Elastocaloric heat pump, motor vehicle with an elastocaloric heat pump and method for operating an elastocaloric heat pump

Abstract

Elastocaloric heat pump (100) with an elastocaloric arrangement (10), wherein the elastocaloric arrangement (10) comprises at least one elastocaloric element (14) and a receiving device (11) with a first receiving part (12) and a second receiving part (13) and a spring device (15), wherein the at least one elastocaloric element (14) is clamped between the first receiving part (12) and the second receiving part (13), wherein the spring device (15) is designed to exert a spring force (20) on the at least one elastocaloric element (14), wherein the at least one elastocaloric element (14) has a pre-stretch (23) not equal to zero in a force equilibrium of the spring force (20) and a restoring force (22) of the elastocaloric element (14) opposite to the spring force (20), characterized in that the at least one elastocaloric element (14) has a predetermined and / or material-dependent,for an elastocaloric effect usable strain range (26) with an upper limit (28) and a lower limit (27), wherein the pre-stretch (23) lies within the strain range (26), wherein the amount of the lower limit (27) is between 0.5% and 5%, preferably between 0.7% and 2%, more preferably 1%, and / or that the amount of the upper limit (28) is between 2% and 20%, preferably between 3% and 10%, more preferably between 4% and 7.5%, particularly preferably 4.5%.

Description

[0001] The present invention relates to an elastocaloric heat pump with an elastocaloric arrangement, wherein the elastocaloric arrangement comprises at least one elastocaloric element and a receiving device with a first receiving part and a second receiving part.

[0002] Furthermore, the present invention relates to a motor vehicle with an elastocaloric heat pump and a method for operating an elastocaloric heat pump.

[0003] Instead of or in addition to conventional compression heat pumps, so-called elastocaloric heat pumps can be used in motor vehicles to increase efficiency. An elastocaloric heat pump utilizes the elastocaloric effect, whereby the cyclic deformation of an elastocaloric material causes a reversible temperature change, which can be used to transfer heat from a colder coolant stream to a warmer coolant stream.

[0004] To induce the elastocaloric effect, the elastocaloric material must be brought into a material-dependent strain range of, for example, 1% to 10%. Actuators that induce cyclic strain in the elastocaloric material must therefore apply additional high forces to bring the elastocaloric material into the usable strain range in the first place. These high forces must be permanently absorbed by the actuators and their joints. This leads to increased friction losses and thus to significantly reduced efficiency. Furthermore, the actuator joints must be dimensioned accordingly large, which requires a massive design and construction of all components.

[0005] DE 10 2015 121 657 A1 discloses a method and a device for operating cycle-based systems. The cycle-based system comprises a hot-side reservoir and a cold-side reservoir for a fluid and at least one heat exchanger unit with mechanocaloric material, wherein heat transfer takes place between the mechanocaloric material and the fluid. The heat transfer between the mechanocaloric material and the fluid occurs essentially by means of latent heat transfer.

[0006] DE 10 2018 207 577 A1 discloses a heat exchange device comprising a heat sink, a heat source, at least one elastocaloric element, and at least one actuator. The elastocaloric element is in contact with the heat source, and the actuator is configured to deform the associated elastocaloric element, thereby moving it away from the heat source and bringing it into contact with the heat sink. A vacuum is formed between the heat source and the heat sink as thermal insulation.

[0007] WO 2019 / 0 166 251 A1 discloses an elastocaloric element consisting of three interconnected layers, wherein the elastocaloric element is cyclically subjected to a bending stress. A first layer consists of a first elastocaloric material that has a coefficient of performance under compressive stress that lies above a first threshold. A second layer consists of a second elastocaloric material that has a coefficient of performance under tensile stress that lies above a second threshold. Between these two layers, a third layer is arranged, which is designed as a spring sheet. This third layer consists of a non-elastocaloric material.

[0008] WO 2019 / 0 228 789 A1 relates to a heat exchange device comprising a heat source and a heat sink, a heat exchanger that can be alternately connected to the heat source and the heat sink, and a barocaloric element connected to the heat exchanger. A shape memory material is provided that is configured to exert pressure on the barocaloric element upon its temperature-induced deformation.

