JP2019066130A - Refrigeration cycle device - Google Patents

Abstract

To provide a refrigeration cycle device that can discharge accumulated water in a compressor to the outside of the compressor.SOLUTION: A refrigeration cycle device 1 according to an embodiment comprises an evaporator 2, a compressor 3, a condenser 4, an atomizing mechanism 5, and a refrigerant supply passage 11. The compressor 3 is connected to the evaporator 2 by a suction pipe 6 and connected to the condenser 4 by a discharge pipe 8. The discharge pipe 8 is connected to a discharge port of the compressor 3 and an inlet of the condenser 4. The condenser 4 is connected to the evaporator 2 by a return path 9. A drain circuit 7 connects a flow passage wall surface 3b of a refrigerant vapor path inside the compressor 3 and the inside of the evaporator 2 or the condenser 4.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a refrigeration cycle apparatus.

  As a conventional refrigeration cycle apparatus, a refrigeration cycle comprising a two-stage compressor, wherein refrigerant vapor discharged from the first-stage compressor is cooled before being sucked into the second-stage compressor The device is known.

  As shown in FIG. 7, the air conditioner 500 described in Patent Document 1 includes an evaporator 510, a centrifugal compressor 531, a roots compressor 532, a steam cooler 533, and a condenser 520. A centrifugal compressor 531 is provided at the front stage, and a Roots-type compressor 532 is provided at the downstream stage. The evaporator 510 generates refrigerant vapor in a saturated state. The refrigerant vapor is sucked into the centrifugal compressor 531 and compressed. The refrigerant vapor compressed by the centrifugal compressor 531 is further compressed by the roots compressor 532. In the steam cooler 533 disposed between the centrifugal compressor 531 and the roots compressor 532, the refrigerant steam is cooled.

  The steam cooler 533 is provided between the centrifugal compressor 531 and the roots compressor 532. In the steam cooler 533, water is directly sprayed to the refrigerant steam. Alternatively, in the vapor cooler 533, heat exchange is indirectly performed between the cooling medium such as air and the refrigerant vapor.

  In order to improve the efficiency of the air conditioner 500, the degree of superheat of the refrigerant to be drawn into the roots compressor 532 may be reduced in the steam cooler 533. However, the degree of superheat generated in the compression process of the centrifugal compressor 531 and the degree of superheat generated in the compression process of the roots compressor 532 can not be removed.

  On the other hand, as means for removing the degree of superheat generated in the compression process of a centrifugal compressor, an apparatus equipped with an atomization mechanism for spraying droplets having evaporation such as water toward the suction port of the centrifugal compressor is known. . The superheat degree generated in the compression process of the centrifugal compressor 531 can be removed by the action of the cooling effect by the latent heat of vaporization of the droplets, and the efficiency of the air conditioning apparatus 500 can be improved.

JP, 2008-122012, A

  However, among the droplets, particles of large particle size adhere to the wall surface of the refrigerant vapor path of the centrifugal compressor without evaporation and have a problem of staying. Since the flow passage wall surface of the centrifugal compressor is at a temperature equal to or higher than the saturated vapor temperature of the compressed refrigerant, the stagnant liquid phase refrigerant receives heat from the flow passage wall and evaporates, and the suction flow rate increases. Compression theoretical power is increased.

  The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a refrigeration cycle apparatus capable of discharging the staying liquid to the outside of the compressor.

In order to solve the conventional problems, the present disclosure is
A velocity type compressor installed above the evaporator, which is connected to the evaporator directly or using a suction pipe, and sucks and compresses gas phase refrigerant generated by the evaporator;
A condenser which is disposed below the compressor and condenses the gas-phase refrigerant compressed by the compressor to generate a liquid-phase refrigerant;
It is disposed on the steam path from the inlet of the suction pipe to the discharge port of the compressor, and sprays the liquid phase refrigerant toward the steam path, or is disposed inside the evaporator and liquid toward the suction port of the compressor Atomization mechanism that sprays a two-phase refrigerant,
A flow passage wall surface of a refrigerant vapor path between the downstream side of the atomization mechanism and the discharge portion of the compressor;
A drain circuit connecting an evaporator or a condenser;
To provide a refrigeration cycle apparatus.

  Thereby, the refrigerant liquid adhering to the refrigerant vapor path wall surface inside the compressor can be discharged to the outside of the compressor before it evaporates.

  According to the present disclosure, the refrigerant liquid does not stay in the refrigerant vapor path inside the compressor. As a result, the evaporation of the stagnant liquid refrigerant is suppressed, and the suction flow rate of the downstream stage is reduced, whereby the theoretical compression power is reduced, and the efficiency of the refrigeration cycle apparatus is improved.

