first four-way valve 2 to which the discharge side pipe and the suction side pipe of the compressor 1 are connected, and to the suction side pipe of the pre-expansion valve 5 and the discharge side pipe of the expander 6. And a second four-way valve 4 to which an injection circuit 20 is connected.

The operation of the heat pump type air conditioning apparatus according to this embodiment will be described below.
First, the cooling operation mode using the outdoor heat exchanger 3 as a radiator and the indoor heat exchanger 8 as an evaporator will be described. The refrigerant flow in the cooling operation mode is indicated by solid line arrows in the figure.
The refrigerant in the cooling operation mode is compressed and discharged at a high temperature and a high pressure by the compressor 1 driven by the motor 12, and is introduced into the outdoor heat exchanger 3 through the first four-way valve 2. In the outdoor heat exchanger 3, since the CO ₂ refrigerant is in a supercritical state, it does not enter a gas-liquid two-phase state but radiates heat to an external fluid such as air or water. Thereafter, the CO ₂ refrigerant is introduced into the pre-expansion valve 5 and the expander 6 and decompressed by the pre-expansion valve 5 and the expander 6. The power recovered by the expander 6 during this decompression is used to drive the compressor 1. At this time, for example, the optimum refrigerant amount flowing into the expander 6 is calculated from the high-pressure refrigerant temperature and high-pressure refrigerant pressure detected at the outlet side of the outdoor heat exchanger 3, the refrigerant evaporation pressure, the rotation speed of the compressor 1, and the like. When the refrigerant flow rate is smaller than the optimum refrigerant amount, the opening amount of the adjusting valve 7 is increased to increase the refrigerant amount flowing through the injection circuit 20, thereby increasing the refrigerant flow rate per expansion process of the expander 6. On the other hand, when the refrigerant flow rate is larger than the calculated optimum refrigerant amount, the opening degree of the pre-expansion valve 5 is reduced to reduce the refrigerant flow rate flowing into the inlet of the expander 6.
The CO ₂ refrigerant depressurized by the pre-expansion valve 5 and the expander 6 is guided to the indoor heat exchanger 8 via the second four-way valve 4 and is evaporated and absorbs heat in the indoor heat exchanger 8. . Indoor cooling is performed by this heat absorption. The refrigerant that has been evaporated is sucked into the compressor 1.

Next, the heating operation mode using the outdoor heat exchanger 3 as an evaporator and the indoor heat exchanger 8 as a radiator will be described. The refrigerant flow in the heating operation mode is indicated by a wavy arrow in the figure.
The refrigerant in the heating operation mode is compressed and discharged at a high temperature and high pressure by the compressor 1 driven by the motor 12, and is introduced into the indoor heat exchanger 8 through the first four-way valve 2. In the indoor heat exchanger 8, since the CO ₂ refrigerant is in a supercritical state, it does not enter a gas-liquid two-phase state, but dissipates heat to an external fluid such as air or water. Heating is performed. Thereafter, the CO ₂ refrigerant is introduced into the pre-expansion valve 5 and the expander 6 and decompressed by the pre-expansion valve 5 and the expander 6. The power recovered by the expander 6 during this decompression is used to drive the compressor 1. At this time, for example, the optimum refrigerant amount flowing into the expander 6 is calculated from the high-pressure refrigerant temperature and the high-pressure refrigerant pressure detected at the outlet side of the indoor heat exchanger 8, the refrigerant evaporation pressure, the rotation speed of the compressor 1, and the like. When the refrigerant flow rate is smaller than the optimum refrigerant amount, the opening amount of the adjustment valve 7 is increased to increase the refrigerant amount flowing to the injection circuit 20, thereby increasing the refrigerant flow rate per expansion process of the expander 6. On the other hand, when the refrigerant flow rate is larger than the calculated optimum refrigerant amount, the opening degree of the pre-expansion valve 5 is reduced to reduce the refrigerant flow rate flowing into the inlet of the expander 6.
The CO ₂ refrigerant decompressed by the pre-expansion valve 5 and the expander 6 is guided to the outdoor heat exchanger 3 via the second four-way valve 4 and is evaporated and absorbs heat in the outdoor heat exchanger 3. The evaporated refrigerant is sucked into the compressor 1 via the first four-way valve 2.
As described above, according to the present embodiment, as in the above embodiment, power can be recovered efficiently in the expander 6, higher power can be recovered from the refrigeration cycle, and the first four-way valve By providing 2 and the 2nd four-way valve 4, it can utilize as an air-conditioning type air conditioner.

Hereinafter, a refrigeration cycle apparatus according to another embodiment of the present invention will be described with respect to a heat pump type air conditioning apparatus with reference to the drawings.
FIG. 3 is a configuration diagram of the heat pump air-conditioning type air conditioner according to the present embodiment.
As shown in the figure, the heat pump air-conditioning type air conditioner according to the present embodiment uses a CO ₂ refrigerant as a refrigerant, a compressor 1 having a motor 12, an outdoor heat exchanger 3, an expander 6, It is comprised from the refrigerant circuit which connected the indoor side heat exchanger 8 with piping.
A sub expander 23 is provided on the inflow side of the expander 6, and a generator 24 is connected to a drive shaft of the sub expander 23.
In addition, the refrigerant circuit is provided with an injection circuit 20 that introduces high-pressure refrigerant on the outlet side of the outdoor heat exchanger 3 in the middle of the expansion process of the expander 6, and the injection circuit 20 flows through the injection circuit 20. An adjustment valve 7 for adjusting the amount of refrigerant is provided.
Moreover, the drive shaft of the expander 6 and the drive shaft of the compressor 1 are connected, and the compressor 1 uses the power recovered by the expander 6 for driving.
The refrigerant circuit is connected to the first four-way valve 2 to which the discharge side pipe and the suction side pipe of the compressor 1 are connected, and to the suction side pipe of the sub expander 23 and the discharge side pipe of the expander 6. And a second four-way valve 4 to which an injection circuit 20 is connected.

The operation of the heat pump type air conditioning apparatus according to this embodiment will be described below.
First, the cooling operation mode using the outdoor heat exchanger 3 as a radiator and the indoor heat exchanger 8 as an evaporator will be described. The refrigerant flow in the cooling operation mode is indicated by solid line arrows in the figure.
The refrigerant in the cooling operation mode is compressed and discharged at a high temperature and a high pressure by the compressor 1 driven by the motor 12, and is introduced into the outdoor heat exchanger 3 through the first four-way valve 2. In the outdoor heat exchanger 3, since the CO ₂ refrigerant is in a supercritical state, it does not enter a gas-liquid two-phase state but radiates heat to an external fluid such as air or water. Thereafter, the CO ₂ refrigerant is introduced into the sub-expander 23 and the expander 6 and decompressed by the sub-expander 23 and the expander 6. The power recovered by the expander 6 during this decompression is used to drive the compressor 1. At this time, for example, the optimum refrigerant amount flowing into the expander 6 is calculated from the high-pressure refrigerant temperature and high-pressure refrigerant pressure detected at the outlet side of the outdoor heat exchanger 3, the refrigerant evaporation pressure, the rotation speed of the compressor 1, and the like. When the refrigerant flow rate is smaller than the optimum refrigerant amount, the opening amount of the adjusting valve 7 is increased to increase the refrigerant amount flowing through the injection circuit 20, thereby increasing the refrigerant flow rate per expansion process of the expander 6. On the other hand, when the refrigerant flow rate is larger than the calculated optimum refrigerant amount, the torque (generator load) of the generator 24 is increased to reduce the refrigerant flow rate flowing into the inlet of the expander 6.
The CO ₂ refrigerant decompressed by the sub-expander 23 and the expander 6 is guided to the indoor heat exchanger 8 via the second four-way valve 4 and is evaporated and absorbs heat in the indoor heat exchanger 8. . Indoor cooling is performed by this heat absorption. The refrigerant that has been evaporated is sucked into the compressor 1.

Next, the heating operation mode using the outdoor heat exchanger 3 as an evaporator and the indoor heat exchanger 8 as a radiator will be described. The refrigerant flow in the heating operation mode is indicated by a wavy arrow in the figure.
The refrigerant in the heating operation mode is compressed and discharged at a high temperature and high pressure by the compressor 1 driven by the motor 12, and is introduced into the indoor heat exchanger 8 through the first four-way valve 2. In the indoor heat exchanger 8, since the CO ₂ refrigerant is in a supercritical state, it does not enter a gas-liquid two-phase state, but dissipates heat to an external fluid such as air or water. Heating is performed. Thereafter, the CO ₂ refrigerant is introduced into the sub-expander 23 and the expander 6 and decompressed by the sub-expander 23 and the expander 6. The power recovered by the expander 6 during this decompression is used to drive the compressor 1. At this time, for example, the optimum refrigerant amount flowing into the expander 6 is calculated from the high-pressure refrigerant temperature and the high-pressure refrigerant pressure detected at the outlet side of the indoor heat exchanger 8, the refrigerant evaporation pressure, the rotation speed of the compressor 1, and the like. When the refrigerant flow rate is smaller than the optimum refrigerant amount, the opening amount of the adjustment valve 7 is increased to increase the refrigerant amount flowing to the injection circuit 20, thereby increasing the refrigerant flow rate per expansion process of the expander 6. On the other hand, when the refrigerant flow rate is larger than the calculated optimum refrigerant amount, the torque (generator load) of the generator 24 is increased to reduce the refrigerant flow rate flowing into the expander 6.
The CO ₂ refrigerant decompressed by the sub-expander 23 and the expander 6 is guided to the outdoor heat exchanger 3 via the second four-way valve 4 and is evaporated and absorbs heat in the outdoor heat exchanger 3. The evaporated refrigerant is sucked into the compressor 1 via the first four-way valve 2.
As described above, according to this embodiment, by controlling the amount of refrigerant from the injection circuit 20, the refrigerant flow rate at the outlet of the expander 6 can be adjusted, while the generator connected to the sub expander 23. The amount of refrigerant flowing through the expander 6 can be controlled by adjusting the inlet pressure of the expander 6 by changing the torque of 24 (that is, the load of the generator). Therefore, power can be recovered efficiently in the expander 6, and higher power can be recovered from the refrigeration cycle by using the power recovered from the sub-expander 23 for power generation by the generator 24.

