MAGNETOCALORIC DEVICE

Abstract

The invention relates to a magnetocaloric device, comprising a field generator, arranged to provide a changing external magnetic field and a magnetocaloric regenerator arrangement. The magnetocaloric regenerator arrangement comprises a magnetocaloric element, wherein the magnetocaloric element comprises magnetocaloric material, and wherein the magnetocaloric regenerator arrangement is arranged to be exposed to the changing external magnetic field of the field generator. Furthermore, the invention is characterized in that the magnetocaloric device further comprises an insulating means wherein the insulating means is arranged such that the magnetocaloric regenerator arrangement is hermetically surrounded by the insulating means.

Claims

1. A magnetocaloric device, comprising: a field generator, arranged to provide a changing external magnetic field, a magnetocaloric regenerator arrangement, comprising a magnetocaloric element, wherein the magnetocaloric element comprises magnetocaloric material, and wherein the magnetocaloric regenerator arrangement is arranged to be exposed to the changing external magnetic field of the field generator, wherein in that the magnetocaloric device further comprises: an insulator, wherein the insulator is arranged such that the magnetocaloric regenerator arrangement is hermetically surrounded by the insulator.

2. The magnetocaloric device according to claim 1, further comprising: a fluid directing system, comprising at least a first and a second channel, arranged to direct a fluid through the first channel to the magnetocaloric regenerator arrangement and to direct the fluid through the second channel away from the magnetocaloric regenerator arrangement, and wherein the insulator further comprise a flow-through for a passing of the fluid through the at least first and second channel.

3. The magnetocaloric device according to claim 1, wherein the insulator is an insulating casing, which is at least partly not in contact with the magnetocaloric regenerator arrangement, and wherein the insulation casing is filled or adapted to be filled with an insulation.

4. The magnetocaloric device according to claim 1, wherein the insulator is an insulating coating, which is completely in contact with the magnetocaloric regenerator arrangement.

5. The magnetocaloric device according to claim 3, wherein the insulation has a lower thermal conductivity than atmospheric air.

6. The magnetocaloric device according to claim 3, wherein the flow-trough is arranged to leave a gap between insulating casing and the at least first and second channel and wherein a sealing member is arranged to seal the gap.

7. The magnetocaloric device according to claim 3, further comprising: a filling valve arranged at the insulating casing and configured to allow a filling of the insulating casing with the insulation.

8. The magnetocaloric device according to claim 3, wherein the insulation is a dry gas.

9. The magnetocaloric device according to claim 8, wherein the dry gas comprises dry air and/or an inert gas, nitrogen, helium, neon, argon, krypton or xenon.

10. The magnetocaloric device according to claim 1, wherein a drying agent is provided in the insulator.

11. The magnetocaloric device according to claim 1, wherein the field generator and the magnetocaloric regenerator arrangement are both located in the insulator.

12. The magnetocaloric device according to claim 11, wherein all further parts of the magnetocaloric device are located in the insulator.

13. The magnetocaloric device according to claim 11, wherein the insulating casing is formed as an evacuable vacuum chamber.

14. The magnetocaloric device according to claim 1, wherein the magnetocaloric device comprises a crankshaft, which is arranged and configured to move the magnetocaloric regenerator arrangement and the field generator with respect to each other during an operation of the magnetocaloric device, and wherein the insulator allows an access to the crankshaft from an outer side of the insulating means.

15. The magnetocaloric device according to claim 14, wherein the crankshaft is arranged to leave a shaft gap between insulating casing and the crankshaft and wherein a shaft sealing member is arranged to seal the shaft gap.

16. The magnetocaloric device according to claim 1, further comprising: a support structure, which is arranged to support the field generator and the magnetocaloric regenerator arrangement, and wherein the insulator allows an access to the support structure from the outer side of the insulator to allow an attaching of the magnetocaloric device to an external object.

