Low-temperature refrigerating system utilizing heat energy and control method

Abstract

The invention relates to the technical field of low-temperature refrigeration, and provides a low-temperature refrigeration system utilizing heat energy and a control method.The system comprises a thermo-acoustic engine, a thermo-acoustic refrigerator and an acoustic-power shunting part, the inlet end of the thermo-acoustic refrigerator is connected to the outlet end of the thermo-acoustic engine, and the outlet end of the thermo-acoustic refrigerator is connected to the inlet end of the thermo-acoustic engine; the acoustic power shunting component comprises an acoustic power shunting channel and a control piece, the acoustic power shunting channel is connected between the inlet end of the thermoacoustic refrigerator and the outlet end of the thermoacoustic refrigerator, and the control piece is arranged on the acoustic power shunting channel and used for controlling disconnection, connection and the opening degree of the acoustic power shunting channel. The outlet end of the thermo-acoustic refrigerator is connected to the inlet end of the thermo-acoustic engine, so that a loop design is formed, recovery of expansion work is achieved, and the heat energy utilization rate is increased; and acoustic power is shunted at an inlet of the thermo-acoustic refrigerator through the acoustic power shunting channel, so that the system can realize higher refrigerating efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of low-temperature refrigeration, and in particular to a low-temperature refrigeration system utilizing thermal energy and a control method thereof. Background Art

[0002] Traditional methods of using high-temperature heat energy to obtain refrigeration effects mainly include absorption refrigeration and adsorption refrigeration. Although these methods can achieve the conversion of heat energy into cold energy to a certain extent, they cannot reach extremely low temperature areas (such as the temperature range required for liquefied natural gas or lower temperature areas), or it is difficult to obtain a large cooling capacity at low temperatures.

[0003] In recent years, thermoacoustic heat engines have attracted widespread attention as a new type of heat-to-work conversion device. Thermoacoustic heat engines can be divided into two categories: one is a thermoacoustic engine that converts external heat into acoustic work; the other is a thermoacoustic refrigerator that uses acoustic work to produce refrigeration / cryogenic effects. In theory, by coupling a thermoacoustic engine with a thermoacoustic refrigerator, an efficient conversion system from high-temperature thermal energy to low-temperature refrigeration effect can be constructed. This combination not only inherits the inherent advantages of thermoacoustic technology, such as high efficiency, no moving parts, and environmental friendliness, but also provides a new idea for solving the problems of traditional refrigeration technology in low-temperature applications.

[0004] In the prior art, such as Figure 1 As shown in the figure, a method of using thermal energy to generate low temperature based on thermoacoustic technology is to use a thermoacoustic engine to drive a pulse tube refrigerator that does not recover expansion work to achieve low temperature, which can achieve refrigeration effects in the temperature range of liquefied natural gas (120K), liquid nitrogen (77K) and even liquid hydrogen (20K); however, the expansion work of the pulse tube refrigerator driven by the thermoacoustic engine cannot be effectively recovered, but is dissipated in the phase adjustment mechanism in the form of heat, which not only reduces the thermal energy utilization rate of the entire system, but may also cause the performance of the phase adjustment mechanism to be affected by the temperature rise, and then additional cooling measures are required to maintain normal operation, which increases the complexity and cost of the system; especially after the cooling capacity increases to a certain extent, it seriously affects the stability and economy of the system.

[0005] In order to realize the recovery of the expansion work of the refrigerator, Figure 2 As shown, a thermoacoustic engine is used to drive a thermoacoustic refrigerator with recoverable expansion work to achieve low temperature and reach the liquefied natural gas temperature zone, but its refrigerator is directly connected to the engine and has inherent temperature limitations, which restricts the improvement of system performance. Summary of the invention

[0006] The present invention provides a low-temperature refrigeration system and a control method using thermal energy, which are used to solve the defect in the prior art that the inherent temperature limitation restricts the improvement of system performance.

[0007] The present invention provides a low-temperature refrigeration system utilizing thermal energy, comprising a thermoacoustic coupling unit, wherein the thermoacoustic coupling unit comprises: Thermoacoustic engines; A thermoacoustic refrigerator, wherein the inlet end of the thermoacoustic refrigerator is connected to the outlet end of the thermoacoustic engine, and the outlet end of the thermoacoustic refrigerator is connected to the inlet end of the thermoacoustic engine; The acoustic power shunt component comprises an acoustic power shunt channel and a control component, wherein the acoustic power shunt channel is connected between the inlet end of the thermoacoustic refrigerator and the outlet end of the thermoacoustic refrigerator, and the control component is arranged in the acoustic power shunt channel, and the control component is used to control the disconnection, conduction and opening of the acoustic power shunt channel.

