阅读说明：本技术 一种热驱动型弹热热泵循环方法及系统 (Heat-driven elastic heat pump circulation method and system ) 是由 钱苏昕 许世杰 于 2020-03-27 设计创作，主要内容包括：一种热驱动型弹热热泵循环方法及系统,系统包括中温驱动组记忆合金、高温热泵组记忆合金以及中温热源、高温热汇、常温热汇三个热源；高温热泵组记忆合金的奥氏体终止温度T<Sub>af2</Sub>低于中温热源的温度T<Sub>g</Sub>,但T<Sub>af2</Sub>高于中温驱动组记忆合金的奥氏体终止温度T<Sub>af1</Sub>,中温驱动组记忆合金的马氏体终止温度T<Sub>mf1</Sub>高于常温热汇的温度T<Sub>c</Sub>；中温驱动组记忆合金与高温热泵组记忆合金之间通过机械耦合部件相连。中温驱动组形状记忆合金从一个温度为T<Sub>g</Sub>的低品位中温热源吸热,向温度为T<Sub>c</Sub>的常温热汇排热,为热泵组形状记忆合金提供驱动力,使其将温度为T<Sub>g</Sub>的中温热源的热量释放至温度为T<Sub>h</Sub>的高温热汇,实现低品位热能品位的提升。(A heat-driven elastic heat pump circulation method and system, the system includes medium temperature driving group memory alloy, high temperature heat pump group memory alloy and medium temperature heat source, high temperature heat sink, three heat sources of normal temperature heat sink; austenite finish temperature T of high temperature heat pump set memory alloy af2 Lower than temperature T of medium-temperature heat source g But T is af2 The austenite termination temperature T is higher than that of the medium-temperature drive group memory alloy af1 Martensite finish temperature T of medium temperature drive group memory alloy mf1 Temperature T higher than normal temperature heat sink c (ii) a The medium-temperature driving group memory alloy is connected with the high-temperature heat pump group memory alloy through a mechanical coupling part. The medium temperature driving group shape memory alloy has a temperature T g The low-grade medium-temperature heat source absorbs heat to the temperature of T c The normal temperature heat sink discharges heat, and provides driving force for the shape memory alloy of the heat pump set to ensure that the temperature is T g The heat of the medium-temperature heat source is released to the temperature T h The grade of low-grade heat energy is improved by the high-temperature heat sink.)

1. A heat-driven elastic heat pump circulation method is characterized by comprising the following steps:

the first process is as follows: the medium temperature driving set memory alloy (106) is formed by the temperature T_gThe medium-temperature heat source (102) is used for heating, and the driving force required by the loading process is provided for the high-temperature heat pump set memory alloy (107) through the mechanical coupling component (108);

the high temperature heat pump group memory alloy (107) is added by the medium temperature driving group memory alloy (106)The phase-loaded phase is transformed into martensite, and the temperature of the phase transformation process is raised to the temperature T of the high-temperature heat sink (101)_hThe above;

the second process: medium temperature drive set memory alloy (106) hold T_gThe temperature outputs driving force, and simultaneously the heat of the memory alloy (107) of the high-temperature heat pump set is discharged into a high-temperature heat sink (101), so that the output of high-grade heat energy is realized;

the third process: the medium temperature drive set memory alloy (106) is heated to T_cCooling the normal temperature heat sink (103), changing from austenite to martensite, unloading the high temperature heat pump set memory alloy (107) through the mechanical coupling component (108), wherein the temperature of the high temperature heat pump set memory alloy (107) is reduced to be lower than the temperature T of the medium temperature heat source in the unloading phase change process_g；

A fourth process: the high temperature heat pump set memory alloy (107) is heated to T_gThe medium temperature heat source (102) of (2).

2. The thermal drive type elasto-thermal heat pump cycle method according to claim 1, characterized in that:

austenite finish temperature T of the high temperature heat pump set memory alloy (107)_af2Lower than the temperature T of the medium temperature heat source (102)_gBut T is_af2Above the austenite finish temperature T of the medium temperature drive set memory alloy (106)_af1Martensite finish temperature T of medium temperature drive set memory alloy (106)_mf1The temperature T is higher than the normal temperature heat sink (103)_c。

