JP2010043556A - Expander unit and refrigeration cycle device including the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an expander unit automatically adjusting the difference between the flow rate of refrigerant flowing in a sub compressor and the flow rate of refrigerant that can be sucked while materializing a compact structure, and a reliable and efficient refrigeration cycle device capable of operating under a wide range of conditions by incorporating the expander unit. <P>SOLUTION: The expander unit 1 includes a bypass port 361f providing communication between a sub compression delivery space 370 and at least one of a suction chamber 374 and a sub compression chamber 363, and a bypass check valve 331 controlling communication/shut-off of the bypass port 361f in a closed vessel 310. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an expander unit that recovers expansion power generated during expansion of a refrigerant and uses the expansion power to compress the refrigerant, and a refrigeration cycle apparatus including the expander unit, and particularly in the expander unit. The present invention relates to a built-in sub-compressor bypass structure.

  Conventionally, there is a refrigeration cycle apparatus including an expander unit that recovers expansion power generated during expansion of a refrigerant and uses the expansion power to compress the refrigerant. In such a refrigeration cycle apparatus, a bypass pipe for adjusting the flow rate of the refrigerant flowing into the sub compressor is provided outside the container of the expander unit that houses the sub compression mechanism and the expansion mechanism. A bypass check valve that restricts refrigerant flow between the pipe and the discharge pipe is often provided (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 11-94379 (page 3, FIG. 1)

  In the refrigeration cycle apparatus as described above, a space for providing the bypass pipe and the bypass check valve has to be secured outside the expander unit, and there is a problem that the apparatus becomes large. Also, in such a refrigeration cycle, when the amount of refrigeration oil discharged from the main compressor together with the refrigerant gas is large, the heat exchange performance is reduced due to the refrigeration oil mixed in the refrigerant, The refrigeration oil is taken out to the outside, and there is a possibility that the sliding portion inside the main compressor is not sufficiently supplied with oil and the sliding portion is seized.

  The present invention has been made to solve the above problems, and can automatically adjust the deviation between the flow rate of refrigerant flowing into the sub compressor and the flow rate of refrigerant that can be sucked, while realizing a compact structure. It is an object of the present invention to provide an expander unit and a refrigeration cycle apparatus that is capable of a wide range of operating conditions by providing the expander unit, has high reliability, and is highly efficient.

  The expander unit according to the present invention accommodates an expander that recovers expansion power during decompression of the refrigerant and a sub-compressor that compresses the refrigerant using the expansion power in a sealed container, and supplies the sub-compressor with the expander unit. A sub-compressor suction pipe that sucks the refrigerant and a sub-compressor discharge pipe that discharges the refrigerant compressed by the sub-compressor and communicates with the inside of the sealed container, and is formed in the sub-compressor. A sub-compression chamber for compressing refrigerant; a suction chamber formed in the sub-compressor and extending from the sub-compressor suction pipe to the sub-compression chamber; and the sub-compression chamber; A sub-compressor discharge port that discharges the generated refrigerant, a discharge chamber that is formed in the sub-compressor and from which the refrigerant is discharged from the sub-compressor discharge port, and is provided in the sealed container. Refrigerant A sub-compression discharge space, an oil reservoir space that is formed in the sealed container and stores lubricating oil, passes through the sub-compressor and the expander, and communicates the sub-compression discharge space and the oil reservoir space. An oil return hole, a bypass port provided in the sealed container and communicating at least one of the suction chamber or the sub compression chamber and the sub compression discharge space, and provided in the sealed container, the bypass port And a bypass on-off valve for opening and closing the valve.

  A refrigeration cycle apparatus according to the present invention includes the expander unit, a main compressor, an outdoor heat exchanger, and an indoor heat exchanger, and configures the main compressor and the expander unit. The sub-compressor, the outdoor heat exchanger, the expander constituting the expander unit, and the indoor heat exchanger are connected in series during cooling operation.

  According to the expander unit of the present invention, the bypass port and the on-off valve for bypassing are provided in the sealed container, so that a compact structure can be achieved without increasing the size. Further, according to the expander unit, the bypass on / off valve can automatically bypass the refrigerant corresponding to the excessive flow rate flowing into the sub compressor.

  According to the refrigeration cycle apparatus according to the present invention, by providing the expander unit, the refrigeration cycle apparatus can be made compact, and a wide range of operating conditions are possible, and the reliability is high and the efficiency is high. Can do. Further, according to the refrigeration cycle apparatus, the expander unit can function as an oil separator.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Embodiment 1 FIG.
FIG. 1 is a longitudinal sectional view showing a configuration of an expander unit 1 according to Embodiment 1 of the present invention. Based on FIG. 1, the structure of the expander unit 1 is demonstrated. This expander unit 1 is an integrated scroll-type expander and compressor, and has a function of recovering expansion power generated when the refrigerant expands and compressing the refrigerant using the recovered expansion power. It is what. In addition, in the following drawings including FIG. 1, the relationship of the size of each component may be different from the actual one. Further, in the following drawings including FIG. 1, the same reference numerals denote the same or equivalent parts, and this is common throughout the entire specification.

  The expander unit 1 includes an expander 1a and a sub compressor 1b. The expander 1a and the sub-compressor 1b are housed in a sealed container 310. The sealed container 310 is a pressure container. As shown in FIG. 1, the sub compressor 1 b is disposed on the upper side of the sealed container 310, and the expander 1 a is disposed on the lower side of the sealed container 310. An oil sump space 372 for storing lubricating oil 318 such as refrigerating machine oil is formed in the inner lower portion of the sealed container 310. In addition, a sub-compression discharge space 370 in which the refrigerant compressed by the sub-compressor 1b is discharged is formed in the upper part inside the sealed container 310.

  Further, in the sealed container 310, an expander suction pipe 313 for sucking the refrigerant into the expander 1a, an expander discharge pipe 315 for discharging the refrigerant from the expander 1a, and a refrigerant sucked into the sub compressor 1b. A sub-compressor suction pipe 312 and a sub-compressor discharge pipe 314 for discharging refrigerant from the sub-compressor 1b are provided. The sub-compressor suction pipe 313 and the expander discharge pipe 315 communicate with the expander 1a from the side surface of the sealed container 310 on the outer peripheral side of the expander 1a. The sub compressor discharge pipe 314 is provided so as to communicate with the sub compression discharge space 370 from the side surface of the hermetic container 310 on the outer peripheral side of the sub compression discharge space 370 so as to communicate with the compressor 1b.

  In addition, an oil pipe 380 that supplies lubricating oil 318 to be stored in the oil sump space 372 from the main compressor 5 (described in Embodiment 2) is provided in the airtight container 310 from the bottom surface of the airtight container 310. It is provided so that it may communicate with. The oil pipe 380 communicating with the oil sump space 372 is connected to the main compressor 5, and the position of the tip portion on the oil sump space 372 side is lubricated so as to be stored in the main compressor 5 and the oil sump space 372. The oil 318 is provided at a position higher than the appropriate oil level.

