WO2012104934A1

WO2012104934A1 - Scroll expander, and refrigeration cycle with the scroll expander

Info

Publication number: WO2012104934A1
Application number: PCT/JP2011/003628
Authority: WO
Inventors: 下地　美保子; 角田　昌之; 英彰永田; 石園　文彦; 関屋　慎; 利秀幸田; 加賀　邦彦
Original assignee: 三菱電機株式会社
Priority date: 2011-02-04
Filing date: 2011-06-24
Publication date: 2012-08-09
Also published as: JP2014077353A

Abstract

A scroll expander (1) has a liquid injection port (93) provided at a stationary scroll (61) which is a second stationary scroll, the liquid injection port (93) being capable of injecting a liquid refrigerant, which is supplied from the outside of a hermetically closed container (10), into a sub-compression chamber (6a).

Description

Scroll expander and refrigeration cycle apparatus provided with the scroll expander

The present invention relates to a scroll expander that expands a refrigerant and recovers power, and a refrigeration cycle apparatus including the scroll expander, and in particular, an expansion mechanism on one side with two orbiting scrolls back to back. The present invention relates to a scroll expander having a compression mechanism on the other side and a refrigeration cycle apparatus including the scroll expander.

Conventionally, there has been disclosed a scroll expander that recovers power generated during expansion of a refrigerant and uses the power to compress the refrigerant. As such, the compression chamber is formed by combining the orbiting scroll having the first and second spiral teeth on both sides of the base plate, and the first and second scroll teeth of the orbiting scroll and the first fixed scroll. An expansion chamber is formed by combining a compression mechanism having a suction port in the outer peripheral portion and a discharge port in the central portion and the second spiral teeth of the orbiting scroll and the spiral teeth of the second fixed scroll. And an expansion mechanism provided with a discharge port on the outer peripheral portion thereof, and a device for reducing the thrust force acting on the orbiting scroll has been proposed (for example, see Patent Document 1).

Also, in an expander in which the compression mechanism and expansion mechanism are directly connected to the motor, liquid refrigerant branched at the outlet of the condenser is injected into the intermediate pressure part of the compression mechanism to improve heating capacity and discharge gas superheat There has been proposed one that can be adjusted (see, for example, Patent Document 2).

Further, in an expander (compression expansion unit) in which the compression mechanism and the expansion mechanism are directly connected to the motor in one axis, the refrigerant gas separated by the gas-liquid separator provided on the downstream side of the expansion mechanism is compressed in the compression mechanism. There has been proposed a circuit in which a circuit for injecting is provided, and the entire amount of refrigerant is allowed to flow through the expansion mechanism so that the flow rate balance between the expansion mechanism side and the compression mechanism side is achieved without wastefully bypassing expansion power (for example, And Patent Document 3).

Japanese Unexamined Patent Publication No. 03-59355 (pages 4 to 5, FIGS. 1 and 2) JP 2009-52752 (pages 3 to 4, FIGS. 1 and 3) JP 2006-284086 (pages 5 to 11 and FIG. 1)

In a scroll expander in which two swinging scrolls are back-to-back as described in Patent Document 1 and an expansion mechanism is provided on one side and a compression mechanism is provided on the other side, and the expansion mechanism and the compression mechanism are integrated. When the orbiting scroll is revolved by the driving means, the low-temperature and low-pressure fluid flowing in from the suction port on the outer peripheral portion is compressed to high temperature and high pressure on the compression mechanism side and discharged from the discharge port in the center. On the other hand, on the expansion mechanism side, the low-temperature and high-pressure fluid cooled by the heat exchanger through the compressor and flowing in from the suction port in the central part is expanded to low temperature and low pressure and discharged from the discharge port in the outer peripheral part. In such a scroll expander, when the central portion of the compression mechanism is hot and the central portion of the expansion mechanism is cold, a heat leak occurs from the compression mechanism side to the expansion mechanism side via the base plate of the orbiting scroll. There was a problem that the ability would decrease.

Further, in an expander in which the compression mechanism and the expansion mechanism are directly connected to the motor as described in Patent Document 2 and Patent Document 3, heat leakage from the compression mechanism side to the expansion mechanism side is small. However, there is a problem that the thrust force acting on the orbiting scroll cannot be reduced, and the reliability of the supporting portion of the orbiting scroll is lowered.

The present invention has been made to solve the above-described problems, and suppresses heat leakage from the compression mechanism side to the expansion mechanism side while reducing the thrust force, and highly efficient scroll expansion under a wide range of operating conditions. It aims at obtaining the refrigerating-cycle apparatus provided with the machine and this scroll expander.

The scroll expander according to the present invention forms an expansion chamber by a first swing scroll and a first fixed scroll, expands a refrigerant sucked into the expansion chamber and recovers power, and the first swing scroll. A sub-compression chamber is formed by the second orbiting scroll and the second fixed scroll that are integrated with the moving scroll, and the refrigerant sucked into the sub-compression chamber is compressed using the power recovered by the expansion mechanism. A scroll expander having a sub-compression mechanism, the expansion mechanism, and a sealed container that accommodates the sub-compression mechanism, and a liquid injection port capable of injecting liquid refrigerant from outside the sealed container into the sub-compression chamber. It is provided in the second fixed scroll.

A refrigeration cycle apparatus according to the present invention includes the scroll expander, a main compressor, a gas cooler, a throttle device, and an evaporator, and the sub-compression mechanism is disposed on the discharge side of the main compressor. The expansion mechanism is connected between the gas cooler and the evaporator so that the expansion devices are arranged in parallel.
Further, a refrigeration cycle apparatus according to the present invention includes the scroll expander, a main compressor, a gas cooler, a throttling device, and an evaporator, and the sub-compression mechanism is connected to the main compressor. The expansion mechanism is connected to the suction side, and the expansion mechanism is connected to the downstream side of the expansion device.

