JP6150907B2 - Refrigeration cycle equipment - Google Patents

Description

  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.
Moreover, since the high-pressure and high-temperature refrigerant flows into the expander shell, there is a problem that the generator (motor) in the expander shell is difficult to be cooled.

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 is rotated by the driving force of the expansion unit, and the expander shell has an inlet part that allows the refrigerant and refrigerating machine oil contained in the refrigerant to flow into the expander shell, and the refrigerant And the refrigerating machine oil is allowed to flow into the expander shell from the inlet portion, and then flows out through the expander shell, and is connected to a pipe on the suction side of the compressor. It is formed, in the expander shell A low pressure in the expander shell, refrigerating machine oil contained in the refrigerant is stored, in which the refrigerating machine oil is supplied to at least one of said inflatable portion and said generator.

  In the present invention, the refrigerant flows from the inlet portion of the expander shell, the refrigerating machine oil contained in the refrigerant is stored in the expander shell, and the refrigerant flows from the outlet portion of the expander shell to the suction side piping of the compressor. . 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 figure which shows the other structural example of the refrigerating-cycle apparatus 100 which concerns on Embodiment 5 of this invention. It is a figure which shows the other structural example 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. It is a block diagram of the refrigerating-cycle apparatus 100 which concerns on Embodiment 7 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 low pressure pipe 22. The low pressure pipe 22 is connected to the evaporator (the load side heat exchanger 2 or the heat source side heat exchanger 4) via the first four-way valve 5. Low temperature and low pressure refrigerant discharged from the evaporator 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. As a result, the refrigerating machine oil 50 contained in the refrigerant discharged from the evaporator is stored in the expander shell 34.
The outlet portion 42 is connected to the piping 21 on the suction side of the compressor 1. The refrigerant that has flowed out of the expander shell 34 passes through the pipe 21 on the suction side of the compressor 1 and is sucked into the compressor 1.

(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 is a pipe on the discharge side of the compressor 1. 10 and the heat source side heat exchanger 4 are connected, and the load side heat exchanger 2 and the low pressure pipe 22 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 low-pressure pipe 22 and a load side. The heat exchanger 2 is connected, and the heat source side heat exchanger 4 and the discharge side pipe 10 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, heating operation and 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 discharge-side piping 10 of the compressor 1 and is cooled via a first four-way valve 5 in the case of a condenser (a supercritical refrigerant such as CO ₂ ). The refrigerant is condensed in the load side heat exchanger 2 acting as a condenser, and becomes liquid refrigerant and flows out of 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 unit 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 flows into the expander shell 34 from the inlet 41 of the expander 3 through the low-pressure pipe 22.
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 low-pressure side pipe 21 of the compressor 1. The gas refrigerant flowing out from the outlet portion 42 of the expander 3 is sucked into the compressor 1 through the low-pressure side pipe 21 of the compressor 1.

  In this way, all of the low-pressure gas refrigerant that has flowed out of the evaporator flows into the expander shell 34, and in the expander shell 34, the refrigerating machine oil 50 contained in the gas refrigerant is separated, and the expander shell 34 It is stored in. 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.

<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 flows through the discharge-side piping 10 of the compressor 1 and passes through the first four-way valve 5 to provide a condenser (a cooler in the case of a supercritical refrigerant such as CO ₂ ). Is condensed by the heat source side heat exchanger 4 acting as a 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 part 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 flows into the expander shell 34 from the inlet 41 of the expander 3 via the low-pressure pipe 22. The gas refrigerant flowing out from the outlet portion 42 of the expander 3 is sucked into the compressor 1 through the low-pressure side pipe 21 of the compressor 1.

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 of the refrigerating machine oil 50 is substantially the same as the oil amount flowing into the expander shell 34.
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 amount 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.

