WO2015104822A1

WO2015104822A1 - Refrigeration cycle device

Info

Publication number: WO2015104822A1
Application number: PCT/JP2014/050256
Authority: WO
Inventors: 加藤　央平; 裕輔島津; 悟梁池; 大坪　祐介; 進一内野
Original assignee: 三菱電機株式会社
Priority date: 2014-01-09
Filing date: 2014-01-09
Publication date: 2015-07-16
Also published as: JPWO2015104822A1; EP3104101A1; JP6150906B2; EP3104101A4

Abstract

This refrigeration cycle device (100) is provided with the following: a compressor (1); a condenser; an expander (3); and a refrigerant circuit that is connected to an evaporator by a piping and in which a refrigerant circulates. The expander (3) includes the following: an expander shell (34) that constitutes an outer shell; an expansion part (31) that is disposed inside the expander shell (34), expands refrigerant which flowed out from the condenser to generate drive force, and causes the expanded refrigerant to flow into the evaporator; and a power generator (32) that is disposed inside the expander shell (34) and that is rotated by the drive force of the expansion part (31). The expander shell (34) retains a refrigeration oil (50) contained in the refrigerant discharged from the compressor (1), and the refrigeration oil (50) is supplied to the expansion part (31) and/or the power generator (32).

Description

Refrigeration cycle equipment

The present invention relates to a refrigeration cycle apparatus including an expander that recovers expansion power of a refrigerant as electric power.

In the conventional refrigeration cycle apparatus, the refrigerant circuit has a compressor and an expander. The compressor casing and the expander casing communicate with each other through a communication pipe, and the discharge pipe and the expander casing communicate with each other through a branch outflow pipe to equalize the pressure in both casings. An oil amount adjusting valve is provided in an oil circulation pipe that connects the oil reservoirs of the compressor and the expander. It has been proposed that when the oil amount adjustment valve is opened, the oil sump in the compressor casing and the oil sump in the expander casing communicate with each other, and the refrigeration oil moves through the oil distribution pipe (for example, , See Patent Document 1).

In the conventional refrigeration cycle apparatus, the refrigerant circuit is provided with a compressor and an expander. In the compressor, the refrigerant compressed by the compression mechanism is discharged into the internal space of the compressor casing. In the compressor, the refrigeration oil accumulated at the bottom of the compressor casing is supplied to the compression mechanism. It has been proposed that the refrigerating machine oil accumulated at the bottom of the compressor casing is directly introduced into the expansion mechanism of the expander through the oil supply pipe (for example, see Patent Document 2).

JP 2007-285684 A (summary) JP 2008-224053 A (summary)

In the technique described in Patent Document 1, a compressor shell (compressor casing) and an expander shell (expander casing) are connected by piping, and a part of the gas refrigerant in the compressor shell is caused to flow into the expander shell. Thus, a part of the refrigerating machine oil in the compressor is caused to flow into the expander shell.
For this reason, the pressure in a compressor shell and the pressure in an expander shell become the same pressure. Therefore, for example, a configuration in which the pressure in the compressor shell is different from the pressure in the expander shell, such as a configuration in which the compressor shell has a high pressure and the expander shell has a low pressure, or vice versa. There was a problem that it was not possible.

In the technique described in Patent Document 2, the refrigerating machine oil accumulated at the bottom of the compressor shell (compressor casing) is directly introduced into the expansion section (expansion mechanism) in the expander through the oil supply pipe.
For this reason, when the refrigerating machine oil in the compressor shell is exhausted, there is a problem that the oil cannot be supplied into the expander.
Further, when the refrigeration oil circulates through the oil supply pipe, the refrigerant dissolved in the refrigeration oil is decompressed and foamed, and the refrigerant gas is mixed into the refrigeration oil, resulting in deterioration in lubricity.

The present invention has been made to solve the above-described problems, and can store refrigerating machine oil in the expander shell regardless of the pressure in the compressor shell, thereby depleting the refrigerating machine oil in the expander. It aims at obtaining the refrigerating-cycle apparatus which can be suppressed.

A refrigeration cycle apparatus according to the present invention includes a refrigerant circuit in which a compressor, a condenser, an expander, and an evaporator are connected by piping and the refrigerant circulates, and the expander includes an expander shell constituting an outer shell, An expansion unit that is disposed in the expander shell, expands the refrigerant that has flowed out of the condenser, generates a driving force, and flows the expanded refrigerant into the evaporator, and is disposed in the expander shell. A generator that rotates by the driving force of the expansion unit, and the expander shell stores refrigerating machine oil contained in the refrigerant discharged from the compressor, and the refrigerating machine oil is stored in the expansion unit and It is supplied to at least one of the generators.

In the present invention, the refrigerating machine oil contained in the refrigerant discharged from the compressor is stored in the expander shell. For this reason, refrigeration oil can be stored in the expander shell regardless of the pressure in the compressor shell, and exhaustion of the refrigeration oil in the expander can be suppressed.