3. A heat pump system implementing the thermal drive type elastic heat pump cycle method according to claim 1, characterized in that: the device comprises three heat sources, namely a medium-temperature driving group memory alloy (106), a high-temperature heat pump group memory alloy (107) and a medium-temperature heat source (102), a high-temperature heat sink (101) and a normal-temperature heat sink (103); austenite finish temperature T of the high temperature heat pump set memory alloy (107)_af2Lower than the temperature T of the medium temperature heat source (102)_gBut T is_af2The austenite termination temperature T is higher than that of the medium-temperature drive group memory alloy_af1Martensite finish temperature T of medium temperature drive group memory alloy_mf1The temperature T is higher than the normal temperature heat sink (103)_c(ii) a Medium temperature driving setThe memory alloy (106) and the high-temperature heat pump group memory alloy (107) are connected through a mechanical coupling part (108), and the medium-temperature driving group memory alloy (106) and the high-temperature heat pump group memory alloy (107) are respectively connected with three heat sources through pipelines; one end of the medium-temperature driving group memory alloy (106) is fixedly connected with the mechanical coupling part (108), and the other end of the medium-temperature driving group memory alloy is fixedly connected with the rack (113); one end of the high-temperature heat pump group memory alloy (107) is fixedly connected with the mechanical coupling component (108), the other end of the high-temperature heat pump group memory alloy is fixedly connected with the rack (113), and the total length of the medium-temperature drive group memory alloy (106) and the high-temperature heat pump group memory alloy (107) is restricted by the rack (113).

4. The heat pump system of claim 3, wherein:

a second three-way valve (105-2) is arranged on a pipeline between the memory alloy (106) of the intermediate temperature driving group and the normal temperature heat sink (103), and the second three-way valve (105-2) is connected with the intermediate temperature heat source (102) through a pipeline; the medium-temperature driving group memory alloy (106) is also respectively connected with the normal-temperature heat sink (103) and the medium-temperature heat source (102) sequentially through a second circulating pump (104-2) and a third three-way valve (105-3);

a fourth three-way valve (105-4) is arranged on a pipeline between the memory alloy (107) of the high-temperature heat pump group and the high-temperature heat sink (101), and the fourth three-way valve (105-4) is connected with the medium-temperature heat source (102) through a pipeline; the high-temperature heat pump group memory alloy (107) is also respectively connected with the high-temperature heat sink (101) and the medium-temperature heat source (102) through a first circulating pump (104-1) and a fifth three-way valve (105-5) in sequence.

5. The heat pump system of claim 3, wherein: a second three-way valve (105-2) is arranged on a pipeline between the memory alloy (106) of the intermediate temperature driving group and the normal temperature heat sink (103), and the second three-way valve (105-2) is connected with the intermediate temperature heat source (102) through a pipeline; the medium-temperature driving group memory alloy (106) is also respectively connected with the normal-temperature heat sink (103) and the medium-temperature heat source (102) sequentially through a second circulating pump (104-2) and a third three-way valve (105-3); the method comprises the following steps that a high-temperature heat pump set memory alloy (107) runs an active regenerative heat pump cycle, a hot end is connected with a high-temperature heat sink (101), a cold end of the high-temperature heat pump set memory alloy is connected with a medium-temperature heat source (102) through a four-way valve (110) and a first circulating pump (104-1), the four-way valve (110) has two communication modes, and when the high-temperature heat pump set memory alloy (107) is subjected to phase change and temperature rise and needs heat removal, a heat exchange fluid enters the high-temperature heat pump set memory alloy (107) from the medium-temperature heat source (102) through the four-way valve (110), the first circulating pump (104; when the high-temperature heat pump set memory alloy (107) needs to absorb heat after phase change and temperature reduction, the heat exchange fluid is absorbed into the high-temperature heat pump set memory alloy (107) from the high-temperature heat sink (101) and enters the medium-temperature heat source (102) through the four-way valve (110), the first circulating pump (104-1) and the four-way valve (110).

6. The heat pump system of claim 3, wherein: a second three-way valve (105-2) is arranged on a pipeline between the memory alloy (106) of the intermediate temperature driving group and the normal temperature heat sink (103), and the second three-way valve (105-2) is connected with the intermediate temperature heat source (102) through a pipeline; the medium-temperature driving group memory alloy (106) is also respectively connected with the normal-temperature heat sink (103) and the medium-temperature heat source (102) sequentially through a second circulating pump (104-2) and a third three-way valve (105-3); the memory alloy (107) of the high-temperature heat pump set operates an active regenerative heat pump cycle, the hot end of the high-temperature heat pump set is connected with a high-temperature heat sink (101), and the cold end of the high-temperature heat pump set is respectively connected with a medium-temperature heat source (102) or a medium-temperature drive set memory alloy (106) through a four-way valve (110), a first circulating pump (104-1) and a first three-way valve (105-1);

the four-way valve (110) has two communication modes, when the high-temperature heat pump set memory alloy (107) needs heat extraction after phase change and temperature rise, the heat exchange fluid enters the high-temperature heat pump set memory alloy (107) from the medium-temperature heat source (102) through the medium-temperature driving set memory alloy (106), the first three-way valve (105-1), the four-way valve (110), the first circulating pump (104-1) and the four-way valve (110) in sequence, absorbs heat and then enters the high-temperature heat sink (101); when the high-temperature heat pump set memory alloy (107) needs to absorb heat after phase change and temperature reduction, heat exchange fluid is sucked into the high-temperature heat pump set memory alloy (107) from the high-temperature heat sink (101) and enters the medium-temperature heat source (102) through the four-way valve (110), the first circulating pump (104-1), the four-way valve (110) and the first three-way valve (105-1) in sequence.

