Elastic heat refrigerating system and circulating method

Abstract

The invention relates to the field of elastic-thermal refrigeration, in particular to an elastic-thermal refrigeration system and a circulation method.The elastic-thermal refrigeration system comprises an elastic-thermal coupling module, and the elastic-thermal coupling module is composed of a driving set, a refrigeration set and a mechanical coupling device connecting the driving set and the refrigeration set together; the thermal cycle module acts on the elastic-thermal coupling module; the heat circulation module comprises a heat transfer unit for conducting heat transfer on the driving set, a heat dissipation unit for conducting heat dissipation on the driving set and a heat exchange unit acting on the refrigeration set, two sets of driving memory alloy and one set of refrigeration memory alloy are ingeniously combined, and a tension-torsion coupled elastic heat refrigeration mode is achieved; on the one hand, the specific surface area of the elastic heat material can be increased based on the multi-rod structural design, the heat transfer and heat exchange effect is improved, on the other hand, the composite deformation mode can endow the elastic heat material with more sufficient phase change during loading, and the unit volume refrigeration power of the system can be improved.

Description

Technical Field

[0001] The present invention relates to the field of calorific value refrigeration, and in particular to an calorific value refrigeration system and a circulation method. Background Art

[0002] Refrigeration technology is an indispensable component of many fields, including modern life, industrial production, and scientific research. Currently, space cooling applications, dominated by vapor compression refrigeration technology, account for 25% to 30% of global energy consumption. In addition, refrigeration and air-conditioning equipment contributes more than 7.8% to global greenhouse gas emissions, of which approximately 30% is caused by the use of hydrofluorocarbon refrigerants (whose global warming potential (GWP) is thousands of times that of CO2). Therefore, in the context of global warming, it is crucial to develop new, green and efficient refrigeration technologies with low energy consumption and low / zero global warming potential (GWP).

[0003] Among them, solid-state refrigeration technology based on material field-induced phase change heat absorption is becoming a key direction of current refrigeration technology development due to its high efficiency and zero pollution characteristics.

[0004] However, given that nickel-titanium (NiTi) shape memory alloys themselves have a high critical stress for phase transition, existing elastic-caloric cooling devices often rely on complex and bulky mechanical drive mechanisms, which not only limits the cooling power per unit volume of the overall device, but also reduces energy efficiency. It is worth noting that nickel-titanium shape memory alloys based on the shape memory effect can be developed into a type of thermal actuator for intelligent control. Compared with traditional hydraulic and motor actuators, nickel-titanium shape memory alloy actuators have the advantages of compatible load-bearing and driving capabilities, high energy density (over 10 J / cm 3 , about 25 times that of traditional motors) and environmental perception capabilities, and can perfectly match the driving characteristics required by the elastic-caloric device, such as large drive and small stroke.

[0005] Based on the proposal of using the driving group memory alloy to realize the cyclic loading and unloading process of the refrigeration group memory alloy, we also need to further pay attention to the combination configuration, driving mode and manufacturing process between different effect memory alloys. Therefore, we proposed an elastic caloric refrigeration system and circulation method. Summary of the Invention

[0006] Therefore, the technical problem to be solved by the present invention is: to significantly simplify the driving mechanism and improve the cooling power per unit volume, while effectively realizing the multifunctional integration of self-driving and elastic thermal cooling and its material-structure-function integrated forming and preparation.

[0007] The above technical problems are solved by the following technical solution: The present invention proposes an elastic thermal refrigeration system, which includes an elastic thermal coupling module, which is composed of a drive group, a refrigeration group, and a mechanical coupling device connecting the drive group and the refrigeration group together; a thermal circulation module, which acts on the elastic thermal coupling module; the thermal circulation module includes a heat transfer unit for transferring heat to the drive group, a heat dissipation unit for dissipating heat from the drive group, and a heat exchange unit acting on the refrigeration group.

[0008] In a preferred embodiment of the elastic caloric refrigeration system of the present invention: the heat transfer unit is composed of a heat source, a first valve, a second valve and a first circulation pump, and acts on the drive group; the heat source can transfer heat to the drive group through the first valve, the second valve and the first circulation pump.