17. The magnetocaloric device according to claim, wherein the magnetocaloric device comprises at least one further magnetocaloric regenerator arrangement comprising a further magnetocaloric element, wherein the magnetocaloric element comprises magnetocaloric material, and wherein the further magnetocaloric regenerator arrangement is arranged to be exposed to the changing external magnetic field, and wherein a further insulator is provided such that the further magnetocaloric regenerator arrangement is located in the further insulator.

Description

[0040] In the following, the drawing shows in:

[0041] FIG. 1 a first embodiment of a magnetocaloric device according to the invention, wherein an insulating casing is located in a magnetic gap of a field generator;

[0042] FIG. 2 a second embodiment of the magnetocaloric device according to the invention, wherein the field generator and a magnetocaloric regenerator arrangement are located in the insulating casing, while a motor of the magnetocaloric device is located outside of the insulating casing;

[0043] FIG. 3 a third embodiment of the magnetocaloric device according to the invention, wherein the field generator the magnetocaloric regenerator arrangement and the motor of the magnetocaloric device are located in the insulating casing.

[0044] FIG. 1 shows a first embodiment of a magnetocaloric device 100 according to the invention, wherein an insulating means 105 formed by an insulating casing 110 is located in a magnetic gap 125 of a field generator 120.

[0045] The magnetocaloric device 100 of this first embodiment is a magnetocaloric heat pump, which comprises the field generator 120, comprising the magnetic gap 125 between a first magnet assembly 126 and a second magnet assembly 128, and a magnetocaloric regenerator arrangement 130, arranged in the magnetic gap 125. The magnetocaloric regenerator arrangement 130 comprises a plurality of magnetocaloric elements 132, wherein each of the magnetocaloric elements 132 comprises magnetocaloric material 135, and wherein the magnetocaloric regenerator arrangement 130 is arranged to be exposed to a periodically changing external magnetic field 122, which is provided by the field generator 120.

[0046] The magnetocaloric device 100 further comprises a fluid directing system 140, comprising a first 141, a second 142, a third 143 and a fourth 144 channel, arranged to direct a cold fluid through the first channel 141 to the magnetocaloric regenerator arrangement 130 and to direct the cold fluid through the second channel 142 away from the magnetocaloric regenerator arrangement 130, and to direct a hot fluid through the third channel 143 to the magnetocaloric regenerator arrangement 130 and to direct the hot fluid through the fourth channel 144 away from the magnetocaloric regenerator arrangement 130. The fluid is thereby directed according to magnetization and demagnetization phases of a process cycle of the magnetcaloric heat pump 100, wherein the process cycle is well known by prior art. The cold fluid, which is directed through the second channel 142 away from the magnetocaloric regenerator arrangement 130 is directed to a first heat exchanger 146 before it is again directed through the first channel 141 to the magnetocaloric regenerator arrangement 130. The hot fluid, which is directed through the fourth channel 144 away from the magnetocaloric regenerator arrangement 130 is directed via a pump 147 to a second heat exchanger 148 before it is again directed through the third channel 143 to the magnetocaloric regenerator arrangement 130.

[0047] According to the invention, the magnetocaloric device 100 further comprises the insulating casing 110, wherein the magnetocaloric regenerator arrangement 130 is located in the insulating casing 110 and the insulating casing 110 is arranged such that the magnetocaloric regenerator arrangement 130 is hermetically surrounded by the insulating casing 110 with a flow-through 150 for a passing of the fluid through the first 141, second 142, third 143 and fourth 144 channel. The flow-trough 150 is arranged to leave a gap between insulating casing 110 and the channels 141, 142, 143, 144 and a flow sealing member 155 is arranged to seal the gap. Furthermore, the insulating casing 110 is filled with an insulation 160 that has a lower thermal conductivity than atmospheric air.

[0048] In the depicted embodiment, the insulation 160 is dry air and a drying agent 165 is additionally provided in a carrier 168 that is arranged within the insulating casing 110. The drying agent 165 additionally reduces a humidity of the dry air, in order to reduce the thermal conductivity of the insulation 160. In an embodiment not shown, the insulating casing is formed as an evacuable vacuum chamber.