7. The heat pump system of claim 6, wherein: the medium-temperature driving group memory alloy (106) is connected with the medium-temperature heat source (102) through a first one-way valve (109-1), and a second one-way valve (109-2) is arranged between the medium-temperature driving group memory alloy (106) and a second three-way valve (105-2); two modes of communication heat exchange between the medium-temperature driving group memory alloy (106) and the medium-temperature heat source (102) and communication heat exchange between the medium-temperature driving group memory alloy (106) and the normal-temperature heat sink (103) are realized through the second three-way valve (105-2), the third three-way valve (105-3), the second one-way valve (109-2) and the second circulating pump (104-2).

8. The heat pump system of claim 3, wherein:

the high-temperature heat pump group memory alloy (107) realizes the phase transformation from austenite to martensite by compression stress, tensile stress, torsional stress or the combination of the driving loading stress forms, and can be transformed from austenite to martensite after the driving loading stress is removed, thereby obtaining the refrigerating capacity; the driving loading stress of the high-temperature heat pump group memory alloy (107) is provided by the medium-temperature driving group memory alloy (106) in the process of heating and transforming martensite into austenite, and the medium-temperature driving group memory alloy (106) provides compression stress, tensile stress or torsional stress when being heated by utilizing the shape memory effect.

9. The heat pump system of claim 3, wherein: the mechanical coupling component (108) is a component for transmitting linear tension, linear compression and torsional torque, or a device for converting the linear tension, linear compression and torsional torque of the medium-temperature driving group memory alloy (106) into any one of the driving forces required by the high-temperature heat pump group memory alloy (107).

10. The heat pump system of claim 3, wherein: the medium temperature heat source (102) has the temperature T_gThe solid or the closed medium temperature fluid or any one of a plate heat exchanger, a plate-fin heat exchanger, a tube-fin heat exchanger, a micro-channel heat exchanger and a shell-and-tube heat exchanger which are contacted with the medium temperature fluid; the heat source of the medium-temperature heat source (102) comprises solar energy, terrestrial heat, waste heat of an automobile engine or exhaust, industrial waste heat and electronic product wasteAnd (4) heating.

Technical Field

The invention belongs to the field of heat energy treatment, and particularly relates to a heat-driven elastic heat pump circulation method and system.

Background

Energy shortage and environmental pollution become a considerable problem in the development process of China. Energy consumption in the industrial field of China accounts for about 70% of the total energy consumption of China, and except for the factors of immature production process, unreasonable capacity and structure, extensive development and the like, the important reason that the energy consumption is higher is that the utilization rate of industrial waste heat is low and the energy is not fully and reasonably utilized. According to investigation, the total waste heat resources of various industries in China account for 17% -67% of the total fuel consumption, wherein the recoverable waste heat accounts for 60% of the total waste heat. The recovery of industrial waste heat is a very significant and promising field. The temperature of the industrial waste heat is generally lower than 100 ℃, and besides the grade is reduced for supplying heat for civil use, an important way for recycling is to carry out synergistic temperature rise on the low-grade industrial waste heat. The second-class absorption heat pump is a core technology for realizing the low-grade heat efficiency improvement, and can convert low-grade waste heat into high-grade heat energy for reutilization, so that the purposes of saving energy and eliminating heat pollution are achieved.

The second type absorption heat pump is driven by a medium-temperature heat source, and the other part of medium-temperature heat is raised to a higher temperature by virtue of the potential difference between the medium-temperature heat source and a low-temperature heat source, so that the energy grade is raised. The coefficient of performance is generally less than 1. The second type absorption heat pump has the conditions of complex system, high cost, high maintenance cost and equipment corrosion. Besides water systems, the working medium has pollution risks to the environment. In this large context, the bomb-heating refrigeration technology is an environmentally friendly alternative refrigeration technology with greater performance potential that has been proposed in recent years. The synergistic heat pump system based on the elastic heat principle can theoretically realize better performance than a second-class absorption heat pump. However, how to apply the heat pump system to the synergistic heat pump system still has no corresponding scheme.

Disclosure of Invention

The invention aims to provide a thermal drive type elastic heat pump circulation method and system aiming at the problem of low recycling efficiency of industrial waste heat through synergistic heating in the prior art, so that low-grade heat energy can be better utilized.