[0008] According to a low-temperature refrigeration system utilizing thermal energy provided by the present invention, a phase adjustment device is provided at the outlet end of the thermoacoustic refrigerator.

[0009] According to a low-temperature refrigeration system utilizing thermal energy provided by the present invention, the thermoacoustic engine and / or the thermoacoustic refrigerator is provided with a pressure wave generator.

[0010] According to a low-temperature refrigeration system utilizing thermal energy provided by the present invention, the thermoacoustic engine comprises an engine room temperature end heat exchanger, an engine regenerator, an engine hot end heat exchanger and an engine thermal buffer tube connected in sequence, and the engine thermal buffer tube is connected to the inlet end of the thermoacoustic refrigerator; The pressure wave generator is arranged in the engine heat buffer tube or is connected to the engine heat buffer tube in a bypass manner, or is arranged on a side of the engine room temperature end heat exchanger away from the engine regenerator.

[0011] According to a low-temperature refrigeration system utilizing thermal energy provided by the present invention, an active-electric conversion device is provided at the outlet end of the thermoacoustic refrigerator. When the system does not require pressure wave assistance, the active-electric conversion device is used for mechanical phase modulation; when the system requires pressure wave assistance, the active-electric conversion device is used to generate auxiliary pressure waves.

[0012] According to a low-temperature refrigeration system utilizing thermal energy provided by the present invention, there are a plurality of thermoacoustic coupling units, and the plurality of thermoacoustic coupling units are connected end to end.

[0013] According to a low-temperature refrigeration system utilizing thermal energy provided by the present invention, the phase modulation device is one of an acoustic phase modulation device, a liquid phase modulation device, and a solid phase modulation device.

[0014] A low-temperature refrigeration system utilizing thermal energy provided by the present invention further comprises a temperature measuring element and a controller, wherein the thermoacoustic refrigerator comprises a refrigerator cold end heat exchanger; The temperature measuring element is arranged on the cold end heat exchanger of the refrigerator, and the controller is connected to the temperature measuring element and the control element respectively.

[0015] The present invention also provides a control method for the low-temperature refrigeration system using thermal energy as described above, comprising: When the acoustic power generated by the thermoacoustic engine does not match the acoustic power consumed by the thermoacoustic refrigerator, the control component controls the acoustic power shunt channel to be open, so that part of the acoustic power generated by the thermoacoustic engine enters the outlet end of the thermoacoustic refrigerator through the acoustic power shunt channel.

[0016] According to a control method of a low-temperature refrigeration system using thermal energy provided by the present invention, when the acoustic power generated by the thermoacoustic engine does not match the acoustic power consumed by the thermoacoustic refrigerator, controlling the acoustic power shunt channel to be open by a control element comprises: Obtain the current temperature or current cooling capacity of the cold end heat exchanger of the thermoacoustic refrigerator; When the current temperature is lower than the preset temperature or the current cooling capacity is higher than the preset cooling capacity, the conductance of the acoustic power diversion channel is controlled to decrease by the control element; When the current temperature is greater than the preset temperature or the current cooling capacity is less than the preset cooling capacity, the conductance of the acoustic power diversion channel is increased by controlling the control component.

[0017] The low-temperature refrigeration system utilizing heat energy provided by the present invention connects the outlet end of the thermoacoustic refrigerator to the inlet end of the thermoacoustic engine to form a loop design, realizes the recovery of expansion work, and thus improves the utilization rate of heat energy; and is connected between the inlet end and the outlet end of the thermoacoustic refrigerator through an acoustic power shunt channel, and the acoustic power shunt channel shunts the acoustic power at the inlet of the thermoacoustic refrigerator to break the temperature matching limitation between the thermoacoustic engine and the thermoacoustic refrigerator, so that the system can efficiently work in the specified refrigeration temperature zone when the heating temperature is high or low, thereby being able to achieve higher refrigeration efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 It is a schematic diagram of the structure of a pulse tube refrigerator driven by an existing thermoacoustic engine.

[0020] Figure 2 It is a structural schematic diagram of a thermoacoustic refrigerator driven by an existing thermoacoustic engine.

[0021] Figure 3 This is one of the structural schematic diagrams of the low-temperature refrigeration system utilizing thermal energy provided by the present invention.

[0022] Figure 4 This is the second structural schematic diagram of the low-temperature refrigeration system utilizing thermal energy provided by the present invention.

[0023] Figure 5 This is the third structural schematic diagram of the low-temperature refrigeration system utilizing thermal energy provided by the present invention.

[0024] Figure 6 This is the fourth structural schematic diagram of the low-temperature refrigeration system utilizing thermal energy provided by the present invention.

