WO2018028367A1

WO2018028367A1 - Multi-stage thermoacoustic generator unit and multi-stage heat regenerative refrigeration system having same

Info

Publication number: WO2018028367A1
Application number: PCT/CN2017/092223
Authority: WO
Inventors: 胡剑英; 罗二仓; 张丽敏; 吴张华
Original assignee: 中国科学院理化技术研究所
Priority date: 2016-08-10
Filing date: 2017-07-07
Publication date: 2018-02-15
Also published as: CN106194358B; CN106194358A

Abstract

A multi-stage thermoacoustic generator unit and a multi-stage heat regenerative refrigeration system having same. The multi-stage thermoacoustic generator unit comprises multiple sets of thermoacoustic engines which are sequentially connected between a compressor and a generator and are coupled with one another by means of resonator assemblies for enabling traveling-wave sound fields to be generated in each set of thermoacoustic engines simultaneously. By means of the resonator assemblies, the adjacent two sets of thermoacoustic engines match well with each other, and traveling-wave sound fields can be generated in each set of thermoacoustic engines simultaneously, such that the thermoelectricity efficiency of the thermoacoustic generator unit is improved. Moreover, by setting different operating temperatures for each set of thermoacoustic engines, the multi-stage thermoacoustic generator unit can use thermal energy of different grades in a stepped manner, such that the multi-stage heat regenerative refrigeration system having the unit has increased thermoelectric conversion efficiency.

Description

Multi-stage thermoacoustic generator set and multi-stage regenerative refrigeration system with the same

cross reference

This application is hereby incorporated by reference in its entirety in its entirety in its entirety the entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire This application.

Technical field

The invention relates to the technical field of thermoacoustic generator equipment, in particular to a multi-stage thermoacoustic generator set and a multi-stage regenerative refrigeration system having the same.

Background technique

A thermoacoustic engine is a new type of power unit that converts thermal energy into mechanical energy. If it is connected to a generator, the mechanical energy is converted into electrical energy to form a thermoacoustic generator. The thermoacoustic generator is an external combustion type power generation equipment that can generate electricity by using waste heat, solar energy, industrial waste heat, etc., and thus has broad application prospects.

At present, the existing thermoacoustic engine is shown in FIG. 1, and its core components include a main water cooler 1, a regenerator 2, a heater 3, a heat buffer tube 4, and a sub-water cooler 5. When the mechanical energy in the form of sound waves is input from the main water cooler 1, if the heater 3 is heated at this time, a certain temperature gradient is formed in the axial direction of the regenerator 2, the energy of the sound wave is amplified in the regenerator 2, Thereby, more mechanical energy is output outward at the secondary water cooler 5. The mechanical energy in the form of sound waves can drive the piston 6 of the generator to move, cutting the magnetic lines of force, thereby converting mechanical energy into electrical energy. The secondary water cooler 5 mainly operates the generator piston 6 at a lower temperature, and the heat buffer tube 4 is used to connect the high temperature heater 3 and the lower temperature secondary water cooler 5 to provide heat buffering and heat reduction. The role of loss. The sound waves input to the engine can be generated by the reciprocating motion of the compressor piston 7.

According to the experiment, if the temperature of the heater 3 of the thermoacoustic engine is 873K and the temperature of the two room temperature water coolers is 300K, the energy of the sound wave can be enlarged to about 2.5 times after passing through the thermoacoustic engine, and the thermoacoustic engine converts the heat energy. The efficiency of sound energy is about 40%, and the efficiency of general compressors and generators is about 85%. Assuming that the output sound of the compressor is 1 kW, the compressor consumes about 1.176 kW of electric power, and the output sound of the engine is about 2.5 kW. The energy output is about 3.75kW, and the output power of the generator is about 2.125kW. The net output power is about 0.959kW, and the thermoelectric efficiency of the whole machine is 25.3%. It can be seen that although the heat-to-work efficiency of the thermoacoustic engine can reach 40%, the thermoelectric efficiency of the system has become very low because of the conversion between electricity and work.