  The expander 1a decompresses and expands the refrigerant sucked from the expander suction pipe 313, and discharges the refrigerant from the expander discharge pipe 315. The expander 1 a includes an expander fixed scroll 351 and an expander swing scroll 352. As shown in FIG. 1, the expander fixed scroll 351 is disposed on the lower side, and the expander swing scroll 352 is disposed on the upper side. A spiral 351 s that is a spiral projection is provided upright on one surface of a base plate 351 a constituting the fixed scroll 351 for the expander. Further, a spiral 352 s that is a spiral projection is provided upright on one surface of a base plate 352 a that constitutes the swing scroll 352 for the expander.

  The expander fixed scroll 351 and the expander swing scroll 352 are arranged so that the spiral 351s and the spiral 352s mesh with each other. The expansion chamber 353 whose volume changes relatively is formed by the spiral 351s and the spiral 352s. Further, a tip seal 354 for partitioning the expansion chamber 353 is attached to the distal ends of the spiral 351s and the spiral 352s. Furthermore, an expander suction port 351d for sucking refrigerant from the expander suction pipe 313 is formed in the base plate 351a constituting the expander fixed scroll 351 so as to be connected to the expander suction pipe 313. It has become.

  The sub compressor 1b compresses the refrigerant sucked from the sub compressor suction pipe 312 and discharges it from the sub compressor discharge pipe 314. The sub compressor 1b has a sub compressor fixed scroll 361 and a sub compressor swing scroll 362. As shown in FIG. 1, the sub-compressor fixed scroll 361 is disposed on the upper side, and the sub-compressor swing scroll 362 is disposed on the lower side. A spiral 361 s that is a spiral projection is provided upright on one surface of a base plate 361 a that constitutes the fixed compressor scroll 361. Further, a spiral 362 s that is a spiral projection is provided upright on one surface of a base plate 362 a that constitutes the sub-compressor swing scroll 362.

  The sub-compressor fixed scroll 361 and the sub-compressor swing scroll 362 are arranged so that the spiral 361 s and the spiral 362 s mesh with each other. The sub-compression chamber 363 whose volume changes relatively is formed by the spiral 361s and the spiral 362s. Further, a tip seal 364 for partitioning the sub compression chamber 363 is attached to the distal ends of the spiral 361s and the spiral 362s. Further, the base plate 361a constituting the sub compressor fixed scroll 361 includes a sub compressor suction port 361d for sucking refrigerant from the sub compressor suction pipe 312 and a discharge chamber formed in the base plate 361a. A sub compressor discharge port 361e for discharging the refrigerant to 361g and a bypass port 361f for bypassing the sucked refrigerant to the bypass check valve chamber 361h are formed.

  The sub compressor suction port 361d is formed to be connected to the sub compressor suction pipe 312. A discharge valve 330 is provided at the distal end of the sub compressor discharge port 361e on the discharge chamber 361g side. The discharge valve 330 opens and closes to communicate / block the sub compressor discharge port 361e and the discharge chamber 361g. The refrigerant discharged from the sub compressor discharge port 361e reaches the sub compression discharge space 370 after passing through the discharge chamber 361g.

  A bypass check valve 331 is provided at the tip of the bypass port 361f on the bypass check valve chamber 361h side. The bypass check valve 331 functions as a bypass on-off valve, and opens and closes to communicate / block the bypass port 361f and the bypass check valve chamber 361h. The refrigerant bypassed to the bypass port 361f reaches the sub compression discharge space 370 after passing through the bypass check valve chamber 361h.

  In order to prevent refrigerant from leaking from the sub compressor 1b, an outer peripheral seal 365 is provided between the sub compressor fixed scroll 361 and the sub compressor swing scroll 362. The outer peripheral seal 365 is a wall surface on the outermost peripheral side of the suction chamber 374 formed between the sub-compressor fixed scroll 361 and the sub-compressor swing scroll 362, and is connected to the sub-compressor fixed scroll 361. The suction chamber 374 and the orbiting scroll motion space 371 are hermetically sealed. The suction chamber 374 serves as a refrigerant passage from the sub compressor suction pipe 312 to the sub compression chamber 363.

  A shaft 308 passes through the center of the expander fixed scroll 351, the expander swing scroll 352, the sub compressor lock scroll 361, and the sub compressor swing scroll 362. The spiral 352s of the expander swing scroll 352 and the spiral 362s of the sub-compressor swing scroll 362 are configured integrally by sharing a back-to-back structure or a base plate. An Oldham ring 307 is provided between the sub-compressor fixed scroll 361 and the sub-compressor orbiting scroll 362 to restrict the revolving motion during the revolving motion of the orbiting scroll and enable the revolving motion. ing.

  A balance weight 309a is provided at the upper end of the shaft 308, and a balance weight 309b is provided at the lower end. The balance weight 309a and the balance weight 309b are for adjusting the balance when the shaft 308 is rotated, and the material, size, shape, and the like are not particularly limited. The shaft 308 is supported by the expansion mechanism side bearing portion 351b and the sub compression mechanism side bearing portion 361b. In addition, a crank portion that eccentrically drives the orbiting scroll is provided at the center of the orbiting scroll 352 for the expander and the orbiting scroll 362 for the sub compressor (hereinafter, simply referred to as the orbiting scroll). 308b is provided.

  An oil supply pump 306 for pumping up the lubricating oil 318 stored in the oil sump space 372 is attached to the lower end of the shaft 308. The lubricating oil 318 pumped up by the oil supply pump 306 is supplied to the expansion mechanism side bearing portion 351b and the sub compression mechanism side bearing portion 361b through the oil supply hole 308c formed in the shaft 308. . Further, an oil return is provided in the outer peripheral portion of the expander fixed scroll 351 and the sub compressor fixed scroll 361 so as to pass through the sub compressor 1b and the expander 1a to communicate the sub compression discharge space 370 and the oil sump space 372. A hole 317 is formed. The oil return hole 317 is formed so as not to pass through the orbiting scroll motion space 371 (a space for enabling the orbiting scroll to revolve), and the lubricating oil 318 in the sub-compression discharge space 370 can be used as oil. It returns to the reservoir space 372.

  FIG. 2 is a plan view showing a configuration of the sub compressor 1b. FIG. 2 is a cross-sectional view of the expander unit 1 shown in FIG. However, in FIG. 2, the shaft 308 is omitted. Based on FIG. 2, the state which combined the spiral 361s and the spiral 362s of the sub compressor 1b is demonstrated in detail. As described with reference to FIG. 1, the sub-compressor 1 b meshes the spiral 361 s of the sub-compressor fixed scroll 361 and the spiral 362 s of the sub-compressor orbiting scroll 362 with each other, and the sub-compressor has a relatively variable volume. A compression chamber 363 is formed.

