Active regenerator for a thermosyphon refrigeration and heat pump system and connection method

Abstract

The application discloses an active regenerator for a Stirling refrigeration and heat pump system and a connecting method, which comprises an upper press plate and a lower press plate with a sealing ring; the upper surface of the upper press plate is in contact with a loading head, and the lower surface is connected with the upper surface of an upper metal lining through dynamic sealing; the lower surface of the upper metal lining is in contact with the upper surface of a fluid channel; a shape memory alloy is arranged in the fluid channel; the lower surface of the fluid channel is in contact with the upper surface of a lower metal lining, the lower surface of the lower metal lining is connected with the upper surface of the lower press plate through dynamic sealing, and the lower surface of the lower press plate is fixed on a base; a heat transfer fluid flows into the fluid channel from the opening end of the fluid channel and exchanges heat with the shape memory alloy; the loading head can apply a single-axial compression force for driving the regenerator along the connecting line of the upper press plate and the lower press plate, which is perpendicular to the flow direction of the heat transfer fluid. The application can be connected to form a multi-stage regenerator, realizes high-efficiency heat exchange, and improves the system refrigeration power density.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of refrigeration and air conditioning, in particular to an active regenerator for the thermoelastic refrigeration and heat pump system and a connecting method. BACKGROUND

[0002] Global warming will lead to a series of problems such as glacier melting, sea level rise, frequent extreme weather and accelerated species extinction, so it is imperative to reduce greenhouse gas emissions. Greenhouse gas emissions from refrigeration and air conditioning equipment account for more than 7.8% of global annual greenhouse gas emissions, and 10%-30% of emissions from refrigeration and air conditioning equipment is due to the leakage of high global warming potential refrigerants. Despite the great efforts made by researchers, a completely ideal alternative refrigerant that meets zero ozone depletion potential, low global warming potential, non-flammable, non-toxic and high energy efficiency has not yet been found. Therefore, many researchers have turned their attention to non-vapor compression refrigeration technology. Thermoelastic refrigeration technology is considered to be the most promising alternative technology due to its high energy efficiency, zero global warming potential, etc.

[0003] Thermoelastic refrigeration technology utilizes the thermoelastic effect of shape memory alloy. When the axial stress applied to the shape memory alloy exceeds the phase transition stress, the shape memory alloy changes from austenite to martensite. Similarly, when the axial stress decreases below the phase transition stress, the shape memory alloy undergoes reverse phase transition and becomes martensite. The phase transition process is accompanied by the release and absorption of latent heat. Reverse phase transition will lead to an increase in the entropy of the shape memory alloy, absorbing heat from the environment and producing a refrigeration effect. After introducing the concept of active regenerator in the thermoelastic refrigeration and heat pump system, the system temperature difference can be increased to 19.9K, but the small power density is still a major obstacle for the commercialization of thermoelastic refrigeration technology. SUMMARY

[0004] The purpose of the present application is to solve the problems in the prior art, and to provide an active regenerator for the thermoelastic refrigeration and heat pump system and a connecting method, which realizes efficient heat exchange and improves the system refrigeration power density.

[0005] In order to achieve the above-mentioned purpose, the present application has the following technical solutions:

[0006] An active regenerator for a Stirling refrigeration and heat pump system, comprising an upper platen and a lower platen with a sealing ring; the upper surface of the upper platen is in contact with a loading head, and the lower surface is connected to the upper surface of an upper metal gasket by dynamic sealing; the lower surface of the upper metal gasket is in contact with the upper surface of a fluid channel; a shape memory alloy is installed in the fluid channel; the lower surface of the fluid channel is in contact with the upper surface of a lower metal gasket, and the lower surface of the lower metal gasket is connected to the upper surface of the lower platen by dynamic sealing; the lower surface of the lower platen is fixed on a base; a heat transfer fluid flows into the fluid channel from the first or second opening end of the fluid channel, exchanges heat with the shape memory alloy, and the loading head can apply a driving force to the regenerator along the connecting line of the upper platen and the lower platen, which is perpendicular to the flow direction of the heat transfer fluid, and the type of the force is uniaxial compression force.