According to the scroll expander of the present invention, since the liquid injection pipe communicating with the condenser outlet is connected to the liquid injection port communicating with the sub compression chamber, it is possible to reduce the thrust load acting on the orbiting scroll. The compressed gas is cooled by the liquid injection into the sub compression chamber, and heat leakage from the sub compression mechanism side to the expansion mechanism side via the base plate of the orbiting scroll can be suppressed.

According to the refrigeration cycle apparatus according to the present invention, since the scroll expander is provided, an operation with high cycle efficiency can be realized.

It is a schematic longitudinal cross-sectional view which shows the structure of the scroll expander which concerns on Embodiment 1 of this invention. They are the top view (a) and sectional drawing (b) of the fixed scroll of the sub compression mechanism shown in FIG. It is the top view (a) and sectional drawing (b) of the rear flange of the expansion mechanism shown in FIG. It is a circuit diagram which shows typically the basic composition of the refrigerating-cycle apparatus using the scroll expander which concerns on Embodiment 1 of this invention. It is a schematic sectional drawing which shows typically the expansion mechanism and subcompression mechanism of the scroll expander which concern on Embodiment 1 of this invention. It is a Mollier diagram which shows the state quantity change of the refrigerant | coolant in the refrigerating-cycle apparatus using the scroll expander which concerns on Embodiment 1 of this invention. It is a Mollier diagram which shows the state quantity change of the refrigerant | coolant in the refrigerating-cycle apparatus when the heat leak from a sub compression mechanism to an expansion mechanism is large. It is the top view (a) and sectional drawing (b) of the fixed scroll of the sub compression mechanism of the scroll expander concerning Embodiment 2 of the present invention. It is a circuit diagram which shows typically the basic composition of the refrigerating-cycle apparatus which concerns on Embodiment 3 of this invention. It is a circuit diagram which shows typically the basic composition of the refrigerating-cycle apparatus which concerns on Embodiment 4 of this invention. It is a schematic longitudinal cross-sectional view which shows the structure of the scroll expander which concerns on another embodiment of this invention.

Hereinafter, embodiments of the scroll expander according to the present invention will be described with reference to the drawings.

Embodiment 1 FIG.
FIG. 1 is a schematic longitudinal sectional view showing a configuration of a scroll expander 1 according to Embodiment 1 of the present invention. 2 is a top view (a) and a cross-sectional view (b) of the fixed scroll 61 of the sub-compression mechanism 6 shown in FIG. 3 is a top view (a) and a sectional view (b) of the rear flange 90 shown in FIG. Based on FIG. 1, the structure and effect | action of the scroll expander 1 are demonstrated. 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. Further, the cross-sectional view of FIG. 2B represents the AA cross-section of FIG.

A scroll expander 1 according to Embodiment 1 of the present invention includes a scroll-type expansion mechanism and a compression mechanism in a sealed container 10, expands a refrigerant by the expansion mechanism, recovers power generated at that time, The refrigerant has a function of compressing the refrigerant by the compression mechanism using the expansion power. As shown in FIG. 1, the scroll expander 1 includes an expansion mechanism 5 and a sub compression mechanism 6. The expansion mechanism 5 and the sub compression mechanism 6 are accommodated in a sealed container 10 that is a pressure container. As shown in FIG. 1, the expansion mechanism 5 is installed below the sealed container 10, and the sub-compression mechanism 6 is installed above the sealed container 10, that is, above the expansion mechanism 5.

The expansion mechanism 5 includes a fixed scroll 51 (first fixed scroll) having spiral teeth 51c formed on a base plate 51a, and an orbiting scroll 52 (first swing scroll) having spiral teeth 52c formed on a base plate 52a. ). As shown in FIG. 1, the fixed scroll 51 is disposed on the lower side, and the swing scroll 52 is disposed on the upper side. The spiral teeth 51c of the fixed scroll 51 are erected as spiral protrusions on one surface of the base plate 51a. The spiral teeth 52c of the swing scroll 52 are erected as spiral protrusions on one surface of the base plate 52a.

The spiral teeth 51c of the fixed scroll 51 and the spiral teeth 52c of the swing scroll 52 are arranged so as to mesh with each other. By disposing the spiral teeth 51c of the fixed scroll 51 and the spiral teeth 52c of the orbiting scroll 52 so as to mesh with each other, an expansion chamber 5a whose volume changes relatively is formed. Note that a through hole through which a shaft 8 (described later) passes is formed in substantially the center of the fixed scroll 51 and the swing scroll 52.

The sub-compression mechanism 6 includes a fixed scroll 61 (second fixed scroll) having spiral teeth 61c formed on a base plate 61a, and an orbiting scroll 62 (second swinging) having spiral teeth 62c formed on a base plate 62a. Scroll). As shown in FIG. 1, the fixed scroll 61 is disposed on the upper side, the orbiting scroll 62 is disposed on the lower side, and the upper side of the orbiting scroll 52. The spiral teeth 61c of the fixed scroll 61 are erected as spiral protrusions on one surface of the base plate 61a. Further, the spiral teeth 62c of the swing scroll 62 are erected as spiral protrusions on one surface of the base plate 62a.

The spiral teeth 61c of the fixed scroll 61 and the spiral teeth 62c of the swing scroll 62 are arranged so as to be engaged with each other. By arranging the spiral teeth 61c of the fixed scroll 61 and the spiral teeth 62c of the orbiting scroll 62 to mesh with each other, a sub-compression chamber 6a whose volume changes relatively is formed. Note that a through hole through which a shaft 8 to be described later passes is formed at substantially the center of the fixed scroll 61 and the swing scroll 62.