The block diagram of the refrigerating-cycle apparatus concerning Embodiment 1 or Embodiment 3 of this indication Cross section of an example of the atomization mechanism Sectional view of the compressor of the refrigeration cycle apparatus shown in FIG. The block diagram of the refrigerating-cycle apparatus concerning Embodiment 2 of this indication Sectional view of the compressor of the refrigeration cycle apparatus shown in FIG. Sectional drawing of the compressor of the refrigerating-cycle apparatus concerning Embodiment 3 of this indication Configuration diagram of the conventional air conditioner shown in Patent Document 1

  According to the air conditioner described in Patent Document 1, in the steam cooler 533, the degree of superheat of the refrigerant drawn into the roots compressor 532 can be reduced. However, the degree of superheat generated in the compression process of the centrifugal compressor 531 and the degree of superheat generated in the compression process of the roots compressor 532 can not be removed. As the degree of superheat of the refrigerant increases, the enthalpy of the refrigerant also increases.

  The ideal compression process in a compressor is along a fully adiabatic isentropic line. In the refrigerant ph diagram, as the refrigerant's enthalpy increases, the slope of the isentropic line becomes gentler, and a larger compression power is required. As the degree of superheat of the refrigerant increases, more compression power is required to raise the pressure of the unit mass refrigerant to a predetermined pressure. In other words, the load on the compressor increases and the power consumption of the compressor increases.

  The atomized liquid-phase refrigerant generated by the atomization mechanism is sucked into the compressor. When the misty liquid phase refrigerant is sucked into the compressor, heat exchange occurs between the gas phase refrigerant whose temperature is raised by the compressor and the temperature rises, and the misty liquid phase refrigerant, and the gas phase refrigerant in the superheated state Is continuously cooled by the evaporation of the misty liquid phase refrigerant. Thereby, the increase in enthalpy of the refrigerant resulting from the increase in the degree of superheat of the refrigerant in the compression process is continuously suppressed. The compression power required by the compressor can be reduced to less than that required for fully adiabatic isentropic compression. The work to be done by the compressor to raise the pressure of the refrigerant to a predetermined pressure can be significantly reduced.

A refrigeration cycle apparatus according to a first aspect of the present disclosure is
An evaporator that evaporates a liquid phase refrigerant to generate a gas phase refrigerant;
A velocity type compressor installed above the evaporator, which is connected to the evaporator directly or using a suction pipe, and sucks and compresses gas phase refrigerant generated by the evaporator;
A condenser which is disposed below the compressor and condenses the gas-phase refrigerant compressed by the compressor to generate a liquid-phase refrigerant;
It is disposed on the steam path from the inlet of the suction pipe to the discharge port of the compressor, and sprays the liquid phase refrigerant toward the steam path, or is disposed inside the evaporator and liquid toward the suction port of the compressor Atomization mechanism that sprays a two-phase refrigerant,
From the flow path wall surface of the refrigerant vapor path between the downstream of the atomization mechanism and the discharge part of the compressor,
A drain circuit connected to the inside of the evaporator or condenser;
Is provided.

  According to the first aspect, among the liquid phase refrigerant sprayed in the compressor, the one with the larger particle diameter adheres to the flow path wall surface of the compressor without evaporation and the stagnant liquid is produced even though the stagnant liquid is generated. Or it is discharged to the condenser. As a result, the refrigerant liquid does not stay in the refrigerant vapor path inside the compressor. Therefore, it is possible to suppress the increase in theoretical compression power of the downstream stage impeller due to the evaporation of the stagnant liquid, suppress the power consumption of the compressor, and improve the efficiency of the refrigeration cycle apparatus.

In the second aspect of the present disclosure,
The compressor has a first impeller for providing a rotational speed to refrigerant vapor generated by the evaporator,
A first diffuser that decelerates the refrigerant vapor discharged from the first impeller and raises the pressure of the refrigerant vapor;
A return channel for receiving refrigerant vapor discharged from the first diffuser and redirecting the outward flow inward;
A second impeller that provides rotational speed to the refrigerant vapor that has passed through the return channel;
Equipped with
The drain circuit connects the inside of the condenser and the flow path wall surface of the return channel.

  The temperature of the liquid staying in the return channel rises to near the saturated vapor temperature according to the pressure boosted by the compression height of the upstream stage of the return channel, and is higher than the vapor temperature inside the evaporator. If the stagnant liquid is discharged to the evaporator, heat loss occurs. That is, since the compressor sucks in the flush vapor of the stagnant liquid which does not contribute to the refrigeration capacity of the evaporator, the theoretical compression power is increased wastefully. According to the second aspect, a high pressure ratio is required, and even when a multistage compressor is used, since the staying liquid present in the high temperature return channel is discharged to the condenser, the refrigerant liquid remains in the return channel. do not do. Furthermore, it is possible to avoid the heat loss that occurs when discharging the staying liquid to the evaporator, and to improve the efficiency of the refrigeration cycle apparatus.