[0007] As a preferred embodiment, the shape memory alloy is in an austenitic state at room temperature, generates strain under the action of the loading head, and transforms from austenite to martensite when the internal stress exceeds the phase transition stress, and releases latent heat to the heat transfer fluid; subsequently, the loading head unloads the pressure, and the shape memory alloy transforms from martensite to austenite when the internal stress of the shape memory alloy is less than the phase transition stress, and absorbs heat from the heat transfer fluid, generating a refrigeration effect.

[0008] As a preferred embodiment, the shape memory alloy is a tube bundle arranged in a cross arrangement, the driving stress is applied in the axial direction of the tube bundle, the heat transfer fluid flows along the outside of the tube, and fins perpendicular to the axial direction are arranged outside the tube bundle, and the fins are made of copper, aluminum or stainless steel.

[0009] As a preferred embodiment, the shape memory alloy is a foam metal, the porosity of the foam metal is 30% to 90%, and the foam metal has interconnected through holes inside, and the fluid flows from the through holes inside the foam metal.

[0010] As a preferred embodiment, the shape memory alloy is a micro-channel structure, the micro-channel structure has multiple parallel channels in the flow direction of the heat transfer fluid, the channel structure is circular, rectangular or hexagonal, and the hydraulic diameter of the channel is 0.1mm to 5mm.

[0011] As a preferred embodiment, the internal shape of the fluid channel matches the external contour of the shape memory alloy.

[0012] As a preferred embodiment, the Young's modulus of the material of the upper platen and the lower platen is not less than 110GPa, and the fluid channel is made of a material with a Young's modulus not higher than 70GPa and an elastic strain not less than 10% to match the strain of the shape memory alloy.

[0013] As a preferred embodiment, the upper surface of the upper metal gasket and the lower surface of the upper platen, and the lower surface of the lower metal gasket and the upper surface of the lower platen are dynamically sealed, and the periphery is fastened by bolt connection to provide an initial pre-tightening force when the regenerator is unloaded.

[0014] As a preference, the upper and lower pressing plates are connected by bolts on both sides to prevent mutual movement between the components.

[0015] A connecting method for active regenerators of a thermoacoustic refrigeration and heat pump system, comprising:

[0016] A plurality of active regenerators are stacked in the direction of the applied compression driving force to form a multi-stage regenerator, so that each stage of the regenerator is subjected to the same force when subjected to the compression driving force; the heat transfer fluid of the multi-stage regenerator is connected in series, parallel or series-parallel manner; the multi-stage regenerator is connected and fixed so that each stage of the regenerator is relatively stationary; in the fluid heat transfer stage, if the heat transfer fluid of the multi-stage regenerator is connected in series, the open ends between the adjacent two regenerators are connected in turn through U-shaped bends, and the flow directions of the heat transfer fluid of any two adjacent stages of the regenerator are opposite; if the heat transfer fluid of the multi-stage regenerator is connected in parallel, the heat transfer fluid is distributed by a distribution pipe and then enters the open ends on one side of each stage of the regenerator in parallel, the flow directions of the heat transfer fluid in all the regenerators are the same, then the heat transfer fluid flows out through the open ends on the other side of each stage of the regenerator, and is then collected by a collection pipe; if the heat transfer fluid of the multi-stage regenerator is connected in series-parallel manner, the series-parallel is a combination of series and parallel, at least one subset of the multi-stage regenerator adopts series connection, and at least one subset adopts parallel connection.

[0017] Compared with the prior art, the present application has at least the following beneficial effects:

[0018] The heat transfer fluid flows into the fluid channel from any open end on the fluid channel, exchanges heat with the shape memory alloy, and the loading head can apply a driving force to the regenerator along the connecting line direction of the upper and lower pressing plates, which is orthogonal to the flow direction of the heat transfer fluid. The shape memory alloy in the active regenerator of the present application is driven by compression load, and compared with the regenerator driven by tensile load, the fatigue life of the shape memory alloy is increased. The shape memory alloy in the active regenerator of the present application is assembled in the fluid channel, the heat exchange area of the shape memory alloy is large, the heat exchange capacity is improved, the working frequency range of the refrigeration system is expanded, and there is great potential in improving the refrigeration power density. The fluid channel is equivalent to a flow distributor, which is placed around the shape memory alloy, increases the contact between the heat transfer fluid and the shape memory alloy, and thus improves the heat exchange performance.