In order to achieve the purpose, the invention has the following technical scheme:

a thermal drive type elastic heat pump cycle method, comprising the steps of:

the first process is as follows: the temperature of the medium-temperature driving group memory alloy is T_gThe medium-temperature heat source heats, and provides driving force required by the loading process for the high-temperature heat pump group memory alloy through the mechanical coupling part; the memory alloy of the high-temperature heat pump set is loaded by the memory alloy of the medium-temperature driving set to be transformed into martensite, and the temperature in the phase transformation process is raised to the temperature T of the high-temperature heat sink_hThe above;

the second process: medium temperature drive set memory alloy retention T_gThe temperature outputs a driving force, and simultaneously the heat of the memory alloy of the high-temperature heat pump set is discharged into a high-temperature heat sink, so that the output of high-grade heat energy is realized;

the third process: the temperature of the medium-temperature drive group memory alloy is T_cThe memory alloy of the high-temperature heat pump set is unloaded through the mechanical coupling part, and the temperature of the memory alloy of the high-temperature heat pump set is reduced to be lower than the temperature T of the medium-temperature heat source in the unloading phase change process_g；

A fourth process: the temperature of the memory alloy of the high-temperature heat pump set is T_gThe medium temperature heat source is used for heating.

Austenite termination temperature T of the high temperature heat pump set memory alloy_af2Lower than temperature T of medium-temperature heat source_gBut T is_af2The austenite termination temperature T is higher than that of the medium-temperature drive group memory alloy_af1Martensite finish temperature T of medium temperature drive group memory alloy_mf1Temperature T higher than normal temperature heat sink_c。

The invention also provides a heat pump system for realizing the heat-driven elastic heat pump circulation method, which comprises three heat sources, namely a medium-temperature driving group memory alloy, a high-temperature heat pump group memory alloy, a medium-temperature heat source, a high-temperature heat sink and a normal-temperature heat sink;

austenite termination temperature T of the high temperature heat pump set memory alloy_af2Lower than temperature T of medium-temperature heat source_gBut T is_af2The austenite termination temperature T is higher than that of the medium-temperature drive group memory alloy_af1Martensite finish temperature T of medium temperature drive group memory alloy_mf1Temperature T higher than normal temperature heat sink_c(ii) a The medium-temperature driving group memory alloy and the high-temperature heat pump group memory alloy are connected through a mechanical coupling part, and the medium-temperature driving group memory alloy and the high-temperature heat pump group memory alloy are respectively connected with three heat sources through pipelines;

one end of the medium-temperature driving group memory alloy is fixedly connected with the mechanical coupling part, and the other end of the medium-temperature driving group memory alloy is fixedly connected with the rack; one end of the high-temperature heat pump set memory alloy is fixedly connected with the mechanical coupling part, and the other end of the high-temperature heat pump set memory alloy is fixedly connected with the rack;

the total length of the memory alloy of the medium-temperature driving group and the memory alloy of the high-temperature heat pump group is restricted by the frame.

As a preferable aspect of the heat pump system: a second three-way valve is arranged on a pipeline between the memory alloy of the medium temperature driving group and the normal temperature heat sink and is connected with a medium temperature heat source through a pipeline; the medium-temperature driving group memory alloy is also respectively connected with a normal-temperature heat sink and a medium-temperature heat source through a second circulating pump and a third three-way valve in sequence; a fourth three-way valve is arranged on a pipeline between the memory alloy of the high-temperature heat pump set and the high-temperature heat sink and is connected with a medium-temperature heat source through a pipeline; the high-temperature heat pump group memory alloy is also respectively connected with a high-temperature heat sink and a medium-temperature heat source through a first circulating pump and a fifth three-way valve in sequence.

As a preferable aspect of the heat pump system:

a second three-way valve is arranged on a pipeline between the memory alloy of the medium temperature driving group and the normal temperature heat sink and is connected with a medium temperature heat source through a pipeline; the medium-temperature driving group memory alloy is also respectively connected with a normal-temperature heat sink and a medium-temperature heat source through a second circulating pump and a third three-way valve in sequence; when the phase change of the high-temperature heat pump set memory alloy is heated and needs heat extraction, a heat exchange fluid enters the high-temperature heat pump set memory alloy from the medium-temperature heat source through the four-way valve, the first circulating pump and the four-way valve, absorbs heat and then enters the high-temperature heat sink; when the high-temperature heat pump set memory alloy needs to absorb heat during phase change and temperature reduction, the heat exchange fluid is absorbed into the high-temperature heat pump set memory alloy from the high-temperature heat sink and enters the medium-temperature heat source through the four-way valve, the first circulating pump and the four-way valve.