1 is a configuration diagram of a refrigeration cycle apparatus 100 according to Embodiment 1 of the present invention. It is a block diagram of the expander 3 of the refrigerating-cycle apparatus 100 which concerns on Embodiment 2 of this invention. It is a block diagram of the refrigerating cycle apparatus 100 which concerns on Embodiment 3 of this invention. It is a block diagram of the refrigerating-cycle apparatus 100 which concerns on Embodiment 4 of this invention. It is a figure which shows the other structural example of the refrigerating-cycle apparatus 100 which concerns on Embodiment 4 of this invention. It is a block diagram of the refrigerating cycle apparatus 100 which concerns on Embodiment 5 of this invention. It is a block diagram of the refrigerating cycle apparatus 100 which concerns on Embodiment 6 of this invention.

Embodiment 1 FIG.
<Configuration of refrigeration cycle apparatus 100>
FIG. 1 is a configuration diagram of a refrigeration cycle apparatus 100 according to Embodiment 1 of the present invention.
As shown in FIG. 1, the refrigeration cycle apparatus 100 includes a compressor 1, a load side heat exchanger 2, an expander 3, a heat source side heat exchanger 4, a first four-way valve 5, and a second four-way valve 6. Yes. The compressor 1, the load side heat exchanger 2, the expander 3, and the heat source side heat exchanger 4 are connected by a pipe and constitute a refrigerant circuit in which the refrigerant circulates.

(Compressor 1)
The compressor 1 is constituted by, for example, a hermetic compressor. In the compressor 1, an outer shell is constituted by the compressor shell 15. In the compressor shell 15, an electric motor unit 17 and a compression unit 18 are accommodated.
The compressor shell 15 stores refrigeration oil 50. The refrigerating machine oil 50 is supplied to the electric motor unit 17 and the compression unit 18 and used for lubrication.

The compressor 1 sucks low-pressure refrigerant into the compressor shell 15 from the pipe 21 on the suction side. The compression unit 18 is driven by the electric motor unit 17. The low-pressure refrigerant sucked into the compressor shell 15 is compressed by the compression unit 18. The high-pressure refrigerant compressed by the compression unit 18 is discharged to the discharge side pipe 10.
Thus, the pressure inside the compressor shell 15 is low. That is, the compressor shell 15 is a so-called low pressure shell.

In the first embodiment, the case where the pressure in the compressor shell 15 is low will be described, but the present invention is not limited to this.
For example, the compression unit 18 directly sucks the low-pressure refrigerant from the pipe 21 on the suction side. The high-pressure refrigerant compressed by the compression unit 18 is discharged into the compressor shell 15. The refrigerant discharged into the compressor shell 15 may be discharged to the discharge side pipe 10.
As described above, the internal pressure of the compressor shell 15 may be high. That is, the compressor shell 15 may be a so-called high pressure shell.

(Expander 3)
The expander 3 includes an expander shell 34 that forms an outer shell. An expander 31 and a generator 32 (motor) are accommodated in the expander shell 34. The expansion part 31 and the generator 32 are connected by a rotating shaft 33.
In addition, the refrigerating machine oil 50 is stored in the expander shell 34. The refrigerating machine oil 50 is supplied to at least one of the expansion unit 31 and the generator 32 and used for lubrication.

The expansion part 31 has an expansion part inlet 43 through which the refrigerant flows in and an expansion part outlet 44 through which the refrigerant flows out. The expansion part inlet 43 is connected to the inflow pipe 35. The expansion part outlet 44 is connected to the outflow pipe 36.
The inflow pipe 35 is connected to the condenser (the load side heat exchanger 2 or the heat source side heat exchanger 4) via the second four-way valve 6.
The outflow pipe 36 is connected to the evaporator (the load side heat exchanger 2 or the heat source side heat exchanger 4) via the second four-way valve 6.

The expansion part 31 expands the refrigerant that has flowed into the expansion part inlet 43 from the inflow pipe 35 and causes the expanded refrigerant to flow out from the expansion part outlet 44 to the outflow pipe 36. Further, the expansion unit 31 rotationally drives the rotary shaft 33 with expansion power when the refrigerant is expanded.
The generator 32 is connected to the inflating part 31 by the rotating shaft 33 and is rotated by the driving force of the inflating part 31 to generate electric power. Thereby, the expansion power of the expansion part 31 is collect | recovered as electric power.

The expander shell 34 of the expander 3 is formed with an inlet portion 41 through which the refrigerant flows and an outlet portion 42 through which the refrigerant flows out.
The inlet 41 is connected to the discharge-side piping 10 of the compressor 1. The refrigerant discharged from the compressor 1 flows into the expander shell 34. The refrigerant that has flowed into the expander shell 34 is separated into the gas refrigerant and the refrigerating machine oil 50. Thereby, the refrigerating machine oil 50 contained in the refrigerant discharged from the compressor 1 is stored in the expander shell 34.
The outlet part 42 is connected to the gas pipe 11. The gas pipe 11 is connected to the condenser (the load side heat exchanger 2 or the heat source side heat exchanger 4) via the first four-way valve 5.

(Load side heat exchanger 2)
The load side heat exchanger 2 is constituted by, for example, a fin-and-tube heat exchanger. The load side heat exchanger 2 performs heat exchange between air as a load side medium and a refrigerant. Note that the load-side medium is not limited to air, and for example, water or antifreeze may be used as a heat source.