[0009] In a preferred embodiment of the elastic caloric refrigeration system of the present invention: the heat dissipation unit is composed of a first normal-temperature heat sink, a third valve, a fourth valve, and a second circulating pump connected together, and acts on the drive group; the fluid in the first normal-temperature heat sink can flow through the drive group to dissipate heat under the drive of the second circulating pump.

[0010] In a preferred embodiment of the elastic caloric refrigeration system of the present invention: the heat exchange unit includes a heat exhaust circuit and a heat absorption circuit, and the heat exhaust circuit and the heat absorption circuit both include a piston, one end of the piston is connected to a second normal temperature heat sink, and the other end of the piston is connected to a low temperature heat sink.

[0011] In a preferred embodiment of the elastic caloric refrigeration system of the present invention: the heat rejection circuit further includes a fifth valve connected to the second normal-temperature heat sink, and a seventh valve connected to the low-temperature heat sink; the heat absorption circuit further includes a sixth valve connected to the second normal-temperature heat sink, and an eighth valve connected to the low-temperature heat sink.

[0012] In a preferred embodiment of the elastic-caloric refrigeration system of the present invention: when the starting piston moves in a first direction, the fluid of the low-temperature heat sink flows through the seventh valve, the refrigeration group, and the fifth valve to the second normal-temperature heat sink for heat dissipation; when the starting piston moves in a second direction opposite to the first direction, the fluid of the second normal-temperature heat sink flows through the sixth valve, the refrigeration group, and the eighth valve to the low-temperature heat sink for heat absorption.

[0013] In a preferred embodiment of the caloric refrigerant system of the present invention: the driving group is composed of a chiral pressed torsion structure of a nickel-titanium memory alloy that is in a completely martensitic state at room temperature and zero stress; the refrigeration group is composed of a chiral pressed torsion structure of a nickel-titanium memory alloy that is in a completely austenitic state at room temperature and zero stress.

[0014] In a preferred embodiment of the elastic-caloric refrigeration system of the present invention: two drive groups are provided, one end of the drive group is connected to the refrigeration group via a mechanical coupling device, and the drive group is fixed to the frame; internal flow channels are provided inside both ends of the drive group and the refrigeration group to establish a fluid path connection with the thermal cycle module.

[0015] The above technical problems are solved by the following technical solutions: The present invention proposes a circulation method, which includes providing heat to the driving group through a heat transfer unit, so that the driving group transforms from the martensite phase to the austenite phase and generates a driving force; using the driving force generated by the driving group, the refrigeration group is subjected to tensile-torsion coupling loading through a mechanical coupling device, so that the refrigeration group transforms from the austenite phase to the martensite phase, thereby achieving a refrigeration effect; and, the piston drives the fluid to flow from the low-temperature heat sink to the second normal-temperature heat sink, taking away the heat released by the refrigeration group; the heat dissipation unit is connected to the driving group, so that the driving group dissipates heat and reversely transforms from the austenite phase to the martensite phase, and the refrigeration group is unloaded through a mechanical coupling device; the refrigeration group is restored from the martensite phase to the austenite phase through the unloading action of the driving group; and, the piston drives the fluid to flow from the second normal-temperature heat sink to the low-temperature heat sink, absorbs heat, and completes a refrigeration cycle.

[0016] In a preferred embodiment of the circulation method of the present invention: when heating the driving group, the heat temperature provided by the heat transfer unit is higher than the austenite termination temperature of the driving group; when dissipating the driving group, the fluid temperature provided by the first constant temperature heat sink is lower than the martensite termination temperature of the driving group.

[0017] The beneficial effects of the present invention are: based on the 4D printing process, by regulating the laser input energy density, the rapid forming and multi-effect coupling of isotropic chiral multi-rod memory alloys are realized, avoiding the traditional process of relying on the formulation of memory alloys with different Ni contents to achieve different functional characteristics. The technical approach effectively shortens the process cycle and improves the utilization rate and use efficiency of materials; not only that, but also proposes an elastic-caloric refrigeration system, and by cleverly combining two groups of driving memory alloys and a group of refrigeration memory alloys, a tension-torsion coupled elastic-caloric refrigeration mode is realized. On the one hand, the specific surface area of ​​the elastic-caloric material can be increased based on the multi-rod structure design, and the heat transfer and heat exchange effect can be improved. On the other hand, the composite deformation method can give the elastic-caloric material a more sufficient phase change when loaded, which helps to improve the system's unit volume cooling power. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings of the embodiments of the present invention. Obviously, the drawings described below only relate to some embodiments of the present invention and are not intended to limit the present invention. Among them:

