Magnetic Heat Pump Device

Abstract

A magnetic heat pump device (1) is provided with a magnetic working substance (13) having a magnetocaloric effect, magnetic working bodies (11A, 11B) in which a heat transfer medium is circulated, permanent magnets (6) changing the size of a magnetic field to be applied to the magnetic working substance, and a displacer (8) causing the heat transfer medium to reciprocate between a high-temperature end (14) and a low-temperature end (16) of the magnetic working body. The displacer (8) moves the heat transfer medium to the high-temperature end side from the low-temperature end side of the magnetic working body before the permanent magnets (6) increase the size of the magnetic field to be applied to the magnetic working substance. An improvement of efficiency is achieved by improving the timing of changing the size of the magnetic field to be applied to the magnetic working substance and the reciprocating movement of the heat transfer medium.

Description

TECHNICAL FIELD

The present invention relates to a magnetic heat pump device utilizing the magnetocaloric effect of magnetic working substances.

BACKGROUND ART

A magnetic heat pump device utilizing a property that magnetic working substances causes a large temperature change in magnetization and demagnetization (magnetocaloric effect) has drawn attention in recent years in place of a conventional vapor compression refrigerating device using a gas refrigerant, such as chlorofluorocarbon.

Heretofore, the magnetic heat pump device of this type changes a magnetic field to be applied to magnetic working substances by charging the magnetic working substances into a duct of a magnetic working body, and then attaching/detaching a permanent magnet to the magnetic working body. At this time, when the magnetic field to be applied is increased (magnetized), the temperature of the magnetic working substances increases, and, when the magnetic field is reduced (demagnetized), the temperature decreases.

Meanwhile, a heat transfer medium (water or the like) is reciprocated between a high-temperature end and a low-temperature end of the magnetic working body using a heat transfer medium moving device containing a displacer (piston), a pump, a rotary valve, and the like. In this case, the magnetic working substances are magnetized to increase the temperature thereof, and then the heat transfer medium is moved to the high-temperature end side from the low-temperature end side, whereby heat is exchanged between the magnetic working substances in which the temperature has increased by the magnetization and the low-temperature heat transfer medium. Thus, a temperature gradient in which the temperature is high on the high-temperature end side and the temperature is low on the low-temperature end side arises in the magnetic working body.

Next, when the magnetic working substances are demagnetized, the temperature decreases. The heat transfer medium is moved to the low-temperature end side from the high-temperature end side, whereby heat is exchanged between the magnetic working substances in which the temperature has decreased by the demagnetization and the high-temperature heat transfer medium. This further increases the temperature gradient of the magnetic working body.

Thus, the temperature change caused by the magnetocaloric effect is stored in the magnetic working body itself and is efficiently taken out to the outside by the heat media on the low-temperature end side and the high-temperature end side, whereby heat absorption (refrigerating) or heat dissipation (heating) is performed with an external heat exchanger (for example, see Patent Document 1).

CITATION LIST

Patent Documents

Patent Document 1: Japanese Patent Application Laid-Open No. 2008-51409

SUMMARY OF THE INVENTION

Problems to be Solved by the Invention

However, the heat transfer medium has been moved to the high-temperature end side from the low-temperature end side simultaneously with the magnetization of the magnetic working substances and has been moved to the low-temperature end side from the high-temperature end side simultaneously with the demagnetization heretofore, and therefore the heat transfer medium (water) has flowed out before sufficient heat exchange has been performed, so that the heat exchange between the magnetic working substances and the heat transfer medium has become insufficient. Thus the temperature change caused by the magnetocaloric effect of the magnetic working substances has not been able to be effectively utilized.

The present invention has been accomplished in order to solve the conventional technical problem. It is an object of the present invention to provide a heat pump device in which an improvement of the efficiency has been achieved by improving the timing of the change of the size of magnetic fields to be applied to magnetic working substances and the reciprocating movement of a heat transfer medium.

Means for Solving the Problems

A magnetic heat pump device of the invention of Claim 1 is provided with a magnetic working body which has a magnetic working substance having a magnetocaloric effect and in which a heat transfer medium is circulated, a magnetic field changing device changing the size of a magnetic field to be applied to the magnetic working substance, a heat transfer medium moving device causing the heat transfer medium to reciprocate between a high-temperature end and a low-temperature end of the magnetic working body, a heat exchanger on a heat dissipation side for causing the heat transfer medium on the high-temperature end side to perform heat dissipation, and a heat exchanger on a heat absorption side for causing the heat transfer medium on the low-temperature end side to perform heat absorption, in which the heat transfer medium moving device moves the heat transfer medium to the high-temperature end side from the low-temperature end side of the magnetic working body before the magnetic field changing device increases the size of the magnetic field to be applied to the magnetic working substance.