(Heat source side heat exchanger 4)
The heat source side heat exchanger 4 is configured by, for example, a fin-and-tube heat exchanger. The heat source side heat exchanger 4 performs heat exchange between the outside air as the heat source side medium and the refrigerant. The heat source side medium is not limited to the outside air (air), and for example, water or antifreeze liquid may be used as the heat source.

(First four-way valve 5, second four-way valve 6)
The first four-way valve 5 and the second four-way valve 6 are used for switching the flow of the refrigerant circuit.
When the load-side heat exchanger 2 functions as a condenser (heat radiator) and the heat source-side heat exchanger 4 functions as an evaporator (heating operation), the first four-way valve 5 exchanges heat with the gas pipe 11 and the heat source. The load side heat exchanger 2 and the suction side piping 21 of the compressor 1 are connected. The second four-way valve 6 connects the load side heat exchanger 2 and the inflow pipe 35 and connects the outflow pipe 36 and the heat source side heat exchanger 4.
On the other hand, when the load-side heat exchanger 2 functions as an evaporator and the heat-source-side heat exchanger 4 functions as a condenser (heat radiator) (cooling operation), the first four-way valve 5 includes a gas pipe 11 and a load side. The heat exchanger 2 is connected, and the heat source side heat exchanger 4 and the suction side pipe 21 of the compressor 1 are connected.
The second four-way valve 6 connects the heat source side heat exchanger 4 and the inflow pipe 35, and connects the outflow pipe 36 and the load side heat exchanger 2.
If the switching between the heating operation and the cooling operation is not performed, the first four-way valve 5 and the second four-way valve 6 may not be provided.

(Control device 200)
The control device 200 is configured by a microcomputer, for example, and includes a CPU, a RAM, a ROM, and the like, and a control program and the like are stored in the ROM. The control device 200 receives detection values from various sensors that detect the pressure and temperature of the refrigerant in the refrigerant circuit, the temperatures of the load-side medium and the heat-source-side medium, and the like. The control device 200 controls each component of the refrigeration cycle apparatus 100 based on the detection value from each sensor. Further, the control device 200 controls switching of the first four-way valve 5 and the second four-way valve 6.

Next, the heating operation and the cooling operation in the refrigeration cycle apparatus 100 of the present embodiment will be described.

<Operation of refrigerant during heating operation>
During the heating operation, the first four-way valve 5 and the second four-way valve 6 are switched to the state shown by the dotted line in FIG.
The compressor 1 compresses the low-pressure refrigerant in the compressor shell 15 and discharges the high-temperature and high-pressure gas refrigerant to the discharge-side pipe 10. The gas refrigerant discharged from the compressor 1 includes the refrigerating machine oil 50 in the compressor shell 15.

The high-temperature and high-pressure gas refrigerant discharged from the compressor 1 flows through the piping 10 on the discharge side of the compressor 1 and flows into the expander shell 34 from the inlet 41 of the expander 3. The gas refrigerant that has flowed into the expander shell 34 is separated in the expander shell 34 at least a part of the refrigerating machine oil 50 contained in the gas refrigerant, and the separated refrigerating machine oil 50 is stored in the expander shell 34. The Then, the gas refrigerant and the remaining refrigeration oil 50 contained in the gas refrigerant flow out from the outlet portion 42 to the gas pipe 11.

In this way, all of the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 flows into the expander shell 34, and the refrigerating machine oil 50 contained in the gas refrigerant is separated in the expander shell 34 to expand the expander shell. 34 is stored. The refrigerating machine oil 50 stored in the expander shell 34 is supplied to the electric motor unit 17 and the compression unit 18 via the rotary shaft 33 and used for lubrication.

The gas refrigerant flowing out from the outlet 42 of the expander 3 to the gas pipe 11 passes through the first four-way valve 5 and acts as a condenser (a cooler in the case of a supercritical refrigerant such as CO ₂ ). It is condensed by the heat exchanger 2 and becomes a liquid refrigerant and flows out from the load side heat exchanger 2. Thereafter, the liquid refrigerant that has flowed out of the load-side heat exchanger 2 passes through the second four-way valve 6 and flows into the expansion portion inlet 43 in the expander 3 through the inflow pipe 35. The liquid refrigerant that has flowed into the expansion section inlet 43 is expanded by the expansion section 31 and becomes a low-pressure two-phase refrigerant and flows out from the expansion section outlet 44 through the outflow pipe 36. At this time, the generator 32 connected to the rotating shaft 33 is rotated by the driving force of the expansion part 31.

The low-pressure two-phase refrigerant that has flowed out of the expansion section 31 passes through the second four-way valve 6 and flows into the heat source side heat exchanger 4 that functions as an evaporator. The low-pressure two-phase refrigerant that has flowed into the heat source side heat exchanger 4 exchanges heat with the heat source side medium (outside air), absorbs heat and evaporates, becomes a low pressure gas refrigerant, and flows out of the heat source side heat exchanger 4. The low-pressure gas refrigerant flowing out from the heat source side heat exchanger 4 passes through the first four-way valve 5 and is sucked into the compressor 1 through the low-pressure side pipe 21 of the compressor 1.