[0009] DE 10 2018 208 350 A1 relates to a heat exchange device comprising a heat source and a heat sink, a heat exchanger that can be alternately connected to the heat source and the heat sink, and a barocaloric element connected to the heat exchanger. Furthermore, a shape memory material is provided that is configured to exert pressure on the barocaloric element upon its temperature-induced deformation.

[0010] DE 10 2018 213 505 A1 relates to a device for heat exchange, which comprises a heat source, a heat sink, at least one elastocaloric element, at least one magnetic yoke and at least one magnetic armature, wherein the magnetic yoke and the magnetic armature form a magnetic circuit through which the magnetic armature can be moved and the magnetic armature exerts a mechanical stress on the associated elastocaloric element, as a result of which the elastocaloric element expands and this elastocaloric element can thereby come into contact with the heat sink and the elastocaloric element can deform again and thereby come into contact with the heat source, wherein the at least one elastocaloric element is subjected to a mechanical prestress, in which the elastocaloric element is clamped by the magnetic armature, wherein the prestress is below a conversion threshold for the at least one elastocaloric element.

[0011] DE 10 2009 040 523 A1 relates to a heat engine with a rotor rotatable about a rotational axis, comprising at least one shape memory element that can be adjusted between at least one heat source and at least one heat sink by rotating the rotor. According to the invention, the shape memory element is associated with at least one energy storage device arranged on the rotor, which can be charged in the heat source by contracting the shape memory element and discharged at a defined circumferential position outside the heat source.

[0012] The present invention is based on the object of providing an elastocaloric heat pump with improved efficiency and in which friction losses are reduced.

[0013] To achieve the object underlying the invention, an elastocaloric heat pump with an elastocaloric arrangement is proposed, wherein the elastocaloric arrangement comprises at least one elastocaloric element and a receiving device with a first receiving part and a second receiving part and a spring device, wherein the at least one elastocaloric element is clamped between the first receiving part and the second receiving part, wherein the spring device is designed to exert a spring force on the at least one elastocaloric element, wherein the at least one elastocaloric element has a pre-stretching not equal to zero in a force equilibrium of the spring force and a restoring force of the elastocaloric element opposite to the spring force.

[0014] The elastocaloric heat pump according to the invention comprises an elastocaloric arrangement. Furthermore, the elastocaloric heat pump can also comprise additional components, such as a housing, channels for a cooling medium, and actuators for deforming or stretching, i.e., compressing and / or stretching, the at least one elastocaloric element.

[0015] The elastocaloric arrangement of the elastocaloric heat pump comprises at least one elastocaloric element and a receiving device with a first receiving part and a second receiving part. The at least one elastocaloric element is clamped between the first receiving part and the second receiving part. This means, in particular, that the elastocaloric element is firmly connected to the first receiving part and the second receiving part, so that forces can be exerted on the elastocaloric element via the first receiving part and the second receiving part.

[0016] Furthermore, according to the invention, a spring device is provided which is configured to exert a spring force directly or indirectly on the at least one elastocaloric element. The elastocaloric arrangement or the arrangement of the components of the elastocaloric arrangement is designed such that, in a neutral state, a force equilibrium exists between the spring force exerted directly or indirectly by the spring device on the elastocaloric element and a restoring force of the elastocaloric element opposite to the spring force. In this neutral state, i.e., in the state of force equilibrium, the elastocaloric element has a pre-extension other than 0. In other words, in the force equilibrium in the neutral state, the elastocaloric element is deformed compared to a state in which no forces are applied.

[0017] The spring device thus provides at least part of the preload force that must be applied to bring the elastocaloric material of the at least one elastocaloric element into the usable expansion range. The actuators that may be provided in the elastocaloric heat pump and that cause the cyclic deformation or expansion, i.e., compression and / or extension, of the at least one elastocaloric element, therefore no longer need to generate or absorb this preload force already applied by the spring device. Thus, the joints of the actuators are subjected to less stress, which leads to lower friction losses and thus to increased efficiency of the elastocaloric heat pump.

[0018] During operation, the actuators provided, if any, essentially only have to apply those forces which are required for the cyclic deformation or extension of the elastocaloric element in the technically usable extension range.