[0025] Figure 7 This is the fifth structural schematic diagram of the low-temperature refrigeration system utilizing thermal energy provided by the present invention.

[0026] Figure 8 This is the sixth structural schematic diagram of the low-temperature refrigeration system utilizing thermal energy provided by the present invention.

[0027] Fig. 9 This is the seventh structural schematic diagram of the low-temperature refrigeration system utilizing thermal energy provided by the present invention.

[0028] Fig.10 This is the eighth structural schematic diagram of the low-temperature refrigeration system utilizing thermal energy provided by the present invention. 100. Thermoacoustic coupling unit; 110. Thermoacoustic engine; 120. Thermoacoustic refrigerator; 130. Acoustic power diversion component; 1. Engine room temperature end heat exchanger; 2. Engine regenerator; 3. Engine hot end heat exchanger; 4. Engine thermal buffer tube; 5. Refrigerator room temperature end heat exchanger; 6. Refrigerator regenerator; 7. Refrigerator cold end heat exchanger; 8. Refrigerator thermal buffer tube; 9. Acoustic power diversion channel; 10. Control element; 11. Phase adjustment device; 12. Pressure wave generator; 13. Power-electricity conversion device; 14. Compression piston; 15. Expansion piston; 16. Displacer; 17. Power piston. DETAILED DESCRIPTION

[0029] The following embodiments of the present invention are described in further detail in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0030] In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limitations on the embodiments of the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0031] In the description of the embodiments of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0032] In the embodiments of the present invention, unless otherwise clearly specified and limited, the first feature being "above" or "below" the second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0033] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0034] Combine the following Figure 3-Figure 8 A low temperature refrigeration system utilizing thermal energy according to the present invention is described.

[0035] The embodiment of the first aspect of the present invention provides a low temperature refrigeration system utilizing thermal energy, such as Figure 3 As shown, the low-temperature refrigeration system includes a thermoacoustic coupling unit 100 , which includes a connected thermoacoustic engine 110 and a thermoacoustic refrigerator 120 , and an acoustic power splitting component 130 connected between the thermoacoustic engine 110 and the thermoacoustic refrigerator 120 .

[0036] Specifically, the inlet end of the thermoacoustic refrigerator 120 is connected to the outlet end of the thermoacoustic engine 110, and the outlet end of the thermoacoustic refrigerator 120 is connected to the inlet end of the thermoacoustic engine 110; the acoustic power shunt component 130 includes an acoustic power shunt channel 9 and a control component 10, the acoustic power shunt channel 9 is connected between the inlet end of the thermoacoustic refrigerator 120 and the outlet end of the thermoacoustic refrigerator 120, and the control component 10 is arranged in the acoustic power shunt channel 9, and the control component 10 is used to control the disconnection, conduction and opening of the acoustic power shunt channel 9.

[0037] It can be understood that the thermoacoustic engine 110 generates acoustic power, part of which is transmitted and enters the thermoacoustic refrigerator 120. Due to the acoustic cooling effect, part of the acoustic power is consumed in the thermoacoustic refrigerator 120 to obtain cooling capacity, and the other part of the acoustic power enters the inlet of the thermoacoustic engine 110. The recovered acoustic power will be amplified after entering the thermoacoustic engine 110, and this reciprocating cycle will enable the system to achieve continuous and stable operation.

[0038] like Figure 2 As shown, according to theoretical derivation, the hot end heating temperature , cold end temperature And medium temperature exothermic environment temperature There is a certain constraint relationship between ≈ When the hot end is heated to When the temperature is too high, the acoustic power generated by the thermoacoustic engine is too much to be effectively used by the thermoacoustic refrigerator, resulting in a mismatch between the acoustic power of the two. It can be seen that the purpose of increasing the relative Carnot efficiency of the system is to increase the heating temperature, resulting in a mismatch in the system temperature, and it is impossible to obtain better performance, that is, it is impossible to obtain higher cooling efficiency. Similarly, in the case of low-temperature refrigeration such as 120K and below, the cold end temperature Lower, to achieve higher system efficiency, a higher heating temperature is required Otherwise, the acoustic power generated by the thermoacoustic engine will be insufficient, reducing the efficiency and reliability of the system. It should be noted here that in actual operation, in order to ensure the stability and efficiency of the system, the hot end heating temperature Usually it is maintained in a relatively stable range. If the hot end heating temperature is increased to increase the acoustic power generated by the thermoacoustic engine, , which involves higher requirements on the internal components of the thermoacoustic engine, etc., which will obviously increase the cost and technical complexity. Considering the above factors and the limited temperature of the heating heat source, the hot end heating temperature of the thermoacoustic engine will not be increased in practical applications. Based on this, the present invention connects the acoustic power shunt channel 9 between the inlet end of the thermoacoustic refrigerator 120 and the outlet end of the thermoacoustic refrigerator 120 to realize the shunt of the acoustic power at the inlet of the thermoacoustic refrigerator 120, breaking the temperature matching limit between the thermoacoustic engine 110 and the thermoacoustic refrigerator 120.

