JP2021195888A - Waste heat recovery system and composite scroll fluid machine used therefor - Google Patents

Abstract

To provide a waste heat recovery system capable of simply forming an expander configuring a part of a Rankine cycle and a compressor configuring a part of a refrigeration cycle, by a pressure cancelling type scroll fluid machine, and to provide a composite fluid machine used for the waste heat recovery system.SOLUTION: An expander of a Rankine cycle 6 is configured by a first scroll fluid machine 3A, and a compressor of a refrigeration cycle 10 is configured by a second scroll fluid machine 3B having the same structure as the first scroll fluid machine 3A. The first scroll fluid machine 3A and the second scroll fluid machine 3B are joined back-to-back through a coupling housing 3C. A coupling shaft 30A of the first scroll fluid machine 3A is coupled and fixed with a coupling shaft 30B of the second scroll fluid machine 3B in the coupling housing 3C to configure a composite fluid machine 3.SELECTED DRAWING: Figure 1

Description

The present invention relates to a waste heat recovery system that recovers low-temperature waste heat such as engine waste heat and factory waste heat and drives a refrigeration cycle using the recovered waste heat as a power source, and is used in the waste heat recovery system. Related to compound scroll fluid machines.

The exhaust heat recovery device disclosed in Patent Document 1 (Japanese Patent No. 6674796) is a flow path from an inlet to an outlet, and is a first type that sucks air from the mouth, compresses it, and discharges it to the outlet. A compressor, a first heat exchanger that recovers heat from the compressed air downstream of the first compressor, and a second heat exchanger that recovers heat from the compressed air downstream of the first heat exchanger. Driven by the first heat exchanger that evaporates the refrigerant by heat exchange with the compressed air, and the refrigerant that evaporates in the first heat exchanger. An expander is provided, a first condenser that condenses the refrigerant exhausted from the expander, and a pump that supplies the refrigerant condensed by the first condenser to the first heat exchanger. The second heat exchange that evaporates the refrigerant by heat exchange with the compressed air in the Rankin cycle flow path and the circulation flow path in which a refrigerant of the same type as the refrigerant flowing in the Rankin cycle flow path flows. A second compressor that is rotationally driven by the rotational driving force obtained by the device and the expander and compresses the refrigerant evaporated by the second heat exchanger, and the refrigerant discharged from the second compressor. It is provided with a second condenser for condensing heat and a refrigerating cycle flow path provided with an expansion valve for expanding the refrigerant condensed by the second condenser.

According to this configuration, the exhaust heat of the compressor of the air flow path can be effectively used in the first heat exchanger of the Rankin cycle flow path and the second heat exchanger of the refrigeration cycle flow path. The rotational driving force generated by the inflator can be used as the rotational driving force of the second compressor in the refrigeration cycle flow path to reduce the driving power of the second compressor and save energy. At this time, it was generated in the inflator. It is disclosed that since the second compressor is directly rotationally driven without converting the rotational driving force into electricity or the like, there is no energy loss associated with the electric conversion or the like.

The waste heat utilization device disclosed in Patent Document 2 (Japanese Unexamined Patent Publication No. 2011-214484) uses a drive source, a rotary electric machine functioning at least as a generator, and a refrigerant for a Rankin cycle to drive a shaft of the rotary electric machine. A connection state in which an expander that applies a rotational force to a compressor, a compressor that sucks in and discharges a refrigerating cycle refrigerant, and a drive shaft and a rotary shaft of the compressor are connected, or a drive shaft and the rotary shaft. A composite fluid machine equipped with a switching means for switching to a cutting state constitutes each part of the Rankin cycle circuit and the refrigerating cycle filter, and the region where the Rankin cycle refrigerant exists and the region where the refrigerating cycle refrigerant exists. The rotor of the rotary electric machine utilizes the waste heat of the drive source in the region where the refrigerating cycle refrigerant exists in the composite fluid machine. The composite fluid machine of this waste heat utilization device has an entire housing consisting of a center housing, a front housing, and a rear housing. A motor genierator is arranged in the center housing, and a scroll type is provided in the front housing. A compressor is provided, and a scroll-type inflator is provided in the rear housing.

