MAGNETIC HEAT PUMP APPARATUS

• US 20120272665A1
• Filed: 04/23/2012
• Published: 11/01/2012
• Est. Priority Date: 04/26/2011
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Watanabe, Naoki, Nishizawa, Kazutoshi, Yatsuzuka, Shinichi, Morimoto, Tsuyoshi
• Granted Patent: US 9,546,803 B2
• Time in Patent Office: Days
• US Class Current: 62/3.1
• CPC Class Codes: F25B 21/00 Machines, plants or systems, using electric or magnetic effects
• CPC Class Codes: F25B 2321/0022 with a rotating or otherwise moving magnet
• CPC Class Codes: F25B 25/005 using primary and secondary systems
• CPC Class Codes: Y02B 30/00 Energy efficient heating, ventilation or air conditioning [HVAC]

Abstract

A magnetic heat pump cycle has a first to a fourth steps, which are repeatedly carried out. In the first step, a movement of heat medium is stopped by a pressure valve and a pressure accumulating tank and a magnetic field is applied by a magnetic-field control unit to a magnetic working material. In the second step, the pressure valve is opened so that the heat medium flows in a working chamber from a second axial end to a first axial end, and the magnetic field is increased depending on a moving speed of the heat medium. In the third step, the movement of the heat medium is stopped and the magnetic field is decreased. In the fourth step, the heat medium is moved in a revered direction and the magnetic field is decreased depending on the moving speed of the heat medium.

Claims

1. A magnetic heat pump apparatus comprising:

a magnetic refrigerating device including;

a container device having a working chamber for accommodating magnetic working material having magnetocaloric effect, heat medium passing through the working chamber;

a magnetic-field control unit for changing degree of the magnetic field to be applied to the magnetic working material; and

a heat-medium moving device for moving the heat medium in the working chamber so that the heat medium is reciprocated between a first axial end and a second axial end of the working chamber;

a heat radiating device for radiating heat, which is contained in the heat medium on a side of the second axial end, to an outside of the heat radiating device; and

a heat absorbing device for absorbing heat from an outside of the heat absorbing device into the heat medium, which is on a side of the first axial end,

wherein a heat pump cycle of the magnetic heat pump apparatus includes following first to fourth steps, which are repeatedly carried out;

the first step for increasing temperature of the magnetic working material;

the second step for increasing the degree of the magnetic field to be applied to the magnetic working material, temperature of which is increased in the first step, by the magnetic-field control unit, wherein the heat medium is moved from the first axial end to the second axial end by the heat-medium moving device;

the third step for decreasing the temperature of the magnetic working material after the second step; and

the fourth step for decreasing the degree of the magnetic field applied to the magnetic working material, the temperature of which is decreased in the third step, by the magnetic-field control unit, wherein the heat medium is moved from the second axial end to the first axial end by the heat-medium moving device,

wherein heat absorbed in the heat absorbing device is radiated from the heat radiating device, and

wherein the heat-medium moving device and the magnetic-field control unit are synchronized in such a manner that, in the second and fourth steps, a change rate of the degree of the magnetic field to be applied to the magnetic working material by the magnetic-field control unit is made larger, as a moving speed of the heat medium by the heat-medium moving device is higher.

2. The magnetic heat pump apparatus according to claim 1, wherein

the magnetic-field control unit changes a magnetic resistance of a magnetic circuit, in which the magnetic working material is provided, depending on an operational phase of the heat pump cycle, so as to change the degree of the magnetic field to be applied to the magnetic working material and to thereby change the change rate of the degree of the magnetic field in the second and fourth steps.

3. The magnetic heat pump apparatus according to claim 2, wherein

a gap, in which the magnetic working material is arranged, is formed in the magnetic circuit, and

the magnetic-field control unit changes a size of the gap depending on the operational phase so as to change the magnetic resistance of the magnetic circuit.

4. The magnetic heat pump apparatus according to claim 2, wherein

the magnetic-field control unit changes a magnetic resisting value of a magnetic resisting member, which is provided in the magnetic circuit, so as to change the magnetic resistance of the magnetic circuit.

5. The magnetic heat pump apparatus according to claim 2, further comprising;

a yoke for forming a part of the magnetic circuit,

wherein a notched portion, which is different from the gap in which the magnetic working material is arranged, is formed in the yoke,

the magnetic-field control unit changes a space dimension of the notched portion depending on the operational phase, so as to change the magnetic resistance in the magnetic circuit.

6. The magnetic heat pump apparatus according to claim 1, wherein

the magnetic-field control unit has multiple permanent magnets, which move relative to the magnetic working material,

the permanent magnets have different magnetic characteristics from one another in a direction, in which the permanent magnets move relative to the magnetic working material, in such a manner the change rate of the degree of the magnetic field varies depending on the moving speed of the heat medium during the second and fourth steps.

7. The magnetic heat pump apparatus according to claim 6, wherein

the magnetic characteristic includes one of a residual magnetic flux density and a magnetic holding force of the permanent magnets.

8. The magnetic heat pump apparatus according to claim 6, wherein

the magnetic characteristic is a magnetizing direction of the permanent magnets.

9. The magnetic heat pump apparatus according to claim 6, wherein

the magnetic characteristic is a thickness of the permanent magnets, which varies along the direction, in which the permanent magnets move relative to the magnetic working material.