<Refrigerant operation during cooling operation>
The difference from the heating operation will be mainly described.
During the cooling operation, the first four-way valve 5 and the second four-way valve 6 are switched to the state shown by the solid line in FIG.
The gas refrigerant discharged from the compressor 1 passes through the expander shell 34 of the expander 3 and flows out to the gas pipe 11. The gas refrigerant flowing out to the gas pipe 11 passes through the first four-way valve 5 and is condensed in the heat source side heat exchanger 4 acting as a condenser (a cooler in the case of a supercritical refrigerant such as CO ₂ ). It becomes liquid refrigerant and flows out of the heat source side heat exchanger 4. Thereafter, the liquid refrigerant that has flowed out of the heat source side heat exchanger 4 passes through the second four-way valve 6 and the inflow pipe 35, is expanded by the expansion unit 31, and flows out as a low-pressure two-phase refrigerant.

The low-pressure two-phase refrigerant that has flowed out of the expansion section 31 passes through the second four-way valve 6 and flows into the load-side heat exchanger 2 that functions as an evaporator. The low-pressure two-phase refrigerant that has flowed into the load-side heat exchanger 2 exchanges heat with the load-side medium (air), absorbs heat and evaporates, becomes a low-pressure gas refrigerant, and flows out of the load-side heat exchanger 2. The low-pressure gas refrigerant flowing out from the load-side heat exchanger 2 passes through the first four-way valve 5 and is sucked into the compressor 1 through the low-pressure side pipe 21 of the compressor 1.

<Relationship between the amount of refrigeration oil 50 flowing into the expander shell 34 and the amount of oil flowing out>
As described above, at least a part of the refrigerating machine oil 50 contained in the gas refrigerant is separated from the gas refrigerant flowing into the expander shell 34 in the expander shell 34, and the separated refrigerating machine oil 50 is used as the expander shell. 34 is stored. Then, the gas refrigerant and the remaining refrigeration oil 50 contained in the gas refrigerant flow out from the outlet portion 42 to the gas pipe 11.
That is, the oil amount Go1 of the refrigerating machine oil 50 flowing into the expander shell 34 from the compressor 1 flows out from the expander shell 34 to the gas pipe 11 and the oil quantity Go2 of the refrigerating machine oil 50 stored in the expander shell 34. It is equal to the sum with the oil amount Go3 of the refrigerating machine oil 50 to be performed.
That is, the oil amount Go3 of the refrigerating machine oil 50 contained in the gas refrigerant flowing out from the expander shell 34 is smaller than the oil quantity Go1 of the refrigerating machine oil 50 contained in the gas refrigerant discharged from the compressor 1.
As a result, the amount of the refrigerating machine oil 50 flowing into the condenser (the load-side heat exchanger 2 or the heat source-side heat exchanger 4) is also reduced, so that the pressure loss in the piping is reduced, and the oil in the condenser is reduced. It is possible to suppress a decrease in heat transfer performance due to accumulation.

When the refrigerating machine oil 50 stored in the expander shell 34 increases and the oil level of the refrigerating machine oil 50 reaches the outlet 42 of the expander shell 34, it is included in the gas refrigerant flowing out from the expander shell 34. The oil amount Go3 of the refrigerating machine oil 50 is substantially the same as the oil amount Go1.
The refrigerating machine oil 50 stored in the expander shell 34 is consumed by being supplied to the expansion unit 31 and the generator 32. For example, a part of the refrigerating machine oil 50 supplied to the expansion unit 31 is mixed into the refrigerant in the expansion unit 31 and flows into the compressor 1 through the refrigerant flow path. For this reason, the oil amount Go2 of the refrigerating machine oil 50 stored in the expander shell 34 may decrease.

As described above, in the first embodiment, the expander 3 is disposed in the expander shell 34 constituting the outer shell and the expander shell 34, and expands the refrigerant flowing out of the condenser to generate a driving force. The expansion unit 31 allows the expanded refrigerant to flow into the evaporator, and the generator 32 is disposed in the expander shell 34 and is rotated by the driving force of the expansion unit 31.
For this reason, the motive power at the time of expanding a refrigerant | coolant can be collect | recovered as electric power.

In the first embodiment, the expander shell 34 stores the refrigerating machine oil 50 contained in the refrigerant discharged from the compressor 1, and the refrigerating machine oil 50 is supplied to at least one of the expansion unit 31 and the generator 32. The Further, the expander shell 34 is formed with an inlet portion 41 into which the refrigerant discharged from the compressor 1 flows and an outlet portion 42 through which the refrigerant flowing in from the inlet portion 41 flows out to the condenser.
For this reason, the refrigerating machine oil 50 stored in the expander shell 34 can be supplied to the expansion unit 31 and the power generator 32, and depletion of the refrigerating machine oil 50 in the expander shell 34 can be suppressed.
Further, the refrigeration oil 50 contained in the refrigerant discharged from the compressor 1 can be separated in the expander shell 34. Accordingly, the amount of the refrigerating machine oil 50 flowing into the condenser (the load side heat exchanger 2 or the heat source side heat exchanger 4) can be reduced, the pressure loss in the high pressure side piping is reduced, and the inside of the condenser is reduced. It is possible to suppress a decrease in heat transfer performance due to oil accumulation in the tank.
In addition, since the oil supply pipe as in the technique described in Patent Document 2 is not provided, the refrigerant dissolved in the refrigerating machine oil 50 does not foam, and poor lubrication can be suppressed. Even in a transitional state such as when the compressor 1 is started, the expansion unit 31 and the generator 32 can be lubricated by the refrigerating machine oil 50 stored in the expander shell 34.