[0019] The application is a connecting method of active regenerator for the Stirling refrigeration and heat pump system, which can stack multiple regenerators in the direction of applying compression driving force to form a multi-stage regenerator, and the connecting method is simple. The stress of each stage of regenerator is completely the same when it is subjected to the compression driving force, and the stage number is not more than 50, and the heat transfer fluid of the multi-stage regenerator can be connected by series connection, parallel connection or series-parallel connection. The application not only realizes the high efficient heat exchange between the active regenerator and the heat transfer fluid, improves the refrigeration power density of the Stirling refrigeration and heat pump system, but also improves the refrigeration temperature difference of the system by using the multi-stage regenerator formed by connection. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the application, and other related drawings can also be obtained by those skilled in the art without creating labor.

[0021] FIG. 1A The schematic diagram of the assembly of each component of the regenerator in the embodiment of the application;

[0022] FIG. 1B The schematic diagram of the assembly of each component of the regenerator in the embodiment of the application;

[0023] FIG. 2A The structure diagram of the fluid channel of the hollow regenerator and the fluid channel assembled with the tube bundle structure shape memory alloy:

[0024] (a) the perspective structure diagram; (b) the A-A section structure diagram; (c) the B-B section structure diagram;

[0025] FIG. 2B The structure diagram of the fluid channel of the hollow regenerator and the fluid channel assembled with the foam structure shape memory alloy:

[0026] (a) the perspective structure diagram; (b) the A-A section structure diagram; (c) the B-B section structure diagram;

[0027] FIG. 2C The structure diagram of the fluid channel of the hollow regenerator and the fluid channel assembled with the micro-channel structure shape memory alloy:

[0028] (a) the perspective structure diagram; (b) the A-A section structure diagram; (c) the B-B section structure diagram;

[0029] FIG. 3A The series connection schematic diagram of the three-stage regenerator;

[0030] FIG. 3B The parallel connection schematic diagram of the three-stage regenerator;

[0031] FIG. 3C Schematic diagram of series and parallel connection of three-stage regenerators. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, those skilled in the art can obtain other embodiments without creative effort.

[0033] like FIG. 1A and FIG. 1B As shown, the active regenerator for elasto-thermal refrigeration and heat pump systems of this invention includes an upper pressure plate 102 and a lower pressure plate 106 with sealing rings 107, and a fluid channel 104 equipped with shape memory alloy 111. The upper pressure plate 102 and the lower pressure plate 106 are respectively connected to the upper surface of the upper metal liner 103 and the lower surface of the lower metal liner 105. The lower surface of the upper metal liner 103 and the upper surface of the lower metal liner 105 are connected to the fluid channel. The lower surface of the lower pressure plate 106 is fixed to the base. The heat transfer fluid flows into the fluid channel 104 from the first opening end 110-1 or the second opening end 110-2, and exchanges heat with the shape memory alloy 111. A force driving the regenerator can be applied along the connection line of the upper pressure plate 102 and the lower pressure plate 106 through the loading head 101. The force is orthogonal to the flow direction of the heat transfer fluid and is a uniaxial compressive force.

[0034] When the loading head 101 is loaded, the stress is transmitted to the fluid channel 104 and the shape memory alloy 111 therein through the upper pressure plate 102. The shape memory alloy 111 generates strain. At the same time, the fluid channel 104, which is made of a flexible material with a Young's modulus of not more than 70 GPa and an elastic strain of not less than 10%, also experiences the same strain. All the components of the entire regenerator remain in close contact and do not move relative to each other.