As a preferable aspect of the heat pump system:

a second three-way valve is arranged on a pipeline between the memory alloy of the medium temperature driving group and the normal temperature heat sink and is connected with a medium temperature heat source through a pipeline; the medium-temperature driving group memory alloy is also respectively connected with a normal-temperature heat sink and a medium-temperature heat source through a second circulating pump and a third three-way valve in sequence; the memory alloy of the high-temperature heat pump set operates an active regenerative heat pump cycle, the hot end of the high-temperature heat pump set is connected with a high-temperature heat sink, and the cold end of the high-temperature heat pump set is respectively connected with a medium-temperature heat source or a medium-temperature drive set memory alloy through a four-way valve, a first circulating pump and a first three-way valve;

the four-way valve has two communication modes:

when the phase change temperature rise of the memory alloy of the high-temperature heat pump set needs heat extraction, the heat exchange fluid enters the memory alloy of the high-temperature heat pump set from the medium-temperature heat source through the medium-temperature driving set memory alloy, the first three-way valve, the four-way valve, the first circulating pump and the four-way valve in sequence, absorbs heat and then enters a high-temperature heat sink; when the high-temperature heat pump set memory alloy needs to absorb heat during phase change cooling, the heat exchange fluid is absorbed into the high-temperature heat pump set memory alloy from the high-temperature heat sink and then enters the medium-temperature heat source through the four-way valve, the first circulating pump, the four-way valve and the first three-way valve in sequence.

As a preferable aspect of the heat pump system:

the medium-temperature driving group memory alloy is connected with a medium-temperature heat source through a first one-way valve, and a second one-way valve is arranged between the medium-temperature driving group memory alloy and a second three-way valve; the two modes of the communication heat exchange between the medium-temperature driving group memory alloy and the medium-temperature heat source and the communication heat exchange between the medium-temperature driving group memory alloy and the normal-temperature heat sink are realized through the second three-way valve, the third three-way valve, the second one-way valve and the second circulating pump.

As a preferable aspect of the heat pump system: the high-temperature heat pump group memory alloy realizes the phase transformation from austenite to martensite by compressive stress, tensile stress, torsional stress or the combination of the driving loading stress forms, and can be transformed from austenite to martensite after the driving loading stress is removed, so as to obtain the refrigerating capacity; the driving loading stress of the high-temperature heat pump group memory alloy is provided by the medium-temperature driving group memory alloy in the process of heating and transforming martensite into austenite, and the medium-temperature driving group memory alloy provides compressive stress, tensile stress or torsional stress when being heated by utilizing the shape memory effect.

As a preferable aspect of the heat pump system: the mechanical coupling component is a part for transmitting linear stretching force, linear compression force and torsional torque, or a device for converting the linear stretching force, the linear compression force and the torsional torque of the memory alloy of the medium-temperature driving group into any one of the driving forces required by the memory alloy of the high-temperature heat pump group.

As a preferable aspect of the heat pump system:

the medium temperature heat source is at a temperature of T_gThe solid or the closed medium temperature fluid or any one of a plate heat exchanger, a plate-fin heat exchanger, a tube-fin heat exchanger, a micro-channel heat exchanger and a shell-and-tube heat exchanger which are contacted with the medium temperature fluid; the heat source of the medium-temperature heat source comprises solar energy, terrestrial heat, waste heat of an automobile engine or exhaust, industrial waste heat and waste heat of electronic products.

Compared with the prior art, the invention has the following beneficial effects: using a set of martensite finish temperatures T_mf1Higher than the normal temperature heat sink temperature T_c(i.e., room temperature), and austenite finish temperature T_af1Lower than the medium temperature heat source temperature T_gThe memory alloy of (2) is used as the memory alloy of the medium-temperature driving group. Using a set of austenite finish temperatures T_af2Also lower than the medium temperature heat source temperature T_gBut T_af2Higher than T_af1The memory alloy is used as the memory alloy of the high-temperature heat pump set. The low-grade medium-temperature heat source is used for supplying heat to the medium-temperature drive group memory alloy, and the medium-temperature drive group memory alloy is radiated through the normal-temperature heat sink, so that the memory alloy can be used for periodically memorizing the high-temperature heat pump groupThe alloy provides driving force to make the high-temperature heat pump group memory alloy raise the heat from the medium-temperature heat source to T_h(higher than T)_g) The high-temperature heat sink achieves the aim of improving the grade of the medium-temperature heat source. The invention adopts the medium-temperature driving group memory alloy as the driver to replace the traditional special motor driving mode, not only has the advantage of small mass ratio of the driving group to the heat pump group, but also has the advantage that the medium-temperature driving group memory alloy can be driven by a heat source at about 60 ℃, thereby leading the system to better utilize low-grade heat energy, such as solar energy, terrestrial heat, automobile waste heat, industrial waste heat, electronic product waste heat and the like. Compared with the existing heat-driven elastic heat refrigeration technology, the invention has a medium-temperature heat source, a high-temperature heat sink and a normal-temperature heat sink at room temperature, can realize the synergy of a low-grade heat source at about 60 ℃ into heat energy at more than 100 ℃ for utilization, and is different from the form of refrigeration driven by the low-grade heat source at 60-80 ℃.