[0019] Figure 1 The diagram shows the mechanism of preparing isotropic memory alloy based on 4D printing;

[0020] Figure 2 A schematic diagram of pre-training and constraint aging processing of the driving group is shown;

[0021] Figure 3 A schematic diagram showing heating of the drive group based on a heat transfer unit is shown;

[0022] Figure 4 A schematic diagram showing the heat transfer unit driving the drive group, and the mechanical coupling device performing compression-torsion coupling loading on the refrigeration group and heat dissipation under the action of the piston;

[0023] Figure 5 A schematic diagram showing the cooling and recovery of the drive group based on a normal temperature heat sink is shown;

[0024] Figure 6 A schematic diagram shows the cooling and recovery of the drive group based on a normal temperature heat sink, and the unloading of the refrigeration group under the action of a mechanical coupling device and the absorption of heat by the piston. DETAILED DESCRIPTION

[0025] In order to enable those skilled in the art to better understand the present invention, the present invention is further described in detail below with reference to specific embodiments and the accompanying drawings.

[0026] The terms used in the present invention are those commonly used in the art in view of the functions of the present invention, but these terms may vary according to the intentions of those skilled in the art, precedents, or new technologies in the art. In addition, specific terms may be selected by the applicant, and in such cases, their detailed meanings will be described in the detailed description of the present invention. Therefore, the terms used in the specification should not be understood as simple names, but rather as the meanings of the terms and the overall description of the present invention.

[0027] Reference Figures 1 to 6 This embodiment provides an elastic-thermal cooling system, including an elastic-thermal coupling module 1, which is composed of a drive group 11, a cooling group 12, and a mechanical coupling device 13 connecting the drive group 11 and the cooling group 12; a thermal circulation module 2, which acts on the elastic-thermal coupling module 1; the thermal circulation module 2 includes a heat transfer unit 21 for transferring heat to the drive group 11, a heat dissipation unit 22 for dissipating heat from the drive group 11, and a heat exchange unit 23 for acting on the cooling group 12.

[0028] The driving group 11 is a chiral multi-rod memory alloy driving group; the cooling group 12 is a chiral multi-rod memory alloy cooling group 12; specifically, the driving group 11 is made of nickel-titanium alloy through a 4D printing process, pre-training and mechanical constraint aging treatment, and the cooling group 12 is directly made of nickel-titanium alloy through a 4D printing process.

[0029] Combine Figure 1 and Figure 2 The 4D printing process mainly includes the following steps: 3D solid modeling, path planning, slicing, layer-by-layer powder spreading and laser scanning curing. Among them, the layer thickness of the layer-by-layer powder spreading is set to 30μm. The main process parameters of laser scanning curing include: laser power between 100~150W, scanning speed between 400~1200mm / s, and scanning spacing of 50μm. For the chiral multi-rod memory alloy drive group, the laser body energy density of 4D printing is controlled at 155.55-233.33J / mm 3 For the chiral multi-rod memory alloy refrigeration group, the laser body energy density is controlled at 55.55-73.33J / mm 3 In addition, laser scanning curing uses a combination of raster scanning and interlayer scanning vector rotation, with the interlayer rotation angle set between 45° and 90°. The laser scanning curing process also involves substrate preheating, with the preheating temperature set at 200°C.

[0030] Further, if Figure 1 As shown in the figure, by regulating the laser input energy density during 4D printing, the Ni evaporation amount, internal dislocation density and residual stress during the forming process can be effectively regulated, thereby achieving the regulation of the phase transition temperature. For the driving group, it is required to have a room temperature shape memory effect, that is, the martensite phase transformation termination temperature (Mf) is higher than room temperature; while for the cooling group, it is required to have room temperature superelasticity, that is, the austenite phase transformation termination temperature (Af) is lower than room temperature. At low laser energy (55.55-73.33J / mm 3 ) input, the material tends to exhibit room temperature superelasticity; while at high laser energy (155.55-233.33J / mm 3 ) input, the material is more likely to exhibit room temperature shape memory effect. In order to achieve the excellent bidirectional memory effect of the chiral multi-rod memory alloy drive group, that is, to achieve reversible thermal drive of high temperature shape and low temperature shape, it is necessary to perform necessary training and heat treatment, such as Figure 2As shown, before heat treatment, the chiral multi-rod memory alloy is first subjected to cyclic loading and unloading on a universal testing machine, with the loading displacement being 50% of the overall structure height. After each unloading, the alloy is heated and restored to its initial state, and the cycle is repeated for no less than 10 times. The pre-trained specimen is mechanically constrained in an unloaded and unheated state, and then subjected to aging treatment, with the aging temperature controlled at 350-550°C and the aging time controlled at 0.5-1 hour.