[0035] When the loading head 101 is unloaded, the shape memory alloy 111 undergoes reverse martensitic phase transformation (from martensite to austenite) and absorbs heat, the upper platen 102 and the lower platen 106 are connected to the upper surface of the upper metal gasket 103 and the lower surface of the lower metal gasket 105 respectively through the sealing ring 107, and the pre-tightening force is provided by the fastening parts 113 such as bolts, nuts, etc. to avoid leakage of the heat transfer fluid from the gaps between the upper metal gasket 103, the lower metal gasket 105 and the upper platen 102, the lower platen 106. The lower surface of the upper metal gasket 103 and the upper surface of the lower metal gasket 105 are adhered to the fluid channel by glue. The fastening parts 112 such as studs, bolts, etc. are screwed into the threaded holes 109 on both sides of the upper platen 102 and the lower platen 106, so that all parts of the entire regenerator are in close contact when not under pressure, avoiding leakage of the heat transfer fluid and mutual movement between the parts.

[0036] In the fluid flow stage, the heat transfer fluid flows to the heat source or the heat sink through the first open end 110-1 or the second open end 110-2 of the fluid channel 104. If the temperature gradient of the shape memory alloy 111 from the first open end 110-1 to the second open end 110-2 is high temperature to low temperature, after the loading head 101 is loaded, the fluid flows from the second open end 110-2 to the first open end 110-1 of the fluid channel 104 to absorb heat, and after the loading head 101 is unloaded, the fluid flows from the first open end 110-1 to the second open end 110-2 of the fluid channel 104 and releases heat. If the temperature gradient of the shape memory alloy 111 from the first open end 110-1 to the second open end 110-2 is low temperature to high temperature, after the loading head is loaded, the fluid flows from the first open end 110-1 to the second open end 110-2 of the fluid channel 104 to absorb heat, and after the loading head is unloaded, the fluid flows from the second open end 110-2 to the first open end 110-1 of the fluid channel 104 and releases heat.

[0037] The shape memory alloy material can be a tube bundle, a foam, a microchannel, etc. The internal shape of the fluid channel 104 should match the structure of the shape memory alloy 111, FIGS. 2A-2C Figures (a), (b), (c) respectively show the hollow fluid channel 104 equipped with different structures of the shape memory alloy 111, and the cross-sectional view of the fluid channel 104 after the shape memory alloy 111 is assembled. As shown in FIG. 2A As shown in Figures (a), (b), (c), for the tube bundle structure of the shape memory alloy 111-1, the fluid channel makes the size of the space around all the circular tubes similar, which not only uniformly distributes the fluid flow around each circular tube, but also increases the contact between the fluid and the circular tube, enhances heat exchange, and further the tube bundle can have fins perpendicular to the axial direction, which are made of copper, aluminum or stainless steel materials, for strengthening heat transfer. As shown in FIG. 2BAs shown in Figs. (a), (b), (c), for the foam structure shape memory alloy 111-2, the shape of the fluid channel matches the shape of the shape memory alloy material, so that all the fluid flows through the pores of the foam structure shape memory alloy, and exchanges heat with the shape memory alloy material sufficiently. As shown in Figs. (a), (b), (c), the micro-channel structure shape memory alloy 111-3 runs through the entire fluid channel, which provides support for the shape memory alloy 111-3. FIG. 2C As shown in Figs. (a), (b), (c), the micro-channel structure shape memory alloy 111-3 runs through the entire fluid channel, which provides support for the shape memory alloy 111-3.

[0038] Further, multiple regenerators of the embodiments of the present application can be stacked in the direction of the applied compression driving force to form a multi-stage regenerator, each stage of the regenerator is subjected to the same force when subjected to the compression driving force, and the number of stages is not more than 50 stages. The heat transfer fluid of the multi-stage regenerator can be connected in series, in parallel, or in series-parallel. The fastening part 112 is screwed into the two threaded holes 109 of the upper and lower pressure plates 102 and 106, so that the relative positions of the stages of the regenerator are static.

[0039] FIGS. 3A-3C A specific embodiment of the series connection, parallel connection, and series-parallel connection of the multi-stage regenerator is described, which is the connection of a three-stage regenerator. The specific embodiments described herein are only used to explain the scheme of the present application and do not limit the present application.