The vehicle waste heat recovery system disclosed in Patent Document 3 (Japanese Unexamined Patent Publication No. 2019-12064) uses a heater that heats the working fluid by utilizing the waste heat of the engine and a working fluid that has passed through the heater. An expander that expands to generate power, a Rankin condenser that condenses the working fluid that has passed through the expander, and a working fluid pump that sends the working fluid that has passed through the Rankin condenser to the heater in sequence. A Rankin cycle system having an arranged Rankin cycle circuit, an engine cooling water system having an engine cooling water circuit in which cooling water circulates through a pump via the heater and the engine, and a compressor for compressing a refrigerant. A heat exchanger that dissipates heat from the refrigerant compressed by the compressor, a decompression device that depressurizes after heat is exchanged with the outside air by the heat exchanger, and an evaporator that heats the decompressed refrigerant are sequentially arranged. The heat exchanger is a heat exchanger that exchanges heat between the cooling water flowing through the engine cooling water circuit and the refrigerant flowing through the refrigerant cycle circuit. It is arranged between the heater and the engine in the engine cooling water circuit.

Japanese Patent No. 6674796 Japanese Unexamined Patent Publication No. 2011-214484 Japanese Unexamined Patent Publication No. 2019-12164

A Rankine cycle that obtains driving force by using waste heat generated from an internal combustion engine such as an engine or factory waste heat, and a refrigeration cycle that uses the driving force obtained by this Rankine cycle to drive a compressor in a refrigeration cycle. It is known from Patent Documents 1 to 3 that the provision is provided.

In Patent Document 1, since the expander and the compressor are fluidly connected in the casing, the second compressor can be rotationally driven by the rotational driving force obtained when the refrigerant is expanded by the expander. Therefore, it has the effect of reducing the driving power of the second compressor and saving energy, and also because the rotational driving force generated by the expander is not changed to electricity or the like and the second compressor is directly rotationally driven. It has the effect that there is no energy loss due to electrical conversion, etc., but it prevents the mixing of the refrigerant between the expander of the Rankin cycle flow path and the second compressor of the refrigeration cycle flow path, and prevents the expander and the second compressor. It has the drawback that the same type of refrigerant must be used in order to eliminate the need for a seal between the compressor and the compressor. Further, in Patent Document 1, since the inflator and the second compressor are both screw type, the suction side and the discharge side of the inflator and the second compressor are both the central portion of the housing. Since it is necessary to form a discharge flow path in the housing, there is a problem that it is difficult to form a discharge flow path.

In the composite fluid machine disclosed in Patent Document 2, a motor generator is arranged in the center of the center housing, functions as an electric motor that rotates the rotor by energizing the coil of the stator, and power is supplied to the coil by rotating the rotor. It also has a function as a generator to generate, and a scroll type compressor is provided between the support block provided in the front part of the center housing and the front housing, and a side plate is provided in the rear part of the center housing. Is fixed to face the bulkhead, a pump chamber is partitioned between the bulkhead and the side plate, and a scroll-type inflator is placed between the support block provided in the rear of the center housing and the rear housing. Is provided. As described above, in the present invention, the compression chamber, the electromagnetic clutch, the motor generator, the gear pump, and the expander are arranged in this order from the front housing to the rear housing in the entire housing, and the structure is long in the axial direction. The structure itself is complicated.

The vehicle waste heat recovery system described in Patent Document 3 includes a Rankine cycle system, an engine cooling water system, and a refrigeration cycle system, and includes an expander and a part of the refrigeration cycle that form a part of the Rankine cycle. It is configured as a device independent of the compressors that make up the above.

As mentioned above, it is known that the waste heat recovery system is composed of a Rankine cycle and a refrigeration cycle, and further, an expander constituting a part of the Rankine cycle and a compressor constituting a part of the refrigeration cycle. It is already known that the inflator and the compressor are configured by a scroll fluid machine.