[0019] Depending on the pre-strain setting, friction losses can be reduced by a factor of up to seven or more. Furthermore, the forces acting on the actuator(s) and the associated components can be reduced by a factor of eight or more. The extent of the friction loss savings and the force reduction in the components depends on the hysteresis spread of the elastocaloric material of at least one elastocaloric element, as well as the pre-load required to induce the elastocaloric effect.

[0020] It is preferably provided that the elastocaloric arrangement comprises a plurality of elastocaloric elements, wherein the plurality of elastocaloric elements are clamped between the first receiving part and the second receiving part.

[0021] In one embodiment, the elastocaloric element or the elastocaloric elements may be formed, for example, as tubes, rods or the like and may be clamped substantially in a parallel alignment between the first receiving part and the second receiving part.

[0022] It is preferably provided that the spring device is connected to the first receiving part and the second receiving part in such a way that the spring force of the spring device is transmitted via the first receiving part and the second receiving part to the at least one elastocaloric element.

[0023] Thus, it can be provided that the spring device does not transmit the spring force directly to the elastocaloric element, but that the spring device exerts a force on the first receiving part and the second receiving part and that the spring force is transmitted along this force path to the at least one elastocaloric element clamped between the first receiving part and the second receiving part.

[0024] The first receiving part and the second receiving part can be arranged so as to be movable relative to one another and, in particular, can be moved toward and away from one another. Cyclical movements of the receiving parts toward or away from one another can cyclically stretch the at least one elastocaloric element, i.e., extend and / or compress it. For these cyclical movements, one or more actuators can be provided, which are connected to the first and / or second receiving part or apply corresponding forces to the first and / or second receiving part.

[0025] The elastocaloric arrangement and in particular the spring device can be designed to subject the at least one elastocaloric element to tensile or compressive stress.

[0026] The pre-stretching is accordingly a pre-stretching or pre-compression. If the spring device pre-loads the at least one elastocaloric element in compression, the spring device can be configured to pull or push the first receiving part and the second receiving part toward each other. If the spring device pre-loads the at least one elastocaloric element in tension, the spring device can be configured to pull or push the first receiving part and the second receiving part away from each other.

[0027] Preferably, it can be provided that the first receiving part has a first spring stop surface and that the second receiving part has a second spring stop surface, wherein the spring device is arranged between the first spring stop surface and the second spring stop surface.

[0028] The first spring stop surface and the second spring stop surface can be arranged substantially parallel to each other and / or opposite each other. The spring device is then arranged between the first spring stop surface and the second spring stop surface. Depending on whether the spring device is designed as a compression or tension spring, it pushes the first spring stop surface and the second spring stop surface, and thus also the first receiving part and the second receiving part, apart or pulls them towards each other, whereby the at least one elastocaloric element arranged between the first receiving part and the second receiving part is preloaded either in tension or in compression.

[0029] According to the invention, it is provided that the at least one elastocaloric element has a predetermined and / or material-dependent strain range which can be used for an elastocaloric effect and which has an upper limit and a lower limit, and wherein the pre-strain lies within the strain range.

[0030] The strain indicates the percentage change in length of at least one elastocaloric element. The change in length can be either compression or stretching.

[0031] In principle, the elastocaloric element can exhibit an elastocaloric effect over a very wide strain range. However, elastocaloric materials usually have a limited strain range, outside of which the technical utilization of the elastocaloric effect cannot be efficiently achieved.

[0032] The usable expansion range is usually material-dependent and can be determined or specified by a specialist, depending on the design of the elastocaloric heat pump.

[0033] The usable expansion range has a lower limit and an upper limit. The pre-strain preferably lies within the expansion range, i.e., between the lower limit and the upper limit. This has the advantage that the actuator(s) of the elastocaloric heat pump no longer have to apply the necessary prestress to bring the elastocaloric element into the technically usable expansion range. The actuators only need to be designed to deform the elastocaloric element within the usable expansion range in order to make the elastocaloric effect technically usable. The forces required for this are significantly lower than the forces that would have to be applied not only to carry out the expansion within the usable expansion range, but also to simultaneously apply the prestress forces necessary to bring the elastocaloric element into the usable expansion range in the first place.