Further, since the refrigerant discharged from the compressor 1 to the pipe 10 flows into the expander shell 34, gas refrigerant is supplied into the expander shell 34 regardless of the internal pressure (high pressure shell or low pressure shell) of the compressor shell 15. The refrigerating machine oil 50 can be stored in the expander shell 34.

A generator 32 is disposed in the expander shell 34. Then, the gas refrigerant discharged from the compressor 1 to the pipe 10 passes through the expander shell 34 and flows into the condenser.
For this reason, heat generated by the generator 32 (for example, heat due to copper loss in the windings and iron loss such as the stator) and the gas refrigerant can exchange heat, and the generator 32 can be cooled. Moreover, in the case of heating operation, the heating capacity can be improved by heating the gas refrigerant.

Embodiment 2. FIG.
In the second embodiment, the difference from the first embodiment will be mainly described, and the same components as those in the first embodiment will be denoted by the same reference numerals and the description thereof will be omitted.

FIG. 2 is a configuration diagram of the expander 3 of the refrigeration cycle apparatus 100 according to Embodiment 2 of the present invention.
As shown in FIG. 2A, the outlet portion 42 of the expander shell 34 is configured by an opening provided on the side surface of the expander shell 34. The outlet portion 42 is provided at a position (Lm) higher than the oil level (Ln) when a preset required amount of refrigerating machine oil 50 is stored in the expander shell 34. Here, the required amount set in advance is the minimum amount of oil defined by the specifications of the expander 3 or the like.
In addition, as shown in FIG.2 (b), piping which connects the inside and outside of the expander shell 34 may be provided, and the exit part 42 may be comprised by opening of the edge part of piping. Also in this case, the outlet portion 42 is provided in a position (Lm) higher than the oil level (Ln) when the required amount of the refrigerating machine oil 50 stored in the expander shell 34 is stored. Yes.

With the above configuration, the required amount of refrigerating machine oil 50 set in advance can be stored in the expander shell 34. Therefore, the minimum amount of oil required for the expander 3 can be ensured.

Embodiment 3 FIG.
In this Embodiment 3, it demonstrates centering on difference with Embodiment 1, the same code | symbol is attached | subjected to the structure same as Embodiment 1, and description is abbreviate | omitted.

FIG. 3 is a configuration diagram of the refrigeration cycle apparatus 100 according to Embodiment 3 of the present invention.
As shown in FIG. 3, the refrigeration cycle apparatus 100 according to the third embodiment includes a first pipe that branches the pipe 10 on the discharge side of the compressor 1 and joins the gas pipe 11 in addition to the configuration of the first embodiment. A bypass pipe 12 is further provided. That is, the first bypass pipe 12 branches a flow path from the compressor 1 to the inlet 41 of the expander shell 34, and the condenser (load side heat exchanger 2 or heat source side) from the outlet 42 of the expander shell 34. Merge into the flow path leading to the heat exchanger 4).

Here, since the refrigerant liquefied by the condenser (the load side heat exchanger 2 or the heat source side heat exchanger 4) flows into the expansion unit 31 in the expander 3, the temperature of the refrigerant flowing through the expansion unit 31 is The temperature is lower than that of the gas refrigerant flowing into the expander shell 34. For this reason, the refrigerant in the expansion part 31 and the gas refrigerant flowing into the expander shell 34 exchange heat.

In the third embodiment, a part of the refrigerant discharged from the compressor 1 flows into the expander shell 34 from the pipe 10, and the other part flows into the gas pipe 11 from the first bypass pipe 12.
For this reason, compared with the case where all the refrigerant | coolants discharged from the compressor 1 flow in in the expander shell 34, the refrigerant | coolant flow rate which flows in in the expander shell 34 decreases. Therefore, the amount of heat exchange between the refrigerant in the expansion portion 31 and the gas refrigerant flowing into the expander shell 34 can be reduced.
Therefore, it is possible to suppress an increase in the enthalpy of the refrigerant flowing into the evaporator and reduce the decrease in the refrigerating capacity. Moreover, the fall of the temperature of the refrigerant | coolant which flows in into a condenser can be suppressed, and the fall of a heating capability can also be reduced.
Furthermore, excessive supply of the refrigerating machine oil 50 into the expander shell 34 can be suppressed. Therefore, the oil level of the refrigerating machine oil 50 in the expander shell 34 can be prevented from reaching the generator 32. Further, the refrigerating machine oil 50 in the expander shell 34 is prevented from being taken out of the expander shell 34 abruptly, the increase in pressure loss in the high-pressure side piping in the refrigerant circuit is suppressed, and the heat exchanger performance is improved. Reduction can be suppressed.