A magnetic heat pump device of the invention of Claim 2 is provided with a magnetic working body which has a magnetic working substance having a magnetocaloric effect and in which a heat transfer medium is circulated, a magnetic field changing device changing the size of a magnetic field to be applied to the magnetic working substance, a heat transfer medium moving device causing the heat transfer medium to reciprocate between a high-temperature end and a low-temperature end of the magnetic working body, a heat exchanger on a heat dissipation side for causing the heat transfer medium on the high-temperature end side to perform heat dissipation, and a heat exchanger on a heat absorption side for causing the heat transfer medium on the low-temperature end side to perform heat absorption, in which the heat transfer medium moving device moves the heat transfer medium to the low-temperature end side from the high-temperature end side of the magnetic working body after the magnetic field changing device reduces the size of the magnetic field to be applied to the magnetic working substance.

A magnetic heat pump device of the invention of Claim 3 is provided with a magnetic working body which has a magnetic working substance having a magnetocaloric effect and in which a heat transfer medium is circulated, a magnetic field changing device changing the size of a magnetic field to be applied to the magnetic working substance, a heat transfer medium moving device causing the heat transfer medium to reciprocate between a high-temperature end and a low-temperature end of the magnetic working body, a heat exchanger on a heat dissipation side for causing the heat transfer medium on the high-temperature end side to perform heat dissipation, and a heat exchanger on a heat absorption side for causing the heat transfer medium on the low-temperature end side to perform heat absorption, in which the heat transfer medium moving device moves the heat transfer medium to the high-temperature end side from the low-temperature end side of the magnetic working body before the magnetic field changing device increases the size of the magnetic field to be applied to the magnetic working substance and the heat transfer medium moving device moves the heat transfer medium to the low-temperature end side from the high-temperature end side of the magnetic working body after the magnetic field changing device reduces the size of the magnetic field to be applied to the magnetic working substance.

In a magnetic heat pump device of the invention of Claim 4, when time while the magnetic field changing device is increasing the size of the magnetic field to be applied to the magnetic working substance in the invention of Claim 1 or 3 is defined as T1, the heat transfer medium moving device moves the heat transfer medium to the high-temperature end side from the low-temperature end side of the magnetic working body before time larger than 0 and equal to or smaller than 0.15×T1 before the magnetic field changing device starts to increase the size of the magnetic field to be applied to the magnetic working substance.

In a magnetic heat pump device of the invention of Claim 5, when time while the magnetic field changing device is reducing the size of the magnetic field to be applied to the magnetic working substance in the invention of Claim 2 or 3 is defined as T2, the heat transfer medium moving device moves the heat transfer medium to the low-temperature end side from the high-temperature end side of the magnetic working body after time equal to or larger than 0.25×T2 and equal to or smaller than 0.33×T2 after the magnetic field changing device reduced the size of the magnetic field to be applied to the magnetic working substance.

In a magnetic heat pump device of the invention of Claim 6, when time while the magnetic field changing device is increasing the size of the magnetic field to be applied to the magnetic working substance in the invention of Claim 3 is defined as T1, the heat transfer medium moving device moves the heat transfer medium to the high-temperature end side from the low-temperature end side of the magnetic working body before time larger than 0 and equal to or smaller than 0.15×T1 before the magnetic field changing device starts to increase the size of the magnetic field to be applied to the magnetic working substance, and when time while the magnetic field changing device is reducing the size of the magnetic field to be applied to the magnetic working substance is defined as T2, the heat transfer medium moving device moves the heat transfer medium to the low-temperature end side from the high-temperature end side of the magnetic working body after time equal to or larger than 0.25×T2 and equal to or smaller than 0.33×T2 after the magnetic field changing device reduced the size of the magnetic field to be applied to the magnetic working substance.

Advantageous Effect of the Invention

According to the invention of Claim 1 or 3, in the magnetic heat pump device provided with the magnetic working body which has the magnetic working substance having the magnetocaloric effect and in which the heat transfer medium is circulated, the magnetic field changing device changing the size of the magnetic field to be applied to the magnetic working substance, the heat transfer medium moving device causing the heat transfer medium to reciprocate between the high-temperature end and the low-temperature end of the magnetic working body, the heat exchanger on the heat dissipation side for causing the heat transfer medium on the high-temperature end side to perform heat dissipation, and the heat exchanger on the heat absorption side for causing the heat transfer medium on the low-temperature end side to perform heat absorption, the heat transfer medium moving device moves the heat transfer medium to the high-temperature end side from the low-temperature end side of the magnetic working body before the magnetic field changing device increases the size of the magnetic field to be applied to the magnetic working substance. Therefore, a low-temperature heat transfer medium can be sent into the magnetic working substance before the size of the magnetic field to be applied to the magnetic working substance is increased, so that a temperature difference from the magnetic working substance in which the temperature has increased by the subsequent magnetic field increase can be increased.

