JP7237231B1 - Compressors and air conditioners - Google Patents

Abstract

An object of the present invention is to provide a compressor and an air conditioner that can prevent foreign matter from circulating in the compressor and improve the reliability of the compressor.
SOLUTION: The compressor includes an electric motor having a rotor 51 containing a magnet 52, a rotary shaft 42 rotated by the rotor 51, and a compression mechanism for compressing fluid sucked by the rotation of the rotary shaft 42. The rotating shaft 42 has a through hole 60 passing through the rotating shaft 42 in its axial direction. The rotor 51 has a communicating passage 54 that continues to the through hole 60 and extends radially about the rotating shaft 42, and a collecting space 55 that is provided on the outer periphery of the communicating passage 54 and has at least one surface magnetized by a magnet. and
[Selection drawing] Fig. 4

Description

The present invention relates to a compressor and an air conditioner equipped with the compressor.

Some compressors are equipped with a rotating shaft and have a through hole in the rotating shaft to supply lubricating oil to each sliding part and to release the bubbly gas generated in the lower part of the compressor to the upper part of the compressor. . Compressors with through-holes in the rotating shaft can prevent oil from running out of the sliding parts because bubbled gas is carried to the top of the compressor. At the same time, foreign matter is also easily carried to the upper part of the compressor.

Foreign matter includes dust, abrasion powder, welding balls (spatter), and the like. Among these foreign matter, abrasion powder and welding balls are particularly hard and magnetic, and therefore there is concern about abrasive wear (scratching wear) and short-circuiting of motor coils due to foreign matter getting caught in the sliding portion. For this reason, it is important to collect iron-based contaminants, such as abrasion powder and welding balls, which are hard and magnetic.

Conventionally, a cylindrical portion is provided at the end of the drive shaft so that the interior is connected to the shaft passage, and foreign matter contained in the refrigerant gas is separated by the action of centrifugal force, and a foreign matter capturing member provided in the cylindrical portion separates the foreign matter. A compressor that captures separated foreign matter is known (see Patent Document 1, for example).

JP 2015-148202 A

However, since the conventional compressor separates foreign matter by the action of centrifugal force, when the centrifugal force does not work strongly, such as when the compressor is stopped or when operation is started, the trapped foreign matter returns to the oil and is re-introduced. There was a concern that the oil would circulate inside the compressor together with the oil, and there was a problem that the reliability of the compressor would decrease.

In view of the above problems, the present invention provides an electric motor including a rotor containing magnets;
a rotating shaft rotated by a rotor;
A compression mechanism that compresses the fluid sucked by the rotation of the rotating shaft,
the rotating shaft has a through-hole passing through in the axial direction of the rotating shaft;
Compression, wherein the rotor has a communication passage that is continuous with the through hole and extends radially about the rotation axis, and a collection space that is provided in the outer peripheral portion of the communication passage and has at least one surface magnetized by a magnet. machine is provided.

ADVANTAGE OF THE INVENTION According to this invention, it can prevent a foreign material from circulating through the inside of a compressor, and can improve the reliability of a compressor.

The figure which showed the structural example of an air conditioner. The figure explaining the refrigerant circuit of an air conditioner. The figure which showed the structural example of a compressor. FIG. 2 is a cross-sectional view showing a first configuration example of a rotor fixed to a rotating shaft; The figure explaining arrangement|positioning of the magnet incorporated in the rotor. FIG. 5 is a perspective view of the rotor shown in FIG. 4; FIG. 5 is a cross-sectional view showing a second configuration example of the rotor fixed to the rotating shaft; FIG. 5 is a cross-sectional view showing a third configuration example of the rotor fixed to the rotating shaft; FIG. 11 is a cross-sectional view showing a fourth configuration example of the rotor fixed to the rotating shaft;

FIG. 1 is a diagram showing a configuration example of an air conditioner. The air conditioner 10 includes at least one indoor unit 11 installed in a space (indoor) to be air-conditioned, and at least one outdoor unit 12 installed outdoors. The air conditioner 10 performs air conditioning by circulating the refrigerant between the indoor unit 11 and the outdoor unit 12 and exchanging heat between the indoor air and the refrigerant. Therefore, the indoor unit 11 and the outdoor unit 12 are connected by refrigerant pipes 13 and 14 for circulating the refrigerant.