[0040] FIG. 3AThe connection mode of the three-stage regenerator is in series. The loading head 101 compresses the upper pressure plate 102 of the first-stage regenerator. The upper pressure plate 102 transmits the stress to the fluid channel 104-1 and the shape memory alloy 111 in the first-stage regenerator. The fluid channel 104-1 and the shape memory alloy 111 in the first-stage regenerator transmit the stress to the lower pressure plate 114 of the first-stage regenerator and the upper pressure plate 114 of the second-stage regenerator. The upper pressure plate 114 transmits the stress to the fluid channel 104-2 and the shape memory alloy 111 in the second-stage regenerator. Then the fluid channel 104-2 and the shape memory alloy 111 in the second-stage regenerator transmit the stress to the lower pressure plate 115 of the second-stage regenerator and the upper pressure plate 115 of the third-stage regenerator. Finally, the upper pressure plate 115 transmits the stress to the shape memory alloy 111 of the third-stage regenerator. The shape memory alloys 111 in the three-stage regenerator are subjected to the same stress. When the internal stress exceeds the phase transition stress, the martensite phase transition occurs, the austenite changes into martensite, and heat is released. The temperature of the three-stage regenerator rises simultaneously. The valve in the fluid exchange network is opened. The heat transfer fluid flows into the first opening end 110-1 of the fluid channel 104-1 of the first-stage regenerator, flows through the fluid channel 104-1 of the first-stage regenerator, exchanges heat with the shape memory alloy 111 in the first-stage regenerator, then flows out from the second opening end 110-2 of the fluid channel 104-1, enters the fourth opening end 110-4 of the fluid channel 104-2 of the second-stage regenerator through the connecting pipe 116, absorbs the heat of the shape memory alloy 111 in the second-stage regenerator in the fluid channel 104-2, and finally flows out from the third opening end 110-3 of the channel 104-2, flows into the fifth opening end 110-5 of the fluid channel 104-3 of the third-stage regenerator through the connecting pipe 117, and absorbs the heat of the shape memory alloy 111 in the third-stage regenerator. The heat transfer fluid flows out from the sixth opening end 110-6 of the fluid channel 104-3 of the third-stage regenerator. The series connection establishes the opposite temperature gradient between the first-stage regenerator and the second-stage regenerator, and the same temperature gradient between the first-stage regenerator and the third-stage regenerator. According to the above flow mode, the heat transfer fluid flows into the first opening end 110-1 of the fluid channel 104-1 of the first-stage regenerator and finally flows out from the sixth opening end 110-6 of the fluid channel 104-3 of the third-stage regenerator. The temperature gradient of the fluid channel 104-1 and the shape memory alloy 111 of the first-stage regenerator is established from the first opening end 110-1 to the second opening end 110-2, from low temperature to high temperature. The temperature gradient of the fluid channel 104-2 and the shape memory alloy 111 of the second-stage regenerator is established from the third opening end 110-3 to the fourth opening end 110-4, from high temperature to low temperature. The temperature gradient of the fluid channel 104-3 and the shape memory alloy 111 of the second-stage regenerator is established from the fifth opening end 110-5 to the sixth opening end 110-6, from low temperature to high temperature.Of course, fluid can also flow into the second stage regenerator fluid channel 104-3 from the sixth open end 110-6 and finally flow out from the first stage regenerator fluid channel 104-1 from the first open end 110-1, which will establish a temperature gradient in the third stage regenerator corresponding to the flow direction, but once the temperature gradient is established in the regenerator, the fluid flow direction cannot be changed, during the fluid flow process after loading, fluid can only flow from the low temperature section of the regenerator to the high temperature section, and during the fluid flow process after unloading, fluid can only flow from the high temperature section of the regenerator to the low temperature section. After the loading head 101 is unloaded, the shape memory alloy 111 in the third stage regenerator all undergoes reverse phase change from martensite to austenite, the temperature of the shape memory alloy 111 and the fluid channel 104 as a whole decreases, and the heat transfer fluid flows from the high temperature section of the regenerator to the low temperature section of the regenerator, if the fluid flows from the first open end 110-1 of the first stage regenerator fluid channel 104-1 to the sixth open end 110-6 of the third stage regenerator fluid channel 104-3 after loading, then after unloading, the fluid flows from the sixth open end 110-6 of the third stage regenerator fluid channel 104-3 to the first open end 110-1 of the first stage regenerator fluid channel 104-1, and vice versa.