In the third aspect of the present disclosure,
The compressor has a first impeller for providing a rotational speed to refrigerant vapor generated by the evaporator,
An inlet channel for introducing refrigerant vapor into the impeller;
Equipped with
The drain circuit is connected from the inside of the evaporator to a location adjacent to the inlet surface of the impeller in the channel wall surface of the inlet channel.

  The stagnant water present in the inlet channel of the first stage of the compressor has the saturated vapor pressure and the saturated vapor temperature of the evaporator. When the staying water is discharged to the condenser, the low temperature staying water mixes with the water in the high temperature condenser to generate heat loss. The liquid phase water discharged to the condenser is finally returned from the condenser to the evaporator to complete the refrigeration cycle. At that time, the liquid phase water is flash evaporated and cooled in the low pressure space of the evaporator, but the cold energy does not contribute to the refrigeration capacity of the evaporator and consumes the compression power of the compressor, so the efficiency of the refrigeration cycle apparatus Decreases. According to the third embodiment, even under a large amount of spray from the atomization mechanism under overload conditions, stagnant water is discharged to the evaporator from a location adjacent to the inlet surface of the impeller in the inlet channel wall surface, and compression is performed. The refrigerant liquid does not stay in the inlet channel of the first stage of the machine. Furthermore, the increase in the theoretical power of the compressor is suppressed as compared with the case where the refrigerant liquid is discharged to the condenser, and the efficiency of the refrigeration cycle apparatus can be improved.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 4. The present invention is not limited to the following embodiments.

Embodiment 1
As shown in FIG. 1, the refrigeration cycle apparatus 1 of the present embodiment includes an evaporator 2, a compressor 3, a condenser 4, an atomization mechanism 5, and a refrigerant supply passage 11. The compressor 3 is connected to the evaporator 2 by a suction pipe 6 and is connected to the condenser 4 by a discharge pipe 8. In detail, a suction pipe 6 is connected to the outlet of the evaporator 2 and the suction port of the compressor 3. A discharge pipe 8 is connected to the discharge port of the compressor 3 and the inlet of the condenser 4. The condenser 4 is connected to the evaporator 2 by a return path 9. The return path 9 is formed by at least one pipe. The evaporator 2, the compressor 3 and the condenser 4 are annularly connected in this order to form a refrigerant circuit 10.

  The refrigerant is evaporated in the evaporator 2 to generate a gas phase refrigerant (refrigerant vapor). The gas phase refrigerant produced by the evaporator 2 is drawn into the compressor 3 through the suction pipe 6 and compressed. The compressed gas phase refrigerant is supplied to the condenser 4 through the discharge pipe 8. The gas phase refrigerant is cooled in the condenser 4 to generate a liquid phase refrigerant (refrigerant liquid). The liquid phase refrigerant is sent from the condenser 4 to the evaporator 2 through the return path 9.

  The refrigeration cycle apparatus 1 is filled with a single type of refrigerant. As the refrigerant, fluorocarbon refrigerant, low GWP (Global Warming Potential) refrigerant and natural refrigerant can be used. Examples of fluorocarbon refrigerants include HCFC (hydrochlorofluorocarbon) and HFC (hydrofluorocarbon). HFO-1234yf etc. are mentioned as a low GWP refrigerant | coolant. Examples of natural refrigerants include CO 2 and water.

  The refrigeration cycle apparatus 1 desirably contains, as a main component, a substance whose saturated vapor pressure at normal temperature (Japanese Industrial Standard: 20 ° C. ± 15 ° C./JIS Z8703) is a negative pressure (a pressure lower than the atmospheric pressure in terms of absolute pressure). Containing refrigerant is filled. As such a refrigerant, a refrigerant containing water as a main component is mentioned. The “main component” means a component contained most in mass ratio.

  When water is used as the refrigerant, the pressure ratio in the refrigeration cycle is expanded and the degree of superheat of the refrigerant often becomes excessive. The refrigerant caused by the increase in the degree of superheat of the refrigerant in the compression process by causing the compressor 3 to suck the atomized liquid phase refrigerant generated by the atomization mechanism 5 together with the gas phase refrigerant generated by the evaporator 2 The enthalpy increase of is continuously suppressed. As a result, the work performed by the compressor 3 to raise the pressure of the refrigerant to a predetermined pressure can be significantly reduced. That is, the power consumption of the compressor 3 can be saved significantly.

  The refrigeration cycle apparatus 1 further includes a heat absorption circuit 12 and a heat dissipation circuit 13.

  The heat absorption circuit 12 is a circuit for using the liquid phase refrigerant cooled by the evaporator 2 and has necessary equipment such as a pump and an indoor heat exchanger. A part of the heat absorption circuit 12 is located inside the evaporator 2. Inside the evaporator 2, a part of the heat absorption circuit 12 may be located above the liquid surface of the liquid phase refrigerant, or may be located below the liquid surface of the liquid phase refrigerant. The heat absorption circuit 12 is filled with a heat medium such as water or brine.