Thus, heat can be efficiently exchanged between the magnetic working substance and the heat transfer medium, the temperature gradient between the high-temperature end and the low-temperature end of the magnetic working body can be increased, and the temperature change caused by the magnetocaloric effect of the magnetic working substance can be effectively and efficiently utilized.

In this case, when the time while the magnetic field changing device is increasing the size of the magnetic field to be applied to the magnetic working substance is defined as T1, the heat transfer medium moving device moves the heat transfer medium to the high-temperature end side from the low-temperature end side of the magnetic working body before time larger than 0 and equal to or smaller than 0.15×T1 before the magnetic field changing device starts to increase the size of the magnetic field to be applied to the magnetic working substance as with the invention of Claim 4 or 6, whereby the temperature increase of the magnetic working substance can be effectively utilized.

According to the invention of Claim 2 or 3, in the magnetic heat pump device provided with the magnetic working body which has the magnetic working substance having the magnetocaloric effect and in which the heat transfer medium is circulated, the magnetic field changing device changing the size of the magnetic field to be applied to the magnetic working substance, the heat transfer medium moving device causing the heat transfer medium to reciprocate between the high-temperature end and the low-temperature end of the magnetic working body, the heat exchanger on the heat dissipation side for causing the heat transfer medium on the high-temperature end side to perform heat dissipation, and the heat exchanger on the heat absorption side for causing the heat transfer medium on the low-temperature end side to perform heat absorption, the heat transfer medium moving device moves the heat transfer medium to the low-temperature end side from the high-temperature end side of the magnetic working body after the magnetic field changing device reduces the size of the magnetic field to be applied to the magnetic working substance. Therefore, the heat transfer medium can be moved after the size of the magnetic field to be applied to the magnetic working substance is reduced, so that the temperature of the heat transfer medium can be further reduced by the magnetic working substance in which the temperature has decreased by the reduction in the magnetic field.

Thus, the temperature reduction of the magnetic working substance can be effectively utilized, the temperature gradient between the high-temperature end and the low-temperature end of the magnetic working body can be increased, and the temperature change caused by the magnetocaloric effect of the magnetic working substance can be effectively and efficiently utilized.

In this case, when the time while the magnetic field changing device is reducing the size of the magnetic field to be applied to the magnetic working substance is defined as T2, the heat transfer medium moving device moves the heat transfer medium to the low-temperature end side from the high-temperature end side of the magnetic working body after time equal to or larger than 0.25×T2 and equal to or smaller than 0.33×T2 after the magnetic field changing device reduced the size of the magnetic field to be applied to the magnetic working substance as with the invention of Claim 5 or 6, whereby the temperature reduction of the magnetic working substance can be effectively utilized.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an entire block diagram of a magnetic heat pump device of an example to which the present invention is applied.

FIG. 2 is a cross-sectional view of an AMR (Active Magnetic Regenator) for the magnetic heat pump of FIG. 1.

FIG. 3 is a cross-sectional view of a magnetic working body explaining an operation of moving a heat transfer medium before magnetizing magnetic working substances.

FIG. 4 is a cross-sectional view of the magnetic working body in a state where the magnetic working substances are magnetized.

FIG. 5 is a cross-sectional view of the magnetic working body when the magnetic working substances are demagnetized.

FIG. 6 is a cross-sectional view of the magnetic working body explaining an operation of moving the heat transfer medium after the magnetic working substances are demagnetized.

MODE FOR CARRYING OUT THE INVENTION

Hereinafter, one embodiment of the present invention is described based on the drawings. FIG. 1 illustrates an entire block diagram of a magnetic heat pump device 1 of an example to which the present invention is applied. FIG. 2 illustrates a cross-sectional view of a magnetic heat pump AMR 2 of the magnetic heat pump device 1.