Drawings

FIG. 1 is a schematic diagram of the present invention characterized on a temperature-stress phase diagram;

FIG. 2 is a schematic diagram of a thermal drive type bolometric heat pump system fluid cycle of the single-stage heat pump;

FIG. 3 is a schematic diagram of a fluid cycle of a first active regenerative cycle thermal drive type elasto-thermal heat pump system;

fig. 4 is a schematic diagram of a fluid cycle of a second active regenerative cycle thermal drive type elasto-thermal heat pump system.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The shape memory alloy (memory alloy for short) related in the heat-driven elastic heat pump circulation method and system of the invention provides the characteristic of stress strain when the martensite is changed into the austenite under the heat drive, and the memory alloy has the characteristic of heat release and reverse phase transformation and heat absorption when the austenite is changed into the martensite under the stress drive. In memory alloys, there are at least two crystal structures (phases), namely a high temperature phase at zero stress (austenite) and a low temperature phase at zero stress (martensite).

In the system of the present invention, there are two groups of memory alloys, which are: a group of medium temperature driving group memory alloys, the martensite finish temperature T thereof_mf1Higher than the normal temperature heat sink temperature T_c(i.e., room temperature), and austenite finish temperature T_af1Lower than the medium temperature heat source temperature T_gAustenite finish temperature T of memory alloy of another group of high temperature heat pump group_af2Lower than the medium temperature heat source temperature T_gBut T_af2Higher than T_af1. The memory alloy of the driving group and the memory alloy of the refrigerating group are connected through mechanical coupling, and the total length of the memory alloy of the driving group and the memory alloy of the refrigerating group is restrained through the frame. For the sake of discussion, it is assumed that the cross sections of the memory alloy of the driving group and the memory alloy of the refrigerating group are consistent, so under the corresponding constraint conditions, the stress of the memory alloy of the driving group and the memory alloy of the refrigerating group connected with the memory alloy of the driving group is equal in time, the strain is equal in time, and the directions are opposite.

In the first embodiment shown in fig. 2, the medium temperature driving group memory alloy 106 is communicated with the normal temperature heat sink 103 or the medium temperature heat source 102 through a second three-way valve 105-2 and a third three-way valve 105-3, and the two ways are driven by a second circulating pump 104-2; the high-temperature heat pump group memory alloy 107 is communicated with the high-temperature heat sink 101 or the medium-temperature heat source 102 through a fourth three-way valve 105-4 and a fifth three-way valve 105-5, and the two ways are driven by a first circulating pump 104-1. The cycle is divided into 4 processes:

the first process is as follows: the second and third three-way valves 105-2 and 105-3 are adjusted to a mode in which the medium temperature driving group memory alloy 106 communicates with the medium temperature heat source 102, the second circulation pump 104-2 is activated, the first circulation pump 104-1 is turned off, and after the medium temperature driving group memory alloy 106 is heated from the initial temperature (a1) to the austenite transformation temperature (a2), the memory alloy starts to transform from martensite to austenite (a2 → A3), and contraction occurs, stress increases, and high loading startsThe heat pump set memory alloy 107. Due to the temperature T of the medium-temperature heat source_gAbove the austenite finish temperature T of the drive group memory alloy_af1After the phase transformation of the memory alloy in the driving group is finished, the temperature is continuously increased (A3 → A4), and the temperature of the memory alloy in the driving group is maintained at T after the austenite phase transformation is finished_g(A4) In that respect The heat pump group memory alloy is loaded by loading stress provided by the medium-temperature driving group memory alloy 106, austenite is changed into martensite, heat is released in the phase change process, and the temperature is increased;

the second process: the fourth three-way valve 105-4 and the fifth three-way valve 105-5 are adjusted to a mode that the high-temperature heat pump set memory alloy 107 is communicated with the high-temperature heat sink 101, the first circulating pump 104-1 is started, the high-temperature heat pump set memory alloy 107 discharges all heat generated by phase change to the high-temperature heat sink 101, and the temperature of the memory alloy is reduced to the temperature of the high-temperature heat sink. During this stage, the second circulation pump continues to operate, and the medium-temperature driving group memory alloy 106 continues to provide the driving force (A4).

The third process: the second three-way valve 105-2 and the third three-way valve 105-3 are adjusted to a mode that the medium-temperature driving group memory alloy 106 is communicated with the normal-temperature heat sink 103, the second circulating pump 104-2 is started, the first circulating pump 104-1 is closed, the medium-temperature driving group memory alloy 106 is cooled, when the temperature is reduced to the martensite phase transition temperature (A5), the medium-temperature driving group memory alloy 106 starts to change from austenite to martensite (A5 → A6), the temperature and the stress are both reduced, and the heat pump group memory alloy starts to be unloaded. Due to the normal temperature heat sink temperature T_cBelow the martensite finish temperature T of the drive group memory alloy_mf1After the phase transformation of the memory alloy of the driving group is finished, the temperature is continuously reduced (A6 → A1) and is maintained at T_c(A1) In that respect The heat pump group memory alloy is unloaded by the medium-temperature driving group memory alloy, the martensite is changed into the austenite, the heat is absorbed in the phase change process, and the temperature is reduced;

a fourth process: the fourth three-way valve 105-4 and the fifth three-way valve 105-5 are adjusted to a mode that the high-temperature heat pump set memory alloy 107 is communicated with the medium-temperature heat source 102, the first circulating pump 104-1 is started, the second circulating pump 104-2 is closed, the high-temperature heat pump set memory alloy 107 completely transmits cold energy generated by phase change to the medium-temperature heat source 102, the memory alloy absorbs heat from the medium-temperature heat source, the temperature rises to the temperature of the medium-temperature heat source, and the whole circulation is completed.