The base plate 61a of the fixed scroll 61 has a bearing portion 61b in which the periphery of a through hole through which a shaft 8 described later passes, that is, a substantially central portion protrudes to the back surface (upper side surface of the paper surface) (FIG. 2B). reference). And the bearing part 61b is included and fitted in the through-hole 96 provided in the approximate center part of the rear flange 90 (refer FIG. 3). That is, the fixed scroll 61 is configured such that the base plate 61 a and the rear flange 90 are combined so that the bearing portion 61 b is included and fitted in the through hole 96. Further, a cooling groove (cooling space) 91 having, for example, a flat ring shape is provided on the upper surface of the base plate 61a of the fixed scroll 61 on the outer peripheral surface side of the bearing portion 61b. The cooling groove 91 is formed as a notch groove.

Here, the orbiting scroll 52 of the expansion mechanism 5 and the orbiting scroll 62 of the sub-compression mechanism 6 are configured integrally by sharing a back-to-back structure or a base plate.

Through holes are formed in the central portions of the fixed scroll 51 and the swing scroll 52 of the expansion mechanism 5 and the fixed scroll 61 and the swing scroll 62 of the sub-compression mechanism 6, and the shaft 8 passes through these through holes. It is provided as follows. The shaft 8 is rotatably supported at both ends by a bearing portion 51 b and a bearing portion 61 b formed at the center of each of the fixed scroll 51 of the expansion mechanism 5 and the fixed scroll 61 of the sub-compression mechanism 6. In addition, a crank portion 8b (oscillating shaft) for eccentrically driving the orbiting scroll 52 and the orbiting scroll 62 is provided at the center of the orbiting scroll 52 and the orbiting scroll 62. The rocking scroll 52 and the rocking scroll 62 can swing.

The expansion mechanism 5 is connected to an expansion suction pipe 13 that sucks the refrigerant and an expansion discharge pipe 15 that discharges the expanded refrigerant. The expansion suction pipe 13 is installed on the side surface of the sealed container 10, for example, on the outer peripheral side of the expansion mechanism 5, and the central side of the expansion mechanism 5 via the expansion suction port 51 d provided on the base plate 51 a of the fixed scroll 51. Is communicated with the expansion chamber 5a. The expansion / suction port 51d is formed so as to penetrate the inside of the base plate 51a of the fixed scroll 51.

The expansion / discharge pipe 15 is installed on the side surface of the hermetic container 10, for example, on the outer peripheral side of the sub-compression mechanism 6, and the expansion / contraction mechanism 5 is swung via an expansion / discharge port 51 e provided on the base plate 61 a of the fixed scroll 61. The moving scroll 52 and the orbiting scroll motion space 71 which is a pressure space formed on the outer peripheral side of the orbiting scroll 62 of the sub compression mechanism 6 are communicated. The expansion / discharge port 51e is formed so as to penetrate the inside of the base plate 61a of the fixed scroll 61.

Therefore, the refrigerant sucked into the expandable material 5a on the center side of the expansion mechanism 5 through the expansion suction pipe 13 and the expansion suction port 51d and expanded and depressurized by the expansion mechanism 5 is an expansion chamber located at the outermost peripheral portion of the expansion mechanism 5. 5a is discharged into the orbiting scroll motion space 71 and further discharged from the expansion / discharge pipe 15 through the expansion / discharge port 51e. The orbiting scroll movement space 71 is provided, for example, on the outer peripheral portion of the base plate 61a of the fixed scroll 61 of the sub-compression mechanism 6 and the annular convex portion 51f provided on the outer peripheral portion of the base plate 51a of the fixed scroll 51 of the expansion mechanism 5. And the inner wall of the annular convex portion 51f and the annular convex portion 61f, the base plate 52a of the swing scroll 52 of the expansion mechanism 5, and the swing scroll 62 of the sub compression mechanism 6. It may be formed by surrounding with the base plate 62a.

The sub-compression mechanism 6 is connected to a sub-compression suction pipe 12 that sucks the refrigerant and a sub-compression discharge pipe 14 that discharges the compressed refrigerant. The sub-compression suction pipe 12 is installed, for example, on the side surface of the hermetic container 10, and the outer periphery of the sub-compression mechanism 6 via a sub-compression suction port 61 d provided on the base plate 61 a of the fixed scroll 61 of the sub-compression mechanism 6. It communicates with the sub compression chamber 6a in the section. The sub-compression suction port 61d is formed so as to penetrate the base plate 61a of the fixed scroll 61.

The sub-compression discharge pipe 14 is installed on the upper side surface of the sealed container 10, for example. The sub compression discharge pipe 14 communicates with an upper space 70 in the sealed container 10 formed above the fixed scroll 61 of the sub compression mechanism 6. Further, a sub-compression discharge port 61 e for discharging the compressed refrigerant to the upper space 70 is formed on the base plate 61 a of the fixed scroll 61 of the sub-compression mechanism 6. Further, the discharge valve 30 is provided at the tip of the sub-compression discharge port 61e on the upper space 70 side. The discharge valve 30 is opened and closed to communicate / block the sub-compression discharge port 61e and the upper space 70.

Therefore, the refrigerant sucked into the sub compression chamber 6a on the outer peripheral side of the sub compression mechanism 6 via the sub compression suction pipe 12 and the sub compression suction port 61d and compressed and pressurized by the sub compression mechanism 6 is the center of the sub compression mechanism 6. From the sub-compression chamber 6a in the section, it is discharged to the upper space 70 through the sub-compression discharge port 61e, and further discharged to the outside through the sub-compression discharge pipe 14.