A hydrofluorocarbon (HFC), a hydrofluoroolefin (HFO), or the like can be used as the refrigerant. Types of HFC include R-410A, R-32, R-134a and the like, and types of HFO include R-1234yf and the like. Since these refrigerants do not contain chlorine atoms, they have a certain deterrent effect on ozone depletion.

The indoor unit 11 receives an operation command, a temperature setting change, an operation stop command, etc. from a remote controller 15 placed indoors through wireless communication using infrared rays or the like. The indoor unit 11 receives an operation command from the remote controller 15 and starts up, and instructs the outdoor unit 12 to start up. After the outdoor unit 12 is started, the outdoor unit 12 controls a compressor, an expansion valve, and the like included in the outdoor unit 12 so that the indoor temperature reaches the set temperature, and adjusts the circulation amount of the refrigerant, and the like.

The indoor unit 11 instructs the outdoor unit 12 to change the set temperature and stop the operation when receiving the command to change the set temperature and to stop the operation. After instructing the outdoor unit 12 to stop operation, the indoor unit 11 stops operating itself. When the outdoor unit 12 receives an instruction to change the set temperature, the outdoor unit 12 changes the set temperature and controls the compressor, the expansion valve, and the like so as to achieve the changed set temperature. When the outdoor unit 12 receives an operation stop instruction, it stops the compressor and stops its own operation.

FIG. 2 is a diagram for explaining the configurations of the indoor unit 11 and the outdoor unit 12 that constitute the air conditioner 10 and the refrigerant circuit. The air conditioner 10 has multiple operation modes such as a cooling mode and a heating mode. The arrows shown in FIG. 2 indicate the direction in which the refrigerant flows in the cooling mode, and the cooling operation in the cooling mode will be mainly described here. Note that the arrows are reversed in the heating mode.

The indoor unit 11 includes an indoor heat exchanger 20 and an indoor fan 21 . The indoor fan 21 is driven by an indoor fan drive motor, takes in indoor air, and sends it to the indoor heat exchanger 20 . The indoor heat exchanger 20 has a plurality of heat transfer tubes through which a refrigerant flows, and is configured such that the air sent by the indoor fan 21 comes into contact with the outer surfaces of the plurality of heat transfer tubes to exchange heat. . The air heat-exchanged by the indoor heat exchanger 20 is discharged indoors.

The indoor unit 11 can also include various sensors for measuring indoor temperature, indoor humidity, etc., and an indoor expansion valve for adjusting the amount of refrigerant supplied to the indoor unit 11, and the like.

The outdoor unit 12 includes a compressor 30 , a four-way valve 31 , an outdoor expansion valve 32 , an outdoor heat exchanger 33 and an outdoor fan 34 . The compressor 30 is driven by a compressor drive motor, compresses low-pressure gas refrigerant, and discharges it as high-pressure gas refrigerant. The compressor 30 is connected to an accumulator 35 that stores refrigerant to be supplied to the compression mechanism. The accumulator 35 also has the function of preventing the liquid from returning to the compression mechanism and adjusting the dryness of the refrigerant to an appropriate degree. The dryness is the proportion of steam in wet steam that indicates the mixed state of steam and microdroplets.

The four-way valve 31 is a valve that switches the direction of refrigerant flow according to the operation mode of the air conditioner 10 . The outdoor expansion valve 32 is a valve that reduces the pressure of the high-pressure refrigerant to expand it and controls the flow rate of the refrigerant. The outdoor fan 34 is driven by an outdoor fan drive motor, takes in outdoor air, and sends it to the outdoor heat exchanger 33 . Like the indoor heat exchanger 20, the outdoor heat exchanger 33 has a plurality of heat transfer tubes through which a refrigerant flows, and the air taken in by the outdoor fan 34 contacts the outer surfaces of the plurality of heat transfer tubes to exchange heat. is configured to do The air heat-exchanged by the outdoor heat exchanger 33 is discharged outdoors.

The outdoor unit 12 has a control device 36 . The control device 36 controls the compressor 30 , the four-way valve 31 , the outdoor expansion valve 32 , the outdoor fan 34 and the indoor fan 21 . Specifically, the control device 36 controls the rotational speed of each motor that drives the compressor 30, the outdoor fan 34, and the indoor fan 21, the opening degree of the outdoor expansion valve 32, switching of the four-way valve 31, and the like. The outdoor unit 12 can be provided with various sensors such as a temperature sensor for detecting discharge temperature and the like in order to control the compressor 30 and the like. The control device 36 performs each of the above controls based on information detected by various sensors provided in the indoor unit 11 and the outdoor unit 12 .