  As shown in FIG. 2, the sub compressor suction port 361d and the bypass port 361f are formed at positions that do not interfere with the spiral 362s located on the outermost periphery of the sub compressor swing scroll 362. A space surrounded by the outermost peripheral wall of the sub-compression chamber 363 and the outer peripheral seal 365 provided between the sub-compressor fixed scroll 361 and the sub-compressor swinging scroll 362 is the sub-compressor 1b. A suction chamber 374 is formed. The outer peripheral seal 365 is formed in an annular shape such as an O-ring, and is provided between the sub-compressor fixed scroll 361 and the sub-compressor swing scroll 362.

Here, operation | movement of the expander unit 1 is demonstrated easily based on FIG.1 and FIG.2.
In the sub compressor 1b, the refrigerant flowing from the sub compressor suction pipe 312 is supplied to the sub compression chamber 363 via the sub compressor suction port 361d and the suction chamber 374, and is balanced with the power recovered by the expander 1a. Compressed through the sub compressor discharge port 361e and the discharge chamber 361g, passes through the sub compression discharge space 370, and is discharged from the sub compressor discharge pipe 314. In the compression stroke, the driving force generated in the expander 1a is directly transmitted to the sub-compressor 1b through the expander swing scroll 352 and the sub-compressor swing scroll 362 that are integrally formed. The compressor rocking scroll 362 revolves to compress the refrigerant by gradually reducing the volume of the sub-compression chamber 363.

  On the other hand, in the expander 1a, the refrigerant that has flowed from the expander suction pipe 313 is supplied to the expansion chamber 353 via the expander suction port 351d, is decompressed, and passes from the expander discharge pipe 315 via the orbiting scroll motion space 371. Discharged. In the expansion stroke, the high-pressure refrigerant sucked into the expansion chamber 353 generates expansion power corresponding to the pressure difference from the rocking scroll motion space 371 that becomes low pressure, and the volume of the expansion chamber 353 is expanded by the generated expansion power. The expander orbiting scroll 352 is caused to revolve in the direction of the rotation. Thus, in the expander unit 1, the expansion power generated when the refrigerant is decompressed by the expander 1a is recovered, and the refrigerant is compressed by the sub compressor 1b using the expansion power.

  FIG. 3 is a longitudinal sectional view for explaining the flow of the refrigerant gas and the lubricating oil 318 in the sub compressor 1b when there is a high and low pressure difference in the sub compressor 1b. FIG. 4 is a longitudinal sectional view for explaining an example of the flow of the refrigerant gas and the lubricating oil 318 in the sub compressor 1b when there is no high / low pressure difference in the sub compressor 1b. FIG. 5 is a longitudinal sectional view for explaining another example of the flow of the refrigerant gas and the lubricating oil 318 in the sub compressor 1b when there is no high / low pressure difference. Based on FIGS. 3-5, the refrigerant | coolant of the expander unit 1 and the flow of the lubricating oil 318 are demonstrated in detail. First, the operation when the high and low pressure difference is generated in the sub compressor 1b will be described based on FIG. 3, and then the high and low pressure difference is not generated in the sub compressor 1b based on FIGS. The operation will be described. 3 to 5, white arrows indicate the flow of the refrigerant, and black arrows indicate the flow of the lubricating oil.

[With high and low pressure difference]
First, the flow of the refrigerant (the white arrow shown in FIG. 3) will be described. The high-pressure refrigerant that has flowed into the expander 1a is expanded through the expansion chamber 353. At this time, power is generated. Then, the refrigerant expanded and depressurized in the expansion chamber 353 is discharged from the expander discharge pipe 315 to the outside of the sealed container 310 via the orbiting scroll motion space 371. The refrigerant flowing into the sub compressor 1b from the sub compressor suction pipe 312 passes through the sub compression chamber 363 and is compressed and boosted by the expansion power generated in the expander 1a.

  The refrigerant compressed and pressurized in the sub-compression chamber 363 is once discharged into the sub-compression discharge space 370 in the sealed container 310 and then discharged from the sub-compressor discharge pipe 314 to the outside of the sealed container 310. At this time, since the orbiting scroll motion space 371 and the sub-compressor 1b are sealed by the outer peripheral seal 365, the inside of the orbiting scroll motion space 371 has a post-expansion pressure. On the other hand, in the oil sump space 372, the pressure after compression of the sub compressor 1 b is the same as that of the sub compression discharge space 370 through the oil return hole 317 that does not pass through the orbiting scroll motion space 371. Note that the bypass check valve 331 is closed due to the high and low pressure difference of the sub compressor 1b.

  Next, the flow of the lubricating oil 318 (black arrows shown in FIG. 3) will be described. The lubricating oil 318 is circulated with the refrigerant gas in the sub compressor 1b. The lubricating oil 318 sucked into the sub compressor 1b together with the refrigerant gas from the main compressor 5 flows from the sub compressor discharge port 361e through the discharge valve 330 into the sub compression discharge space 370. This lubricating oil 318 is gas-liquid separated in the sub compression discharge space 370 and collected on the upper surface of the sub compressor fixed scroll 361, and then to the oil reservoir space 372 functioning as an oil reservoir through the oil return hole 317. Returned. Further, excess lubricating oil 318 stored in the oil sump space 372 passes through an oil pipe 380 provided at the bottom of the hermetic container 310, and the main compressor due to a differential pressure between the main compressor 5 and the oil sump space 372. 5 and the oil level of the lubricating oil 318 stored in the oil sump space 372 is held at an appropriate position.

[Example when there is no high / low pressure difference]
First, the flow of the refrigerant (the white arrow shown in FIG. 4) will be described. The case where the high and low pressure difference does not occur in the sub-compressor 1b is, for example, a case where the refrigerating system which uses the expander 1a only at the start-up or cooling operation, during heating operation, during operation with a low rotational speed, or the like. In such a case, the suction flow rate of the sub compressor 1b falls below the discharge flow rate of the main compressor 5, the suction pressure of the sub compressor 1b rises above the post-compression pressure, and the bypass check valve 331 is opened. It becomes a state. When the bypass check valve 331 is opened, not all of the sucked refrigerant passes through the sub compression chamber 363, but a part thereof is bypassed.

  That is, the refrigerant sucked from the sub compressor suction pipe 312 passes through the sub compression chamber 363 and is discharged to the sub compression discharge space 370, and from the bypass port 361f via the bypass check valve 331 to the sub compression discharge space. The route to 370 is divided. The bifurcated refrigerant merges in the sub compression discharge space 370 and is then discharged from the sub compressor discharge pipe 314 to the outside of the sealed container 310. When there is no high / low pressure difference in the sub-compressor 1b, the refrigerant flows through such a path.