Hereinafter, a refrigeration cycle apparatus according to another embodiment of the present invention will be described with respect to a heat pump type air conditioning apparatus with reference to the drawings.
FIG. 4 is a configuration diagram of the heat pump type air conditioning apparatus according to the present embodiment.
As shown in the figure, the heat pump air-conditioning type air conditioner according to the present embodiment uses a CO ₂ refrigerant as a refrigerant, a compressor 1 having a motor 12, an outdoor heat exchanger 3, an expander 6, It is comprised from the refrigerant circuit which connected the indoor side heat exchanger 8 with piping.
A sub expander 23 is provided on the discharge side of the expander 6, and a generator 24 is connected to the drive shaft of the sub expander 23.
In addition, the refrigerant circuit is provided with an injection circuit 20 that introduces high-pressure refrigerant on the outlet side of the outdoor heat exchanger 3 in the middle of the expansion process of the expander 6, and the injection circuit 20 flows through the injection circuit 20. An adjustment valve 7 for adjusting the amount of refrigerant is provided.
Moreover, the drive shaft of the expander 6 and the drive shaft of the compressor 1 are connected, and the compressor 1 uses the power recovered by the expander 6 for driving.
The refrigerant circuit is connected to the first four-way valve 2 to which the discharge side pipe and the suction side pipe of the compressor 1 are connected, to the discharge side pipe of the sub expander 23 and to the inflow side pipe of the expander 6. And a second four-way valve 4 to which an injection circuit 20 is connected.

The operation of the heat pump type air conditioning apparatus according to this embodiment will be described below.
First, the cooling operation mode using the outdoor heat exchanger 3 as a radiator and the indoor heat exchanger 8 as an evaporator will be described. The refrigerant flow in the cooling operation mode is indicated by solid line arrows in the figure.
The refrigerant in the cooling operation mode is compressed and discharged at a high temperature and a high pressure by the compressor 1 driven by the motor 12, and is introduced into the outdoor heat exchanger 3 through the first four-way valve 2. In the outdoor heat exchanger 3, since the CO ₂ refrigerant is in a supercritical state, it does not enter a gas-liquid two-phase state but radiates heat to an external fluid such as air or water. Thereafter, the CO ₂ refrigerant is introduced into the expander 6 and the sub-expander 23 and decompressed by the expander 6 and the sub-expander 23. The power recovered by the expander 6 during this decompression is used to drive the compressor 1. At this time, for example, the optimum refrigerant amount flowing into the expander 6 is calculated from the high-pressure refrigerant temperature and high-pressure refrigerant pressure detected at the outlet side of the outdoor heat exchanger 3, the refrigerant evaporation pressure, the rotation speed of the compressor 1, and the like. When the refrigerant flow rate is smaller than the optimum refrigerant amount, the opening amount of the adjusting valve 7 is increased to increase the refrigerant amount flowing through the injection circuit 20, thereby increasing the refrigerant flow rate per expansion process of the expander 6. In this case, the torque (generator load) of the generator 24 is minimized. On the other hand, when the refrigerant flow rate is larger than the calculated optimum refrigerant amount, the adjustment valve 7 is closed, and the torque (generator load) of the generator 24 is increased to reduce the refrigerant flow rate flowing into the inlet of the expander 6.
The CO ₂ refrigerant decompressed by the sub-expander 23 and the expander 6 is guided to the indoor heat exchanger 8 via the second four-way valve 4 and is evaporated and absorbs heat in the indoor heat exchanger 8. . Indoor cooling is performed by this heat absorption. The refrigerant that has been evaporated is sucked into the compressor 1.

Next, the heating operation mode using the outdoor heat exchanger 3 as an evaporator and the indoor heat exchanger 8 as a radiator will be described. The refrigerant flow in the heating operation mode is indicated by a wavy arrow in the figure.
The refrigerant in the heating operation mode is compressed and discharged at a high temperature and high pressure by the compressor 1 driven by the motor 12, and is introduced into the indoor heat exchanger 8 through the first four-way valve 2. In the indoor heat exchanger 8, since the CO ₂ refrigerant is in a supercritical state, it does not enter a gas-liquid two-phase state, but dissipates heat to an external fluid such as air or water. Heating is performed. Thereafter, the CO ₂ refrigerant is introduced into the expander 6 and the sub-expander 23 and decompressed by the expander 6 and the sub-expander 23. The power recovered by the expander 6 during this decompression is used to drive the compressor 1. At this time, for example, the optimum refrigerant amount flowing into the expander 6 is calculated from the high-pressure refrigerant temperature and the high-pressure refrigerant pressure detected at the outlet side of the indoor heat exchanger 8, the refrigerant evaporation pressure, the rotation speed of the compressor 1, and the like. When the refrigerant flow rate is smaller than the optimum refrigerant amount, the opening amount of the adjustment valve 7 is increased to increase the refrigerant amount flowing to the injection circuit 20, thereby increasing the refrigerant flow rate per expansion process of the expander 6. In this case, the torque (generator load) of the generator 24 is minimized. On the other hand, when the refrigerant flow rate is larger than the calculated optimum refrigerant amount, the adjustment valve 7 is closed, and the torque (generator load) of the generator 24 is increased to reduce the refrigerant flow rate flowing into the inlet of the expander 6.
The CO ₂ refrigerant decompressed by the sub-expander 23 and the expander 6 is guided to the outdoor heat exchanger 3 via the second four-way valve 4 and is evaporated and absorbs heat in the outdoor heat exchanger 3. The evaporated refrigerant is sucked into the compressor 1 via the first four-way valve 2.
As described above, according to this embodiment, by controlling the amount of refrigerant from the injection circuit 20, the refrigerant flow rate at the outlet of the expander 6 can be adjusted, while the adjustment valve 7 is closed and the sub-expander is closed. The amount of refrigerant flowing through the expander 6 can be controlled by adjusting the outlet pressure of the expander 6 by changing the torque of the generator 24 connected to the load 23 (that is, the load of the generator). Therefore, power can be recovered efficiently in the expander 6, and higher power can be recovered from the refrigeration cycle by using the power recovered from the sub-expander 23 for power generation by the generator 24.

Hereinafter, a refrigeration cycle apparatus according to another embodiment of the present invention will be described with respect to a heat pump type air conditioning apparatus with reference to the drawings.
FIG. 5 is a configuration diagram of the heat pump type air conditioning apparatus according to the present embodiment.
As shown in the figure, the heat pump air-conditioning type air conditioner according to the present embodiment uses a CO ₂ refrigerant as a refrigerant, a compressor 1 having a motor 12, an outdoor heat exchanger 3, an expander 6, It is comprised from the refrigerant circuit which connected the indoor side heat exchanger 8 and the auxiliary compressor 10 with piping.
A pre-expansion valve 5 is provided on the inflow side of the expander 6.
In addition, the refrigerant circuit is provided with an injection circuit 20 that introduces high-pressure refrigerant on the outlet side of the outdoor heat exchanger 3 in the middle of the expansion process of the expander 6, and the injection circuit 20 flows through the injection circuit 20. An adjustment valve 7 for adjusting the amount of refrigerant is provided.
Further, the drive shaft of the expander 6 and the drive shaft of the auxiliary compressor 10 are connected, and the auxiliary compressor 10 is driven by the power recovered by the expander 6.
The refrigerant circuit includes a first four-way valve 2 to which a discharge side pipe of the compressor 1 and a suction side pipe of the auxiliary compressor 10 are connected, a suction side pipe of the pre-expansion valve 5 and a discharge side of the expander 6. A second four-way valve 4 to which an injection circuit 20 is connected as well as a pipe is provided.

The operation of the heat pump type air conditioning apparatus according to this embodiment will be described below.
First, the cooling operation mode using the outdoor heat exchanger 3 as a radiator and the indoor heat exchanger 8 as an evaporator will be described. The refrigerant flow in the cooling operation mode is indicated by solid line arrows in the figure.
The refrigerant in the cooling operation mode is compressed and discharged at a high temperature and a high pressure by the compressor 1 driven by the motor 12, and is introduced into the outdoor heat exchanger 3 through the first four-way valve 2. In the outdoor heat exchanger 3, since the CO ₂ refrigerant is in a supercritical state, it does not enter a gas-liquid two-phase state but radiates heat to an external fluid such as air or water. Thereafter, the CO ₂ refrigerant is introduced into the pre-expansion valve 5 and the expander 6 and decompressed by the pre-expansion valve 5 and the expander 6. The power recovered by the expander 6 during this decompression is used to drive the auxiliary compressor 10. At this time, for example, the optimum refrigerant amount flowing into the expander 6 is calculated from the high-pressure refrigerant temperature and high-pressure refrigerant pressure detected at the outlet side of the outdoor heat exchanger 3, the refrigerant evaporation pressure, the rotation speed of the compressor 1, and the like. When the refrigerant flow rate is smaller than the optimum refrigerant amount, the opening amount of the adjusting valve 7 is increased to increase the refrigerant amount flowing through the injection circuit 20, thereby increasing the refrigerant flow rate per expansion process of the expander 6. On the other hand, when the refrigerant flow rate is larger than the calculated optimum refrigerant amount, the opening degree of the pre-expansion valve 5 is reduced to reduce the refrigerant flow rate flowing into the inlet of the expander 6.
The CO ₂ refrigerant depressurized by the pre-expansion valve 5 and the expander 6 is guided to the indoor heat exchanger 8 via the second four-way valve 4 and is evaporated and absorbs heat in the indoor heat exchanger 8. . Indoor cooling is performed by this heat absorption. The evaporated refrigerant is led to the auxiliary compressor 10 through the first four-way valve 2, supercharged (charged) by the auxiliary compressor 10, and sucked into the compressor 1.

