JP2007205595A - Air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the performance and efficiency of an air conditioner composed of a waste heat utilizing circuit utilizing the waste heat of a heat source by a heat exchanger for heating to heat a conditioned room, a refrigerant circuit using a carbon dioxide as a refrigerant and having supercritical pressure at a high-pressure side, and a cascade heat exchanger exchanging heat between the fluid flowing from the heat source to the heat exchanger for heating in the waste heat utilizing circuit, and a refrigerant of the refrigerant circuit. <P>SOLUTION: A refrigerant discharged from a compressor 11 is allowed to flow to the cascade heat exchanger 12, and the refrigerant coming out of the cascade heat exchanger 12 is divided by a flow divider, so that one of the refrigerants flows from an auxiliary expansion valve 15 for heating as an auxiliary pressure reducing device to an auxiliary heat exchanger 17 for heating as an internal heat exchanger to exchange heat with the refrigerant coming out of the cascade heat exchanger 12, and then sucked into a sealed container 30 as an intermediate pressure portion of the compressor 11, and the divided other refrigerant is allowed to flow from the expansion valve 20 for heating as a main pressure reducing device to an outdoor heat exchanger 23 (heat sink), and then sucked to a first compressing element 32 as a low pressure portion of the compressor 11. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention uses a waste heat utilization circuit for utilizing waste heat of a heat source for heating a conditioned room in a heat exchanger for heating, a refrigerant circuit in which carbon dioxide is used as a refrigerant, and a high pressure side is a supercritical pressure, The present invention relates to an air conditioner constructed from a fluid flowing through a waste heat utilization circuit from a heat source to a heating heat exchanger and a cascade heat exchanger that exchanges heat between the refrigerant in the refrigerant circuit.

  Conventionally, this type of air conditioner includes a waste heat utilization circuit for heating waste heat from heat sources such as HEV, FCV car air conditioner and FC cogeneration system in a heat exchanger for heating, and a compressor. A refrigerant circuit including a heat absorber provided outside the room to be conditioned, a decompressor, and a cooling heat exchanger for cooling the room to be conditioned, and ethylene glycol flowing from the heat source to the heating heat exchanger through the waste heat utilization circuit And a cascade heat exchanger that exchanges heat between the fluid and the refrigerant in the refrigerant circuit. The waste heat utilization circuit is provided with a circulation pump, and the fluid is circulated in the waste heat utilization circuit by operating the circulation pump. The fluid flow to the heat source is controlled by a solenoid valve or the like, and when the waste heat of the heat source is used for heating the conditioned room during the heating operation, the fluid flows to the heat source.

  That is, during the heating operation, the conditioned room is heated by flowing a fluid heated by exchanging heat with the heat source to the heating heat exchanger. In addition, before the heat source is heated, such as at the time of startup, the flow of the fluid to the heat source is stopped, and in the cascade heat exchanger, the refrigerant compressed by the compressor and the fluid flowing through the waste heat utilization circuit are heat-exchanged. The fluid is heated, and the heated fluid is passed through the heating heat exchanger to heat the conditioned room. In addition, the refrigerant that has dissipated heat by exchanging heat with the fluid in the cascade heat exchanger is depressurized by the decompression device, and then evaporated by the heat absorber provided outside the chamber to be conditioned. In addition, when cooling the heat source, in addition to the heating in the previous cascade heat exchanger, the heat

  On the other hand, during the cooling operation, after operating the compressor of the refrigerant circuit without operating the circulation pump of the waste heat utilization circuit, the refrigerant radiated by the heat exchanger provided outside is decompressed by the decompression device. The conditioned room was cooled by flowing through a cooling heat exchanger.

  By the way, in recent years, carbon dioxide, which is a natural refrigerant, has been used as a refrigerant in this kind of air conditioner due to global environmental problems. Since carbon dioxide has a favorable characteristic of a warming coefficient of 1, it is attracting attention as an alternative to a fluorocarbon refrigerant. However, the carbon dioxide refrigerant has a critical point of about 7.31 MPa and 31.1 ° C., and the high-pressure side pressure of the refrigerant circuit easily reaches the supercritical region. In particular, if the temperature of the fluid rises due to the cooling circulation of the heat source, the heat exchange capacity between the refrigerant and the fluid decreases, so the temperature after heat release from the refrigerant (cascade heat exchanger outlet) rises, and the cooling and heating capacity decreases accordingly. As a result, there has been a problem that the efficiency is remarkably deteriorated.

In order to eliminate such deterioration in efficiency, a heat exchanger is additionally installed in the refrigerant circuit, and the refrigerant dissipated in the cascade heat exchanger is caused to flow through the heat exchanger, so that the refrigerant and the surrounding air (for example, An apparatus in which the enthalpy difference is increased by further heat dissipating the refrigerant by exchanging heat with the air in the room to be conditioned (Patent Document 1) has been developed.
JP 2002-98430 A

  However, when the temperature of the air (for example, a conditioned room) that exchanges heat with the refrigerant in the heat exchanger rises, the heat dissipation effect cannot be obtained, and the inconvenience that the efficiency is remarkably deteriorated occurs. In addition, the provision of the heat exchanger increases the size of the apparatus and disadvantageously increases the cost.

  The present invention has been made to solve the problems of the related art, and a waste heat utilization circuit for utilizing waste heat of a heat source for heating a conditioned room in a heat exchanger for heating, and a refrigerant CO2 is used as a refrigerant circuit with high pressure on the high pressure side, and a waste heat utilization circuit is constructed from a cascade heat exchanger that exchanges heat between the fluid flowing from the heat source to the heat exchanger for heating and the refrigerant in the refrigerant circuit. The purpose is to improve the performance and efficiency of the air conditioner.

  The air conditioning apparatus according to the first aspect of the present invention circulates fluid between a heat source and a heating heat exchanger, and uses the waste heat of the heat source for heating the conditioned room in the heating heat exchanger. Cascade heat exchange in which heat is exchanged between the refrigerant in the refrigerant circuit and the fluid that flows from the heat source to the heating heat exchanger in the waste heat utilization circuit using carbon dioxide as the refrigerant and the supercritical pressure on the high-pressure side, and the waste heat utilization circuit The refrigerant circuit includes a compressor, a cascade heat exchanger, a shunt, an auxiliary pressure reducing device, an internal heat exchanger, a main pressure reducing device, and a heat absorber provided outside the chamber to be conditioned. The discharged refrigerant is flowed to the cascade heat exchanger, the refrigerant that has exited the cascade heat exchanger is diverted by the flow divider, and one of the refrigerants is flowed from the auxiliary pressure reducing device to the internal heat exchanger to be discharged from the cascade heat exchanger. After exchanging heat with the refrigerant after exiting It was sucked into an intermediate pressure section of the compressor, after flowing the diverted other refrigerant from the main decompressor heat sink, and characterized in that sucked into the low pressure section of the compressor.

  The air conditioning apparatus according to the invention of claim 2 circulates a fluid through a heat source and a heat exchanger for heating, and uses the waste heat of the heat source for heating the conditioned room in the heating heat exchanger. Cascade heat exchange in which heat is exchanged between the refrigerant in the refrigerant circuit and the fluid that flows from the heat source to the heating heat exchanger in the waste heat utilization circuit using carbon dioxide as the refrigerant and the supercritical pressure on the high-pressure side, and the waste heat utilization circuit The refrigerant circuit comprises a compressor, a cascade heat exchanger, a shunt, an auxiliary pressure reducing device, an internal heat exchanger, a main pressure reducing device, and a cooling heat exchanger for cooling the conditioned room. The refrigerant discharged from the compressor is allowed to flow to the cascade heat exchanger, the refrigerant exiting the cascade heat exchanger is diverted by the flow divider, and one of the refrigerants is allowed to flow from the auxiliary pressure reducing device to the internal heat exchanger. Heat exchange with refrigerant after exiting heat exchanger After causes sucked into the intermediate pressure section of the compressor, after flowing into the heat exchanger for cooling the diverted other refrigerant from the main decompressor, characterized thereby sucked into the low pressure section of the compressor.

  The air conditioning apparatus according to the invention of claim 3 circulates a fluid through a heat source and a heating heat exchanger, and uses the waste heat of the heat source for heating the conditioned room in the heating heat exchanger. Cascade heat exchange in which heat is exchanged between the refrigerant in the refrigerant circuit and the fluid that flows from the heat source to the heating heat exchanger in the waste heat utilization circuit using carbon dioxide as the refrigerant and the supercritical pressure on the high-pressure side, and the waste heat utilization circuit The refrigerant circuit cools the compressor, the cascade heat exchanger, the shunt, the auxiliary decompressor, the internal heat exchanger, the main decompressor, the heat absorber provided outside the chamber to be conditioned, and the chamber to be conditioned. A cooling heat exchanger for cooling, the refrigerant discharged from the compressor is allowed to flow to the cascade heat exchanger, the refrigerant exiting the cascade heat exchanger is diverted by the flow divider, and one of the refrigerants is auxiliary decompressed Cascade heat flowing from the equipment to the internal heat exchanger After exchanging heat with the refrigerant that has come out of the converter, the refrigerant is sucked into the intermediate pressure part of the compressor and the other refrigerant that has been diverted during heating flows from the main decompressor to the heat absorber, and then the low pressure part of the compressor The other refrigerant, which is divided during the cooling, flows from the main decompression device to the cooling heat exchanger and is then sucked into the low pressure portion of the compressor.

  According to a fourth aspect of the present invention, there is provided the air conditioner according to any one of the first to third aspects, wherein the internal heat exchanger is one of the refrigerant having passed through the auxiliary pressure reducing device and the cascade heat exchanger. It is characterized in that heat is exchanged with the refrigerant before being diverted by the flow divider.

  An air conditioner according to a fifth aspect of the invention is characterized in that in the invention according to any one of the first to fourth aspects, one refrigerant is divided from an upper part and a lower part of the flow divider.

  An air conditioner according to a sixth aspect of the present invention is the air conditioning apparatus according to any one of the first to fifth aspects, wherein the compressor comprises a low-stage compression means and a high-stage compression means, and the heat absorber or the cooling heat. The refrigerant exiting the exchanger is sucked into the low-stage compression means, and the intermediate-pressure refrigerant compressed by the low-stage compression means is transferred to the high-stage compression means together with one refrigerant exiting the internal heat exchanger. In addition, the ratio of the displacement volume of the high-stage compression means to the displacement volume of the low-stage compression means is 70% to 85%.