However, providing the scroll fluid portion as an expander and the scroll fluid portion as a compressor in the same housing complicates the structure. In the waste heat recovery system described above, it is difficult to easily and inexpensively form a composite fluid machine in which a scroll type expander and a compressor are integrally configured.

Further, in a scroll fluid machine, the compressed space expands from the center to the outer peripheral direction to become an expander, and the compressed space shrinks from the outer peripheral direction to the center to become a compressor, so that the rotation direction of the drive shaft is changed in a sense. Thereby, a normal scroll fluid machine can be both an expander and a compressor. However, the conventional swivel scroll compressor has a discharge pressure on the back surface of the swivel scroll in order to reduce the axial gas force (pulling force) that tries to separate both scrolls in the main axis direction by the compression action of the fixed scroll and the swivel scroll. A pressure intermediate between the suction pressure and the suction pressure is introduced to generate an attractive force that cancels the pulling force. However, since this intermediate pressure is a value proportional to the suction pressure, when the rotation speed is different or the pressure is different, the back pressure becomes excessive or insufficient and the thrust force between the turning scroll and the fixed scroll changes. However, if the sliding friction of the tooth tip and the tooth bottom of each lap increases, the mechanical efficiency decreases, and if the gap is too large, the performance decreases. In addition, since it is necessary to equip the discharge part with a check valve, injection port, release hole, etc. in the compressor, it is difficult to easily convert the same compressor to an expander. In reality, the compressor and the compressor are compressed. The reality is that the machine is specially designed.

On the other hand, the pressure canceling type scroll fluid machine has an advantage that the pressure balance adjustment is not required at all because the pulling force in the axial direction is not generated at all. Therefore, in constructing a composite fluid machine that integrates an expander that constitutes a part of the Rankin cycle and a compressor that constitutes a part of the refrigeration cycle, a pressure-canceling scroll fluid machine is used. The present inventor has found that the same main body can be used as both an expander and a compressor. Thereby, the present invention constitutes a composite fluid machine by coupling a pair of pressure-canceling scroll fluid machines back to back, and a compressor placed on one side of the composite fluid machine by an expander placed on the other. It is an object of the present invention to provide a simple and low-cost waste heat recovery system for driving a fluid system.

Therefore, the present invention uses a Rankin evaporator that exchanges heat with a first heat exchange medium that moves from a heat source and evaporates a second heat exchange medium, and a second heat exchange medium that evaporates with the Rankin evaporator. An inflator, a Rankin condenser that condenses a second heat exchange medium expanded by the expander, and a pump that supplies a second heat exchange medium condensed by the Rankin condenser to the Rankin evaporator. By a Rankin cycle composed of, a condenser for a refrigerating cycle for condensing a third heat exchange medium, an expansion means for adiabatic expansion of a third heat exchange medium condensed by the condenser for a refrigeration cycle, and the expansion means. A waste heat recovery system consisting of a refrigerating cycle evaporator for evaporating an expanded third heat exchange medium and a refrigerating cycle composed of a compressor for compressing a third heat exchange medium evaporated by the refrigerating cycle evaporator. The expander is a pressure-canceling first scroll fluid machine, and the compressor is a pressure-canceling second scroll fluid machine having the same structure as the first scroll fluid machine. The scroll fluid machine 1 and the second scroll fluid machine are back-to-back coupled via a connecting housing, and the connecting shaft of the first scroll fluid machine is connected to the connecting shaft of the second scroll fluid machine. It is to form a composite fluid machine by being connected and fixed in a housing.

With the above configuration, the first heat exchange medium supplied from the heat source and the second heat exchange medium that has been heat-exchanged and evaporated in the Rankin evaporator expand adiabatically and expand with the expansion energy when passing through the expander. Rotate the connecting shaft. Since this rotational force rotates the connecting shaft of the compressor, the third heat exchange medium circulating in the refrigeration cycle is compressed, and the third heat exchange medium circulates in the refrigeration cycle. In this way, the heat source, for example, low-temperature waste heat such as engine waste heat and factory waste heat can be recovered and used as a drive source for driving the refrigeration cycle.