[0034] Furthermore, it can preferably be provided that the spring force in the force equilibrium corresponds to the restoring force of the elastocaloric element at the lower limit of the elongation range, or that the spring force in the force equilibrium corresponds to the restoring force of the elastocaloric element at the upper limit of the elongation range, or that the spring force in the force equilibrium corresponds to a value between the restoring force of the elastocaloric element at the lower limit of the elongation range and the restoring force of the elastocaloric element at the upper limit of the elongation range.

[0035] If, in the force equilibrium, the spring force corresponds to the restoring force of the elastocaloric element at the lower limit of the expansion range, the actuator(s) of the elastocaloric heat pump are designed to cyclically expand the elastocaloric element beyond the pre-strain, i.e. to stretch or compress it.

[0036] If the spring force in the force equilibrium corresponds to the restoring force of the elastocaloric element at the upper limit of the expansion range, the actuator(s) of the elastocaloric heat pump are designed to cyclically reduce the pre-strain, ie to reduce the stretching or compression.

[0037] However, in a preferred embodiment, it is provided that the spring force in force equilibrium corresponds to a value between the restoring force of the elastocaloric element at the lower limit of the elongation range and the restoring force of the elastocaloric element at the upper limit of the elongation range.

[0038] In this case, the heat pump's actuator(s) are designed to cyclically vary the at least one elastocaloric element around the pre-stretch value, i.e., to cyclically decrease and increase the elastocaloric element's elongation relative to the pre-stretch value. The forces exerted by the actuators are then at their lowest in this case, allowing friction losses to be significantly reduced.

[0039] With further advantage, it can be provided that the spring force in force equilibrium corresponds to an average value of the restoring force of the elastocaloric element at the lower limit of the elongation range and the restoring force of the elastocaloric element at the upper limit of the elongation range.

[0040] It is provided that the amount of the lower limit is between 0.5% and 5%, preferably between 0.7% and 2%, more preferably 1%, and / or that the amount of the upper limit is between 2% and 20%, preferably between 3% and 10%, more preferably between 4% and 7.5%, particularly preferably 4.5%.

[0041] Thus, the technically usable elongation range can be in particular between 0.5% and 20%, preferably between 0.7% and 7.5%, more preferably between 1% and 4.5%.

[0042] Furthermore, it can be provided that the pre-stretching is a positive elongation, in particular a stretching, or that the pre-stretching is a negative elongation, in particular a compression.

[0043] If the pre-strain is a positive strain, i.e., a stretch, the at least one elastocaloric element is pre-loaded in tension. If, however, the pre-strain is a negative strain, i.e., a compression, the at least one elastocaloric element is pre-loaded in compression.

[0044] With further advantage, it can be provided that the spring device comprises a tension spring or a compression spring.

[0045] Furthermore, it can be provided that the spring device comprises a gas spring and / or a disc spring and / or a hydraulic spring and / or a helical spring and / or an annular spring, and / or that at least the spring device comprises an elastocaloric material.

[0046] In particular, a spring device which comprises a gas spring is particularly advantageous.

[0047] In principle, the spring device can also comprise another elastocaloric material. This is particularly advantageous when two elastocaloric arrangements are combined. With appropriate mutual arrangement, the elastocaloric elements of the two elastocaloric arrangements can thus act as a spring device for each other.

[0048] Furthermore, it can be provided that the spring device comprises at least one, preferably several, spring elements.

[0049] The individual spring elements can be designed as a gas spring and / or disc spring and / or hydraulic spring and / or helical spring and / or ring spring and / or as an elastocaloric material.

[0050] It is further advantageous that the spring device has a degressive spring characteristic curve.

[0051] A spring characteristic curve describes the progression of spring force as a function of the spring's deflection. With a degressive spring characteristic curve, the spring force decreases proportionally the greater the spring's deflection.

[0052] It is particularly advantageous that the spring characteristic curve is essentially constant in the force equilibrium, preferably in the extension range.

[0053] In other words, the spring force is essentially constant in the force equilibrium or in the extension range and therefore independent of slight compression or extension. This means, in particular, that the actuator(s) that cyclically stretch, i.e., extend or compress, the at least one elastocaloric element need apply little or no force to extend and / or compress the spring device. The majority of the forces applied by the actuators are then used for the cyclic extension of the at least one elastocaloric element and thus for utilizing the elastocaloric effect.

