JP7094824B2 - Refrigeration cycle system - Google Patents

Description

The present disclosure relates to a refrigeration cycle system capable of recovering expansion energy during the expansion stroke of the refrigeration cycle.

A refrigeration cycle including a compression step, a condensation step, an expansion step and an evaporation step is known. This type of refrigeration cycle is configured by arranging components such as a compressor, a condenser, an expansion valve, and an evaporator corresponding to each process on a circulation path through which a refrigerant flows, and is used for, for example, air conditioning. There is. When the refrigeration cycle functions as cooling, the high-temperature compressed refrigerant generated in the compression step is liquefied in the condensation step, decompressed in the expansion step, and then vaporized in the evaporation step to generate cold heat.

In a typical refrigeration cycle, the expansion step is to reduce the pressure of the liquefied refrigerant using a device such as an expansion valve, but in Patent Document 1, instead of the expansion valve, the refrigerant is in a gas-liquid mixed state. It is disclosed that by arranging a two-phase flow turbine that can be driven by (two-phase flow), the system efficiency is improved by recovering the expansion energy generated in the expansion step. Further, Patent Document 2 discloses an example of a two-phase flow turbine.

Jitsukaisho 61-98954 US Pat. No. 5,476,613

Some systems that utilize refrigeration cycles include multiple refrigeration cycles. In this case, if the expansion step of each refrigeration cycle is to be realized by a two-phase flow turbine as in Patent Document 1, two-phase flow turbines are required for the number of refrigeration cycles. Due to the high cost of two-phase flow turbines, such systems are disadvantageous in terms of profitability and there is a limit to the improvement of system efficiency.

At least one embodiment of the present invention has been made in view of the above circumstances and provides a refrigeration cycle system capable of achieving good system efficiency by recovering the expansion energy of the refrigerant in the refrigeration cycle using a low cost configuration. The purpose is to provide.

(1) The refrigeration cycle system according to at least one embodiment of the present invention solves the above-mentioned problems.
Includes a first compressor that compresses the refrigerant, a first condenser that condenses the refrigerant discharged from the first compressor, and a first evaporator that vaporizes the refrigerant discharged from the first condenser. The first refrigeration cycle and
A second compressor that compresses the refrigerant, a second condenser that condenses the refrigerant discharged from the second compressor, and a second evaporator that vaporizes the refrigerant discharged from the second condenser. Including the second refrigeration cycle and
A two-phase flow turbine that can be driven by expanding the refrigerant discharged from the first condenser and the second condenser.
A power generation device mechanically connected to the two-phase flow turbine,
A first distribution flow path configured to supply the refrigerant discharged from the two-phase flow turbine to the first compressor and the second compressor, respectively.
To prepare for.

According to the configuration of (1) above, at least a part of the expansion stroke in the plurality of refrigeration cycles constituting the system is carried out in a common two-phase flow turbine. As a result, the expansion energy generated in the expansion stroke of each refrigeration cycle can be recovered by the two-phase flow turbine, and good system efficiency can be achieved. Further, since the two-phase flow turbine is provided in common to a plurality of refrigeration cycles, good system efficiency can be obtained while suppressing the cost as compared with the case where the two-phase flow turbines are provided for each of the refrigeration cycles.

(2) In some embodiments, in the configuration of (1) above,
The first distribution flow path is
A first expansion valve provided between the two-phase flow turbine and the first evaporator,
A second expansion valve provided between the two-phase flow turbine and the second evaporator,
To prepare for.

According to the configuration of (2) above, in the first distribution flow path through which the refrigerant discharged from the two-phase flow turbine flows, the first expansion valve constituting the first refrigeration cycle and the second refrigeration cycle constituting the second refrigeration cycle are configured. Two expansion valves are provided. That is, the refrigerant discharged from the two-phase flow turbine is distributed to the first refrigeration cycle and the second refrigeration cycle via the first expansion valve and the second expansion valve provided in the first distribution flow path. In such a configuration, since the two-phase flow turbine is provided on the upstream side of the first expansion valve and the first expansion valve, expansion energy can be recovered in a region where the heat head is large, and good system efficiency can be achieved.

(3) In some embodiments, in the configuration of (2) above,
By adjusting the opening degree of each of the first expansion valve and the second expansion valve, the distribution ratio of the refrigerant to the first refrigeration cycle and the second refrigeration cycle can be adjusted from the two-phase flow turbine. It is composed.

According to the configuration of (3) above, by adjusting the opening degrees of the first expansion valve and the second expansion valve provided on the downstream side of the two-phase flow turbine, the first refrigeration cycle and the first refrigeration cycle from the two-phase flow turbine and the second expansion valve are adjusted. 2 The distribution ratio to the refrigeration cycle can be freely controlled. As a result, the refrigerant after energy recovery in the two-phase flow turbine can be distributed at a flow rate suitable for the first refrigeration cycle and the second refrigeration cycle, so that better system efficiency can be achieved.