[0031] As an optional embodiment, the heat transfer unit 21 is composed of a heat source 211, a first valve 212, a second valve 213 and a first circulation pump 214, and acts on the drive group 11; the heat source 211 transfers heat to the drive group 11 through the first valve 212, the second valve 213 and the first circulation pump 214 at the same time, such as Figure 3 As shown, the internal temperature of the drive group 11 gradually increases and exceeds its martensitic phase transition temperature Mf, inducing a phase transition. However, due to the constraints of the mechanical coupling device 13 and the frame 14, the refrigeration group 12 has not yet undergone substantial displacement. It should be noted that the heat source 211 is preferably a low-grade heat source (such as waste heat from a car engine).

[0032] As the temperature inside the driving group 11 continues to rise, the phase change process accelerates, the driving group 11 undergoes a suppressed torsion effect and transforms into its high-temperature state. Under the action of the mechanical coupling device 13, the chiral multi-rod memory alloy refrigeration group 11 undergoes a combined deformation of torsion and stretching, such as Figure 4 As shown, when the maximum deformation is reached, the upper and lower chiral multi-rod memory alloy drive groups 11 completely recover to the high-temperature state.

[0033] Open the fifth valve 2311 and the seventh valve 2312 and start the piston 233 to move in the first direction, that is, as shown in the figure, the first direction is downward movement. At this time, the low-temperature heat sink 2332, that is, the fluid in the low-temperature refrigeration space flows through the seventh valve 2312, the refrigeration group 12, and the fifth valve 2311 to the second normal-temperature heat sink 2331 for heat dissipation, thereby reducing the temperature of the chiral multi-rod memory alloy refrigeration group 12.

[0034] As the temperature of the chiral multi-rod memory alloy refrigeration group 12 approaches the temperature of the low-temperature heat sink 2332, the fifth valve 2311 and the seventh valve 2312 are closed, the first valve 212, the second valve 213 and the first circulation pump 214 of the upper and lower heat transfer units 21 are closed, and the third valve 222, the fourth valve 223 and the second circulation pump 224 are opened. Figure 5 As shown, at this time, the fluid in the first normal temperature heat sink 221 flows through the corresponding drive group 11 under the drive of the second circulation pump 224, cools itself down and dissipates heat to the first normal temperature heat sink 221.

[0035] It is to be noted that the drive group 11 is provided with two upper and lower ones, and the heat transfer unit 21 and the heat dissipation unit 22 are also provided with two groups, one to one corresponding to the drive group 11, as shown in FIG. Figure 3 shown.

[0036] As the internal temperature of the chiral multi-rod memory alloy driving group 11 continues to drop, the reverse martensitic phase transformation occurs, and the driving group 12 then undergoes a reverse compression torsion effect and transforms into a low-temperature state. Under the action of the mechanical coupling device 13, the chiral multi-rod memory alloy refrigeration group 12 is unloaded.

[0037] When the chiral multi-rod memory alloy refrigeration group 12 is unloaded, the sixth valve 2321 and the eighth valve 2322 are opened and the piston 233 is started to move in a second direction opposite to the first direction, that is, upward movement. Figure 6 As shown, at this time, the fluid in the second normal temperature heat sink 23318 flows to the low temperature heat sink 2332 through the sixth valve 2321, the refrigeration group 12, and the eighth valve 2322 to absorb heat and cool, completing a cycle.

[0038] As an optional embodiment, the driving group 11 is composed of a chiral pressed torsion structure of a nickel-titanium memory alloy that is in a completely martensitic state at room temperature and zero stress; the refrigeration group 12 is composed of a chiral pressed torsion structure of a nickel-titanium memory alloy that is in a completely austenitic state at room temperature and zero stress.