  Next, the flow of the lubricating oil 318 (black arrows shown in FIG. 4) will be described. Similarly to the refrigerant gas, the lubricating oil 318 that circulates together with the refrigerant gas is discharged into the sub compression discharge space 370 via the sub compression chamber 363 and the sub compression through the bypass check valve 331 from the bypass port 361f. It is divided into a route to the discharge space 370 and flows into the sub-compression discharge space 370. The lubricating oil 318 flowing together with the refrigerant gas is gas-liquid separated in the sub-compression discharge space 370 and accumulates on the upper surface of the sub-compressor fixed scroll 361 and then functions as an oil reservoir through the oil return hole 317. The oil sump space 372 is returned.

[Another example without high / low pressure difference]
The flow of the refrigerant (the white arrow shown in FIG. 5) and the flow of the lubricating oil 318 (the black arrow shown in FIG. 5) will be described together. When there is no high-low pressure difference in the sub-compressor 1b and the sub-compressor 1b is not rotating, the total amount of refrigerant gas and lubricating oil 318 flowing through the refrigeration cycle apparatus flows through the bypass port 361f, and the sub-compression discharge space 370 Will flow into. Thereafter, the refrigerant gas is discharged out of the sealed container 310 through the sub compressor discharge pipe 314. On the other hand, the lubricating oil 318 flowing together with the refrigerant gas is gas-liquid separated in the sub-compression discharge space 370 and collected on the upper surface of the sub-compressor fixed scroll 361, and then as an oil reservoir through the oil return hole 317. It will be returned to the functioning oil sump space 372.

  As described above, in the expander unit 1 according to the first embodiment, when the suction flow rate of the sub compressor 1b is smaller than the discharge flow rate of the main compressor 5, the bypass check valve 331 provided in the expander unit 1 is used. The refrigerant is automatically bypassed for an excessive flow rate, and the lubricating oil 318 circulating with the refrigerant can always pass through the sub-compression discharge space 370 of the sub-compressor 1b. The lubricating oil 318 is gas-liquid separated in the sub-compression discharge space 370 and then returned to the oil reservoir space 372 functioning as an oil reservoir through the oil return hole 317.

Here, the oil supply mechanism in the expander unit 1 will be described.
When the shaft 308 is rotated by the expansion power of the expander 1a, the lubricating oil 318 stored in the oil sump space 372 by the oil supply pump 306 passes through the oil supply hole 308c formed in the shaft 308, and the expansion mechanism side bearing. 351b, sub compression mechanism side bearing 361b, and crank 308b. The lubricating oil 318 leaked to the sub compression discharge space 370 among the lubricating oil 318 supplied to the expansion mechanism side bearing portion 351b, the sub compression mechanism side bearing portion 361b, and the crank portion 308b passes through the oil return hole 317. It is returned to the oil sump space 372.

  With the above configuration, the expander unit 1 has the bypass port 361f and the bypass check valve 331 in the hermetic container 310, so that the expander unit 1 can have a compact structure without increasing its size. Further, the expander unit 1 can automatically bypass the refrigerant corresponding to the excessive flow rate flowing into the sub compressor 1b by the bypass check valve 331. Further, since the expander unit 1 always causes the lubricating oil 318 circulating with the refrigerant to pass through the sub-compression discharge space 370 of the sub-compressor 1b for gas-liquid separation, it can also function as an oil separator. .

Embodiment 2. FIG.
FIG. 6 is a circuit diagram schematically showing a circuit configuration of a refrigeration cycle apparatus 500 according to Embodiment 2 of the present invention. A circuit configuration of the refrigeration cycle apparatus 500 will be described with reference to FIG. The refrigeration cycle apparatus 500 can perform a cooling operation or a heating operation by using a refrigeration cycle that circulates a refrigerant (for example, a supercritical fluid such as carbon dioxide). In FIG. 6, the refrigerant flow during the cooling operation is indicated by a solid line arrow, and the refrigerant flow during the heating operation is indicated by a broken line arrow.

  The refrigeration cycle apparatus 500 according to the second embodiment is characterized by including the expander unit 1 according to the first embodiment. As shown in FIG. 6, the refrigeration cycle apparatus 500 includes an outdoor unit 100 and an indoor unit 200 that are connected by a refrigerant pipe. As the refrigerant used in the refrigeration cycle apparatus 500, for example, carbon dioxide is assumed which becomes a supercritical state at a critical temperature (about 31 ° C.) or higher and heat exchange changes sensible heat. FIG. 6 shows an example in which one outdoor unit 100 and one indoor unit 200 are connected, but the number of units connected is limited to the number shown. is not.

[Outdoor unit 100]
The outdoor unit 100 is installed outside the room and has a function of supplying cold heat to the indoor unit 200. The outdoor unit 100 includes a main compressor 5, a sub compressor 1 b of the expander unit 1, a first four-way valve 2, an outdoor heat exchanger 3, a second four-way valve 4, and a pre-expansion valve 6. The expander 1a of the expander unit 1 is provided so as to be connected in series during the cooling operation. Further, the outdoor unit 100 is provided with a bypass valve 7 that bypasses a part of the refrigerant flowing into the second four-way valve 4 during the cooling operation.

  The main compressor 5 sucks the refrigerant and compresses the refrigerant to a high temperature / high pressure state, and may be constituted by, for example, an inverter compressor capable of capacity control. The first four-way valve 2 and the second four-way valve 4 function as flow path switching means, and switch between the refrigerant flow during the heating operation and the refrigerant flow during the cooling operation. The outdoor heat exchanger 3 is installed between the first four-way valve 2 and the second four-way valve 4 and functions as a radiator or an evaporator depending on the operation mode, and from an outdoor blower such as a fan (not shown). Heat exchange is performed between forcibly supplied air and the refrigerant.

  The pre-expansion valve 6 is provided on the inlet side of the expander 1a and functions as an on-off valve, and matches the passage refrigerant flow rate and power in the expander 1a and the sub compressor 1b. The bypass valve 7 branches the refrigerant pipe connecting the outdoor heat exchanger 3 and the second four-way valve 4, and is in parallel with the pre-expansion valve 6 in a refrigerant pipe that bypasses the second four-way valve 4. Like the pre-expansion valve 6, it functions as an on-off valve. That is, the pre-expansion valve 6 and the first bypass valve 7 make the passage refrigerant flow rate and power in the expander 1a and the sub compressor 1b coincide with each other.