A tip seal groove (not shown) is formed on the tip surface of the spiral tooth 61c and the spiral tooth 62c of the sub-compression mechanism 6, and a chip seal 21 for partitioning the sub-compression chamber 6a is attached to the tip seal groove. Further, tip seal grooves (see FIG. 5) are also formed on the tip surfaces of the spiral teeth 51c and the spiral teeth 52c of the expansion mechanism 5, and a chip seal 22 for partitioning the expansion chamber 5a is attached to the chip seal grooves. In the sub compression mechanism 6, an annular outer peripheral seal groove (not shown) is formed on the outer peripheral side of the spiral tooth 61 c on the surface of the fixed scroll 61 facing the swing scroll 52, and the swing scroll is formed in the outer peripheral seal groove. An outer peripheral seal 23 for sealing the sliding contact surface between 62 and the fixed scroll 61 is attached.

An Oldham ring 7 is provided between the fixed scroll 61 and the orbiting scroll 62 of the sub-compression mechanism 6 so as to restrict the rotation motion of the orbiting scroll 52 and the orbiting scroll 62 and enable the revolving motion. Yes. In order to cancel the centrifugal force generated by the revolving motion (oscillating motion) of the swing scroll 52 and the swing scroll 62, a balance weight 9a and a balance weight 9b are attached to both ends of the shaft 8. ing.

In addition, a lower space 72 for storing lubricating oil 80 such as refrigerating machine oil is formed inside the sealed container 10. An oil supply pump 81 for pumping up the lubricating oil 80 is attached to the lower end portion of the shaft 8. The shaft 8 has an oil supply hole 8c extending so as to penetrate in the axial direction, a lateral oil supply hole 8d that communicates with the oil supply hole 8c and opens at one end toward the side surface of the bearing portion 61b of the fixed scroll 61, and an oil supply hole A gas vent hole 8e that communicates with the other end of 8d and extends so as to penetrate the center of the shaft 8 to the upper end is provided.

Further, oil return holes 17 are formed through the annular protrusions 61f provided on the outer periphery of the fixed scroll 61 and the annular protrusions 51f provided on the outer periphery of the fixed scroll 51, respectively. The oil return hole 17 allows the upper space 70 and the lower space 72 to communicate with each other. The oil return hole 17 is provided so as not to pass through the orbiting scroll motion space 71. By forming the oil return hole 17 in each of the annular convex portion 61f and the annular convex portion 51f, the upper space 70 and the lower space 72 communicate with each other, and oil can be returned from the upper space 70 to the lower space 72. It has a possible configuration. Although not shown, the oil return hole 17 is also formed in the rear flange 90.

Therefore, the lubricating oil 80 pumped up by the oil supply pump 81 rises through the oil supply hole 8 c and is supplied from the lateral oil supply hole 8 d to the bearing portion 61 b of the fixed scroll 61 of the sub compression mechanism 6, and below the fixed scroll 61. Are supplied to the orbiting scroll 62 and the eccentric bearing portion 62b of the orbiting scroll 52 and the bearing portion 51b of the fixed scroll 51 sequentially. The gas containing the lubricating oil 80 flows out to the upper space 70 through the gas vent hole 8 e and flows into the lower space 72 through the oil return hole 17.

The liquid injection pipe 18 communicates with the cooling groove 91 formed in the base plate 61a of the fixed scroll 61 described above. The fixed scroll 61 has a rear flange 90 in which a through hole 96 for containing and fitting the bearing portion 61b is formed. In addition to the through hole 96, the rear flange 90 has a cooling groove 91 and a liquid injection pipe. A communication hole 95 serving as an injection flow path that communicates with 18 is formed through (see FIGS. 1 and 3). And the rear flange 90 is installed so that the cooling groove 91 formed in the upper surface (back surface) of the base plate 61a may be covered.

The liquid injection pipe 18 is for injecting high-pressure liquid refrigerant from the circuit side into the sub compression chamber 6a through the communication hole 95, the cooling groove 91 and the liquid injection port 93. That is, the liquid injection pipe 18 is connected to the cooling groove 91 via the communication hole 95. The liquid injection port 93 is formed through the base plate 61a of the fixed scroll 61, and allows the cooling groove 91 and the sub compression chamber 6a to communicate with each other. The reason why the two liquid injection ports 93 are provided is to allow the liquid refrigerant to flow into the two sub compression chambers 6a formed symmetrically.

Further, in order to partition the cooling groove 91 and the upper space 70, an inner peripheral seal 92a and an outer peripheral seal 92b are provided between the upper surface of the base plate 61a and the lower surface of the rear flange 90. The inner peripheral seal 92a and the outer peripheral seal 92b are preferably installed in

seal housing grooves

102a and 102b formed in a ring shape on the upper surface of the base plate 61a. Although the cooling groove 91 and the seal accommodation groove 102 (the seal accommodation groove 102a and the seal accommodation groove 102b) are shown as an example on the upper surface of the base plate 61a, they are formed on the lower surface of the rear flange 90. Needless to say.

Next, the operation of the scroll expander 1 according to Embodiment 1 will be described.
In the expansion mechanism 5, power is generated by expansion of the high-pressure refrigerant sucked from the expansion suction pipe 13 in the expansion chamber 5 a formed by the spiral teeth 51 c of the fixed scroll 51 and the spiral teeth 52 c of the swing scroll 52. appear. The refrigerant expanded and depressurized in the expansion chamber 5a is once discharged into the orbiting scroll motion space 71, and then discharged from the expansion discharge pipe 15 to the outside of the sealed container 10 through the expansion discharge port 51e.

