KR20230100184A - Gas Cycle Heat Pump with Cooling Path - Google Patents

Abstract

The present invention relates to a gas cycle heat pump provided with a cooling path. The gas cycle heat pump, which is a mechanism for transferring heat from one spot to another spot, includes: a compression unit provided with a compression gas path connected from a compressed gas inlet to a compressed gas outlet; an expanded gas inlet into which gas which is a refrigerant to be expanded is suctioned; a turbine wheel rotated by the gas introduced through the expanded gas inlet; an expanded gas outlet from which the gas having passed through the turbine wheel is discharged; an expansion unit provided with an expanded gas path connected from the expanded gas inlet to the expanded gas outlet; a motor provided with a rotary shaft having one end coupled to the impeller such that relative rotation is not possible, and having the other end coupled to the turbine wheel such that relative rotation is not possible; a housing having a motor housing space to house the motor; and a cooling path provided to pass through the motor housing space, and provided to enable some of the gas introduced through the expanded gas inlet to function as cooling gas for cooling the motor. In accordance with the present invention, the gas cycle heat pump can have an effect of utilizing a portion of a refrigerant as cooling gas without using separate cooling gas.

Description

Gas cycle heat pump with cooling path {Gas Cycle Heat Pump with Cooling Path}

The present invention relates to a gas cycle heat pump, and more particularly, to a gas cycle heat pump capable of using a part of a refrigerant as a cooling gas without using a separate cooling gas.

A heat pump is a mechanical device that absorbs heat from a low-temperature heat source and transports the heat to a high-temperature heat source. .

A conventional heat pump has been developed to supply cooling and heating based on a refrigerant cycle using a refrigerant such as hydrofluorocarbon (HFC). However, due to environmental problems, regulations on refrigerants such as hydrofluorocarbons (HFC) are being strengthened, and the structure is complicated to prevent leakage of harmful refrigerants, and there is a problem that difficulties in refrigerant management such as refrigerant filling always exist. .

In order to solve these problems, eco-friendly heat pump products consisting of a gas cycle using air instead of a hydrofluorocarbon (HFC)-based refrigerant are being developed, and some products are reaching the commercialization stage. .

As shown in FIGS. 7 and 8 , a heat pump using a gas cycle connects a compressor 1 and an expander 3 with one shaft and exchanges heat with a high-temperature heat exchanger 2 and a low-temperature heat exchanger. After configuring the gas cycle system by adding the group 4, it has a method of cooling the external heat source 6 or heating the external heat source 5.

That is, the overall circulation process of the gas cycle is: i) a compression process (a→b) in which the air is compressed in the compressor 1 and the pressure and temperature rise (a → b), and ii) the compressed high-pressure, high-temperature air is transferred to the high-temperature heat exchanger In (2), heat is transferred to the external heat source (5), and the temperature is lowered in a constant pressure condition (b → c), and iii) the air whose temperature has decreased is expanded in the expander (3), thereby reducing the pressure Expansion process (c → d) in which the temperature and temperature decrease, and iv) Temperature rise in which the temperature and pressure are decreased by taking heat from the external heat source (6) in the low-temperature heat exchanger (4) and increasing its temperature under the condition of constant pressure It consists of the process (d → a).

At this time, in the compression process (a → b), the compression work (W _c ) is required to drive the compressor, and in the expansion process (c → d), since the expansion work (W _t ) is generated from the expander, this expansion work (W By returning _t ) to the compressor, power (W _input ) required for driving the compressor 1 can be reduced.

In addition, in the temperature decreasing process (b→c) or temperature rising process (d→a), the external heat sources 5 and 6 correspond to the air-conditioning space, and therefore, in this process, heat is released to the air-conditioning space or heat is absorbed to control the air conditioning. It serves to heat or cool the space.

The power (W _input ) necessary for driving the compressor may be provided by various types of motors, but due to the operating characteristics of the heat pump, continuous driving of the motor is required for a very long time. After all, in the case of a heat pump, high heat is inevitably continuously generated in the motor and its attached bearings, so an efficient cooling structure for the motor, bearings, etc., which are main heat sources, is essential.

The present invention has been made to solve the above problem, and its object is to provide a gas cycle heat pump having an improved structure so that a part of a refrigerant can be used as a cooling gas without using a separate cooling gas.