When performing cooling operation in the cooling mode, the indoor heat exchanger 20 functions as an evaporator, and the outdoor heat exchanger 33 functions as a condenser. For this reason, the controller 36 controls the compressor 30, the outdoor heat exchanger 33, the outdoor expansion valve 32, the indoor heat exchanger 20, the four-way valve 31, the accumulator 35, and the compressor 30 in this order, as indicated by the arrows. to circulate the refrigerant enclosed in the

The compressor 30 compresses a low-temperature, low-pressure gaseous refrigerant and discharges it as a high-temperature, high-pressure refrigerant gas. The outdoor heat exchanger 33 heat-exchanges the refrigerant gas discharged from the compressor 30 with outdoor air to cool and condense the refrigerant gas. The outdoor expansion valve 32 reduces the pressure of the condensed refrigerant to partially vaporize it. Therefore, the refrigerant is supplied to the indoor units 11 in a state in which gas and liquid are mixed. The degree of opening of the outdoor expansion valve 32 is adjusted by the control device 36 so that an appropriate amount of liquid is obtained.

The indoor heat exchanger 20 heat-exchanges the refrigerant supplied to the indoor unit 11 with indoor air, and evaporates all the refrigerant. The refrigerant leaving the indoor heat exchanger 20 is a low-temperature, low-pressure gaseous refrigerant, which is sent to the accumulator 35 via the four-way valve 31 and returned to the compressor 30 .

The control device 36 is not limited to being mounted on the outdoor unit 12 . Therefore, the control device 36 may be mounted on the indoor unit 11, or may be mounted on another central control panel or the like. Also, the control device 36 may be divided into two devices and mounted in each of the indoor unit 11 and the outdoor unit 12 .

FIG. 3 is a diagram showing a configuration example of the compressor 30. As shown in FIG. The compressor 30 is a rotary compressor, and includes an electric motor 40, a compression mechanism 41, a rotary shaft 42 connecting the electric motor 40 and the compression mechanism 41, and a sealed container 43 housing the electric motor 40, the compression mechanism 41, and the rotary shaft 42. including. As shown in FIG. 3, in the case of vertical installation with the longitudinal direction of the sealed container 43 facing the vertical direction, the electric motor 40 is arranged on the upper side and the compression mechanism 41 is arranged on the lower side.

Electric motor 40 includes a stator 50 and a rotor 51 . The stator 50 surrounds the rotor 51 and is fixed to the inner surface of the closed container 43 . The stator 50 has a coil, and a cord for supplying current is connected to the coil. The rotor 51 incorporates magnets such as permanent magnets, and is rotated in a certain direction by a magnetic field generated by current flowing through the coils of the stator 50 .

The rotor 51 has a hole with a predetermined diameter formed in the center so that the rotary shaft 42 can be inserted and attached. Therefore, the rotor 51 is fixed so as to surround the upper end side of the rotating shaft 42 . The rotating shaft 42 has an eccentric portion for eccentrically rotating a roller, which is a cylindrical rotating body, on an outer peripheral portion at a predetermined position in the axial direction, which is the longitudinal direction of the rotating shaft 42 . In addition, the rotating shaft 42 is provided with a through hole 60 so as to pass through the inside from the upper end, which is one end in the axial direction, to the lower end, which is the other end in the axial direction.

The rotating shaft 42 pumps up lubricating oil (oil) stored below the compression mechanism 41 at the bottom of the sealed container 43 in the through hole 60 on the lower end side, and slides between the cylinder and the roller. It has a paddle 61 and an oil supply piece 62 for supplying oil to the moving parts. The oil has high lubricating properties, reduces wear of each sliding part, and is supplied for sealing so that the refrigerant, which is the fluid compressed in the compression mechanism 41, does not leak out of the gap.

Since the oil is discharged from the compression mechanism 41 together with the refrigerant, it must be returned to the bottom of the sealed container 43 where it is stored, and has the property of being dissolved in the refrigerant (refrigerant compatibility) to some extent. The oil is discharged together with the refrigerant into the space above the compression mechanism 41 below the electric motor 40 . It flows downwards, passes through a discharge hole provided at the edge of the compression mechanism 41 and is returned to the bottom of the closed container 43 .