10. The magnetic heat pump apparatus according to claim 1, wherein

the magnetic-field control unit includes an electromagnetic coil, and

current supply to the electromagnetic coil is changed during the second and fourth steps depending on the operational phase of the heat pump cycle, so that the change rate of the degree of the magnetic field varies depending on the moving speed of the heat medium.

11. The magnetic heat pump apparatus according to claim 1, wherein

in the first step, the magnetic field to be applied to the magnetic working material is increased by the magnetic-field control unit, while the movement of the heat medium in the working chamber is stopped by the heat-medium moving device,

the second step is carried out after the elapse of a certain period of time from a start of the first step or when a physical quantity varying in accordance with the passage of time reaches at a predetermined value,

in the third step, the magnetic field applied to the magnetic working material is decreased by the magnetic-field control unit, while the movement of the heat medium in the working chamber is stopped by the heat-medium moving device, and

the fourth step is carried out after the elapse of a certain period of time from a start of the third step or when the physical quantity varying in accordance with the passage of time reaches at another predetermined value.

12. A magnetic heat pump apparatus comprising:

a magnetic refrigerating device including;

a container device having a working chamber for accommodating magnetic working material having magnetocaloric effect, heat medium passing through the working chamber;

a magnetic-field control unit for changing degree of the magnetic field to be applied to the magnetic working material; and

a heat-medium moving device for moving the heat medium in the working chamber so that the heat medium is reciprocated between a first axial end and a second axial end of the working chamber;

a heat radiating device for radiating heat, which is contained in the heat medium on a side of the second axial end, to an outside of the heat radiating device; and

a heat absorbing device for absorbing heat from an outside of the heat absorbing device into the heat medium, which is on a side of the first axial end,

wherein a heat pump cycle of the magnetic heat pump apparatus includes following first to fourth steps, which are repeatedly carried out so that heat absorbed in the heat absorbing device is radiated from the heat radiating device;

the first step for increasing the magnetic field to be applied to the magnetic working material by the magnetic-field control unit, while the movement of the heat medium in the working chamber by the heat-medium moving device is stopped;

the second step for moving the heat medium from the first axial end to the second axial end by the heat-medium moving device without decreasing the magnetic field applied to the magnetic working material, which has been increased by the magnetic-field control unit in the first step, wherein the second step is carried out after the elapse of a certain period of time from a start of the first step or when a physical quantity varying in accordance with the passage of time reaches at a predetermined value;

the third step for decreasing the magnetic field applied to the magnetic working material by the magnetic-field control unit after the second step, while the movement of the heat medium in the working chamber by the heat-medium moving device is stopped; and

the fourth step for moving the heat medium from the second axial end to the first axial end by the heat-medium moving device without increasing the magnetic field applied to the magnetic working material, which has been decreased by the magnetic-field control unit in the third step, wherein the fourth step is carried out after the elapse of a certain period of time from a start of the third step or when the physical quantity varying in accordance with the passage of time reaches at another predetermined value.

13. The magnetic heat pump apparatus according to claim 12, wherein

the heat-medium moving device is continuously operated for reciprocating the heat medium,

a heat-medium-movement prohibiting unit is provided for prohibiting movement of the heat medium in the working chamber, and

the movement of the heat medium in the working chamber is stopped by the heat-medium-movement prohibiting unit in the first and third steps, while the heat-medium moving device is in its operation.

14. The magnetic heat pump apparatus according to claim 13, wherein

the heat-medium moving device is composed of a pump device, which is provided at an outside of the working chamber for continuously changing volume of pump chambers to suck the heat medium from the working chamber or discharge the heat medium into the working chamber so as to reciprocate the heat medium in the working chamber,

the heat-medium-movement prohibiting unit is composed of;

(i) a pressure accumulating device for accumulating a discharging pressure or a sucking pressure; and

(ii) a pressure valve device, which is opened when a pressure difference between the working chamber and the pump chambers reaches at a predetermined pressure so that the heat medium flows into the working chamber in accordance with a discharging or a sucking operation of the pump device together with an accumulated discharging pressure or an accumulated sucking pressure of the pressure accumulating device,

wherein the first step is changed to the second step, when the pressure valve device is opened when the pressure difference reaches at the predetermined pressure, wherein the pressure difference corresponds to the physical quantity which varies in accordance with the passage of time, and

wherein the third step is changed to the fourth step, when the pressure valve device is opened when the pressure difference reaches at the predetermined pressure, wherein the pressure difference corresponds to the physical quantity which varies in accordance with the passage of time.

15. The magnetic heat pump apparatus according to claim 12, wherein

in the second step, the magnetic field to be applied to the magnetic working material is increased by the magnetic-field control unit depending on a moving speed of the heat medium, which is moved by the heat-medium moving device from the first axial end to the second axial end, and

in the fourth step, the magnetic field applied to the magnetic working material is decreased by the magnetic-field control unit depending on a moving speed of the heat medium, which is moved by the heat-medium moving device from the second axial end to the first axial end.

16. The magnetic heat pump apparatus according to claim 15, wherein

in the second step, the magnetic field to be applied to the magnetic working material is more slowly increased by the magnetic-field control unit than the first step, and

in the fourth step, the magnetic field applied to the magnetic working material is more slowly decreased by the magnetic-field control unit than the third step.