Next, the heating operation mode using the outdoor heat exchanger 3 as an evaporator and the indoor heat exchanger 8 as a radiator will be described. The refrigerant flow in the heating operation mode is indicated by a wavy arrow in the figure.
The refrigerant in the heating operation mode is compressed and discharged at a high temperature and high pressure by the compressor 1 driven by the motor 12, and is introduced into the indoor heat exchanger 8 through the first four-way valve 2. In the indoor heat exchanger 8, since the CO ₂ refrigerant is in a supercritical state, it does not enter a gas-liquid two-phase state, but dissipates heat to an external fluid such as air or water. Heating is performed. Thereafter, the CO ₂ refrigerant is introduced into the pre-expansion valve 5 and the expander 6 and decompressed by the pre-expansion valve 5 and the expander 6. The power recovered by the expander 6 during this decompression is used to drive the auxiliary compressor 10. At this time, for example, the optimum refrigerant amount flowing into the expander 6 is calculated from the high-pressure refrigerant temperature and the high-pressure refrigerant pressure detected at the outlet side of the indoor heat exchanger 8, the refrigerant evaporation pressure, the rotation speed of the compressor 1, and the like. When the refrigerant flow rate is smaller than the optimum refrigerant amount, the opening amount of the adjustment valve 7 is increased to increase the refrigerant amount flowing to the injection circuit 20, thereby increasing the refrigerant flow rate per expansion process of the expander 6. On the other hand, when the refrigerant flow rate is larger than the calculated optimum refrigerant amount, the opening degree of the pre-expansion valve 5 is reduced to reduce the refrigerant flow rate flowing into the inlet of the expander 6.
The CO ₂ refrigerant decompressed by the pre-expansion valve 5 and the expander 6 is guided to the outdoor heat exchanger 3 via the second four-way valve 4 and is evaporated and absorbs heat in the outdoor heat exchanger 3. The evaporated refrigerant is led to the auxiliary compressor 10 via the first four-way valve 2, supercharged (charged) by the auxiliary compressor 10, and sucked into the compressor 1.
As described above, according to the present embodiment, the refrigerant flow rate at the inlet of the expander 6 can be adjusted by controlling the refrigerant amount from the injection circuit 20, while the opening degree of the pre-expansion valve 5 is changed. By adjusting the inlet pressure of the expander 6, the amount of refrigerant flowing through the expander 6 can be controlled. Therefore, power recovery can be performed efficiently in the expander 6.

Hereinafter, a refrigeration cycle apparatus according to another embodiment of the present invention will be described with respect to a heat pump type air conditioning apparatus with reference to the drawings.
FIG. 6 is a configuration diagram of the heat pump type air conditioning apparatus according to the present embodiment.
As shown in the figure, the heat pump air-conditioning type air conditioner according to the present embodiment uses a CO ₂ refrigerant as a refrigerant, a compressor 1 having a motor 12, an outdoor heat exchanger 3, an expander 6, It is comprised from the refrigerant circuit which connected the indoor side heat exchanger 8 and the auxiliary compressor 10 with piping.
A sub expander 23 is provided on the inflow side of the expander 6, and a generator 24 is connected to a drive shaft of the sub expander 23.
In addition, the refrigerant circuit is provided with an injection circuit 20 that introduces high-pressure refrigerant on the outlet side of the outdoor heat exchanger 3 in the middle of the expansion process of the expander 6, and the injection circuit 20 flows through the injection circuit 20. An adjustment valve 7 for adjusting the amount of refrigerant is provided.
Further, the drive shaft of the expander 6 and the drive shaft of the auxiliary compressor 10 are connected, and the auxiliary compressor 10 is driven by the power recovered by the expander 6.
The refrigerant circuit includes a first four-way valve 2 to which a discharge side pipe of the compressor 1 and a suction side pipe of the auxiliary compressor 10 are connected, a suction side pipe of the sub expander 23, and a discharge side of the expander 6. A second four-way valve 4 to which an injection circuit 20 is connected as well as a pipe is provided.

The operation of the heat pump type air conditioning apparatus according to this embodiment will be described below.
First, the cooling operation mode using the outdoor heat exchanger 3 as a radiator and the indoor heat exchanger 8 as an evaporator will be described. The refrigerant flow in the cooling operation mode is indicated by solid line arrows in the figure.
The refrigerant in the cooling operation mode is compressed and discharged at a high temperature and a high pressure by the compressor 1 driven by the motor 12, and is introduced into the outdoor heat exchanger 3 through the first four-way valve 2. In the outdoor heat exchanger 3, since the CO ₂ refrigerant is in a supercritical state, it does not enter a gas-liquid two-phase state but radiates heat to an external fluid such as air or water. Thereafter, the CO ₂ refrigerant is introduced into the sub-expander 23 and the expander 6 and decompressed by the sub-expander 23 and the expander 6. The power recovered by the expander 6 during this decompression is used to drive the auxiliary compressor 10. At this time, for example, the optimum refrigerant amount flowing into the expander 6 is calculated from the high-pressure refrigerant temperature and high-pressure refrigerant pressure detected at the outlet side of the outdoor heat exchanger 3, the refrigerant evaporation pressure, the rotation speed of the compressor 1, and the like. When the refrigerant flow rate is smaller than the optimum refrigerant amount, the opening amount of the adjusting valve 7 is increased to increase the refrigerant amount flowing through the injection circuit 20, thereby increasing the refrigerant flow rate per expansion process of the expander 6. On the other hand, when the refrigerant flow rate is larger than the calculated optimum refrigerant amount, the torque (generator load) of the generator 24 is increased to reduce the refrigerant flow rate flowing into the inlet of the expander 6.
The CO ₂ refrigerant decompressed by the sub-expander 23 and the expander 6 is guided to the indoor heat exchanger 8 via the second four-way valve 4 and is evaporated and absorbs heat in the indoor heat exchanger 8. . Indoor cooling is performed by this heat absorption. The evaporated refrigerant is led to the auxiliary compressor 10 through the first four-way valve 2, supercharged (charged) by the auxiliary compressor 10, and sucked into the compressor 1.

Next, the heating operation mode using the outdoor heat exchanger 3 as an evaporator and the indoor heat exchanger 8 as a radiator will be described. The refrigerant flow in the heating operation mode is indicated by a wavy arrow in the figure.
The refrigerant in the heating operation mode is compressed and discharged at a high temperature and high pressure by the compressor 1 driven by the motor 12, and is introduced into the indoor heat exchanger 8 through the first four-way valve 2. In the indoor heat exchanger 8, since the CO ₂ refrigerant is in a supercritical state, it does not enter a gas-liquid two-phase state, but dissipates heat to an external fluid such as air or water. Heating is performed. Thereafter, the CO ₂ refrigerant is introduced into the sub-expander 23 and the expander 6 and decompressed by the sub-expander 23 and the expander 6. The power recovered by the expander 6 during this decompression is used to drive the auxiliary compressor 10. At this time, for example, the optimum refrigerant amount flowing into the expander 6 is calculated from the high-pressure refrigerant temperature and the high-pressure refrigerant pressure detected at the outlet side of the indoor heat exchanger 8, the refrigerant evaporation pressure, the rotation speed of the compressor 1, and the like. When the refrigerant flow rate is smaller than the optimum refrigerant amount, the opening amount of the adjustment valve 7 is increased to increase the refrigerant amount flowing to the injection circuit 20, thereby increasing the refrigerant flow rate per expansion process of the expander 6. On the other hand, when the refrigerant flow rate is larger than the calculated optimum refrigerant amount, the torque (generator load) of the generator 24 is increased to reduce the refrigerant flow rate flowing into the inlet of the expander 6.
The CO ₂ refrigerant decompressed by the sub-expander 23 and the expander 6 is guided to the outdoor heat exchanger 3 via the second four-way valve 4 and is evaporated and absorbs heat in the outdoor heat exchanger 3. The evaporated refrigerant is led to the auxiliary compressor 10 via the first four-way valve 2, supercharged (charged) by the auxiliary compressor 10, and sucked into the compressor 1.
As described above, according to this embodiment, by controlling the amount of refrigerant from the injection circuit 20, the refrigerant flow rate at the outlet of the expander 6 can be adjusted, while the generator connected to the sub expander 23. The amount of refrigerant flowing through the expander 6 can be controlled by adjusting the inlet pressure of the expander 6 by changing the torque of 24 (that is, the load of the generator). Therefore, power can be recovered efficiently in the expander 6, and higher power can be recovered from the refrigeration cycle by using the power recovered from the sub-expander 23 for power generation by the generator 24.

Hereinafter, a refrigeration cycle apparatus according to another embodiment of the present invention will be described with respect to a heat pump type air conditioning apparatus with reference to the drawings.
FIG. 7 is a configuration diagram of a heat pump type air conditioning apparatus according to the present embodiment.
As shown in the figure, the heat pump air-conditioning type air conditioner according to the present embodiment uses a CO ₂ refrigerant as a refrigerant, a compressor 1 having a motor 12, an outdoor heat exchanger 3, an expander 6, It is comprised from the refrigerant circuit which connected the indoor side heat exchanger 8 and the auxiliary compressor 10 with piping.
A sub expander 23 is provided on the discharge side of the expander 6, and a generator 24 is connected to the drive shaft of the sub expander 23.
In addition, the refrigerant circuit is provided with an injection circuit 20 that introduces high-pressure refrigerant on the outlet side of the outdoor heat exchanger 3 in the middle of the expansion process of the expander 6, and the injection circuit 20 flows through the injection circuit 20. An adjustment valve 7 for adjusting the amount of refrigerant is provided.
Further, the drive shaft of the expander 6 and the drive shaft of the auxiliary compressor 10 are connected, and the auxiliary compressor 10 is driven by the power recovered by the expander 6.
In this refrigerant circuit, the first four-way valve 2 to which the discharge side piping of the compressor 1 and the suction side piping of the auxiliary compressor 10 are connected, the discharge side piping of the sub expander 23 and the inflow side of the expander 6 are connected. A second four-way valve 4 to which an injection circuit 20 is connected as well as a pipe is provided.