  The liquid-phase refrigerant stored in the evaporator 2 comes in contact with a member (pipe) that constitutes the heat absorption circuit 12. Thereby, heat exchange is performed between the liquid phase refrigerant and the heat medium inside the heat absorption circuit 12, and the liquid phase refrigerant evaporates. The heat medium inside the heat absorption circuit 12 is cooled by the latent heat of vaporization of the liquid phase refrigerant. For example, when the refrigeration cycle apparatus 1 is an air conditioner that cools a room, the heat medium of the heat absorption circuit 12 cools the room air. The indoor heat exchanger is, for example, a finned tube heat exchanger.

  The heat radiation circuit 13 is a circuit used to take heat from the refrigerant inside the condenser 4 and has necessary equipment such as a pump and a cooling tower. A part of the heat dissipation circuit 13 is located inside the condenser 4. In detail, inside the condenser 4, a part of the heat dissipation circuit 13 is located above the liquid level of the liquid phase refrigerant. The heat dissipation circuit 13 is filled with a heat medium such as water or brine. When the refrigeration cycle apparatus 1 is an air conditioner that cools a room, the condenser 4 is disposed outdoors, and the heat medium of the heat radiation circuit 13 cools the refrigerant of the condenser 4.

  The high temperature gas phase refrigerant discharged from the compressor 3 contacts the member (piping) that constitutes the heat dissipation circuit 13 inside the condenser 4. Thereby, heat exchange is performed between the gas phase refrigerant and the heat medium inside the heat dissipation circuit 13, and the gas phase refrigerant is condensed. The heat medium inside the heat dissipation circuit 13 is heated by the condensation latent heat of the gas phase refrigerant. The heat medium heated by the gas phase refrigerant is cooled, for example, by the outside air or the cooling water in a cooling tower (not shown) of the heat dissipation circuit 13.

  The evaporator 2 is constituted of, for example, a container having heat insulation and pressure resistance. The evaporator 2 stores liquid phase refrigerant and evaporates the liquid phase refrigerant inside. The liquid-phase refrigerant inside the evaporator 2 absorbs heat from the outside of the evaporator 2 and evaporates. That is, the liquid phase refrigerant heated by absorbing heat from the heat absorption circuit 12 evaporates in the evaporator 2. In the present embodiment, the liquid-phase refrigerant stored in the evaporator 2 indirectly contacts the heat medium circulating in the heat absorption circuit 12. That is, a part of the liquid phase refrigerant stored in the evaporator 2 is heated by the heat medium of the heat absorption circuit 12 and used to heat the liquid phase refrigerant in a saturated state. The temperature of the liquid phase refrigerant stored in the evaporator 2 and the temperature of the gas phase refrigerant generated by the evaporator 2 are 5 ° C., for example.

  In the present embodiment, the evaporator 2 is an indirect contact type heat exchanger (for example, a shell-tube heat exchanger). However, the evaporator 2 may be a direct contact type heat exchanger such as a spray type or filler type heat exchanger. That is, the liquid phase refrigerant may be heated by circulating the liquid phase refrigerant in the heat absorption circuit 12. Furthermore, the heat absorption circuit 12 may be omitted.

  The compressor 3 sucks in and compresses the gas phase refrigerant generated by the evaporator 2. The compressor 3 is a speed type compressor (dynamic compressor). A velocity type compressor is a compressor which gives momentum to a gas phase refrigerant and then raises the pressure of the gas phase refrigerant by decelerating. As a speed type compressor, a centrifugal compressor, a mixed flow compressor, an axial flow compressor, etc. may be mentioned. Speed-type compressors are also called turbo-compressors. The compressor 3 may be provided with a variable speed mechanism for changing the rotational speed. An example of the variable speed mechanism is an inverter for driving the motor of the compressor 3. The temperature of the refrigerant at the discharge port of the compressor 3 is, for example, in the range of 100 to 150 ° C.

  The condenser 4 is configured of, for example, a container having heat insulation and pressure resistance. The condenser 4 condenses the gas phase refrigerant compressed by the compressor 3 and stores the liquid phase refrigerant generated by condensing the gas phase refrigerant. In the present embodiment, the gas phase refrigerant indirectly contacts and condenses on the heat medium cooled by releasing heat to the external environment. That is, the gas phase refrigerant is cooled by the heat medium of the heat dissipation circuit 13 and condensed. The temperature of the gas phase refrigerant introduced into the condenser 4 is, for example, in the range of 100 to 150 ° C. The temperature of the liquid phase refrigerant stored in the condenser 4 is 35 ° C., for example.

  In the present embodiment, the condenser 4 is an indirect contact type heat exchanger (for example, a shell tube heat exchanger). However, the condenser 4 may be a direct contact type heat exchanger such as a spray type or filler type heat exchanger. That is, the liquid phase refrigerant may be cooled by circulating the liquid phase refrigerant in the heat radiation circuit 13. Furthermore, the heat dissipation circuit 13 may be omitted.