(1) Configuration of Magnetic Heat Pump Device 1

First, the magnetic heat pump AMR 2 of FIG. 2 is described. The magnetic heat pump AMR 2 of the magnetic heat pump device 1 is provided with a hollow cylindrical housing 3 both ends in the axial direction of which are closed and a rotating body 7 which is located in the axial center in the housing 3 and in which a pair (two pieces) of permanent magnets 6 (magnetic field generating member) are radially attached to axisymmetric peripheral surfaces. Both ends of a shaft of the rotating body 7 are rotatably and pivotally supported by the housing 3 and the rotating body 7 is coupled to a rotating shaft 10 of a motor M (FIG. 1, servo motor) through a decelerator which is not illustrated and the rotation is controlled by the motor M. The rotating body 7, the permanent magnets 6, the motor M, and the like configure a magnetic field changing device changing the size of a magnetic field to be applied to magnetic working substances 13 described later. Moreover, a cam 9 (FIG. 1) driving a displacer (piston) 8 described later is also coupled to the rotating shaft 10 of the motor M.

Meanwhile, four magnetic working bodies 11A, 11A, 11B, and 11B which are twice the number of the permanent magnets 6 are fixed to the inner periphery of the housing 3 at equal intervals in the circumferential direction in a state of approaching the outer peripheral surface of the permanent magnets 6. In the case of the example, the magnetic working bodies 11A and 11A are disposed at axisymmetric positions with the rotating body 7 interposed therebetween and the magnetic working bodies 11B and 11B are disposed at axisymmetric positions with the rotating body 7 interposed therebetween (FIG. 2). The magnetic working bodies 11A and 11B are those in which magnetic working substances 13 having a magnetocaloric effect are individually charged into a hollow duct 12 having a circular arc shaped cross section along the inner periphery of the housing 3 such that a heat transfer medium (herein water) can circulate (FIG. 1).

Although the magnetic working bodies 11A and 11B are actually disposed in two pairs at the axisymmetric positions as illustrated in FIG. 2, FIG. 1 representatively illustrates one magnetic working body 11A and one magnetic working body 11B. In the example, the duct 12 is configured by a resin material having a high heat insulation property. Thus, the heat loss to the atmosphere (outside) from the magnetic working substances 13 in which the temperature increases or decreases due to the change (magnetization and demagnetization) of the magnetic field as described later is reduced. In the example, an Mn-based material or an La-based material is used as the magnetic working substances 13.

In the entire block diagram of the magnetic heat pump device 1 of FIG. 1 in which the magnetic heat pump AMR 2 is installed, each of the magnetic working bodies 11A and 11B has a high-temperature end 14 at one end (right end in FIG. 1) and has a low-temperature end 16 at the other end (left end in FIG. 1). A high-temperature pipe 17 is connected to the high-temperature end 14 of each of the magnetic working bodies 11A, 11A, 11B, and 11B (FIG. 1 representatively illustrates one magnetic working body 11A and one magnetic working body 11B) and is drawn out from the housing 3 of FIG. 2. Moreover, a low-temperature pipe 18 is connected to the low-temperature end 16 of each of the magnetic working bodies 11A, 11A, 11B, and 11B (FIG. 1 representatively illustrates one magnetic working body 11A and one magnetic working body 11B) and is drawn out from the housing 3 of FIG. 2.

A heat exchanger 19 on the heat dissipation side is connected to the high-temperature pipe 17 and a circulating pump 21 is further placed in the high-temperature pipe 17. A heat exchanger 22 on the heat absorption side is connected to the low-temperature pipe 18 and a circulating pump 23 is further placed also in the low-temperature pipe 18.

The displacers (piston) 8 are individually disposed at the high-temperature end 14 and the low-temperature end 16 of each of the magnetic working bodies 11A, 11A, 11B, and 11B and are driven by the cams 9 rotated by the rotating shaft 10 of the motor M to cause the heat transfer medium (water) to reciprocate between the high-temperature end 14 and the low-temperature end 16 of each of the magnetic working bodies 11A, 11A, 11B, and 11B.

More specifically, when the displacer 8 on the high-temperature end 14 side of each of the magnetic working bodies 11A and 11A retreats and the displacer 8 on the low-temperature end 16 side thereof advances as illustrated in FIG. 1, the heat transfer medium is moved to the high-temperature end 14 side from the low-temperature end 16 side of the magnetic working body 11A. On the other hand, the displacer 8 on the low-temperature end 16 side of each of the magnetic working bodies 11B and 11B retreats and the displacer 8 on the high-temperature end 14 side thereof advances as illustrated in FIG. 1, so that the heat transfer medium is moved to the low-temperature end 16 side from the high-temperature end 14 side of the magnetic working body 11B. The displacers 8 and the cams 9 and further the motor M, the rotating shaft 10, and the like configure a heat transfer medium moving device causing the heat transfer medium to reciprocate between the high-temperature end 14 and the low-temperature end 16 of each of the magnetic working bodies 11A, 11A, 11B, and 11B.