In a second embodiment shown in FIG. 3, the high temperature heat pump set memory alloy employs an active regenerative cycle to increase the heat pump heat supply delta T (defined as the delta T between the high temperature heat sink temperature and the medium temperature heat source temperature)_h-T_g) That is, the memory alloy of the heat pump set has a temperature distribution from Tg to Th, a hot end is close to the high-temperature heat sink 101, and the temperature is close to T_h(C1) Near the intermediate heat source 102 is the cold side, at a temperature near T_g(B1) In that respect Before the circulation begins, the temperature of the medium-temperature driving group memory alloy 106 is T from the normal temperature heat sink_cAfter the cooling of the normal temperature fluid is completed, it is located at a 1. The cycle comprises the following four processes:

the first process is as follows: the second and third three-way valves 105-2 and 10-3 are adjusted to a mode in which the medium temperature drive group memory alloy 106 communicates with the medium temperature heat source 102, the second circulation pump 104-2 is activated, the first circulation pump 104-1 is turned off, and after the medium temperature drive group memory alloy 106 is heated from the initial temperature (a1) to its austenite phase transition temperature (a2), the memory alloy begins to change from martensite to austenite (a2 → A3), and contraction occurs, stress increases, and loading of the high temperature heat pump group memory alloy begins. Due to the temperature T of the medium-temperature heat source_gAbove the austenite finish temperature T of the drive group memory alloy_af1After the phase transformation of the memory alloy in the driving group is finished, the temperature is continuously increased (A3 → A4), and the temperature of the memory alloy in the driving group is maintained at T after the austenite phase transformation is finished_g(A4) In that respect The heat pump group memory alloy is loaded by loading stress provided by the medium-temperature driving group memory alloy 106 (B1 → B2, C1 → C2), when the stress is increased to martensite phase transformation stress (B2, C2), the heat pump group memory alloy starts to change from austenite to martensite (B2 → B3, C2 → C3), and the phase transformation process releases heat along with the simultaneous increase of the temperature and the stress. The stress continues to increase after the phase transformation (but at this point the temperature does not rise) until the maximum stress state is reached (B4, C4).

The second process: the second three-way valve 105-2 and the third three-way valve 105-3 are adjusted to a mode that the medium temperature driving group memory alloy 106 is communicated with the medium temperature heat source 102, the second circulating pump 104-2 is started, and the medium temperature driving group memory alloy 106 keeps T_gTemperature (A4). At the same timeThe four-way valve 110 connects the outlet of the first circulation pump 104-1 with the high-temperature heat pump set memory alloy 107, the first circulation pump 10-1 is started to work, and the temperature is T_gThe medium-temperature fluid flows out from the medium-temperature heat source, flows through the four-way valve 110, the first circulating pump 104-1 and the four-way valve 110, enters the high-temperature heat pump group memory alloy 107, absorbs heat from the memory alloy, and flows into the high-temperature heat sink after the temperature of the fluid is raised. The high temperature heat pump group memory alloy 107 is cooled and there is a temperature gradient along the flow direction of the fluid, where the cold end (inlet end) is cooled to T_g(B4 → B5), the hot end (outlet end) is cooled to T under the condition of proper control flow_h(C4→C5)。

The third process: the second three-way valve 105-2 and the third three-way valve 105-3 are adjusted to a mode that the medium-temperature driving group memory alloy 106 is communicated with the normal-temperature heat sink 103, the second circulating pump 104-2 is started, the first circulating pump 104-1 is closed, the medium-temperature driving group memory alloy 106 is cooled, when the temperature is reduced to the martensite phase transition temperature (A5), the medium-temperature driving group memory alloy 106 starts to change from austenite to martensite (A5 → A6), the temperature and the stress are both reduced, and the heat pump group memory alloy starts to be unloaded. Due to the temperature T of the ambient temperature heat sink 103_cBelow the martensite finish temperature T of the drive group memory alloy_mf1After the phase transformation of the memory alloy of the driving group is finished, the temperature is continuously reduced (A6 → A1) and is maintained at T_c(A1) In that respect During the unloading process of the high-temperature heat pump group memory alloy 107, the stress is continuously reduced to austenite phase transformation critical stress (B5 → B6, C5 → C6), the heat pump group memory alloy starts to transform from martensite to austenite (B6 → B7, C6 → C7), and the phase transformation process absorbs heat and simultaneously reduces the temperature and the stress. The stress continues to decrease after the phase transformation (but at this point the temperature no longer drops) until zero driving stress (B8, C8).