[Indoor unit 200]
The indoor unit 200 is installed in a room or the like having an air conditioning target area, and has a function of supplying cooling air or heating air to the air conditioning target area. The indoor unit 200 is provided with an indoor heat exchanger 9. The indoor heat exchanger 9 functions as a radiator during heating operation, functions as an evaporator during cooling operation, and exchanges heat between air and refrigerant that are forcibly supplied from an indoor fan such as a fan (not shown). The heating air or cooling air to be supplied to the air-conditioning target area is created.

Here, the operation of the refrigeration cycle apparatus 500 during the cooling operation will be described.
FIG. 7 is a ph diagram (diagram illustrating the relationship between the refrigerant pressure (vertical axis) and the enthalpy (horizontal axis)) showing the transition of the refrigerant during the cooling operation. Based on FIG.6 and FIG.7, the operation | movement at the time of the cooling operation of the refrigerating-cycle apparatus 500 is demonstrated based on transition of a refrigerant | coolant state. Note that the refrigerant states at points [A] to [G] shown in FIG. 6 indicate the refrigerant states at [A] to [G] shown in FIG. 7, respectively.

  When the refrigeration cycle apparatus 500 performs a cooling operation, in the outdoor unit 100, the first four-way valve 2 is connected to the sub compressor 1b and the outdoor heat exchanger 3, that is, the first port of the first four-way valve 2. 2a and the second port 2b are communicated, the third port 2c and the fourth port 2d are switched to communicate, and the second four-way valve 4 is connected to the outdoor heat exchanger 3 and the pre-expansion valve 6. In other words, switching is performed so that the first port 4a and the fourth port 4d of the second four-way valve 4 communicate with each other and the second port 4b and the third port 4c communicate with each other. In this state, the operation of the main compressor 5 is started.

  First, the low-temperature and low-pressure gas refrigerant is compressed by the main compressor 5 and discharged as a high-temperature and high-pressure supercritical refrigerant (state [A]). The supercritical refrigerant discharged from the main compressor 5 flows into the sub compressor 1b. The sub compressor 1b is driven by an expander 1a that depressurizes the refrigerant that has flowed through the pre-expansion valve 6. That is, the refrigerant flowing into the sub compressor 1b is compressed by an amount commensurate with the power recovered by the expander 1a. The refrigerant discharged from the sub-compressor 1b flows from the first port 2a of the first four-way valve 2 through the second port 2b (state [C]) into the outdoor heat exchanger 3.

  The refrigerant that has flowed into the outdoor heat exchanger 3 is cooled by releasing heat to the air that is the heating medium supplied from the outdoor blower (not shown) in the outdoor heat exchanger 3 (state [D]). This refrigerant flows out of the outdoor heat exchanger 3 and flows into the pre-expansion valve 6 from the second port 4a of the second four-way valve 4 through the third port 4c. The inlet density of the refrigerant flowing into the pre-expansion valve 6 when the refrigerant flows into the expander 1a is adjusted by the pre-expansion valve 6 (state [E]). The refrigerant that has flowed out of the pre-expansion valve 6 flows into the expander 1a, is depressurized (state [F]), and the expansion power is recovered. The refrigerant flowing out of the expander 1a flows out of the outdoor unit 100 through the first port 4a of the second four-way valve 4 through the fourth port 4d, and flows into the indoor unit 200. At this time, the opening degree of the bypass valve 7 is controlled so that the refrigerant flow rate passing through the sub-compressor 1b and the recovered power are balanced.

  The refrigerant that has flowed into the indoor unit 200 flows into the indoor heat exchanger 9 and exchanges heat with air supplied from an indoor blower (not shown) to process the heat load in the air-conditioning target area (state [B]). . That is, the indoor heat exchanger 9 creates cooling air to be supplied to the air-conditioning target area. This refrigerant flows out of the indoor heat exchanger 9 and the indoor unit 200 and flows into the outdoor unit 100. The refrigerant that has flowed into the outdoor unit 100 flows into the main compressor 5 from the fourth port 2d of the first four-way valve 2 through the third port 2c (state [G]). At this time, the pressure is slightly reduced due to the pressure loss and then sucked into the main compressor 5.

Next, an operation during heating operation of the refrigeration cycle apparatus 500 will be described.
FIG. 8 is a ph diagram (diagram illustrating the relationship between the refrigerant pressure (vertical axis) and the enthalpy (horizontal axis)) showing the transition of the refrigerant during the heating operation. Based on FIG.6 and FIG.8, the operation | movement at the time of the heating operation of the refrigerating-cycle apparatus 500 is demonstrated based on transition of a refrigerant | coolant state. The refrigerant states at points [A] to [G] shown in FIG. 6 are refrigerant states at [A] to [G] shown in FIG.

  FIG. 6 shows an example in which the expander 1a is used during the heating operation as in the cooling operation. However, in the heating operation, unlike the cooling operation, the refrigerant density ratio between the inlet portion of the expander 1a and the inlet portion of the sub compressor 1b in the expander unit 1 is increased. The recovery loss of the expansion power for balancing is increased. Therefore, the second four-way valve 4 may be abolished as necessary, and the expander unit 1 may not be used during the heating operation.

  When the refrigeration cycle apparatus 500 performs the heating operation, in the outdoor unit 100, the first four-way valve 2 is connected to the sub compressor 1b and the indoor heat exchanger 9, that is, the first port of the first four-way valve 2. 2a and the fourth port 2d are communicated, the second port 2b and the third port 2c are switched to communicate, and the second four-way valve 4 is connected to the indoor heat exchanger 9 and the pre-expansion valve 6. That is, the first port 4a and the second port 4b of the second four-way valve 4 are communicated, and the third port 4c and the fourth port 4d are switched to communicate. In this state, the operation of the main compressor 5 is started. In the refrigeration cycle apparatus 500 during heating operation, the basic decompression function is realized by the expander 1a of the expander unit 1, and when the amount of decompression is insufficient, the outlet temperature of the indoor heat exchanger 9 is set to the indoor load. The amount of pressure reduction is adjusted by the pre-expansion valve 6 so that the temperature becomes appropriate.

  First, the low-temperature and low-pressure gas refrigerant is compressed by the main compressor 5 and discharged as a high-temperature and high-pressure supercritical refrigerant (state [A]). The supercritical refrigerant discharged from the main compressor 5 flows into the sub compressor 1b. This refrigerant is further compressed by the sub compressor 1b. The refrigerant flowing out from the sub compressor 1b flows into the indoor unit 200 from the first port 2a of the first four-way valve 2 via the fourth port 2d (state [B]). The refrigerant that has flowed into the indoor unit 200 flows into the indoor heat exchanger 9. The refrigerant that has flowed into the indoor heat exchanger 9 dissipates heat to indoor air supplied from an indoor fan (not shown) in the indoor heat exchanger 9 and is cooled (state [F]). That is, the indoor heat exchanger 9 creates heating air to be supplied to the air conditioning target area. The medium-temperature and high-pressure refrigerant that has flowed out of the indoor heat exchanger 9 then flows into the outdoor unit 100.