(4) In some embodiments, in any one of the above (1) to (3),
A gas-liquid separator provided on the downstream side of the two-phase flow turbine,
A second distribution flow path configured to supply the gas phase component of the refrigerant separated by the brackish water separator to the first compressor and the second compressor, respectively.
To prepare for.

According to the configuration of (4) above, the refrigerant after energy recovery discharged from the two-phase flow turbine can be separated into a gas phase component and a liquid phase component by a gas-liquid separator. Then, the gas phase component separated by the gas-liquid separator is returned to the first compressor and the second compressor of each refrigeration cycle via the second distribution flow path. As a result, it becomes possible to recompress and condense the gas phase component that does not contribute to the heat of vaporization, and the system efficiency can be further improved.

(5) In some embodiments, in any one of the above (1) to (4),
The two-phase flow turbine is
A first nozzle chamber including at least one first turbine nozzle configured to supply the refrigerant flowing from the first condenser to the turbine blades.
A second nozzle chamber including at least one second turbine nozzle configured to supply the refrigerant flowing from the second condenser to the turbine blades.
Equipped with
The first nozzle chamber and the second nozzle chamber are separated from each other.

According to the configuration of (5) above, the two-phase flow turbine is driven by a two-phase flow (mixed flow of gas phase component and liquid phase component) refrigerant introduced from the condenser of each refrigeration cycle. This two-phase flow turbine introduces the refrigerant flowing in from the first condenser of the first refrigeration cycle and supplies it to the turbine blades, and the refrigerant flowing in from the second condenser of the second refrigeration cycle. It is equipped with a second turbine nozzle that is introduced and supplied to the turbine blades. The first turbine nozzle and the second turbine nozzle are arranged in the first nozzle chamber and the second nozzle chamber, respectively, and they are separated from each other. As a result, even when there is a pressure difference between the refrigerants introduced from the first condenser and the second condenser into the two-phase flow turbine, energy loss can be suppressed to a low level and efficient power recovery can be performed. ..

(6) In some embodiments, in the configuration of (5) above,
The first turbine nozzle and the second turbine nozzle are tapered-wided nozzles.

According to the configuration of (6) above, a tapered-wide end type nozzle is adopted for the first turbine nozzle and the second turbine nozzle. As a result, the droplets (liquid phase component) contained in the two-phase flow passing through these turbine nozzles are effectively accelerated by the gas phase component, and the turbine moving blade can be driven more efficiently.

(7) In some embodiments, in the configuration of (6) above,
The first turbine nozzle and the second turbine nozzle are formed so that the area expansion ratio of the throat area with respect to the outlet area decreases as the pressure ratio of the nozzle inlet pressure and the nozzle outlet pressure decreases.

According to the configuration of (7) above, the shape of the turbine nozzle used in the two-phase flow turbine is such that the smaller the pressure ratio between the nozzle inlet pressure and the nozzle outlet pressure, the smaller the area expansion ratio of the outlet area with respect to the throat area. Designed. As a result, the expansion of the working fluid on the low pressure cycle side in the nozzle can be optimized and the droplet acceleration in the nozzle can be promoted, so that the turbine blade can be driven more efficiently.

(8) In some embodiments, in the configuration of (6) or (7) above,
The first turbine nozzle and the second turbine nozzle are formed so that the length from the throat portion to the nozzle outlet portion increases as the nozzle inlet pressure decreases.

According to the configuration of (8) above, the length of the turbine nozzle used in the two-phase flow turbine is designed according to the nozzle inlet pressure of the turbine nozzle. For example, when the inlet pressure of the turbine nozzle is small, the flow velocity of the droplet (liquid phase component) contained in the two-phase flow is relatively slow. The flow velocity at the outlet can be increased. As a result, the turbine blades can be driven more efficiently.

(9) In some embodiments, in any one of the above (5) to (8) configurations.
A first flow rate control valve for adjusting the flow rate of the refrigerant with respect to the first nozzle chamber,
A second flow rate control valve for adjusting the flow rate of the refrigerant with respect to the second nozzle chamber,
Equipped with
In the first flow rate control valve and the second flow rate control valve, the ratio U / C0 of the rotational peripheral speed U of the two-phase flow turbine and the theoretical speed C0 of the nozzle inlet pressure and the turbine outlet pressure is within a predetermined range. Is controlled.

According to the configuration of (9) above, the flow rate of the refrigerant with respect to the first nozzle chamber and the second nozzle chamber has a predetermined ratio U / C0 having a correlation with the system efficiency by the first flow rate control valve and the second flow rate control valve. It is controlled to be within the range. As a result, even when the operating state of the system changes, such as in partial load operation, a predetermined system efficiency is ensured. That is, robust system performance can be obtained for partial loads.