In the example shown in FIG. 3, the compression mechanism 41 is provided in two stages and includes two cylinders 70 and 71, a partition plate 72 separating the two cylinders 70 and 71, a main bearing 73, and a sub-bearing 74. . The upper stage of the two stages constitutes one compression chamber with the cylinder 70, the main bearing 73 and the partition plate 72, and the lower stage constitutes one compression chamber with the cylinder 71, the sub-bearing 74 and the partition plate 72. Configure the compression chamber. The main bearing 73 is fixed to the inner surface of the sealed container 43 and rotatably supports the rotating shaft 42 . Each cylinder 70, 71 has a roller into which each of the two eccentrics provided on the rotary shaft 42 is inserted, and has a vane that abuts the roller and separates the compression chamber into two spaces. The vanes are provided with springs and configured to maintain contact with the rollers.

Cylinders 70 and 71 have a refrigerant suction port and a refrigerant discharge port on both sides of the vane. The refrigerant sucked from the suction port is compressed by rollers rotating inside the cylinders 70 and 71 while being in contact with the inner surfaces of the cylinders 70 and 71, and is discharged from the discharge port.

The sliding parts to which oil is supplied are between the cylinders 70, 71 and the rollers, between the cylinders 70, 71 and the vanes, between the rotating shaft 42 and the main bearing 73, and between the rotating shaft 42 and the sub-bearing 74. Between and so on. Therefore, the oil supplied to these sliding portions is mixed with the refrigerant in the compression chamber and discharged together with the refrigerant.

The oil returned to the bottom of the sealed container 43 contains refrigerant. When the compressor 30 stops and the temperature of the oil drops, the refrigerant in the oil condenses. When the compressor 30 is restarted and the temperature of the oil rises, the refrigerant in the oil evaporates to generate foamy gas. When the bubble gas is generated, the oil supplied to each sliding portion contains the bubble gas, and the sliding portion runs out of oil.

However, since the rotating shaft 42 is provided with the through hole 60 , the generated bubble-like gas can be discharged through the through hole 60 . Therefore, it is possible to suppress the oil level shortage of each sliding portion. The oil contains abrasion powder generated by sliding of metal parts in each sliding portion and weld balls generated during welding. Since these materials have high hardness and are magnetic materials, there are concerns about abrasive wear due to foreign matter being caught in each sliding portion and short-circuiting of electric motor coils (motor coils).

Foreign matter such as abrasion powder and weld balls is carried to the upper part of the compressor through the through holes 60 together with oil and foamy gas. That is, foreign matter is carried to the upper portion of electric motor 40 . If the foreign matter carried to the upper part of the electric motor 40 returns to the oil and circulates inside the compressor together with the oil, the concerns about the above-mentioned abrasive wear and short-circuiting of the motor coil cannot be resolved.

Therefore, it is possible to provide a mechanism for collecting foreign matter carried to the upper part of the electric motor 40, especially iron-based foreign matter, which is a hard magnetic material, so that the foreign matter does not return to the oil. An example of a specific configuration is shown in FIG. FIG. 4 is a cross-sectional view showing a first configuration example of the rotor 51 fixed to the rotating shaft 42 indicated by a rectangle A in FIG.

The rotor 51 has a hole in the center into which the rotating shaft 42 can be inserted, into which the upper end of the rotating shaft 42 is inserted and fixed to the rotating shaft 42 . A cross section obtained by cutting the rotor 51 fixed to the rotating shaft 42 in the axial direction has a shape in which the rotors 51 are arranged on both sides of the rotating shaft 42 . The rotor 51 incorporates magnets 52 such as permanent magnets so as to extend in the axial direction.

FIG. 5 is a diagram showing an arrangement example of the magnets 52 inside the rotor 51. As shown in FIG. The magnets 52 each have a rectangular cross-section and have a plate-like shape elongated in the axial direction. be done. Here, four magnets 52 are arranged so as to surround the rotation shaft 42, but the number of magnets 52 is not limited to this, and three or five or more may be arranged.