  The refrigerant flowing into the outdoor unit 100 flows into the pre-expansion valve 6 from the fourth port 4d of the second four-way valve 4 via the third port 4c. This refrigerant is slightly decompressed by the pre-expansion valve 6 (state [E]). The refrigerant flowing out from the pre-expansion valve 6 (state [E]) flows into the expander 1a, and the expansion power is recovered. The refrigerant that has flowed out of the expander 1a flows into the outdoor heat exchanger 3 from the first port 4a of the second four-way valve 4 via the second port 4b (state [D]). The refrigerant flowing into the outdoor heat exchanger 3 is evaporated and gasified (state [C]) by exchanging heat with air supplied from an outdoor fan (not shown). Thereafter, the gas refrigerant flowing out of the outdoor heat exchanger 3 is again sucked into the main compressor 5 from the second port 2b of the first four-way valve 2 via the third port 2c (state [G ]). At this time, the pressure is slightly reduced due to the pressure loss and then sucked into the main compressor 5.

  As described above, in the refrigeration cycle apparatus 500 according to the second embodiment, the main compressor 5 takes part of the compression process of the refrigeration cycle, and the sub compressor 1b of the expander unit 1 performs the remaining compression process. It is supposed to take part. Further, the compression power of the sub compressor 1b is covered by the recovery power of the expander 1a. Therefore, by providing the expander unit 1, the refrigeration cycle apparatus 500 can be made compact, a wide range of operating conditions can be achieved, and the reliability can be high and the efficiency can be increased. Further, the expander unit 1 can automatically bypass the refrigerant corresponding to the excessive flow rate flowing into the sub compressor 1b by the bypass check valve 331. Further, since the expander unit 1 always causes the lubricating oil 318 circulating with the refrigerant to pass through the sub-compression discharge space 370 of the sub-compressor 1b for gas-liquid separation, it can also function as an oil separator. .

  Further, since the lubricating oil 318 separated in the expander unit 1 can be directly transported between the main compressor 5 and the expander unit 1 without passing through the circuit of the refrigeration cycle, the expansion oil 318 is expanded. The machine unit 1 functions as an oil separator of the main compressor 5 and has an effect of suppressing a decrease in heat exchange performance due to the mixture of the lubricating oil 318 in the refrigerant. Further, even when the lubricating oil 318 in the main compressor 5 is taken out to the outside during a transient operation such as startup, the lubricating oil 318 is quickly returned from the expander unit 1. It is possible to effectively realize prevention of seizure due to lack of the lubricating oil 318 on the moving part or the like.

FIG. 9 is a schematic diagram for explaining the relationship between the refrigerant flow rate and the rotation speed of the expansion / compression mechanism. Based on FIG. 9, the relationship between the refrigerant flow rate and the rotation speed of a general expansion / compression mechanism will be described. As shown in FIG. 9, when there is a sub compressor 1b driven by the expander 1a, the weight flow rate of refrigerant passing through the expander 1a is Ge, the flow rate of the sub compressor 1b is Gc, and the suction of the expander 1a If the stroke volume is Vei, the suction stroke volume of the sub-compressor 1b is Vcs, the refrigerant specific volume at the inlet of the expander 1a is νei, and the refrigerant specific volume at the inlet of the sub-compressor 1b is νcs, it is determined on the expander 1a side. The rotational speed _NE is expressed as shown in Equation (1).

また、サブ圧縮機１ｂ側の回転数Ｎ_C は、式（２）のように表される。

したがって、膨張機１ａとサブ圧縮機１ｂとの回転数をマッチングさせる条件であるＮ_E ＝Ｎ_C から、式（３）を満たさなければならないことになる。

Further, the rotational speed N _C on the sub-compressor 1b side is expressed as in Expression (2).

Therefore, Equation (3) must be satisfied from N _E = N _C which is a condition for matching the rotational speeds of the expander 1a and the sub compressor 1b.

  The stroke volume ratio σvec of the expander 1a and the sub-compressor 1b shown in Expression (3) is a constant that determines the dimensions of the device with respect to a certain design condition. When operating under conditions other than the design conditions, it is necessary to adjust the volume flow rate ratio (Geνei / Gcνcs) so as to satisfy Equation (3). When the sub-compressor 1b handles all of the compression process of the refrigeration cycle (in this case, the sub-compressor 1b needs to use not only the recovered power from the expander 1a but also another drive source), the expander Since the specific volumes νei and νcs at the inlets of 1a and the sub-compressor 1b are determined from the operating conditions, the weight flow rate Ge is usually adjusted by means such as a bypass such as the bypass valve 7. At this time, the flow rate to be bypassed is a non-recovery flow rate at which the expansion power cannot be recovered, and the power recovery effect is reduced. Therefore, it is necessary to suppress the bypass flow rate as much as possible.

  As shown in FIG. 7, a part of the compression process (point G → point A) of the refrigeration cycle apparatus 500 is carried by the motor driven main compressor 5, and the remaining part of the compression process (point A → point C) is performed. When the recovery power drive sub-compressor 1b bears, the specific volume νcs at the inlet of the sub-compressor 1b changes depending on the pressure at the point A. For this reason, even if the specific volume at point D and point G is determined from the operating conditions, it is possible to adjust the specific volume νcs at the inlet of the sub compressor 1b for the rotational speed matching. However, since the sub-compressor 1b is driven only by the expander 1a, it is necessary to perform power matching that covers the compressed power with the recovered power.

  The pressure at the point A shown in FIG. 7 has a lower limit, and the adjustment of the specific volume νcs at the inlet of the sub compressor 1b by the pressure at the point A also has a limit. Therefore, the power on the expander 1a side and the power on the sub-compressor 1b side must be balanced, and the rotational speed matching condition of Expression (3) must be satisfied. Then, on the expander 1a side, the passage flow rate Ge of the expander 1a is adjusted by adjusting the opening of the bypass valve 7 and the like provided in parallel with the expander 1a to bypass the refrigerant. .

  As described above, a part of the compression process of the refrigeration cycle apparatus 500 is performed by the motor-driven main compressor 5 as compared with the case where the sub compressor 1b of the expander unit 1 performs the entire compression process of the refrigeration cycle apparatus 500. In the case where the remaining part of the compression process is carried by the sub-compressor 1b of the scroll-type expander unit 1 driven by the recovery power, the rotation speed is adjusted by the specific volume νcs at the inlet of the sub-compressor 1b and the sub-compressor Since the adjustment of the compression power by the pressure increase width in 1b is used in combination, it is possible to suppress a reduction in the recovery effect due to the bypass.