In the above configuration, since the size of the expander 3 is smaller than that of the compressor 1, the amount of the refrigerating machine oil 50 contained in the refrigerant flowing out from the expander shell 34 (the oil flow rate taken out) is from the compressor 1. Less than the amount of refrigerating machine oil 50 contained in the discharged refrigerant. That is, an oil amount smaller than the oil flow rate taken out from the compressor 1 may be supplied to the expander 3.
For this reason, the length and diameter of the pipe 10 or the gas pipe 11 are selected so that the flow rate of the refrigerant passing through the pipe 10 is smaller than the flow rate of the refrigerant passing through the first bypass pipe 12.
In this way, by supplying appropriate refrigerant flow rate and oil flow rate to the expander 3, it is possible to suppress the heat exchange amount in the expansion unit 31 and to suppress the exhaustion of the refrigerating machine oil 50 in the expander shell 34. it can.

Note that a flow rate adjustment valve or the like may be provided in the pipe 10 or the first bypass pipe 12 to adjust the flow rate of the refrigerant flowing into the expander shell 34. For example, when the amount of the refrigerating machine oil 50 in the expander shell 34 is smaller than a preset oil amount, the control device 200 increases the flow rate of the refrigerant flowing into the expander shell 34 and stores the refrigerating machine oil 50 stored. The amount of oil may be increased.
The oil amount in the expander shell 34 may be provided with, for example, an oil amount meter, or the oil amount may be determined by measuring the shell temperature with a temperature sensor such as a thermistor.

Embodiment 4 FIG.
In the fourth embodiment, the difference from the first embodiment will be mainly described, and the same components as those in the first embodiment will be denoted by the same reference numerals and the description thereof will be omitted.

FIG. 4 is a configuration diagram of the refrigeration cycle apparatus 100 according to Embodiment 4 of the present invention.
As shown in FIG. 4, the refrigeration cycle apparatus 100 according to the fourth embodiment adds the refrigerating machine oil 50 in the expander shell 34 to the pipe 21 on the suction side of the compressor 1 in addition to the configuration of the first embodiment. An oil return pipe 51 is further provided.
The oil return pipe 51 connects the oil outlet 45 provided at the bottom of the expander shell 34 and the pipe 21 on the suction side of the compressor 1. The oil return pipe 51 is provided with a pressure reducing means such as a capillary tube 53 and an opening / closing valve 54 for opening and closing the flow path.

The control device 200 controls the opening / closing of the opening / closing valve 54. For example, when the oil amount of the refrigerating machine oil 50 in the compressor shell 15 is less than a preset oil amount, the control device 200 opens the on-off valve 54 and compresses a part of the refrigerating machine oil 50 in the expander shell 34. Oil is returned into the machine shell 15.
The oil amount in the compressor shell 15 may be provided with, for example, an oil amount meter, or the oil amount may be determined by measuring the shell temperature with a temperature sensor such as a thermistor.

In the above description, the case where the pressure reducing means such as the capillary tube 53 and the opening / closing valve 54 for opening and closing the flow path are provided in parallel has been described. A valve may be provided. Further, the on-off valve 54 may be omitted, and a small amount of the refrigerating machine oil 50 may always be returned.

With the above configuration, the refrigerating machine oil 50 in the expander shell 34 can be returned to the compressor 1, so that the amount of refrigerating machine oil 50 contained in the refrigerant discharged from the compressor 1 (the amount of oil taken out) at the time of startup, for example. In many cases, the exhaust of the refrigerating machine oil 50 in the compressor shell 15 can be suppressed.

(Modification)
Note that the configuration described in the third embodiment and the configuration described in the fourth embodiment may be combined.
For example, as shown in FIG. 5, in addition to the configuration of the first embodiment, the refrigerating machine oil 50 in the expander shell 34 flows into the suction-side pipe 21 of the compressor 1, and the compressor 1 The first bypass pipe 12 may be further provided that branches the flow path leading to the inlet 41 of the expander shell 34 and joins the flow path from the outlet 42 of the expander shell 34 to the condenser. Even in such a configuration, the same effect as described above can be obtained.

Embodiment 5 FIG.
The fifth embodiment will be described with a focus on differences from the first embodiment, and the same components as those of the first embodiment will be denoted by the same reference numerals and the description thereof will be omitted.

FIG. 6 is a configuration diagram of a refrigeration cycle apparatus 100 according to Embodiment 5 of the present invention.
As shown in FIG. 6, the refrigeration cycle apparatus 100 according to the fifth embodiment includes an oil separator 7 that separates the refrigeration oil 50 contained in the refrigerant discharged from the compressor 1 in addition to the configuration of the first embodiment. Is further provided.
In the expander shell 34 in the fifth embodiment, the inlet 41 is connected to the oil separator 7 by the outflow pipe 13. In the fifth embodiment, the discharge-side piping 10 of the compressor 1 is connected to the oil separator 7. Further, the gas pipe 11 is connected to the oil separator 7.

In addition, the refrigeration cycle apparatus 100 according to the fifth embodiment includes an oil return pipe 51 that allows the refrigeration oil 50 in the expander shell 34 to flow into the suction-side pipe 21 of the compressor 1.
The oil return pipe 51 connects the oil outlet 45 provided at the bottom of the expander shell 34 and the pipe 21 on the suction side of the compressor 1. The oil return pipe 51 is provided with a pressure reducing means such as a capillary tube 53 and an opening / closing valve 54 for opening and closing the flow path.
Instead of the capillary tube 53 and the on-off valve 54, an expansion valve whose opening degree can be varied may be provided. Further, the on-off valve 54 may be omitted, and a small amount of the refrigerating machine oil 50 may always be returned.