[0041] FIG. 3BThe parallel connection mode of the three-stage regenerator is the same as the loading process and the series connection mode, loaded by the loading head 101, the stress is transmitted to the shape memory alloy 111 in the three-stage regenerator, and the shape memory alloy 111 in the three-stage regenerator all undergoes martensitic transformation, and the temperature rises. In the parallel three-stage regenerator, the fluid is distributed by the flow divider, and then flows into the first-stage regenerator fluid channel 104-1 from the first opening end 110-1, the second-stage regenerator fluid channel 104-2 from the third opening end 110-3, and the third-stage regenerator fluid channel 104-5 from the fifth opening end 110-5, absorbs the heat of the first-stage regenerator fluid channel 104-1 and its shape memory alloy 111, the second-stage regenerator fluid channel 104-2 and its shape memory alloy 111, and the third-stage regenerator fluid channel 104-3 and its shape memory alloy 111, and then flows out from the second opening end 110-2 of the first-stage regenerator fluid channel 104-1, the fourth opening 110-4 of the second-stage regenerator fluid channel 104-2, and the sixth opening end 110-6 of the third-stage regenerator fluid channel 104-3, respectively. Such a flow mode makes the three-stage regenerator establish a temperature gradient in the same direction, from the first opening end 110-1 to the second opening end 110-2 of the first-stage regenerator, a temperature gradient from high temperature to low temperature is established, from the third opening end 110-3 to the fourth opening end 110-4 of the second-stage regenerator, a temperature gradient from high temperature to low temperature is established, from the fifth opening end 110-5 to the sixth opening end 110-6 of the third-stage regenerator. Of course, the fluid can also flow into the second opening end 110-2 of the first-stage regenerator fluid channel 104-1, the fourth opening end 110-4 of the second-stage regenerator fluid channel 104-2, and the sixth opening end 110-6 of the third-stage regenerator fluid channel 104-3 at the same time, and then flow out from the first opening end 110-1 of the first-stage regenerator fluid channel 104-1, the third opening end 110-3 of the second-stage regenerator fluid channel 104-2, and the fifth opening end 110-5 of the third-stage regenerator fluid channel 104-3, respectively, which will make the three-stage regenerator establish a temperature gradient corresponding to the flow direction, but once the temperature gradient is established in the regenerator, the fluid flow direction cannot be changed. In the fluid flow process after loading, the fluid can only flow from the low temperature section of the regenerator to the high temperature section, and in the fluid flow process after unloading, the fluid can only flow from the high temperature section of the regenerator to the low temperature section.After the loading head is unloaded, the temperature of the shape memory alloy 111 and the fluid channel 104 as a whole decreases, and the heat transfer fluid flows from the high-temperature section of the regenerator to the low-temperature section of the regenerator. If the fluid after loading flows from the first open end 110-1 of the first-stage regenerator, the third open end 110-3 of the second-stage regenerator, and the fifth open end 110-5 of the third-stage regenerator to the second open end 110-2 of the first-stage regenerator, the fourth open end 110-4 of the second-stage regenerator, and the sixth open end 110-6 of the third-stage regenerator, respectively, then after unloading, the fluid flows from the second open end 110-2 of the first-stage regenerator, the fourth open end 110-4 of the second-stage regenerator, and the sixth open end 110-6 of the third-stage regenerator to the first open end 110-1 of the first-stage regenerator, the third open end 110-3 of the second-stage regenerator, and the fifth open end 110-5 of the third-stage regenerator, respectively, and vice versa.