Further, in the Rankine cycle of the waste heat recovery system, it is preferable to provide a heating means between the Rankine evaporator and the expander. As a result, when the refrigerator is operated by using the waste heat of the cooling water of the engine in a refrigerating truck, etc., the operation is stopped for a long time such as during a night break, or the heat source supply is stopped due to an unexpected trouble. If the heating of the second heat exchange medium by the evaporator is insufficient or stopped, the expander cannot be driven and the refrigerator must be stopped. Stopping the refrigerator is a fatal injury for the freezing truck, and some alternative operating means is required. However, since the configuration does not originally have a motor, the solution is to use an auxiliary motor when the refrigerator is stopped. Needed to be a complex configuration that could be used by. However, in the present invention, this insufficient heating can be compensated only by installing the heating means, so that the driving force of the expander can be secured with a simple configuration. As the heating means, it is desirable that the heater uses an external power source (for example, a battery, solar power generation, a fuel cell, a commercial power source, etc.). It should be noted that the structure of the compressor and the expander does not need to be particularly limited with respect to this invention alone.

Further, in the present invention, the composite fluid machine used in the waste heat recovery system having the above-described configuration is located on a substantially cylindrical side surface portion, a front end surface portion located on one side of the side surface portion, and the other side of the side surface portion. A housing consisting of a rear end face portion located, which defines an internal space and is provided with an opening for communicating the internal space with the outside, a rotation shaft rotatably supported by the front end face portion, and the rear end face. A connecting shaft rotatably supported by the portion, a first drive scroll member fixed to the rotating shaft and extending radially, and a connecting shaft fixed to the connecting shaft and extending radially. A spiral first driven scroll and a second scroll that mesh with a second drive scroll member to be output and a first drive scroll of the first drive scroll member to define a first compressed space. A spiral second driven scroll that meshes with a second drive scroll of the member to define a second compression space, and is rotatably held by the front end face portion and the rear end face portion. The first and second compression spaces are configured to gradually expand the space from the center toward the outer periphery, and the through hole provided through the rotation axis is the first. A first scroll fluid machine that communicates with the innermost peripheral ends of the first and second compressed spaces, and the outermost peripheral ends of the first and second compressed spaces communicate with the inner space, and the first scroll fluid. A second scroll fluid machine having the same configuration as the machine, wherein the connecting shaft of the second scroll fluid machine is connected to the connecting shaft of the first scroll fluid machine in the connecting housing. It consists of a scroll fluid machine. According to the pressure canceling type scroll fluid machine described above, the same compressor and expander can be easily used because the conventional axial gas force (pulling force) that tries to separate both scrolls in the main axis direction is not generated. It will be possible to use it.

Further, the first scroll fluid machine is to be used as an expander constituting a part of the Rankine cycle, and the second scroll fluid machine is to be used as a compressor forming a part of the refrigeration cycle. ..

With the above configuration, two scroll fluid machines having the same structure are arranged back to back via the connecting housing, and in the connecting housing, the connecting shaft of the first scroll fluid machine and the second scroll. A composite scroll fluid machine is constructed by connecting with the connecting shaft of the fluid machine. This makes it possible to construct a composite scroll fluid machine including an expander and a compressor connected by two scroll fluid machines having the same structure, so that the cost can be reduced.

Further, the connecting housing defines a connecting space for accommodating a connecting portion between the connecting shaft of the first scroll fluid machine and the connecting shaft of the second scroll fluid machine, and the connecting space is the second. It is preferable to communicate with the internal space of the scroll fluid machine.

As a result, the connected space in the connected housing is sealed from the outside air, and the refrigerant can be prevented from leaking to the atmosphere. Further, since the pressure is the same as that of the internal space of the second scroll fluid machine serving as the compressor, the shaft seal with the compressor can be eliminated. Further, since the pressure inside the inflator housing and the inside of the connecting housing are both low, the differential pressure becomes small, which facilitates sealing with a simple shaft seal such as a lip seal.