[0039] It can be understood that at the inlet of the thermoacoustic refrigerator 120, the control unit 10 controls the acoustic power shunt channel 9 to be turned on, so as to shunt the acoustic power at the outlet of the thermoacoustic engine 110, so that it is not consumed by the thermoacoustic refrigerator 120 but directly enters the inlet of the thermoacoustic engine 110 for recovery. In this way, by setting the acoustic power shunt channel 9 and the control unit 10, the mismatch problem between the acoustic power generated by the thermoacoustic engine 110 and the acoustic power consumed by the thermoacoustic refrigerator 120 is avoided, breaking the temperature matching limitation of the traditional direct-connected heat-driven refrigeration system, and achieving effective matching of the acoustic field impedance, phase and power flow, thereby achieving a larger cooling capacity and higher cooling efficiency to improve system performance.

[0040] The low-temperature refrigeration system using thermal energy provided by the embodiment of the present invention is configured such that the inlet end of the thermoacoustic refrigerator 120 is connected to the outlet end of the thermoacoustic engine 110, and the outlet end of the thermoacoustic refrigerator 120 is connected to the inlet end of the thermoacoustic engine 110, so as to form a loop design, realize the recovery of expansion work, and thus improve the utilization rate of thermal energy; and the acoustic work is diverted at the inlet of the thermoacoustic refrigerator 120 through the acoustic work diversion channel 9, so as to break the temperature matching limitation between the thermoacoustic engine 110 and the thermoacoustic refrigerator 120, so that the system can work efficiently in the specified refrigeration temperature zone when the heating temperature is high or low, thereby being able to achieve higher refrigeration efficiency, so as to improve the system performance.

[0041] It should be noted that the loop design can realize the recovery of expansion work. While avoiding the adverse effect of expansion work dissipation in the form of heat on system performance, the recovered expansion work can be reused to improve the energy utilization rate of the system.

[0042] In one embodiment of the present invention, Figure 1 As shown, the thermoacoustic engine 110 includes an engine room temperature end heat exchanger 1, an engine reheater 2, an engine hot end heat exchanger 3 and an engine thermal buffer tube 4 which are connected in sequence, the outlet end of the engine thermal buffer tube 4 is connected to the inlet end of the thermoacoustic refrigerator 120, and the inlet end of the acoustic power diversion channel 9 is connected between the outlet end of the engine thermal buffer tube 4 and the inlet end of the thermoacoustic refrigerator 120.

[0043] Optionally, the thermoacoustic refrigerator 120 includes a refrigerator room temperature end heat exchanger 5, a refrigerator reheater 6, a refrigerator cold end heat exchanger 7 and a refrigerator thermal buffer tube 8 connected in sequence, the inlet end of the refrigerator room temperature end heat exchanger 5 is connected to the outlet end of the engine thermal buffer tube 4, and the outlet end of the acoustic power diversion channel 9 is connected to the outlet end of the refrigerator thermal buffer tube 8.

[0044] It can be understood that the heat exchanger 3 at the hot end of the engine absorbs heat from the outside to heat the gas inside it, and the heat exchanger 1 at the room temperature end of the engine is cooled by the refrigerant to maintain the gas inside it at room temperature, thereby generating a certain temperature gradient in the engine regenerator 2. When the temperature gradient exceeds a certain critical value, the thermoacoustic engine undergoes self-excited oscillation due to the thermoacoustic effect, and acoustic work is generated in the thermoacoustic engine 110, and the thermoacoustic engine 110 completes the conversion of thermal energy into acoustic work; at the same time, the acoustic work propagates along the axial direction of the pipeline, and a part of the acoustic work enters the thermoacoustic refrigerator 120. Due to the acoustic cooling effect, part of the acoustic work is consumed in the thermoacoustic refrigerator 120 to obtain cooling capacity; the other part of the acoustic work passes through the acoustic work diversion channel 9, merges with the acoustic work at the outlet of the thermoacoustic refrigerator 120, and enters the entrance of the next thermoacoustic coupling unit 100 or the entrance of the current thermoacoustic coupling unit 100; the acoustic work entering the entrance of the thermoacoustic coupling unit 100 is recovered, and will be amplified again when entering the thermoacoustic engine 110, and the system achieves continuous and stable operation in this reciprocating cycle. It should be noted here that when the low-temperature refrigeration system includes one thermoacoustic coupling unit 100, the entrance of the thermoacoustic coupling unit 100 is the entrance end of the thermoacoustic engine 110 of the thermoacoustic coupling unit 100; when the low-temperature refrigeration system includes multiple thermoacoustic coupling units 100, the entrance of the next thermoacoustic coupling unit 100 is the entrance end of the thermoacoustic engine 110 of the thermoacoustic coupling unit 100 connected to the current thermoacoustic coupling unit 100.