Further, in the first embodiment, the expander shell 34 has an inlet portion 41 into which the refrigerant flows and an outlet portion 42 through which the refrigerant flowing in from the inlet portion 41 flows into the pipe 21 on the suction side of the compressor 1. The refrigerating machine oil 50 formed and contained in the refrigerant flowing into the expander shell 34 is stored, and the refrigerating machine oil 50 is supplied to at least one of the expansion unit and the generator.
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, since the low-temperature and low-pressure refrigerant that has flowed out of the evaporator flows into the expander shell 34, the generator 32 can be cooled. Therefore, the efficiency reduction of the generator 32 can be suppressed.
Moreover, since the temperature rise in the expander shell 34 can be suppressed, heat exchange between the refrigerant in the expansion unit 31 and the gas refrigerant in the expander shell 34 is difficult to be performed, and the expansion unit 31 transfers to the evaporator. An increase in the enthalpy of the refrigerant flowing in can be suppressed, and a decrease in the refrigerating capacity can be reduced.

  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 flowing out from the expander shell 34 flows into the pipe 21 on the suction side of the compressor 1, the refrigerant is refrigerated in the expander shell 34 regardless of the internal pressure (high pressure shell or low pressure shell) of the compressor shell 15. The machine oil 50 can be stored.

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, a 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 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 52 is further provided.
The oil return pipe 52 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 52 is provided with 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.

  Instead of the on-off valve 54, a flow rate adjusting valve whose opening degree can be varied may be provided. Alternatively, the small amount of the refrigerating machine oil 50 may be returned at all times by omitting the on-off valve 54 and adjusting the pipe diameter and length of the oil return pipe 52.

  Further, by reducing the height of the outlet portion 42 of the expander shell 34, the amount of the refrigerating machine oil 50 stored in the expander shell 34 is reduced, and the amount of the refrigerating machine oil 50 stored in the compressor shell 15 is reduced. Will increase. For this reason, the height of the outlet portion 42 of the expander shell 34 may be set according to the minimum amount of oil in the compressor shell 15.

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.
Further, when the refrigerating machine oil 50 in the expander shell 34 is excessively stored, the refrigerating machine oil 50 can be returned into the compressor shell 15.
Further, for example, even when the position of the outlet portion 42 cannot be formed at a desired position due to restrictions due to the structure in the expander 3, the compression is performed regardless of the height of the outlet portion 42 of the expander shell 34. Oil can be returned to the machine 1.

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 includes a first low-pressure pipe 22 branched and joined to the suction-side pipe 21 in addition to the configuration of the first embodiment. A bypass pipe 23 is further provided. That is, the first bypass pipe 23 branches a flow path from the evaporator (the load side heat exchanger 2 or the heat source side heat exchanger 4) to the inlet portion 41 of the expander shell 34, and the outlet portion of the expander shell 34. It joins the flow path from 42 to the compressor 1.

  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 refrigerant flowing into the expander shell 34. For this reason, the refrigerant in the expansion part 31 and the refrigerant flowing into the expander shell 34 exchange heat.

In the fourth embodiment, a part of the refrigerant flowing out from the evaporator flows into the expander shell 34 from the pipe 10, and the other part from the first bypass pipe 23 to the pipe 21 on the suction side of the compressor 1. Flow into.
For this reason, compared with the case where all the refrigerant | coolants which flowed out from the evaporator 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 section 31 and the 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.
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.

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 low pressure pipe 22 or the first bypass pipe 23 are selected so that the flow rate of the refrigerant passing through the low pressure pipe 22 is smaller than the flow rate of the refrigerant passing through the first bypass pipe 23.
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 adjusting valve or the like may be provided in the low pressure pipe 22 or the first bypass pipe 23 so as 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.