A fourth process: the second and third three-way valves are closed and the second circulation pump 104-2 stops working. The four-way valve 110 connects the outlet of the first circulating pump 104-1 with the medium temperature heat source 102, the first circulating pump 104-1 is started to work, the heat exchange fluid which completes high temperature heat supply flows out from the high temperature heat sink, and flows through the high temperature heat pump set memory alloy 107 with reduced temperature after the phase change is finished, the high temperature heat pump set memory alloy 107 transmits the cold energy absorbed by the phase change into the fluid, and the four-way valve 1 is used for transmitting the cold energy absorbed by the phase change into the fluid10. The first circulating pump 104-1 and the four-way valve 110 finally flow back to the medium-temperature heat source, and the fluid with the reduced temperature absorbs heat from the medium-temperature heat source to enable the temperature of the fluid to reach T again_g. The high temperature heat pump group memory alloy is heated 107 and there is a temperature gradient along the flow direction of the fluid, where the cold end is heated to T_g(B8 → B1), the hot end is heated to T under the condition of proper flow control_h(C8→C1)。

After the fourth process is finished, the first process is returned to and the next cycle is started.

The basic form of the third system shown in fig. 4 is similar to that of the scheme shown in fig. 3, and the core difference is that the maintenance of the medium-temperature-driven group memory alloy for maintaining the T is realized by only starting the first circulating pump 104-1 in the second process of the second system form by introducing the first three-way valve 105-1, the first one-way valve 109-1, the second one-way valve 109-2 and corresponding pipelines_gThe memory alloy of the temperature and high-temperature driving group has two functions of exhausting heat to the high-temperature heat sink, so that the energy consumption of the second circulating pump 104-2 is saved. In addition, the first process and the third process are consistent with the scheme. The following describes the specific steps of the second and fourth processes of the system operating in a loop.

The second process: the second circulation pump 104-2 is closed, and the second three-way valve 10-2 and the third three-way valve 105-3 are closed. The first three-way valve 105-1 is switched to a mode that the medium-temperature driving group memory alloy 106 is communicated with the four-way valve 110, the four-way valve 110 is switched to a mode that the outlet of the first circulating pump 104-1 is communicated with the high-temperature heat pump group memory alloy 107, and the first circulating pump 104-1 is started. The medium-temperature fluid with the temperature Tg flows out of the medium-temperature heat source, flows through the medium-temperature driving group memory alloy 106, the first three-way valve 105-1, the four-way valve 110, the first circulating pump 104-1 and the four-way valve 110, enters the high-temperature heat pump group memory alloy 107, absorbs heat from the high-temperature heat pump group memory alloy 107, and flows into the high-temperature heat sink 103 after the fluid is heated. The high temperature heat pump group memory alloy 107 is cooled and there is a temperature gradient along the flow direction of the fluid, where the cold end (inlet end) is cooled to T_g(B4 → B5), the hot end (outlet end) is cooled to T under the condition of proper control flow_h(C4→C5)。

A fourth process: the second and third three-way valves are closed,the second circulation pump 104-2 is stopped. The first three-way valve 105-1 is switched to a mode that the medium-temperature heat source is communicated with the four-way valve 110, the four-way valve 110 is switched to a mode that the outlet of the first circulating pump 104-1 is communicated with the first three-way valve 105-1, and the first circulating pump 104-1 is started. The heat exchange fluid for completing high-temperature heat supply flows out from the high-temperature heat sink, flows through the high-temperature heat pump group memory alloy 107 with the temperature reduced after the phase change is finished, the high-temperature heat pump group memory alloy 107 transmits the cold energy absorbed by the phase change into the fluid, the fluid finally flows back to the medium-temperature heat source 102 through the four-way valve 110, the first circulating pump 104-1, the four-way valve 110 and the first three-way valve 105-1, and the fluid with the reduced temperature absorbs heat from the medium-temperature heat source 102 to enable the temperature of the_g. The high temperature heat pump group memory alloy 107 is heated and there is a temperature gradient along the flow direction of the fluid, where the cold end is heated to T_g(B8 → B1), the hot end is heated to T under the condition of proper flow control_h(C8→C1)。

In the four processes of the scheme, under the combined action of the first check valve, the second three-way valve and the third three-way valve, when the normal-temperature heat sink does not participate in circulation, the flow path is cut off, so that the heat exchange fluid in the normal-temperature heat sink is not mixed with the heat exchange fluid in the circulation.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the technical solution of the present invention, and it should be understood by those skilled in the art that the technical solution can be modified and replaced by a plurality of simple modifications and replacements without departing from the spirit and principle of the present invention, and the modifications and replacements also fall within the protection scope defined by the claims.