(2) Basic Operation of Magnetic Heat Pump Device 1

The basic operation of the magnetic heat pump device 1 of the above-described configuration is described. First, when the rotating body 7 is located at the position of 0° (position illustrated in FIG. 2), the permanent magnets 6 and 6 are located at the positions of 0° and 180°. Therefore, the size of magnetic fields to be applied to the magnetic working substances 13 of the magnetic working bodies 11A and 11A at the positions of 0° and 180° increases and the temperature increases by magnetization. On the other hand, the size of magnetic fields to be applied to the magnetic working substances 13 of the magnetic working bodies 11B and 11B located at the positions of 90° and 270° having phases different therefrom by 90° decreases and the temperature decreases by demagnetization.

When the rotating body 7 is located at the position of 0° (FIG. 2) by the rotation of the motor M, the cams 9 and 9 are driven by the rotating shaft 10 of the motor M to retreat the displacers 8 on the high-temperature end 14 sides of the magnetic working bodies 11A and 11A and advance the displacers 8 on the low-temperature end 16 sides thereof as illustrated in FIG. 1. Thus, the heat transfer medium is moved to the high-temperature end 14 side from the low-temperature end 16 side of the magnetic working body 11A.

Thus, heat is exchanged between the magnetic working substances 13 of the magnetic working bodies 11A and 11A in which the temperature has increased by magnetization by the permanent magnets 6 and 6 and the low-temperature heat media to thereby produce a temperature gradient in which the temperature on the high-temperature end 14 side is high and the temperature on the low-temperature end 16 side is low in each of the magnetic working bodies 11A and 11A.

When the rotating body 7 is located at the position of 0° (FIG. 2) by the rotation of the motor M, the cams 9 and 9 are driven by the rotating shaft 10 of the motor M to advance the displacers 8 on the high-temperature end 14 sides of the magnetic working bodies 11B and 11B and retreat the displacers 8 on the low-temperature end 16 sides thereof as illustrated in FIG. 1. Thus, the heat transfer medium is moved to the low-temperature end 16 side from the high-temperature end 14 side of the magnetic working body 11A. Thus, heat is exchanged between the magnetic working substances 13 of the magnetic working bodies 11B and 11B in which the temperature has decreased by demagnetization and the high-temperature heat media to further increase the temperature gradients of the magnetic working bodies 11B and 11B.

Next, when the rotating body 7 is rotated by 90° by the motor M, the permanent magnets 6 and 6 are brought to the positions of 90° and 270°. Therefore, the size of magnetic fields to be applied to the magnetic working substances 13 of the magnetic working bodies 11B and 11B located at the positions of 90° and 270° increases and the temperature increases by magnetization. On the other hand, the size of magnetic fields to be applied to the magnetic working substances 13 of the magnetic working bodies 11A and 11A located at the positions of 0° and 180° having phases different therefrom by 90° decreases and the temperature decreases by demagnetization.

When the rotating body 7 is located at the position of 90° by the rotation of the motor M, the cams 9 and 9 are driven by the rotating shaft 10 of the motor M to advance the displacers 8 on the high-temperature end 14 sides of the magnetic working bodies 11A and 11A and retreat the displacers 8 on the low-temperature end 16 sides thereof. Thus, the heat transfer medium is moved to the low-temperature end 16 side from the high-temperature end 14 side of the magnetic working body 11A. Thus, heat is exchanged between the magnetic working substances 13 of the magnetic working bodies 11A and 11A in which the temperature has decreased by demagnetization and the high-temperature heat media to further increase the temperature gradients of the magnetic working bodies 11A and 11A.

When the rotating body 7 is brought to the position of 90° by the rotation of the motor M, the cams 9 and 9 are driven by the rotating shaft 10 of the motor M to advance the displacers 8 on the low-temperature end 16 sides of the magnetic working bodies 11B and 11B and retreat the displacers 8 on the high-temperature end 14 sides thereof. Thus, the heat transfer medium is moved to the high-temperature end 14 side from the low-temperature end 16 side of the magnetic working body 11B.

Thus, heat is exchanged between the magnetic working substances 13 of the magnetic working bodies 11B and 11B in which the temperature has increased by magnetization by the permanent magnets 6 and 6 and the low-temperature heat media to further increase the temperature gradients of the magnetic working bodies 11B and 11B.