As described above, according to the present invention, the same main body can be used by using the same main body and connecting them in opposite directions to reverse the rotation direction, and by using a compressor and an expander, so that the same main body can be used. Reduction is possible.

It is a schematic block diagram of the waste heat recovery system which concerns on embodiment of this invention. It is a schematic block diagram of the waste heat recovery system which concerns on another Example of this invention. It is a schematic block diagram of a compound scroll fluid machine.

Hereinafter, examples of the present invention will be described with reference to the drawings.

The waste heat recovery system 1 according to the embodiment of the present invention is, for example, as shown in FIG. 1, a first heat transferred from a heat source such as an engine waste heat source (radiator or the like) or a factory waste heat source (steam after power generation). A Rankine evaporator 2 that absorbs heat from an exchange medium (for example, water) and evaporates (vaporizes) a refrigerant such as a second heat exchange medium (for example, HF01233zd or HFC245fa). The heat of the first scroll fluid machine 3A as an expander for expanding the heat exchange medium of 2 and the second heat exchange medium expanded by the first scroll fluid machine 3A is radiated to, for example, passed air and condensed ( The Rankine cycle 6 is provided with a Rankine cycle 6 composed of a Rankine condenser 4 to be liquefied) and a pump 5 for supplying a second heat exchange medium condensed by the Rankine condenser 4 to the Rankine evaporator 2. The cycle is preferably an organic Rankine cycle (ORC).

Further, the waste heat recovery system 1 is a refrigerating cycle condenser 7 and a refrigerating cycle condenser 7 that dissipate heat to the air passing through the heat of a third heat exchange medium (for example, a refrigerant such as R448A) and condense the heat. For an expansion means 8 such as an expansion valve that adiabatically expands a third heat exchange medium condensed by the above, and for a refrigeration cycle in which the third heat exchange medium expanded by the expansion means 8 absorbs and evaporates the heat of the air passing through it. Further comprising a refrigeration cycle 10 configured by an evaporator 9 and a second scroll fluid machine 3B as a compressor for compressing a third heat exchange medium evaporated by the refrigeration cycle evaporator 9.

Further, the first scroll fluid machine 3A and the second scroll fluid machine 3B are back-to-back coupled via a connecting housing 3C, and the connecting shaft 30A of the first scroll fluid machine 3A is the second scroll fluid machine. The composite fluid machine 3 is formed by connecting and fixing the connecting shaft 30B of the scroll hydraulic machine 3B and the connecting housing 3C by a coupling or the like.

With the above configuration, the first heat exchange medium that conveys waste heat from the engine and the like and the second heat exchange medium that circulates in the Rankin cycle 6 exchange heat in the Rankin evaporator 2, and the first heat is exchanged. The heat of the exchange medium causes the second heat exchange medium to evaporate (vaporize). The evaporated heat exchange medium passes through the first scroll fluid machine 3A while expanding, and rotates the connecting shaft 30A of the expander 3A. Since this rotational force rotates the connecting shaft 30B of the second scroll fluid machine 3B, the third heat exchange medium circulating in the refrigeration cycle 10 is condensed (liquefied) by the refrigeration cycle condenser 7, and the evaporator 9 is used. The refrigerant heated and evaporated in the above is sucked into the second scroll fluid machine 3B and is compressed and discharged.

As described above, in the composite fluid machine 3 in which the scroll fluid machines that also use the same main body are arranged back to back via the connecting housing 3C and the connecting shafts 30A and 30B are connected to each other, the connecting shaft 30A, When 30B is rotated in the same direction, one operates as a compressor and the other operates as an expander. As a result, the refrigerating cycle 10 can be operated by the heat recovered in the Rankin evaporator 2.

Further, in the refrigerating cycle 10, the refrigerating cycle evaporator 9 is arranged, for example, in the air flow path of the air conditioning system, absorbs the heat of the passing air, and evaporates the third heat exchange medium. It cools the passing air. In this way, the heat of the radiator of the engine or the like can be recovered to drive the refrigeration cycle.