  An air conditioner according to a seventh aspect of the invention comprises a temperature detection means for detecting the temperature of the refrigerant entering the main decompression device in the invention according to any one of the first to sixth aspects, and the temperature detection means detects this. The opening degree of the auxiliary pressure reducing device is controlled so that the temperature becomes the minimum value.

  An air conditioner according to an eighth aspect of the present invention comprises the temperature detection means for detecting the temperature of the refrigerant in the intermediate pressure portion of the compressor according to any of the first to seventh aspects, wherein the temperature detection means The opening degree of the auxiliary pressure reducing device is controlled so that the detected temperature becomes the maximum value.

  According to the air conditioning apparatus of the first aspect of the present invention, the fluid is circulated through the heat source and the heating heat exchanger, and the waste heat of the heat source is used for heating the conditioned room in the heating heat exchanger. Waste heat utilization circuit, a refrigerant circuit using carbon dioxide as a refrigerant, a supercritical pressure on the high pressure side, and a cascade for exchanging heat between the fluid flowing in the waste heat utilization circuit from the heat source to the heat exchanger for heating and the refrigerant in the refrigerant circuit The refrigerant circuit is constructed of a heat exchanger, a compressor circuit, a cascade heat exchanger, a shunt, an auxiliary pressure reducing device, an internal heat exchanger, a main pressure reducing device, and a heat absorber provided outside the conditioned chamber, and is compressed. The refrigerant discharged from the machine flows to the cascade heat exchanger, the refrigerant that exits the cascade heat exchanger is divided by the flow divider, and one refrigerant flows from the auxiliary decompressor to the internal heat exchanger to cascade heat exchange. Heat exchange with the refrigerant after leaving the vessel Then, the refrigerant is sucked into the intermediate pressure part of the compressor, and the other divided refrigerant flows from the main decompressor to the heat absorber and then sucked into the low pressure part of the compressor. By returning the refrigerant heated in step 1 to the intermediate pressure portion of the compressor, the amount of refrigerant flowing through the cascade heat exchanger can be increased without increasing the amount of refrigerant circulating through the refrigerant circuit.

  As a result, the amount of refrigerant that exchanges heat with the fluid in the cascade heat exchanger increases, and the heat exchange capability of the cascade heat exchanger can be improved. Further, the heat absorption between the one refrigerant having passed through the auxiliary pressure reducing device in the internal heat exchanger and the refrigerant having exited from the cascade heat exchanger and before being diverted by the flow divider is achieved by heat exchange. Since the specific enthalpy of the refrigerant entering the heater can be reduced, the heat absorption capability of the heat absorber can also be improved, and the heating capability can be further improved.

  Furthermore, by returning one refrigerant that has been diverted by the flow divider to the intermediate pressure portion of the compressor, the amount of refrigerant compressed in the low pressure portion of the compressor can be reduced, so the compression power of the compressor The operating efficiency of the compressor can be improved.

  As a result, the efficiency and performance of the air conditioner using carbon dioxide refrigerant can be improved.

  According to the air conditioning apparatus of the second aspect of the present invention, the fluid is circulated through the heat source and the heating heat exchanger, and the waste heat of the heat source is used for heating the conditioned room in the heating heat exchanger. Waste heat utilization circuit, a refrigerant circuit using carbon dioxide as a refrigerant, a supercritical pressure on the high pressure side, and a cascade for exchanging heat between the fluid flowing in the waste heat utilization circuit from the heat source to the heat exchanger for heating and the refrigerant in the refrigerant circuit The refrigerant circuit is composed of a compressor, a cascade heat exchanger, a shunt, an auxiliary decompressor, an internal heat exchanger, a main decompressor, and a cooling heat exchanger for cooling the conditioned room The refrigerant discharged from the compressor is allowed to flow to the cascade heat exchanger, the refrigerant exiting the cascade heat exchanger is diverted by the flow divider, and one refrigerant is allowed to flow from the auxiliary pressure reducing device to the internal heat exchanger. Refrigerant after exiting the cascade heat exchanger After heat exchange, the refrigerant is sucked into the intermediate pressure part, and the other refrigerant that has been diverted flows from the main decompressor to the cooling heat exchanger and then sucked into the low pressure part of the compressor. The amount of refrigerant discharged from the compressor can be increased without increasing the circulation amount of the refrigerant flowing through the refrigerant circuit by returning the refrigerant that has been flown and heated by the internal heat exchanger to the intermediate pressure portion of the compressor. .

  Therefore, since the heat dissipation capability of the refrigerant is improved, the enthalpy of the refrigerant entering the cooling heat exchanger is reduced correspondingly, and the refrigeration effect can be improved. Furthermore, heat exchange is performed between the one refrigerant that has passed through the auxiliary pressure reduction device in the internal heat exchanger and the refrigerant that has left the cascade heat exchanger and has not been divided by the flow divider, Thus, the specific enthalpy of the refrigerant entering the heat exchanger can be further reduced, and the refrigeration effect can be further improved.

  In addition, by returning one of the refrigerants divided by the flow divider to the intermediate pressure part of the compressor, the amount of refrigerant compressed in the low pressure part of the compressor can be reduced, so the compression power of the compressor The operating efficiency of the compressor can be improved.

  As a result, the efficiency and performance of the air conditioner using carbon dioxide refrigerant can be improved.

  According to the air conditioner of the invention of claim 3, fluid is circulated between the heat source and the heating heat exchanger, and the waste heat of the heat source is used for heating the conditioned room in the heating heat exchanger. Waste heat utilization circuit, a refrigerant circuit using carbon dioxide as a refrigerant, a supercritical pressure on the high pressure side, and a cascade for exchanging heat between the fluid flowing in the waste heat utilization circuit from the heat source to the heat exchanger for heating and the refrigerant in the refrigerant circuit The refrigerant circuit is composed of a compressor, a cascade heat exchanger, a shunt, an auxiliary pressure reducing device, an internal heat exchanger, a main pressure reducing device, a heat absorber provided outside the room to be conditioned, and a room to be conditioned. A cooling heat exchanger for cooling, the refrigerant discharged from the compressor is allowed to flow to the cascade heat exchanger, the refrigerant exiting the cascade heat exchanger is diverted by the flow divider, and one refrigerant is Flow from auxiliary decompressor to internal heat exchanger After exchanging heat with the refrigerant after exiting from the heat exchanger, the refrigerant is sucked into the intermediate pressure part of the compressor, and the other refrigerant that has been diverted during heating is flowed from the main decompressor to the heat absorber. The other refrigerant that has been sucked into the low-pressure part and diverted during cooling flows from the main decompressor to the cooling heat exchanger and then sucked into the low-pressure part of the compressor, so it is divided by the flow divider and heated by the internal heat exchanger. By returning the obtained refrigerant to the intermediate pressure portion of the compressor, the amount of refrigerant flowing through the cascade heat exchanger can be increased without increasing the circulation amount of the refrigerant flowing through the refrigerant circuit.

  As a result, the amount of refrigerant that exchanges heat with the fluid in the cascade heat exchanger increases, and the heat exchange capability of the cascade heat exchanger can be improved. In addition, by returning one of the refrigerants divided by the flow divider to the intermediate pressure part of the compressor, the amount of refrigerant compressed in the low pressure part of the compressor can be reduced, so the compression power of the compressor The operating efficiency of the compressor can be improved.

  Furthermore, heat exchange is performed by exchanging heat between one refrigerant that has passed through the auxiliary pressure reduction device in the internal heat exchanger and the refrigerant that has left the cascade heat exchanger and has not been divided by the flow divider. Since the specific enthalpy of the refrigerant entering the heat absorber during operation can be reduced, the heat absorption capability of the heat absorber can also be improved, and the heating capability can be further improved.

  On the other hand, during the cooling operation, the specific enthalpy of the refrigerant entering the cooling heat exchanger can be further reduced, and the refrigeration effect can be further improved.

  As described in detail above, according to the present invention, the efficiency and performance of an air conditioner using a carbon dioxide refrigerant can be improved.

  In the invention of claim 5, in each of the above inventions, by dividing one refrigerant from the upper and lower parts of the flow divider, the oil discharged from the compressor to the refrigerant circuit in the flow divider is compressed together with the one refrigerant. It becomes possible to return to the intermediate pressure part of the machine.

  In each of the above inventions, the compressor includes a low-stage compression means and a high-stage compression means, and the refrigerant discharged from the heat absorber or the heat exchanger for cooling is sucked into the low-stage compression means. The intermediate-pressure refrigerant compressed by the low-stage compression means is sucked into the high-stage compression means together with one refrigerant that has exited the internal heat exchanger, and the high-stage refrigerant with respect to the excluded volume of the low-stage compression means If the ratio of the excluded volume of the side compression means is 70% or more and 85% or less, it is possible to maintain the best efficiency.

  Furthermore, if the temperature detection means for detecting the temperature of the refrigerant entering the main pressure reduction device as in claim 7 is provided, and the opening of the auxiliary pressure reduction device is controlled so that the temperature detected by this temperature detection means is the minimum value, The efficiency of the air conditioner can be further improved.

  Furthermore, the temperature detecting means for detecting the temperature of the refrigerant in the intermediate pressure portion of the compressor as in claim 8 is provided, and the opening of the auxiliary pressure reducing device is controlled so that the temperature detected by the temperature detecting means becomes the maximum value. Then, the efficiency of the air conditioner can be further improved.

  Hereinafter, embodiments of the air-conditioning apparatus of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic view of an air conditioner according to an embodiment of the present invention. The air conditioner of this embodiment is used as a car air conditioner, and exchanges heat between the waste heat utilization circuit 1, the refrigerant circuit 10, the fluid flowing through the waste heat utilization circuit 1, and the refrigerant flowing through the refrigerant circuit 10. And a cascade heat exchanger 12 for the purpose. The waste heat utilization circuit 1 is for utilizing the waste heat of the heat source 2 composed of an engine such as HEV or FCV for heating the vehicle interior as a conditioned room. The heat source 2 and the heating heat exchanger 4 Are connected to each other in an annular shape, and the circulation pump 5 is configured to circulate the fluid flowing in the piping.