The power generated in the expansion mechanism 5 is transmitted to the sub-compression mechanism 6 through the shaft 8. That is, the oscillating scroll 62 of the sub compression mechanism 6 is rotated by the power generated by the expansion mechanism 5. Then, in the sub compression chamber 6a formed by the spiral teeth 61c of the fixed scroll 61 and the spiral teeth 62c of the swing scroll 62, the refrigerant sucked from the sub compression suction pipe 12 is compressed and pressurized. The refrigerant whose pressure has been increased in the sub compression chamber 6a is discharged from the sub compression discharge port 61e through the discharge valve 30 to the upper space 70 in the sealed container 10 and then passes through the sub compression discharge pipe 14 and then the sealed container. 10 is discharged outside.

Here, the refrigeration cycle apparatus 100 using the scroll expander 1 according to Embodiment 1 will be described. FIG. 4 is a circuit diagram schematically showing a basic configuration of the refrigeration cycle apparatus 100 using the scroll expander 1. The refrigeration cycle apparatus 100 can perform a cooling operation or a heating operation by circulating a refrigerant. As the refrigerant used in the refrigeration cycle apparatus 100, it is assumed that a refrigerant whose high pressure side is supercritical, such as carbon dioxide, is used.

In addition to the scroll expander 1, the refrigeration cycle apparatus 100 is mounted with a main compressor 11, a gas cooler (heat radiator) 2, an expansion valve 3 and an evaporator 4 connected by piping. The main compression mechanism 11a driven by the electric mechanism 11b of the main compressor 11 is connected to the front stage (upstream side) of the sub-compression mechanism 6 driven by the expansion mechanism 5 of the scroll expander 1, and the main compression mechanism 11a An evaporator 4 for heating the refrigerant is connected to the previous stage (upstream side). That is, the sub compression mechanism 6 of the scroll expander 1 is connected to the discharge side of the main compression mechanism 11 a of the main compressor 11.

On the other hand, a gas cooler 2 for cooling the refrigerant is connected to the rear stage (downstream side) of the sub-compression mechanism 6, and the expansion mechanism 5 of the scroll expander 1 and the expansion are connected to the rear stage (downstream side) of the gas cooler 2. The valve 3 (throttle device) is connected in parallel. Although not shown, the sub-compression mechanism 6 of the scroll expander 1 may be connected to the suction side of the main compression mechanism 11a of the main compressor 11.

The main compressor 11 includes a main compression mechanism 11a and an electric mechanism 11b, and sucks refrigerant and compresses the refrigerant to a high temperature / high pressure state. Configure. The gas cooler 2 performs heat exchange between air and a refrigerant that are forcibly supplied from a blower such as a fan (not shown). The expansion valve 3 expands the refrigerant by depressurizing it, and may be configured with a valve whose opening degree can be variably controlled, such as an electronic expansion valve. The evaporator 4 performs heat exchange between air and a refrigerant that are forcibly supplied from a blower such as a fan (not shown).

The operation of the refrigeration cycle apparatus 100 will be described.
When the main compression mechanism 11a of the main compressor 11 is driven by the electric mechanism 11b, the pressure of the refrigerant is increased by the main compression mechanism 11a. The pressurized refrigerant is discharged from the main compressor 11, flows into the sub compression mechanism 6 of the scroll expander 1, and is further pressurized by the sub compression mechanism 6. The refrigerant whose pressure has been increased by the sub compression mechanism 6 is discharged from the sub compression mechanism 6 and flows into the gas cooler 2. The refrigerant that has flowed into the gas cooler 2 is cooled by the gas cooler 2, and then a part of the refrigerant is sent to the expansion mechanism 5 of the scroll expander 1, where it is decompressed and decompressed.

On the other hand, the remaining refrigerant cooled by the gas cooler 2 is sent to the expansion valve 3 and decompressed and decompressed. The expansion valve 3 is provided in parallel with the expansion mechanism 5 of the scroll expander 1 in order to adjust the flow rate passing through the expansion mechanism 5 and ensure the differential pressure at the time of activation. In the expansion mechanism 5, the refrigerant expands in an isentropic manner, whereby expansion power is transmitted from the expansion mechanism 5 to the sub-compression mechanism 6 through the shaft 8 and is used as sub-compression work. The refrigerant expanded by the expansion mechanism 5 is heated by the evaporator 4 and then returns to the main compression mechanism 11a of the main compressor 11 again.

FIG. 5 is a schematic cross-sectional view schematically showing the expansion mechanism 5 and the sub-compression mechanism 6 of the scroll expander 1. Based on FIG. 5, the pressure acting on the orbiting scroll 52 and the orbiting scroll 62 will be described. The arrows shown in FIG. 5 represent the distribution of axial differential pressure acting on the orbiting scroll 52 and the orbiting scroll 62 with the low pressure Pl as a reference. Further, Ph indicates a high pressure, Pm indicates an intermediate pressure, and Pl indicates a low pressure. In FIG. 1, the tip seal is not shown in the expansion mechanism 5, but the tip seal is also provided in the expansion mechanism 5 as shown in FIG. 5.

In the scroll expander 1, the expansion mechanism 5 is responsible for the expansion process from the high pressure Ph to the low pressure Pl, and the sub-compression mechanism 6 is responsible for the compression process from the intermediate pressure Pm to the high pressure Ph. Therefore, in the orbiting scroll 52 and the orbiting scroll 62, the high pressure Ph acts on both the central expansion chamber 5a and the central sub-compression chamber 6a, and the low pressure Pl is applied to the outer expansion chamber 5a. The intermediate pressure Pm acts on the sub compression chamber 6a at the outer peripheral portion.