(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, an oil return pipe 52 that causes the refrigerating machine oil 50 in the expander shell 34 to flow into the pipe 21 on the suction side of the compressor 1, and expansion from the evaporator The first bypass pipe 23 that branches the flow path leading to the inlet portion 41 of the expander shell 34 and joins the flow path extending from the outlet portion 42 of the expander shell 34 to the compressor 1 may be used. 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 branches the flow path (inflow pipe 35) from the condenser to the expansion unit 31 in addition to the configuration of the first embodiment. A second bypass pipe 61 that flows into the inlet 41 of the shell 34 is provided.
Further, the second bypass pipe 61 circulates the pressure reducing means such as the capillary tube 63 for decompressing the refrigerant flowing through the second bypass pipe 61, the refrigerant branched to the second bypass pipe 61, and the inflow pipe 35. And a heat exchanger 60 for exchanging heat with the refrigerant (the refrigerant flowing from the condenser into the expansion section).
In the expander shell 34 according to the fifth embodiment, the outlet portion 42 joins the pipe 21 on the suction side of the compressor 1 through the outflow pipe 20. The outflow pipe 20 is provided with decompression means such as a capillary tube 24 for decompressing the refrigerant.
In the fifth embodiment, the suction side pipe 21 of the compressor 1 is connected to the evaporator (the load side heat exchanger 2 or the heat source side heat exchanger 4) via the first four-way valve 5.

The operation in the fifth embodiment will be described with a focus on differences from the first embodiment.
The refrigerant flowing out of the condenser passes through the second four-way valve 6 and flows into the inflow pipe 35. A part of the refrigerant flowing through the inflow pipe 35 flows into the second bypass pipe 61. The refrigerant flowing into the second bypass pipe 61 is depressurized by the capillary tube 63 and the temperature is lowered. The refrigerant whose pressure has been reduced by the capillary tube 63 and whose temperature has been reduced is heat-exchanged by the heat exchanger 60 with the high-pressure refrigerant flowing into the expansion portion 31 from the inflow pipe 35 to become a gas refrigerant.
This gas refrigerant flows into the inlet 41 of the expander shell 34. Then, after the refrigerating machine oil 50 contained in the refrigerant is separated, it flows out from the outlet 42 to the outflow pipe 20, is decompressed by the capillary tube 24, and then joins the pipe 21 on the suction side of the compressor 1.

In addition, the structure which decompresses a refrigerant | coolant may be sufficient by adjusting the piping diameter and length of the 2nd bypass piping 61 and the outflow tube 20, without providing decompression means, such as the capillary tubes 24 and 63.
Instead of the capillary tube 63, a decompression device capable of changing the flow rate may be provided. By providing such a pressure reducing device with variable flow rate, the temperature of the refrigerant flowing into the expander shell can be appropriately maintained according to the operating state, and the generator 32 can be effectively cooled. Can do. Further, the occurrence of transient liquid return (liquid back) to the expander shell 34 can be prevented, and the decrease in the oil concentration in the expander shell 34 can be suppressed.

With the above configuration, since the refrigerant flowing into the expander shell 34 can be made into a gas state, for example, even when a liquid bag in which the liquid refrigerant flows out of the evaporator is generated, the liquid state is returned to the expander shell 34. It is possible to prevent the refrigerant from flowing in. Therefore, it can prevent that the refrigerant | coolant of a liquid state mixes into the refrigerator oil 50, and can prevent the fall of oil concentration.
Moreover, the pressure and temperature in the expander shell 34 can be set to desired values by setting the pressure of the refrigerant flowing through the second bypass pipe 61. Therefore, by reducing the temperature in the expander shell 34, the temperature rise of the generator 32 can be suppressed, and the efficiency reduction of the generator 32 can be suppressed.

(Modification 1)
Note that the configuration described in the third embodiment and the configuration described in the fifth embodiment may be combined.
For example, as shown in FIG. 7, in addition to the configuration of the fifth embodiment, the configuration further includes an oil return pipe 52 that allows the refrigerating machine oil 50 in the expander shell 34 to flow into the pipe 21 on the suction side of the compressor 1. good. Even in such a configuration, the same effect as described above can be obtained.
Further, the refrigerating machine oil 50 stored in the expander shell 34 is supplied to the expander 31 and the generator 32 by setting the pressure in the expander shell 34 higher than the refrigerant passing through the expander 31. Refueling using differential pressure is possible as a method, and the reliability of the expander 3 is improved. Further, since the pressure on the suction side of the compressor 1 is lower than the pressure in the expander shell 34, the refrigerating machine oil 50 in the expander shell 34 can be reliably returned to the compressor 1 by the differential pressure.