(10) In some embodiments, in the configuration of (9) above,
The first flow rate control valve is provided in the first nozzle chamber including the plurality of the first turbine nozzles.
The second flow rate control valve is provided in the second nozzle chamber including the plurality of the second turbine nozzles.

According to the configuration of (10) above, since the first flow rate control valve and the second flow rate control valve are provided for the first nozzle chamber and the second nozzle chamber, respectively, the refrigerant in the turbine nozzle provided in each nozzle chamber is provided. The flow rate can be adjusted collectively.

(11) In some embodiments, in the configuration of (9) above,
The first flow rate control valve is provided in each of the plurality of first turbine nozzles.
The second flow rate control valve is provided in each of the plurality of second turbine nozzles.

According to the configuration of (11) above, the first flow rate control valve and the second flow rate control valve are provided for each turbine nozzle included in the first nozzle chamber and the second nozzle chamber, respectively, and thus are provided for each turbine nozzle. The flow rate of the refrigerant can be finely adjusted.

(12) In some embodiments, in the configuration of (11) above,
The first turbine nozzle and the second turbine nozzle are reamer nozzles.

According to the configuration of (12) above, since the first turbine nozzle and the second turbine nozzle are configured as reamer nozzles, the flow rate control valve can be easily provided for each turbine nozzle.

According to at least one embodiment of the present invention, it is possible to provide a refrigeration cycle system capable of achieving good system efficiency by recovering the expansion energy of the refrigerant in the refrigeration cycle using a low cost configuration.

It is a block diagram which shows the whole structure of the refrigeration cycle system which concerns on at least one Embodiment of this invention. It is sectional drawing in the axial direction of the two-phase flow turbine of FIG. It is a schematic diagram which shows the 1st nozzle chamber and the 2nd nozzle chamber in the vertical plane in the axial direction of FIG. It is a schematic diagram which shows an example of the 1st turbine nozzle and the 2nd turbine nozzle provided in the 1st nozzle chamber and the 2nd nozzle chamber of FIG. It is a schematic diagram which shows the flow of a two-phase flow refrigerant in a taper-send wide type nozzle. It is a modification of FIG. This is a first modification of FIG. 4. It is a graph which shows the correlation of the power generation efficiency of a generator with respect to the parameter ratio of a two-phase flow turbine. It is a second modification of FIG. It is a block diagram which shows the whole structure of the refrigeration cycle system which concerns on a prerequisite technique.

Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described as embodiments or shown in the drawings are not intended to limit the scope of the present invention to this, but are merely explanatory examples. do not have.

<Prerequisite technology>
First, the prerequisite technique of the refrigeration cycle system according to at least one embodiment of the present invention will be described. FIG. 10 is a block diagram showing the overall configuration of the refrigeration cycle system 10 ′ according to the prerequisite technique. The refrigeration cycle system 10'is an air conditioning system using a refrigeration cycle. In the following description, the state in which the refrigeration cycle system 10'is operated in the cooling cycle will be described, but unless otherwise specified, the present invention can be applied to the state in which the refrigeration cycle system 10'is operated in the heating cycle.

The refrigeration cycle system 10'contains typically two refrigeration cycles (first refrigeration cycle 10A and second refrigeration cycle 10B) consisting of a compression step, a condensation step, an expansion step and an evaporation step. Each of the first refrigeration cycle 10A and the second refrigeration cycle 10B is configured by arranging a compressor, a condenser, an expansion valve and an evaporator corresponding to each process on the circulation path through which the refrigerant flows, and is independent of each other. is doing.

In the first refrigeration cycle 10A, the first compressor 14A, the first condenser 16A, the first upstream expansion valve 18A, the first gas-liquid separator 20A, the first downstream expansion valve 22A, and the first are on the circulation path 12A. 1 Evaporators 24A are arranged in order. The first compressor 14A is a multi-stage type and includes a first low pressure side compressor 14A1 and a first high pressure side compressor 14A2 arranged in series along the circulation path 12A. The first low-pressure side compressor 14A1 and the first high-pressure side compressor 14A2 are coaxially connected to each other and are configured to be driveable by a motor 26A.

The high-temperature and high-pressure refrigerant discharged from the first compressor 14A is sent to the first condenser 16A and condensed by heat exchange with the outside air. The refrigerant condensed in the first condenser 16A is decompressed by the first upstream expansion valve 18A, and then gas-liquid separated by the first gas-liquid separator 20A. A part of the gas phase component separated by the first gas-liquid separator 20A is recompressed by being returned to the first high-pressure side compressor 14A2 via the return line 28A, and the rest is the first together with the liquid phase component. The pressure is further reduced by the downstream expansion valve 22A.

The refrigerant discharged from the first downstream expansion valve 22A is supplied to the first evaporator 24A. In the first evaporator 24A, the cooling water is cooled by generating cold heat by the heat of vaporization of the refrigerant by exchanging heat between the refrigerant and the cooling water. The refrigerant that has completed heat exchange in the first evaporator 24A is returned to the first compressor 14A, and the above cycle is repeated.