[0049] The insulating casing 110 is arranged in the magnetic gap 125 of the field generator 120. A motor 170 of the magnetocaloric device 100 is connected to a power supply (not shown) via electrical connectors 175 and is arranged to rotate the first and second magnet assembly 126, 128 of the field generator 120 during an operation of the magnetocaloric device by rotating a crankshaft 180 that is attached to the first and second magnet assembly 126, 128. The insulating casing 110 allows an access to the crankshaft 180 from an outer side of the insulating casing 110. The access is provided by a first and a second opening 182, 184 of the insulating casing 130, wherein the first and second opening 182, 184 is arranged to leave a shaft gap between insulating casing 110 and the crankshaft 180 and wherein a respective shaft sealing member 185 is arranged to seal the respective shaft gap. The shaft sealing member 185 is formed as a rotational seal allowing a rotation of the crankshaft 180 while sealing the shaft gap to the insulating casing 110. In an embodiment not shown, the sealing member is formed as a sealing bearing.

[0050] In further preferred embodiments, any kind of insulation means is arranged in the magnetic gap instead of an insulating casing. In particular, an insulating coating is provided in a preferred embodiment not shown, wherein the insulating coating is completely in contact with the magnetocaloric regenerator arrangement. The insulating coating can be for instance a foam, a varnish, a paint or a foil.

[0051] In a further embodiment not shown, the crankshaft is arranged to rotate the magnetocaloric regenerator arrangement while the field generator is fixed. The channels of the fluid directing system of this further embodiment are arranged in the crankshaft and connected to the magnetocaloric regenerator arrangement via rotary valves.

[0052] The insulating casing 110 further comprises a filling valve 188 arranged at the insulating casing 110 and configured to allow a filling of the insulating casing 110 with the insulation 160. The filling valve 188 is further configured to allow an emptying of the insulating casing 110, in particular an emptying into an appropriate insulation storage box.

[0053] The magnetocaloric device 100 according to the embodiment shown in FIG. 1 further comprises a support structure 190, which is arranged to support the field generator 120 and the magnetocaloric regenerator arrangement 130, and wherein the insulating casing 110 allows an access to the support structure 190 from the outer side of the insulating casing 110 to allow an attaching of the magnetocaloric device 100 to an external object 195.

[0054] In an embodiment not shown, the magnetocaloric device comprises at least one further magnetocaloric regenerator arrangement comprising a further plurality of magnetocaloric elements, wherein each of the magnetocaloric elements comprises magnetocaloric material, and wherein the further magnetocaloric regenerator arrangement is arranged to be exposed to the periodically changing external magnetic field, and wherein a further insulating casing is provided such that the further magnetocaloric regenerator arrangement is located in the insulating casing. In this embodiment, the magnetocaloric regenerator arrangement and the further magnetocaloric regenerator arrangement are both arranged in the magnetic gap of the field generator. In a further embodiment not shown, the magnetocaloric device is provided such that the first magnetic assembly, the magnetocaloric regenerator arrangement, the second magnetic assembly, the further magnetocaloric regenerator arrangement and a third magnetic assembly are arranged in this order along the crankshaft. In an alternative embodiment not shown, an insulating casing is provided such that the magnetocaloric regenerator and the further magnetocaloric regenerator are located in the insulating casing.

[0055] FIG. 2 shows a second embodiment of the magnetocaloric device 200 according to the invention, wherein the field generator 120 and the magnetocaloric regenerator arrangement 130 are located in the insulating casing 210, while the motor 170 of the magnetocaloric device 200 is located outside of the insulating casing 210.

[0056] The magnetocaloric device 200 is arranged as the magnetocaloric device 100 shown in FIG. 1, the only difference is that in addition to the magnetocaloric regenerator arrangement 130, the field generator 120 is also located in the insulating 210 casing. As a consequence, the first and second opening 182, 184 of the insulating casing 210, which forms the insulating means 205 are not provided in the magnetic gap 125, but between field generator 120 and motor 170, and between field generator 120 and a bearing 220 of the crankshaft 180.