The refrigerant compressed by the sub-compression mechanism 6 is discharged from the sub-compression discharge port 61e through the discharge valve 30 to the upper space 70 in the sealed container 10 and then to the outside of the sealed container 10. The lower space 72 has the same compressed pressure as the upper space 70 through the oil return hole 17 that does not pass through the orbiting scroll motion space 71. As described above, the oil return hole 17 includes the rear flange 90, the annular convex portion 61f provided on the outer peripheral portion of the base plate 61a of the fixed scroll 61, and the annular convex portion provided on the outer peripheral portion of the base plate 51a of the fixed scroll 51. A penetrating hole 51f is formed.

On the other hand, the refrigerant expanded by the expansion mechanism 5 is opened to the orbiting scroll motion space 71 and discharged to the outside of the sealed container 10 through the expansion discharge pipe 15. The outer peripheral portion of the sub-compression mechanism 6 that becomes the intermediate pressure Pm and the orbiting scroll motion space 71 is sealed by the outer peripheral seal 23, and the inside of the orbiting scroll motion space 71 is the pressure after expansion.

The differential pressure at the center of the orbiting scroll 52 and the orbiting scroll 62 is equal to Ph−Pl on both the expansion mechanism 5 side and the sub-compression mechanism 6 side. However, the differential pressure at the outer peripheral portions of the orbiting scroll 52 and the orbiting scroll 62 is 0 on the expansion mechanism 5 side and Pm−Pl on the sub compression mechanism 6 side. The orbiting scroll 52 and the orbiting scroll 62 are integrated with screws or the like, and the thrust load F acting on the orbiting scroll 52 and the orbiting scroll 62 is obtained by integrating this differential pressure. The thrust load F acting on the orbiting scroll 52 and the orbiting scroll 62 can be adjusted so as not to become excessive by adjusting the diameter and the cross-sectional diameter of the outer peripheral seal 23 provided in the sub-compression mechanism 6. Is possible.

FIG. 6 is a Mollier diagram showing changes in the state quantity of the refrigerant in the refrigeration cycle apparatus 100 using the scroll expander 1. In FIG. 6, the vertical axis represents pressure P, the horizontal axis represents enthalpy h, and the broken line represents an isotherm.

As shown in FIG. 6, the refrigerant cooled from the point d to the point c by exchanging heat with the gas cooler 2 is, for example, from the point c to the point b ′ in a decompression mechanism using a throttle such as the expansion valve 3. It expands enthalpyly. On the other hand, the expansion mechanism 5 expands the refrigerant from point c to point b by expanding in an isentropic manner. Therefore, it is possible to recover the expansion power by the difference hb'-hb between the enthalpy hb 'at the point b' and the enthalpy hb at the point b. After being expanded by the scroll expander 1, the refrigerant gas that is heat-exchanged by the evaporator 4 and heated from the point b to the point a is compressed by the main compression mechanism 11 a of the main compressor 11 from the point a to the point d ′. After that, the sub-compression mechanism 6 of the scroll expander 1 is compressed from the point d ′ to the point d.

As described above, in the refrigeration cycle apparatus 100, the main compression mechanism 11a of the main compressor 11 bears a part of the compression process of the refrigeration cycle, and the sub-compression mechanism 6 of the scroll expander 1 stores the remaining part of the compression process. Is responsible. The compression power corresponding to the enthalpy difference hd−hd ′ in the sub-compression mechanism 6 is provided by the recovery power corresponding to hb′−hb.

Here, assuming that the temperatures of point b, point c, point d, and point d 'in FIG. 6 are Tb, Tc, Td, and Td', respectively, Tb <Tc <Td '<Td. That is, the expansion mechanism 5 is distributed from low temperature Tc to Tb, and the sub-compression mechanism 6 is distributed from high temperature Td 'to Td. Since the scroll expander 1 integrates the sub-compression mechanism 6 and the expansion mechanism 5 back to back, the base plate 52a of the orbiting scroll 52 and the orbiting scroll are caused by the temperature difference between the sub-compression mechanism 6 and the expansion mechanism 5. Heat leakage occurs through the base plate 62a of 62. Further, even when the refrigerant gas after expansion passes through the expansion discharge port 51 e provided in the fixed scroll 61, a heat leak occurs due to a temperature difference with the base plate 61 a of the fixed scroll 61.

FIG. 7 is a Mollier diagram showing the refrigerant state quantity change in the refrigeration cycle apparatus 100 when the amount of heat leak from the sub-compression mechanism 6 to the expansion mechanism 5 is large.

As shown in FIG. 7, when the temperature of the expansion mechanism 5 rises due to heat leak, the discharge point of the expansion mechanism 5 moves from the point b to the point bb, and the discharge point of the sub compression mechanism 6 moves from the point d to the point dd. To do. That is, the enthalpy difference of the evaporator 4 and the enthalpy difference of the gas cooler 2 are reduced compared to when the heat leak is small, and the cooling capacity and the heating capacity are reduced.

Therefore, in the scroll expander 1, a cooling groove 91 connected to the liquid injection pipe 18 is provided between the fixed scroll 61 of the sub compression mechanism 6 and the rear flange 90, and the cooling groove 91 communicates with the sub compression chamber 6a. A liquid injection port 93 is provided. The liquid refrigerant flowing in from the liquid injection pipe 18 is injected into the sub compression chamber 6a after passing through the cooling groove 91 provided on the back surface (upper surface) of the fixed scroll. Therefore, the liquid refrigerant is evaporated in the sub compression chamber 6a. In addition to cooling, the fixed scroll 61 is cooled by the liquid refrigerant in the cooling groove 91.

Therefore, according to the scroll expander 1, the heat leak via the expansion discharge port 51e provided on the outer peripheral portion of the fixed scroll 61 can be reduced, and the liquid refrigerant remains little even if a large amount of liquid refrigerant is introduced. Since compression is less likely to occur, the cooling amount itself can be increased, and further heat leakage can be reduced.