The second refrigeration cycle 10B has a second compressor 14B, a second condenser 16B, a second upstream expansion valve 18B, a second gas-liquid separator 20B, a second downstream expansion valve 22B, and a second on the circulation path 12B. 2 Evaporators 24B are arranged in order. The second compressor 14B is a multi-stage type and includes a second low pressure side compressor 14B1 and a second high pressure side compressor 14B2 arranged in series along the circulation path 12B. The second low-pressure side compressor 14B1 and the second high-pressure side compressor 14B2 are coaxially connected to each other and can be driven by the electric motor 26B.

The high-temperature and high-pressure refrigerant discharged from the second compressor 14B is sent to the second condenser 16B and is condensed by heat exchange with the outside air. The refrigerant condensed in the second condenser 16B is decompressed by the second upstream expansion valve 18B, and then gas-liquid separated by the second gas-liquid separator 20B. A part of the gas phase component separated by the second gas-liquid separator 20B is recompressed by being returned to the second high-pressure side compressor 14B2 via the return line 28B, and the rest is second together with the liquid phase component. The pressure is further reduced by the downstream expansion valve 22B.

The refrigerant discharged from the second downstream expansion valve 22B is supplied to the second evaporator 24B. In the second evaporator 24B, the cooling water is cooled by generating cold heat by the heat of vaporization of the refrigerant by exchanging heat between the refrigerant and the cooling water. The refrigerant that has completed heat exchange in the second evaporator 24B is returned to the second compressor 14B, and the above cycle is repeated.

It should be noted that these two refrigeration cycles (first refrigeration cycle 10A and second refrigeration cycle 10B) are in a state at each point of the circulation paths 12A and 12B according to the amount of cooling heat supplied to the cooling water to be heat exchanged. The amount (pressure, temperature, etc.) is set. In FIG. 10, the first evaporator 24A and the second evaporator 24B are arranged in series with respect to the flow direction of the cooling water, and in particular, the first evaporator 24A is arranged on the downstream side of the second evaporator 24B. Has been done.

The refrigerants handled in the first refrigeration cycle 10A and the second refrigeration cycle 10B are the same, and for example, R134a, R1233ZDE, R1234ZE, and the like are used.

Here, in the above-mentioned refrigeration cycle system 10', in order to improve the system efficiency, it is conceivable to introduce a two-phase flow turbine for each of the expansion steps of the first refrigeration cycle 10A and the second refrigeration cycle 10B. In this case, two-phase flow turbines are required for the number of refrigeration cycles (that is, "2") included in the refrigeration cycle system 10'. Due to the high cost of two-phase flow turbines, such systems are disadvantageous in terms of profitability and there is a limit to the improvement of system efficiency. Such a problem can be solved by the embodiment described below.

<Refrigeration cycle system>
FIG. 1 is a configuration diagram showing an overall configuration of a refrigeration cycle system 10 according to at least one embodiment of the present invention. In the following description, common reference numerals will be given to the configurations corresponding to the above-mentioned prerequisite techniques, and duplicate description will be omitted unless otherwise specified.

The first refrigeration cycle 10A and the second refrigeration cycle 12 included in the refrigeration cycle system 10 have the same configurations regarding the compression step, the condensation step, and the evaporation step as the above-mentioned premise techniques, but the configurations regarding the expansion step are different. That is, it is possible to improve to the following embodiments by changing the configuration related to the expansion process for the prerequisite technique.

The refrigeration cycle system 10 is a two-phase drive that can be driven by expanding the refrigerant discharged from the first condenser 16A constituting the first refrigeration cycle 10A and the second condenser 16B constituting the second refrigeration cycle 10B. A flow turbine 30 is provided. The two-phase flow turbine 30 has a turbine blade 52 (see FIG. 2) due to the expansion energy generated when the two-phase flow refrigerant in the gas-liquid mixed state condensed in the first condenser 16A and the second condenser 16B is depressurized. ) Is driven. The turbine blade 52 generates electric energy by driving a generator 34 mechanically connected to the rotating shaft 32 via the rotating shaft 32. In this way, the two-phase flow turbine 30 recovers the expansion energy generated in the expansion step as electrical energy.

The electric energy generated by the generator 34 may be stored in a power storage device such as a battery (not shown), or may be directly supplied to a load that consumes the electric energy.

As described above, in the refrigeration cycle system 10, at least a part of the expansion stroke in the first refrigeration cycle 10A and the second refrigeration cycle 10B is carried out by the common two-phase flow turbine 30. Thereby, the expansion energy generated in the expansion stroke in each of the first refrigeration cycle 10A and the second refrigeration cycle 10B can be recovered by the single two-phase flow turbine 30, and good system efficiency can be achieved. Further, since the two-phase flow turbine 30 is provided in common to the first refrigeration cycle 10A and the second refrigeration cycle 10B, the case where the two-phase flow turbine is provided for each of the first refrigeration cycle 10A and the second refrigeration cycle 10B, respectively. Compared to the above, good system efficiency can be obtained while keeping costs down.