(Modification 2)
As shown in FIG. 8, in addition to the configuration described in the fifth embodiment, the flow path (low pressure pipe 22) from the evaporator to the compressor 1 is further branched to exchange heat in the second bypass pipe 61. A third bypass pipe 65 that joins the downstream side of the vessel 60 may be further provided.
With such a configuration, even when the refrigerant flowing out of the evaporator and flowing through the low-pressure pipe 22 is in a wet state, the wet state refrigerant and the second bypass pipe 61 pass through the gas state by the heat exchanger 60. Since the mixed refrigerant is combined, the wet refrigerant can be heated, and the liquid back to the expander shell 34 can be suppressed.

Embodiment 6 FIG.
The sixth embodiment will be described mainly with respect to differences from the fifth embodiment, and the same components as those of the fifth embodiment will be denoted by the same reference numerals and description thereof will be omitted.

FIG. 9 is a configuration diagram of a refrigeration cycle apparatus 100 according to Embodiment 6 of the present invention.
As shown in FIG. 9, the refrigeration cycle apparatus 100 according to the sixth embodiment has 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 fifth embodiment. And a fourth bypass pipe 13 that joins the refrigerating machine oil 50 separated by the oil separator 7 with the refrigerant depressurized by the second bypass pipe 61. In the sixth embodiment, the heat exchanger 60 is not necessary.
In the sixth embodiment, the discharge-side pipe 10 of the compressor 1 is connected to the oil separator 7. The oil separator 7 and the first four-way valve 5 are connected by a gas pipe 11.

  As described in the first modification of the fifth embodiment, the oil return pipe 52 that allows the refrigerating machine oil 50 in the expander shell 34 to flow into the pipe 21 on the suction side of the compressor 1 may be provided.

In the refrigeration cycle apparatus 100 according to Embodiment 6, the high-temperature and high-pressure 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 merges with the low-pressure liquid refrigerant flowing through the second bypass pipe 61 via the fourth bypass pipe 13. The low-pressure liquid refrigerant flowing through the second bypass pipe 61 is heated by being joined with the high-temperature refrigerating machine oil 50 to become a gaseous refrigerant. Then, the gasified refrigerant and the refrigerating machine oil 50 flow into the expander shell 34 from the inlet 41.
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.

With the above configuration, the refrigerant flowing into the expander shell 34 can be made into a gas state. It is possible to prevent the refrigerant from flowing in. Therefore, it can prevent that the refrigerant | coolant of a liquid state mixes into the refrigerator oil 50, and can prevent the fall of oil concentration.
Moreover, the pressure and temperature in the expander shell 34 can be set to desired values by setting the pressure of the refrigerant flowing through the second bypass pipe 61. Therefore, by reducing the temperature in the expander shell 34, the temperature rise of the generator 32 can be suppressed, and the efficiency reduction of the generator 32 can be suppressed.
Moreover, since the high temperature refrigerator oil 50 can be cooled by the low temperature refrigerant | coolant which distribute | circulates the 2nd bypass piping 61, the temperature rise of the generator 32 can be suppressed.
Moreover, since the refrigeration oil 50 can be supplied from the oil separator 7, a sufficient amount of oil can be supplied into the expander shell 34.

Embodiment 7 FIG.
In this Embodiment 7, it demonstrates centering around difference with Embodiment 1, the same code | symbol is attached | subjected to the structure same as Embodiment 1, and description is abbreviate | omitted.

FIG. 10 is a configuration diagram of a refrigeration cycle apparatus 100 according to Embodiment 7 of the present invention.
As shown in FIG. 10, the refrigeration cycle apparatus 100 according to the seventh embodiment includes a fifth bypass pipe 37 that branches the inflow pipe 35 and joins the outflow pipe 36 in addition to the configuration of the first embodiment. And a second expansion valve 38 provided in the bypass pipe 37 for expanding the refrigerant.
The fifth bypass pipe 37 branches the flow path (inflow pipe 35) from the condenser to the expansion part 31, and joins the flow path (outflow pipe 36) from the expansion part 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 fifth 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 fifth 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 fifth bypass pipe 37. The refrigerant flowing through the fifth 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 fifth 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.