In order to achieve the above object, a gas cycle heat pump according to the present invention is a device capable of transferring heat from one point to another, comprising: a compressed gas inlet through which gas, which is a refrigerant to be compressed, is sucked; an impeller for compressing the gas introduced through the compressed gas inlet; a compressed gas outlet through which the gas compressed by the impeller is discharged to the outside; a compression unit having a compressed gas flow path connected from the compressed gas inlet to the compressed gas outlet; an expansion gas inlet through which gas, which is a refrigerant to be expanded, is sucked; a turbine wheel that can be rotated by the gas introduced through the expansion gas inlet; an expansion gas outlet through which the gas passing through the turbine wheel is discharged to the outside; an expansion unit having an expansion gas flow path connected from the expansion gas inlet to the expansion gas outlet; a motor having a rotational shaft having one end coupled non-rotatably with the impeller and the other end non-rotatably coupled with the turbine wheel; a housing having a motor accommodating space accommodating the motor; and a cooler provided to pass through the motor accommodating space and provided so that a part of the gas introduced through the expansion gas inlet can function as a cooling gas capable of cooling the motor.

Here, it is preferable that the gas for cooling flowing along the cooling passage passes through the turbine wheel after joining the expansion gas passage upstream of the turbine wheel.

Here, the cooling gas flowing along the cooling passage may be discharged to the outside of the housing through a cooling gas outlet formed in the motor accommodating space.

Here, it is preferable that the compressed gas passage is spatially separated from the cooling passage so that gas inside the compressed gas passage cannot penetrate into the cooling passage.

Here, it is preferable that at least one non-contact bearing supporting a load in a radial direction or an axial direction of the rotation shaft is mounted on at least one of both ends of the rotation shaft.

Here, the cooling passage preferably includes a passage penetrating the housing so as to cool the housing.

Here, the housing includes an inner housing having a space for accommodating the motor; and an outer housing surrounding the inner housing, and the cooling passage preferably includes a passage provided between an outer surface of the inner housing and an inner surface of the outer housing.

Here, the refrigerant gas preferably contains more than a predetermined amount of air.

According to the present invention, an apparatus capable of transferring heat from one point to another, comprising: a compression unit having a compressed gas flow path connected from a compressed gas inlet to a compressed gas outlet; an expansion gas inlet through which gas, which is a refrigerant to be expanded, is sucked; a turbine wheel that can be rotated by the gas introduced through the expansion gas inlet; an expansion gas outlet through which the gas passing through the turbine wheel is discharged to the outside; an expansion unit having an expansion gas flow path connected from the expansion gas inlet to the expansion gas outlet; a motor having a rotational shaft having one end coupled non-rotatably with the impeller and the other end non-rotatably coupled with the turbine wheel; a housing having a motor accommodating space accommodating the motor; A cooler provided to pass through the motor accommodating space and provided so that a part of the gas introduced through the expansion gas inlet can function as a cooling gas capable of cooling the motor; There is an effect that a part of the refrigerant to be expanded without using gas can be used as a gas for cooling.

1 is a perspective view of a heat pump that is a first embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along line II-II of the heat pump shown in FIG. 1 .
FIG. 3 is a partially enlarged view of the heat pump shown in FIG. 2 .
FIG. 4 is a partially enlarged view of the heat pump shown in FIG. 3 .
5 is a cross-sectional view of a heat pump according to a second embodiment of the present invention.
FIG. 6 is a partially enlarged view of the heat pump shown in FIG. 5 .
7 is a schematic configuration diagram of a general gas cycle.
FIG. 8 is a TS diagram of the gas cycle shown in FIG. 7 .

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a perspective view of a heat pump according to a first embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along line II-II of the heat pump shown in FIG. 1 . FIG. 3 is a partially enlarged view of the heat pump shown in FIG. 2 .

1 to 3, the gas cycle heat pump 100 according to the first preferred embodiment of the present invention absorbs heat from one heat source 6 as shown in FIG. ) As a device capable of transferring heat, it is composed of a housing 10, a compression unit 20, a motor 30, an expansion unit 40, and a cooling passage 14. Hereinafter, the left side of FIG. 2 is expressed as the front and the right side of FIG. 2 is expressed as the rear, and description will be made on the premise that the refrigerant gas is 100% pure air.

Since the gas cycle heat pump 100 has the form of a single assembly in which the compression unit 20 and the expansion unit 40 are integrally coupled to the housing 10 as shown in FIG. 1, the compressor It can be referred to as "compander", a coined word combining the words "compressor" and "expander".

The housing 10 is a housing made of a metal material, and includes an outer housing 11 and an inner housing 12 .