Referring to FIG. 4 again, the upper end of rotating shaft 42 is inserted to a position not exceeding the upper end of hole 53 in the center of rotor 51 . In the example shown in FIG. 4, the upper end of the rotating shaft 42 is inserted to a position lower than the upper end of the central hole 53 of the rotor. The upper surface of the rotor 51 continues to the through hole 60 of the rotary shaft 42 inserted into the central hole 53, and extends radially around the rotary shaft 42 in all directions. A collection space 55 provided as a collection groove in the outer peripheral portion is provided.

An outer peripheral wall 56 is provided on the outer peripheral portion of the collection space 55 . The upper surface of the outer peripheral wall 56 is positioned higher than the communication path 54 . A circular upper end plate 57 is provided on the upper surface of the outer peripheral wall 56 so as to cover the upper surface of the rotor 51 . By providing the upper end plate 57, it is possible to suppress blowing up of foreign matter. A discharge hole 58 is provided in the center of the upper end plate 57 .

The gas component (mainly refrigerant) in the bubble-like gas carried through the through hole 60 is sent to the upper part of the compressor through the discharge hole 58 provided in the upper end plate 57 and is sent to the upper part of the closed container 43 . It is discharged from the outlet. Foreign matter contained in the bubble-like gas coming out of the through hole 60 is radially sent to the collection space 55 through the communicating passage 54 by the centrifugal force of the rotating rotor 51 together with the oil carried through the through hole 60 .

The collection space 55 collects foreign matter sent through the communication path 54 . Foreign matter remains in the collection space 55 while the centrifugal force is acting.

However, when the centrifugal force does not act strongly, such as when the compressor 30 is stopped or when the operation is started, there is a concern that the once-collected foreign matter may return to the oil and circulate inside the compressor together with the oil again.

Therefore, at least one surface of the collection space 55 is magnetized by the magnet 52 built into the rotor 51 . The foreign matter is an iron-based foreign matter that is a magnetic material, and by magnetizing at least one surface of the collection space 55, the foreign matter continues to be attracted to the at least one magnetized surface. Therefore, even when the centrifugal force does not act strongly, such as when the compressor 30 is stopped or when the compressor 30 is started, the collected foreign matter does not return to the oil.

6 is a perspective view of the rotor 51 shown in FIG. 4. FIG. The collection space 55 is separated from the magnets 52 built in the rotor 51 by a predetermined distance, and is provided at a position where the bottom surface of the collection space 55 and the top surface of the magnets 52 face each other. Thereby, the bottom surface of the collection space 55 can be magnetized.

The collection space 55 may be magnetized on any face of the collection space and magnets 52 contained in the rotor 51 may be used for the magnetization of that face. Therefore, there is no need to separately provide a magnet to magnetize at least one surface of the collecting space.

The foreign matter collected in the collection space 55 is attracted to and collected by the magnetized surface of the collection space 55, and even when the compressor 30 is stopped, the foreign matter is kept in the collection space 55. It's becoming

As shown in FIGS. 4 and 6, the rotor 51 is formed such that the communication passages 54 extend in all directions in the radial direction B with the through hole 60 as the center. The height is up to the plate 57, which is smaller than the height from the bottom of the collecting space 55 to the upper end plate 57 covering the upper part.

FIG. 7 is a cross-sectional view showing a second configuration example of the rotor 51 fixed to the rotating shaft 42. As shown in FIG. In the example shown in FIG. 7 , the diameter D1 of the discharge hole 58 provided in the upper end plate 57 is smaller than the diameter D2 of the through hole 60 provided in the rotating shaft 42 . As a result, the foreign matter carried through the through hole 60 is prevented from directly escaping to the upper portion of the rotor 51, and the foreign matter collection effect due to the centrifugal force can be improved.

FIG. 8 is a cross-sectional view showing a third configuration example of the rotor 51 fixed to the rotating shaft 42. As shown in FIG. In the examples shown in FIGS. 4 and 7, the number of discharge holes 58 provided in the upper end plate 57 is one and is provided on the same line as the through hole 60 provided in the rotating shaft 42. However, the example shown in FIG. Now, the discharge hole 58 provided in the upper end plate 57 is above the communication path 54 . That is, the discharge hole 58 is provided at a position between the through hole 60 and the collection space 55 .