  That is, the pipe 2A connected to the outlet of the heat source 2 is connected to the inlet of the passage 12B of the cascade heat exchanger 12, and the pipe 3 connected to the outlet of the passage 12B is connected to the inlet of the heating heat exchanger 4. The The pipe 4A exiting the heating heat exchanger 4 is connected to the inlet of the circulation pump 5, the one end of the pipe 5A is connected to the outlet of the circulation pump 5, and the other end of the pipe 5A reaches the inlet of the three-way valve 8. . The three-way valve 8 is a flow path control means for controlling whether or not the fluid circulated by the circulation pump 5 flows to the heat source 2 and is controlled by a control means (not shown).

  One outlet of the three-way valve 8 is connected to the inlet of the heat source 2 via the pipe 5B, and the other outlet is connected to one end of the bypass pipe 7A. The bypass pipe 7A is a pipe for sequentially flowing the fluid circulated by the circulation pump 5 to the cascade heat exchanger 12 and the heating heat exchanger 4 while bypassing the heat source 2, and the other end of the bypass pipe 7A. Is connected to the middle part of the pipe 2A located upstream of the cascade heat exchanger 12 of the pipe 2A.

  When the temperature of the heat source 2 is low, such as immediately after the heat source 2 is started, the three-way valve 8 is controlled so that the fluid from the pipe 5A flows to the bypass pipe 7A. Further, when the temperature of the heat source 2 rises, for example, when the heat source 2 rises to a predetermined temperature set in advance, the three-way valve 8 is controlled by the control means so that the fluid from the pipe 5A flows into the pipe 5B.

  In this embodiment, the air conditioner is used as a car air conditioner and the heat source is an engine such as HEV or FCV. However, the air conditioner of the present invention is used as a cogeneration system or the like in addition to being applied to a car air conditioner. In this case, the heat source includes FC.

  On the other hand, the refrigerant circuit 10 is a refrigerant circuit in which carbon dioxide is used as a refrigerant and the high pressure side becomes a supercritical pressure. The compressor 11, the cascade heat exchanger 12, the heating diverter 13 as a diverter, and the cooling diversion , Heating auxiliary expansion valve 15 and cooling auxiliary expansion valve 16 as auxiliary pressure reducing devices, heating auxiliary heat exchanger 17 and cooling auxiliary heat exchanger 18 as internal heat exchangers, heating as main pressure reducing device An expansion valve 20 for cooling, an expansion valve 21 for cooling, an outdoor heat exchanger 23 as a heat absorber provided outside the vehicle interior, a heat exchanger 24 for cooling for cooling the vehicle interior, and the like.

  The compressor 11 includes a drive element (not shown) in the hermetic container 30, a first compression element 32 as a low-stage compression means driven by a drive shaft of the drive element, and a first compression element as a high-stage compression means. This is a multi-stage (two-stage) compression compressor that houses the two compression elements 34. Then, the refrigerant discharged from the outdoor heat exchanger 23 or the cooling heat exchanger 24 is sucked into the first compression element 32 and compressed, and the intermediate pressure refrigerant compressed by the first compression element 32 is sealed. After being discharged into the container 30, it is combined with one of the refrigerants coming out of the heating auxiliary heat exchanger 17 of the heating auxiliary circuit 70, which will be described later, or the cooling auxiliary heat exchanger 18 of the cooling auxiliary circuit 75. The compression element 34 is sucked and compressed. In this embodiment, it is assumed that the compressor 11 in which the excluded volume ratio of the second compression element 34 to the first compression element 32 is 70% or more and 85% or less is used.

  One end of a refrigerant introduction pipe 40 is connected to the suction side of the first compression element 32, and a low-temperature and low-pressure refrigerant gas is introduced into the first compression element 32 serving as a low-stage compression means from here. . The other end of the refrigerant introduction pipe 40 branches into two, one pipe 40A is connected to the outlet of the cooling heat exchanger 24, and the other pipe 40B is connected to the cooling shunt 14 via the electromagnetic valve 27. It is connected to the middle part of the refrigerant pipe 58 connected to the other outlet.

  In addition, one end of a refrigerant discharge pipe 42 is connected to the discharge side of the second compression element 34, and high temperature and high pressure compressed by the second compression element 34 on the higher stage side from the refrigerant discharge pipe 42. The refrigerant gas is discharged to the outside of the compressor 11. The refrigerant discharge pipe 42 is connected to the passage 12 </ b> A of the cascade heat exchanger 12. The cascade heat exchanger 12 is for exchanging heat between the high-temperature and high-pressure refrigerant gas flowing from the compressor 11 and flowing in the refrigerant circuit 10 and the fluid flowing in the waste heat utilization circuit 1, and the passage 12A and the passage 12B Are arranged so that heat exchange is possible. Then, the high-temperature and high-pressure refrigerant gas exiting from the compressor 11 flows through the passage 12A of the cascade heat exchanger 12, and the fluid of the waste heat utilization circuit 1 flows through the passage 12B. Further, an inlet of the passage 12A and an outlet of the passage 12B are formed at one end of the cascade heat exchanger 12, and an outlet of the passage 12A and an outlet of the passage 12B are formed at the other end, respectively. Therefore, in the cascade heat exchanger 12, the refrigerant in the refrigerant circuit 10 that flows through the pipe 12A and the fluid in the waste heat utilization circuit 1 that flows through the pipe 12B become counterflows.

  On the other hand, the refrigerant pipe 43 exiting the passage 12A of the cascade heat exchanger 12 is connected to the inlet of the passage 17A of the auxiliary heating heat exchanger 17. The heating auxiliary heat exchanger 17 is divided by the refrigerant after coming out of the cascade heat exchanger 12 during heating operation, which will be described later, and the heating diverter 13, and is provided in the heating auxiliary circuit 70. This is for exchanging heat with the refrigerant depressurized by the valve 15 (one refrigerant diverted by the heating diverter 13), and the passage 17A and the passage 17B are arranged to be able to exchange heat. . Then, the refrigerant after exiting the cascade heat exchanger 12 flows through the passage 17A of the auxiliary heating heat exchanger 17 during the heating operation, flows through the passage 17B in the heating diverter 13, and flows into the auxiliary heating circuit 70. Then, the refrigerant depressurized by the heating auxiliary expansion valve 15 flows. In the heating heat exchanger 17, the inlet of the passage 17A and the passage 17B are connected to one end of the heating auxiliary heat exchanger 17 so that the refrigerant flowing in the passage 17A and the refrigerant flowing in the passage 17B are opposed to each other. The outlet of the passage 17A and the outlet of the passage 17B are formed at the other end.

  The refrigerant pipe 45 connected to the outlet of the passage 17 </ b> A of the heating auxiliary heat exchanger 17 is connected to the inlet of the heating diverter 13. The heating diverter 13 converts the refrigerant from the heating auxiliary heat exchanger 17 during the heating operation into two refrigerant flows, a first refrigerant flow (one refrigerant) and a second refrigerant flow (the other refrigerant). Refrigerant branching means for diverting the refrigerant, and a refrigerant pipe 47 of the heating auxiliary circuit 70 for the first refrigerant flow (one refrigerant) is connected to one outlet of the heating diverter 13. A refrigerant pipe 48 for the second refrigerant flow (the other refrigerant) is connected to the other outlet of the heating flow divider 13.

  The heating auxiliary circuit 70 is a circuit for decompressing and expanding one refrigerant divided by the heating diverter 13 and then sucking it into the sealed container 30 as an intermediate pressure portion of the compressor 11. The heating auxiliary circuit 70 is provided with a heating auxiliary expansion valve 15 for decompressing one of the refrigerants diverted by the heating flow divider 13. That is, the refrigerant pipe 47 connected to one outlet of the heating diverter 13 is connected to the inlet of the heating auxiliary expansion valve 15. The outlet of the auxiliary heating expansion valve 15 is connected to the inlet of the passage 17B of the auxiliary heating heat exchanger 17. As a result, the refrigerant decompressed by the auxiliary heating expansion valve 15 is caused to flow through the auxiliary heating heat exchanger 17 for heat exchange with the refrigerant on the high-pressure side coming out of the cascade heat exchanger 12, so that the pipe 17B is The flowing refrigerant can be expanded. In addition, a refrigerant introduction pipe 41 is connected to the outlet of the passage 17B, and one refrigerant divided by the heating diverter 13 is sucked into the sealed container 30 which is an intermediate pressure portion of the compressor 11 from here.

  Here, the heating diverter 13 used in the present embodiment will be described with reference to FIG. In FIG. 2, 13A is a main body of the heating diverter 13. The main body 13A has an inlet formed on one side (the right side in FIG. 2), and the inlet is a refrigerant pipe from which the auxiliary heating heat exchanger 17 is discharged. 45 is connected. The other outlet is formed on the other side of the main body 13A (left side in FIG. 2), that is, on the diagonal line of the inlet to which the refrigerant pipe 45 is connected, and the refrigerant pipe 48 reaching the heating expansion valve 20 is formed at the outlet. It is connected. Further, one outlet is formed in the upper and lower parts of the main body 13A, one end of the refrigerant pipe 47A is formed in one outlet formed in the upper part, and one end of the refrigerant pipe 47B is formed in one outlet formed in the lower part. Are connected to each other. The other end of the refrigerant pipe 47A connected to the upper part is connected to the middle part of the refrigerant pipe 47B connected to the lower part, and the other end of the refrigerant pipe 47B is connected to the inlet of the auxiliary heating expansion valve 15 for heating. . Thereby, one refrigerant can be divided from the upper part and the lower part of the heating diverter 13 and can be caused to flow to the heating auxiliary circuit 70.