The outer housing 11 is a cylindrical member having a cross section with the first central axis C1 as a center of a circle, and extends along the first central axis C1.

The outer housing 11 has a shape corresponding to the inner housing 12 so as to accommodate the inner housing 12 in a wrapped state.

The inner surface of the outer housing 11 and the outer surface of the inner housing 12 face each other while being spaced apart by a predetermined distance.

The inner housing 12 is a cylindrical member having a motor accommodating space 13 therein, and has a cross section with a first central axis C1 as a center of a circle, along the first central axis C1. has been extended

The motor accommodating space 13 is a space having a shape corresponding to the motor 30 to accommodate the motor 30 to be described later.

As shown in FIG. 2 , the inner housing 12 has a circular pipe shape with left and right ends open.

On the outer surface of the inner housing 12, as shown in FIG. 2, a plurality of cooling fins 111 are arranged along the first central axis C1.

In this embodiment, the cooling fin 111 is provided in a circular annular shape with the first central axis C1 as the center of a circle.

The compression unit 20 is a device for sucking in and compressing external air, and includes an impeller 21 , an outer cover 22 , and an inner cover 23 .

The impeller 21 is a wheel equipped with a plurality of wings having a curved surface as a main component of a centrifugal pump, and is mounted to enable high-speed rotation.

The outer cover 22 is a metal member disposed in front of the impeller 21 and has a compressed gas inlet 24 through which external air is sucked in.

The outer cover 22 is provided in the form of a scroll casing having a flow path formed so that the air passing through the impeller 21 can flow in a spiral shape.

The inner cover 23 is a metal member disposed behind the impeller 21 and is coupled to the housing 10 by bolts or screws.

The impeller 21 is a member that compresses the air introduced through the compressed gas inlet 24, and the air compressed by the impeller 21 is discharged to the outside through the compressed gas outlet 25.

The air sucked into the compressed gas inlet 24 is compressed while moving along the compressed gas passage 26 connected from the compressed gas inlet 24 to the compressed gas outlet 25, and the compressed gas flow CF will form

The motor 30 is an electric motor that generates rotational force and is a device for supplying high-speed rotational force to the impeller 21 . The motor 30 includes a rotating shaft 31, a stator 32, a rotor 33, a journal bearing 34, and a thrust bearing 35.

The rotating shaft 31 is a rod member extending along the first central axis C1, and has a front end coupled to the impeller 21 so as not to rotate relative to each other in order to rotate the impeller 21.

The rear end of the rotary shaft 31 is coupled to a turbine wheel 41 of an expansion unit 40 to be described later and non-rotatably.

The stator 32 is a stator around which a field coil is wound, and is mounted in the motor accommodating space 13 in a fixed state.

The rotor 33 is a rotor including a permanent magnet, and is coupled to an intermediate portion of the rotating shaft 31 .

The journal bearing 34 is a type of non-contact bearing as an air bearing for supporting a load in the radial direction of the rotation shaft 31, rotatably supports the rotation shaft 31, and a pair is provided to support the rotation shaft 31 are respectively disposed at the front and rear ends of the

The thrust bearing 35 is a type of non-contact bearing as an air bearing for supporting the load of the rotation shaft 31 in the axial direction (C1), rotatably supports the rotation shaft 31, and A pair is disposed at the rear end of

Between the stator 32 and the rotor 33, between the rotating shaft 31 and the stator 32, and between the rotating shaft 31 and the bearings 34 and 35, there are predetermined intervals, respectively. do.

The expansion unit 40 is a device for inhaling and expanding external air, and includes a turbine wheel 41, an outer cover 42, and an inner cover 43.

The turbine wheel 41 is a wheel equipped with a plurality of wings having a curved surface as a main component of a centrifugal expander, and is mounted to enable high-speed rotation.

The turbine wheel 41 is provided to be rotated by air force of air sucked through an expansion gas inlet 44 to be described later.

The outer cover 42 is a metal member disposed behind the turbine wheel 41, and has an expansion gas outlet 45 provided to discharge air passing through the turbine wheel 41 to the outside.

Inside the outer cover 42, an expansion gas storage space 441 is formed so that air sucked in from the outside through the expansion gas inlet 44 can stay for a while.

At one end of the expansion gas storage space 441, as shown in FIG. 1, an expansion gas inlet 44 is formed so that air can be sucked in from the outside.

The inner cover 43 is a metal member disposed in front of the turbine wheel 41 and is coupled to the housing 10 by bolts or screws.