The waste heat recovery cycle 6A shown in FIG. 2 is characterized in that a heating means 11 such as a heater is provided between the Rankin evaporator 2 and the first scroll fluid machine 3A. As a result, when the second heat exchange medium passing through the Rankin evaporator 2 is not sufficiently vaporized due to the stoppage or shortage of the heat source, the second heat exchange medium is heated by the heating means 11 and sufficiently evaporated. It can be sufficiently inflated by the first scroll fluid machine 3A.

The composite fluid machine 3 used in the waste heat recovery system 1 described above is, for example, as shown in FIG. 3, a pressure-canceling type first scroll fluid machine 3A serving as an expander and the first scroll machine serving as a compressor. It is composed of a second scroll fluid machine 3B having the same structure as the fluid machine 3A.

The first scroll fluid machine 3A that operates as an expander in the third embodiment has a substantially cylindrical side surface portion 31A, a front end surface portion 32A located on one side of the side surface portion 31A, and the other side of the side surface portion 31A. It is rotatably supported by the housing 36A and the front end face portion 32A, which are composed of the rear end face portion 33A located in the above, and are provided with an opening 35A for defining the internal space 34A and communicating the internal space 34A with the outside. The connecting shaft 37A, the connecting shaft 30A rotatably supported by the rear end face portion 33A, and the first drive scroll member 38A fixed to the rotating shaft 37A and extending radially in a spiral shape. The second drive scroll member 39A fixed to the shaft 30A and extending radially in a spiral shape and the first drive scroll 40A of the first drive scroll member 38A mesh with each other to form a first expansion space 42A. A spiral second driven scroll that meshes with a spiral first driven scroll 44A and a second drive scroll 41A of the second drive scroll member 39A to define a second expansion space 43A. 45A is provided, and a driven scroll member 46A rotatably held by the front end face portion 32A and the rear end face portion 33A is provided, and the first and second compression spaces 42A and 43A are in the outer peripheral direction from the center. The through hole 47A provided so as to penetrate the rotating shaft 37A communicates with the innermost peripheral ends of the first and second expansion spaces 42A and 43A. The outermost outermost ends of the first and second expansion spaces 42A and 43A are configured to communicate with the internal space 34A. The refrigerant heated at high pressure flows into the center of the expander through the through hole 47 and is rotationally driven while expanding the volume to generate power. Since the pressure inside the inflator has a pressure canceling mechanism, there is no need to adjust the pressure balance because there is no pulling force in the axial direction, so it is possible to use the same main body of the inflator and compressor. There is.

The second scroll fluid machine 3B that operates as a compressor in the third embodiment has a structure similar to that of the first scroll member 3A, and has a substantially cylindrical side surface portion 31B and one side of the side surface portion 31B. A housing consisting of a front end face portion 32B located in the above and a rear end face portion 33B located on the other side of the side surface portion 31B, and an opening 35B for defining the internal space 34B and communicating the internal space 34B with the outside is provided. 36B, a rotating shaft 37B rotatably supported by the front end face portion 32B, a connecting shaft 30B rotatably supported by the rear end face portion 33B, and a radial spiral fixed to the rotating shaft 37B. The first drive scroll member 38B extending to the above, the second drive scroll member 39B fixed to the connecting shaft 30B and extending radially in a radial direction, and the first of the first drive scroll member 38B. A second of the spiral first driven scroll 44B and the second drive scroll member 39B that meshes with the drive scroll 40B of the above to define a first compression space (same as the first expansion space) 42B. A spiral second driven scroll 45B that meshes with the drive scroll 41B to define a second compressed space (same as the second compressed space) 43B is provided, and the front end face portion 32B and the rear end face portion are provided. The driven scroll member 46B rotatably held in the 33B is provided, and the first and second compression spaces 42B and 43B are configured to gradually expand the space from the center toward the outer peripheral direction. A through hole 47B provided through the rotating shaft 37B communicates with the innermost peripheral end of the first and second compression spaces 42B and 43B, and is the outermost circumference of the first and second compression spaces 42B and 43B. The ends are configured to communicate with the internal space 34B. The low-temperature gaseous refrigerant is sucked from the through hole 35B, and the high-temperature and high-pressure refrigerant gas is discharged from the discharge port 47B while the volume of the compression spaces 42B and 43B is reduced toward the center by the compressor 3B. Since the generated pressure inside the compressor 3B is a pressure canceling mechanism, there is no need to adjust the pressure balance because no axial pulling force is generated, so the same main body of the expander and compressor can be used together. It has become.