  The suction pipe 6 is a flow path for leading the gas phase refrigerant from the evaporator 2 to the compressor 3. The outlet of the evaporator 2 is connected to the suction port of the compressor 3 via the suction pipe 6.

  The discharge pipe 8 is a flow path for leading the gas phase refrigerant compressed from the compressor 3 to the condenser 4. The discharge port of the compressor 3 is connected to the inlet of the condenser 4 via the discharge pipe 8.

  The atomization mechanism 5 is a spray nozzle that atomizes and sprays a liquid phase refrigerant. The atomization mechanism 5 is disposed on a first steam path from the inlet of the suction pipe 6 to the discharge port of the compressor 3. In the present embodiment, the atomization mechanism 5 is attached to the suction pipe 6. The suction pipe 6 constitutes a part of the first steam path. That is, the atomization mechanism 5 is disposed on the first vapor path, and sprays the liquid phase refrigerant toward the first vapor path. The atomization mechanism 5 faces, for example, the suction port of the compressor 3. In this case, the atomized liquid-phase refrigerant generated by the atomization mechanism 5 can be reliably sucked into the compressor 3. When the suction pipe 6 is bent in an L-shape, the atomization mechanism 5 sprays the liquid phase refrigerant on the straight portion of the suction pipe 6 and connected to the compressor 3. Thereby, the number of particles of the liquid phase refrigerant colliding with the inner wall surface of the suction pipe 6 can be reduced.

  In the present embodiment, the refrigerant supply passage 11 connects the evaporator 2 and the atomization mechanism 5. The liquid phase refrigerant stored in the evaporator 2 is supplied to the atomization mechanism 5 through the refrigerant supply passage 11. The refrigerant supply passage 11 may be configured by at least one pipe. The inlet of the refrigerant supply passage 11 is positioned below the liquid surface of the liquid-phase refrigerant stored in the evaporator 2 in the evaporator 2. The refrigerant supply passage 11 may be provided with a pump, a valve, and the like.

  The compressor 3 is provided with a suction port 3 a at the inlet of the compressor 3 and a flow passage wall 3 b of a refrigerant vapor path inside the compressor 3.

  The drain circuit 7 connects the flow path wall surface 3 b and the inside of the evaporator 2.

  As shown in FIG. 2, the atomizing mechanism 5 may be a single-fluid atomizing nozzle that atomizes the liquid phase refrigerant in the liquid phase state. The atomization mechanism 5 includes a nozzle body 51, an injection port 52, and a collision portion 53. The nozzle body 51 is a cylindrical portion connected to one end of the refrigerant supply passage 11. The injection port 52 is provided at the tip of the nozzle body 51. A plurality of injection ports 52 may be provided in the nozzle body 51. The injection port 52 may be a very small hole (orifice). The collision part 53 is disposed on the central axis of the injection port 52. The collision portion 53 has a collision surface 54 which is a flat surface inclined with respect to the central axis of the injection port 52. When the liquid phase refrigerant passes through the injection port 52, a jet 55 of the liquid phase refrigerant is generated. The jet 55 collides with the collision part 53 to atomize the liquid-phase refrigerant and form a flow VP of liquid-phase refrigerant particles. The flow VP of liquid phase refrigerant particles travels in the direction of inclination of the collision surface 54.

  The particles of the liquid-phase refrigerant sprayed from the atomization mechanism 5 preferably have a size such that heat exchange between the gas-phase refrigerant and the particles of the liquid-phase refrigerant can be efficiently performed. The particle size of the liquid phase refrigerant is, for example, in the range of 1 to 10 μm.

  The structure of the atomization mechanism 5 is not limited to the structure shown in FIG. As the atomization mechanism 5, a spray nozzle such as a swirl nozzle, a two-fluid nozzle, or an ultrasonic nozzle may be used. The swirl nozzle is a spray nozzle that atomizes a liquid using centrifugal force. The two-fluid nozzle is a spray nozzle that atomizes the liquid using the relative velocity between the liquid flow and the gas flow. An ultrasonic nozzle is a spray nozzle that atomizes a liquid using ultrasonic waves.

  The return path 9 is a flow path for leading the liquid phase refrigerant from the condenser 4 to the evaporator 2. The return path 9 connects the evaporator 2 and the condenser 4. A pump, a flow control valve or the like may be disposed in the return path 9. The return path 9 may be constituted by at least one pipe.

  Next, the structure of the compressor 3 will be described in detail.

  As shown in FIG. 3, the compressor 3 includes an impeller 47, a rotating shaft 32, a first diffuser 33a, a volute 34, and a housing 35.