The inner peripheral seal 92a and the outer peripheral seal 92b are provided around the cooling groove 91. However, in the first embodiment, even if the liquid refrigerant leaks into the upper space 70 on the downstream side, the sub-compressed discharge gas is cooled. As a result, the efficiency of the sub-compressor is not affected and the liquid injection flow path is partitioned. Accordingly, the cost can be reduced by omitting the inner peripheral seal 92a and the outer peripheral seal 92b. Further, since the sub-compression discharge temperature is lowered, the inlet / outlet enthalpy difference of the gas cooler 2 is reduced, but the heating capacity is not lowered because the refrigerant circulation amount is increased by the liquid injection.

According to the above configuration, the amount of heat leak from the sub-compression mechanism 6 to the expansion mechanism 5 is the back-to-back configuration capable of reducing the thrust load F acting on the orbiting scroll 52 and the orbiting scroll 62. Therefore, it is possible to obtain a high-performance scroll expander with a small reduction in capacity under a wide range of operating conditions. Moreover, according to the refrigerating cycle apparatus 100, since the scroll expander 1 is provided, an operation with high cycle efficiency can be realized.

In the first embodiment, the configuration is shown in which the shaft 8 passes through the center of the rocking scroll 52 and the rocking scroll 62 and is supported by both ends, and the rocking motion is performed. An external drive configuration in which the shaft 8 is provided outside the 62 may be employed. With such an external drive configuration, the cooling groove 91 can be provided in the central portion where the temperature difference is large, so that the amount of cooling can be further increased, and heat leakage can be suppressed.

Embodiment 2. FIG.
FIG. 8 is a top view (a) and a cross-sectional view (b) of the fixed scroll 61A of the sub-compression mechanism 6 of the scroll expander according to Embodiment 2 of the present invention. Based on FIG. 8, the fixed scroll 61A of the sub compression mechanism 6 of the scroll expander according to the second embodiment will be described. The scroll expander according to the second embodiment is an integrated scroll type expander and compressor similar to the scroll expander 1 according to the first embodiment, and the expansion power generated when the refrigerant expands. It has a function of collecting and compressing the refrigerant using the recovered expansion power. In the second embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and differences from the first embodiment will be mainly described.

In the scroll expander 1 according to the first embodiment, the cooling groove 91 is formed so as to have a ring shape, but in the scroll expander according to the second embodiment, not only the cooling groove 91 is formed so as to have a ring shape. A partition wall 94 is provided for each liquid injection port 93 to partition the inside of the cooling groove 91. In addition, in the scroll expander according to the second embodiment, the injection pipes 18 (specifically, the communication holes 95) are located away from the respective liquid injection ports 93, that is, in the vicinity of the partition walls 94 of the partitioned cooling grooves 91. A plurality of are provided. Thereby, as shown by the arrows in the figure, the liquid refrigerant flows without drifting in the plane of the cooling groove 91 of the fixed scroll 61 and the heat transfer surface can be made larger, so that the cooling effect can be further improved.

In the second embodiment, as in the first embodiment, it is assumed that the shaft 8 passes through the center of the rocking scroll 52 and the rocking scroll 62 and is supported by both ends so as to swing. However, an external drive configuration in which the shaft 8 is provided outside the rocking scroll 52 and the rocking scroll 62 may be employed. With such an external drive configuration, the cooling groove 91 can be provided in the central portion where the temperature difference is large, so that the amount of cooling can be further increased, and heat leakage can be suppressed. Needless to say, the scroll expander according to the second embodiment can be applied to the refrigeration cycle apparatus 100 described in the first embodiment.

Embodiment 3 FIG.
FIG. 9 is a circuit diagram schematically showing a basic configuration of a refrigeration cycle apparatus 100A according to Embodiment 3 of the present invention. Similar to the refrigeration cycle apparatus 100, the refrigeration cycle apparatus 100A can perform a cooling operation or a heating operation by circulating a refrigerant. As the refrigerant used in the refrigeration cycle apparatus 100A, it is assumed that a refrigerant whose high pressure side is supercritical, such as carbon dioxide, is used. The refrigeration cycle apparatus 100A is equipped with the scroll expander according to the first embodiment or the second embodiment.

In the refrigeration cycle apparatus 100 described above, the sub-compression mechanism 6 of the scroll expander 1 is shown as an example connected in series to the discharge side of the main compression mechanism 11a of the main compressor 11, but in the refrigeration cycle apparatus 100A, As shown in FIG. 9, the sub compression mechanism 6 and the second compressor 24 are provided in parallel on the discharge side of the main compression mechanism 11a. Also in this configuration, the temperature difference between the sub-compression mechanism 6 and the expansion mechanism 5 is large, and it is possible to realize a reduction in heat leak as in the first embodiment. With such a configuration, the second compressor 24 absorbs the change in flow rate under operating conditions that deviate from the design point of the scroll expander 1, whereby flow rate matching can be achieved, and waste of expansion power can be suppressed. Efficient operation can be realized.

Embodiment 4 FIG.
FIG. 10 is a circuit diagram schematically showing a basic configuration of a refrigeration cycle apparatus 100B according to Embodiment 4 of the present invention. Similar to the refrigeration cycle apparatus 100 and the refrigeration cycle apparatus 100A, the refrigeration cycle apparatus 100B can perform a cooling operation or a heating operation by circulating a refrigerant. As the refrigerant used in the refrigeration cycle apparatus 100B, it is assumed that a refrigerant whose high pressure side is supercritical, such as carbon dioxide, is used. The refrigeration cycle apparatus 100B is equipped with the scroll expander according to the first embodiment or the second embodiment.