[0039] As an optional embodiment, two drive groups 11 are provided, one end of the drive group 11 is connected to the refrigeration group 12 through a mechanical coupling device 13, and the drive group 11 is fixed on the frame 14; internal flow channels are provided inside both ends of the drive group 11 and the refrigeration group 12 to connect the fluid passage with the thermal cycle module 2.

[0040] Reference Figures 3 to 5 , describes the thermal cycle network of the caloric refrigeration system and its working status at different stages. This embodiment also provides a circulation method, including:

[0041] Heat is provided to the driving group 11 through the heat transfer unit 21, causing the driving group 11 to transform from the martensite phase to the austenite phase and generate a driving force. That is, the two driving groups 11 of the chiral multi-rod memory alloy in a completely martensite state at room temperature and zero stress are simultaneously heated by a low-grade heat source 211 with a temperature T1 higher than its austenite termination temperature Af. Under the action of the high-temperature heat flow, they transform into austenite and provide the driving force required for loading to the chiral multi-rod memory alloy refrigeration group 12 through the mechanical coupling device 13.

[0042] By utilizing the driving force generated by the drive group 11, the refrigeration group 12 is subjected to tensile-torsional coupling loading through the mechanical coupling device 13, so that the refrigeration group 12 is transformed from the austenite phase to the martensite phase to achieve a refrigeration effect; and, the piston 233 drives the fluid to flow from the low-temperature heat sink 2332 to the second normal-temperature heat sink 2331, taking away the heat released by the refrigeration group 12; that is, under the action of compression-torsion coupling, as shown in the figure, the upper chiral multi-rod memory alloy drive group 11 is shortened counterclockwise, while the lower chiral multi-rod memory alloy drive group 11 is shortened clockwise. As a result, the chiral multi-rod memory alloy refrigeration group 12, which is in a completely austenitic state at room temperature and zero stress, undergoes tensile-torsional coupling deformation under the action of the mechanical coupling device 13 and is loaded to transform into martensite; subsequently, driven by the piston 233, the fluid flows from the low-temperature heat sink 2332 through the deformed chiral multi-rod memory alloy refrigeration group 12 to the second normal-temperature heat sink 2331 and dissipates heat.

[0043] The heat dissipation unit 22 is connected to the driving group 11, so that the driving group 11 dissipates heat and reversely transforms from the austenite phase to the martensite phase, and unloads the refrigeration group 12 through the mechanical coupling device 13; after loading is completed, the chiral multi-rod memory alloy driving group 11 in the austenite state simultaneously dissipates heat to the first normal-temperature heat sink 221 with a temperature T2 lower than its martensite termination temperature Mf, reversely transforms into martensite under the action of the low-temperature fluid, and unloads the chiral multi-rod memory alloy refrigeration group 12 through the mechanical coupling device 13.

[0044] Through the unloading action of the driving group 11, the refrigeration group 12 is restored from the martensite phase to the austenite phase; and, through the piston 233, the fluid is driven to flow from the second normal temperature heat sink 2331 to the low temperature heat sink 2332 to absorb heat and complete a refrigeration cycle; that is, after the heat dissipation is completed, the chiral multi-rod memory alloy refrigeration group 12 in the martensite state is unloaded by the chiral multi-rod memory alloy driving group 11 through the mechanical coupling device 13, thereby being transformed into austenite; subsequently, driven by the piston 233, the fluid flows from the second normal temperature heat sink 2331 to the low temperature heat sink 2332 via the unloaded refrigeration group 12 and absorbs heat for refrigeration.

[0045] Finally, it should be pointed out that the methods and devices described in detail above are merely embodiments, and those skilled in the art can modify these embodiments in different ways without departing from the scope of the present invention.

Claims

1. A calorific cooling system, characterized in that: A thermoelastic coupling module (1), the thermoelastic coupling module (1) comprising a drive group (11), a refrigeration group (12), and a mechanical coupling device (13) connecting the drive group (11) and the refrigeration group (12); A heat circulation module (2) acts on the elastic-thermal coupling module (1); the heat circulation module (2) includes a heat transfer unit (21) for transferring heat to the drive group (11), a heat dissipation unit (22) for dissipating heat from the drive group (11), and a heat exchange unit (23) acting on the refrigeration group (12).