  The structure of the heating flow divider 13 is not limited to the structure described with reference to FIG. 2, and any structure that can divide the refrigerant from the cascade heat exchanger 12 into two refrigerant flows may be used. In addition, in the invention of claim 5, any one that can divert one refrigerant from the upper part and the lower part of the diverter may be used. For example, a diverter having a structure shown in FIG. 3 may be used. In the flow divider 80 shown in FIG. 3, an inlet is formed on one side (right side in FIG. 3) of the main body 80A in the same manner as the flow divider described in FIG. 2, and the refrigerant that has exited the heating auxiliary heat exchanger 17 is formed in the inlet. A pipe 45 is connected. Similarly, the other outlet is formed on the other side of the main body 80A (the left side in FIG. 3), that is, on the diagonal line of the inlet to which the refrigerant pipe 45 is connected, and the outlet reaches the heating expansion valve 20 at the outlet. 48 is connected. Further, one outlet is formed in the lower part of the main body 80A, and a refrigerant pipe 82 reaching the heating auxiliary expansion valve 15 is connected to the one outlet. The refrigerant pipe 82 is inserted into the main body 80A, and one end is opened above the main body 80A so that the refrigerant in the upper part of the main body 80A of the flow divider 80 can flow into the refrigerant pipe 82 from here. Further, a communication port 83 that connects the refrigerant pipe 82 and the lower part of the main body 80A is formed below the main body 80A of the refrigerant pipe 82, and the refrigerant in the lower part of the main body 80A of the flow divider 80 is supplied from the communication port 83 to It can flow into the pipe 82. As described above, even when the flow divider 80 of FIG. 3 is used, one of the refrigerants can be divided from the upper and lower portions of the flow divider 80 and can flow to the heating auxiliary circuit 70.

  On the other hand, the refrigerant pipe 48 connected to the other outlet of the heating diverter 13 reaches the heating expansion valve 20. The heating expansion valve 20 is a main pressure reducing device for reducing the pressure of the other refrigerant divided by the heating flow divider 13 during the heating operation. An outdoor heat exchanger 23 is provided at the outlet side of the heating expansion valve 20. Is provided. The outdoor heat exchanger 23 functions as a heat absorber during heating operation. That is, during the heating operation, the refrigerant decompressed by the heating expansion valve 20 as the main decompression device exchanges heat with the outside air in the outdoor heat exchanger 23, thereby pumping up heat (absorbing heat) from the outside air. . The outdoor heat exchanger 23 is used as a radiator that radiates heat to the outside air during cooling operation or dehumidifying operation described later.

  The refrigerant pipe 50 exiting the outdoor heat exchanger 23 is connected to the inlet of the passage 18A of the cooling auxiliary heat exchanger 18. The cooling auxiliary heat exchanger 18 is divided into the refrigerant after it is discharged from the cascade heat exchanger 12 during cooling operation, which will be described later, and the cooling diverter 14, and is provided with a cooling auxiliary circuit 75. This is for exchanging heat with the refrigerant depressurized by the valve 16 (one refrigerant diverted by the cooling flow divider 14), and the passage 18A and the passage 18B are arranged to be able to exchange heat. . Then, the refrigerant after exiting the cascade heat exchanger 12 flows through the passage 18A of the cooling auxiliary heat exchanger 18 during cooling operation, flows through the passage 18B by the cooling flow divider 14, and flows into the cooling auxiliary circuit 75. Then, the refrigerant depressurized by the cooling auxiliary expansion valve 16 flows. In the cooling heat exchanger 18, the inlet of the passage 18A and the passage 18B are provided at one end of the cooling auxiliary heat exchanger 18 so that the refrigerant flowing through the passage 18A and the refrigerant flowing through the passage 18B are opposed to each other. The outlet of the passage 18A and the outlet of the passage 18B are formed at the other end.

  The refrigerant pipe 52 connected to the outlet of the passage 18A of the cooling auxiliary heat exchanger 18 is connected to the inlet of the cooling flow divider 14. The cooling diverter 14 converts the refrigerant from the cooling auxiliary heat exchanger 18 during the cooling operation into two refrigerant flows, a first refrigerant flow (one refrigerant) and a second refrigerant flow (the other refrigerant). Refrigerant branching means for branching for branching, and a refrigerant pipe 54 of a cooling auxiliary circuit 75 for the first refrigerant flow (one refrigerant) is connected to one outlet of the cooling flow divider 14. Has been. A refrigerant pipe 58 for a second refrigerant flow (the other refrigerant) is connected to the other outlet of the cooling flow divider 14.

  The cooling auxiliary circuit 75 is a circuit for decompressing and expanding one refrigerant divided by the cooling diverter 14 and then sucking it into the sealed container 30 as an intermediate pressure portion of the compressor 11. The cooling auxiliary circuit 75 is provided with a cooling auxiliary expansion valve 16 for reducing the pressure of one refrigerant divided by the cooling flow divider 14. That is, the refrigerant pipe 54 connected to one outlet of the cooling flow divider 14 is connected to the inlet of the cooling auxiliary expansion valve 16. The outlet of the cooling auxiliary expansion valve 16 is connected to the inlet of the passage 18B of the cooling auxiliary heat exchanger 18. Thereby, the refrigerant decompressed by the cooling auxiliary expansion valve 16 during the cooling operation is caused to flow to the cooling auxiliary heat exchanger 18 to exchange heat with the high-pressure side refrigerant discharged from the cascade heat exchanger 12, The refrigerant flowing through the passage 18B can be expanded. Further, one end of the refrigerant pipe 57 is connected to the outlet of the passage 18B, and the other end of the refrigerant pipe 57 is connected to the middle part of the refrigerant introduction pipe 41 described above, and the intermediate pressure of the compressor 11 is communicated from the refrigerant introduction pipe 41. One refrigerant that has been diverted by the cooling diverter 14 is sucked into the airtight container 30 that is a part.

  The cooling diverter 14 uses the refrigerant diverting means having the same configuration as that of the heating diverter 13 described with reference to FIG. 2, but is not limited thereto, and the refrigerant discharged from the cascade heat exchanger 12 is used. Any structure can be used as long as it can be divided into two refrigerant streams. Further, in the invention of claim 5, any shunt having a configuration capable of shunting one shunt from the upper part and the lower part may be used, and the shunt having the structure shown in FIG. Is also applicable.

  A refrigerant temperature sensor 30 </ b> S for detecting the refrigerant temperature in the sealed container 30 is installed in the sealed container 30 of the compressor 11. Further, refrigerant temperature sensors 48S and 58S are also installed in the refrigerant pipe 48 and the refrigerant pipe 58, respectively. The refrigerant temperature sensor 48S is a refrigerant temperature detecting means for detecting the refrigerant temperature entering the heating expansion valve 20 (main pressure reducing device during heating operation), and the refrigerant temperature sensor 58S is the cooling expansion valve 21 (in the cooling operation). The refrigerant temperature detecting means detects the refrigerant temperature entering the main decompression device. Further, the refrigerant pipe 47 is provided with a refrigerant temperature sensor 47S as refrigerant temperature detecting means for detecting the temperature of one refrigerant entering the auxiliary heating heat exchanger 17, and the refrigerant introduction pipe 41 is provided with A refrigerant temperature sensor 41S is provided as refrigerant temperature detection means for detecting one refrigerant that has come out of the auxiliary heat exchanger 17 for heating.

  Each refrigerant temperature sensor 30S, 48S, 58S, 47S, 41S is connected to a control means (not shown) that controls the air conditioner of the present invention.

(1) During heating operation Next, the operation of the air conditioner will be described with the above configuration. First, regarding the operation during the heating operation, the operation during the heating operation when the temperature of the heat source 2 is low, such as when the air conditioner is started, will be described with reference to FIG. In FIG. 4, arrows indicate the flow of the refrigerant flowing through the refrigerant circuit 10 and the fluid flowing through the waste heat utilization circuit 1. During the heating operation, as shown in FIG. 5, the control means fully closes the cooling expansion valve 21 and the cooling auxiliary expansion valve 16 and fully opens the electromagnetic valve 27, and the heating auxiliary expansion valve 15 and The degree of opening of the refrigerant flowing through the heating expansion valve 20 is controlled so that the pressure can be reduced. The control means controls the three-way valve 8 so that the fluid from the circulation pump 5 does not flow to the heat source 2 but flows to the bypass pipe 7A, and starts the fan 4F of the circulation pump 5 and the heat exchanger 4 for heating. Thereby, the fluid flows into the passage 12B from the other end of the cascade heat exchanger 12 through the bypass circuit 7A from the three-way valve 8, and from the refrigerant flowing through the passage 12A in the process of flowing through the passage 12B of the cascade heat exchanger 12. Deprived of heat and heated.

  Then, the fluid exiting from one end of the cascade heat exchanger 12 enters the heating heat exchanger 4. Here, the fluid is cooled by exchanging heat with the surrounding air. On the other hand, the air heated by exchanging heat with the fluid is blown by the fan 4F into the vehicle interior which is a conditioned room. Thereby, the vehicle interior is heated. On the other hand, the air cooled by exchanging heat with air in the heating heat exchanger 4 is extracted from the heating heat exchanger 4 and sucked into the circulation pump 5 through the pipe 4A and discharged to the pipe 5A. The cycle of flowing through the passage 12B of the cascade heat exchanger 12 through the three-way valve 8 and the bypass circuit 7A is repeated.

  On the other hand, when the drive element of the compressor 11 is driven by the control means (at this time, the fan 24F of the cooling heat exchanger 24 is stopped), the low-pressure chamber of the first compression element 32 is supplied from the refrigerant introduction pipe 40. A low-temperature and low-pressure refrigerant gas is sucked into the side and compressed. Thereby, the refrigerant compressed to the intermediate pressure by the first compression element 32 is discharged into the sealed container 30 from the high pressure chamber side. The refrigerant discharged into the hermetic container 30 joins the first refrigerant flow (one refrigerant diverted by the heating diverter 13) from the heating auxiliary circuit 70 in the hermetic container 30.

  Thereafter, the merged refrigerant is sucked into the low-pressure chamber side of the second compression element 34 and compressed to become high-temperature and high-pressure refrigerant gas, enters the refrigerant discharge pipe 42 from the high-pressure chamber side, and is discharged to the outside of the compressor 11. . At this time, the refrigerant is compressed to an appropriate supercritical pressure. The refrigerant gas discharged from the compressor 11 is mixed with oil that has been supplied to the sliding portion of the second compression element 34 of the compressor 11.

  The refrigerant discharged from the refrigerant discharge pipe 42 enters the cascade heat exchanger 12 through an inlet of a passage 12 </ b> A formed at one end of the cascade heat exchanger 12. The high-temperature and high-pressure refrigerant that has flowed out of the compressor 11 passes through the passage 12A of the cascade heat exchanger 12 and becomes a fluid in the waste heat utilization circuit 1 that flows through the passage 12B that is exchanged with the passage 12A. Deprived of heat and cooled.