[0045] In this embodiment, the working fluid of the low temperature refrigeration system may be a single gas such as nitrogen, helium, hydrogen, or a gas mixture.

[0046] In one embodiment of the present invention, Figure 4 As shown, a phase adjustment device 11 is provided at the outlet end of the thermoacoustic refrigerator 120. Part of the acoustic power generated by the thermoacoustic engine 110 enters the phase adjustment device 11 through the acoustic power shunt channel 9 to be adjusted to a more reasonable sound field phase, further achieving effective matching of the acoustic field impedance, phase and power flow, so that the thermoacoustic engine 110 and the thermoacoustic refrigerator 120 work in a good traveling wave sound field, achieving efficient energy conversion.

[0047] Optional, such as Figure 4 As shown, the thermoacoustic engine 110 is provided with a pressure wave generator 12 .

[0048] It can be understood that the pressure wave generator 12 can convert external electrical energy into acoustic work; during the startup process or when the system heat energy input is insufficient, the pressure wave generator 12 generates acoustic work to supplement the insufficient acoustic work generated by the thermoacoustic engine 110; and when shutdown is required, the pressure wave generator 12 can generate pressure waves that offset each other with the thermoacoustic engine 110 to achieve rapid vibration shutdown of the system; in this way, by coupling the pressure wave generator 12 with the thermoacoustic engine 110, the start-stop and dynamic response speed of the system can be improved, and the system working state adjustment can be achieved more quickly.

[0049] In this embodiment, the coupling position of the pressure wave generator 12 can be the inlet end of the thermoacoustic engine 110, that is, the pressure wave generator 12 is arranged on the side of the engine room temperature end heat exchanger 1 away from the engine regenerator 2. Of course, in other embodiments, the pressure wave generator 12 can also be arranged in the engine thermal buffer tube 4, or be connected to the engine thermal buffer tube 4 in a bypass manner, that is, the coupling position of the pressure wave generator 12 includes the inside of the engine thermal buffer tube 4 or the refrigerator thermal buffer tube 8 or the bypass.

[0050] It should be noted that when the coupling position of the pressure wave generator 12 is inside the refrigerator thermal buffer tube 8, the loop acoustic DC formed by the thermoacoustic refrigerator 120 and the acoustic power diversion channel 9 can be isolated, eliminating the additional loss of DC, so that more acoustic power can be effectively utilized in the refrigeration process, effectively improving the efficiency and performance of the system.

[0051] It should be noted that the pressure wave generator 12 may also be provided in the thermoacoustic refrigerator 120 , and the pressure wave generator 12 may also be provided in both the thermoacoustic engine 110 and the thermoacoustic refrigerator 120 .

[0052] In one embodiment of the present invention, Figure 8 As shown, the outlet of the thermoacoustic refrigerator 120 is provided with a work-to-electricity conversion device 13. When the system does not need pressure wave assistance, the work-to-electricity conversion device 13 is used for mechanical phase modulation; when the system needs pressure wave assistance, the work-to-electricity conversion device 13 is used to generate auxiliary pressure waves.

[0053] It can be understood that the work-to-electricity conversion device 13 can realize the functions of the phase-adjusting device 11 and the pressure wave generator 12, and the work-to-electricity conversion device 13 can use a linear motor or a liquid metal magnetohydrodynamic engine to realize related functions. Specifically, when the system operates normally without the need for input pressure wave assistance, the work-to-electricity conversion device 13 only exhibits the function of the mechanical phase-adjusting device 11, and because the acoustic work drives the mover to move during the phase adjustment process, the work-to-electricity conversion device 13 can output electrical energy to the outside; when external pressure fluctuations are required to assist the system in regulation (such as the start-stop process), the work-to-electricity conversion device 13 uses external electrical energy to generate auxiliary pressure waves. It should be noted here that the work-to-electricity conversion device 13 of this embodiment can realize the functions of the phase-adjusting device 11 and the pressure wave generator 12, making the system less complex and more compact.

[0054] In one embodiment of the present invention, there are multiple thermoacoustic coupling units 100, and the multiple thermoacoustic coupling units 100 are connected end to end; preferably, the multiple thermoacoustic coupling units 100 have the same structure.