  The impeller 47 is attached to the rotating shaft 32, and rotates at high speed. The rotation speed of the impeller 47 and the rotating shaft 32 is, for example, in the range of 5000 to 100000 rpm. The impeller 47 is made of, for example, a material such as aluminum, duralumin, iron, ceramic or the like. The rotating shaft 32 is made of a high strength iron-based material such as S45CH. The impeller 47 has a plurality of blades arranged along the circumferential direction. An inter-blade flow path 38 is formed between adjacent blades. When the impeller 47 rotates, the gas phase refrigerant flowing through each of the plurality of inter-blade flow paths 38 is given a rotational speed.

  The first diffuser 33 a is a flow path for guiding the gas phase refrigerant accelerated in the rotational direction by the impeller 47 to the discharge space 37. The flow passage cross-sectional area of the first diffuser 33 a is expanded from the inter-blade flow passage 38 toward the discharge space 37. This structure decelerates the flow velocity of the gas phase refrigerant accelerated by the impeller 47 and raises the pressure of the gas phase refrigerant. The first diffuser 33a is, for example, a vaneless diffuser constituted by a radially extending flow passage. In order to raise the pressure of the refrigerant effectively, the first diffuser 33a may be a vaned diffuser having a plurality of vanes and a plurality of flow paths partitioned by them.

  The volute 34 is a component forming the suction space 36 and the discharge space 37. The suction space 36 is a flow path for guiding the gas phase refrigerant to be compressed toward the impeller 47. The suction space 36 is located upstream of the impeller 47 and is surrounded by a cylindrical shroud wall which is an inner circumferential surface of the volute 34. The discharge space 37 is a space where the gas phase refrigerant having passed through the first diffuser 33a is collected. The compressed gas-phase refrigerant is led to the outside (discharge pipe 8) of the compressor 3 via the discharge space 37. The cross-sectional area of the discharge space 37 is expanded along the circumferential direction, whereby the flow velocity and angular momentum of the gas-phase refrigerant in the discharge space 37 are kept constant. The volute 34 is made of an iron-based material or an aluminum-based material. Examples of iron-based materials include FC250, FCD400, and SS400. ACD12 etc. are mentioned as an aluminum-type material.

  The housing 35 plays a role of a casing for accommodating various components of the compressor 3 and forms a first diffuser 33a. Specifically, the volute 34 and the housing 35 are combined to form a first diffuser 33 a and a discharge space 37. The housing 35 can be made of the above-described iron-based material or aluminum-based material. When the first diffuser 33a is a vaned diffuser, the plurality of vanes may also be made of the above-described iron-based material or aluminum-based material.

  An inlet guide vane (IGV) may be provided on the upstream side of the suction space 36.

  The drain circuit 7 communicates with the hole provided at the lowermost portion of the flow passage wall 3b of the discharge space.

  Next, the operation and action of the refrigeration cycle apparatus 1 will be described.

  When the refrigeration cycle apparatus 1 is left for a fixed period (for example, at night), the temperature of the interior (refrigerant circuit 10) of the refrigeration cycle apparatus 1 substantially balances with the ambient temperature. The pressure inside the refrigeration cycle apparatus 1 balances to a specific pressure. When the compressor 3 is started, the pressure inside the evaporator 2 gradually decreases, and the liquid phase refrigerant evaporates by absorbing heat from the fluid of the secondary circuit that exchanges heat with the inside air through the heat absorption circuit 12 to A refrigerant is produced. The gas phase refrigerant is sucked and compressed by the compressor 3 and discharged from the compressor 3. The high-pressure gas-phase refrigerant is introduced into the condenser 4 and condensed by the heat-dissipation of the gas-phase refrigerant to the outside air or the like through the heat radiation circuit 13 to produce a liquid-phase refrigerant. The liquid phase refrigerant is sent from the condenser 4 to the evaporator 2 through the return path 9.

  The mist-like liquid phase refrigerant generated by the atomization mechanism 5 is sucked into the compressor 3 together with the gas phase refrigerant generated by the evaporator 2. When the misty liquid-phase refrigerant is sucked into the compressor 3, heat exchange occurs between the gas-phase refrigerant whose temperature is raised by the compressor 3 and the temperature rises, and the misty liquid-phase refrigerant The phase refrigerant is continuously cooled by the evaporation of the misty liquid phase refrigerant. Thereby, the increase in enthalpy of the refrigerant resulting from the increase in the degree of superheat of the refrigerant in the compression process is continuously suppressed. The compression power required by the compressor 3 can be reduced to less than that required for fully adiabatic isentropic compression. The work to be performed by the compressor 3 to raise the pressure of the refrigerant to a predetermined pressure can be significantly reduced. That is, the power consumption of the compressor 3 can be saved significantly. As a result, the efficiency of the refrigeration cycle apparatus 1 is improved.