[0042] FIG. 3CThe connection mode of the three-stage regenerator is series-parallel connection, which is the same as series connection and parallel connection. The stress is transmitted from the loading head 101 to the shape memory alloy 111 in the three-stage regenerator. When the internal stress of the shape memory alloy 111 exceeds the phase transition stress, the martensitic phase transition occurs, and the temperature rises. In the series-parallel three-stage regenerator, the fluid flows into the first-stage regenerator fluid channel 104-1 from the first open end 110-1 and the third-stage regenerator fluid channel 104-5 from the fifth open end 110-5 after flow distribution. The fluid flowing into the first-stage regenerator fluid channel 104-1 from the first open end 110-1 absorbs the heat of the shape memory alloy 111 in the first-stage regenerator, flows out from the second open end 110-2, flows into the fourth open end 110-4 of the second-stage regenerator fluid channel 104-2 through the connecting pipe 118, absorbs the heat of the shape memory alloy 111 in the second-stage regenerator, and finally flows out from the third open end 110-3 of the second-stage regenerator fluid channel 104-2. The fluid flowing into the third-stage regenerator fluid channel 104-3 from the fifth open end 110-5 absorbs the heat of the shape memory alloy 111 in the third-stage regenerator, and then flows out from the sixth open end 110-6 of the third-stage regenerator fluid channel 104-3. Such a flow mode establishes opposite temperature gradients in the first-stage regenerator and the second-stage regenerator, and establishes the same temperature gradient in the first-stage regenerator and the third-stage regenerator. From the first open end 110-1 to the second open end 110-2 of the first-stage regenerator, a temperature gradient from low temperature to high temperature is established. From the third open end 110-3 to the fourth open end 110-4 of the second-stage regenerator, a temperature gradient from high temperature to low temperature is established. From the fifth open end 110-5 to the sixth open end 110-6 of the third-stage regenerator, a temperature gradient from low temperature to high temperature is also established. Of course, the fluid can also flow into the third open end 110-3 of the second-stage regenerator fluid channel 104-2 and the sixth open end 110-6 of the third-stage regenerator fluid channel 104-3 at the same time, and then flow out from the first open end 110-1 of the first-stage regenerator fluid channel 104-1 and the fifth open end 110-5 of the third-stage regenerator fluid channel 104-3, respectively. This will establish a temperature gradient corresponding to the flow direction in the three-stage regenerator, but once the temperature gradient is established in the regenerator, the fluid flow direction cannot be changed. During the fluid flow process after loading, the fluid can only flow from the low-temperature section to the high-temperature section of the regenerator, and during the fluid flow process after unloading, the fluid can only flow from the high-temperature section to the low-temperature section of the regenerator.After the loading head 101 is unloaded, the temperature of the shape memory alloy 111 and the fluid channel 104 as a whole decreases, and the heat transfer fluid flows from the high-temperature section of the regenerator to the low-temperature section of the regenerator. If the fluid after loading flows from the first opening end 110-1 of the first-stage regenerator and the fifth opening end 110-5 of the third-stage regenerator to the third opening end 110-3 of the second-stage regenerator and the sixth opening end 110-6 of the third-stage regenerator, respectively, then after unloading, the fluid flows from the third opening end 110-3 of the second-stage regenerator and the sixth opening end 110-6 of the third-stage regenerator to the first opening end 110-1 of the first-stage regenerator and the fifth opening end 110-5 of the third-stage regenerator, respectively. Conversely, the same applies.

[0043] The design elements of the active regenerator of the present application and the series, parallel, and series-parallel connection modes of the multi-stage regenerator are described above. According to different requirements, the three basic connection modes can be combined together to connect multiple regenerators into a three-stage, four-stage, five-stage, or multi-stage regenerator, to meet the temperature and refrigeration power requirements.

[0044] The above-described embodiments are merely used to illustrate the technical solutions of the present application, but not to limit the present application; even though the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can be modified, or some technical features can be replaced equivalently; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

Claims

1. An active regenerator for a Stirling refrigeration and heat pump system, characterized by: The device comprises an upper platen (102) and a lower platen (106) with a sealing ring (107); the upper surface of the upper platen (102) is in contact with the loading head (101), and the lower surface is connected with the upper surface of the upper metal gasket (103) through dynamic sealing; the lower surface of the upper metal gasket (103) is in contact with the upper surface of the fluid channel (104); the fluid channel (104) is equipped with a shape memory alloy (111); the lower surface of the fluid channel (104) is in contact with the upper surface of the lower metal gasket (105), and the lower surface of the lower metal gasket (105) is connected with the upper surface of the lower platen (106) through dynamic sealing; the lower surface of the lower platen (106) is fixed on the base; the heat transfer fluid flows into the fluid channel (104) from the first opening end (110-1) or the second opening end (110-2) of the fluid channel (104), exchanges heat with the shape memory alloy (111), and the loading head (101) can apply a driving force to the regenerator along the connecting line direction of the upper platen (102) and the lower platen (106), which is perpendicular to the flow direction of the heat transfer fluid, and the type of the force is uniaxial compression force; the upper surface of the upper metal gasket (103) and the lower surface of the upper platen (102), and the lower surface of the lower metal gasket (105) and the upper surface of the lower platen (106) are dynamically sealed, and the periphery is fastened through bolt connection to provide initial pre-tightening force when the regenerator is unloaded; the two sides of the upper platen (102) and the lower platen (106) are connected through bolt connection to prevent mutual movement between the components.