  The refrigerant in the passage 12 </ b> A cooled by the cascade heat exchanger 12 exits the cascade heat exchanger 12 from the other end and enters the heating auxiliary through the inlet of the passage 17 </ b> A formed on one end side of the auxiliary heating heat exchanger 17. Enters heat exchanger 17. The high-pressure side refrigerant that has flowed out of the cascade heat exchanger 12 passes through the passage 17A of the heating auxiliary heat exchanger 17, and the low-pressure side refrigerant that flows through the passage 17B that is exchanged with the passage 17A. Heat is deprived by (one refrigerant that is diverted by the heating diverter 13 and flows through the auxiliary heating circuit 70). Thereby, the refrigerant gas on the high pressure side flowing through the passage 17A can be cooled, and the specific enthalpy of the refrigerant entering the outdoor heat exchanger 23 can be reduced.

  Therefore, the heat absorption capability in the outdoor heat exchanger 23 is also improved, and the heating capability can be further improved. In particular, heat exchange in which heat is exchanged between the conventional refrigerant and air by cooling the high-pressure refrigerant from the cascade heat exchanger 12 with one of the refrigerant diverted with the heating diverter 13 in the auxiliary heat exchanger 17 for heating. It is possible to improve the heating capacity more compactly and at a lower cost than the heater.

  The refrigerant in the passage 17A cooled by the heating auxiliary heat exchanger 17 exits the heating auxiliary heat exchanger 17 from the other end and enters the heating diverter 13, where the first refrigerant flow (one of the refrigerant flows) The refrigerant is branched into two refrigerant streams, that is, a refrigerant) and a second refrigerant stream (the other refrigerant). At this time, since the heating diverter 13 is configured to divert one refrigerant from the upper and lower portions of the diverter 13 as described above, oil as described later can be taken out together with the one refrigerant.

  Then, one refrigerant (one refrigerant and oil) diverted by the heating diverter 13 enters the heating auxiliary circuit 70 and reaches the heating auxiliary expansion valve 15. The refrigerant that has passed through the heating auxiliary expansion valve 15 is still in a supercritical state, and in this state, the heating auxiliary is supplied from the inlet of the passage 17B formed at the other end of the heating auxiliary heat exchanger 17. It flows into the heat exchanger 17 and expands. At this time, the refrigerant (one refrigerant) flowing through the passage 17B takes heat away from the refrigerant flowing through the passage 17A and evaporates.

  In this manner, the heating auxiliary heat exchanger 17 exchanges heat with the high-pressure refrigerant flowing through the passage 17A, whereby the low-pressure refrigerant (one refrigerant) flowing through the passage 17B can be evaporated. The evaporated low-pressure side refrigerant (including oil) exits the heating auxiliary heat exchanger 17 from the outlet of the passage 17B formed at one end, enters the refrigerant introduction pipe 41, and the sealed container 30 of the compressor 11. Sucked into. Then, the refrigerant sucked into the sealed container 30 merges with the intermediate pressure refrigerant compressed by the first compression element 32. Further, the oil sucked into the sealed container 30 together with the refrigerant is separated from the refrigerant in the sealed container 30 and returns to the oil sump formed at the bottom. Thereby, the oil discharged to the outside of the compressor 11 can be returned into the sealed container 30.

  In particular, when carbon dioxide is used as a refrigerant, the density difference between carbon dioxide and oil varies greatly depending on the pressure and temperature of carbon dioxide. In this case, the density difference between the PAG oil and the carbon dioxide refrigerant when PAG is used as the oil is shown in FIG. As shown in FIG. 6, the density of carbon dioxide is higher than the density of oil at low temperatures, and the difference decreases as the temperature rises. When the temperature is about −5 ° C. or higher, the density of carbon dioxide is lower than the density of PAG oil. I understand that. Therefore, when one refrigerant is diverted from only the upper part in the heating diverter 13, if the temperature is -5 ° C. or lower, the PAG oil can be taken out together with the one refrigerant and flowed to the heating auxiliary circuit 70. When the temperature is −5 ° C. or higher, the density of the PAG oil becomes larger than the density of carbon dioxide, so that the oil cannot flow through the heating auxiliary circuit 70 together with one refrigerant, and the expansion for heating together with the other refrigerant. It will flow to the valve 20.

  In addition, when one refrigerant is divided from only the lower part in the heating diverter 13, if the temperature is −5 ° C. or higher, the oil can be taken out together with the one refrigerant and flowed to the heating auxiliary circuit 70. Is less than −5 ° C., the density of oil becomes smaller than the density of carbon dioxide, so that the oil cannot flow to the heating auxiliary circuit 70 together with one refrigerant, and the heating expansion valve 20 together with the other refrigerant. To flow into.

  On the other hand, FIG. 7 shows the density difference between the PVE oil and the carbon dioxide refrigerant when PVE is used as the oil. As shown in FIG. 7, the density of carbon dioxide is also higher than the density of oil when the PVE oil is at a low temperature, and the difference becomes smaller as the temperature rises. It turns out that it becomes small. Accordingly, when one of the refrigerants is divided from only the upper portion in the heating diverter 13, if the temperature is 0 ° C. or less, the oil can be taken out together with the one refrigerant and flowed to the heating auxiliary circuit 70. When the temperature is 0 ° C. or higher, the density of the oil becomes larger than the density of carbon dioxide, so that the oil cannot flow to the heating auxiliary circuit 70 together with one refrigerant and flows to the heating expansion valve 20 together with the other refrigerant. It becomes like this.

  Further, when one refrigerant is divided from only the lower part in the heating diverter 13, if the temperature is 0 ° C. or higher, the oil can be taken out together with the one refrigerant and flowed to the heating auxiliary circuit 70. When the temperature is 0 ° C. or lower, the density of the oil is smaller than the density of carbon dioxide, so that the oil cannot flow to the heating auxiliary circuit 70 together with one refrigerant and flows to the heating expansion valve 20 together with the other refrigerant. It becomes like this.

  Therefore, in the shunt of the conventional structure, as described above, one refrigerant is shunted from either the upper part or the lower part of the shunt, so that the density difference between the refrigerant and the oil varies. It was difficult to cope with it, and it was difficult to always let oil flow along the auxiliary circuit along with one of the refrigerants. Accordingly, the oil cannot be returned to the compressor 11 via the auxiliary circuit, so that the oil in the compressor 11 may be reduced and the oil may be insufficient. In addition, the oil circulates in the refrigerant circuit 10 together with the other refrigerant, so that the oil accumulates in the refrigerant circuit 10, thereby obstructing a good flow of the refrigerant and causing a pressure loss. There was a risk of reducing the performance of the entire apparatus.

  However, when the heating diverter 13 has a shape in which one refrigerant is diverted from the upper part and the lower part as in the present invention, even when the density of the oil becomes larger than the density of carbon dioxide, it becomes a case where it becomes smaller. However, it is possible to divert the oil from either the upper part or the lower part, and flow the oil together with one refrigerant to the heating auxiliary circuit 70, and reliably return the oil from the circuit 70 into the sealed container 30 of the compressor 11. .

  That is, when the density of the oil is higher than the density of carbon dioxide, the oil accumulates in the lower portion of the main body 13A. Therefore, the oil accumulated in the lower portion is branched from the other refrigerant together with one refrigerant flow, and the heating auxiliary circuit 70 Can be shed.

  Further, when the density of the oil is smaller than that of carbon dioxide, the oil accumulates in the upper part of the main body 13A. Therefore, the oil accumulated in the upper part is branched from the other refrigerant together with one refrigerant flow, and the heating auxiliary circuit 70 Can be shed. Thereby, in the refrigerant circuit 10 of the air conditioner using carbon dioxide as a refrigerant, the oil discharged to the outside of the compressor 11 can be returned directly into the sealed container 30 of the compressor 11.

  Further, by returning the one refrigerant divided by the heating diverter 13 into the hermetic container 30 that is an intermediate pressure part of the compressor 11, the second circulation amount is increased without increasing the circulation amount of the refrigerant flowing through the refrigerant circuit 10. Therefore, the amount of refrigerant flowing into the gas cooler heat exchanger 12 can be increased. As a result, the amount of refrigerant that exchanges heat with the fluid in the cascade heat exchanger 12 increases, and the heat exchange capability of the cascade heat exchanger 12 can be improved. In particular, the amount of refrigerant compressed by the first compression element 32 of the compressor 11 by returning one refrigerant divided by the heating flow divider 13 into the sealed container 30 that is an intermediate pressure portion of the compressor 11. Therefore, it is possible to reduce the compression power of the compressor 11 and improve the operation efficiency.

  FIG. 8 shows a heating capacity characteristic when the vehicle interior is heated using the refrigerant circuit 10 of the present embodiment and a heating capacity characteristic when the vehicle interior is heated using the conventional refrigerant circuit. In FIG. 8, black circles indicate the heating characteristics of the conventional air conditioner, and black squares indicate the heating characteristics of the air conditioner of the present invention. Further, the triangle indicates the ratio of the heating capacity characteristic of the present invention to the conventional heating capacity characteristic (the heating characteristic of the air conditioner of the present invention / the heating characteristic of the conventional air conditioner).

  As is apparent from FIG. 8, it can be seen that the heating capacity is improved as compared with the conventional air conditioner by applying the present invention. In particular, as shown by the triangular plots in the figure (heating characteristics of the air conditioner of the present invention / heating characteristics of the conventional air conditioner), the evaporation temperature in the outdoor heat exchanger 23 is low, and under severe conditions during heating The greater the effect, the greater the effect of the air conditioner to which the present invention is applied.

  In a conventional apparatus using an HFC-based refrigerant, when a so-called split type refrigerant circuit that divides the refrigerant flow as in the present invention is used in the refrigerant circuit, if the circulation amount on the high-pressure side increases, the high-pressure pressure Since the compression power increases and the compression power increases, it is difficult to adopt such a refrigerant circuit because improvement in efficiency cannot be obtained. However, since the carbon dioxide refrigerant uses the high-pressure side as the supercritical pressure, the increase in the high-pressure side pressure is useful for improving the capacity, and therefore the increase in the compression power corresponding to the pressure increase does not adversely affect the efficiency.

  As described above, according to the present invention, it is possible to improve the efficiency and performance of an air conditioner in which the high pressure side of the refrigerant circuit 10 is supercritical using carbon dioxide refrigerant.