A turbine nozzle 47 is formed between the outer cover 42 and the inner cover 43 so that air accommodated in the expansion gas storage space 441 can be accelerated and expanded.

The turbine nozzle 47 is a nozzle disposed upstream of the turbine wheel 41 and is provided to accelerate air.

Air that is accelerated and expanded while passing through the turbine nozzle 47 passes through the turbine wheel 41 and then is discharged to the outside through the expansion gas outlet 45 .

The air sucked into the expansion gas inlet 44 moves along the expansion gas passage 46 connected from the expansion gas inlet 44 to the expansion gas outlet 45 while expanding the expansion gas flow EF. will form At this time, the turbine wheel 41 receives a constant rotational force by the air force of the expansion gas flow EF.

The cooling passage 14 is a passage provided to cool the motor 30 and the bearings 34 and 35 while the cooling gas G flows, and as shown in FIG. 3, the motor accommodating space ( 13) is provided inside.

A part of the air received in the expansion gas storage space 441 after being introduced through the expansion gas inlet 44 is used as cooling gas G for cooling the motor 30 and the like.

It is appropriate that about 3 to 10% of the air introduced through the expansion gas inlet 44 is used as the cooling gas G, and in this embodiment, the air introduced through the expansion gas inlet 44 5% of is used as gas (G) for cooling.

The cooling passage 14 is provided to pass through the motor accommodation space 13 and the housing 10 as shown in FIG. ), and a rear end group 14d.

The outer air passage 14a is a air passage penetrating the housing 10 to cool the housing 10, and extends around the first central axis C1.

As shown in FIG. 3 , the outer group 14a is formed by an outer circumferential surface of the inner housing 12 and an inner circumferential surface of the outer housing 11 .

The front end passage 14b is a passage provided to allow cooling gas to flow from the outer edge of the front end of the inner housing 12 toward the center of the inner housing 12 .

The shearing airway 14b extends from the front end of the outside airway 14a to the motor accommodating space 13 and may pass through a part of the inner housing 12 .

The inner air passage 14c is provided so that gas for cooling can pass through the field coil of the stator 32, the rotating shaft 31, the rotor 33, and the bearings 34 and 35 .

The front end of the inner airway 14c communicates with the front airway 14b, and the rear end of the inner airway 14c communicates with the rear airway 14d to be described later.

The rear air passage 14d is a air passage provided so that the cooling gas can flow from the center of the rear end of the inner housing 12 toward the radial direction of the inner housing 12 .

In this embodiment, the rear end airway 14d is a disk-shaped space provided between the outer surface of the inner housing 12 and the surface of the turbine wheel 41, and the turbine nozzle through the cooling gas outlet 142 It is in communication with (47).

As shown in FIG. 4 , the cooling gas outlet 142 is a hole formed in the inner cover 43 and is located near the maximum diameter of the turbine wheel 41 .

The cooling furnace 14 is preferably arranged rotationally or axially symmetrically around the first central axis C1.

A part of the air accommodated in the expansion gas storage space 441 is introduced into the outer air passage 14a through the cooling gas inlet 141 formed in the inner cover 43 as shown in FIG. 4 .

After sequentially flowing through the cooling passages 14a, 14b, 14c, and 14d, the air flowing out to the turbine nozzle 47 through the cooling gas outlet 142 has a sufficiently low pressure, so that the turbine wheel 41 After joining the expansion gas flow EF at the turbine nozzle 47 located upstream of ), it passes through the turbine wheel 41.

In this embodiment, the cooling passage 14 is spatially separated from the compressed gas passage 26 . Accordingly, the air inside the compressed gas passage 26 cannot leak from the compressed gas passage 26 and penetrate into the cooling passage 14 in the process of being compressed.