[0055] For example, the low-temperature refrigeration system includes three thermoacoustic coupling units 100 connected end to end, realizing thermoacoustic driven low-temperature refrigeration of the three thermoacoustic coupling units 100, and the outlet of each thermoacoustic coupling unit 100 is provided with a phase adjustment device 11, so the thermoacoustic coupling units 100 are connected through the phase adjustment device 11, and the phase adjustment device 11 can realize effective adjustment of the sound field, so that the thermoacoustic engine 110 and the thermoacoustic refrigerator 120 work in a good traveling wave sound field, and realize efficient energy conversion. It should be noted that the thermoacoustic coupling unit 100 can also be two, four or other numbers.

[0056] like Figure 5 As shown, the phase adjustment device 11 may be an acoustic phase adjustment device, three thermoacoustic coupling units 100 are arranged side by side, and two adjacent thermoacoustic coupling units 100 are connected via the acoustic phase adjustment device.

[0057] The phase-adjusting device 11 may also be a mechanical phase-adjusting device, which may be a liquid phase-adjusting device or a solid phase-adjusting device. Figure 6 As shown, three thermoacoustic coupling units 100 are arranged in a triangle, and two adjacent thermoacoustic coupling units 100 are connected by a liquid phase adjustment device, and the solid phase adjustment device can be a U-shaped tubular structure. Figure 7 As shown, two adjacent thermoacoustic coupling units 100 are connected via a solid phase adjustment device; it should be noted here that when there are two thermoacoustic coupling units 100, the two thermoacoustic coupling units 100 are symmetrically arranged; when there are four or other numbers of thermoacoustic coupling units 100, they can be arranged in other polygons such as quadrilaterals.

[0058] It should be noted that the phase adjustment device 11 adopts an acoustic phase adjustment device, which can achieve no moving parts at all and improve the long-term stability and reliability of the system. The phase adjustment device 11 adopts a mechanical phase adjustment device, which is small in size and can isolate the acoustic direct current in the entire loop, which can reduce useless energy loss and enable more energy to be effectively used for the cooling function; in addition, the three thermal-acoustic coupling units 100 are arranged in a triangle, which can make the vibrations between the units cancel each other, thereby reducing the vibration amplitude of the entire system.

[0059] In one embodiment of the present invention, the low-temperature refrigeration system further includes a temperature measuring element (not shown in the figure) and a controller. The temperature measuring element is arranged at the cold end heat exchanger 7 of the refrigerator, and the controller is connected to the temperature measuring element and the control element 10 respectively.

[0060] It can be understood that the control component 10 is a control valve arranged in the acoustic power diversion channel 9. The temperature measuring element obtains the current temperature of the cold end heat exchanger 7 of the refrigerator. The controller controls the opening of the control valve based on the current temperature and the preset temperature to adjust the conductance of the acoustic power diversion channel 9 to meet the requirements of different diversion volumes for different temperatures.

[0061] Specifically, under the same cooling capacity, if the current temperature is lower than the preset temperature, the controller controls the control valve opening to increase or decrease, and controls the conductance of the acoustic power diversion channel 9 to decrease through the control component 10 to reduce the acoustic power diversion amount; under the same cooling capacity, if the current temperature is higher than the preset temperature, the controller controls the control valve opening to increase, and controls the conductance of the acoustic power diversion channel 9 to increase through the control component 10 to increase the acoustic power diversion amount, so that the control valve can adjust the acoustic power diversion amount at any time, so that the system can always operate at the most efficient state at different heating temperatures or cooling temperatures.

[0062] In other embodiments, the cold end heat exchanger 7 of the refrigerator is provided with a cold capacity measuring device, which is electrically connected to the controller. The cold capacity measuring device obtains the current cooling capacity of the cold end heat exchanger 7 of the refrigerator. The controller controls the opening of the control valve based on the current cooling capacity and the preset cooling capacity to adjust the conductance of the acoustic power diversion channel 9 to meet the requirements of different diversion volumes for different temperatures.

[0063] Specifically, at the same temperature, if the current cooling capacity is less than the preset cooling capacity, the controller controls the control valve to increase the opening, so that the conductance of the acoustic power diversion channel 9 increases to increase the acoustic power diversion amount; At the same temperature, if the current cooling capacity is greater than the preset cooling capacity, the controller controls the control valve opening to increase or decrease, so that the conductance of the acoustic power diversion channel 9 is reduced to reduce the acoustic power diversion amount, so that the control valve can adjust the acoustic power diversion amount at any time, so that the system can always operate at the most efficient state at different heating temperatures or cooling temperatures.