  On the other hand, the other refrigerant (second refrigerant flow) divided by the heating diverter 13 is transferred to the heating expansion valve 20 via the refrigerant pipe 48 connected to the other outlet of the heating diverter 13. It reaches. Note that the refrigerant at the inlet of the heating expansion valve 20 is in a supercritical state while the other refrigerant exiting from the heating diverter 13 is in a supercritical state, and the pressure drops in the process of passing through the heating expansion valve 20, causing the gas / The liquid becomes a two-phase mixed state and flows into the outdoor heat exchanger 23 in this state. Here, the refrigerant whose pressure has dropped in the heating expansion valve 20 evaporates by exchanging heat with the surrounding outside air. Thereafter, the refrigerant that has come out of the outdoor heat exchanger 23 enters the refrigerant introduction pipe 40 from the refrigerant introduction pipe 40B that is connected to the middle portion of the refrigerant pipe 58 via the cooling auxiliary heat exchanger 18 and the cooling diverter 14, and The cycle of being sucked into the first compression element 32, which is the low pressure portion of the compressor 11, is repeated. In addition, since the cooling auxiliary expansion valve 16 is fully closed during the heating operation, the refrigerant flows into the refrigerant pipe 58 connected to the other outlet without being divided by the cooling diverter 14. . Thereby, since the refrigerant does not flow through the cooling auxiliary circuit 75, heat exchange of the refrigerant does not occur in the process of flowing through the passage 18A of the cooling auxiliary heat exchanger 18. Further, since the cooling expansion valve 21 is also fully closed, all of the refrigerant flowing into the refrigerant pipe 58 enters the refrigerant introduction pipe 40B connected to the middle part of the refrigerant pipe 58 and passes through the electromagnetic valve 27. The refrigerant is sucked into the first compression element 32 from the refrigerant introduction pipe 40.

  By the way, when time elapses from the start of the heat source 2 in the heating operation and the temperature of the heat source 2 rises, for example, rises to a predetermined temperature set in advance, the control means operates the compressor 11. To stop. Thereby, heat exchange between the refrigerant and the fluid in the cascade heat exchanger 12 is not performed. Further, the control means controls the three-way valve 8 so that the fluid from the pipe 5A flows into the pipe 5B. Therefore, as shown by the arrow in FIG. 9, the fluid from the circulation pump 5 does not flow to the bypass circuit 7A but flows to the heat source 2 via the pipe 5B. As a result, the fluid is deprived of heat of the heat source 2 and heated, then exits the heat source 2 and enters the pipe 2A, and flows into the heating heat exchanger 4 through the cascade heat exchanger 12 and the pipe 3.

  Here, the fluid is cooled by exchanging heat with the surrounding air. On the other hand, the air heated by exchanging heat with the fluid is blown into the vehicle interior, which is a conditioned room, by the fan 4F, and the vehicle interior is heated. On the other hand, the air cooled by exchanging heat with air in the heating heat exchanger 4 is extracted from the heating heat exchanger 4 and sucked into the circulation pump 5 through the pipe 4 and discharged to the pipe 5A. The cycle that flows to the heat source 2 through the three-way valve 8 and the pipe 5B is repeated.

  Thus, until the heat source 2 is heated to a predetermined temperature set in advance, the compressor 11 is operated, the cascade heat exchanger 12 heats the vehicle interior with heat from the refrigerant in the refrigerant circuit 10, and the heat source 2 After heating, the compressor 11 is stopped and the interior of the vehicle is heated using the waste heat of the heat source 2, so that the interior of the vehicle can be heated early, for example, even immediately after the start of the vehicle. It becomes possible to improve the comfort in the passenger compartment by mounting the air conditioner on the vehicle. In addition, by heating the vehicle interior using the waste heat of the heat source 2 after the heat source 2 is heated, the vehicle interior can be heated without operating the compressor 11, and power consumption can be suppressed as much as possible. Can be heated.

(2) During cooling operation Next, the operation during cooling operation will be described with reference to FIG. In FIG. 10, the arrows indicate the flow of the refrigerant circuit 10 during the cooling operation. During the cooling operation, as shown in FIG. 5, the control means fully closes the heating expansion valve 20, the heating auxiliary expansion valve 15, and the electromagnetic valve 27, and the cooling auxiliary expansion valve 16 and the cooling expansion valve. The opening degree of the refrigerant flowing through the refrigerant 21 is controlled so that the pressure can be reduced. In this case, the circulation pump 5 and the fan 4F are stopped.

  And a control means starts the drive element of the fan 24F of the heat exchanger 24 for cooling, and the compressor 11. FIG. As a result, the low-temperature and low-pressure refrigerant gas is sucked from the refrigerant introduction pipe 40 into the low-pressure chamber side of the first compression element 32 and compressed. Thereby, the refrigerant compressed to the intermediate pressure by the first compression element 32 is discharged into the sealed container 30 from the high pressure chamber side. The refrigerant discharged into the hermetic container 30 merges with the first refrigerant flow from the cooling auxiliary circuit 75 (one refrigerant divided by the cooling diverter 14) in the hermetic container 30.

  Thereafter, the merged refrigerant is sucked into the low-pressure chamber side of the second compression element 34 and compressed to become high-temperature and high-pressure refrigerant gas, enters the refrigerant discharge pipe 42 from the high-pressure chamber side, and is discharged to the outside of the compressor 11. . At this time, the refrigerant is compressed to an appropriate supercritical pressure. The refrigerant gas discharged from the compressor 11 is mixed with oil that has been supplied to the sliding portion of the second compression element 34 of the compressor 11.

  Further, the refrigerant discharged from the refrigerant discharge pipe 42 is the passage 12A of the cascade heat exchanger 12, the refrigerant pipe 43, the passage 17A of the auxiliary heating heat exchanger 17, the refrigerant pipe 45, the heating diverter 13, the refrigerant pipe 48, It flows into the outdoor heat exchanger 23 through the expansion valve 20 for heating. In the cooling operation, since the circulation pump 5 of the waste heat utilization circuit 1 is not operated, heat exchange between the refrigerant and the fluid does not occur in the cascade heat exchanger 12. Further, as described above, the heating auxiliary expansion valve 15 is fully closed, and the refrigerant from the refrigerant pipe 45 does not flow to the heating auxiliary circuit 70, but flows to the refrigerant pipe 48, so in the heating auxiliary heat exchanger 17 The refrigerant flowing in the passage 17A does not radiate heat and flows sequentially to the refrigerant pipe 45, the heating diverter 13, and the refrigerant pipe 48.

  Furthermore, since the heating expansion valve 20 is also fully opened during the cooling operation as described above, the refrigerant flows into the outdoor heat exchanger 23 without being depressurized by the heating expansion valve 20. Then, the refrigerant flowing into the outdoor heat exchanger 23 exchanges heat with the outside air to dissipate the heat, and then exits the outdoor heat exchanger 23 and enters the passage 18A formed on one end side of the cooling auxiliary heat exchanger 18. The cooling auxiliary heat exchanger 18 enters. In the cooling auxiliary heat exchanger 18, the high-pressure side refrigerant flowing through the passage 18A is divided by the low-pressure side refrigerant (cooling flow divider 14) flowing through the passage 18B provided in heat exchange with the passage 18A. Heat is taken away by one refrigerant flowing through the auxiliary circuit 75.

  On the other hand, the refrigerant in the passage 18A cooled by the cooling auxiliary heat exchanger 18 exits the cooling auxiliary heat exchanger 18 from the other end and enters the cooling diverter 14, where the first refrigerant flow ( The refrigerant is divided into two refrigerant streams, one refrigerant) and the second refrigerant stream (the other refrigerant). At this time, since the cooling shunt 14 is configured to fractionate one refrigerant from the upper and lower portions of the shunt 14 as described above, oil is taken out together with the one refrigerant, and the cooling auxiliary circuit 75 is used. Can be shed.

  Then, one refrigerant (one refrigerant and oil) divided by the cooling flow divider 14 enters the cooling auxiliary circuit 75 and reaches the cooling auxiliary expansion valve 16. One refrigerant that has passed through the cooling auxiliary expansion valve 16 is still in a supercritical state, and in this state, the cooling auxiliary is supplied from the inlet of the passage 18B formed at the other end of the cooling auxiliary heat exchanger 18. It flows into the heat exchanger 18 and expands. At this time, the refrigerant (one refrigerant) flowing through the passage 18B takes heat away from the refrigerant flowing through the passage 18B and evaporates.

  In this way, by performing heat exchange with the high-pressure side refrigerant flowing through the passage 18 in the cooling auxiliary heat exchanger 18, the low-pressure side refrigerant (one refrigerant) flowing through the passage 18B can be evaporated. Then, the evaporated low-pressure side refrigerant (including oil) exits the cooling auxiliary heat exchanger 18 from the outlet of the passage 18B formed at one end, enters the refrigerant introduction pipe 41 through the refrigerant pipe 57, and enters the compressor. 11 airtight containers 30. Then, the refrigerant sucked into the sealed container 30 merges with the intermediate pressure refrigerant compressed by the first compression element 32. Further, the oil sucked into the sealed container 30 together with the refrigerant is separated from the refrigerant in the sealed container 30 and returns to the oil sump formed at the bottom. Thereby, the oil discharged to the outside of the compressor 11 can be returned into the sealed container 30.

  In particular, the carbon dioxide refrigerant and oil as described in detail in the heating operation differ greatly in density difference depending on temperature and refrigerant pressure (FIGS. 6 and 7). Therefore, a conventional shunt that shunts one refrigerant from either the upper part or the lower part of the shunt cannot handle such a fluctuation in density difference between the refrigerant and the oil, and the oil with one refrigerant It was difficult to always flow through the auxiliary circuit. Accordingly, the oil cannot be returned to the compressor 11 via the auxiliary circuit, so that the oil in the compressor 11 may be reduced and the oil may be insufficient. In addition, the oil circulates in the refrigerant circuit 10 together with the other refrigerant, so that the oil accumulates in the refrigerant circuit 10, thereby obstructing a good flow of the refrigerant and causing a pressure loss. There was a risk of reducing the performance of the entire apparatus.

  However, by forming the cooling diverter 14 into a shape in which one refrigerant is diverted from the upper part and the lower part, even if the density of the oil is larger or smaller than the density of carbon dioxide, the upper and Oil can be divided from any one of the lower parts, and can be supplied to the cooling auxiliary circuit 75 together with one refrigerant, so that the oil can be reliably returned from the circuit 75 into the sealed container 30 of the compressor 11.