  According to the structure shown in FIG. 2, it is possible to intensively fly the particles of the liquid-phase refrigerant in the inclination direction of the collision surface 54. For example, when a swirl nozzle is used for the atomization mechanism 5, there is a possibility that the particles of the liquid phase refrigerant spread widely and many of them collide with the inner wall surface of the suction pipe 6 or the inner wall surface of the compressor 3. In this case, the number of particles of liquid phase refrigerant used for continuous cooling of the gas phase refrigerant is reduced. According to the structure of the present embodiment, such disadvantages can be avoided or reduced. As a result, the effect of reducing the compression power can be reliably obtained. Of course, a swirl nozzle can be used as the atomization mechanism 5.

  According to the present embodiment, the liquid phase refrigerant stored in the evaporator 2 is supplied to the atomization mechanism 5 through the refrigerant supply passage 11. A misty liquid-phase refrigerant having a temperature substantially the same as the temperature (saturation temperature) of the gas-phase refrigerant sucked into the compressor 3 is drawn into the compressor 3. In this case, it is possible to prevent the liquid phase refrigerant from flash evaporation and the amount of steam rapidly increasing in the compressor 3. As a result, the increase in compression power accompanying the increase in the amount of steam is suppressed. Since the increase of the compression power accompanying the increase of the amount of steam is suppressed, the above-mentioned mechanism can be used for the compression by the above-mentioned mechanism without significantly reducing the refrigeration capacity even under the operating condition where the compressor input becomes excessive as in the overload operation. The effect of reducing the power can be obtained. In addition, it is possible to prevent the compressor 3 from causing choking due to an increase in the amount of steam.

  The misty liquid-phase refrigerant travels along the inter-blade flow path 38 together with the gas-phase refrigerant, and passes through the first diffuser 33a. At this time, the flow velocity of the gas phase refrigerant decreases, and the momentum is converted into pressure and compressed, and the temperature of the gas phase refrigerant rises. The misty liquid phase refrigerant evaporates by exchanging heat with the high temperature steam. However, when the large diameter liquid phase refrigerant particles are contained, the refrigerant vapor deviates from the streamline of the refrigerant vapor before completely evaporating, and collides with the flow path wall surface 3b of the discharge space. The collided droplets are accumulated at the lowermost portion of the flow path wall surface 3b of the discharge space. Since the discharge space is at a higher position than the evaporator 2, the liquid-phase refrigerant passes through the drain circuit 7 due to the gravity head difference and is discharged to the inside of the evaporator 2. Therefore, it is possible to suppress an increase in the theoretical power of the compressor due to the evaporation of the accumulated liquid phase refrigerant.

(Modification 1)
When the operation is performed in a state where the liquid phase refrigerant is not injected from the atomization mechanism 5, it is conceivable that the liquid phase refrigerant is not accumulated at the lowermost portion of the flow path wall 3b. In this case, a loss due to the high pressure vapor refrigerant in the discharge space 37 leaking to the evaporator 2 occurs through the drain circuit 7. A valve may be provided in the middle of the drain circuit 7, and the drain circuit 7 may be closed in a state where the liquid phase refrigerant is not injected from the atomization mechanism 5.

Second Embodiment
As shown in FIG. 4, the drain circuit 7 connects the flow path wall surface 3 b of the compressor 3 to the condenser 4. As shown in detail in FIG. 5, the compressor 3 has the first impeller 31a and the second impeller 31b attached to the rotation shaft 32, and rotates at high speed. The rotational speeds of the first impeller 31a, the second impeller 31b, and the rotating shaft 32 are, for example, in the range of 5000 to 100,000 rpm. The first impeller 31a and the second impeller 31b are made of, for example, materials such as aluminum, duralumin, iron, and ceramic. The rotating shaft 32 is made of a high strength iron-based material such as S45CH. The first impeller 31a and the second impeller 31b have a plurality of blades arranged along the circumferential direction. An inter-blade flow path 38 is formed between adjacent blades. When the impeller 47 rotates, the gas phase refrigerant flowing through each of the plurality of inter-blade flow paths 38 is given a rotational speed.

  The first diffuser 33a decelerates the flow velocity of the gas phase refrigerant accelerated by the first impeller 31a, and raises the pressure of the gas phase refrigerant. The refrigerant decelerated and pressurized by the first diffuser 33a changes its flow direction toward the center again along the return channel 39, and is sucked into the second impeller 31b. The refrigerant accelerated by the second impeller 31 b flows into the second diffuser 33 b, is again decelerated and pressurized, and discharged from the compressor through the discharge space 37.

  The drain circuit 7 connects the lowermost portion of the return channel 39 and the condenser 4.