2. The elastic caloric refrigeration system according to claim 1, characterized in that: The heat transfer unit (21) is composed of a heat source (211), a first valve (212), a second valve (213) and a first circulation pump (214), and acts on the drive group (11); the heat source (211) can transfer heat to the drive group (11) through the first valve (212), the second valve (213) and the first circulation pump (214).

3. The elastic caloric refrigeration system according to claim 2, characterized in that: The heat dissipation unit (22) is composed of a first constant-temperature heat sink (221), a third valve (222), a fourth valve (223) and a second circulation pump (224), and acts on the drive group (11); the fluid in the first constant-temperature heat sink (221) can flow through the drive group (11) to dissipate heat under the drive of the second circulation pump (224).

4. The elastic caloric refrigeration system according to claim 1, characterized in that: The heat exchange unit (23) comprises a heat dissipation circuit (231) and a heat absorption circuit (232), wherein the heat dissipation circuit (231) and the heat absorption circuit (232) both comprise a piston (233), one end of the piston (233) is connected to a second normal-temperature heat sink (2331), and the other end of the piston (233) is connected to a low-temperature heat sink (2332).

5. The elastic caloric refrigeration system according to claim 4, characterized in that: The heat exhaust circuit (231) further includes a fifth valve (2311) connected to the second normal-temperature heat sink (2331), and a seventh valve (2312) connected to the low-temperature heat sink (2332); The heat absorption circuit (232) further includes a sixth valve (2321) connected to the second normal-temperature heat sink (2331), and an eighth valve (2322) connected to the low-temperature heat sink (2332).

6. The elastic caloric refrigeration system according to claim 5, characterized in that: When the starting piston (233) moves in the first direction, the fluid in the low-temperature heat sink (2332) flows through the seventh valve (2312), the refrigeration group (12), and the fifth valve (2311) to the second normal-temperature heat sink (2331) for heat dissipation; When the starting piston (233) moves in a second direction opposite to the first direction, the fluid in the second normal temperature heat sink (2331) flows through the sixth valve (2321), the refrigeration group (12), and the eighth valve (2322) to the low temperature heat sink (2332) to absorb heat.

7. The elastic caloric refrigeration system according to any one of claims 1 to 3 and 6, characterized in that: The driving group (11) is composed of a nickel-titanium memory alloy chiral pressed torsion structure in a completely martensitic state at room temperature and zero stress; The refrigeration group (12) is composed of a nickel-titanium memory alloy chiral pressed torsion structure in a completely austenitic state at room temperature and in a zero-stress state.

8. The elastic caloric refrigeration system according to claim 7, characterized in that: Two drive groups (11) are provided, one end of the drive group (11) is connected to the refrigeration group (12) via a mechanical coupling device (13), and the drive group (11) is fixed on the frame (14); Internal flow channels are provided at both ends of the driving group (11) and the refrigeration group (12) to establish a fluid path connection with the thermal cycle module (2).

9. A circulation method, characterized in that: The calorific value refrigeration system comprises any one of claims 1 to 8; and Providing heat to the driving group (11) through the heat transfer unit (21), so that the driving group (11) transforms from a martensite phase to an austenite phase and generates a driving force; The driving force generated by the driving group (11) is used to perform tension-torsion coupling loading on the refrigeration group (12) through a mechanical coupling device (13), so that the refrigeration group (12) is transformed from an austenite phase to a martensite phase, thereby achieving a refrigeration effect; and the piston (233) drives the fluid to flow from the low-temperature heat sink (2332) to the second normal-temperature heat sink (2331), thereby taking away the heat released by the refrigeration group (12); The cooling unit (22) is connected to the driving group (11), so that the driving group (11) dissipates heat and reversely transforms from the austenite phase to the martensite phase, and unloads the refrigeration group (12) through the mechanical coupling device (13); The unloading action of the driving group (11) causes the refrigeration group (12) to recover from the martensite phase to the austenite phase; and the piston (233) drives the fluid to flow from the second normal temperature heat sink (2331) to the low temperature heat sink (2332), absorbing heat and completing a refrigeration cycle.

10. The circulation method according to claim 9, characterized in that: When heating the drive group (11), the heat temperature provided by the heat transfer unit (21) is higher than the austenite termination temperature of the drive group (11); When the heat dissipation driving group (11) is performed, the temperature of the fluid provided by the first constant temperature heat sink (221) is lower than the martensite termination temperature of the driving group (11).

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