In the refrigeration cycle apparatus 100 and the refrigeration cycle apparatus 100A described above, the state in which the scroll expander 1 is arranged on the higher stage side of the main compressor 11 is shown as an example. In the refrigeration cycle apparatus 100B, as shown in FIG. It is provided on the lower stage side in parallel with the compression mechanism 11a. When the scroll expander 1 is arranged on the low stage side in parallel with the main compression mechanism 11a, the effect of heat leak is small because it normally operates in a low temperature range. However, in this embodiment, the amount of pressure increase is determined by the balance between the recovered power from the expansion mechanism 5 and the flow rate branched to the sub-compressor side, and may increase to a high pressure depending on the operating conditions. Thus, the same effect as in the third embodiment can be obtained.

As described above, in the first to fourth embodiments, the case where the cooling groove 91 is provided in the base plate 61a of the fixed scroll 61 has been described as an example. However, as shown in FIG. You may inject directly into the sub compression chamber 6a via the liquid injection port 93. FIG. If the scroll expander 1 is configured in this way, there is an effect that the number of parts can be further reduced as compared with those described in the first to fourth embodiments.

In Embodiments 1 to 4 described above, the case where carbon dioxide is used as the refrigerant has been described as an example. However, the type of refrigerant is not limited to carbon dioxide. 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.).

1 scroll expander, 2 gas cooler, 3 expansion valve, 4 evaporator, 5 expansion mechanism, 5a expansion chamber, 6 sub compression mechanism, 6a sub compression chamber, 7 Oldham ring, 8 shaft, 8b crank part, 8c oiling hole, 8d oil supply hole, 8e gas vent hole, 9a balance weight, 9b balance weight, 10 sealed container, 11 main compressor, 11a main compression mechanism, 11b electric mechanism, 12 sub compression suction pipe, 13 expansion suction pipe, 14 sub compression discharge Pipe, 15 expansion discharge pipe, 17 oil return hole, 18 liquid injection pipe, 21 tip seal, 22 tip seal, 23 outer peripheral seal, 24 second compressor, 30 discharge valve, 51 fixed scroll, 51a base plate, 51b bearing part , 51c spiral teeth, 51d expansion suction port, 51e expansion discharge port , 51f annular convex part, 52 swing scroll, 52a base plate, 52c spiral tooth, 61 fixed scroll, 61A fixed scroll, 61a base plate, 61b bearing part, 61c spiral tooth, 61d sub compression suction port, 61e sub compression discharge port , 61f annular convex part, 62 rocking scroll, 62a base plate, 62b eccentric bearing part, 62c spiral tooth, 70 upper space, 71 rocking scroll motion space, 72 lower space, 80 lubricating oil, 81 oil pump, 90 rear flange 91 cooling groove, 92a inner peripheral seal, 92b outer peripheral seal, 93 liquid injection port, 94 partition wall, 95 communication hole, 96 through hole, 100 refrigeration cycle apparatus, 100A refrigeration cycle apparatus, 100B refrigeration cycle apparatus, 102a seal housing groove, 102b Seal housing groove.

Claims

An expansion mechanism that forms an expansion chamber with the first swing scroll and the first fixed scroll, and expands the refrigerant sucked into the expansion chamber to recover power;
A sub-compression chamber is formed by the second orbiting scroll and the second fixed scroll that are integrally formed with the first orbiting scroll, and the power collected by the expansion mechanism is used for the refrigerant sucked into the sub-compression chamber. A sub-compression mechanism for compressing
A scroll expander having a closed container that houses the expansion mechanism and the sub-compression mechanism,
A scroll expander characterized in that a liquid injection port capable of injecting liquid refrigerant from outside the sealed container into the sub compression chamber is provided in the second fixed scroll.
A rear flange is disposed on the side surface of the second fixed scroll opposite to the second orbiting scroll;
Forming a cooling space between the second fixed scroll and the rear flange;
A liquid injection flow path for guiding the liquid refrigerant from outside the sealed container to the cooling space is provided in the rear flange,
The scroll expander according to claim 1, wherein the liquid injection port is communicated with the injection flow path through the cooling space.
The cooling space is
The scroll expander according to claim 2, wherein the scroll expander is a notch groove formed in an upper surface of the second fixed scroll or a lower surface of the rear flange.
The scroll expander according to claim 2 or 3, wherein a seal member that partitions the cooling space and the space in the sealed container is provided around the cooling space.
A plurality of the liquid injection ports are provided,
A partition is provided in the cooling space, and the cooling space is partitioned for each liquid injection port.
The scroll expander according to any one of claims 1 to 4, wherein the liquid injection flow path is provided for each of the partitioned cooling spaces.
Of the liquid injection port and the injection flow path communicating with one cooling air path,
The liquid injection port is provided in the vicinity of one of the partition walls constituting the cooling space,
The scroll expander according to claim 5, wherein the injection flow path is provided in the vicinity of the other of the partition walls constituting the cooling space.
The scroll expander according to any one of claims 1 to 6, a main compressor, a gas cooler, a throttling device, and an evaporator,
Connecting the sub-compression mechanism to the discharge side of the main compressor;
The refrigeration cycle apparatus, wherein the expansion mechanism is connected between the gas cooler and the evaporator so that the expansion devices are arranged in parallel.
The refrigeration cycle apparatus according to claim 7, wherein a second compressor is provided on the discharge side of the main compressor so as to be in parallel with the sub-compression mechanism.
The scroll expander according to any one of claims 1 to 6, a main compressor, a gas cooler, a throttling device, and an evaporator,
Connecting the sub-compression mechanism to the suction side of the main compressor;
The refrigeration cycle apparatus, wherein the expansion mechanism is connected to a downstream side of the expansion device.