[0064] In one embodiment of the present invention, Fig. 9 As shown, the low-temperature refrigeration system can utilize thermal energy and electrical energy, and the outlet end of the thermoacoustic refrigerator 120 is connected to the inlet end of the thermoacoustic engine 110 through a driving mechanism; specifically, the driving mechanism includes two pistons, the two pistons are a compression piston 14 and an expansion piston 15, the compression piston 14 is connected to the inlet end of the thermoacoustic engine 110, and the expansion piston 15 is connected to the outlet end of the thermoacoustic refrigerator 120, the two pistons are connected by a mechanical structure, and there is a certain motion phase.

[0065] It is understandable that the bypass refrigeration principle is integrated into the α-type Stirling refrigerator to form an efficient low-temperature refrigeration system that utilizes thermal energy and electrical energy. The piston movement is driven by external electricity, causing the system to generate acoustic mechanical energy; at the same time, the engine part can also absorb thermal energy to generate mechanical energy. Since the system is driven by two external energies, thermal energy and electrical energy, the system can achieve long-term stable operation. It should be noted that the introduction of the acoustic power diversion component 130 can save the input of external electrical energy or thermal energy as needed, thereby achieving the purpose of energy saving.

[0066] In another embodiment of the present invention, Fig.10 As shown, the low-temperature refrigeration system can utilize thermal energy and electrical energy, and the outlet end of the thermoacoustic refrigerator 120 is connected to the inlet end of the thermoacoustic engine 110 through a driving mechanism; specifically, the driving mechanism includes a displacer 16 and a power piston 17 connected in sequence, and the displacer 16 is close to the outlet end of the thermoacoustic refrigerator 120.

[0067] It is understandable that the bypass refrigeration principle is integrated into the β-type Stirling refrigerator to form an efficient low-temperature refrigeration system that utilizes thermal energy and electrical energy. The power piston 17 is driven by external electricity to move, causing the system to generate acoustic mechanical energy; at the same time, the engine part can also absorb thermal energy to generate mechanical energy. Since the system is driven by two external energies, thermal energy and electrical energy, the system can achieve long-term stable operation. It should be noted that the introduction of the acoustic power diversion component 130 can save the input of external electrical energy or thermal energy to a certain extent, thereby achieving the purpose of energy saving.

[0068] Based on the low-temperature refrigeration system using thermal energy provided in any of the above embodiments, an embodiment of the second aspect of the present invention provides a control method for a low-temperature refrigeration system using thermal energy, including the following contents: When the acoustic power generated by the thermoacoustic engine 110 does not match the acoustic power consumed by the thermoacoustic refrigerator 120, the control component 10 controls the acoustic power shunt channel 9 to be turned on, so that part of the acoustic power generated by the thermoacoustic engine 110 enters the outlet end of the thermoacoustic refrigerator 120 through the acoustic power shunt channel 9.

[0069] It can be understood that, when the acoustic power generated by the thermoacoustic engine 110 does not match the acoustic power consumed by the thermoacoustic refrigerator 120, the control component 10 controls the acoustic power diversion channel 9 to be turned on, so as to divert the acoustic power at the outlet of the thermoacoustic engine 110 so that it is not consumed by the thermoacoustic refrigerator 120 but directly enters the inlet end of the thermoacoustic engine 110 for recovery, so as to achieve the matching of the acoustic power generated by the thermoacoustic engine 110 and the acoustic power consumed by the thermoacoustic refrigerator 120, thereby achieving a larger cooling capacity and a higher cooling efficiency, so that the system can efficiently work in the specified cooling temperature zone when the heating temperature is high or low.

[0070] Optionally, when the acoustic power generated by the thermoacoustic engine 110 does not match the acoustic power consumed by the thermoacoustic refrigerator 120, the control element 10 controls the acoustic power diversion channel 9 to be turned on, specifically including the following contents: The current temperature of the refrigerator cold end heat exchanger 7 of the thermoacoustic refrigerator 120 is obtained, and the matching between the acoustic power generation of the thermoacoustic engine 110 and the acoustic power consumption of the thermoacoustic refrigerator 120 is determined based on the current temperature and the preset temperature; under the same cooling capacity, if the current temperature is lower than the preset temperature, the conductance of the acoustic power shunt channel 9 is controlled to decrease through the control component 10; under the same cooling capacity, if the current temperature is higher than the preset temperature, the conductance of the acoustic power shunt channel 9 is controlled to increase through the control component 10.