A gas-liquid separator 36 is provided on the downstream side of the two-phase flow turbine 30. In the prerequisite technique, the first gas-liquid separator 20A and the second gas-liquid separator 20B are provided for the first refrigeration cycle 10A and the second refrigeration cycle 10B, but in the present embodiment, a common two-phase flow is provided. By providing the gas-liquid separator 36 on the downstream side of the turbine 30, it is possible to suppress the complexity and size of the system configuration.

The refrigerant discharged from the gas-liquid separator 36 passes through the first distribution flow paths 38A and 38B to the first evaporator 24A of the first refrigeration cycle 10A and the second evaporator 24B of the second refrigeration cycle 10B. Each is supplied. As a result, the refrigerant that has passed through the two-phase flow turbine 30 and the gas-liquid separator 36 that are common to the two refrigeration cycles is distributed to the two refrigeration cycles 10A and 10B via the first distribution channels 38A and 38B.

In the first distribution flow paths 38A and 38B, the first expansion valve 40A provided between the two-phase flow turbine 30 and the first evaporator 24A, and between the two-phase flow turbine and the second evaporator 24B. The provided second expansion valve 40B and the provided second expansion valve 40B are provided respectively. That is, the refrigerant discharged from the two-phase flow turbine 30 is further depressurized by the first expansion valve 40A and the second expansion valve 40B provided in the first distribution flow paths 38A and 38B, and then the first evaporator 24A and It is distributed to the second evaporator 24B. In other words, in the present embodiment, in the above-mentioned prerequisite technique (see FIG. 10), the first upstream expansion valve 18A and the second upstream expansion valve 18B are replaced with the two-phase flow turbine 30, and the first downstream expansion valve 22A is used. The second downstream expansion valve 22B is left as the first expansion valve 40A and the second expansion valve 40B. In such a configuration, since the two-phase flow turbine 30 is provided on the upstream side of the first expansion valve 40A and the second expansion valve 40B, expansion energy can be recovered in a region where the heat drop is large, and good system efficiency is achieved. can.

The distribution flow rate of the refrigerant with respect to the first refrigeration cycle 10A and the second refrigeration cycle 10B by the first distribution flow paths 38A and 38B is, for example, the first expansion valve 40A and the second expansion valve provided on the first distribution flow path 38. It may be carried out by adjusting the opening degree of 40B respectively. As a result, the refrigerant whose energy has been recovered by the two-phase flow turbine 30 can be distributed at a flow rate suitable for the first refrigeration cycle 10A and the second refrigeration cycle 10B, so that better system efficiency can be achieved. In particular, even when the prerequisite technology is modified to introduce the two-phase flow turbine 30, by appropriately adjusting the opening degrees of the first expansion valve 40A and the second expansion valve 40B, each cycle can be entered. The distribution ratio of can be easily optimized. This makes it possible to easily repair the existing system corresponding to the prerequisite technology by introducing the two-phase flow turbine 30.

Further, the refrigeration cycle system 10 is configured to supply the gas phase components of the refrigerant separated by the gas-liquid separator 36 to the first compressor 14A and the second compressor 14B, respectively, in the second distribution flow paths 42A and 42B. To prepare for. The refrigerant after energy recovery discharged from the two-phase flow turbine 30 contains a gas phase component and a liquid phase component, and these are separated by the gas-liquid separator 36. Then, the gas phase component separated by the gas-liquid separator 36 is returned to the first compressor 14A and the second compressor 14B of each refrigeration cycle via the second distribution flow paths 42A and 42B. This makes it possible to recompress and condense the vapor phase components that do not contribute to the heat of vaporization in the first evaporator 24A and the second evaporator 24B, and the system efficiency can be further improved.

<Two-phase flow turbine>
Subsequently, a specific configuration of the two-phase flow turbine 30 used in the refrigeration cycle system 10 will be described. FIG. 2 is an axial sectional view of the two-phase flow turbine 30 of FIG. 1, and FIG. 3 is a schematic view showing a first nozzle chamber 54A and a second nozzle chamber 54B in the axial vertical plane of FIG.
In the following, when the terms "circumferential direction", "axial direction", and "diametrical direction" are simply described, they mean the circumferential direction, the axial direction, and the radial direction of the two-phase flow turbine 30, respectively.

The two-phase flow turbine 30 is provided on a rotating shaft 50 extending along the axial direction, a plurality of turbine moving blades 52 arranged along the circumferential direction on the rotating shaft 50, and an upstream side of the turbine moving blade 52. It includes a first nozzle chamber 54A and a second nozzle chamber 54B, and a turbine diffuser 56 provided on the downstream side of the turbine moving blade 52.