  On the other hand, the other refrigerant (second refrigerant flow) divided by the cooling flow divider 14 is supplied to the cooling expansion valve 21 via the refrigerant pipe 58 connected to the other outlet of the cooling flow divider 14. It reaches. Note that the refrigerant at the inlet of the cooling expansion valve 21 is in a supercritical state while the other refrigerant exiting from the cooling diverter 14 is reduced in pressure in the process of passing through the cooling expansion valve 21, and the gas / The liquid becomes a two-phase mixed state, and flows into the cooling heat exchanger 24 in this state. Here, the refrigerant whose pressure is reduced by the cooling expansion valve 21 evaporates by exchanging heat with the surrounding air, and the surrounding air is cooled by the endothermic effect at this time. The cooled air is blown into the vehicle interior by the fan 24F and cools the interior of the vehicle.

  On the other hand, the refrigerant that has exited the cooling heat exchanger 24 enters the refrigerant introduction pipe 40 from the refrigerant introduction pipe 40 </ b> A, and repeats the cycle of being sucked into the first compression element 32 that is the low-pressure portion of the compressor 11.

  In this way, the refrigerant circulating in the refrigerant circuit 10 is returned by returning one refrigerant, which has been diverted by the cooling diverter 14 during the cooling operation, into the hermetic container 30 that is the intermediate pressure portion of the compressor 11. Without increasing the amount, the amount of refrigerant sucked into the second compression element 34 and compressed and flowing to the outdoor heat exchanger 23 can be increased. As a result, the amount of refrigerant that exchanges heat with the fluid in the outdoor heat exchanger 23 increases, and the heat exchange capability of the outdoor heat exchanger 23 can be improved. Further, the refrigerant radiated by the outdoor heat exchanger 23 is caused to flow to the cooling auxiliary heat exchanger 18, and the refrigerant before being diverted by the cooling diverter 14 and one refrigerant diverted by the cooling diverter 14. As a result, the refrigerant cooled by the outdoor heat exchanger 23 can be further cooled.

  In particular, in the present invention, the refrigerant flowing through the passage 18B of the cooling auxiliary heat exchanger 18 of the refrigerant circuit 10 still remains in a supercritical state. That is, since the capacity of the cooling auxiliary heat exchanger 18 is proportional to the temperature difference, in the supercritical condition, the temperature before entering the cooling expansion valve 21 is lowered to generate a low temperature. It is advantageous for the capacity. As a result, it is possible to improve the heat dissipating capacity more compactly and at a lower cost than a heat exchanger that exchanges heat between conventional refrigerant and air.

  In this way, after the refrigerant radiated by the outdoor heat exchanger 23 is further cooled by the auxiliary cooling heat exchanger 18, it is adiabatically expanded by the cooling heat exchanger 24, so that the cooling heat exchanger 24. The specific enthalpy of the refrigerant entering can be reduced, and the effect of being able to generate a lower temperature in the cooling heat exchanger 24 is obtained. Thereby, the freezing effect in the heat exchanger 24 for cooling can be improved.

  In particular, the amount of refrigerant compressed by the first compression element 32 of the compressor 11 by returning one refrigerant divided by the cooling flow divider 14 into the hermetic container 30 that is an intermediate pressure portion of the compressor 11. Therefore, the compression power of the compressor 11 can be suppressed and the operation efficiency can be improved.

  FIG. 11 shows a cooling capacity characteristic when the vehicle interior is cooled using the refrigerant circuit 10 of the present embodiment and a cooling capacity characteristic when the vehicle interior is cooled using a conventional refrigerant circuit. In FIG. 11, black circles indicate the cooling characteristics of the conventional air conditioner, and black squares indicate the cooling characteristics of the air conditioner of the present invention. Further, the triangle indicates the ratio of the cooling characteristic of the present invention to the conventional cooling capacity characteristic (heating characteristic of the air conditioner of the present invention / heating characteristic of the conventional air conditioner).

  As is apparent from FIG. 11, it can be seen that the application of the present invention improves the cooling capacity over the conventional air conditioner. In particular, as shown by the triangle in the figure (cooling characteristics of the air conditioner of the present invention / cooling characteristics of the conventional air conditioner), the outlet temperature of the outdoor heat exchanger 23 is higher, and the more severe the condition during cooling, It can be seen that the air conditioner to which the present invention is applied can obtain a greater effect.

  As described above, according to the present invention, the efficiency and performance of an air conditioner using a carbon dioxide refrigerant can be improved.

(3) During dehumidifying operation By the way, if the humidity in the passenger compartment increases, the windshield may become cloudy and the visibility may deteriorate, which may hinder driving. Therefore, it is necessary to dehumidify the passenger compartment. Next, operation during such dehumidifying operation will be described. During the dehumidifying operation, the control means fully closes the heating expansion valve 20, the heating auxiliary expansion valve 15, and the electromagnetic valve 27 so that the refrigerant flows as shown by the arrows in FIG. 10 as in the cooling operation. At the same time, the degree of opening of the refrigerant flowing through the cooling auxiliary expansion valve 16 and the cooling expansion valve 21 is controlled so that the pressure can be reduced (FIG. 5). The air in the passenger compartment passes through the heating heat exchanger 4 through an air circulation duct (not shown) from the passenger compartment, and passes through the cooling heat exchanger 24 to be repeatedly circulated into the passenger compartment. .

  During the dehumidifying operation, the control means operates the circulation pump 5 to circulate the fluid in the waste heat utilization circuit 1, and also operates the fan 4F of the indoor heat exchanger 4. In this case, when the temperature of the heat source 2 is low, such as immediately after the start of the heat source 2 as described above, the three-way valve 8 is controlled so that the fluid from the pipe 5A flows into the bypass pipe 7A. For example, when the heat source 2 rises to a predetermined temperature set in advance, the three-way valve 8 is controlled by the control means so that the fluid from the pipe 5A flows into the pipe 5B.

  As a result, the fluid flowing through the cascade heat exchanger 12 or the waste heat utilization circuit 1 heated by the heat source 2 exchanges heat with ambient air in the heating heat exchanger 4 to radiate heat. The air heated by removing heat from the fluid is sent to the cooling heat exchanger 24 of the refrigerant circuit 10 by the fan 4F. At this time, moisture (humidity) contained in the air from the passenger compartment is condensed on the surface of the cooling heat exchanger 24 in the process of passing through the cooling heat exchanger 24 and falls as water droplets. Thereby, moisture (humidity) contained in the air can be removed.

  The air from which moisture has been removed by the cooling heat exchanger 24 repeats a cycle in which the air is blown into the passenger compartment by the fan 24F. Thereby, the humidity in the passenger compartment gradually decreases, and the above-described fogging of the windshield can be effectively taken.

  In the refrigerant circuit 10 of the air conditioner described in detail above, when the two compression elements are driven by one drive shaft as the compressor 11 as in this embodiment, the first compression element 32 and the second compression element The pressure (intermediate pressure) of the intermediate pressure portion is determined by the product of the excluded volume ratio 34 and the volume efficiency 34 and the pressure and temperature conditions of the intake refrigerant of the first compression element 32. In the refrigerant circuit 10 of the present embodiment, the mass flow rate (refrigerant amount) of one refrigerant flowing through the passage 18B of the auxiliary cooling heat exchanger 18 of the auxiliary cooling circuit 75 that achieves the highest efficiency during the cooling operation is the cooling heat. 40% or more and 60% or less of the other refrigerant flowing through the exchanger 24. In order to achieve this, the excluded volume ratio of the first compression element 32 and the second compression element 34 is 70% or more and 85% or less. Therefore, when the ratio of the second compression element 34 to the excluded volume of the first compression element 32 is set to 70% or more and 85% or less, the maximum efficiency can be achieved.

(4) Control of auxiliary pressure reducing device Furthermore, in order to operate efficiently in the above-described air conditioner, the current is diverted by a shunt (heating diverter 13 or cooling auxiliary circuit 14), and the auxiliary circuit (heating auxiliary) The refrigerant 70 flowing into the circuit 70 or the cooling auxiliary circuit 75) is controlled to reduce the specific enthalpy of the refrigerant entering the outdoor heat exchanger 23 during the heating operation and to the cooling heat exchanger during the cooling operation. The specific enthalpy of the refrigerant entering 24 needs to be reduced.

  Therefore, it is necessary to detect the refrigerant pressure and temperature and perform control based on them by detecting the refrigerant pressure and temperature. However, the detection of the refrigerant pressure is more costly than the temperature detection. In particular, in the case of a carbon dioxide refrigerant whose pressure becomes very high due to compression, the performance and reliability of the pressure detection means itself, and other mounting parts of the pressure detection means There was a big problem in use including reliability.

  Therefore, in the air conditioner of the present embodiment, the control means controls one refrigerant and the other refrigerant flowing in the auxiliary circuit (the heating auxiliary circuit 70 or the cooling auxiliary circuit 75) based on the refrigerant temperature in the refrigerant circuit 10. The amount shall be controlled. FIG. 12 shows the circulation rate of one refrigerant flowing in the auxiliary circuit (heating auxiliary circuit 70 or cooling auxiliary circuit 75) (one refrigerant amount G2 divided by the flow divider 13 or the flow divider 14 and the other refrigerant amount G1). This shows the change in temperature and coefficient of performance (COP) of each part when the ratio (G2 / G1)) is changed. In FIG. 12, a solid line A is a coefficient of performance during heating operation, a broken line B is a coefficient of performance during cooling operation, a solid line C is a refrigerant gas temperature discharged from the compressor 11, and a solid line D is an intermediate pressure portion of the compressor 11. The refrigerant temperature in the sealed container 30 (second stage intake temperature), the solid line E is the refrigerant temperature (before the expansion valve) entering the main decompression device (the heating expansion valve 20 during the heating operation, the cooling expansion valve 21 during the cooling operation). Temperature).

  As shown in FIG. 12, when the circulation rate of the refrigerant flowing through the auxiliary circuit is from 0% to about 20%, the main decompression device (the heating expansion valve 20 during the heating operation, The refrigerant temperature entering the cooling expansion valve 21) during the cooling operation (temperature before the expansion valve) decreases, and the intermediate pressure portion refrigerant temperature increases. When the refrigerant amount reaches about 20%, the refrigerant temperature entering the main pressure reducing device (the heating expansion valve 20 during the heating operation and the cooling expansion valve 21 during the cooling operation) becomes the lowest value, and the refrigerant temperature of the intermediate pressure portion Is the highest value. At this time, the coefficient of performance (COP) during the heating operation is the best value. Also, the coefficient of performance during the cooling operation is a good value with almost no change from 0% to about 20%.