The operation of the heat pump type air conditioning apparatus according to this embodiment will be described below.
First, the cooling operation mode using the outdoor heat exchanger 3 as a radiator and the indoor heat exchanger 8 as an evaporator will be described. The refrigerant flow in the cooling operation mode is indicated by solid line arrows in the figure.
The refrigerant in the cooling operation mode is compressed and discharged at a high temperature and a high pressure by the compressor 1 driven by the motor 12, and is introduced into the outdoor heat exchanger 3 through the first four-way valve 2. In the outdoor heat exchanger 3, since the CO ₂ refrigerant is in a supercritical state, it does not enter a gas-liquid two-phase state but radiates heat to an external fluid such as air or water. Thereafter, the CO ₂ refrigerant is introduced into the expander 6 and the sub-expander 23 and decompressed by the expander 6 and the sub-expander 23. The power recovered by the expander 6 during this decompression is used to drive the auxiliary compressor 10. At this time, for example, the optimum refrigerant amount flowing into the expander 6 is calculated from the high-pressure refrigerant temperature and high-pressure refrigerant pressure detected at the outlet side of the outdoor heat exchanger 3, the refrigerant evaporation pressure, the rotation speed of the compressor 1, and the like. When the refrigerant flow rate is smaller than the optimum refrigerant amount, the opening amount of the adjusting valve 7 is increased to increase the refrigerant amount flowing through the injection circuit 20, thereby increasing the refrigerant flow rate per expansion process of the expander 6. In this case, the torque (generator load) of the generator 24 is minimized. On the other hand, when the refrigerant flow rate is larger than the calculated optimum refrigerant amount, the adjustment valve 7 is closed, and the torque (generator load) of the generator 24 is increased to reduce the refrigerant flow rate flowing into the inlet of the expander 6.
The CO ₂ refrigerant decompressed by the sub-expander 23 and the expander 6 is guided to the indoor heat exchanger 8 via the second four-way valve 4 and is evaporated and absorbs heat in the indoor heat exchanger 8. . Indoor cooling is performed by this heat absorption. The evaporated refrigerant is led to the auxiliary compressor 10 through the first four-way valve 2, supercharged (charged) by the auxiliary compressor 10, and sucked into the compressor 1.

Next, the heating operation mode using the outdoor heat exchanger 3 as an evaporator and the indoor heat exchanger 8 as a radiator will be described. The refrigerant flow in the heating operation mode is indicated by a wavy arrow in the figure.
The refrigerant in the heating operation mode is compressed and discharged at a high temperature and high pressure by the compressor 1 driven by the motor 12, and is introduced into the indoor heat exchanger 8 through the first four-way valve 2. In the indoor heat exchanger 8, since the CO ₂ refrigerant is in a supercritical state, it does not enter a gas-liquid two-phase state, but dissipates heat to an external fluid such as air or water. Heating is performed. Thereafter, the CO ₂ refrigerant is introduced into the expander 6 and the sub-expander 23 and decompressed by the expander 6 and the sub-expander 23. The power recovered by the expander 6 during this decompression is used to drive the auxiliary compressor 10. At this time, for example, the optimum refrigerant amount flowing into the expander 6 is calculated from the high-pressure refrigerant temperature and the high-pressure refrigerant pressure detected at the outlet side of the indoor heat exchanger 8, the refrigerant evaporation pressure, the rotation speed of the compressor 1, and the like. When the refrigerant flow rate is smaller than the optimum refrigerant amount, the opening amount of the adjustment valve 7 is increased to increase the refrigerant amount flowing to the injection circuit 20, thereby increasing the refrigerant flow rate per expansion process of the expander 6. On the other hand, when the refrigerant flow rate is larger than the calculated optimum refrigerant amount, the adjustment valve 7 is closed, and the torque (generator load) of the generator 24 is increased to reduce the refrigerant flow rate flowing into the inlet of the expander 6.
The CO ₂ refrigerant decompressed by the sub-expander 23 and the expander 6 is guided to the outdoor heat exchanger 3 via the second four-way valve 4 and is evaporated and absorbs heat in the outdoor heat exchanger 3. The evaporated refrigerant is led to the auxiliary compressor 10 via the first four-way valve 2, supercharged (charged) by the auxiliary compressor 10, and sucked into the compressor 1.
As described above, according to this embodiment, by controlling the amount of refrigerant from the injection circuit 20, the refrigerant flow rate at the outlet of the expander 6 can be adjusted, while the adjustment valve 7 is closed and the sub-expander is closed. The amount of refrigerant flowing through the expander 6 can be controlled by adjusting the outlet pressure of the expander 6 by changing the torque of the generator 24 connected to the load 23 (that is, the load of the generator). Therefore, power can be recovered efficiently in the expander 6, and higher power can be recovered from the refrigeration cycle by using the power recovered from the sub-expander 23 for power generation by the generator 24.

Hereinafter, a refrigeration cycle apparatus according to another embodiment of the present invention will be described with respect to a heat pump type air conditioning apparatus with reference to the drawings.
FIG. 8 is a configuration diagram of the heat pump air-conditioning type air conditioner according to this embodiment.
As shown in the figure, the heat pump air-conditioning type air conditioner according to this embodiment uses a CO ₂ refrigerant as a refrigerant, a compressor 1 having a motor 12, an auxiliary compressor 10, an outdoor heat exchanger 3, and the like. The expander 6 and the indoor heat exchanger 8 are configured by a refrigerant circuit connected by piping.
A pre-expansion valve 5 is provided on the inflow side of the expander 6.
In addition, the refrigerant circuit is provided with an injection circuit 20 that introduces high-pressure refrigerant on the outlet side of the outdoor heat exchanger 3 in the middle of the expansion process of the expander 6, and the injection circuit 20 flows through the injection circuit 20. An adjustment valve 7 for adjusting the amount of refrigerant is provided.
Further, the drive shaft of the expander 6 and the drive shaft of the auxiliary compressor 10 are connected, and the auxiliary compressor 10 is driven by the power recovered by the expander 6.
The refrigerant circuit includes a first four-way valve 2 to which a suction side pipe of the compressor 1 and a discharge side pipe of the auxiliary compressor 10 are connected, a suction side pipe of the pre-expansion valve 5 and a discharge side of the expander 6. A second four-way valve 4 to which a pipe is connected and an injection circuit 20 is connected is provided.

The operation of the heat pump type air conditioning apparatus according to this embodiment will be described below.
First, the cooling operation mode using the outdoor heat exchanger 3 as a radiator and the indoor heat exchanger 8 as an evaporator will be described. The refrigerant flow in the cooling operation mode is indicated by solid line arrows in the figure.
The refrigerant in the cooling operation mode is compressed and discharged at a high temperature and high pressure by the compressor 1 driven by the motor 12, guided to the auxiliary compressor 10, and further boosted (expressor) by the auxiliary compressor 10. It is introduced into the outdoor heat exchanger 3 via the first four-way valve 2. In the outdoor heat exchanger 3, since the CO ₂ refrigerant is in a supercritical state, it does not enter a gas-liquid two-phase state but radiates heat to an external fluid such as air or water. Thereafter, the CO ₂ refrigerant is introduced into the pre-expansion valve 5, the expander 6, and the sub-expander 21, and decompressed by the pre-expansion valve 5, the expander 6, and the sub-expander 21. The power recovered by the expander 6 during this decompression is used to drive the auxiliary compressor 10. At this time, for example, the optimum refrigerant amount flowing into the expander 6 is calculated from the high-pressure refrigerant temperature and high-pressure refrigerant pressure detected at the outlet side of the outdoor heat exchanger 3, the refrigerant evaporation pressure, the rotation speed of the compressor 1, and the like. When the refrigerant flow rate is smaller than the optimum refrigerant amount, the opening amount of the adjusting valve 7 is increased to increase the refrigerant amount flowing through the injection circuit 20, thereby increasing the refrigerant flow rate per expansion process of the expander 6. On the other hand, when the refrigerant flow rate is larger than the calculated optimum refrigerant amount, the opening degree of the pre-expansion valve 5 is reduced to reduce the refrigerant flow rate flowing into the inlet of the expander 6.
The CO ₂ refrigerant depressurized by the pre-expansion valve 5 and the expander 6 is guided to the indoor heat exchanger 8 via the second four-way valve 4 and is evaporated and absorbs heat in the indoor heat exchanger 8. . Indoor cooling is performed by this heat absorption. The evaporated refrigerant is sucked into the compressor 1 through the first four-way valve 2.

Next, the heating operation mode using the outdoor heat exchanger 3 as an evaporator and the indoor heat exchanger 8 as a radiator will be described. The refrigerant flow in the heating operation mode is indicated by a wavy arrow in the figure.
The refrigerant in the heating operation mode is compressed and discharged at a high temperature and a high pressure by the compressor 1 driven by the motor 12, guided to the auxiliary compressor 10, and further pressurized (expressor) by the auxiliary compressor 10. It passes through the first four-way valve 2 and is introduced into the indoor heat exchanger 8. In the indoor heat exchanger 8, since the CO ₂ refrigerant is in a supercritical state, it does not enter a gas-liquid two-phase state, but dissipates heat to an external fluid such as air or water. Heating is performed. Thereafter, the CO ₂ refrigerant is introduced into the pre-expansion valve 5, the expander 6, and the sub-expander 21, and decompressed by the pre-expansion valve 5, the expander 6, and the sub-expander 21. The power recovered by the expander 6 during this decompression is used to drive the auxiliary compressor 10. At this time, for example, the optimum refrigerant amount flowing into the expander 6 is calculated from the high-pressure refrigerant temperature and the high-pressure refrigerant pressure detected at the outlet side of the indoor heat exchanger 8, the refrigerant evaporation pressure, the rotation speed of the compressor 1, and the like. When the refrigerant flow rate is smaller than the optimum refrigerant amount, the opening amount of the adjustment valve 7 is increased to increase the refrigerant amount flowing to the injection circuit 20, thereby increasing the refrigerant flow rate per expansion process of the expander 6. On the other hand, when the refrigerant flow rate is larger than the calculated optimum refrigerant amount, the opening degree of the pre-expansion valve 5 is reduced to reduce the refrigerant flow rate flowing into the inlet of the expander 6.