Thus, the heat transfer medium on the high-temperature end 14 side of each of the magnetic working bodies 11A, 11A, 11B, and 11B in which the temperature has increased is circulated in the heat exchanger 19 on the heat dissipation side through the high-temperature pipe 17 by the circulating pump 21. The heat transfer medium on the low-temperature end 16 side of each of the magnetic working bodies 11A, 11A, 11B, and 11B in which the temperature has decreased is circulated in the heat exchanger 22 on the heat absorption side through the low-temperature pipe 18 by the circulating pump 23.

The rotation of the rotating body 7 by the motor M and the switching of the displacers 8 are performed at relatively high-speed number of rotation and timing, the heat transfer medium (water) is reciprocated between the high-temperature end 14 and the low-temperature end 16 of each of the magnetic working bodies 11A, 11A, 11B, and 11B, and heat absorption/heat dissipation from the magnetic working substances 13 of each of the magnetic working bodies 11A, 11A, 11B, and 11B to be magnetized/demagnetized is repeated, whereby a temperature difference between the high-temperature end 14 and the low-temperature end 16 of each of the magnetic working bodies 11A, 11A, 11B, and 11B gradually increases. Then, the temperature of the low-temperature end 16 of each of the magnetic working bodies 11A, 11A, 11B, and 11B connected to the heat exchanger 22 on the heat absorption side decreases to a temperature at which the refrigerating capacity of the magnetic working substances 13 and a heat load of a cooling target body to be cooled by the heat exchanger 22 are balanced, and then the heat dissipation capability and the refrigerating capacity of the heat exchanger 19 are balanced so that the temperature of the high-temperature end 14 of each of the magnetic working bodies 11A, 11A, 11B, and 11B connected to the heat exchanger 19 on the heat dissipation side becomes a substantially constant temperature.

(3) Details of Switching Control of Reciprocating Movement of Heat Transfer Medium by Displacer 8

Next, the timing of switching the movement (reciprocating movement) of the heat transfer medium by the displacers 8 is described in detail with reference to FIGS. 3 to 6. Although each figure illustrates the magnetic working body 11A, the same also applies to the magnetic working body 11B. Moreover, the following switching timing is mainly achieved by the shape of the cam 9 in the example.

First, in the present invention, when the magnetic working substances 13 of the magnetic working body 11A are magnetized (increase a magnetic field) as illustrated in FIG. 1, the heat transfer medium is moved to the high-temperature end 14 side from the low-temperature end 16 side of the magnetic working body 11A by the displacers 8 before magnetizing the magnetic working body 11A by the permanent magnets 6 as illustrated in FIG. 3. In this case, when time while the permanent magnets 6 are magnetizing the magnetic working substances 13 of the magnetic working body 11A (increase the size of the magnetic field to be applied) is defined as T1, the heat transfer medium (water) is moved to the high-temperature end 14 side from the low-temperature end 16 side of the magnetic working body 11A by the displacers 8 before time larger than 0 and equal to or smaller than 0.15×T1 when the permanent magnets 6 start to magnetize the magnetic working substances 13 (increase the size of the magnetic field to be applied) in the example.

Since the magnetic working substances 13 are not magnetized at this time, the temperature of the low-temperature heat transfer medium (indicated by W1 in each figure, W2 indicates the high-temperature heat transfer medium) flowing thereinto is lower than that in the case (dashed line L2) where the heat transfer medium is caused to flow thereinto simultaneously with the magnetization as indicated by the solid line L1 in FIG. 3. Thereafter, the magnetic working substances 13 of the magnetic working body 11A are magnetized by the permanent magnets 6 as illustrated in FIG. 4, and therefore the temperature is in a state indicated by the solid line L3 in FIG. 4. A temperature difference (L3−L1) between the magnetic working substances 13 and the heat transfer medium at this time becomes larger than a temperature difference (L3−L2) when the heat transfer medium is simultaneously caused to flow thereinto.

On the other hand, in the present invention, even after the magnetic working substances 13 of the magnetic working body 11A are demagnetized (reduce the magnetic field), the displacers 8 are not operated and the heat exchange between the heat transfer medium and the magnetic working substances 13 is continued as illustrated in FIG. 5. In FIG. 5, the dashed line L4 indicates the temperature of the heat transfer medium in this case and the dashed line L5 indicates the temperature of the heat transfer medium when the heat transfer medium is moved simultaneously with the demagnetization. The temperature is lower in the dashed line L4 than in the dashed line L5.