  However, when the circulation rate of the refrigerant flowing through the auxiliary circuit exceeds 20%, the refrigerant temperature (pre-expansion valve temperature) entering the main decompression device (the heating expansion valve 20 during the heating operation and the cooling expansion valve 21 during the cooling operation). ) Gradually increases, and the refrigerant temperature in the intermediate pressure portion also gradually decreases. Moreover, it turns out that the coefficient of performance at the time of heating operation and at the time of cooling operation will also fall if it exceeds 20%. This is because the amount of the refrigerant flowing through the auxiliary circuit is too large, and the auxiliary heat exchanger (the heating auxiliary heat exchanger 17 during the heating operation and the cooling auxiliary heat exchanger 18 during the cooling operation) has a high pressure side refrigerant and heat. This is thought to be because a surplus that cannot be exchanged occurs.

  Thus, the refrigerant amount (circulation rate) at which the refrigerant temperature (temperature before the expansion valve) entering the main decompression device (the heating expansion valve 20 during the heating operation and the cooling expansion valve 21 during the cooling operation) becomes the minimum value is obtained. Since the refrigerant amount at which the refrigerant temperature in the intermediate pressure portion reaches the maximum value coincides and the coefficient of performance (COP) at this time becomes a good value, in order to operate the air conditioner more efficiently, the control means The opening degree of the auxiliary pressure reducing device (the heating auxiliary expansion valve 15 during the heating operation and the cooling auxiliary expansion valve 16 during the cooling operation) is controlled as follows.

  That is, during the heating operation, the control means determines the refrigerant temperature detected by the refrigerant temperature sensor 48S based on the temperature of the refrigerant entering the heating expansion valve 20 detected by the refrigerant temperature sensor 48S. Based on the refrigerant temperature in the hermetic container 30 which is the lowest value and detected by the refrigerant temperature sensor 30S, which is the intermediate pressure part of the compressor 11, the refrigerant temperature detected by the refrigerant temperature sensor 30S is set to the refrigerant circuit 10. The opening degree of the auxiliary heating expansion valve 15 is controlled so as to be the highest value.

  Further, during the cooling operation, the control device, based on the refrigerant temperature entering the cooling expansion valve 21 detected by the refrigerant temperature sensor 58S, has the lowest refrigerant temperature detected by the refrigerant temperature sensor 58S, and Based on the refrigerant temperature in the sealed container 30 that is the intermediate pressure part of the compressor 11 detected by the refrigerant temperature sensor 30S, the cooling is performed so that the refrigerant temperature detected by the refrigerant temperature sensor 30S becomes the maximum value. The opening degree of the auxiliary expansion valve 16 is controlled.

  Thus, by controlling the heating auxiliary expansion valve 15 and the cooling auxiliary expansion valve 16, the coefficient of performance (COP) becomes a good value as shown in FIG. Thus, the efficiency can be further improved by controlling the air conditioner at a low cost.

It is a schematic diagram of the air conditioning apparatus of one Example of this invention. It is a figure which shows the structure of the flow shunt of the refrigerant circuit of the air conditioning apparatus of FIG. It is a figure which shows the structure of another shunt. It is a figure which shows the flow of the refrigerant | coolant and the fluid at the time of the heating operation of the air conditioning apparatus of FIG. It is a figure which shows operation | movement of the expansion valve and electromagnetic valve of the refrigerant circuit of FIG. It is the figure which showed the density accompanying the temperature change of a carbon dioxide refrigerant and oil (PAG). It is the figure which showed the density accompanying the temperature change of a carbon dioxide refrigerant and oil (PVE). It is a figure which shows the heating capability characteristic of the air conditioning apparatus of this invention, and the conventional air conditioning apparatus. It is a figure which shows the flow of the fluid at the time of the heating operation after the heat source heating of the air conditioning apparatus of FIG. It is a figure which shows the flow of the refrigerant | coolant at the time of the cooling operation of the air conditioning apparatus of FIG. It is a figure which shows the air conditioning apparatus of this invention, and the air_conditioning | cooling capability characteristic of the conventional air conditioning apparatus. It is a figure which shows each part temperature and a coefficient of performance accompanying the change of the circulation rate of the refrigerant | coolant which flows through an auxiliary circuit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Waste heat utilization circuit 2 Heat source 4 Heating heat exchanger 5 Circulation pump 10 Refrigerant circuit 11 Compressor 12 Cascade heat exchanger 13, 14 Divider 15, 16 Auxiliary decompression device 17 Internal heat exchanger 20, 21 Main decompression device 23 Heat absorber (outdoor heat exchanger)
24 Heat exchanger for cooling 30 Airtight container 32 First compression element 34 Second compression element 70, 75 Auxiliary circuit 30S, 41S, 47S, 48S, 58S Refrigerant temperature sensor

Claims (8)

A fluid is circulated between the heat source and the heating heat exchanger, and the waste heat utilization circuit for using the waste heat of the heat source for heating the conditioned room in the heating heat exchanger, and carbon dioxide as a refrigerant. A refrigerant circuit having a supercritical pressure on the high-pressure side, and a cascade heat exchanger for exchanging heat between the fluid flowing from the heat source to the heat exchanger for heating and the refrigerant in the refrigerant circuit in the waste heat utilization circuit,
The refrigerant circuit includes a compressor, the cascade heat exchanger, a flow divider, an auxiliary pressure reducing device, an internal heat exchanger, a main pressure reducing device, and a heat absorber provided outside the conditioned room, and is discharged from the compressor. The refrigerant flowing out of the cascade heat exchanger, the refrigerant flowing out of the cascade heat exchanger is diverted by the diverter, and one of the refrigerants is made to flow from the auxiliary pressure reducing device to the internal heat exchanger to be converted into the cascade heat. After exchanging heat with the refrigerant that has come out of the exchanger, the refrigerant is sucked into the intermediate pressure portion of the compressor, and the other refrigerant that has been divided is passed from the main decompressor to the heat absorber, and then the low pressure of the compressor An air conditioner characterized by being sucked into a part. A fluid is circulated between the heat source and the heating heat exchanger, and the waste heat utilization circuit for using the waste heat of the heat source for heating the conditioned room in the heating heat exchanger, and carbon dioxide as a refrigerant. A refrigerant circuit having a supercritical pressure on the high-pressure side, and a cascade heat exchanger for exchanging heat between the fluid flowing from the heat source to the heat exchanger for heating and the refrigerant in the refrigerant circuit in the waste heat utilization circuit,
The refrigerant circuit includes a compressor, the cascade heat exchanger, a shunt, an auxiliary pressure reducing device, an internal heat exchanger, a main pressure reducing device, and a cooling heat exchanger for cooling the conditioned room, and the compression circuit The refrigerant discharged from the machine is caused to flow to the cascade heat exchanger, the refrigerant that has left the cascade heat exchanger is diverted by the diverter, and one refrigerant is allowed to flow from the auxiliary pressure reducing device to the internal heat exchanger. Heat exchange with the refrigerant after exiting from the cascade heat exchanger, and then sucked into the intermediate pressure portion of the compressor, and the other divided refrigerant was allowed to flow from the main decompression device to the cooling heat exchanger. Thereafter, the air conditioner is sucked into a low pressure portion of the compressor. A fluid is circulated between the heat source and the heating heat exchanger, and the waste heat utilization circuit for using the waste heat of the heat source for heating the conditioned room in the heating heat exchanger, and carbon dioxide as a refrigerant. A refrigerant circuit having a supercritical pressure on the high-pressure side, and a cascade heat exchanger for exchanging heat between the fluid flowing from the heat source to the heat exchanger for heating and the refrigerant in the refrigerant circuit in the waste heat utilization circuit,
The refrigerant circuit is for cooling a compressor, the cascade heat exchanger, a shunt, an auxiliary pressure reducing device, an internal heat exchanger, a main pressure reducing device, a heat absorber provided outside the conditioned room, and the conditioned room. A cooling heat exchanger, the refrigerant discharged from the compressor is allowed to flow to the cascade heat exchanger, the refrigerant that has exited the cascade heat exchanger is diverted by the flow divider, and one of the refrigerants is the auxiliary After flowing from the decompression device to the internal heat exchanger and exchanging heat with the refrigerant after exiting from the cascade heat exchanger, the refrigerant is sucked into the intermediate pressure portion of the compressor, and the other refrigerant divided during heating is After flowing from the main pressure reducing device to the heat absorber, the refrigerant is sucked into the low pressure portion of the compressor, and the other refrigerant separated during cooling is flowed from the main pressure reducing device to the cooling heat exchanger. Inhale into the low pressure part An air conditioning apparatus characterized by and.   The internal heat exchanger exchanges heat between the one refrigerant that has passed through the auxiliary pressure reducing device and the refrigerant that has exited the cascade heat exchanger and has not been divided by the flow divider. The air conditioner according to any one of claims 1 to 3.   The air conditioner according to any one of claims 1 to 4, wherein the one refrigerant is divided from an upper part and a lower part of the flow divider.   The compressor includes a low-stage compression unit and a high-stage compression unit, and the refrigerant discharged from the heat absorber or the heat exchanger for cooling is sucked into the low-stage compression unit, and the low-stage compression unit The compressed intermediate pressure refrigerant is sucked into the high stage compression means together with the one refrigerant exiting the internal heat exchanger, and the high stage compression means with respect to the excluded volume of the low stage compression means An air conditioner in which the ratio of the excluded volume is 70% or more and 85% or less.   The temperature detecting means for detecting the temperature of the refrigerant entering the main pressure reducing device is provided, and the opening degree of the auxiliary pressure reducing device is controlled so that the temperature detected by the temperature detecting means becomes a minimum value. The air conditioning apparatus according to any one of claims 1 to 6.   Temperature detecting means for detecting the temperature of the refrigerant in the intermediate pressure portion of the compressor is provided, and the opening of the auxiliary pressure reducing device is controlled so that the temperature detected by the temperature detecting means becomes the maximum value. The air conditioning apparatus according to any one of claims 1 to 7.

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