[0054] With further advantage, it can be provided that the elastocaloric element has a substantially constant strain characteristic and / or a substantially constant, preferably linear, strain modulus in the force equilibrium, preferably in the strain range.

[0055] A strain characteristic is defined as the product of the strain modulus multiplied by the cross-sectional area of ​​the elastocaloric element. If the elastocaloric material of the elastocaloric element is selected such that the strain characteristic or the preferably linear strain modulus is essentially constant within the technically usable strain range, the forces required to stretch, i.e., to extend and / or compress, the elastocaloric material to utilize the elastocaloric effect are also low and primarily serve to overcome material hysteresis.

[0056] In a particularly preferred embodiment, it is therefore provided that a superposition of the spring characteristic and the extension characteristic or the extension modulus in the force equilibrium, preferably in the extension range, is substantially constant.

[0057] A superposition of the spring characteristic and the strain characteristic is understood in particular to mean a superposition of the spring characteristic and the strain modulus of the elastocaloric element multiplied by the cross-sectional area of ​​the elastocaloric element.

[0058] The superposition of the spring characteristic and the strain characteristic then describes the functional relationship between force and strain of the entire system or the elastocaloric arrangement.

[0059] If the superposition of the spring characteristic and the strain characteristic in the strain range is essentially constant, the actuators for the cyclic extension or compression and / or extension of the elastocaloric element only need to apply those forces which are necessary to overcome the hysteresis of the elastocaloric material of the elastocaloric element.

[0060] Furthermore, at least one actuator can be provided, wherein the at least one actuator is configured to cyclically stretch the at least one elastocaloric element during operation, preferably within the stretching range.

[0061] The at least one actuator, preferably at least two actuators, are further preferably connected to the first and / or the second receiving part and are configured to cyclically move the first and the second receiving part towards each other or away from each other.

[0062] A further solution to the problem underlying the invention consists in providing a motor vehicle comprising an elastocaloric heat pump as described above.

[0063] A further solution to the problem underlying the invention consists in providing a method for operating an elastocaloric heat pump, preferably a previously described elastocaloric heat pump, wherein at least one elastocaloric element is clamped between a first receiving part and a second receiving part of a receiving device, wherein a spring device exerts a spring force on the at least one elastocaloric element, so that the at least one elastocaloric element has a pre-stretching not equal to zero in a force equilibrium of the spring force and a restoring force of the elastocaloric element opposite to the spring force.

[0064] The invention is explained in more detail below with reference to the accompanying figures. They show: Fig. 1 an elastocaloric heat pump with an elastocaloric arrangement, Fig. 2A a stress-strain diagram of an elastocaloric material, Fig. 2B a strain characteristic of an elastocaloric element, Fig. 3 a spring characteristic curve of a spring device, and Fig. 4 a characteristic curve of an elastocaloric arrangement.

[0065] Fig. 1 shows an elastocaloric heat pump 100 in accordance with the invention. The elastocaloric heat pump 100 has an elastocaloric assembly 10 with a receiving device 11. The receiving device 11 comprises a first receiving part 12 and a second receiving part 13, between which a plurality of rod-shaped elastocaloric elements 14 are clamped. The first receiving part 12 and the second receiving part 13 are arranged so as to be movable relative to one another. The elastocaloric assembly 11 further comprises a spring device 15 with a plurality of spring elements 16. The spring elements 16 are preferably designed as gas springs 17 and are arranged between a first spring stop surface 18 of the first receiving part 12 and a second spring stop surface 19 of the second receiving part 13. The spring device exerts spring forces 20 on the elastocaloric elements 14 via the first receiving part 12 and the second receiving part 13 and applies a tensile stress 21 to them.Conversely, the elastocaloric elements 14 subjected to tensile stress exert restoring forces 22, whereby the elastocaloric elements 14 in force equilibrium in the neutral position shown have a pre-strain 23 not equal to zero.