In the refrigeration cycle apparatus 100 according to the fifth embodiment, all of the refrigerant discharged from the compressor 1 passes through the pipe 10 and flows into the oil separator 7. In the oil separator 7, at least a part of the refrigerating machine oil 50 included in the refrigerant is separated. The refrigerating machine oil 50 separated by the oil separator 7 flows into the expander shell 34 from the inlet 41 through the outflow pipe 13. On the other hand, the gas refrigerant separated by the oil separator 7 passes through the gas pipe 11 and flows into the condenser (the load side heat exchanger 2 or the heat source side heat exchanger 4) via the first four-way valve 5.

The refrigerating machine oil 50 stored in the expander shell 34 is supplied to the electric motor unit 17 and the compression unit 18 through the rotating shaft 33 and used for lubrication and cooling. A part of the refrigerating machine oil 50 stored in the expander shell 34 passes through the oil return pipe 51 and is returned to the compressor 1 from the pipe 21 on the suction side of the compressor 1.

With the above configuration, the refrigerating machine oil 50 separated by the oil separator 7 flows into the expander shell 34. For this reason, compared with the case where the refrigerant discharged from the compressor 1 flows into the expander shell 34, heat exchange between the refrigerant in the expansion portion 31 and the gas refrigerant in the expander shell 34 is less likely to be performed. The increase in the enthalpy of the refrigerant flowing into the evaporator from the expansion unit 31 can be suppressed, and the decrease in the refrigerating capacity can be reduced.
Further, the refrigerant discharged from the compressor 1 flows into the condenser without passing through the expander shell 34. For this reason, the fall of the temperature of the refrigerant | coolant which flows in into a condenser can be suppressed, and the fall of a heating capability can also be reduced.

Further, since the high-temperature refrigerant discharged from the compressor 1 does not flow into the expander shell 34, the temperature rise inside the expander shell 34 can be suppressed. Thereby, the temperature rise of the generator 32 can also be suppressed and the efficiency fall of the generator 32 can be suppressed.

The pressure and temperature in the expander shell 34 can be adjusted by adjusting the pipe diameter and length of the outflow pipe 13 and the oil return pipe 51. Alternatively, the pressure and temperature in the expander shell 34 can be adjusted by providing pressure reducing means in the outflow pipe 13 and the oil return pipe 51. Therefore, by adjusting the temperature in the expander shell 34 to be equal to or lower than the temperature of the refrigerant flowing into the inlet portion 41 of the expansion portion 31, the temperature rise of the refrigerant in the expansion portion 31 can be suppressed, and the refrigerant flowing into the evaporator The increase in enthalpy can be suppressed. Moreover, the temperature rise of the generator 32 can be suppressed by lowering the temperature in the expander shell 34, and the efficiency drop of the generator 32 can be suppressed.

Embodiment 6 FIG.
The sixth embodiment will be described with a focus on differences from the first embodiment, and the same components as those of the first embodiment will be denoted by the same reference numerals and the description thereof will be omitted.

FIG. 7 is a configuration diagram of the refrigeration cycle apparatus 100 according to Embodiment 6 of the present invention.
As shown in FIG. 7, in addition to the configuration of the first embodiment, the refrigeration cycle apparatus 100 according to the sixth embodiment includes a second bypass pipe 37 that branches the inflow pipe 35 and joins the outflow pipe 36, and a second And a second expansion valve 38 provided in the bypass pipe 37 for expanding the refrigerant.
The second bypass pipe 37 branches the flow path (inflow pipe 35) from the condenser to the expansion section 31 and joins the flow path (outflow pipe 36) from the expansion section 31 to the evaporator.
The second expansion valve 38 is constituted by, for example, an electronically controlled expansion valve whose opening degree can be varied. The control device 200 controls the opening degree of the second expansion valve 38 according to preset conditions.
An opening / closing valve for opening and closing the flow path of the second bypass pipe 37 may be provided, and the opening of the second expansion valve 38 may be fixed. In this case, the control device 200 controls the on-off valve.

When the opening of the second expansion valve 38 is fully closed, the refrigerant does not flow through the second bypass pipe 37 through the inflow pipe 35. In this case, the operation is the same as that in the first embodiment.
On the other hand, when the second expansion valve 38 is opened, the refrigerant flowing through the inflow pipe 35 flows through the second bypass pipe 37. The refrigerant flowing through the second bypass pipe 37 is decompressed by the second expansion valve 38. At this time, since the flow rate of the refrigerant flowing to the expansion unit 31 decreases, the driving of the expansion unit 31 is stopped. In addition, an on-off valve or the like may be provided in the inflow pipe 35 or the outflow pipe 36 to completely stop the refrigerant flowing into the expansion portion 31.
The refrigerant decompressed by the second expansion valve 38 joins the outflow pipe 36, passes through the second four-way valve 6, and flows into the evaporator.