Thereafter, the heat transfer medium is moved to the low-temperature end 16 side from the high-temperature end 14 side of the magnetic working body 11A by the displacers 8 as illustrated in FIG. 6. In this case, when time while the permanent magnets 6 are demagnetizing (reduce the size of the magnetic field to be applied) the magnetic working substances 13 is defined as T2, the heat transfer medium is moved to the low-temperature end 16 side from the high-temperature end 14 side of the magnetic working body 11A by the displacers 8 after time equal to or larger than 0.25×T2 and equal to or smaller than 0.33×T2 after the permanent magnets 6 demagnetized (reduced the size of the magnetic field to be applied) the magnetic working substances 13 in the example. L6 in FIG. 6 indicates the temperature of the magnetic working substances 13 at this time.

As described above, the heat transfer medium is moved to the high-temperature end 14 side from the low-temperature end 16 side of each of the magnetic working bodies 11A and 11B by the displacers 8 before the permanent magnets 6 increase (magnetize) the size of the magnetic fields to be applied to the magnetic working substances 13 in the present invention. Therefore, before the size of the magnetic fields to be applied to the magnetic working substances 13 is increased, the low-temperature heat transfer medium can be sent into the magnetic working substances 13, and a temperature difference from the magnetic working substances 13 in which the temperature has increased by the subsequent magnetic field increase can be increased.

Thus, heat is efficiently exchanged between the magnetic working substances 13 and the heat transfer medium, the temperature gradient between the high-temperature end 14 and the low-temperature end 16 of each of the magnetic working bodies 11A and 11B can be increased, and the temperature change caused by the magnetocaloric effect of the magnetic working substances 13 can be effectively and efficiently utilized.

In this case, when time while the permanent magnets 6 are increasing the size of the magnetic fields to be applied to the magnetic working substances 13 is defined as T1, the displacers 8 move the heat transfer medium to the high-temperature end 14 side from the low-temperature end 16 side of each of the magnetic working bodies 11A and 11B before time larger than 0 and equal to or smaller than 0.15×T1 before the permanent magnets 6 start to increase the size of the magnetic fields to be applied to the magnetic working substances 13 in the example. Therefore, the temperature increase of the magnetic working substances 13 can be effectively utilized.

The heat transfer medium is moved to the low-temperature end 16 side from the high-temperature end 14 side of each of the magnetic working bodies 11A and 11B by the displacers 8 after the permanent magnets 6 reduce the size of the magnetic fields to be applied to the magnetic working substances 13. Therefore, the heat transfer medium can be moved after the size of the magnetic fields to be applied to the magnetic working substances 13 is reduced and the temperature of the heat transfer medium can be further reduced by the magnetic working substances 13 in which the temperature decreases by the reduction in the magnetic field.

Thus, the temperature reduction of the magnetic working substances 13 can be effectively utilized, the temperature gradient between the high-temperature end 14 and the low-temperature end 16 of each of the magnetic working bodies 11A and 11B can be increased, and the temperature change caused by the magnetocaloric effect of the magnetic working substances 13 can be effectively and efficiently utilized.

In this case, when time while the permanent magnets 6 are reducing the size of the magnetic fields to be applied to the magnetic working substances 13 is defined as T2, the heat transfer medium is moved to the low-temperature end 16 side from the high-temperature end 14 side of each of the magnetic working bodies 11A and 11B by the displacers 8 after time equal to or larger than 0.25×T2 and equal to or smaller than 0.33×T2 after the permanent magnets 6 reduced the size of the magnetic fields to be applied to the magnetic working substances 13 in the example. Therefore, the temperature reduction of the magnetic working substances 13 can be effectively utilized.

In the example, both the control of moving the heat transfer medium to the high-temperature end 14 side from the low-temperature end 16 side before magnetizing the magnetic working substances 13 and the control of moving the heat transfer medium to the low-temperature end 16 side from the high-temperature end 14 side after demagnetizing the magnetic working substances 13 are carried out but it is also effective to carry out only one of the controls without being limited thereto.

Moreover, the entire configuration of the magnetic heat pump device is also not limited to the example and the heat transfer medium moving device may also be configured by a circulating pump or a rotary valve in place of the displacer 8.