In order to eliminate the loss of the electro-acoustic conversion process of the compressor and improve the efficiency, another structure of the thermoacoustic generator has been proposed. As shown in FIG. 2, a part of the sound power flowing out from the thermoacoustic engine is fed back to the main water cooler of the thermoacoustic engine by using a feedback tube 11, thereby realizing the cyclic amplification of the sound power. The power generation efficiency of the whole machine in this structure is basically equal to the thermoacoustic conversion efficiency of the engine and the acoustic-electric conversion efficiency of the generator, that is, about 34%. In this structure, although there is no electro-acoustic conversion process of the compressor, the efficiency can be improved, but the phase angle of the pressure wave and the volume flow at the generator piston is close to 90° (the corresponding phase angle in the structure of Fig. 1 is about 60°) This makes the scavenging volume of the generator piston increase several times under the same power generation, which brings great difficulty to the design of the motor and is therefore not widely used.

At present, there are also acoustic double-acting engines and mechanical double-acting structures. The former has large loss of resonance tube and low efficiency, and the latter system has problems of system operation instability, so it is not widely used.

The current thermoacoustic generators and Stirling generator systems are mainly used to adjust the amplitude of the system by changing the heating temperature. Due to the presence of heat capacity, the amplitude of the system cannot respond immediately to load changes, which is very likely to cause the motor. Destroyed by hitting the cylinder. The operating frequency of the system is determined by its own structure and cannot be adjusted. The output of the motor must pass through the inverter to input into the grid, which is not only complicated but also reduces efficiency.

In summary, the existing thermoacoustic generators have the disadvantages of low efficiency and difficulty in matching the design of the motor; the temperature of the heaters of the current thermoacoustic generators is usually fixed, and it is difficult to use the thermal energy of different temperature grades in cascade; The amplitude cannot be changed instantaneously, so the control is complicated; in addition, the frequency cannot be actively adjusted, so an additional inverter system must be added to access the Internet.

Summary of the invention

(1) Technical problems to be solved

The technical problem to be solved by the present invention is to provide a multi-stage thermoacoustic generator set and a multi-stage regenerative refrigeration system having the same, which can improve the thermoelectric efficiency of the thermoacoustic generator set and realize the cascade utilization of different grades of thermal energy. And at the same time realize the instantaneous change of the system amplitude and the main frequency Dynamic adjustment.

(2) Technical plan

In order to solve the above technical problem, the present invention provides a multi-stage thermoacoustic generator set comprising a plurality of sets of thermoacoustic engines, the plurality of sets of the thermoacoustic engines being sequentially connected in series between a compressor and a generator, and each group is described The thermoacoustic engines are each coupled by a harmonic sub-assembly for enabling simultaneous formation of a traveling wave sound field in each of the sets of thermoacoustic engines.

Further, the resonant subassembly includes a mass piston and a resonant spring, each set of the thermoacoustic engine has an acoustic wave inlet at one end and a mechanical energy outlet at the other end, the resonant spring has one end fixed and the other end The mass piston is disposed between the mechanical energy outlets and the acoustic inlets of two adjacent sets of the thermoacoustic engines.

Further, the mass piston and the resonant spring are mounted in series between the mechanical energy outlets and the acoustic wave inlets of two adjacent sets of the thermoacoustic engines.

Further, a bypass groove is disposed between the mechanical energy outlet and the acoustic wave inlet of the adjacent two groups of the thermoacoustic engines, and the mass piston is installed in the bypass groove.

Further, the resonant subassembly includes a resonance tube having an inner diameter smaller than an inner diameter of the thermoacoustic engine.

Further, the thermoacoustic engine includes a main water cooler, a regenerator, and a heater that are sequentially connected, and the main water cooler is connected to a compressor that is connected to the generator.

Further, the thermoacoustic engine further includes a heat buffer tube and a secondary water cooler, and the heat buffer tube and the sub water cooler are sequentially connected between the heater and the generator, or between the heater and the resonator.

Further, the compressor is provided with a compressor piston, and the main water cooler is connected to the compressor piston.

Further, the generator is provided with a generator piston, and the secondary water cooler is connected to the generator piston.

The present invention also provides a multi-stage regenerative refrigeration system characterized by comprising a multi-stage thermoacoustic generator set as described above.