[0066] The elastocaloric heat pump 100 further comprises a first actuator 24 and a second actuator 25, which are designed to cyclically move the first receiving part 12 and the second receiving part 13 towards and away from each other during operation and thereby cyclically deform the elastocaloric elements 14.

[0067] Fig. Figure 2A shows a stress-strain diagram for the elastocaloric material of the elastocaloric elements 14. The stress σ in MPa is plotted against the strain ε in %. Fig. Figure 2B shows the strain characteristic of an elastocaloric element 14 for a cross-sectional area of ​​the elastocaloric element 14 of 10 mm 2The strain characteristic is calculated by multiplying the stress σ by the cross-sectional area. The force in N is plotted against the strain ε in %.

[0068] The elastocaloric element 14 exhibits a hysteresis in an expansion range 26 with a lower limit 27 of 1% and an upper limit 28 of approximately 4.5%. To utilize the calorific effect for the heat pump 100, the elastocaloric elements 14 must be cyclically deformed within the expansion range 26 by the actuators 24, 25. To bring the elastocaloric elements 14 into the expansion range 26, forces of approximately 3,000 to 4,000 N are required. These forces are applied by the spring device 15 of the elastocaloric arrangement 10, so that these forces do not need to be applied and supported by the actuators 24, 25. The pre-stretching 23 of the elastocaloric elements 14 caused by the spring device 15 is selected such that it lies in the force equilibrium in the stretching range 26 between the lower limit 27 and the upper limit 28.

[0069] Fig. Figure 3 shows a spring characteristic curve of the spring device 15. The spring force 20 in N is plotted against the deflection in mm. The spring characteristic curve is degressive, i.e., it is essentially constant at large deflections. The spring device 15 is selected such that the spring characteristic curve is constant and largely independent of deflection in the range from 3,000 to 4,000 N, i.e., in the range of spring forces 20 necessary to bring the elastocaloric elements 14 into the extension range 26.

[0070] The Fig. The characteristic curve of the overall system of the elastocaloric arrangement 10 shown in Figure 4 is then obtained by superimposing the spring characteristic curve according to Fig. 3 with the strain characteristic according to Fig. 2B. The spring device 15 applies a spring force 20 of approximately 4,000 N to the elastocaloric elements 14, so that their pre-stretch 23 lies within the stretch range 26 between the lower limit 27 and the upper limit 28. The forces required by the actuators 24, 25 to offset the hysteresis are in the range of -500 N and +500 N, as can be easily seen from the y-axis. The force of approximately 4,000 N required to bring the elastocaloric elements 14 into the stretch range 26 therefore no longer needs to be applied by the actuators 24, 25, so that they are significantly relieved of mechanical stress.

[0071] In the expansion region 26, the spring characteristic curve of the spring device 15 runs Fig. 3 as well as the strain characteristic of the elastocaloric elements 14 according to Fig. 2B is essentially constant, so that the characteristic curve of the superposition according to Fig.4 is constant in the strain range 26. The forces applied by the actuators 24, 25 are therefore only necessary to overcome the material hysteresis of the elastocaloric elements 14. List of reference symbols 100 Elastocaloric heat pump 10 Elastocaloric arrangement 11 Mounting device 12 First recording part 13 Second recording part 14 Elastocaloric element 15 Spring device 16 spring element 17 Gas spring 18 First spring stop surface 19 Second spring stop surface 20 spring force 21 Tensile stress 22 Restoring force 23 Pre-stretch 24 First Actor 25 Second Actor 26 stretch range 27 Lower limit 28 Upper limit