  In the second embodiment, a bypass check valve 331 is built in the sub compressor 1b. When the expander 1a is driven and a high / low pressure difference is generated in the sub compressor 1b, the bypass reverse valve The stop valve 331 is closed. On the other hand, the sub-compressor 1b is determined based on the discharge flow rate from the other main compressors 5 when the sub-compressor 1b does not produce a high-low pressure difference or during the heating operation of the refrigeration cycle apparatus 500 that uses the expander unit 1 only in the cooling operation. During the operation when the intake flow rate is lower, the bypass check valve 331 is opened, so that an excessive flow amount of the refrigerant flowing into the sub compressor 1b is automatically bypassed.

Embodiment 3 FIG.
FIG. 10 is a longitudinal sectional view showing the configuration of the expander unit 11 according to Embodiment 3 of the present invention. Based on FIG. 10, the structure of the expander unit 11 is demonstrated. Like the expander unit 1 according to the first embodiment, the expander unit 11 is an integrated scroll-type expander and compressor, and collects and collects the expansion power generated when the refrigerant expands. It has a function of compressing a refrigerant using expansion power. It should be noted that the difference from the expander unit 1 according to Embodiment 1 will be mainly described.

  The expander unit 11 includes an expander 1a and a sub compressor 1b '. The sub-compressor 1b ′ has basically the same configuration as the sub-compressor 1b of the expander unit 1 according to Embodiment 1, but forms a communication path 390 inside the sub-compressor fixed scroll 361. The discharge chamber 361g and the bypass check valve chamber 361h are communicated with each other through a communication path 390. That is, the expander unit 11 enters the sub compression discharge space 370 from the bypass port 361f to the sub compression discharge space 370 via the bypass check valve 331 and the sub compressor discharge port 361e via the discharge valve 330. It differs from the expander unit 1 according to the first embodiment in that the two discharge paths and the other discharge paths are joined in the middle (communication path 390), and the outlet communicating with the sub compression discharge space 370 is provided at one place. It is.

  FIG. 11 is a plan view showing a configuration of the sub compressor 1b '. FIG. 11 shows a cross-sectional view of the expander unit 11 taken along line AA shown in FIG. However, in FIG. 11, the axis 308 is omitted. Based on FIG. 11, a state where the spiral 361s and the spiral 362s of the sub compressor 1b 'are combined will be described in detail. As shown in a region surrounded by a thick broken line shown in FIG. 11, the sub compressor 1b ′ includes a discharge passage 361g, a bypass check valve chamber 361h, and a communication passage 390 formed inside the sub compressor fixed scroll 361. Are configured to communicate with each other.

  By adopting such a structure, in addition to obtaining the same bypass effect as that of the sub compressor 1b of the expander unit 1 according to Embodiment 1, the bypass path and the discharge path to the sub compression discharge space 370 can be obtained. Since the openings are gathered in one place, it is possible to arrange the openings apart from the sub compressor discharge pipe 314. Therefore, the sub compression discharge space 370 can be effectively used as the oil separation space, and the oil separation efficiency by the expander unit 11 can be effectively improved. The expander unit 11 according to the third embodiment can be provided in the refrigeration cycle apparatus 500 according to the second embodiment, similarly to the expander unit 1 according to the first embodiment.

Embodiment 4 FIG.
FIG. 12 is a longitudinal sectional view showing the configuration of the expander unit 21 according to Embodiment 4 of the present invention. Based on FIG. 12, the structure of the expander unit 21 is demonstrated. As with the expander unit 1 according to the first embodiment, the expander unit 21 is an integrated scroll-type expander and compressor, and collects and collects the expansion power generated when the refrigerant expands. It has a function of compressing a refrigerant using expansion power. The description will focus on the differences between the expander unit 1 according to the first embodiment and the expander unit 11 according to the third embodiment.

  The expander unit 21 includes an expander 1a and a sub compressor 1b ''. The sub-compressor 1b '' has basically the same configuration as the sub-compressor 1b of the expander unit 1 according to Embodiment 1, but the bypass port 361f (the bypass port 361fa and the bypass port 361fb) Instead of communicating with the suction chamber 374, it communicates with the sub-compression chamber 363. Further, like the expander unit 11 according to the third embodiment, the bypass path from the bypass port 361f to the sub compression discharge space 370 via the bypass check valve 331, and the discharge valve 330 from the sub compressor discharge port 361e. The two paths of the discharge path reaching the sub-compression discharge space 370 through the middle are joined in the middle (communication path 390), and one outlet is connected to the sub-compression discharge space 370.

  FIG. 13 is a plan view showing the configuration of the sub compressor 1b ″. FIG. 13 is a cross-sectional view of the expander unit 21 taken along line AA shown in FIG. However, in FIG. 13, it is assumed that the shaft 308 is omitted. Based on FIG. 13, a state where the spiral 361 s and the spiral 362 s of the sub-compressor 1 b ″ are combined will be described in detail. In the sub-compression chamber 363, two outermost compression chambers and one innermost compression chamber are formed by rotating the sub-compressor swing scroll 362 as the shaft 308 rotates. The volume is gradually reduced to perform continuous compression.

  In this sub compressor 1b ″, two bypass ports (bypass port 361fa and bypass port 361fb) are provided at the tips of the spiral 362s of the sub compressor swing scroll 362 and the spiral 361s of the sub compressor fixed scroll 361, respectively. The position of the cross-sectional shape of the flow path that does not interfere with the tip seal 364, which is advanced inward by 360 degrees from the inward surface side spiral start point and the outward surface side spiral start point of the sub-compressor fixed scroll 361 that contributes to compression Are formed so as to penetrate the base plate 361a.

  With such a structure, the bypass port 361fa and the bypass port 361fb always open to the outermost peripheral compression chamber immediately after the start of the compression stroke, so that the refrigerant gas can be bypassed without generating unnecessary compression power. A bypass effect is obtained. Further, since the bypass refrigerant gas passes through the sub compression chamber 363, the gap seal and the spiral sliding portion can be lubricated by the lubricating oil 318 that circulates together with the refrigerant gas, and the power loss during the startup bypass operation is reduced. The start-up response can be effectively improved.

  In the fourth embodiment, the bypass port 361fa and the bypass port 361fb are arranged at 360 ° inward from the end of the spiral 361s of the fixed compressor scroll 361 that contributes to compression, one at each of the two outermost compression chambers. Although provided at the advanced position, the number of bypass ports 361f formed is not particularly limited, and a plurality of bypass ports 361f may be provided at further positions. By doing so, the bypass function of the sub-compressor 1b '' can be further improved. Further, the expander unit 21 according to the fourth embodiment can be provided in the refrigeration cycle apparatus 500 according to the second embodiment, similarly to the expander unit 1 according to the first embodiment.