The CO ₂ refrigerant decompressed by the pre-expansion valve 5 and the expander 6 is guided to the outdoor heat exchanger 3 via the second four-way valve 4 and is evaporated and absorbs heat in the outdoor heat exchanger 3. The evaporated refrigerant is sucked into the compressor 1 via the first four-way valve 2.
As described above, according to the present embodiment, by controlling the amount of refrigerant from the injection circuit 20, the refrigerant flow rate at the outlet of the expander 6 can be adjusted, while the opening degree of the pre-expansion valve 5 is changed. By adjusting the inlet pressure of the expander 6, the amount of refrigerant flowing through the expander 6 can be controlled. Therefore, power recovery can be performed efficiently in the expander 6.

Hereinafter, a refrigeration cycle apparatus according to another embodiment of the present invention will be described with respect to a heat pump type air conditioning apparatus with reference to the drawings.
FIG. 9 is a configuration diagram of a heat pump air-conditioning type air conditioner according to the present embodiment.
As shown in the figure, the heat pump air-conditioning type air conditioner according to this example uses a CO ₂ refrigerant as a refrigerant, a compressor 1 having a motor 12, an auxiliary compressor 10, an outdoor heat exchanger 3, It is comprised from the refrigerant circuit which connected the expander 6 and the indoor side heat exchanger 8 with piping.
A sub expander 23 is provided on the inflow side of the expander 6, and a generator 24 is connected to a drive shaft of the sub expander 23.
In addition, the refrigerant circuit is provided with an injection circuit 20 that introduces high-pressure refrigerant on the outlet side of the outdoor heat exchanger 3 in the middle of the expansion process of the expander 6, and the injection circuit 20 flows through the injection circuit 20. An adjustment valve 7 for adjusting the amount of refrigerant is provided.
Further, the drive shaft of the expander 6 and the drive shaft of the auxiliary compressor 10 are connected, and the auxiliary compressor 10 is driven by the power recovered by the expander 6.
The refrigerant circuit includes a first four-way valve 2 to which a suction side pipe of the compressor 1 and a discharge side pipe of the auxiliary compressor 10 are connected, a suction side pipe of the sub expander 23, and a discharge side of the expander 6. A second four-way valve 4 to which an injection circuit 20 is connected as well as a pipe is provided.

The operation of the heat pump type air conditioning apparatus according to this embodiment will be described below.
First, the cooling operation mode using the outdoor heat exchanger 3 as a radiator and the indoor heat exchanger 8 as an evaporator will be described. The refrigerant flow in the cooling operation mode is indicated by solid line arrows in the figure.
The refrigerant in the cooling operation mode is compressed and discharged at a high temperature and high pressure by the compressor 1 driven by the motor 12, guided to the auxiliary compressor 10, and further boosted (expressor) by the auxiliary compressor 10. It is introduced into the outdoor heat exchanger 3 via the first four-way valve 2. In the outdoor heat exchanger 3, since the CO ₂ refrigerant is in a supercritical state, it does not enter a gas-liquid two-phase state but radiates heat to an external fluid such as air or water. Thereafter, the CO ₂ refrigerant is introduced into the sub-expander 23 and the expander 6 and decompressed by the sub-expander 23 and the expander 6. The power recovered by the expander 6 during this decompression is used to drive the auxiliary compressor 10. At this time, for example, the optimum refrigerant amount flowing into the expander 6 is calculated from the high-pressure refrigerant temperature and high-pressure refrigerant pressure detected at the outlet side of the outdoor heat exchanger 3, the refrigerant evaporation pressure, the rotation speed of the compressor 1, and the like. When the refrigerant flow rate is smaller than the optimum refrigerant amount, the opening amount of the adjusting valve 7 is increased to increase the refrigerant amount flowing through the injection circuit 20, thereby increasing the refrigerant flow rate per expansion process of the expander 6. On the other hand, when the refrigerant flow rate is larger than the calculated optimum refrigerant amount, the torque (generator load) of the generator 24 is increased to reduce the refrigerant flow rate flowing into the inlet of the expander 6.
The CO ₂ refrigerant decompressed by the sub-expander 23 and the expander 6 is guided to the indoor heat exchanger 8 via the second four-way valve 4 and is evaporated and absorbs heat in the indoor heat exchanger 8. . Indoor cooling is performed by this heat absorption. The evaporated refrigerant is sucked into the compressor 1 through the first four-way valve 2.

Next, the heating operation mode using the outdoor heat exchanger 3 as an evaporator and the indoor heat exchanger 8 as a radiator will be described. The refrigerant flow in the heating operation mode is indicated by a wavy arrow in the figure.
The refrigerant in the heating operation mode is compressed and discharged at a high temperature and a high pressure by the compressor 1 driven by the motor 12, guided to the auxiliary compressor 10, and further pressurized (expressor) by the auxiliary compressor 10. It passes through the first four-way valve 2 and is introduced into the indoor heat exchanger 8. In the indoor heat exchanger 8, since the CO ₂ refrigerant is in a supercritical state, it does not enter a gas-liquid two-phase state, but dissipates heat to an external fluid such as air or water. Heating is performed. Thereafter, the CO ₂ refrigerant is introduced into the sub-expander 23 and the expander 6 and decompressed by the sub-expander 23 and the expander 6. The power recovered by the expander 6 during this decompression is used to drive the auxiliary compressor 10. At this time, for example, the optimum refrigerant amount flowing into the expander 6 is calculated from the high-pressure refrigerant temperature and the high-pressure refrigerant pressure detected at the outlet side of the indoor heat exchanger 8, the refrigerant evaporation pressure, the rotation speed of the compressor 1, and the like. When the refrigerant flow rate is smaller than the optimum refrigerant amount, the opening amount of the adjustment valve 7 is increased to increase the refrigerant amount flowing to the injection circuit 20, thereby increasing the refrigerant flow rate per expansion process of the expander 6. On the other hand, when the refrigerant flow rate is larger than the calculated optimum refrigerant amount, the torque (generator load) of the generator 24 is increased to reduce the refrigerant flow rate flowing into the inlet of the expander 6.
The CO ₂ refrigerant decompressed by the sub-expander 23 and the expander 6 is guided to the outdoor heat exchanger 3 via the second four-way valve 4 and is evaporated and absorbs heat in the outdoor heat exchanger 3. The evaporated refrigerant is sucked into the compressor 1 via the first four-way valve 2.
As described above, according to this embodiment, by controlling the amount of refrigerant from the injection circuit 20, the refrigerant flow rate at the outlet of the expander 6 can be adjusted, while the generator connected to the sub expander 23. The amount of refrigerant flowing through the expander 6 can be controlled by adjusting the inlet pressure of the expander 6 by changing the torque of 24 (that is, the load of the generator). Therefore, power can be recovered efficiently in the expander 6, and higher power can be recovered from the refrigeration cycle by using the power recovered from the sub-expander 23 for power generation by the generator 24.

Hereinafter, a refrigeration cycle apparatus according to another embodiment of the present invention will be described with respect to a heat pump type air conditioning apparatus with reference to the drawings.
FIG. 10 is a configuration diagram of a heat pump type air conditioning apparatus according to the present embodiment.
As shown in the figure, the heat pump air-conditioning type air conditioner according to this embodiment uses a CO ₂ refrigerant as a refrigerant, a compressor 1 having a motor 12, an auxiliary compressor 10, an outdoor heat exchanger 3, and the like. The expander 6 and the indoor heat exchanger 8 are configured by a refrigerant circuit connected by piping.
A sub expander 23 is provided on the discharge side of the expander 6, and a generator 24 is connected to the drive shaft of the sub expander 23.
In addition, the refrigerant circuit is provided with an injection circuit 20 that introduces high-pressure refrigerant on the outlet side of the outdoor heat exchanger 3 in the middle of the expansion process of the expander 6, and the injection circuit 20 flows through the injection circuit 20. An adjustment valve 7 for adjusting the amount of refrigerant is provided.
Further, the drive shaft of the expander 6 and the drive shaft of the auxiliary compressor 10 are connected, and the auxiliary compressor 10 is driven by the power recovered by the expander 6.
The refrigerant circuit includes a first four-way valve 2 to which a suction side pipe of the compressor 1 and a discharge side pipe of the auxiliary compressor 10 are connected, a discharge side pipe of the sub expander 23 and an inflow side of the expander 6. A second four-way valve 4 to which a pipe is connected and an injection circuit 20 is connected is provided.

The operation of the heat pump type air conditioning apparatus according to this embodiment will be described below.
First, the cooling operation mode using the outdoor heat exchanger 3 as a radiator and the indoor heat exchanger 8 as an evaporator will be described. The refrigerant flow in the cooling operation mode is indicated by solid line arrows in the figure.
The refrigerant in the cooling operation mode is compressed and discharged at a high temperature and high pressure by the compressor 1 driven by the motor 12, guided to the auxiliary compressor 10, and further boosted (expressor) by the auxiliary compressor 10. It is introduced into the outdoor heat exchanger 3 via the first four-way valve 2. In the outdoor heat exchanger 3, since the CO ₂ refrigerant is in a supercritical state, it does not enter a gas-liquid two-phase state but radiates heat to an external fluid such as air or water. Thereafter, the CO ₂ refrigerant is introduced into the expander 6 and the sub-expander 23 and decompressed by the expander 6 and the sub-expander 23. The power recovered by the expander 6 during this decompression is used to drive the auxiliary compressor 10. At this time, for example, the optimum refrigerant amount flowing into the expander 6 is calculated from the high-pressure refrigerant temperature and high-pressure refrigerant pressure detected at the outlet side of the outdoor heat exchanger 3, the refrigerant evaporation pressure, the rotation speed of the compressor 1, and the like. When the refrigerant flow rate is smaller than the optimum refrigerant amount, the opening amount of the adjusting valve 7 is increased to increase the refrigerant amount flowing through the injection circuit 20, thereby increasing the refrigerant flow rate per expansion process of the expander 6. In this case, the torque (generator load) of the generator 24 is minimized. On the other hand, when the refrigerant flow rate is larger than the calculated optimum refrigerant amount, the regulator valve 7 is closed, and the generator 24 is connected to the sub-expander 23 side to reduce the low-pressure side pressure and flow into the inlet of the expander 6. Reduce the refrigerant flow rate.
The CO ₂ refrigerant decompressed by the sub-expander 23 and the expander 6 is guided to the indoor heat exchanger 8 via the second four-way valve 4 and is evaporated and absorbs heat in the indoor heat exchanger 8. . Indoor cooling is performed by this heat absorption. The evaporated refrigerant is sucked into the compressor 1 through the first four-way valve 2.