The gas cycle heat pump 100 having the above configuration is a device capable of transferring heat from one point to another, and includes a compressed gas inlet 24 into which gas, which is a refrigerant to be compressed, is sucked; an impeller 21 for compressing the gas introduced through the compressed gas inlet 24; a compressed gas outlet 25 through which the gas compressed by the impeller 21 is discharged to the outside; a compression unit (20) having a compressed gas passage (26) connected from the compressed gas inlet (24) to the compressed gas outlet (25); an expansion gas inlet 44 into which gas, which is a refrigerant to be expanded, is sucked; a turbine wheel 41 that can be rotated by the gas introduced through the expansion gas inlet 44; an expansion gas outlet 45 through which the gas passing through the turbine wheel 41 is discharged to the outside; an expansion unit (40) having an expansion gas passage (46) connected from the expansion gas inlet (44) to the expansion gas outlet (45); A motor 30 having a rotating shaft 31 having one end coupled non-rotatably to the impeller 21 and the other end non-rotatably coupled to the turbine wheel 41; a housing 10 having a motor accommodating space 13 accommodating the motor 30; It is provided to pass through the motor accommodating space 13, and a part of the gas introduced through the expansion gas inlet 44 is provided to function as a cooling gas G capable of cooling the motor 30. Since it includes a cooler 14, there is an advantage that a part of the refrigerant to be expanded can be used as a cooling gas G without using a separate cooling gas G.

Further, in the gas cycle heat pump 100, the cooling gas G flowing along the cooling path 14 is transferred from the turbine nozzle 47 located upstream of the turbine wheel 41 to the expansion gas passage After joining 46, since it passes through the turbine wheel 41, the cooling gas G joining the expansion gas flow EF also contributes to increasing the rotational force of the turbine wheel 41. The expansion unit 40 has the advantage of being able to do this, and the flow rate of the air flowing to the turbine wheel 41 is relatively increased by the cooling gas G joining the expansion gas flow EF. It also has the advantage of increasing performance.

In addition, in the gas cycle heat pump 100, the compressed gas passage 26 is spatially separated from the cooling passage 14, so that the gas inside the compressed gas passage 26 passes through the cooling passage 14. Since it cannot penetrate into, there is an advantage in that the motor 30 can be efficiently cooled without a pressure loss in the compression unit 20.

In the gas cycle heat pump 100, at least one air bearing 34 or 35 supporting a load in a radial direction or an axial direction of the rotation shaft 31 is provided at least one of both ends of the rotation shaft 31. Since it is mounted, the service life of the motor 30 is increased and vibration noise is reduced by the air bearings 34 and 35, and the bearings 34 and 35 are cooled by air as a refrigerant even without separate oil or coolant. It has the advantage of being easy to cool.

In addition, in the gas cycle heat pump 100, the cooling passage 14 includes passages 14a, 14b, 14c, and 14d penetrating the housing 10 so as to cool the housing 10. , There is an advantage in that the housing 10 can be quickly cooled using air, which is a gas (G) for cooling.

In addition, the gas cycle heat pump 100 includes: an inner housing 12 having the motor accommodating space 13; An outer housing 11 surrounding the inner housing 12; and the cooling passage 14 is provided between the outer surface of the inner housing 12 and the inner surface of the outer housing 11 Since the outer air passage 14a is included, it is easy to form the outer air air passage 14a, and the air flowing through the outer air passage 14a can be quickly cooled by the cooling fin 111.

In addition, the gas cycle heat pump 100 may not use a harmful refrigerant such as hydrofluorocarbon (HFC) because the gas (G) as the refrigerant contains pure air having a predetermined content or more. Bar, It has the advantage of being eco-friendly.

Meanwhile, FIG. 5 shows a gas cycle heat pump 200 as a second embodiment of the present invention. Since most of the configuration and effects of the gas cycle heat pump 200 are the same as or correspond to those of the gas cycle heat pump 100 described above, only differences between the two will be described below.

As shown in FIG. 5, the gas cycle heat pump 200 has a structure in which the turbine nozzle 47 is not communicated with the downstream air passage 14d, and further includes an outlet air passage 14e and an outlet air passage ( 14f).

As shown in FIG. 6, the outflow passage 14e has one end in communication with the rear end of the inner passage 14c and the other end in communication with the outside through the cooling gas outlet 142a.

The cooling gas outlet 142a is formed at the rear end of the outer housing 11 and communicates the motor accommodating space 13 with the outside.

As shown in FIG. 6, the outflow passage 14f has one end communicating with the inner passage 14c near the thrust bearing 35, and the other end communicating with the outside through the cooling gas outlet 142b. are connected

The cooling gas outlet 142b is formed at the rear end of the outer housing 11 and communicates the motor accommodating space 13 with the outside.

In the gas cycle heat pump 200, the cooling gas G, which cools the motor 30 and the like while circulating through the cooler 14, is sent back to the turbine wheel 41 and recycled. The gas cycle heat Unlike the pump 100, the cooling gas (G) that circulated through the cooling passage 14 is discharged to the outside of the housing 10 through the cooling gas outlets 142a and 142b. Difference in that it is not recycled there is

The use of the gas cycle heat pump 200 has a simpler structure than the gas cycle heat pump 100 . In addition, since the air pressure in the motor accommodating space 13 is low, there is an advantage in that the load acting on the air bearings 34 and 35 is relatively reduced.