As described above, the two-phase flow turbine 30 is introduced with condensed refrigerants from the first refrigeration cycle 10A (first condenser) and the second refrigeration cycle 10B (second condenser), respectively. The refrigerant introduced from the first refrigerant cycle 10A (first condenser 16A) is supplied to the turbine blade 52 via the first nozzle chamber 54A. The refrigerant introduced from the second refrigerant cycle 10B (second condenser 16B) is supplied to the turbine blade 52 via the second nozzle chamber 54B.

As shown in FIG. 3, the first nozzle chamber 54A and the second nozzle chamber 54B are arranged at different positions along the circumferential direction around the rotation shaft 50 and are separated from each other. As a result, even when there is a pressure difference between the refrigerants introduced from the first condenser 16A and the second condenser 16B into the two-phase flow turbine 30, energy loss is suppressed to a low level and efficient power recovery is performed. be able to.

The first nozzle chamber 54A includes at least one first turbine nozzle 58A configured to supply the refrigerant flowing in from the first condenser 16A to the turbine blades 52. The second nozzle chamber 54B includes at least one second turbine nozzle 58B configured to supply the refrigerant flowing in from the second condenser 16B to the turbine blade 52.

Here, FIG. 4 is a schematic view showing an example of the first turbine nozzle 58A and the second turbine nozzle 58B provided in the first nozzle chamber 54A and the second nozzle chamber 54B of FIG. In this embodiment, a case where a plurality of first turbine nozzles 58A and second turbine nozzles 58B are provided in the first nozzle chamber 54A and the second nozzle chamber 54B, respectively, will be described, but the first turbine nozzle 58A and the second turbine The number of nozzles 58B may be the same or different.

The first turbine nozzle 58A and the second turbine nozzle 58B are tapered-wide divergent nozzles. Such a tapered-wide divergent nozzle is, for example, a reamer nozzle formed by reamer processing. FIG. 5 is a schematic diagram showing the flow of a two-phase flow refrigerant in a tapered-sue wide nozzle. As shown in FIG. 5, the tapered-wide end nozzle has an inner diameter gradually decreasing from the nozzle inlet portion 60a having an inner diameter D1 toward the throat portion 60b, has a minimum diameter D2 in the throat portion 60b, and has a throat portion 60b. The inner diameter is configured to gradually increase toward the nozzle outlet portion 60c having the inner diameter D3 (that is, D1> D2 and D2 <D3).

The liquid phase refrigerant condensed from the first condenser 16A or the second condenser 16B is supplied to the nozzle inlet portion 60a. The refrigerant introduced into the nozzle inlet portion 60a is compressed toward the throat portion 60b and flushed in the throat portion 60b to form a two-phase flow of a gas phase and a liquid phase. The two-phase flow contains the droplet 64 in the gas 62. Since the droplet 64 is heavier than the gas 62, the flow velocity of the liquid 64 is smaller than the flow velocity of the gas 62 (for example, the flow velocity of the gas 62 is about 10 times the flow velocity of the liquid 64). The liquid 64 is accelerated by the high-speed gas 62 existing around the throat portion 60b to the nozzle outlet portion 60c. At the nozzle outlet 60c, a two-phase flow containing the accelerated droplet 64 is discharged toward the turbine blade. The two-phase flow discharged from the nozzle outlet portion 60c drives the turbine blade, and at this time, the accelerated droplet 64 mainly contained in the two-phase flow gives kinetic energy to the turbine blade. Become.

In the present embodiment, as described above, the first nozzle chamber 54A and the second nozzle chamber 54B are supplied with refrigerants having different pressures from the first refrigeration cycle 10A and the second refrigeration cycle 10B, and in particular, the first nozzle chamber. A high-pressure refrigerant is supplied to 54A from the second nozzle chamber 54B. The first turbine nozzle 58A and the second turbine nozzle 58B have different nozzle shapes depending on the pressure. Specifically, in the first turbine nozzle 58A and the second turbine nozzle 58B, the flow path of the throat portion 60b becomes smaller as the pressure ratio P3 / P1 of the pressure P1 at the nozzle inlet portion 60a and the pressure P3 at the nozzle outlet portion 60c becomes smaller. It is formed so that the area expansion ratio ρ3 / ρ2 of the flow path area ρ3 of the nozzle outlet portion 60c with respect to the area ρ2 becomes smaller. As a result, the expansion of the working fluid on the low pressure cycle side in the nozzle can be optimized and the droplet acceleration in the nozzle can be promoted, so that the turbine blade 52 can be driven more efficiently.

Further, the first turbine nozzle 58A and the second turbine nozzle 58B may be formed so that the length L from the throat portion 60b to the nozzle outlet portion 60c increases as the pressure P1 at the nozzle inlet portion 60a decreases.