Claims

[1] Elastocaloric heat pump (100) with an elastocaloric arrangement (10), wherein the elastocaloric arrangement (10) comprises at least one elastocaloric element (14) and a receiving device (11) with a first receiving part (12) and a second receiving part (13) and a spring device (15), wherein the at least one elastocaloric element (14) is clamped between the first receiving part (12) and the second receiving part (13), wherein the spring device (15) is designed to exert a spring force (20) on the at least one elastocaloric element (14), wherein the at least one elastocaloric element (14) has a pre-stretch (23) not equal to zero in a force equilibrium of the spring force (20) and a restoring force (22) of the elastocaloric element (14) opposite to the spring force (20), characterized byin that the at least one elastocaloric element (14) has a predetermined and / or material-dependent elongation range (26) which can be used for an elastocaloric effect and has an upper limit (28) and a lower limit (27), wherein the pre-elongation (23) lies within the elongation range (26), wherein the amount of the lower limit (27) is between 0.5% and 5%, preferably between 0.7% and 2%, more preferably 1%, and / or that the amount of the upper limit (28) is between 2% and 20%, preferably between 3% and 10%, more preferably between 4% and 7.5%, particularly preferably 4.5%. [2] Elastocaloric heat pump (100) according to claim 1, characterized by in that the elastocaloric arrangement (10) comprises a plurality of elastocaloric elements (14), wherein the plurality of elastocaloric elements (14) are clamped between the first receiving part (12) and the second receiving part (13). [3] Elastocaloric heat pump (100) according to claim 1 or 2, characterized by that the spring device (15) is connected to the first receiving part (12) and the second receiving part (13) in such a way that the spring force (20) of the spring device (15) is transmitted via the first receiving part (12) and the second receiving part (13) to the at least one elastocaloric element (14). [4] Elastocaloric heat pump (100) according to one of the preceding claims, characterized bythat the spring force (20) in the force equilibrium corresponds to the restoring force (22) of the elastocaloric element (14) at the lower limit (27) of the expansion range (26) or that the spring force (20) in the force equilibrium corresponds to the restoring force (22) of the elastocaloric element (14) at the upper limit (28) of the expansion range (26) or that the spring force (20) in the force equilibrium corresponds to a value between the restoring force (22) of the elastocaloric element (14) at the lower limit (27) of the expansion range (26) and the restoring force (22) of the elastocaloric element (14) at the upper limit (28) of the expansion range (26), wherein preferably the spring force (20) in the force equilibrium corresponds to an average value of the restoring force (22) of the elastocaloric element (14) at the lower limit (27) of the expansion range (26) and the restoring force (22) of the elastocaloric element (14) at the upper limit (28) of the expansion range (26). [5] Elastocaloric heat pump (100) according to one of the preceding claims, characterized by that the pre-stretching (23) is a positive elongation, in particular a stretching, or that the pre-stretching (23) is a negative elongation, in particular a compression. [6] Elastocaloric heat pump (100) according to one of the preceding claims, characterized by that the spring device (15) comprises a tension spring or a compression spring, wherein preferably the spring device (15) comprises a gas spring (17) and / or a disc spring and / or a hydraulic spring and / or a helical spring and / or an annular spring, and / or wherein the spring device (15) comprises an elastocaloric material. [7] Elastocaloric heat pump (100) according to one of the preceding claims, characterized byin that the spring device (15) has a degressive spring characteristic curve, wherein the spring characteristic curve is preferably substantially constant in the force equilibrium, preferably in the extension range (26), and / or in that the elastocaloric element (14) has a substantially constant extension characteristic curve and / or a substantially constant, preferably linear, extension modulus in the force equilibrium, preferably in the extension range (26), wherein a superposition of the spring characteristic curve and the extension characteristic curve or the extension modulus in the force equilibrium, preferably in the extension range (26), is preferably substantially constant. [8] Elastocaloric heat pump (100) according to one of the preceding claims, characterized by that at least one actuator (24, 25) is provided, wherein the at least one actuator (24, 25) is designed to cyclically stretch the at least one elastocaloric element (14) during operation, preferably within the stretching range (26). [9] Elastocaloric heat pump (100) according to claim 8, characterized by that the at least one actuator (24, 25) is connected to the first receiving part (12) and / or the second receiving part (13). [10] Motor vehicle comprising an elastocaloric heat pump (100) according to one of the preceding claims. [11] Method for operating an elastocaloric heat pump (100) according to one of claims 1 to 9, wherein at least one elastocaloric element (14) is clamped between a first receiving part (12) and a second receiving part (13) of a receiving device (11), wherein a spring device (15) exerts a spring force (20) on the at least one elastocaloric element (14) such that the at least one elastocaloric element (14) has a pre-stretch (23) not equal to zero in a force equilibrium of the spring force (20) and a restoring force (22) of the elastocaloric element (14) opposite to the spring force (20).

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