(3) Beneficial effects

The above technical solution of the present invention has the following beneficial effects: the multi-stage thermoacoustic generator set of the present invention comprises a plurality of sets of thermoacoustic engines, and the plurality of sets of thermoacoustic engines are sequentially connected in series to the compressor and the generator. And each group of thermoacoustic engines are coupled by a resonant sub-assembly. The resonant sub-assembly is used to simultaneously form a traveling wave sound field in each group of thermoacoustic engines, and the two sets of thermoacoustic engine groups are made by the resonant sub-assembly. A good match is obtained, and a traveling wave sound field can be simultaneously formed in each group of thermoacoustic engine groups, thereby improving the thermoelectric efficiency of the thermoacoustic generator set, and at the same time, setting the operating temperature of each group of thermoacoustic engines to different temperatures, thereby The multi-stage thermoacoustic generator set can also realize the step utilization of different grades of thermal energy, so that the multi-stage regenerative refrigeration system with the unit has higher thermoelectric conversion efficiency and maximizes system working efficiency.

Since the frequency and amplitude of the input sound waves are actively controlled by the compressor, the amplitude and frequency of the system can be controlled instantaneously by the compressor. When the load out point change is such that the motor amplitude is too large, the input work of the compressor can be immediately reduced. Conversely, when the motor amplitude is insufficient, the input work of the compressor can be increased. The frequency of compression can be set to exactly match the grid frequency, and can be actively adjusted in a small range, so the power output from the generator can be directly matched to the grid without the need for an inverter process.

DRAWINGS

1 is a schematic structural view of a prior art thermoacoustic generator;

2 is a schematic structural view of another thermoacoustic generator of the prior art;

3 is a schematic structural view of a thermoacoustic generator set according to Embodiment 1 of the present invention;

4 is a schematic structural view of a thermoacoustic generator set according to Embodiment 2 of the present invention;

Figure 5 is a schematic structural view of a thermoacoustic generator set according to a third embodiment of the present invention;

6 is a schematic structural view of a thermoacoustic generator set according to Embodiment 4 of the present invention;

Among them, 1, the main water cooler; 2, regenerator; 3, heater; 4, heat buffer tube; 5, secondary water cooler; 6, generator piston; 7, compressor piston; 8, mass piston; Resonant spring; 10, resonance tube; 11, feedback tube.

detailed description

Embodiments of the present invention will be further described in detail below with reference to the drawings and embodiments. The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.

In the description of the present invention, "multiple" or "multiple sets" means two (two groups) or two (two groups) or more unless otherwise stated. The terms "upper", "lower", "left", "right", "inside", "outside", "front end", "back end", "head", "tail", etc. The position or positional relationship is based on the orientation or positional relationship shown in the drawings, and is merely for the convenience of the description of the present invention and the simplified description, and does not indicate or imply that the device or component referred to has a specific orientation, is constructed in a specific orientation, and The operation is therefore not to be construed as limiting the invention.

In the description of the present invention, it should be noted that the terms "installation", "connected", and "connected" are to be understood broadly, and may be fixed or detachable, for example, unless otherwise explicitly defined and defined. Connected, or integrally connected; can be mechanical or electrical; can be directly connected or indirectly connected through an intermediate medium. The specific meaning of the above terms in the present invention can be understood in a specific case by those skilled in the art.

Embodiment 1

As shown in FIG. 3, the multi-stage thermoacoustic generator set provided in this embodiment includes a plurality of sets of thermoacoustic engines, and a plurality of sets of thermoacoustic engines are sequentially connected in series between the compressor and the generator, and each group of thermoacoustic engines is between Through the coupling of the resonator sub-assembly, the resonator sub-assembly is used to enable the formation of a traveling wave sound field in each group of thermoacoustic engines, and the resonator sub-assembly is used to obtain a good match between the two groups of thermoacoustic engine groups in each group of heat. The traveling wave sound field can be simultaneously formed in the acoustic engine group, thereby improving the thermoelectric efficiency of the thermoacoustic generator set, and at the same time, setting the operating temperature of each group of thermoacoustic engines to different temperatures, thereby also enabling the multi-stage thermoacoustic generator set to be realized. Cascade utilization of different grades of thermal energy.