However, in the case of using the gas cycle heat pump 200, since a part of the cooling gas G is discharged to the outside and discarded, the performance and efficiency of the expansion unit 40 are slightly reduced. there is.

In the above-described embodiments, it is assumed that the refrigerant gas is 100% pure air, but a case in which a certain portion of other gases is mixed with pure air is included as a matter of course.

In the above-described embodiments, the housing 10 has a double casing structure including an outer housing 11 and an inner housing 12, but a structure having only the outer housing 11 is also possible.

In the above-described embodiments, the bearings 34 and 35 are provided as air bearings, but other types of non-contact bearings such as gas bearings and magnetic bearings may be used as a matter of course.

In the above-described embodiments, a separate sealing means for confidentiality is not described, but it goes without saying that various types of sealing means may be used.

Although the present invention has been described above, the technical scope of the present invention is not limited to the contents described in the above-described embodiments, and an equivalent configuration modified or changed by a person skilled in the art is the technical scope of the present invention. It is clear that it does not go beyond the scope of ideas.

＊ Description of symbols for main parts of drawings ＊
100, 200: gas cycle heat pump
10: housing
11: outer housing
12: inner housing
13: motor accommodating space
14: with cooler
14a: external crossroads
14b: shearing machine
14c: inner girdles
14d: rear crossroads
14e: spillway
14f: spillway
20: compression unit
21: impeller
22: outer cover
23: inner cover
24: compressed gas inlet
25: compressed gas outlet
26: compressed gas flow path
30: motor
31: axis of rotation
32: stator
33: rotor
34: journal bearing
35: thrust bearing
40: expansion unit
41: turbine wheel
42: outer cover
43: inner cover
44: inflation gas inlet
45: expansion gas outlet
46: expansion gas flow path
47: turbine nozzle
111: cooling fin
141: cooling gas inlet
142, 142a, 142b: cooling gas outlet
441: expansion gas storage space
1: Compressor
2: high temperature heat exchanger
3: Inflator
4: low temperature heat exchanger
5, 6: heat source

Claims (8)

As a heat pump capable of transferring heat from one point to another,
a compressed gas inlet through which gas, which is a refrigerant to be compressed, is sucked; an impeller for compressing the gas introduced through the compressed gas inlet; a compressed gas outlet through which the gas compressed by the impeller is discharged to the outside; a compression unit having a compressed gas flow path connected from the compressed gas inlet to the compressed gas outlet;
an expansion gas inlet through which gas, which is a refrigerant to be expanded, is sucked; a turbine wheel that can be rotated by the gas introduced through the expansion gas inlet; an expansion gas outlet through which the gas passing through the turbine wheel is discharged to the outside; an expansion unit having an expansion gas flow path connected from the expansion gas inlet to the expansion gas outlet;
a motor having a rotational shaft having one end coupled non-rotatably with the impeller and the other end non-rotatably coupled with the turbine wheel;
a housing having a motor accommodating space accommodating the motor;
A cooler provided to pass through the motor accommodating space and provided so that a part of the gas introduced through the expansion gas inlet can function as a cooling gas capable of cooling the motor; gas characterized by comprising a cycle heat pump According to claim 1,
The gas for cooling flowing along the cooling passage passes through the turbine wheel after joining the expansion gas passage upstream of the turbine wheel. According to claim 1,
The cooling gas flowing along the cooling passage is discharged to the outside of the housing through a cooling gas outlet formed in the motor accommodating space. According to claim 1,
The compressed gas passage is spatially separated from the cooling passage, so that the gas inside the compressed gas passage cannot penetrate into the cooling passage. According to claim 1,
At least one non-contact bearing supporting a radial load or an axial load of the rotation shaft is mounted on at least one of both ends of the rotation shaft. According to claim 1,
The cooling passage includes a passage penetrating the housing so as to cool the housing. According to claim 1,
The housing may include an inner housing having a space for accommodating the motor; An outer housing surrounding the inner housing;
The cooling air passage includes a air passage provided between an outer surface of the inner housing and an inner surface of the outer housing. According to claim 1,
The gas as the refrigerant is a gas cycle heat pump, characterized in that it contains more than a predetermined content of air

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