  In the first embodiment, the third embodiment, and the fourth embodiment, as shown in FIG. 12, a shielding plate 381 for promoting the oil separation effect may be provided in the sub-compression discharge space 370. If such a shielding plate 381 is provided in the sub-compression discharge space 370, the oil separation efficiency by the expander unit can be further improved. Moreover, although the case where the carbon dioxide was used for the refrigerant | coolant was demonstrated to the example, the kind of refrigerant | coolant is not limited to a carbon dioxide. Other refrigerants may be used as long as they are in a critical state. As a refrigerant in a supercritical state, for example, there is a mixed refrigerant composed of carbon dioxide and ether (for example, dimethyl ether, hydrofluoroether, etc.).

It is a longitudinal cross-sectional view which shows the structure of the expander unit which concerns on Embodiment 1. FIG. It is a top view which shows the structure of a sub compressor. It is a longitudinal cross-sectional view for demonstrating the flow of the refrigerant gas and lubricating oil in a subcompressor in case there exists a high and low pressure difference. It is a longitudinal cross-sectional view for demonstrating an example of the flow of the refrigerant gas and lubricating oil in a sub compressor in the case of no high and low pressure difference. It is a longitudinal cross-sectional view for demonstrating another example of the flow of the refrigerant gas and lubricating oil in a sub compressor in the case of no high-low pressure difference. 6 is a circuit diagram schematically showing a circuit configuration of a refrigeration cycle apparatus according to Embodiment 2. FIG. It is a ph diagram which shows change of a refrigerant at the time of air conditioning operation. It is a ph diagram which shows the change of the refrigerant at the time of heating operation. It is a schematic diagram for demonstrating the relationship between the refrigerant | coolant flow volume and rotation speed of an expansion / compression mechanism. It is a longitudinal cross-sectional view which shows the structure of the expander unit which concerns on Embodiment 3. FIG. It is a top view which shows the structure of a sub compressor. It is a longitudinal cross-sectional view which shows the structure of the expander unit which concerns on Embodiment 4. FIG. It is a top view which shows the structure of a sub compressor.

Explanation of symbols

  1 expander unit, 1a expander, 1b sub compressor, 1b ′ sub compressor, 1b ″ sub compressor, 2 first four-way valve, 2a first port, 2b second port, 2c third port, 2d second 4 ports, 3 outdoor heat exchangers, 4 second four-way valve, 4a first port, 4b second port, 4c third port, 4d fourth port, 5 main compressor, 6 pre-expansion valve, 7 bypass valve, 9 Indoor heat exchanger, 11 expander unit, 21 expander unit, 100 outdoor unit, 200 indoor unit, 306 oil pump, 307 Oldham ring, 308 shaft, 308b crank part, 308c oil hole, 309a balance weight, 309b balance weight, 310 airtight container, 312 sub compressor suction pipe, 313 expander suction pipe, 314 sub compressor discharge pipe, 315 expander discharge pipe, 317 oil return hole, 3 8 Lubricating oil, 330 Discharge valve, 331 Bypass check valve, 351 Expander fixed scroll, 351a Base plate, 351b Expansion mechanism side bearing, 351d Expander suction port, 351s Spiral, 352 Swing scroll for expander, 352a Base plate, 352s spiral, 353 expansion chamber, 354 tip seal, 361 Sub compressor fixed scroll, 361a Base plate, 361b Sub compression mechanism side bearing, 361d Sub compressor suction port, 361e Sub compressor discharge port, 361f Bypass Port, 361fa Bypass port, 361fb Bypass port, 361g Discharge chamber, 361h Bypass check valve chamber, 361s spiral, 362 Sub-compressor orbiting scroll, 362a Base plate, 362s spiral, 363 Sub compression chamber, 364 Tip seal, 36 Peripheral seal, 370 sub-compression discharge space, 371 orbiting scroll movement space 372 sump space 374 suction chamber, 380 oil pipe, 381 shielding plate, 390 communication channel, 500 refrigeration cycle apparatus.

Claims (9)

An expander that recovers expansion power when the refrigerant is decompressed, a sub compressor that compresses the refrigerant using the expansion power in a sealed container, and a sub compressor suction pipe that sucks the refrigerant supplied to the sub compressor; An expander unit in which a sub-compressor discharge pipe for discharging refrigerant compressed by the sub-compressor is communicated with the inside of the sealed container;
A sub-compression chamber formed in the sub-compressor for compressing the refrigerant;
A suction chamber formed in the sub compressor and extending from the sub compressor suction pipe to the sub compression chamber;
A sub compressor discharge port communicating with the sub compression chamber and discharging refrigerant compressed in the sub compression chamber;
A discharge chamber formed in the sub-compressor and from which refrigerant is discharged from the sub-compressor discharge port;
A sub-compression discharge space provided in the sealed container, through which the refrigerant from the discharge chamber passes;
An oil sump space formed in the sealed container for storing lubricating oil;
An oil return hole penetrating the sub compressor and the expander and communicating the sub compression discharge space and the oil sump space;
A bypass port, provided in the sealed container, for communicating at least one of the suction chamber or the sub compression chamber and the sub compression discharge space;
An expander unit, comprising: a bypass on-off valve provided in the sealed container for opening and closing the bypass port. The path from the bypass port to the sub-compression discharge space and the path from the discharge chamber to the sub-compression discharge space are independently communicated with the sub-compression discharge space. 2. The expander unit according to 1. The path from the bypass port to the sub-compression discharge space and the path from the discharge chamber to the sub-compression discharge space merge to communicate with the sub-compression discharge space. The expander unit described in 1. The expander unit according to any one of claims 1 to 3, wherein the bypass on-off valve is configured by a check valve. Both of the expander and the sub-compressor are of a scroll type. The expander unit according to any one of claims 1 to 4, wherein the expander unit is a scroll type. The sub-compressor
It has a swing scroll for the sub compressor and a fixed scroll for the sub compressor,
The expander is
It has a swing scroll for the expander and a fixed scroll for the expander,
6. The expander unit according to claim 5, wherein the sub-compressor swing scroll and the expander swing scroll are configured integrally with a back-to-back structure or a base plate. . A shaft for rotationally driving the sub-compressor orbiting scroll and the expander orbiting scroll passes through the central portion thereof in the vertical direction.
An oil supply hole is formed inside the shaft,
The expander unit according to claim 5 or 6, wherein an oil supply pump for pumping up the lubricating oil stored in the oil sump space is attached to a lower end of the shaft. The expander unit according to any one of claims 1 to 7, a main compressor, an outdoor heat exchanger, and an indoor heat exchanger,
The main compressor, the sub compressor constituting the expander unit, the outdoor heat exchanger, the expander constituting the expander unit, and the indoor heat exchanger are connected in series during the cooling operation. A refrigeration cycle apparatus characterized by being connected as described above. The refrigeration cycle apparatus according to claim 8, wherein a refrigerant that is in a supercritical state on the high-pressure side is used.

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