DESCRIPTION OF REFERENCE NUMERALS

• • 1 magnetic heat pump device
  • 2 magnetic heat pump AMR
  • 3 housing
  • 6 permanent magnet (magnetic field changing device)
  • 7 rotating body (magnetic field changing device)
  • 8 displacer (heat transfer medium moving device)
  • 9 cam (heat transfer medium moving device)
  • 11A, 11B magnetic working body
  • 12 duct
  • 13 magnetic working substance
  • 14 high-temperature end
  • 16 low-temperature end
  • 19, 22 heat exchanger
  • M motor

Claims

1. A magnetic heat pump device comprising: a magnetic working body which has a magnetic working substance having a magnetocaloric effect and in which a heat transfer medium is circulated;a magnetic field changing device changing a size of a magnetic field to be applied to the magnetic working substance;a heat transfer medium moving device causing the heat transfer medium to reciprocate between a high-temperature end and a low-temperature end of the magnetic working body;a heat exchanger on a heat dissipation side for causing the heat transfer medium on a side of the high-temperature end to perform heat dissipation; anda heat exchanger on a heat absorption side for causing the heat transfer medium on a side of the low-temperature end to perform heat absorption, whereinthe heat transfer medium moving device moves the heat transfer medium to the high-temperature end side from the low-temperature end side of the magnetic working body before the magnetic field changing device increases the size of the magnetic field to be applied to the magnetic working substance.

2. A magnetic heat pump device comprising: a magnetic working body which has a magnetic working substance having a magnetocaloric effect and in which a heat transfer medium is circulated;a magnetic field changing device changing a size of a magnetic field to be applied to the magnetic working substance;a heat transfer medium moving device causing the heat transfer medium to reciprocate between a high-temperature end and a low-temperature end of the magnetic working body;a heat exchanger on a heat dissipation side for causing the heat transfer medium on a side of the high-temperature end to perform heat dissipation; anda heat exchanger on a heat absorption side for causing the heat transfer medium on a side of the low-temperature end to perform heat absorption, whereinthe heat transfer medium moving device moves the heat transfer medium to the low-temperature end side from the high-temperature end side of the magnetic working body after the magnetic field changing device reduces the size of the magnetic field to be applied to the magnetic working substance.

3. A magnetic heat pump device comprising: a magnetic working body which has a magnetic working substance having a magnetocaloric effect and in which a heat transfer medium is circulated;a magnetic field changing device changing a size of a magnetic field to be applied to the magnetic working substance;a heat transfer medium moving device causing the heat transfer medium to reciprocate between a high-temperature end and a low-temperature end of the magnetic working body;a heat exchanger on a heat dissipation side for causing the heat transfer medium on a side of the high-temperature end to perform heat dissipation; anda heat exchanger on a heat absorption side for causing the heat transfer medium on a side of the low-temperature end to perform heat absorption, whereinthe heat transfer medium moving device moves the heat transfer medium to the high-temperature end side from the low-temperature end side of the magnetic working body before the magnetic field changing device increases the size of the magnetic field to be applied to the magnetic working substance, andthe heat transfer medium moving device moves the heat transfer medium to the low-temperature end side from the high-temperature end side of the magnetic working body after the magnetic field changing device reduces the size of the magnetic field to be applied to the magnetic working substance.

4. The magnetic heat pump device according to claim 1, wherein when time while the magnetic field changing device is increasing the size of the magnetic field to be applied to the magnetic working substance is defined as T1,the heat transfer medium moving device moves the heat transfer medium to the high-temperature end side from the low-temperature end side of the magnetic working body before time larger than 0 and equal to or smaller than 0.15×T1 before the magnetic field changing device starts to increase the size of the magnetic field to be applied to the magnetic working substance.

5. The magnetic heat pump device according to claim 2, wherein when time while the magnetic field changing device is reducing the size of the magnetic field to be applied to the magnetic working substance is defined as T2,the heat transfer medium moving device moves the heat transfer medium to the low-temperature end side from the high-temperature end side of the magnetic working body after time equal to or larger than 0.25×T2 and equal to or smaller than 0.33×T2 after the magnetic field changing device reduced the size of the magnetic field to be applied to the magnetic working substance.

6. The magnetic heat pump device according to claim 3, wherein when time while the magnetic field changing device is increasing the size of the magnetic field to be applied to the magnetic working substance is defined as T1,the heat transfer medium moving device moves the heat transfer medium to the high-temperature end side from the low-temperature end side of the magnetic working body before time larger than 0 and equal to or smaller than 0.15×T1 before the magnetic field changing device starts to increase the size of the magnetic field to be applied to the magnetic working substance, andwhen time while the magnetic field changing device is reducing the size of the magnetic field to be applied to the magnetic working substance is defined as T2,the heat transfer medium moving device moves the heat transfer medium to the low-temperature end side from the high-temperature end side of the magnetic working body after time equal to or larger than 0.25×T2 and equal to or smaller than 0.33×T2 after the magnetic field changing device reduced the size of the magnetic field to be applied to the magnetic working substance.