As described above, the second scroll fluid machine 3B having the same configuration as the first scroll fluid machine 3A is arranged back to back with the first scroll fluid machine 3A via the connecting housing 3C. In the connecting housing 3C, the connecting shaft 30A of the first scroll fluid machine 3A and the connecting shaft 30B of the second scroll fluid machine 3B are connected and fixed. Further, the rotary shaft 37A of the first scroll fluid machine 3A and the rotary shaft 37B of the second scroll fluid machine 3B are rotatably held by the front end face portions 32A and 32B, respectively, via bearings and the like. The tip is sealed by caps 49A, 49B.

As described above, in the third embodiment, one of the composite fluid machines 3, for example, the first scroll fluid machine 3A is the composite fluid machine as an expander constituting a part of the Rankin cycle 6 (or 6A). On the other hand, for example, the second scroll fluid machine 3B is used as a compressor constituting a part of the refrigeration cycle 10.

Further, the connected housing 3C defines a connected space 3D accommodating a connecting portion between the connecting shaft 30A of the first scroll fluid machine 3A and the connecting shaft 30B of the second scroll fluid machine 3B. The connected space 3D communicates with the internal space 34B of the second scroll fluid machine 3B. In order to achieve this structure, the rear end face portions 33A and 33B of the first and second scroll fluid machines 3A and 3B are formed with communication holes 48A and 48B penetrating the rear end face portions 33A and 33B, respectively. .. In the third embodiment, since the second scroll fluid machine 3B acts as a compressor, the communication hole 48B formed in the rear end face portion 33B of the second scroll fluid machine 33B is opened, and the first scroll fluid is opened. The communication hole 48A formed in the rear end face portion 33A of the machine 33A is closed. As a result, the internal space 34B of the second scroll fluid machine 3B and the connected space 3D in the connected housing 3C are in a communicative state and have the same pressure, so that the shaft seal on the peripheral edge of the connected shaft 30B becomes unnecessary. In order to avoid mixing of a different type of refrigerant from the internal space 34A of the first scroll fluid machine 3A as an expander and the connected space 3D, a cap 50A constituting a lip seal is provided to shut off the two. Is preferable. Further, since both the internal space 34A and the connected space 3D have a low pressure, the pressure difference applied to the lip seal becomes smaller, which facilitates the sealing.

Further, in the third embodiment, the opening 35A communicating with the outside of the first scroll fluid machine 3A opens to the front end face portion 32A, but the opening 35B of the front end face portion 33B of the second scroll fluid machine 3B. 'Is closed. Similarly, the opening 35B communicating with the outside of the second scroll fluid machine 3B opens to the side surface portion 31B, but the opening 35A'of the first scroll fluid machine 3A is closed.

With the above configuration, in the Rankin evaporator 2, the second heat exchange medium that has been heat-exchanged with the first heat exchange medium supplied from a heat source such as engine waste heat and evaporated is a rotating shaft via the cap 49A. It flows into the through hole 47A penetrating the inside of 37A, and expands in the first and second expansion spaces 42A and 43A from the central portion of the first and second expansion spaces 42A and 43A toward the outermost peripheral end. It moves and rotates the rotating shaft 37A and the connecting shaft 30A. As a result, the second scroll fluid machine 3B can be operated via the connecting shaft 30B connected to the connecting shaft 30A of the first scroll fluid machine 3A.