[0057] For embodiments, wherein the magnetocaloric regenerator arrangement and the field generator are located inside the insulating means, the use of an insulating casing as insulating means, as shown in FIG. 2, is preferred. However, using an insulating coating, such as a foam, is also possible and within the scope of the present invention. The insulating casing is filled with atmospheric air in further variants of the embodiment shown in FIG. 2.

[0058] The support structure 190 is arranged as shown in FIG. 1 to support the field generator 120 and the magnetocaloric regenerator arrangement 130, but not illustrated in FIG. 2 for reasons of clarity.

[0059] FIG. 3 shows a third embodiment of the magnetocaloric device 300 according to the invention, wherein the field generator 120 the magnetocaloric regenerator arrangement 130 and the motor 170 of the magnetocaloric device 300 are located in the insulating casing 310, which forms the insulating means 305.

[0060] In contrast to the magnetocaloric device 100 shown in FIG. 1, the field generator 120 and the motor 170 are also located in the insulating casing 310. Furthermore, the crankshaft 180 is completely located in the insulating casing 310 so that there is not a first and a second opening 182, 184, but a bearing 320 of the crankshaft 180 within the insulating casing 310. This bearing may or may not be connected to or supported by the insulating casing. To enable an electrical connection, a connection opening 330 is provided in the insulating casing 310 for the electrical connectors 175. Thereby the electrical connectors enable an electrical power supply of the motor 170 from outside of the insulating casing 310. The opening 330 comprises a connector gap between the electrical connectors 175 and the insulating casing 310, wherein a connector sealing member is arranged to seal the gap.

[0061] Furthermore, the support structure 340 is arranged in the insulating casing 310 in contrast to the support structure 190, illustrated in FIG. 1. Alternatively, the support structure and the insulating casing may be one component serving both functions or they may be attached or integrated into each other. Therefore, the insulating casing 310 forms an outer surface of the magnetocaloric device 300 and can be attached to the external object 195, in order to provide the magnetocaloric device 300 in a fixed position.

[0062] In an embodiment not shown, the motor is further insulated by an additional insulating casing, which guides heat from the motor to an outside of the insulating casing, preferably with cooling fins that connect the additional insulating casing with the insulating casing. Thus, the device of this embodiment advantageously reduces a heat production inside the insulating casing, compared to the embodiment shown in FIG. 3.

List of Reference Signs:

[0063] 100 magnetocaloric device

[0064] 105 insulating means

[0065] 110 insulating casing

[0066] 120 field generator

[0067] 122 external magnetic field

[0068] 125 magnetic gap

[0069] 126 first magnet assembly

[0070] 128 second magnet assembly

[0071] 130 magnetocaloric regenerator arrangement

[0072] 132 magnetocaloric element

[0073] 135 magnetocaloric material

[0074] 140 fluid directing system

[0075] 141 first channel

[0076] 142 second channel

[0077] 143 third channel

[0078] 144 fourth channel

[0079] 146 first heat exchanger

[0080] 147 pump

[0081] 148 second heat exchanger

[0082] 150 flow-trough

[0083] 155 flow sealing member

[0084] 160 insulation

[0085] 165 drying agent

[0086] 168 carrier

[0087] 170 motor

[0088] 175 electrical connector

[0089] 180 crankshaft

[0090] 182 first opening

[0091] 184 second opening

[0092] 185 shaft sealing member

[0093] 188 filling valve

[0094] 190 support structure

[0095] 195 external object

[0096] 200 second embodiment of the magnetocaloric device

[0097] 205 insulating means of the second embodiment

[0098] 210 insulating casing of the second embodiment

[0099] 220 bearing of the crankshaft

[0100] 300 third embodiment of the magnetocaloric device

[0101] 305 insulating means of the third embodiment

[0102] 310 insulating casing of the third embodiment

[0103] 320 bearing of the crankshaft of the third embodiment

[0104] 330 connection opening

[0105] 340 support structure of the third embodiment