Next, the heating operation mode using the outdoor heat exchanger 3 as an evaporator and the indoor heat exchanger 8 as a radiator will be described. The refrigerant flow in the heating operation mode is indicated by a wavy arrow in the figure.
The refrigerant in the heating operation mode is compressed and discharged at a high temperature and a high pressure by the compressor 1 driven by the motor 12, guided to the auxiliary compressor 10, and further pressurized (expressor) by the auxiliary compressor 10. It passes through the first four-way valve 2 and is introduced into the indoor heat exchanger 8. In the indoor heat exchanger 8, since the CO ₂ refrigerant is in a supercritical state, it does not enter a gas-liquid two-phase state, but dissipates heat to an external fluid such as air or water. Heating is performed. Thereafter, the CO ₂ refrigerant is introduced into the expander 6 and the sub-expander 23 and decompressed by the expander 6 and the sub-expander 23. The power recovered by the expander 6 during this decompression is used to drive the auxiliary compressor 10. At this time, for example, the optimum refrigerant amount flowing into the expander 6 is calculated from the high-pressure refrigerant temperature and the high-pressure refrigerant pressure detected at the outlet side of the indoor heat exchanger 8, the refrigerant evaporation pressure, the rotation speed of the compressor 1, and the like. When the refrigerant flow rate is smaller than the optimum refrigerant amount, the opening amount of the adjustment valve 7 is increased to increase the refrigerant amount flowing to the injection circuit 20, thereby increasing the refrigerant flow rate per expansion process of the expander 6. In this case, the torque (generator load) of the generator 24 is minimized. On the other hand, when the refrigerant flow rate is larger than the calculated optimum refrigerant amount, the adjustment valve 7 is closed, and the torque (generator load) of the generator 24 is increased to reduce the refrigerant flow rate flowing into the inlet of the expander 6.
The CO ₂ refrigerant decompressed by the sub-expander 23 and the expander 6 is guided to the outdoor heat exchanger 3 via the second four-way valve 4 and is evaporated and absorbs heat in the outdoor heat exchanger 3. The evaporated refrigerant is sucked into the compressor 1 via the first four-way valve 2.
As described above, according to this embodiment, by controlling the amount of refrigerant from the injection circuit 20, the refrigerant flow rate at the outlet of the expander 6 can be adjusted, while the adjustment valve 7 is closed and the sub-expander is closed. The amount of refrigerant flowing through the expander 6 can be controlled by adjusting the pressure at the outlet of the expander 6 by changing the torque of the generator 24 connected to the generator 23 (that is, the load of the generator). Therefore, power can be recovered efficiently in the expander 6, and higher power can be recovered from the refrigeration cycle by using the power recovered from the sub-expander 23 for power generation by the generator 24.

Hereinafter, a refrigeration cycle apparatus according to another embodiment of the present invention will be described with respect to a heat pump type air conditioning apparatus with reference to the drawings.
FIG. 11 is a configuration diagram of a heat pump air-conditioning type air conditioner according to the present embodiment.
As shown in the figure, the heat pump air-conditioning type air conditioner according to the present embodiment uses a CO ₂ refrigerant as a refrigerant, a compressor 1 having a motor 12, an outdoor heat exchanger 3, an expander 6, It is comprised from the refrigerant circuit which connected the indoor side heat exchanger 8 and the auxiliary compressor 10 with piping.
A pre-expansion valve 5 is provided on the inflow side of the expander 6.
In addition, the refrigerant circuit is provided with an injection circuit 20 that introduces high-pressure refrigerant on the outlet side of the outdoor heat exchanger 3 in the middle of the expansion process of the expander 6, and the injection circuit 20 flows through the injection circuit 20. An adjustment valve 7 for adjusting the amount of refrigerant is provided.
Further, the drive shaft of the expander 6 and the drive shaft of the auxiliary compressor 10 are connected, and the auxiliary compressor 10 is driven by the power recovered by the expander 6.
The refrigerant circuit is connected to the first four-way valve 2 to which the discharge side pipe and the suction side pipe of the compressor 1 are connected, and to the injection circuit 20 and to the discharge side pipe and the suction side pipe of the expander 6. Are connected to each other, and a third four-way valve 9 to which the discharge side pipe and the suction side pipe of the auxiliary compressor 10 are connected. In the case of a refrigerant flow in which the outdoor heat exchanger 3 is a radiator and the indoor heat exchanger 8 is an evaporator, the discharge of the auxiliary compressor 10 is performed by switching between the first four-way valve 2 and the third four-way valve 9. The side is configured to be the suction side of the compressor 1. In the case of a refrigerant flow in which the outdoor heat exchanger 3 is an evaporator and the indoor heat exchanger 8 is a radiator, the compressor 1 is switched by switching between the first four-way valve 2 and the third four-way valve 9. The discharge side is configured to be the suction side of the auxiliary compressor 10. Moreover, it is comprised so that the refrigerant | coolant direction which flows through the expander 6 may always become the same direction by switching of the 2nd four-way valve 4. FIG.

The operation of the heat pump type air conditioning apparatus according to this embodiment will be described below.
First, the cooling operation mode using the outdoor heat exchanger 3 as a radiator and the indoor heat exchanger 8 as an evaporator will be described. The refrigerant flow in the cooling operation mode is indicated by solid line arrows in the figure.
The refrigerant in the cooling operation mode is compressed and discharged at a high temperature and a high pressure by the compressor 1 driven by the motor 12, and is introduced into the outdoor heat exchanger 3 through the first four-way valve 2. In the outdoor heat exchanger 3, since the CO ₂ refrigerant is in a supercritical state, it does not enter a gas-liquid two-phase state but radiates heat to an external fluid such as air or water. Thereafter, the CO ₂ refrigerant is introduced into the pre-expansion valve 5, the expander 6, and the sub-expander 21, and decompressed by the pre-expansion valve 5, the expander 6, and the sub-expander 21. The power recovered by the expander 6 during this decompression is used to drive the auxiliary compressor 10. At this time, for example, the optimum refrigerant amount flowing into the expander 6 is calculated from the high-pressure refrigerant temperature and high-pressure refrigerant pressure detected at the outlet side of the outdoor heat exchanger 3, the refrigerant evaporation pressure, the rotation speed of the compressor 1, and the like. When the refrigerant flow rate is smaller than the optimum refrigerant amount, the opening amount of the adjusting valve 7 is increased to increase the refrigerant amount flowing through the injection circuit 20, thereby increasing the refrigerant flow rate per expansion process of the expander 6. On the other hand, when the refrigerant flow rate is larger than the calculated optimum refrigerant amount, the opening degree of the pre-expansion valve 5 is reduced to reduce the refrigerant flow rate flowing into the inlet of the expander 6.
The CO ₂ refrigerant depressurized by the pre-expansion valve 5 and the expander 6 is guided to the indoor heat exchanger 8 via the second four-way valve 4 and is evaporated and absorbs heat in the indoor heat exchanger 8. . Indoor cooling is performed by this heat absorption. The evaporated refrigerant is guided to the auxiliary compressor 10 through the second four-way valve 9, supercharged (charged) by the auxiliary compressor 10, and sucked into the compressor 1.

Next, the heating operation mode using the outdoor heat exchanger 3 as an evaporator and the indoor heat exchanger 8 as a radiator will be described. The refrigerant flow in the heating operation mode is indicated by a wavy arrow in the figure.
The refrigerant in the heating operation mode is compressed and discharged at a high temperature and a high pressure by the compressor 1 driven by the motor 12, and is guided to the auxiliary compressor 10 through the first four-way valve 2 and the third four-way valve 9 to assist. The pressure is further increased (expressor) by the compressor 10. The refrigerant whose pressure has been increased by the auxiliary compressor 10 is introduced into the indoor heat exchanger 8 through the third four-way valve 9. In the indoor heat exchanger 8, since the CO ₂ refrigerant is in a supercritical state, it does not enter a gas-liquid two-phase state, but dissipates heat to an external fluid such as air or water. Heating is performed. Thereafter, the CO ₂ refrigerant is introduced into the pre-expansion valve 5, the expander 6, and the sub-expander 21, and decompressed by the pre-expansion valve 5, the expander 6, and the sub-expander 21. The power recovered by the expander 6 during this decompression is used to drive the auxiliary compressor 10. At this time, for example, the optimum refrigerant amount flowing into the expander 6 is calculated from the high-pressure refrigerant temperature and the high-pressure refrigerant pressure detected at the outlet side of the indoor heat exchanger 8, the refrigerant evaporation pressure, the rotation speed of the compressor 1, and the like. When the refrigerant flow rate is smaller than the optimum refrigerant amount, the opening amount of the adjustment valve 7 is increased to increase the refrigerant amount flowing to the injection circuit 20, thereby increasing the refrigerant flow rate per expansion process of the expander 6. On the other hand, when the refrigerant flow rate is larger than the calculated optimum refrigerant amount, the opening degree of the pre-expansion valve 5 is reduced to reduce the refrigerant flow rate flowing into the inlet of the expander 6.
The CO ₂ refrigerant decompressed by the pre-expansion valve 5 and the expander 6 is guided to the outdoor heat exchanger 3 via the second four-way valve 4 and is evaporated and absorbs heat in the outdoor heat exchanger 3. The evaporated refrigerant is sucked into the compressor 1 via the first four-way valve 2.
As described above, according to the present embodiment, by controlling the amount of refrigerant from the injection circuit 20, the refrigerant flow rate at the outlet of the expander 6 can be adjusted, while the opening degree of the pre-expansion valve 5 is changed. By adjusting the inlet pressure of the expander 6, the amount of refrigerant flowing through the expander 6 can be controlled. Therefore, power can be recovered efficiently in the expander 6 and higher power can be recovered from the refrigeration cycle by using the power recovered from the sub expander 21 for power generation by the generator 22.
Further, according to the present embodiment, the compressor 1 that compresses the refrigerant, the expander 6 that recovers power, and the auxiliary compressor 10 are installed separately, and supercharged (charger) by the auxiliary compressor 10 in the cooling operation mode. The expander 6 can be operated as a charger-type expander suitable for cooling by the configuration in which the refrigeration cycle is switched so as to perform pressure increase (expressor) in the heating operation mode. It can also be operated as a type of expander.