As described above, according to the present invention, it is possible to operate the frozen sackle by utilizing the waste heat of the engine or the like.

1 Waste heat recovery system 2 Rankine evaporator 3 Composite fluid machine 3A 1st scroll fluid machine 3B 2nd scroll fluid machine 4 Rankine condenser 5 Pump 6 Rankine cycle 7 Refrigeration cycle condenser 8 Expansion means 9 Refrigeration cycle Evaporator for 10 Refrigeration cycle 11 Heating means

Claims (5)

A Rankin evaporator that exchanges heat with a first heat exchange medium moving from a heat source and evaporates a second heat exchange medium, and an expander that expands a second heat exchange medium evaporated by the Rankin evaporator. A Rankin cycle consisting of a Rankin condenser that condenses a second heat exchange medium expanded by an expander and a pump that supplies a second heat exchange medium condensed by the Rankin condenser to the Rankin evaporator. And a condenser for a refrigerating cycle that condenses a third heat exchange medium, an expansion means for adiabatic expansion of the third heat exchange medium condensed by the condenser for a refrigeration cycle, and a third heat expanded by the expansion means. In a waste heat recovery system consisting of a refrigerating cycle evaporator for evaporating an exchange medium and a refrigerating cycle composed of a compressor for compressing a third heat exchange medium evaporated by the refrigerating cycle evaporator.
The expander is a pressure-canceling first scroll fluid machine, and the compressor is a second scroll fluid machine having the same structure as the first scroll fluid machine, with the first scroll fluid machine. The second scroll fluid machine is back-to-back coupled via a connecting housing, and the connecting shaft of the first scrolling fluid machine is connected and fixed in the connecting housing to the connecting shaft of the second scroll fluid machine. A waste heat recovery system characterized by forming a composite fluid machine. The waste heat recovery system according to claim 1, wherein in the Rankine cycle of the waste heat recovery system, a heating means is provided between the rankine evaporator and the expander. A composite fluid machine used in the waste heat recovery system according to claim 1 or 2.
It consists of a substantially cylindrical side surface portion, a front end face portion located on one side of the side surface portion, and a rear end face portion located on the other side of the side surface portion, and defines an internal space and communicates the internal space with the outside. A housing provided with an opening, a rotating shaft rotatably supported by the front end face portion, a connecting shaft rotatably supported by the rear end face portion, and a radial spiral fixed to the rotating shaft. A first drive scroll member extending in a shape, a second drive scroll member fixed to the connecting shaft and extending radially in a radial direction, and a first drive scroll of the first drive scroll member. A spiral first driven scroll that meshes with and defines a first compressed space and a spiral that meshes with a second drive scroll of the second drive scroll member to define a second compressed space. The second driven scroll is provided with a driven scroll member rotatably held on the front end face portion and the rear end face portion, and the first and second compressed spaces are provided in the outer peripheral direction from the center. It is configured to gradually expand the space toward the direction, and the through hole provided through the rotation axis communicates with the innermost peripheral end of the first and second compressed spaces, and the first and second A pressure-canceling first scroll fluid machine in which the outermost end of the compressed space communicates with the internal space.
A second scroll fluid machine having the same configuration as the first scroll fluid machine is provided.
The second scroll hydraulic machine is arranged back-to-back with the first scroll fluid machine via a connecting housing, and the connecting shaft of the first scroll fluid machine and the second scroll fluid machine in the connecting housing. A composite fluid machine characterized in that it is connected and fixed to a connecting shaft. The first scroll fluid machine is used as a compressor constituting a part of the refrigeration cycle, and the second scroll fluid machine is used as an expander constituting a part of the Rankin cycle. Item 3. The composite fluid machine according to Item 3. The connecting housing defines a connecting space for accommodating a connecting portion between the connecting shaft of the first scroll fluid machine and the connecting shaft of the second scroll fluid machine, and the connecting space is the first scroll. The composite fluid machine according to claim 3 or 4, characterized in that it communicates with the internal space of the fluid machine.

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