The thermoacoustic engine includes a main water cooler 1, a regenerator 2, a heater 3, a heat buffer tube 4 and a sub water cooler 5 which are connected in series, the main water cooler 1 is connected to the compressor, and the sub water cooler 5 is connected to the generator. Further, the heat buffer tube 4 and the sub-water cooler 5 may be sequentially connected between the heater 3 and the resonator sub-assembly. In order to ensure reliable generation of sound waves input into the thermoacoustic engine, it is preferable that the main water cooler 1 is connected to the compressor through the compressor piston 7, and the reciprocating motion of the compressor piston 7 can generate reliable sound waves, and thus the thermoacoustic engine and the compressor piston The end of the 7 connection is the sound wave inlet. In order to ensure that the mechanical energy generated by the thermoacoustic engine can be reliably converted into electrical energy, it is preferred that the secondary water cooler 5 is connected to the generator through the generator piston 6, and the thermoacoustic engine uses mechanical energy to push the movement of the generator piston 6 to cut the magnetic lines of force, thereby mechanical energy. It is converted into electrical energy, so the end of the thermoacoustic engine connected to the generator piston 6 is a mechanical energy outlet.

In the multi-stage thermoacoustic generator set of the first embodiment, two sets of thermoacoustic engines are sequentially installed between the compressor and the generator, and the two sets of thermoacoustic engines are coupled by a resonance sub-assembly. Specifically, this embodiment A resonant sub-assembly includes a mass piston 8 and a resonant spring 9. Since each group of thermoacoustic engines has an acoustic wave inlet at one end and a mechanical energy outlet at the other end, two adjacent sets of thermal sounds are emitted. In the motive, the mechanical energy outlets of the former group of thermoacoustic engines are in communication with the acoustic wave inlets of the latter group of thermoacoustic engines to ensure that the direction of energy conversion between the plurality of thermoacoustic engines is uniform; the mass piston 8 and the resonant spring 9 are mounted to the phase Between the mechanical energy outlets of the two sets of thermoacoustic engines and the acoustic wave inlet, the resonant spring 9 is connected to the mass piston 8, and the mass piston 8 can reciprocate toward the acoustic wave inlet direction of the thermoacoustic engine. .

For thermoacoustic engines, to achieve higher thermoacoustic conversion efficiency, the internal sound field conditions are essential, and the traveling wave sound field must be realized in the middle of the regenerator 2, while the traveling wave sound field is adjusted by the compressor piston 7 and The mass of the generator piston 6 and the internal spring stiffness thereof are realized, and each group of thermoacoustic engines are coupled by a resonator sub-assembly, and the resonator sub-assembly can adjust the dynamic mass and spring stiffness of the mass piston 8 to make adjacent A good match between the two thermoacoustic engines is achieved, so that a traveling wave sound field is simultaneously generated in the regenerator 2 of the two thermoacoustic engines. The resonator sub-assembly has the function of transmitting sound waves to match the sound field without energy conversion, so the energy passing through the resonator sub-assembly has a high pass efficiency, usually up to about 95%.

Assuming that the parameters of the efficiency of the generator, the compressor, the thermoacoustic engine and the like are the same as those described in the background art, in the multi-stage thermoacoustic generator set of the first embodiment, the thermoacoustic engine close to the compressor is the first-order thermoacoustic engine. The thermoacoustic engine close to the generator is a two-stage thermoacoustic engine. When 1kW of sound power is input into the first-stage thermoacoustic engine, the electric power consumption is still 1.176kW, and the sound output of the first-stage thermoacoustic engine is 2.5kW. The resonant sound component of the resonant sub-assembly becomes 2.375 kW, the acoustic power output of the secondary thermoacoustic engine is 5.938 kW, the output power of the generator is 5.047 kW, and the total thermoelectric conversion efficiency of the thermoacoustic generator is 30.58%. It can be seen that after the addition of the first-class thermoacoustic engine, the total efficiency of the system is greatly improved.