Hereinafter, a refrigeration cycle apparatus according to another embodiment of the present invention will be described with respect to a heat pump type air conditioning apparatus with reference to the drawings.
FIG. 12 is a configuration diagram of the heat pump air-conditioning type air conditioner according to the present embodiment.
As shown in the figure, the heat pump air-conditioning type air conditioner according to the present embodiment uses a CO ₂ refrigerant as a refrigerant, a compressor 1 having a motor 12, an outdoor heat exchanger 3, an expander 6, It is comprised from the refrigerant circuit which connected the indoor side heat exchanger 8 and the auxiliary compressor 10 with piping.
A sub expander 23 is provided on the inflow side of the expander 6, and a generator 24 is connected to a drive shaft of the sub expander 23.
In addition, the refrigerant circuit is provided with an injection circuit 20 that introduces high-pressure refrigerant on the outlet side of the outdoor heat exchanger 3 in the middle of the expansion process of the expander 6, and the injection circuit 20 flows through the injection circuit 20. An adjustment valve 7 for adjusting the amount of refrigerant is provided.
Further, the drive shaft of the expander 6 and the drive shaft of the auxiliary compressor 10 are connected, and the auxiliary compressor 10 is driven by the power recovered by the expander 6.
The refrigerant circuit is connected to the first four-way valve 2 to which the discharge side pipe and the suction side pipe of the compressor 1 are connected, and to the injection circuit 20 and to the discharge side pipe and the suction side pipe of the expander 6. Are connected to each other, and a third four-way valve 9 to which the discharge side pipe and the suction side pipe of the auxiliary compressor 10 are connected. In the case of a refrigerant flow in which the outdoor heat exchanger 3 is a radiator and the indoor heat exchanger 8 is an evaporator, the discharge of the auxiliary compressor 10 is performed by switching between the first four-way valve 2 and the third four-way valve 9. The side is configured to be the suction side of the compressor 1. In the case of a refrigerant flow in which the outdoor heat exchanger 3 is an evaporator and the indoor heat exchanger 8 is a radiator, the compressor 1 is switched by switching between the first four-way valve 2 and the third four-way valve 9. The discharge side is configured to be the suction side of the auxiliary compressor 10. Moreover, it is comprised so that the refrigerant | coolant direction which flows through the expander 6 may always become the same direction by switching of the 2nd four-way valve 4. FIG.

The operation of the heat pump type air conditioning apparatus according to this embodiment will be described below.
First, the cooling operation mode using the outdoor heat exchanger 3 as a radiator and the indoor heat exchanger 8 as an evaporator will be described. The refrigerant flow in the cooling operation mode is indicated by solid line arrows in the figure.
The refrigerant in the cooling operation mode is compressed and discharged at a high temperature and a high pressure by the compressor 1 driven by the motor 12, and is introduced into the outdoor heat exchanger 3 through the first four-way valve 2. In the outdoor heat exchanger 3, since the CO ₂ refrigerant is in a supercritical state, it does not enter a gas-liquid two-phase state but radiates heat to an external fluid such as air or water. Thereafter, the CO ₂ refrigerant is introduced into the sub-expander 23 and the expander 6 and decompressed by the sub-expander 23 and the expander 6. The power recovered by the expander 6 during this decompression is used to drive the auxiliary compressor 10. At this time, for example, the optimum refrigerant amount flowing into the expander 6 is calculated from the high-pressure refrigerant temperature, the high-pressure refrigerant pressure, the refrigerant evaporating pressure, the rotation speed of the compressor 1 and the like detected on the outlet side of the outdoor heat exchanger 3, and calculated. When the refrigerant flow rate is smaller than the optimum refrigerant amount, the opening amount of the adjusting valve 7 is increased to increase the refrigerant amount flowing through the injection circuit 20, thereby increasing the refrigerant flow rate per expansion process of the expander 6. On the other hand, when the refrigerant flow rate is larger than the calculated optimum refrigerant amount, the torque (generator load) of the generator 24 is increased to reduce the refrigerant flow rate flowing into the inlet of the expander 6.
The CO ₂ refrigerant decompressed by the sub-expander 23 and the expander 6 is guided to the indoor heat exchanger 8 via the second four-way valve 4 and is evaporated and absorbs heat in the indoor heat exchanger 8. . Indoor cooling is performed by this heat absorption. The evaporated refrigerant is guided to the auxiliary compressor 10 through the second four-way valve 9, supercharged (charged) by the auxiliary compressor 10, and sucked into the compressor 1.

Next, a heating operation mode using the outdoor heat exchanger 3 as an evaporator and the indoor heat exchanger 8 as a radiator will be described. The refrigerant flow in the heating operation mode is indicated by a wavy arrow in the figure.
The refrigerant in the heating operation mode is compressed and discharged at a high temperature and high pressure by the compressor 1 driven by the motor 12, and is guided to the auxiliary compressor 10 through the first four-way valve 2 and the third four-way valve 9 to assist. The pressure is further increased (expressor) by the compressor 10. The refrigerant whose pressure has been increased by the auxiliary compressor 10 is introduced into the indoor heat exchanger 8 via the third four-way valve 9. In the indoor heat exchanger 8, since the CO ₂ refrigerant is in a supercritical state, the CO ₂ refrigerant does not enter a gas-liquid two-phase state, but dissipates heat to an external fluid such as air or water. Heating is performed. Thereafter, the CO ₂ refrigerant is introduced into the sub-expander 23 and the expander 6 and decompressed by the sub-expander 23 and the expander 6. The power recovered by the expander 6 during this decompression is used to drive the auxiliary compressor 10. At this time, for example, the optimum refrigerant amount flowing into the expander 6 is calculated from the high-pressure refrigerant temperature and the high-pressure refrigerant pressure detected at the outlet side of the indoor heat exchanger 8, the refrigerant evaporating pressure, the rotation speed of the compressor 1, and the like. When the refrigerant flow rate is smaller than the optimum refrigerant amount, the opening amount of the adjusting valve 7 is increased to increase the refrigerant amount flowing through the injection circuit 20, thereby increasing the refrigerant flow rate per expansion process of the expander 6. On the other hand, when the refrigerant flow rate is larger than the calculated optimum refrigerant amount, the torque (generator load) of the generator 24 is increased to reduce the refrigerant flow rate flowing into the inlet of the expander 6.
The CO ₂ refrigerant decompressed by the sub-expander 23 and the expander 6 is guided to the outdoor heat exchanger 3 via the second four-way valve 4 and is evaporated and absorbs heat in the outdoor heat exchanger 3. The evaporated refrigerant is sucked into the compressor 1 via the first four-way valve 2.
As described above, according to this embodiment, by controlling the amount of refrigerant from the injection circuit 20, the refrigerant flow rate at the outlet of the expander 6 can be adjusted, while the generator connected to the sub expander 23. The amount of refrigerant flowing through the expander 6 can be controlled by adjusting the inlet pressure of the expander 6 by changing the torque of 24 (that is, the load of the generator). Therefore, power can be recovered efficiently in the expander 6, and higher power can be recovered from the refrigeration cycle by using the power recovered from the sub-expander 23 for power generation by the generator 24.
Further, according to the present embodiment, the compressor 1 that compresses the refrigerant, the expander 6 that recovers power, and the auxiliary compressor 10 are installed separately, and supercharged (charger) by the auxiliary compressor 10 in the cooling operation mode. The expander 6 can be operated as a charger-type expander suitable for cooling by the configuration in which the refrigeration cycle is switched so as to perform pressure increase (expressor) in the heating operation mode. It can also be operated as a type of expander.

Hereinafter, a refrigeration cycle apparatus according to another embodiment of the present invention will be described with reference to the drawings for a heat pump type air conditioning apparatus.
FIG. 13 is a configuration diagram of a heat pump type air conditioning apparatus according to the present embodiment.
As shown in the figure, the heat pump air-conditioning type air conditioner according to this example uses a CO ₂ refrigerant as a refrigerant, a compressor 1 having a motor 12, an outdoor heat exchanger 3, an expander 6, It is comprised from the refrigerant circuit which connected the indoor side heat exchanger 8 and the auxiliary compressor 10 with piping.
A sub expander 23 is provided on the discharge side of the expander 6, and a generator 24 is connected to the drive shaft of the sub expander 23.
The refrigerant circuit is provided with an injection circuit 20 for introducing high-pressure refrigerant on the outlet side of the outdoor heat exchanger 3 in the middle of the expansion process of the expander 6. The injection circuit 20 flows through the injection circuit 20. An adjustment valve 7 for adjusting the amount of refrigerant is provided.
Further, the drive shaft of the expander 6 and the drive shaft of the auxiliary compressor 10 are connected, and the auxiliary compressor 10 is driven by the power recovered by the expander 6.
The refrigerant circuit is connected to the first four-way valve 2 to which the discharge side pipe and the suction side pipe of the compressor 1 are connected, and to the injection circuit 20 and to the discharge side pipe and the suction side pipe of the expander 6. Are connected to each other, and a third four-way valve 9 to which the discharge side pipe and the suction side pipe of the auxiliary compressor 10 are connected. In the case of a refrigerant flow in which the outdoor heat exchanger 3 is a radiator and the indoor heat exchanger 8 is an evaporator, the discharge of the auxiliary compressor 10 is performed by switching between the first four-way valve 2 and the third four-way valve 9. The side is configured to be the suction side of the compressor 1. In the case of a refrigerant flow in which the outdoor heat exchanger 3 is an evaporator and the indoor heat exchanger 8 is a radiator, the compressor 1 is switched by switching between the first four-way valve 2 and the third four-way valve 9. The discharge side is configured to be the suction side of the auxiliary compressor 10. Further, the direction of the refrigerant flowing through the expander 6 is always set to the same direction by switching the second four-way valve 4.