  The misty liquid-phase refrigerant travels along the inter-blade flow path 38 together with the gas-phase refrigerant, and passes through the first diffuser 33a. At this time, the flow velocity of the gas phase refrigerant decreases, and the momentum is converted into pressure and compressed, and the temperature of the gas phase refrigerant rises. The misty liquid phase refrigerant evaporates by exchanging heat with the high temperature steam. However, when the large diameter liquid phase refrigerant particles are contained, the refrigerant vapor deviates from the streamline of the refrigerant vapor before completely evaporating, and collides with the flow path wall surface 3 b of the discharge space 37. The impacted droplets accumulate at the bottom of the return channel 39. The accumulated liquid phase refrigerant is discharged to the inside of the condenser 4 through the drain circuit 7 due to the head difference between the discharge space 37 and the condenser 4. In order for the liquid phase refrigerant to flow through the drain circuit 7 due to the head difference, the head difference ΔH of the drain circuit 7 needs to be larger than the pressure difference ΔP of the discharge space 37 and the condenser 4. Specifically, assuming that the density ρ of the liquid-phase refrigerant, the gravitational acceleration g, and the height difference h between the inlet and the outlet of the drain circuit 7, ΔP <ΔH = ρgh needs to be satisfied.

  According to the present embodiment, the temperature of the liquid-phase refrigerant accumulated in the lowermost portion of the return channel is the saturated vapor temperature of the gas-phase refrigerant that has been pressurized by the first impeller 31 a and has become high. By discharging the high temperature liquid phase refrigerant to the condenser 4 instead of the evaporator 2, it is possible to prevent the reduction of the efficiency of the refrigeration cycle apparatus due to the heat loss.

Embodiment 3
As shown in FIG. 1, the drain circuit 7 connects the suction port 3 a of the compressor 3 to the evaporator 2. As shown in detail in FIG. 6, the drain circuit 7 connects the flow path wall surface of the suction port 3 a and the evaporator 2.

  Before being sucked into the first impeller, a part of the liquid phase refrigerant sprayed from the atomization mechanism 5 adheres to the flow path wall surface of the suction port 3a and is accumulated in the lowermost portion of the flow path wall surface of the suction space 36 Do. According to the present embodiment, the accumulated liquid-phase refrigerant is discharged to the evaporator 2 through the drain circuit 7 according to the present embodiment at the lowermost part of the flow path wall surface of the suction port 3a. At this time, the suction space 36 is at the same pressure as the evaporator 2 and the saturated vapor temperature is also the same. Therefore, the liquid phase refrigerant flowing through the drain circuit 7 due to the head difference is also equal to the saturated vapor temperature of the evaporator 2 to which the fluid is discharged, so no heat loss occurs.

  The refrigeration cycle apparatus disclosed in the present specification is useful for air conditioners, chillers, heat storage devices, etc., and is particularly useful for air conditioners such as home air conditioners, business air conditioners and the like.

Reference Signs List 1 refrigeration cycle apparatus 2 evaporator 3 compressor 3a suction port 3b flow path wall surface of refrigerant vapor path 4 condenser 5 atomization mechanism 6 suction pipe 7 drain circuit 8 discharge pipe 9 return path 10 refrigerant circuit 11 refrigerant supply path 12 heat absorption circuit 13 Heat radiation circuit 31a 1st impeller 31b 2nd impeller 32 rotary shaft 33a 1st diffuser 33b 2nd diffuser 34 volute 35 housing 36 suction space 37 discharge space 38 flow path between wings 39 return channel 51 nozzle main body 52 injection port 53 collision part 54 Collision surface 55 jet

Claims (3)

An evaporator for evaporating refrigerant liquid to generate refrigerant vapor;
A compressor installed above the evaporator to suck, compress and discharge the refrigerant vapor generated by the evaporator;
A condenser disposed below the compressor, for introducing and condensing the refrigerant vapor discharged from the compressor to generate a refrigerant liquid;
A flow path for returning the refrigerant liquid from the condenser to the evaporator;
An atomization mechanism for spraying a refrigerant liquid into a refrigerant vapor space of a refrigerant vapor path through which refrigerant vapor flows from the evaporator to the compressor outlet;
From the flow path wall surface of the refrigerant vapor path from the downstream of the atomization mechanism to the outlet of the compressor,
A drain circuit connected to the evaporator or the condenser;
Refrigeration cycle device equipped with. The compressor comprises: a first impeller for imparting a rotational speed to the refrigerant vapor generated by the evaporator;
A first diffuser for reducing the velocity of the refrigerant vapor discharged from the first impeller and increasing the pressure of the refrigerant vapor;
A return channel for receiving the refrigerant vapor discharged from the first diffuser and redirecting the flow;
And a second impeller for providing a rotational speed to the refrigerant vapor that has passed through the return channel,
The drain circuit connects the inside of the condenser and the flow path wall surface of the return channel,
The refrigeration cycle apparatus according to claim 1. The compressor comprises: a first impeller for imparting a rotational speed to the refrigerant vapor generated by the evaporator;
An inlet flow path for introducing the refrigerant vapor into the impeller;
The drain circuit is connected from the inside of the evaporator to a location adjacent to the inlet surface of the impeller on the channel wall surface of the inlet channel.
The refrigeration cycle apparatus according to claim 1.