In addition, in order to ensure that the cascade utilization of different grades of thermal energy can be realized, in the multi-stage thermoacoustic generator set, the heaters 3 of the respective thermoacoustic engines can adopt different heating temperatures, for example, if there is 900K of flue gas, it can be utilized. One of the thermoacoustic engines is a first-grade thermoacoustic engine, so that the heater 3 of the first-stage thermoacoustic engine absorbs the heat of the flue gas, and the temperature thereof is lowered to about 800K (the operating temperature of the first-stage thermoacoustic engine is 800K), and the smoke is utilized. The heat released by the gas from 900K to 800K drives the first-order thermoacoustic engine to work. Then use another thermoacoustic engine as the secondary thermoacoustic engine, and use the heater 3 of the secondary thermoacoustic engine to absorb the heat of the flue gas, and reduce the temperature to about 700K (the operating temperature of the secondary thermoacoustic engine is 700K). ), using the heat released by the flue gas from 800K to 700K, Q2 drives the secondary thermoacoustic engine. If the ambient temperature is 300K, the maximum sound power W that can be converted by the two thermoacoustic engines is:

W=Q1×(1-300/800)+Q2×(1-300/700)

If there is only one thermoacoustic engine, although the heater 3 can also absorb the heat released by the flue gas from 900K to 700K, since the heater 3 can only work at a single temperature, the operating temperature of the separate thermoacoustic engine is only Can be 700K, so the maximum sound work W' that the thermoacoustic engine can convert is:

W’=(Q1+Q2)×(1-300/700)

Obviously, W' is less than W. Therefore, when only a separate thermoacoustic engine is used, the step utilization of heat cannot be performed, and at this time, less sound power can be converted.

Embodiment 2

The multi-stage thermoacoustic engine set of the second embodiment is basically the same as the multi-stage thermoacoustic engine set described in the first embodiment, and the same points are not described again. The difference is that the multi-stage thermoacoustic generator set of the second embodiment There are three sets of thermoacoustic engines sequentially installed between the compressor and the generator, and each set of thermoacoustic engines is coupled by a resonant sub-assembly, the resonant sub-assembly is assembled, the resonant spring 9 and the mass piston 8 In connection, the mass piston 8 can reciprocate toward the acoustic wave inlet of the thermoacoustic engine.

On the basis of the first embodiment, the multi-stage thermoacoustic generator set of the second embodiment increases the number of thermoacoustic engines to three, as shown in FIG. 4, therefore, the thermoelectricity of the multi-stage thermoacoustic generator set under the same conditions. Efficiency will increase to 32%. Similarly, if the number of thermoacoustic engines is increased to four, the thermoelectric efficiency of the multi-stage thermoacoustic generator set under the same conditions can be increased to 32.7%. Theoretically, if the efficiency of the resonator is 1, then as the number of engines increases, the efficiency of the system will approach the product of the thermoacoustic engine efficiency and the efficiency of the generator, and the influence of the compressor will gradually disappear.

In addition, according to the calculation data in the first embodiment, it can be concluded that if more thermoacoustic engines are installed in the multi-stage thermoacoustic generator set, more heat can be absorbed from the flue gas for driving, and each thermoacoustic engine is driven. The operating temperatures are set at different temperatures to achieve a cascade of flue gas heat.

Embodiment 3

As shown in FIG. 5, the multi-stage thermoacoustic engine group of the third embodiment is basically the same as the multi-stage thermoacoustic engine group of the first embodiment, and the same points are not described again, except that: the third embodiment When the resonator subassembly is installed, a bypass groove is provided between the mechanical energy outlet and the acoustic wave inlet of the adjacent two sets of thermoacoustic engines, and the mass piston 8 is installed in the bypass groove by the resonant spring 9.

Embodiment 4

As shown in FIG. 6 , the multi-stage thermoacoustic engine group of the fourth embodiment is basically the same as the multi-stage thermoacoustic engine group described in the first embodiment, and the same points are not described again, except that: The resonator sub-assembly comprises a resonance tube 10 having an inner diameter smaller than the inner diameter of the thermoacoustic engine, having a gas in the resonance tube 10, the gas having a predetermined inertia and elasticity, and utilizing the inertia of the gas in the resonance tube 10 and the gas elasticity to generate resonance The function is to enable the two groups of thermoacoustic engines connected to both ends of the resonance tube 10 to simultaneously form a traveling wave sound field, thereby obtaining a good match between the two groups of thermoacoustic engine groups, thereby improving the thermoelectricity of the thermoacoustic generator set. effectiveness.

Embodiment 5

The fifth embodiment provides a multi-stage regenerative refrigeration system, which includes at least one of the four embodiments as described above, and may also adopt the above four embodiments. Several multi-stage thermoacoustic generator sets are installed in a mixed manner. The multi-stage regenerative refrigeration system has higher thermoelectric conversion efficiency and can maximize system efficiency.