Next, control of the second expansion valve 38 by the control device 200 will be described.
When the preset condition is satisfied, the control device 200 opens the second expansion valve 38, causes the refrigerant to flow through the second bypass pipe 37, and stops the driving of the expansion unit 31.
Here, the preset condition is, for example, at least one of the following (1) to (3).
(1) When the elapsed time since the start of the compressor 1 is equal to or less than a preset time (2) When the amount of the refrigerating machine oil 50 in the expander shell 34 is equal to or less than a preset amount (3) Expansion When the rotational speed of the unit 31 is greater than or equal to a preset upper limit value or less than a lower limit value

With the above configuration, when the preset condition is satisfied, the driving of the inflating portion 31 can be stopped.
Further, when the elapsed time since the start of the compressor 1 is equal to or less than a preset time, the expansion unit 31 is stopped until the discharge pressure of the compressor 1 is sufficiently increased by stopping the driving of the expansion unit 31. Driving can be prevented and liquid back to the compressor 1 can be suppressed.
Further, when the refrigerating machine oil 50 in the expander shell 34 decreases and becomes equal to or less than a preset amount, the expansion unit 31 can be stopped to prevent the expander 3 from being damaged.
Further, when the rotation speed of the expansion section 31 is equal to or higher than a preset upper limit value or lower limit value, the expansion section 31 is stopped without deviating from the desired range by stopping the driving of the expansion section 31. Can be driven.

It should be noted that the configuration of the sixth embodiment can be applied to any of the configurations of the first to fifth embodiments described above.

1 compressor, 2 load side heat exchanger, 3 expander, 4 heat source side heat exchanger, 5 1st 4 way valve, 6 2nd 4 way valve, 7 oil separator, 10 pipe, 11 gas pipe, 12 1st bypass Pipe, 13 Outflow pipe, 15 Compressor shell, 17 Motor part, 18 Compression part, 21 Pipe, 31 Expansion part, 32 Generator, 33 Rotating shaft, 34 Expander shell, 35 Inflow pipe, 36 Outflow pipe, 37 2nd Bypass piping, 38 second expansion valve, 41 inlet section, 42 outlet section, 43 expansion section inlet, 44 expansion section outlet, 45 oil outlet, 50 refrigerating machine oil, 51 oil return pipe, 53 capillary tube, 54 on-off valve, 100 freezing Cycle equipment, 200 control equipment.

Claims

A compressor, a condenser, an expander, and an evaporator are connected by piping, and a refrigerant circuit in which a refrigerant circulates is provided.
The expander is
An expander shell constituting the outer shell;
An expansion unit that is disposed in the expander shell, expands the refrigerant that has flowed out of the condenser, generates a driving force, and flows the expanded refrigerant into the evaporator;
A generator disposed in the expander shell and rotated by the driving force of the expansion section;
Have
The expander shell is
A refrigeration cycle apparatus characterized in that refrigeration oil contained in the refrigerant discharged from the compressor is stored, and the refrigeration oil is supplied to at least one of the expansion section and the generator.
The expander shell is
An inlet part through which the refrigerant discharged from the compressor flows;
The refrigeration cycle apparatus according to claim 1, further comprising: an outlet portion that allows the refrigerant flowing in from the inlet portion to flow out to the condenser.
The outlet portion of the expander shell is
The refrigeration cycle apparatus according to claim 2, wherein the refrigeration cycle apparatus is provided at a position higher than an oil level when a required amount of the refrigeration oil set in advance is stored in the expander shell.
A first bypass pipe for branching a flow path from the compressor to the inlet portion of the expander shell and joining the flow path from the outlet portion of the expander shell to the condenser; The refrigeration cycle apparatus according to claim 2 or 3, characterized in that:
The flow rate of the refrigerant flowing from the inlet portion of the expander shell is
5. The refrigeration cycle apparatus according to claim 4, wherein the refrigeration cycle apparatus is less than a flow rate of the refrigerant passing through the first bypass pipe.
The refrigeration cycle according to any one of claims 2 to 5, further comprising an oil return pipe that allows the refrigerating machine oil in the expander shell to flow into a suction side pipe of the compressor. apparatus.
An oil separator for separating the refrigerating machine oil contained in the refrigerant discharged from the compressor;
The expander shell is
An inlet portion through which the refrigerating machine oil separated by the oil separator flows;
The refrigeration cycle apparatus according to claim 1, wherein an outlet for allowing the refrigerating machine oil in the expander shell to flow out to a pipe on the suction side of the compressor is formed.
A second bypass pipe for branching the flow path from the condenser to the expansion section and joining the flow path from the expansion section to the evaporator;
A second expansion valve that is provided in the second bypass pipe and expands the refrigerant;
The refrigeration cycle apparatus according to any one of claims 1 to 7, wherein the refrigerant flows through the second bypass pipe when a preset condition is satisfied.
The preset condition is:
When the elapsed time from the start of the compressor is equal to or less than a preset time,
When the amount of the refrigerating machine oil in the expander shell is equal to or less than a preset amount,
9. The refrigeration cycle apparatus according to claim 8, wherein the number of rotations of the expansion section is at least one of a preset upper limit value or more and a lower limit value or less.