2. The active regenerator for the Caloric cooling and heat pumping system according to claim 1, characterized in that: The shape memory alloy (111) is in austenitic state at normal temperature, generates strain under the action of the loading head (101), and transforms from austenite to martensite when the internal stress exceeds the phase transition stress, and releases latent heat to the heat transfer fluid; subsequently, the loading head (101) unloads pressure, and the shape memory alloy (111) transforms from martensite to austenite when the internal stress of the shape memory alloy (111) is less than the phase transition stress, and absorbs heat from the heat transfer fluid to produce a refrigeration effect.

3. The active regenerator for the Caloric cooling and heat pumping system of claim 1, wherein: The shape memory alloy (111) is arranged in a tube bundle (111-1) in a forked manner, the driving stress is applied along the axial direction of the tube bundle, the heat transfer fluid flows along the outside of the tube, and fins perpendicular to the axial direction of the tube are arranged on the outside of the tube bundle (111-1), and the fins are made of copper, aluminum or stainless steel.

4. The active regenerator for the Caloric cooling and heat pumping system of claim 1, wherein: The shape memory alloy (111) is a foam metal (111-2), the porosity of the foam metal (111-2) is 30% to 90%, and the foam metal (111-2) has interconnected through holes inside.

5. The active regenerator for the Caloric cooling and heat pumping system of claim 1, wherein: The shape memory alloy (111) is a micro-channel structure (111-3), the micro-channel structure (111-3) has a plurality of parallel channels along the flow direction of the heat transfer fluid, the channel structure is circular, rectangular or hexagonal, and the hydraulic diameter of the channel is 0.1mm to 5mm.

6. The active regenerator for the Caloric cooling and heat pumping system of claim 1, wherein: The internal shape of the fluid channel (104) matches the external contour of the shape memory alloy (111).

7. The active regenerator for the Caloric cooling and heat pumping system of claim 1, wherein: The Young's modulus of the upper and lower press plates (102, 106) is not less than 110 GPa, and the fluid channel (104) is made of a material with a Young's modulus not higher than 70 GPa and an elastic strain not less than 10% to match the strain of the shape memory alloy (111).

8. A method of connecting an active regenerator for a Stirling refrigeration and heat pump system as claimed in any one of claims 1 to 7, characterised in that, The application relates to a heat exchanger. A plurality of active regenerators are stacked in the direction of the applied compression driving force to form a multi-stage regenerator, so that each stage of the regenerator is subjected to the same force when subjected to the compression driving force; the heat transfer fluid of the multi-stage regenerator is connected in series, in parallel or in series-parallel mode; the multi-stage regenerator is connected and fixed, so that each stage of the regenerator is relatively static; in the fluid heat transfer stage, if the heat transfer fluid of the multi-stage regenerator is connected in series mode, the opening ends between two adjacent regenerators are connected in sequence through U-shaped elbows, and the flow directions of the heat transfer fluid of any two adjacent stages of the regenerator are opposite; if the heat transfer fluid of the multi-stage regenerator is connected in parallel mode, the heat transfer fluid is distributed in flow through a distribution pipe, then enters the opening ends on one side of each stage of the regenerator in parallel, the flow directions of the heat transfer fluid in all the regenerators are the same, then the heat transfer fluid flows out through the opening ends on the other side of each stage of the regenerator, and is converged through a collecting pipe; if the heat transfer fluid of the multi-stage regenerator is connected in series-parallel mode, the series-parallel mode is a combination of series connection and parallel connection, at least one subset of the multi-stage regenerator adopts series connection, and at least one subset adopts parallel connection.

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