As described above with reference to FIG. 5, in the tapered-wide end nozzle, the droplet 64 generated in the throat portion 60b is a high-speed gas in the range of length L between the throat portion 60b and the nozzle outlet portion 60c. Accelerated by 62. Therefore, when the inlet pressure of the turbine nozzle is small, the flow velocity of the droplet (liquid phase component) contained in the two-phase flow is relatively slow, so by designing the nozzle length to be large, a large acceleration section can be secured. The flow velocity at the nozzle outlet portion 60c can be increased.

FIG. 6 is a modification of FIG. 4, but since a refrigerant having a pressure higher than that of the second turbine nozzle 58B is supplied to the first turbine nozzle 58A, in this modification, the length L2 of the second turbine nozzle 58B is , The length of the first turbine nozzle 58A is set to be larger than the length L1. As a result, the turbine blade 52 can be driven more efficiently.

<First modification>
FIG. 7 is a first modification of FIG. 4. In this modification, the first flow rate control valve 60A and the second flow rate control valve 60B are provided at the nozzle inlet portions 60a of the first nozzle chamber 54A and the second nozzle chamber 54B, respectively. The first flow rate control valve 60A and the second flow rate control valve 60B are configured to be able to control the flow rate of the refrigerant with respect to the first nozzle chamber 54A and the second nozzle chamber 54B by adjusting the opening degree.
The control of the first flow rate control valve 60A and the second flow rate control valve 60B may be manually performed by the operator, or may be automatically performed by using an electronic arithmetic unit such as a computer. May be good.

Here, FIG. 8 is a graph showing the correlation of the power generation efficiency η of the generator with respect to the parameter ratio U / C0 of the two-phase flow turbine 30. Here, U is the rotational peripheral speed (m / s) of the two-phase flow turbine 30, C0 indicates the theoretical speed at the turbine inlet (nozzle inlet) and the turbine outlet (rotor blade outlet), and C0 is the turbine pressure ratio. Correlate. The turbine pressure ratio is defined by the pressure ratio at the turbine outlet to the turbine inlet. In the present embodiment, the pressure P1 (see FIG. 5) at the nozzle inlet portion 60a of the first nozzle chamber 54A or the second nozzle chamber 54B corresponds to the pressure at the turbine inlet portion. Strictly speaking, the pressure at the turbine outlet is the outlet pressure of the turbine blade 52, but in the present embodiment, it is simply regarded as equivalent to the pressure P3 (see FIG. 5) at the nozzle outlet 60c. Therefore, the turbine pressure ratio is defined by the ratio P1 / P3 of the nozzle inlet pressure P1 to the nozzle outlet pressure P3. As shown in FIG. 8, the efficiency η has a maximum value at a specific parameter ratio U / C0, and it is shown that the efficiency η tends to decrease when the operating state of the two-phase flow turbine 30 deviates from the optimum value. ..

In this modification, the opening degree of the first flow rate control valve 60A and the second flow rate control valve 60B is controlled so that the parameter ratio U / C0 is within a predetermined range including the maximum value of the efficiency η. In the example of FIG. 8, the control range R of the parameter ratio U / C0 is shown by hatching. As a result, even when the operating state of the refrigeration cycle system 10 changes, such as in partial load operation, a predetermined system efficiency is ensured. That is, robust system performance can be obtained for partial loads.

<Modification 2>
FIG. 9 is a second modification of FIG. In the first modification (FIG. 7), the first flow rate control valve 60A and the second flow rate control valve 60B are provided for the first nozzle chamber 54A and the second nozzle chamber 54B, but in the second modification, they are provided. , As shown in FIG. 9, may be provided for each of the first turbine nozzle 58A and the second turbine nozzle 58B. That is, the first flow rate control valve 60A and the second flow rate control valve 60B are individually provided for the first turbine nozzle 58A and the second turbine nozzle 58B included in the first nozzle chamber 54A and the second nozzle chamber 54B. May be good.

Also in the second modification, similarly to the first modification described above, in the first flow rate control valve 60A and the second flow rate control valve 60B, the parameter ratio U / C0 is within a predetermined range including the maximum value of the efficiency η. The opening is controlled. In the second modification, since the first flow rate control valve 60A and the second flow rate control valve 60B are individually provided for the first turbine nozzle 58A and the second turbine nozzle 58B, the flow rate of the refrigerant is provided for each turbine nozzle. Can be finely adjusted. Therefore, the opening degree can be controlled more accurately so that the parameter ratio U / C0 is within a predetermined range including the maximum value of the efficiency η as compared with the first modification.

In the second modification, since it is necessary to connect the first flow rate control valve 60A and the second flow rate control valve 60B to the first turbine nozzle 58A and the second turbine nozzle 58B, the first turbine nozzle 58A and the second turbine nozzle 58B The second turbine nozzle 58B can be easily realized by using, for example, a reamer nozzle that can be easily connected mechanically. Of course, it is obvious that the first turbine nozzle 58A and the second turbine nozzle 58B can take other aspects of the reamer nozzle.