In summary, in various embodiments of the present invention, the multi-stage thermoacoustic generator set includes a plurality of sets of thermoacoustic engines, and the plurality of sets of thermoacoustic engines are sequentially connected in series between the compressor and the generator, and each group of thermoacoustic engines Each of them is coupled by a resonator sub-assembly, which is used to enable a traveling wave sound field to be simultaneously formed in each group of thermoacoustic engines, and a harmonic sub-competition is used to obtain a good match between adjacent two groups of thermoacoustic engine groups. The traveling acoustic wave field can be simultaneously formed in the group of thermoacoustic engine groups, thereby improving the thermoelectric efficiency of the thermoacoustic generator set, and simultaneously setting the operating temperature of each group of thermoacoustic engines to different temperatures, thereby further enabling the multi-stage thermoacoustic power generation. The unit realizes the cascade utilization of different grades of thermal energy, so that the multi-stage regenerative refrigeration system with the unit has higher thermoelectric conversion efficiency and maximizes system working efficiency.

Further, since the frequency and amplitude of the input sound wave are actively controlled by the compressor, the amplitude and frequency of the system can be controlled instantaneously by the compressor. When the load out point change is such that the motor amplitude is too large, the input work of the compressor can be immediately reduced. Conversely, when the motor amplitude is insufficient, the input work of the compressor can be increased. The frequency of compression can be set to exactly match the grid frequency, and can be actively adjusted in a small range, so the power output from the generator can be directly matched to the grid without the need for an inverter process.

The embodiments of the present invention have been presented for purposes of illustration and description, and are not intended to Many modifications and variations will be apparent to those skilled in the art. The embodiment was chosen and described in order to best explain the principles and embodiments of the invention,

Claims

A multi-stage thermoacoustic generator set includes a plurality of sets of thermoacoustic engines, a plurality of sets of said thermoacoustic engines are sequentially connected in series between a compressor and a generator, and each group of said thermoacoustic engines is between Coupled by a resonant subassembly, the resonant subassembly is configured to simultaneously form a traveling wave sound field in each of the sets of thermoacoustic engines.
A multi-stage thermoacoustic generator set according to claim 1, wherein said resonant sub-assembly comprises a mass piston and a resonant spring, each set of said thermoacoustic engine having an acoustic wave inlet at one end and the other end being provided The mechanical energy outlet has one end fixed to the other end and the other end connected to the mass piston, and the mass piston is disposed between the mechanical energy outlets and the acoustic wave inlets of the adjacent two sets of the thermoacoustic engines.
The multi-stage thermoacoustic generator set according to claim 2, wherein said mass piston and said resonant spring are mounted in series between adjacent mechanical energy outlets and acoustic inlets of said two sets of said thermoacoustic engines.
The multi-stage thermoacoustic generator set according to claim 2, wherein a bypass groove is provided between the mechanical energy outlet and the acoustic wave inlet of the adjacent two groups of said thermoacoustic engines, and said mass piston is installed in the bypass Inside the groove.
The multi-stage thermoacoustic generator set according to claim 1, wherein said resonant sub-assembly comprises a resonance tube having an inner diameter smaller than an inner diameter of said thermoacoustic engine.
A multi-stage thermoacoustic generator set according to any one of claims 1 to 5, wherein the thermoacoustic engine comprises a main water cooler, a regenerator and a heater connected in series, the main water cooler Connected to a compressor that is coupled to a generator.
The multi-stage thermoacoustic generator set according to claim 6, wherein said thermoacoustic engine further comprises a heat buffer tube and a sub-water cooler, said heat buffer tube and said sub-water cooler being sequentially connected to said heater Between the generator and the heater and the resonant subassembly.
A multi-stage thermoacoustic generator set according to claim 6 or claim 7 wherein said compressor is provided with a compressor piston, said main water cooler being coupled to the compressor piston.
The multi-stage thermoacoustic generator set according to claim 7, wherein said generator is provided with a generator piston, and said sub-water cooler is coupled to the generator piston.
A multi-stage regenerative refrigeration system characterized by comprising a multi-stage thermoacoustic generator set according to any of claims 1-9.