  The configuration of the seventh embodiment can be applied to any of the configurations of the first to sixth embodiments described above.

  DESCRIPTION OF SYMBOLS 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, 13 4th bypass Piping, 15 Compressor shell, 17 Motor section, 18 Compression section, 20 Outflow pipe, 21 Piping, 22 Low pressure piping, 23 First bypass piping, 24 Capillary tube, 31 Expansion section, 32 Generator, 33 Rotating shaft, 34 Expansion Machine shell, 35 inlet pipe, 36 outlet pipe, 37 fifth bypass pipe, 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, 52 Oil return pipe, 54 open / close valve, 60 heat exchanger, 61 second bypass pipe, 63 capillary tube, 65 third bypass pipe, 100 refrigeration cycle apparatus, 200 Control device.

Claims (12)

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
An inlet for allowing the refrigerant and refrigerating machine oil contained in the refrigerant to flow into the expander shell;
The refrigerant and the refrigerating machine oil are allowed to flow from the inlet portion into the expander shell, and then flow out through the expander shell, and are connected to a pipe on the suction side of the compressor. Formed,
The expander shell has a low pressure inside,
A refrigerating cycle device in which refrigerating machine oil contained in the refrigerant is stored in the expander shell, and the refrigerating machine oil is supplied to at least one of the expansion unit and the generator. The outlet portion of the expander shell is
The refrigeration cycle apparatus according to claim 1, 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. The refrigeration cycle apparatus according to claim 1, further comprising a return oil pipe that allows the refrigerating machine oil in the expander shell to flow into a pipe on the suction side of the compressor. The refrigeration cycle apparatus according to any one of claims 1 to 3, wherein the refrigerant that has flowed out of the evaporator flows into the inlet portion of the expander shell. The first bypass pipe for branching a flow path from the evaporator to the inlet portion of the expander shell and joining the flow path from the outlet portion of the expander shell to the compressor. The refrigerating cycle apparatus as described in any one of 1-4 . The flow rate of the refrigerant flowing from the inlet portion of the expander shell is
The refrigeration cycle apparatus according to claim 5 , wherein the refrigeration cycle apparatus is less than a flow rate of the refrigerant passing through the first bypass pipe. A second bypass pipe for branching a flow path from the condenser to the expansion section, depressurizing the refrigerant, and flowing into the inlet section of the expander shell;
The heat exchanger which heat-exchanged the said refrigerant | coolant branched and pressure-reduced to the said 2nd bypass piping, and the said refrigerant | coolant which flows in into the said expansion part from the said condenser was further provided. The refrigeration cycle apparatus according to item. The refrigeration cycle apparatus according to claim 7 , wherein the pressure in the expander shell is higher than the pressure flowing out from the expansion section. The refrigeration cycle according to claim 7 or 8 , further comprising a third bypass pipe that branches a flow path from the evaporator to the compressor and joins the second bypass pipe to the downstream side of the heat exchanger. apparatus. A second bypass pipe for branching a flow path from the condenser to the expansion section, depressurizing the refrigerant, and flowing into the inlet section of the expander shell;
An oil separator for separating the refrigerating machine oil contained in the refrigerant discharged from the compressor;
A fourth bypass pipe for joining the refrigerant oil separated by the oil separator with the refrigerant depressurized by the second bypass pipe;
The refrigeration cycle apparatus according to any one of claims 1 to 4, further comprising: A fifth 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 provided in the fifth bypass pipe and expanding the refrigerant;
The refrigeration cycle apparatus according to any one of claims 1 to 10 , wherein when the condition set in advance is satisfied, the refrigerant flows through the fifth bypass pipe. 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,
The refrigeration cycle apparatus according to claim 11 , 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.

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