As described above, according to at least one embodiment of the present invention, it is possible to provide a refrigeration cycle system capable of achieving good system efficiency by recovering the expansion energy of the refrigerant in the refrigeration cycle using a low cost configuration.

At least one embodiment of the present invention can be used in a refrigeration cycle system capable of recovering expansion energy during the expansion stroke of the refrigeration cycle.

10 Refrigeration Cycle System 10A 1st Refrigeration Cycle 10B 2nd Refrigeration Cycle 12A, 12B Circulation Path 14A 1st Compressor 14B 2nd Compressor 16A 1st Condenser 16B 2nd Condenser 24A 1st Evaporator 24B 2nd Evaporator 26A , 26B Electric motor 30 Two-phase flow turbine 34 Generator 36 Gas-liquid separator 38A, 38B First distribution flow path 40A First expansion valve 40B Second expansion valve 42A, 42B Second distribution flow path 52 Turbine drive blade 54A First nozzle Room 54B 2nd nozzle room 58A 1st turbine nozzle 58B 2nd turbine nozzle 60A 1st flow control valve 60B 2nd flow control valve 60a Nozzle inlet 60b Throat 60c Nozzle outlet

Claims (12)

Includes a first compressor that compresses the refrigerant, a first condenser that condenses the refrigerant discharged from the first compressor, and a first evaporator that vaporizes the refrigerant discharged from the first condenser. The first refrigeration cycle and
A second compressor that compresses the refrigerant, a second condenser that condenses the refrigerant discharged from the second compressor, and a second evaporator that vaporizes the refrigerant discharged from the second condenser. Including the second refrigeration cycle and
A two-phase flow turbine that can be driven by expanding the refrigerant discharged from the first condenser and the second condenser.
A power generation device mechanically connected to the two-phase flow turbine,
A first distribution flow path configured to supply the refrigerant discharged from the two-phase flow turbine to the first compressor and the second compressor, respectively.
Equipped with a refrigeration cycle system. The first distribution flow path is
A first expansion valve provided between the two-phase flow turbine and the first evaporator,
A second expansion valve provided between the two-phase flow turbine and the second evaporator,
The refrigeration cycle system according to claim 1. By adjusting the opening degree of each of the first expansion valve and the second expansion valve, the distribution ratio of the refrigerant to the first refrigeration cycle and the second refrigeration cycle can be adjusted from the two-phase flow turbine. The refrigeration cycle system according to claim 2. A gas-liquid separator provided on the downstream side of the two-phase flow turbine,
A second distribution flow path configured to supply the gas phase component of the refrigerant separated by the brackish water separator to the first compressor and the second compressor, respectively.
The refrigeration cycle system according to any one of claims 1 to 3. The two-phase flow turbine is
A first nozzle chamber including at least one first turbine nozzle configured to supply the refrigerant flowing from the first condenser to the turbine blades.
A second nozzle chamber including at least one second turbine nozzle configured to supply the refrigerant flowing from the second condenser to the turbine blades.
Equipped with
The refrigeration cycle system according to any one of claims 1 to 4, wherein the first nozzle chamber and the second nozzle chamber are separated from each other. The refrigeration cycle system according to claim 5, wherein the first turbine nozzle and the second turbine nozzle are tapered-wide-end nozzles. The first turbine nozzle and the second turbine nozzle are formed so that the area expansion ratio of the outlet area with respect to the throat area decreases as the pressure ratio of the nozzle inlet pressure and the nozzle outlet pressure decreases. The refrigeration cycle system described. The refrigeration cycle according to claim 6 or 7, wherein the first turbine nozzle and the second turbine nozzle are formed so that the length from the throat portion to the nozzle outlet portion increases as the nozzle inlet pressure decreases. system. A first flow rate control valve for adjusting the flow rate of the refrigerant with respect to the first nozzle chamber,
A second flow rate control valve for adjusting the flow rate of the refrigerant with respect to the second nozzle chamber,
Equipped with
In the first flow rate control valve and the second flow rate control valve, the ratio U / C0 of the rotational peripheral speed U of the two-phase flow turbine and the theoretical speed C0 of the nozzle inlet pressure and the turbine outlet pressure is within a predetermined range. The refrigeration cycle system according to any one of claims 5 to 8, which is controlled in such a manner. The first flow rate control valve is provided in the first nozzle chamber including the plurality of the first turbine nozzles.
The refrigeration cycle system according to claim 9, wherein the second flow rate control valve is provided in the second nozzle chamber including the plurality of the second turbine nozzles. The first flow rate control valve is provided in each of the plurality of first turbine nozzles.
The refrigeration cycle system according to claim 9, wherein the second flow rate control valve is provided in each of the plurality of second turbine nozzles. The refrigeration cycle system according to claim 11, wherein the first turbine nozzle and the second turbine nozzle are reamer nozzles.

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