[0071] It should be noted that the current cooling capacity of the refrigerator cold end heat exchanger 7 of the thermoacoustic refrigerator 120 can also be obtained, and the matching between the acoustic power generation of the thermoacoustic engine 110 and the acoustic power consumption of the thermoacoustic refrigerator 120 can be judged based on the current cooling capacity and the preset cooling capacity; at the same temperature, if the current cooling capacity is greater than the preset cooling capacity, the conductance of the acoustic power diversion channel 9 is controlled to decrease through the control component 10; at the same temperature, if the current cooling capacity is less than the preset cooling capacity, the conductance of the acoustic power diversion channel 9 is controlled to increase through the control component 10.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A low temperature refrigeration system utilizing thermal energy, characterized in that: It comprises a thermoacoustic coupling unit (100), wherein the thermoacoustic coupling unit (100) comprises: Thermoacoustic engines (110); A thermoacoustic refrigerator (120), wherein the inlet end of the thermoacoustic refrigerator (120) is connected to the outlet end of the thermoacoustic engine (110), and the outlet end of the thermoacoustic refrigerator (120) is connected to the inlet end of the thermoacoustic engine (110); An acoustic power shunt component (130) comprises an acoustic power shunt channel (9) and a control element (10), wherein the acoustic power shunt channel (9) is connected between an inlet end of the thermoacoustic refrigerator (120) and an outlet end of the thermoacoustic refrigerator (120), and the control element (10) is arranged in the acoustic power shunt channel (9), and the control element (10) is used to control the disconnection, conduction and opening degree of the acoustic power shunt channel (9).

2. The low temperature refrigeration system using thermal energy according to claim 1, characterized in that: A phase adjustment device (11) is provided at the outlet end of the thermoacoustic refrigerator (120).

3. The low temperature refrigeration system using thermal energy according to claim 2, characterized in that: The thermoacoustic engine (110) and / or the thermoacoustic refrigerator (120) is provided with a pressure wave generator (12).

4. The low temperature refrigeration system using thermal energy according to claim 3, characterized in that: The thermoacoustic engine (110) comprises an engine room temperature end heat exchanger (1), an engine regenerator (2), an engine hot end heat exchanger (3) and an engine thermal buffer tube (4) which are connected in sequence, and the engine thermal buffer tube (4) is connected to the inlet end of the thermoacoustic refrigerator (120); The pressure wave generator (12) is arranged inside the engine heat buffer tube (4) or is connected to the engine heat buffer tube (4) in a bypass manner, or is arranged on a side of the engine room temperature end heat exchanger (1) away from the engine regenerator (2).

5. The low temperature refrigeration system using thermal energy according to claim 1, characterized in that: The outlet end of the thermoacoustic refrigerator (120) is provided with a work-electricity conversion device (13). When the system does not require pressure wave assistance, the work-electricity conversion device (13) is used for mechanical phase modulation; when the system requires pressure wave assistance, the work-electricity conversion device (13) is used to generate auxiliary pressure waves.

6. The low temperature refrigeration system using thermal energy according to any one of claims 2 to 5, characterized in that: There are a plurality of the thermoacoustic coupling units (100), and the plurality of the thermoacoustic coupling units (100) are connected end to end.

7. The low temperature refrigeration system using thermal energy according to claim 6, characterized in that: The phase modulation device (11) is one of an acoustic phase modulation device, a liquid phase modulation device, and a solid phase modulation device.

8. The low temperature refrigeration system using thermal energy according to claim 6, characterized in that: It also includes a temperature measuring element and a controller, and the thermoacoustic refrigerator (120) includes a refrigerator cold end heat exchanger (7); The temperature measuring element is arranged on the cold end heat exchanger (7) of the refrigerator, and the controller is connected to the temperature measuring element and the control element (10) respectively.

9. A control method for a low temperature refrigeration system using thermal energy as claimed in any one of claims 1 to 8, characterized in that: include: When the acoustic power generated by the thermoacoustic engine (110) does not match the acoustic power consumed by the thermoacoustic refrigerator (120), the control element (10) controls the acoustic power shunt channel (9) to be open, so that part of the acoustic power generated by the thermoacoustic engine (110) enters the outlet end of the thermoacoustic refrigerator (120) through the acoustic power shunt channel (9).

10. The control method of a low temperature refrigeration system using thermal energy according to claim 9, characterized in that: When the acoustic power generated by the thermoacoustic engine (110) does not match the acoustic power consumed by the thermoacoustic refrigerator (120), controlling the acoustic power diversion channel (9) to be conductive through the control element (10) comprises: Obtaining the current temperature or current cooling capacity of a refrigerator cold end heat exchanger (7) of a thermoacoustic refrigerator (120); When the current temperature is lower than the preset temperature or the current cooling capacity is higher than the preset cooling capacity, the conductance of the acoustic power diversion channel (9) is controlled to decrease by the control element (10); When the current temperature is greater than the preset temperature or the current cooling capacity is less than the preset cooling capacity, the conductance of the acoustic power split channel (9) is controlled to increase through the control element (10).

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