The operation of the heat pump type air conditioning apparatus according to this embodiment will be described below.
First, the cooling operation mode using the outdoor heat exchanger 3 as a radiator and the indoor heat exchanger 8 as an evaporator will be described. The refrigerant flow in the cooling operation mode is indicated by solid line arrows in the figure.
The refrigerant in the cooling operation mode is compressed and discharged at a high temperature and a high pressure by the compressor 1 driven by the motor 12, and is introduced into the outdoor heat exchanger 3 through the first four-way valve 2. In the outdoor heat exchanger 3, since the CO ₂ refrigerant is in a supercritical state, it does not enter a gas-liquid two-phase state but radiates heat to an external fluid such as air or water. Thereafter, the CO ₂ refrigerant is introduced into the expander 6 and the sub-expander 23 and decompressed by the expander 6 and the sub-expander 23. The power recovered by the expander 6 during this decompression is used to drive the auxiliary compressor 10. At this time, for example, the optimum refrigerant amount flowing into the expander 6 is calculated from the high-pressure refrigerant temperature and high-pressure refrigerant pressure detected at the outlet side of the outdoor heat exchanger 3, the refrigerant evaporating pressure, the rotation speed of the compressor 1, and the like. When the refrigerant flow rate is smaller than the optimum refrigerant amount, the opening amount of the adjustment valve 7 is increased to increase the refrigerant amount flowing to the injection circuit 20, thereby increasing the refrigerant flow rate per expansion process of the expander 6. In this case, the torque (generator load) of the generator 24 is minimized. On the other hand, when the refrigerant flow rate is larger than the calculated optimum refrigerant amount, the adjustment valve 7 is closed, and the torque (generator load) of the generator 24 is increased to reduce the refrigerant flow rate flowing into the inlet of the expander 6.
The CO ₂ refrigerant decompressed by the sub-expander 23 and the expander 6 is guided to the indoor heat exchanger 8 via the second four-way valve 4 and is evaporated and absorbs heat in the indoor heat exchanger 8. . Indoor cooling is performed by this heat absorption. The evaporated refrigerant is guided to the auxiliary compressor 10 through the second four-way valve 9, supercharged (charged) by the auxiliary compressor 10, and sucked into the compressor 1.

Next, the heating operation mode using the outdoor heat exchanger 3 as an evaporator and the indoor heat exchanger 8 as a radiator will be described. The refrigerant flow in the heating operation mode is indicated by a wavy arrow in the figure.
The refrigerant in the heating operation mode is compressed and discharged at a high temperature and a high pressure by the compressor 1 driven by the motor 12, and is guided to the auxiliary compressor 10 through the first four-way valve 2 and the third four-way valve 9 to assist. The pressure is further increased (expressor) by the compressor 10. The refrigerant whose pressure has been increased by the auxiliary compressor 10 is introduced into the indoor heat exchanger 8 through the third four-way valve 9. In the indoor heat exchanger 8, since the CO ₂ refrigerant is in a supercritical state, it does not enter a gas-liquid two-phase state, but dissipates heat to an external fluid such as air or water. Heating is performed. Thereafter, the CO ₂ refrigerant is introduced into the expander 6 and the sub-expander 23 and decompressed by the expander 6 and the sub-expander 23. The power recovered by the expander 6 during this decompression is used to drive the auxiliary compressor 10. At this time, for example, the optimum refrigerant amount flowing into the expander 6 is calculated from the high-pressure refrigerant temperature and the high-pressure refrigerant pressure detected at the outlet side of the indoor heat exchanger 8, the refrigerant evaporation pressure, the rotation speed of the compressor 1, and the like. When the refrigerant flow rate is smaller than the optimum refrigerant amount, the opening amount of the adjustment valve 7 is increased to increase the refrigerant amount flowing to the injection circuit 20, thereby increasing the refrigerant flow rate per expansion process of the expander 6. In this case, the torque (generator load) of the generator 24 is minimized. On the other hand, when the refrigerant flow rate is larger than the calculated optimum refrigerant amount, the adjustment valve 7 is closed, and the torque (generator load) of the generator 24 is increased to reduce the refrigerant flow rate flowing into the inlet of the expander 6.
The CO ₂ refrigerant decompressed by the sub-expander 23 and the expander 6 is guided to the outdoor heat exchanger 3 via the second four-way valve 4 and is evaporated and absorbs heat in the outdoor heat exchanger 3. The evaporated refrigerant is sucked into the compressor 1 via the first four-way valve 2.
As described above, according to the present embodiment, the refrigerant flow rate at the inlet of the expander 6 can be adjusted by controlling the refrigerant amount from the injection circuit 20, while the adjustment valve 7 is closed and the sub-expander is closed. The amount of refrigerant flowing through the expander 6 can be controlled by adjusting the outlet pressure of the expander 6 by changing the torque of the generator 24 connected to the load 23 (that is, the load of the generator). Therefore, power recovery can be efficiently performed in the expander 6 and higher power recovery can be performed from the refrigeration cycle by using the power recovered from the sub expander 21 or the sub expander 23 for power generation by the generator 24. be able to.
Further, according to the present embodiment, the compressor 1 that compresses the refrigerant, the expander 6 that recovers power, and the auxiliary compressor 10 are installed separately, and supercharged (charger) by the auxiliary compressor 10 in the cooling operation mode. The expander 6 can be operated as a charger-type expander suitable for cooling by the configuration in which the refrigeration cycle is switched so as to perform pressure increase (expressor) in the heating operation mode. It can also be operated as a type of expander.

  In the said Example, although demonstrated using the heat pump type air-conditioning type air conditioning apparatus, the outdoor side heat exchanger 3 was made into the 1st heat exchanger, the indoor side heat exchanger 8 was made into the 2nd heat exchanger, and these 1st The other refrigeration cycle apparatus using the heat exchanger 1 or the second heat exchanger for a hot / cold water heater or a regenerator may be used.

1 is a block diagram of a heat pump type air conditioning apparatus according to an embodiment of the present invention. The block diagram of the heat pump type air conditioning air conditioner by other Example of this invention The block diagram of the heat pump type air conditioning air conditioner by other Example of this invention The block diagram of the heat pump type air conditioning air conditioner by other Example of this invention The block diagram of the heat pump type air conditioning air conditioner by other Example of this invention The block diagram of the heat pump type air conditioning air conditioner by other Example of this invention The block diagram of the heat pump type air conditioning air conditioner by other Example of this invention The block diagram of the heat pump type air conditioning air conditioner by other Example of this invention The block diagram of the heat pump type air conditioning air conditioner by other Example of this invention The block diagram of the heat pump type air conditioning air conditioner by other Example of this invention The block diagram of the heat pump type air conditioning air conditioner by other Example of this invention The block diagram of the heat pump type air conditioning air conditioner by other Example of this invention The block diagram of the heat pump type air conditioning air conditioner by other Example of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Compressor 2 1st 4 way valve 3 Outdoor heat exchanger 4 2nd 4 way valve 5 Pre-expansion valve 6 Expander 7 Adjustment valve 8 Indoor side heat exchanger 9 3rd 4 way valve 10 Auxiliary compressor 12 Motor 20 Injection circuit

Claims (10)

A refrigeration cycle apparatus that uses carbon dioxide as a refrigerant and includes a compressor, an outdoor heat exchanger, an expander, and an indoor heat exchanger, and introduces high-pressure refrigerant during the expansion process of the expander A refrigeration cycle apparatus provided with an injection circuit. The refrigeration cycle apparatus according to claim 1, further comprising an adjustment valve that adjusts an amount of refrigerant from the injection circuit. The refrigeration cycle apparatus according to claim 1, wherein a pre-expansion valve is provided on a refrigerant inflow side of the expander. The refrigeration cycle apparatus according to claim 1, wherein a sub-expander is provided on the refrigerant inflow side of the expander. The refrigeration cycle apparatus according to claim 1, wherein a sub-expander is provided on the refrigerant outflow side of the expander. The refrigeration cycle apparatus according to claim 4 or 5, wherein a generator is connected to the sub-expander. The refrigeration cycle apparatus according to any one of claims 1 to 5, wherein the power recovered by the expander is used for driving the compressor. An auxiliary compressor is provided on the suction side of the compressor or the discharge side of the compressor, and the power recovered by the expander is used as power for driving the auxiliary compressor instead of the compressor. The refrigeration cycle apparatus according to claim 7. A first four-way valve to which a discharge side pipe and a suction side pipe of the compressor are connected; and a second four-way valve to which a discharge side pipe and a suction side pipe of the expander are connected. The refrigerant discharged from the compressor is selectively flowed to the indoor heat exchanger or the indoor heat exchanger by the valve, and the direction of the refrigerant flowing through the expander by the second four-way valve is always the same direction. The refrigeration cycle apparatus according to any one of claims 1 to 5, wherein A first four-way valve to which a discharge side pipe and a suction side pipe of the compressor and the auxiliary compressor are connected; and a second four-way valve to which a discharge side pipe and a suction side pipe of the expander are connected. The refrigerant discharged from the compressor and the auxiliary compressor is selectively flowed to the indoor heat exchanger or the indoor heat exchanger by the first four-way valve, and the expander is discharged by the second four-way valve. The refrigeration cycle apparatus according to claim 8, wherein the direction of the refrigerant flowing through the sub-expander is always the same.

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