In this way, by providing the discharge hole 58 provided in the upper end plate 57 at a position between the through hole 60 and the collection space 55, there is no part of the rotating shaft 42 that directly escapes from the through hole 60, so that the flow It is possible to prevent foreign matter from blowing up due to the force of the air.

FIG. 9 is a cross-sectional view showing a fourth configuration example of the rotor 51 fixed to the rotating shaft 42. As shown in FIG. A detachable collecting component 80 for collecting foreign matter is attached to the upper surface of the rotor 51 . The collecting component 80 includes a communicating portion 81 that is continuous with the through hole 60 and a collecting space 82 arranged on the outer peripheral side of the communicating portion 81 and above the magnets 52 built into the rotor 51 . In the example shown in FIG. 9, the communicating portion 81 is located in the center hole of the rotor 51 and widens toward the upper end of the rotating shaft 42 below, and the collection space 82 extends above the upper end of the rotor 51. It is supposed to be a bag-shaped thing to be installed. The upper end of the rotor 51 with which the collection space 82 is in contact is magnetized by a magnet 52 so as to attract ferrous foreign matter.

Even if a collection space cannot be created at the upper end of the rotor 51, foreign matter can be collected by attaching a collection component 80 as shown in FIG.

Although the compressor and the air conditioner of the present invention have been described in detail with the above-described embodiments, the present invention is not limited to the above-described embodiments, and other embodiments, additions, modifications, It can be changed within the range that a person skilled in the art can conceive, such as deletion, and as long as the action and effect of the present invention are exhibited in any aspect, it is included in the scope of the present invention.

DESCRIPTION OF SYMBOLS 10... Air conditioner 11... Indoor unit 12... Outdoor unit 13, 14... Refrigerant piping 15... Remote controller 20... Indoor heat exchanger 21... Indoor fan 30... Compressor 31... Four-way valve 32... Outdoor expansion valve 33... Outdoor heat Exchanger 34 Outdoor fan 35 Compressor body 36 Accumulator 37 Control device 40 Electric motor 41 Compression mechanism 42 Rotating shaft 43 Closed container 50 Stator 51 Rotor 52 Magnet 53 Hole 54 Communication path 55 Collection space 56 Peripheral wall 57 Upper end plate 58 Discharge hole 60 Through hole 61 Paddle 62 Oil supply pieces 70, 71 Cylinder 72 Partition plate 73 Main bearing 74 Sub-bearing 80 Collection part 81 ... Communicating part 82 ... Collection space

Claims (7)

an electric motor having a rotor containing magnets;
a rotating shaft rotated by the rotor;
a compression mechanism for compressing the fluid sucked by the rotation of the rotating shaft;
the rotating shaft has a through-hole passing through in the axial direction of the rotating shaft;
The rotor includes a communicating passage extending radially about the rotating shaft and continuing to the through hole, and a collection space provided in an outer peripheral portion of the communicating passage and having at least one surface magnetized by the magnet. and a compressor. The rotor includes an upper end plate that covers the upper part of the rotating shaft, the communication passage, and the collection space when the rotating shaft is installed with the axial direction of the rotating shaft in the vertical direction,
2. The compression according to claim 1, wherein among the upper end of the rotating shaft, the communicating path surface of the communicating path, and the bottom surface of the collecting space, the flow path height from the communicating path surface of the communicating path to the upper end plate is the smallest. machine. 3. The compressor of claim 2, wherein said top plate has at least one discharge hole. 4. The compressor according to claim 3, wherein the diameter of the discharge hole provided in the upper end plate is smaller than the diameter of the through hole. 4. The compressor according to claim 3, wherein said discharge hole is provided on said communication path between said radial through-hole and said collection space. an electric motor having a rotor containing magnets;
a rotating shaft rotated by the rotor;
a compression mechanism for compressing the fluid sucked by the rotation of the rotating shaft;
and a collecting component mounted on the rotor when the axial direction of the rotating shaft is oriented in the vertical direction,
the rotating shaft has a through-hole passing through in the axial direction of the rotating shaft;
The collection component is provided with a communicating portion that is continuous with the through hole and extends radially about the rotating shaft and toward the rotor, and is provided on an outer peripheral side of the communicating portion, and is arranged to generate at least one and a collection space with magnetized faces. An air conditioner, comprising the compressor according to any one of claims 1 to 6, wherein air conditioning is performed by exchanging heat between a fluid circulated by the compressor and air in a space.

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